THE WATER SURVEY OF CANADA

Transcription

1 THE WATER SURVEY OF CANADA HYDROMETRIC TECHNICIAN CAREER DEVELOPMENT PROGRAM Lesson Package No. 16 Climatological Records For Streamflow Computations Patrice M. Pelletier Water Resources Branch Environment Canada 513, 269 Main Street Winnipeg, Manitoba Canada R3C 1B2

2 Copyright All rights reserved. Aussi disponible en français

3 TABLE OF CONTENTS 1.0 PURPOSE AND BACKGROUND OBJECTIVES THE HYDROLOGICAL CYCLE INTRODUCTION THE PRECIPITATION PROCESS THE EVAPORATION AND EVAPOTRANSPIRATION PROCESSES THE SURFACE RUNOFF PROCESS THE SUBSURFACE RUNOFF PROCESS ATMOSPHERIC ENVIRONMENT SERVICE DATA INTRODUCTION TEMPERATURE MEASUREMENT PRECIPITATION MEASUREMENT EVAPORATION MEASUREMENT EVAPOTRANSPIRATION ESTIMATION SOURCES OF CLIMATOLOGICAL DATA OTHER SOURCES OF CLIMATOLOGICAL DATA PROVINCIAL AND PRIVATE AGENCIES ATLASES WATER SURVEY OF CANADA U.S. NATIONAL WEATHER SERVICE METHODS USED TO REPRESENT CLIMATOLOGICAL RECORDS PLOTTING OF METEOROLOGICAL RECORDS Daily Precipitation Daily Temperature Example Exercise FACTORS AFFECTING THE SHAPE OF THE HYDROGRAPH USE OF CLIMATE DATA IN HYDROMETRIC COMPUTATIONS DATA ESTIMATION : WINTER ICE CONDITIONS Precipitation Temperature Computation of Streamflow Records Under Ice Conditions DATA ESTIMATION : MISSING PERIOD Hydrologic Comparison Rainfall Runoff Relations USE OF EVAPORATION DATA SUMMARY MANUALS AND REFERENCES MANUALS iii

4 9.2 REFERENCES APPENDIX A: PLOTTING OF DAILY PRECIPITATION AND TEMPERATURE...33 APPENDIX B: PLOTTING OF DAILY PRECIPITATION AND TEMPERATURE...48 iv

5 1.0 PURPOSE AND BACKGROUND The purpose of this lesson package is to show technicians how to compute or estimate streamflow records more accurately through the use of data banks and the latest analytical techniques. These techniques are essential for the routine analysis of streamflow records. They are also an invaluable tool for developing accurate estimates of missing or inconsistent hydrological records in the event of equipment failure. This lesson package should follow Lesson Packages No. 19 and No. 20, which deal with computations under open water and ice conditions. 1

6 2.0 OBJECTIVES Various processes of the hydrological cycle (precipitation, evaporation, evapotranspiration, surface and subsurface runoff) will be discussed to give the participants a better overall understanding of hydrology. In addition to this, the various types of climatological data used by Water Survey of Canada to facilitate the computation of streamflow records will be identified, including data on precipitation, air temperatures (maximum, minimum, and mean), water temperature and evaporation. The source of these data, the Atmospheric Environment Service (A.E.S.) daily and monthly reports and Water Survey of Canada records, will be identified.their purpose and use in hydrometric computations will be discussed and illustrated. Hydrologic techniques that use climatological data, such as the synthetic unit hydrograph and the rational method, will be described. As well, some of the instruments used by the Water Survey of Canada for measuring precipitation, evaporation, and air temperature will be briefly described. At the end of the session, the participants will be able to : 1. describe the hydrological cycle, its different processes, and its general impact on the corrections required when doing hydrometric computations; 2. describe where to get the information and whom to contact; 3. read climatological records and interpret them accurately; 4. describe how climatological records should be displayed and used for hydrometric computations; 5. describe the hydrologic techniques available for data estimation. 2

7 3.0 THE HYDROLOGICAL CYCLE 3.1 INTRODUCTION The hydrological cycle describes the processes of motion, loss, and recharge of the earth's waters. This continuum of the water cycle is illustrated in Figure 1. Figure 1: The hydrological cycle The hydrological cycle has neither beginning nor end. When water evaporates from the land, oceans, and other water surfaces, it temporarily becomes part of the atmosphere. The evaporated moisture is carried upwards and stored in the atmosphere until it precipitates and returns to the earth, over land or ocean. The precipitated water may be intercepted or transpired by plants. It may flow over the land as surface runoff or may percolate to deeper zones to be stored as ground water. Ground water will in turn flow out as springs, or seep into streams as runoff, and eventually evaporate into the atmosphere to complete the cycle. The complicated processes of precipitation, evaporation, transpiration, interception, infiltration, percolation, storage, and runoff are described below. 3.2 THE PRECIPITATION PROCESS Precipitation includes all forms of moisture falling from the atmosphere to the earth's surface. It is produced primarily from water vapor present in the air. Atmospheric moisture occurs in vapor, liquid, and solid form. It is replenished by evaporation and transpiration, and depleted by precipitation. Precipitation occurs when water vapor in the atmosphere cools and condenses to form water droplets or ice crystals that are too heavy to be sustained in the air. The nature of the Canadian climate ensures that all forms of precipitation are experienced. 1. Rain (liquid water droplets with a typical diameter of 1 mm) forms the largest portion of precipitation. 2. Snow is the next most prevalent form of precipitation, producing an estimated 50 percent of the total annual precipitation in the north country, 25 percent in the Prairies, and less than 10 percent on both coasts and in southern Ontario. 3

8 3. Hail (5 50 mm in diameter), sleet (a snow and rain mixture), dew (condensation of water vapor on objects), and hoarfrost (deposits of ice deposited like dew but at below 0ºC) contribute a small portion of Canada's total precipitation. 3.3 THE EVAPORATION AND EVAPOTRANSPIRATION PROCESSES Evaporation is an important process of the hydrological cycle. On a continental basis, approximately 75 percent of the total annual precipitation is returned to the atmosphere by evaporation and transpiration. The evaporation of water (the emission of water vapor from surfaces) and evapotranspiration (the transfer of water from soil to the atmosphere by transport through plants and subsequent evaporation) are the processes by which the atmosphere is recharged after loss by precipitation. Some water is caught by plants, temporarily stored, and later evaporated directly to the atmosphere; this is known as interception loss. Evaporation of water from a free surface is governed primarily by climatic factors, such as humidity, air temperature, wind speed, solar radiation, and cloud cover, and by the nature of the evaporating surface. The amount of water transferred to the atmosphere by evapotranspiration depends on factors such as soil and vegetation types, as well as climate. 3.4 THE SURFACE RUNOFF PROCESS Water may follow many different paths on its way to the sea, depending on how it reacts with the surface on which it falls. Some will fall on streams or lakes and run off directly to the ocean. Some surface water will collect in surface depressions, then overflow and move down slopes in thin films and tiny streams, which eventually reach an established stream. 3.5 THE SUBSURFACE RUNOFF PROCESS When water encounters the soil surface it may become surface runoff or it may infiltrate the soil and become part of the subsurface runoff process. Surface runoff occurs only if the precipitation intensity exceeds the infiltration rate of the soil and the interception and evaporation losses. Water that infiltrates the soil surface may do one of three things : 1. it may interflow just under the surface and discharge directly into a stream without joining the main ground-water body; 2. it may percolate down to the ground-water table and flow slowly through ground-water flow systems for periods varying from days to thousands of years before reaching a stream channel or an ocean; or 3. it may join the unsaturated zone by forming soil moisture that eventually returns to the atmosphere via evaporation and evapotranspiration. 4

9 4.0 ATMOSPHERIC ENVIRONMENT SERVICE DATA 4.1 INTRODUCTION Weather records are a valuable source of information for estimating flow characteristics during periods when data are missing or unobtainable. Such records are also useful for computing the relative backwater from ice during a period of recorded gauge heights. The largest source of published climatological data in Canada is the Atmospheric Environment Service (A.E.S.), of Environment Canada. A.E.S. publishes information from more than 2000 climatological stations yearly, collecting data on precipitation, air temperature, evaporation, snow cover, and snowfall. The complete list is presented in Table 1. To describe the type of station where a specific climatological element is collected, a coding system is used. The code numbers (1 9) are presented below, followed by the approximate number (in parentheses) of stations operating as of July 1 st, 1982 : 1. Principal climatological stations (333) 2. All climatological stations with normals (2700) 3. Stations that prepare a monthly or annual meteorological summary (61) 4. Selected network stations for radiation (50), sunshine (307), soil temperature (70), wind (239), evaporation (138) 5. Upper air stations (34) 6. All climatological stations in present operation (2374) 7. Regional stations 8. Climatological stations present and past (7600) 9. Selected stations for certain climatological elements. To gain a better understanding of climatological elements and their use in streamflow computation, let us briefly examine how temperature, precipitation, evaporation, and evapotranspiration are measured and/or estimated. Table 1. List of Climatological Elements Air quality Barometric pressure sea level, station Blowing dust or sand Blowing snow Ceiling Cloud amount Corn heat units Ozone Precipitation Rainfall Relative humidity Smoke or haze Snow cover Snowfall 5

10 Degree days (growing) above base 5ºC or 42ºF Degree days (heating) below base 18ºC or 65ºF Degree days (other) Dew-point temperature Evaporation Fog Freeze-up and breakup Frost Hail Ice pellets Ice thickness Soil temperature Solar radiation Sunshine Temperature Thunderstorms Upper air Vapor pressure Visibility Water balance Wet-bulb temperature Wind Mixing ratio 4.2 TEMPERATURE MEASUREMENT To measure air temperature properly, thermometers must be placed where air circulation is relatively unobstructed, and yet where they are protected from direct rays of the sun and from precipitation. Thermometers are placed in white, louvered, wooden instrument shelters through which the air can move readily. The shelter location must be typical of the area of which the measured temperatures are to be representative. Except for a few stations equipped to obtain continuous or hourly temperatures, most stations record only the daily maximum and minimum temperatures. The minimum thermometer, or the alcohol-in-glass type, has an index that remains at the lowest temperature occurring since its last setting. The maximum thermometer has a constriction near the bulb that prevents the mercury from returning to the bulb as the temperature falls and is thus able to register the highest temperature since its last setting. The thermograph, with either a bimetallic strip or a metal tube filled with alcohol or mercury for its thermometric element, makes an automatic record on a chart. Air temperature data from A.E.S. are available for different time periods. A list outlining the types of air temperature data available is shown in Table 2. Table 2. Temperature Data Available from A.E.S. Time Period Temperature Station Code Hour Dry-bulb readings 3 Day Maximum Toronto area maximum and standard deviation Minimum 1,3,6,7 7 1,3,6,7 7 6

11 Week Month Toronto area minimum and standard deviation Mean Number of days with freezing Highest and lowest Mean daily Mean daily and difference from normal Mean daily Mean daily maximum Mean daily minimum 1,3,6 1 1,7 1,7 1,6 3,6 3,6,7 3,6,7 4.3 PRECIPITATION MEASUREMENT Precipitation reporting stations in Canada are equipped with one or both of the A.E.S. rain gauges, namely the A.E.S. standard rain gauge and the tipping bucket rain gauge. 1. The standard rain gauge is used to collect and measure the amounts of all types of precipitation (rain, drizzle, freezing rain, and hail) to the nearest 0.2 mm. 2. The tipping bucket rain gauge, on the other hand, is used only to collect liquid precipitation; it cannot function when loaded with frozen precipitation. Snowfall is measured by means of a standard snow ruler. The depths of freshly fallen snow are measured at a number of representative points, and the average of these is then recorded to the nearest 0.2 cm. At most ordinary climate stations, the water equivalent of the snowfall is obtained by simply dividing the snowfall amount by 10. However, at principal climate stations, and at some ordinary stations equipped with a Nipher-shielded snow gauge, the actual water equivalent of the snowfall is obtained by melting the snow collected in the gauge. Total precipitation is defined as the rainfall amount plus the measured water equivalent of the newly fallen snow. At principal stations precipitation observations are taken four times daily. At most other stations, precipitation measurements are made at least twice daily, in the morning and in the late afternoon. At a few stations only one observation is taken daily. After the end of each month the observational documents are sent to A.E.S., where the data are processed and checked for completeness and accuracy before they are archived and published. Table 3 shows what precipitation data are available from A.E.S. for different time periods. Time Precipitation Period Hour Occurrence Total corrected from recording gauge 6-hourly totals at 4 synoptic hours Table 3. Precipitation Data Available from A.E.S. Station Code Units Day Total 1,2,3,4,7 mm Total, corrected from recording gauges for 24-hour period 4 mm Total from digital recording gauges 4 in. Maximum total for duration of 5, 10, 15, 30 min, and 1, 2, 6, and 12 h 4 mm mm mm 7

12 Total recorded by the Leupold and Stevens and the Universal weighing gauges 4 mm Number of days with freezing precipitation and precipitation 1 mm Week Total Extreme total Month Total 3,4,6,7 mm Total and percent of normal 1,6 mm Total previous year 3 mm Total from digital recording gauges 4 in. Total recorded by the Leupold and Stevens and the Universal weighing gauges 4 mm Greatest in one day or 24 hours with date 1,3,6 mm Greatest in one day with date previous year 3 mm Maximum amount and dates of occurrence for durations 30 min, 60 min, and 2, 6, 12, 24 h as recorded by Fischer and Porter automatic recording gauge, Leupold and Stevens gauge and the Universal Weighing gauge 7 1 mm mm 4 in., mm 4.4 EVAPORATION MEASUREMENT The amount of water evaporated constitutes a direct loss from both surface and subsurface reservoirs. Estimates of these losses are needed to perform accurate studies concerning water apportionment or balance and reservoir operation. There are several methods that may be used to estimate the amount of evaporation from a free water surface. In general, these can be grouped as measurement from evaporation pans, water budget, mass transfer, empirical formulae, and energy balance. Let us examine evaporation pans and how they are used to provide estimates of the amounts of evaporation from lakes and reservoirs. Various types of pan exposures may be used, including sunken pan, floating pan, and surface pan. The most common type of evaporation pan is the surface pan. The standard surface pan used in Canada is the U.S. Weather Bureau Class A pan. This pan is 1.2 m (4 ft) in diameter and.25 m (10 in.) deep. The rate of evaporation in the pan is determined by records of the water level changes in the pan that account for the amount of water added by rainfall or by artificial filling. The rate of lake evaporation is determined by applying a coefficient to the readings taken from the standard surface pan. Although the pan coefficient varies, the standard in Canada is Corrections for advected energy must also be applied. Evaporation data are available from A.E.S. for different time periods. Table 4 outlines the types of evaporation data available from A.E.S. Time Period Description Table 4. Evaporation Data Available from A.E.S. Station Code Day Net water loss from pan and calculated lake evaporation 4 mm Mean, maximum, and minimum air temperature; and water temperature 4 C Units 8

13 Total wind run, and precipitation 4 km, mm Month Total net water loss from pan 4 mm Daily mean wind speed, water and air temperature 4 km/h, C Total calculated lake evaporation 4 mm Tabulation of total net pan water loss, total lake evaporation, total wind run, total precipitation, and total water added and removed Tabulation of daily mean wind run, mean water temperature, mean air temperature, and mean station pressure 4 mm, km 4 km, C, kpa Total lake evaporation Great Lakes 7 mm Year Total lake evaporation Great Lakes 7 mm Long Mean potential evapotranspiration 9 mm period (week) Long Mean, maximum, and minimum total lake evaporation with dates Great Lakes 7 mm period (month) Normal potential and actual evapotranspiration from the climatic water balance 1 mm Long period (year) Normal class A pan evaporation 9 mm Normal ( ), mean, and standard deviation of lake evaporation 4 Abstract of normal ( ), mean, and standard deviation of lake evaporation 4 Mean, maximum, and minimum total lake evaporation with dates Great Lakes 7 mm Normal potential and actual evapotranspiration from the climatic water balance 1 mm Normal class A pan evaporation 9 mm Normal ( ), mean, and standard deviation of lake evaporation 4 Abstract of normal ( ), mean, and standard deviation of lake evaporation 4 mm 4.5 EVAPOTRANSPIRATION ESTIMATION Evapotranspiration includes the sum of water volume used by both evaporation and transpiration processes. Obviously, many of the elements (primarily climatic ones) that influence the amount of evaporation from a free water surface also affect the amount of evapotranspiration. These elements include solar radiation intensity and duration, wind conditions, relative humidity, cloud cover, and atmospheric pressure. The type of soil, and the type and extent of vegetation also govern the rate of evapotranspiration from an area. Many methods are available to estimate the rate of evapotranspiration. They include : 1. soil moisture depletion studies on small plots 2. tank and lysimeter experiments 3. study of ground-water fluctuations 4. differences of inflow-outflow measurements 5. empirical constants applied to tank evaporation measurements 9

14 6. theoretical methods based on either the physics of vapor transfer or of heat energy 7. soil moisture budget 8. correlations of environmental climatic elements with irrigation and precipitation records 9. effective heat or day degree method. 4.6 SOURCES OF CLIMATOLOGICAL DATA Information regarding publication contents and format, as well as station histories and related records, may be obtained by applying to the nearest regional office or to the Canadian Climate Centre of the Atmospheric Environment Service. Generally, the front-line supplier of climate information is the regional climate specialist or the equivalent. For enquiries of an inter-regional, national, or international nature, contact the Canadian Climate Centre at Downsview, Ontario.Regional Offices Climate Services Atmospheric Environment Service Suite 700, 1200 West 73rd Avenue Vancouver, B.C. V6P 6H9 Phone: (604) Ontario Climate Centre Atmospheric Environment Service Environment Canada 25 St. Clair Avenue East, Room 301 Toronto, Ontario M4T 1M2 Phone: (416) Western Region Atmospheric Environment Service Twin Atria Building th Avenue Edmonton, Alberta T6B 2Y3 Phone: (403) Service climatologique Environment Canada 100 Alexis Nihon Blvd., 3rd Floor Ville Saint-Laurent, Québec H4M 2N6 Phone: (514) Winnipeg Climate Centre Environment Canada 266 Graham Avenue, Room 1000 Winnipeg, Manitoba R3C 3V4 Phone: (204) Atlantic Region Atmospheric Environment Service 1496 Bedford Highway Bedford, Nova Scotia B4A 1E5 Phone: (902) Canadian Climate Centre Atmospheric Environment Service 4905 Dufferin Street Downsview, Ontario M3H 5T4 Attn: Climatological Services Division Phone: (416)

15 Figure 2 is a map showing the six regions of the Atmospheric Environment Service. Figure 2: A.E.S. regions in Canada The following publications are available from the Atmospheric Environment Service : Handbook on Climate Data Sources of the Atmospheric Environment Service (Phillips, 1982) This handbook describes the most recent climate data available in both published and unpublished form. Included is information on the publications produced by the Atmospheric Environment Service, the type of data available, the periods of record, the extent of Canada covered, and where and how to acquire the publications and data. An important feature of this handbook is the display of sample data in abbreviated form. The latest handbook is dated Climatological Station Data Catalogue (Environment Canada, 1981) This catalogue lists all Canadian climatological stations, active and inactive. It also contains information about the type of data available to the end of The series contains six volumes, one for each geographical area. Climatic Atlas Canada (Environment Canada, 1986) This atlas depicts the climate of Canada by means of maps. Each element of the climate is presented as a separate series of maps. The distribution of the means, extremes, and frequencies, as appropriate, is shown for each month and for the year, using data from 1951 to This publication is an update of the 1967 series. The atlas contains 400 maps grouped into ten sections : temperature and degree days, precipitation, wind, solar radiation and sunshine, cloud cover, atmospheric pressure, humidity, soil temperature and evaporation, snow cover and ice cover, and days with variables such as fog and hail. Each map series includes a brief text containing definitions, the means of obtaining the various data, and the method of analysis. Each series also presents a note on how major climate controls such as topography and water bodies affect the elements treated in that section. 11

16 Also available from A.E.S. are the following current climatological data periodicals : Climatic Perspectives This monthly publication summarizes the weather across Canada and is printed within two weeks after the close of each month. In addition to a narrative summary of the weather for the month, there are four maps : mean temperature, departure from normal temperature, total precipitation, and percentage of normal precipitation. Table 5, a sample from Climatic Perspectives, shows the kinds of data collected at surface synoptic stations. Data are based on unverified reports from about 250 surface synoptic reporting stations of the Atmospheric Environment Service. There are also 41 Agriculture Canada research stations that contribute weather data to Climatic Perspectives. These agriclimatological stations give dew-point temperature instead of vapor pressure, and growing degree days instead of heating degree days (see Table 6). Monthly Meteorological Summary The Monthly Meteorological Summary provides a convenient and systematic selection of provisional weather data in microfiche form. As of May 1982, 61 stations were issuing monthly summaries; 40 of them were also issuing an annual summary (Table 7). Pages 1 and 2 show standard data tables of daily temperature degree days, relative humidity, thunderstorms, precipitation, snow on the ground, wind, and bright sunshine (Table 8). Means, extremes, and normals for the month are also included. Optional tables may include hourly averages for dry-bulb temperature, precipitation occurrences, prevailing wind direction and speed, and wet-bulb temperature. Others may include a summary of the month's weather or other relevant information if there are local or regional requirements for this. Issues are published approximately one to two weeks after the end of the month. Table 5: Climatic Perspectives Surface Synoptic Stations (250) 12

17 Table 6: Climatic Perspectives Research Stations (41) Table 7: List of Stations Preparing Monthly and Annual Summaries 13

18 Table 8: Monthly Meteorological Summary Table 9: Regional Monthly Summary 14

19 Regional weather summaries are also available : All regional offices of A.E.S. produce climatological summaries and reports at the end of the month. Generally they include a limited number of stations and climatological elements. Some quality control measures are carried out to ensure reasonable accuracy and completeness of data. Table 9 shows a monthly summary of temperature, precipitation, and snow on the ground for climatological stations in a region. Table 10 shows the daily weather bulletin issued by the Winnipeg Weather Office. Current data are published for about 100 stations in the grain-growing areas of western Canada and the north central United States. An example of a weekly weather summary is shown in Table 11. Each region also prepares a narrative of the past month's weather. These weather highlights are usually available by the third working day after the close of the month. For more information regarding regional data sources, readers are advised to contact the appropriate regional office directly. Table 10: Daily Weather Bulletin Table 11: Weekly Weather Summary 15

20 5.0 OTHER SOURCES OF CLIMATOLOGICAL DATA 5.1 PROVINCIAL AND PRIVATE AGENCIES A.E.S. is not the only Canadian source of climate data. Provincial agencies and several private companies also collect climate data. Much of this information is not published and is therefore only available from the agency collecting it. Precipitation data are dependent on many factors. Therefore, before using these data, they should be studied carefully to determine the type of instrument used and its exposure. 5.2 ATLASES Several atlases contain hydrological data of use when computing streamflow records. Hydrological Atlas of Canada The Hydrological Atlas of Canada (Fisheries and Environment Canada, 1978) presents maps of Canada's atmospheric, surface, and underground water resources, and the factors that affect water movement within the hydrologic cycle. For example, maps of the following are presented in the atlas : Precipitation networks Annual precipitation Snow cover monitoring networks Annual snowfall Dates of formation and loss of snow cover Mean maximum depth of snow and time of occurrence Radiation Air temperature monitoring network Mean January daily temperature Mean July daily temperature Winds Mean annual lake evaporation Freeze-up and breakup of rivers and lakes. The National Atlas of Canada Maps of precipitation, temperature, snow cover, etc., as outlined above are also found in The National Atlas of Canada (Energy, Mines and Resources Canada, 1974). Provincial Atlases Some of the Canadian provinces have also published hydrologic atlases in which climatological maps have been included. For example, an Ontario publication entitled Water Quantity Resources of Ontario (Ontario Ministry of Natural Resources, 1984) includes 26 coloured maps, and maps that highlight mean annual precipitation, snowfall, and lake evaporation. 16

21 5.3 WATER SURVEY OF CANADA The Water Survey of Canada (WSC) has been collecting continuous water temperature records at selected gauging stations since 1959 (26 stations in 1979). At one time the daily maximum, minimum, and mean water temperatures were extracted from the charts by hand. In 1979, it was decided to automate this process, using a program called TGRAPH (Environment Canada, 1980b). This program can process records in either degrees Fahrenheit or Celsius and produce computer listings of water temperature data in degrees Celsius. Outputs from the program are shown in Figure 3. Several district offices have published records of water temperature over the years. Water and air temperatures are also available from the WSC meter (discharge measurement) notes. Figure 3(a): Outputs from TGRAPH Figure 3(b): Outputs from TGRAPH 5.4 U.S. NATIONAL WEATHER SERVICE The largest single source of published climatological data in the United States is the U.S. National Weather Service. The main sources of data on temperature, precipitation, humidity, wind, etc. are the monthly bulletins entitled Climatological Data, published by the National Climate Data Centre of the National Oceanic and Atmospheric Administration (NOAA). Weekly and monthly maps may be found in Weekly Weather, Crop Bulletins, and Monthly Weather Review. Information regarding publication content and format, as well as station histories and related records may be obtained from the state office or from the following address : National Climate Data Centre National Oceanic and Atmospheric Administration Asheville, NC U.S.A. 17

22 6.0 METHODS USED TO REPRESENT CLIMATOLOGICAL RECORDS 6.1 PLOTTING OF METEOROLOGICAL RECORDS Daily Precipitation Using form M or equivalent : Plot daily total precipitation (rainfall plus snowfall) obtained from the appropriate meteorological station, i.e., the one closest to the gauging station. Plot the precipitation on the upper part of the hydrograph sheet, using a bar to represent the total precipitation. Indicate the cause (rain or snow) of the highest daily events. Use a scale of 1 cm = 10 mm or 20 mm of total precipitation (Figure 4). Figure 4: Daily precipitation plot Daily Temperature Using form M or equivalent : Plot daily mean temperature (or maximum and minimum) obtained from the appropriate meteorological station, i.e., the one closest to the gauging station. Plot the temperature on the upper part of the hydrograph sheet, just below the precipitation bargraph. If mean temperature is plotted, join each point with a line. If maximum and minimum temperatures are plotted you can either join each minimum temperature with a line, and each maximum temperature with a line, or join the minimum and maximum temperatures with a line. Use a scale of 1 cm = 10ºC or 20ºC (Figure 5). Figure 5: Daily air temperature plot 18

23 6.1.3 Example Exercise The plotting of daily precipitation and temperature data can be illustrated through an example. Using the information provided in Appendix C, complete Figure C- 1. Verify with reference to Figure FACTORS AFFECTING THE SHAPE OF THE HYDROGRAPH The results of the different hydrologic processes, as described in Section 3 of this report, influence the shape of a hydrograph. The influence of these processes on the shape of the hydrograph will now be described, so that the hydrometric technician will be able to recognize these events when computing streamflow records. This material is taken from Environment Canada (1984), Methods for the Estimation of Hydrometric Data, Appendix A. Figure 6: Daily hydrograph for Red River near Sainte-Agathe A streamflow hydrograph is a graphical presentation of the discharge of a stream versus time. Since discharge can include contributions from surface runoff, interflow, groundwater flow, channel precipitation and natural or artificial regulation, the hydrograph may take on a multitude of shapes. An understanding of the many factors that influence the shape of the hydrograph is important when computing streamflow data. A.1 Hydrograph Characteristics A typical hydrograph for a single runoff event is shown in Figure 7. It is characterized by a period of increasing discharge (rising limb) culminating in a peak or crest, and a period of decreasing discharge (recession limb). The rising limb extends from the beginning of surface runoff to the first inflection point and is generally concave upward. The shape of the rising limb is dependent upon the characteristics of the time area histogram for the basin and the duration, intensity and uniformity of inflow (rainfall and/or snowmelt). The crest segment extends from the inflection Figure 7: Elements of a typical hydrograph (Gray, 1970) point on the rising limb through the peak to a corresponding inflection point on the recession limb. The recession limb is a period of decreasing discharge extending from the inflection point on the falling limb to base flow. In general, most streams are subject to contribution from groundwater and interflow, resulting in a gradually decreasing slope for the recession because of the varying time lags associated with the different components of flow. The shape of the recession limb is essentially dependent upon the physical features of the basin. 19

24 A.2 Factors Affecting Hydrograph Shape A.2.1 Climatic Factors a. Precipitation intensity and duration : Precipitation has an effect on the volume, peak discharge and duration of runoff. An increase in rainfall intensity will generally increase the peak discharge and volume but will have little effect on the time base of the hydrograph. For a large basin, variation of rainfall intensity usually has an insignificant effect on hydrograph shape. An increase in rainfall duration often has the effect of increasing the contributing area of a drainage basin as surface storage is filled and will lengthen the time base of the hydrograph. b. Distribution of precipitation : Precipitation near a gauging station will normally produce a more rapid rise, sharp peak and rapid recession. The same precipitation in the upper reaches of the basin produces a lower, broader peak. c. Direction of storm movement : A storm moving downstream over a basin will produce a higher, sharper peak than a storm moving upstream. d. Type of precipitation, type of storm, temperature : A snowmelt hydrograph will generally produce a shape which has a broader time base than a rainfall hydrograph, often with diurnal fluctuation. The rate of runoff is lower from snowmelt because of lags due to the nature of the snowpack and its distribution as well as the attenuating effects of cool evening temperatures. Conversely, an extended period of warm temperatures, as a result of a large warm air mass settling over a basin, can generate unusually sharp peaks from snowmelt. An increase in meltwater temperature because of increased solar absorption during a snowmelt period is significant in exposed areas such as south-facing valley slopes, urban areas and cultivated fields. This warmer water increases the rate of snowmelt and contributions from melting channel ice. Runoff from snowmelt during periods of relatively low daytime temperatures and freezing nights will tend to be sporadic and unpredictable because the runoff period is extended and a greater opportunity for contribution to subsurface supplies is afforded. Under these melt conditions a cyclic effect will normally show up on the chart trace. Snow dams and ice jams have the effect of altering the shape of the hydrograph to a larger degree for a small basin than for a larger basin. e. Antecedent conditions : Antecedent conditions have an effect owing to a change in the groundwater component and the contributing area of a basin. High antecedent precipitation increases the groundwater component and may increase the contributing area as available surface increases. 20

25 7.0 USE OF CLIMATE DATA IN HYDROMETRIC COMPUTATIONS As mentioned previously, climatological records may be used to : 1. compute the relative backwater from ice during a period of recorded gauge height, using the : backwater method, or the effective gauge-height method, or the K-factor method. 2. estimate flow during periods of missing data. Once the meteorological factors have been plotted on the hydrograph, it is necessary to examine how this information can be used to compute relative backwater due to ice and to estimate missing data. 7.1 DATA ESTIMATION : WINTER ICE CONDITIONS The quantity and distribution of winter streamflow are the results of the combination of factors that may be classified as climatic, geologic, topographic, and vegetational. The climatic factors are precipitation, temperature, barometric pressure, and wind. As precipitation and temperature are the most important factors, they will be described in more detail Precipitation Streamflow during the winter is supplied by precipitation directly, in the form of rain or snow, and indirectly, from melting snow and from ground water. Precipitation in the form of snow does not add perceptibly to the runoff of an area until the local temperature rises above the freezing point. Rain falling on frozen ground not covered with snow will run off quickly. Rain falling on snow gradually increases the water content of the snow to the point of saturation, when it will run off Temperature When the temperature falls below the freezing point, a certain amount of surface water is frozen. With continued low temperatures, the newly formed ice will gradually increase in thickness according to the duration of the cold period. When higher temperatures cause the ice to melt in the spring, the water from the melting ice will join the runoff from spring rains and melting snow to increase the spring floods. The amount of water held in storage as ice in stream channels and in shallow ponds may be considerable, particularly for stream channels where the natural runoff per square kilometre is low. The freezing of the water also temporarily affects streamflow by suddenly increasing friction. This causes the flow at a given cross section to decrease until the winter regime has been established. Therefore, at the beginning of each cold period streamflow will drop suddenly, but will increase to some extent later Computation of Streamflow Records Under Ice Conditions The presence of ice at a stream's control causes the gauge height to rise without an increase in flow. This makes the computation of discharge a complex and highly subjective process, different for each gauging station in the country. One method of computation will now be described, showing how climatic records are used in the computation of 21

26 streamflow records under winter ice conditions. The records of temperature, precipitation, and water surface gauge heights are plotted on graph paper (form M or equivalent). Following this step a correction is applied to the daily gauge heights to ensure that an accurate open water stage discharge relation is determined. The correction value to be applied to the daily gauge heights will vary from one measurement time to another. The proper correction value is estimated by comparing the gauge height plot with the temperature, precipitation, and ice plots. This method has the obvious advantage of enabling the technician to compare the discharge directly with temperature, which is the most important factor affecting winter streamflow. The use of this and other methods is illustrated in Lesson Package No. 20, Computation of Daily Discharges (Ice Conditions). Ice formation is also dependent on many other factors such as the thickness and continuity of the ice cover. The thickness of snow cover on the ice and the temperature of the incoming water will also have an important influence on the strength and duration of ice cover. 7.2 DATA ESTIMATION : MISSING PERIOD There are several techniques for reconstructing periods of discharge records at a gauge site by using climatological records. Techniques are available to estimate peak flow caused by rainfall, or by snowmelt, or by a combination of the two events. Some of these techniques are briefly described below. To estimate peak discharges from catchment areas, present methods (Gray, 1970) may be grouped as indicated in Table 12 note not all these methods require climatological records to be used quantitatively. Table 12. Methods Used to Estimate Peak Discharge Catchment area (sq. mi) < 1 Methods commonly used in hydrology studies Infiltration approach Rational method < 100 Overland flood hydrograph Rational method Unit hydrographs Flood frequencies Flood peaks vs drainage area Unit hydrographs Flood frequencies Flood peaks vs drainage area > 2000 Flood routing Flood frequencies Flood peaks vs drainage area. 22

27 7.2.1 Hydrologic Comparison One of the techniques used to reconstruct missing periods of discharge records at a gauge station involves the use of hydrologic comparisons with records at one or two nearby stations. Flood peaks in particular, especially those caused by widespread rainfalls rather than by localized cloudburst activity, often have a high degree of correlation. Hydrographic comparisons of concurrent peakflows caused by various storm events can be made between two or more stations to establish the mutual relations of these peaks. The relations between the hydrographs of adjacent gauging stations can provide a good means for estimating missing discharges. These hydrometric relations, whether simple-linear or multiple-linear regressions, can be determined by well-established statistical procedures, either mathematically or by graphical analysis Rainfall Runoff Relations Unit and Synthetic Unit Hydrograph The unit hydrograph, originally called a unit graph, may be defined as the hydrograph for a given basin of a unit volume of surface runoff produced by precipitation of uniform intensity occurring over a unit of time. The unit volume is taken as 1 inch (or 1 cm) of precipitation excess over the entire basin. A unit hydrograph is derived for a given site by study of past storm events. It may be used to obtain a peak-flow value on the basis of rainfall information for a given storm over the basin. Reliable information on the areal extent and the depth and distribution of rainfall over the basin is needed, as well as the stage and discharge hydrographs resulting from these storms. The fundamental principles of the unit hydrograph are presented in abbreviated form in Figure 8. Figure 8(a): Principles of the unit hydrograph (U.S. Department of the Interior, 1965) Figure 8(b): Principles of the unit hydrograph (U.S. Department of the Interior, 1965) 23

28 Figure 8(c): Principles of the unit hydrograph (U.S. Department of the Interior, 1965) While the unit hydrograph is a useful hydrologic technique, it may not be easily applied to all regions. The theory behind this concept and an example calculation are included in Appendix C. Rational Formula Many empirical formulas have been developed over the years to estimate flood peaks. The oldest one is the rational formula, which is given by : Q p = c i A where Q p is the peak flow (cfs) c is runoff coefficient (runoff/rainfall) i is rainfall intensity (in./hr) of a storm whose duration is equal to the time of concentration of the basin A is drainage area in acres The equation is also shown in the form : Q p = 640 c i A where Q p is the peak flow (cfs) A is drainage area in square miles In SI units, the rational formula is : Q p = c i A where Q p is the peak flow (m³/s) i is rainfall intensity (mm/h) A is drainage area (km²) 24

29 This equation was first used in Ireland in urban engineering by Mulvaney in The use of the rational formula is limited to very small watersheds (less than 5 sq. mi. or 13 km²). In the rational formula, it is assumed that the rainfall intensity is uniform over the entire watershed for the duration of the storm. This condition is seldom completely fulfilled in nature. The reasoning of the method states that if a rainfall of uniform intensity and unlimited duration falls on a basin, the runoff rate per unit area will reach a maximum q p = (Q p A) = ci at the time of concentration, t c, and then will remain constant. The rainfall intensity i is obtained from nearby weather stations for a storm of duration equal to the time of concentration, tc, of the watershed. The time of concentration is defined as the time required for the water to travel from the hydraulically most distant point of a watershed to the watershed outlet. The time of concentration in hours may be estimated from the Kirpich formula : t c = (L 0.77 S ) where L is S is the maximum length of travel of water (ft) the slope, equal to H/L, where H is the difference in elevation between the most remote point on the basin and the outlet (ft). Experience is required in estimating the value of c, the runoff coefficient. The value of c ranges from 0.1 for flat grassy fields with highly permeable soil to 0.95 for paved surfaces. Representative values of the runoff coefficient are given in Table 13. Note the rational formula yields values of the peak discharge provided the rainfall lasts long enough so that the runoff has an opportunity to travel from the remotest point in the catchment to the point of concentration (the outlet). Table 13. Values of Runoff Coefficient c (Sangal, 1986) Runoff Coefficient c Topography and Vegetation Open Sandy Loam Clay and Silt Loam Tight Clay Woodland Flat (0% to 5% slope) Rolling (5% to 10% slope) Hilly (10% to 30% slope) Pasture 25

30 Flat Rolling Hilly Cultivated Flat Rolling Hilly Urban areas 30% impervious 50% imperviou s 70% imperviou s Flat Rolling Streets, roofs, and other paved areas Figure 9 is a flow chart outlining the procedure to use when applying the rational formula. Computer Modelling Hydrologic simulation models (e.g., rainfall runoff models) are mathematical descriptions of the response of a surface water system to the physical processes affecting the system. They may also be used to estimate missing data periods. However, the time required to calibrate such models is appreciable. Precipitation runoff models, like the USGS-PRMS (a deterministic physical-process modelling system) may be used to evaluate how various combinations of precipitation, climate, and land use impact on surface water runoff, sediment yields, and general basin hydrology. Through the use of the USGS-PRMS model, basin response to normal and extreme rainfall and snowmelt Figure 9: Flow chart for the rational formula (Schulz, 1973) can be evaluated for various combinations of land use. Factors such as changes in the water-balance relationship, flow regimes, flood peaks and volumes, soil water relationships, sediment yields, and ground water recharge can all be simulated on various combinations of land use with this model system. In order to simulate a realistic response, each component of the hydrologic cycle is expressed in the form of known physical laws or 26

31 empirical relationships that can be interpreted as measurable watershed characteristics. Within the Water Resources Branch, a computer program known as BSTOR (Shiau and Steingass, 1985) has been developed for the analysis of basin storage and water balance using climatological estimates of areal evapotranspiration. The rationale behind BSTOR is as follows. The water balance equation for a drainage basin states that the precipitation (P) less runoff (R) less evapotranspiration (ET) is equal to the change in storage (CS). The analysis of the change in storage is usually not possible because only precipitation and runoff have been routinely observed or estimated. The direct measurement of changes in storage on a monthly, seasonal, or even annual basis is too expensive to contemplate and practically impossible on a basin scale. BSTOR was developed as an alternative technique. The program uses Morton's evapotranspiration model to compute evapotranspiration on the basis of routine climatological observations. The current version of BSTOR computes the basin water balance and storage change on a monthly basis. The mass curve ordinates of mean precipitation, evapotranspiration, runoff, and storage are computed and plotted for any sequence of years. The monthly changes in total basin storage can also be plotted continuously for the detection of trends and identification of possible causes (see Figure 10). The total basin storage includes solid storage in snow, tension storage in the unsaturated soil, and gravity storage in lakes and in the saturated ground water zone. For each province, a handbook has been prepared containing monthly values (for specific sites) of dew point temperature, temperature, sunshine hours, net solar radiation, and evapotranspiration (see Figure 11). In summary, BSTOR may be used to investigate the variability of streamflow by accounting for climatic elements such as precipitation and evaporation. It can also be a valuable tool for detecting alterations in a streamflow regime caused by changes in land use or by data computation errors. Figure 10: Time series plot of water balance components Figure 11: Variation in monthly estimates of areal evapotranspiration 27

32 7.3 USE OF EVAPORATION DATA The purpose of this section is to briefly describe the methods used by the Water Resources Branch to estimate evaporation, particularly as it relates to apportionment of boundary waters. The international apportionment of boundary waters was formally established by the Boundary Waters Treaty (1909), which defined the division of waters between Canada and the U.S.A. Later, the Prairie Province Water Board Master Agreement on Apportionment (1969) defined the division of waters between Alberta, Saskatchewan, and Manitoba. The treaty and the agreement both stipulate that the upstream and downstream parties share equally the natural watercourse flow as determined by calculations performed at the boundary. Natural flow can be defined as the rate of flow that would occur without man's influence. In very general terms, the natural flow is computed by adding all water that is diverted from the river to the recorded flow at the boundary, and by subtracting all water that is released to the river upstream of the boundary. The construction of a reservoir with the resultant impoundment of runoff greatly increases the amount of water lost to the atmosphere. This increase in evaporation is considered to be a depletion of the natural flow and is charged to the jurisdiction where the loss occurs. Presented below is an example of how evaporation pan data is used for natural flow computations for the Souris River. Pan evaporation and precipitation data are obtained from three meteorological stations in the Souris River Basin. They are located at Weyburn, Estevan, and near Moose Mountain Reservoir. A variable monthly coefficient is applied to convert pan data to lake evaporation. These coefficients are as follows : Ma y 0.65 Jun e 0.70 July Augus t 0.80 September 0.90 October 0.80 The meteorological stations report the net evaporation as water added to or removed from the pan. A negative value indicates water removed from the pan. Gross evaporation is calculated as : Loss in the reservoir is calculated as : gross evaporation = precipitation + net evaporation net loss = [(gross evaporation x coefficient) - precipitation + seepage] x surface area Net reservoir loss is computed on a monthly basis for major reservoirs and on a daily basis for index reservoirs when they are filling and/or spilling. If evaporation pan data is not available, empirical methods must be used. For example, in the Qu'Appelle River Basin, the Water Resources Branch uses Meyer's formula to estimate evaporation. An example is presented below. 28

33 Evaporation data for Lake Diefenbaker is calculated using Meyer's formula : E = C ( u) (e o - e a ) where E is evaporation for month C is Meyer's coefficient u is monthly average wind velocity measured 8 m (25 ft) above the water surface e o - e a is the vapor pressure deficit, where e o is the saturated vapor pressure at the mean surface water temperature, and e a is the vapor pressure in the atmosphere 8 m (25 ft) above the water. A.E.S. collects wind speed, vapor pressure, and water temperature data. The water temperature is used to compute e o. 29

34 8.0 SUMMARY The types of climatological records available for use in streamflow computation have been described in this lesson package. These include data on : precipitation, air temperature, and evaporation collected by the Atmospheric Environment Service. Other sources of climatological data have also been discussed. The techniques for using these data to estimate streamflow during winter and open-water periods have been described in detail through the use of example exercises. With practice, the field officer will become proficient in these techniques. 30

35 9.0 MANUALS AND REFERENCES 9.1 MANUALS Environment Canada (1980a), Manual of Hydrometric Data Computation and Publication Procedures, 5 th ed., Inland Waters Directorate, Water Resources Branch, Ottawa, 33 pp. (1980b), Automated Thermograph Computations, Inland Waters Directorate, Water Resources Branch, Ottawa. (1984), Methods for the Estimation of Hydrometric Data, Inland Waters Directorate, Water Resources Branch, Ottawa, 23 pp. 9.2 REFERENCES Barnes, H.H., and Davidian, J. (1978), Chap. 5, Indirect Methods, in Hydrometry: Principles and Practices, ed. R.W. Herschy, John Wiley and Sons, New York, pp Energy, Mines and Resources Canada (1974), The National Atlas of Canada, The Macmillan Co. of Canada Ltd., Toronto, 254 pp. Environment Canada (1981), Climatological Station Data Catalogue, Atmospheric Environment Service, Ottawa. Environment Canada (1986), Climatic Atlas Canada, Atmospheric Environment Service, Ottawa. Fisheries and Environment Canada (1978), Hydrological Atlas of Canada, Supply and Services Canada, Ottawa. Gray, D.M., ed. (1970), Handbook on the Principles of Hydrology With special emphasis on Canadian conditions, Secretariat, Canadian National Committee for the International Hydrological Decade, Ottawa. Hopkinson, R.F. (1986), Design Wind Study Phase I, Prairie Provinces Water Board, PPWB Report 90, 14 pp. Hoyt, W.G. (1913), The Effects of Ice on Streamflow, Department of the Interior, U.S. Geol. Survey Water Supply Paper 337, 77 pp. Johnson, B.N. (1973), Description and Evaluation of the Method of Determining Natural Flow in the Souris River Basin in Saskatchewan, Water Survey of Canada, Regina, Sask. Kennedy, E.J. (1983), Chapter A13, Book 3, Applications of Hydraulics, in Computation of Continuous Records of Streamflow, U.S. Geol. Survey Techniques Water-Resour. Langbein, W.B., and Iseri, K.T. (n.d.), General Introduction and Hydrologic Definitions, U.S. Geol. Survey Water Supply Paper 1541-A, (reprinted 1983), 29 pp. Linsley, R.K., Kohler, M.A., and Paulhus, J.L.H. (1975), Hydrology for Engineers, McGraw-Hill Series in Water Resources and Environmental Engineering, 2nd ed., McGraw-Hill Book Company, New York. Ontario Ministry of Natural Resources (1984), Water Quantity Resources of Ontario, Toronto, 72 pp. Phillips, D.W. (1982), Handbook on Climate Data Sources of the Atmospheric Environment Service, Canadian Climate Centre, Atmospheric Environment Service, Environment Canada, Downsview, Ont. Prairie Hydrometeorological Centre, Temperature and Evaporation on Lake Diefenbaker, Regina, Sask. Rantz, S.E, et al. (1982), Computation of Discharge, U.S. Geol. Survey Water Supply Paper 2175 (2 vol.), 631 pp. Rosenberg, H.B., and Pentland, R.L. (1966), Accuracy of Winter Streamflow Records, Water Resources Branch, 31

36 Inland Waters Directorate, Environment Canada, reprint of 1966 Eastern Snow Conference 1983, pp Sangal, B.P. (1986), Chap. 11, Estimating Peak Flows, in Encyclopedia of Fluid Mechanics, ed. N.P. Cheremisinoff, Gulf Publishing Company, Houston, pp Schulz, E.F. (1973), Problems in Applied Hydrology, Water Resources Publication, Fort Collins, Colo., 501 pp. Shiau, S.Y., and Steingass, C. (1985), Analysis of Basin Storage and Water Balance with Climatological Estimate of Areal Evapotranspiration Program BSTOR, Water Resources Branch, Inland Waters Directorate, Environment Canada, Ottawa, 61 pp. Snyder, F.F. (1938), Synthetic Unit Graphs, Trans. Amer. Geophys. Union 19: U.S. Department of Agriculture Soil Conservation Service (1972), National Engineering Handbook, Hydrology, Part 4, Washington, D.C., U.S. Govt. Printing Office. U.S. Department of the Interior (1965), Design of Small Dams, Bureau of Reclamation, Water Resources Technical Publication, 3 rd Printing, U.S. Govt. Printing Office, Washington, D.C. 32

37 APPENDIX A: PLOTTING OF DAILY PRECIPITATION AND TEMPERATURE Table A-1: Monthly Meteorological Summaries (January) 33

38 Table A-2. Monthly Meteorological Summaries (February) 34

39 35

40 Table A-3. Monthly Meteorological Summaries (March) 36

41 Table A-4. Monthly Meteorological Summaries (April) 37

42 Table A-5. Monthly Meteorological Summaries (May) 38

43 Table A-6. Monthly Meteorological Summaries (June) 39

44 Table A-7. Monthly Meteorological Summaries (July) 40

45 Table A-8. Monthly Meteorological Summaries (August) 41

46 Table A-9. Monthly Meteorological Summaries (September) 42

47 Table A-10. Monthly Meteorological Summaries (October) 43

48 Table A-11. Monthly Meteorological Summaries (November) 44

49 Table A-12. Monthly Meteorological Summaries (December) 45

50 Table A-13. Daily Water Levels for Gauging Station 46

51 Table A-14. Daily Discharges for Gauging Station 47

52 APPENDIX B: PLOTTING OF DAILY PRECIPITATION AND TEMPERATURE (Tables are the same as Appendix A on the web. Is it a mistake?) Table B-1. Monthly Meteorological Summaries (January) Table B-2. Monthly Meteorological Summaries (February) Table B-3. Monthly Meteorological Summaries (March) Table B-4. Monthly Meteorological Summaries (April) Table B-5. Monthly Meteorological Summaries (May) Table B-6. Monthly Meteorological Summaries (June) Table B-7. Monthly Meteorological Summaries (July) Table B-8. Monthly Meteorological Summaries (August) 48

53 Table B-9. Monthly Meteorological Summaries (September) Table B-10. Monthly Meteorological Summaries (October) Table B-11. Monthly Meteorological Summaries (November) Table B-12. Monthly Meteorological Summaries (December) Table B-13. Daily Water Levels for Gauging Station Table B-14. Daily Discharges for Gauging Station 49

54 THE WATER SURVEY OF CANADA HYDROMETRIC TECHNICIAN CAREER DEVELOPMENT PROGRAM Lesson Package No. 17 International Gauging Station B.N. Johnson Water Resources Branch Environment Canada 2365 Albert Street Regina Saskatchewan Canada S4P 4K1

55 Copyright All rights reserved. Aussi disponible en français

56 TABLE OF CONTENTS 1.0 PURPOSE AND BACKGROUND OBJECTIVES INTRODUCTION DEFINITIONS INTERNATIONAL GAUGING STATION INTERNATIONAL SUPPORT GAUGING STATION SUSPENSION OF INTERNATIONAL GAUGING STATIONS DISCONTINUANCE OF INTERNATIONAL GAUGING STATIONS NATURAL FLOW BOUNDARY WATERS TREATY INTERNATIONAL JOINT COMMISSION INTERNATIONAL ST. CROIX RIVER BOARD OF CONTROL INTERNATIONAL LAKE CHAMPLAIN BOARD OF CONTROL INTERNATIONAL ST. LAWRENCE RIVER BOARD OF CONTROL INTERNATIONAL NIAGARA BOARD OF CONTROL INTERNATIONAL LAKE SUPERIOR BOARD OF CONTROL INTERNATIONAL RAINY LAKE BOARD OF CONTROL INTERNATIONAL LAKE OF THE WOODS BOARD OF CONTROL INTERNATIONAL SOURIS RIVER BOARD OF CONTROL ACCREDITED OFFICERS FOR THE ST. MARY AND MILK RIVERS INTERNATIONAL KOOTENAY LAKE BOARD OF CONTROL INTERNATIONAL COLUMBIA RIVER BOARD OF CONTROL INTERNATIONAL OSOYOOS LAKE BOARD OF CONTROL OPERATION OF INTERNATIONAL GAUGING STATIONS RESPONSIBILITY FOR OWNERSHIP, OPERATION AND MAINTENANCE SCHEDULING OF PROPOSED VISITS FIELD SURVEYS AUTHORIZED DURING GAUGING STATION VISITS MEASUREMENT SYSTEMS REPORTING SYSTEMS Distribution of Checked Original Notes Use of Forms and Formats in Canada and USA BENCH MARKS AND REFERENCE DATUM BORDER CROSSING PERMITS VEHICLES DATA COMPUTATIONS SPECIFIC OPERATIONAL AND COMPUTATIONAL PROCEDURES B.C. AND YUKON ALBERTA iii

57 9.2.1 St. Mary and Milk Rivers SASKATCHEWAN Eastern Tributaries of the Milk River International Stations Operated by the USGS International Stations Operated by the WRB International Support Stations Operated by WRB Priorities Poplar River Bilateral Monitoring Committee Monitoring MANITOBA AND NORTHWESTERN ONTARIO International Stations Operated and Computed by Canada International Stations Operated and Computed by the United States Canadian Stations Required for Support of Canadian International Stations Canadian Stations Required for Support of American International Stations ONTARIO QUEBEC NEW BRUNSWICK International Stations Operated by the USGS International Station Operated by WRB International Support Flow Station Operated by WRB International Support Water Level Stations Operated by WRB SUMMARY REFERENCES...28 iv

58 1.0 PURPOSE AND BACKGROUND This lesson package is part of the essential basic curriculum of the Career Development Program. The material provides an outline of the Boundary Waters Treaty, the function of the International Joint Commission, and the procedures for operating gauging stations and computing data in international basins. 1

59 2.0 OBJECTIVES The objectives of this lesson package are : To provide all technicians with a general overview of the procedures for the operation of gauging stations and data computations in international basins. To provide technicians working in international basins with detailed procedures for the operation of gauging stations and data computations in their specific basins. 2

60 3.0 INTRODUCTION Since the signing of the Boundary Waters Treaty in 1909, the United States and Canada have cooperated in monitoring streamflow and water levels on international waters at locations of mutual concern. The Water Resources Branch has been delegated the responsibility for operating streamflow and water level gauging stations associated with international agreements, treaties, orders or studies. These include : 1. Stations specifically named under the Boundary Waters Treaty and those approved officially as International Gauging Stations. 2. Stations specifically stipulated under International Joint Commission (IJC) orders, or required to support such orders. Such stations may also be required for studies carried out under unilateral or bilateral mechanisms and undertaken in anticipation of the need for formal orders. 3. Stations related to international treaties and agreements which involve waters crossing or forming part of the international boundary. Agreements which specifically stipulate the reaches of streams required to be monitored or special arrangements that need to be made to meet water quantity survey needs are also included. 4. Stations on streams flowing across or forming part of the international boundary for which Canada has determined that monitoring is required for water management purposes. 3

61 4.0 DEFINITIONS The following definitions apply specifically to work in international basins. 4.1 INTERNATIONAL GAUGING STATION The term International Gauging Station is applied to any hydrometric discharge or stage measurement station which has been officially designated as international by the International Joint Commission (IJC). These stations are situated on any boundary water as defined in the Boundary Waters Treaty of 1909 or orders thereof, or any body of water crossing the international boundary between Canada and the United States. These stations provide data in accordance with an international agreement, understanding or other mutually agreed purposes. International Gauging Stations may be operated by water agencies of either country, or jointly. The data must be collected in a mutually satisfactory manner according to the agreed procedures and must be available to users in both countries. The procedures for designating a station as international are contained in the Procedural Guide for International Gauging Stations, pp INTERNATIONAL SUPPORT GAUGING STATION Hydrometric stations are sometimes established to support the purposes of the IJC or the Boundary Waters Treaty. These and other operating stations may provide the data that will assist in making apportionment calculations, or for any other supportive purpose in relation to existing International Gauging Stations. These support stations are also referred to as semi-international gauging stations. These support stations play a vital role in the provision of desirable data, particularly for studies or applications for apportionment, for regulatory works, and for monitoring future potential applications. Regardless of their supportive international significance, if these stations have not been designated as International Gauging Stations, there is no absolute requirement on either side to follow the procedural guide that governs inspection visits, approval and publication of data, or any other aspect of the official international designation. The responsible parties at the working level, however, may make informal local arrangements regarding inspection visits, and the collection, use and publication of the data. 4.3 SUSPENSION OF INTERNATIONAL GAUGING STATIONS The suspension of an International Gauging Station involves the temporary discontinuance of all international activities at that site by the water agencies of both countries. The station, however, may continue to be operated by the agency of the country in which it is located. Upon mutual consent, it may be brought back to full operation at some future date according to established international procedures. The procedures for suspending or reinstating a suspended station to international status are contained in the Procedural Guide for International Gauging Stations, p.5. Administratively, it is much easier to suspend an international gauging station than it is to discontinue the station and later re-establish it. 4.4 DISCONTINUANCE OF INTERNATIONAL GAUGING STATIONS When the joint collection of data from an International Gauging Station is no longer required, the responsible officers may agree mutually to request termination of the international status of the station. 4

62 The procedures for discontinuing an international station are contained in the Procedural Guide for International Gauging Stations, p NATURAL FLOW Natural flow is defined as the quantity of water which would naturally flow in any watercourse if the flow had not been affected by human interference or human intervention. 5

63 5.0 BOUNDARY WATERS TREATY When early development of agriculture extended into the semi-arid areas of western Canada and the United States, it was soon evident that irrigation was essential to the success of the industry. The Governments of both countries undertook studies to determine what water supplies were available and the lands upon which they could be economically used. In the 1890s, irrigation began in Montana and Alberta with the diversion of the waters of the St. Mary and Milk rivers. Both are international rivers. Disputes over the use of the limited water supply quickly developed between the two countries. The International Waterways Commission was appointed by the United States and Great Britain in 1903 to investigate and report upon the conditions and uses of the water adjacent to the boundary between the United States and Canada. The dispute concerning the use of water originating from the St. Mary and Milk rivers was brought before the Commission. However, no action could be taken at the time since Congress had limited the jurisdiction of the United States section of the Commission to waters whose natural outlet was the St. Lawrence River. By 1907, the International Waterways Commission had begun to draft a treaty between Great Britain and the United States. This treaty was to cover the use of boundary waters between the United States and Canada and it established a joint commission to administer the treaty. The Boundary Waters Treaty resulted from these negotiations in The following is a summary of the articles contained in the Boundary Waters Treaty. The complete text of the treaty can be found in Appendix 1 of the Procedural Guide for International Gauging Stations. Article I The navigation of all navigable boundary waters shall forever continue free and open for the purposes of commerce. This right shall also extend to the waters of Lake Michigan and all canals (existing or future) connecting boundary waters. Article II Each country, state or province as the case may be has exclusive jurisdiction and control of all waters on its own side of the line. However, any interference with or diversion of waters that result in any injury on the other side of the boundary is subject to litigation. Article III The International Joint Commission must approve any future uses, obstructions or diversions of boundary waters that affect the natural level or flow of boundary waters. This does not apply to the ordinary use of water for domestic and sanitary purposes, nor to works that benefit commerce or navigation, provided the works do not materially affect the level or flow of the boundary waters. Article IV The International Joint Commission must approve construction or maintenance of works in waters flowing from boundary waters which raise the natural level of waters on the other side of the boundary. Boundary waters and waters flowing across the boundary shall not be polluted to the injury of health or property on the other. Article V It is expedient to limit the diversion of waters from the Niagara River so that the level of Lake Erie and the flow of the stream shall not be appreciably affected. 6

64 Note The diversion of the Niagara River is covered by the Canada United States Treaty of February 27, Article VI The article governs the matter of measurement and apportionment of the waters of the St. Mary and Milk Rivers and their tributaries in the State of Montana and the Provinces of Alberta and Saskatchewan. Note The 1921 Order of the International Joint Commission Respecting the St. Mary Milk Rivers provides further requirements for measurement and apportionment. The Order can be found in Appendix 5 of the Procedural Guide for International Gauging Stations. Article VII This article provides for the establishment and maintenance of the International Joint Commission. Article VIII This article describes the powers and jurisdiction of the International Joint Commission. Article IX This article makes provision for either country to refer questions involving the rights, obligations or interest of either country along the boundary to the International Joint Commission. The Commission is authorized to examine into and report upon the facts of question together with such conclusions and recommendations as may be appropriate. Article X This article makes provision for Canada and the United States to jointly refer questions involving the rights, obligations or interests of either country to the International Joint Commission for a decision. Article XI Duplicate originals of all decisions rendered and joint reports made by the Commission shall be transmitted to and filed with the Secretary of State of the United States and the Governor General of Canada. Article XII This article deals with several administrative items of the Commission including the appointment and payment of commissioners and secretaries, location and timing of meetings, rules of procedure and powers to administer oaths. Article XIII Any special agreements mentioned in the articles refer to direct agreements and any mutual agreement expressed by concurrent or reciprocal legislation on the part of both countries. Article XIV This article provides for the ratification and termination of the treaty. It may be terminated on twelve month's written notice by either country. 7

65 6.0 INTERNATIONAL JOINT COMMISSION The information in this section was extracted from International Joint Commission Activities Report, The International Joint Commission was established under the Boundary Waters Treaty of The IJC consists of three Canadian and three United States Commissioners, with a co-chairman from each country. The Commission has headquarters in Ottawa, Ontario and in Washington, D.C., each with a secretary as well as a small advisory and support staff. Another office, with both Canadian and U.S. staff, is situated in Windsor, Ontario. It assists the Commission with its responsibilities under the Great Lakes Water Quality Agreement. The Canadian members of the Commission are appointed by the Governor-in-Council of Canada. The United States members are appointed by the President with the advice and consent of the U.S. Senate. The Commission conducts its business as a single unitary body. The Commissioners serve, not as national delegations representing their respective governments, but as a collegial body seeking common impartial solutions in the interest of both countries. The two co-chairmen are full-time, while the other Commissioners serve part-time. Traditionally the Commission's activities fall into two broad categories; Applications and References. I. Applications The Commission considers and authorizes, with such conditions as may be required, Applications for obstructions, uses or diversions of water which affect the natural level or flow of boundary water on the other side of the international boundary or raise the level of transboundary rivers at the boundary. II. References The Commission investigates questions or matters of difference along the common frontier when requested by the governments of Canada and the United States. In conducting these References, the Commission develops a commonly accepted factual basis and then recommends appropriate action to the Governments. The Commission has no implementing powers; the Governments must decide whether to accept or act upon the Commission's recommendations. In addition, the Commission has ongoing responsibilities with respect to Applications and References. It usually monitors compliance with the terms and conditions set forth in its Orders of Approval which follow from Applications. Also, when requested by the two Governments, the Commission monitors and coordinates actions or programs resulting from governmental acceptance of recommendations made by the Commission. In recent years, the Commission has acted as a mediator and catalyst in resolving some long-standing resource use conflicts under its jurisdiction. The Boundary Waters Treaty also permits the Governments to refer any issues to the Commission for binding decision. Although this provision has never been used, the Commission's responsibilities can be extended beyond its normal role of producing reports and recommendations. The technical studies and the field work required by the Commission to carry out its functions are performed by binational boards of experts appointed by the IJC. These boards consist of engineers, scientists and other experts, many of them public servants, whose services are supported by their agencies. Reports from these boards to the Commission are usually released to the public. The Water Resources Branch is directly involved in supporting the activities of several IJC Boards. These are discussed here. 8

66 6.1 INTERNATIONAL ST. CROIX RIVER BOARD OF CONTROL Dockets : 10, 11, 18, 28, 32, 80, 109 This Board was initially established in 1915 to supervise construction and operation of a dam and power canal at Grand Falls. The Board's duties were expanded to include other matters in the region concerning water levels, flows and fishways. The Board was also responsible for the St. Croix River fishways, and dams at Milltown and Vanceboro. 6.2 INTERNATIONAL LAKE CHAMPLAIN BOARD OF CONTROL Docket : 38 The International Joint Commission established the International Lake Champlain Board of Control and charged it with the responsibility of ensuring compliance with the provisions of the Order of Approval dated June 10, 1937, insofar as they relate to the regulation of the levels of Lake Champlain. Members of the Board are appointed by the Governments. 6.3 INTERNATIONAL ST. LAWRENCE RIVER BOARD OF CONTROL Dockets : 68, 88, 100 The Board was established in November 1953 pursuant to the Commission's 1952 Order. The Order granted approval to Ontario Hydro and the Power Authority of New York State for the construction, maintenance and operation of works to develop power in the International Rapids Section of the St. Lawrence River. The Board's duties include implementing the Commission's instructions relating to water levels and regulating the discharge of water from Lake Ontario. The Board also regulates the flow of water through the International Rapids section of the St. Lawrence River. 6.4 INTERNATIONAL NIAGARA BOARD OF CONTROL Dockets : 64, 75, 78, 79 The Board was established in 1953 to review and approve the design and construction of remedial works at Niagara Falls and to exercise control over the works, including the Grass Island pool control structure. Later, the Board's responsibilities were expanded to include remedial works extension, shoal removal in the river, and the annual installation and removal of the ice boom at the head of the Niagara River. 6.5 INTERNATIONAL LAKE SUPERIOR BOARD OF CONTROL Dockets : 6, 8 In 1914, the Commission approved applications by Michigan Power Co. in the U.S. and Algoma Steel Corporation in Canada to divert water for power purposes and to construct a control structure across the St. Mary's River. The Board was established to supervise construction of the control structure (compensating works) and to assume responsibility for regulating Lake Superior levels by implementing plans approved by the IJC governing the discharge of water through the compensating works and the power canals. 6.6 INTERNATIONAL RAINY LAKE BOARD OF CONTROL Dockets : 40, 50 9

67 Established in 1941 pursuant to the Rainy Lake Convention (1940), the Board now supervises the operation of the International Falls Fort Francis Dam on the Rainy River and Kettle Falls Dam on Namakan Lake to regulate the levels of Rainy and Namakan Lakes according to regulation plans approved by the Commission. 6.7 INTERNATIONAL LAKE OF THE WOODS BOARD OF CONTROL Docket : 3 The Lake of the Woods Convention (1925) provided for the establishment of a Board with the responsibility for regulating the rate of water discharge from Lake of the Woods when lake levels either exceeded or fell below certain prescribed levels. Although the Board is appointed by both Canadian and U.S. Governments, it also reports to the IJC. 6.8 INTERNATIONAL SOURIS RIVER BOARD OF CONTROL Docket : 41 The Board was established in 1959 to ensure compliance with certain interim measures recommended by the Commission and approved by Canadian and U.S. Governments. The Board outlines the rights that Saskatchewan, North Dakota and Manitoba have regarding the use of waters in the Souris River basin, as well as the rights of Saskatchewan and North Dakota regarding the waters of Long Creek. 6.9 ACCREDITED OFFICERS FOR THE ST. MARY AND MILK RIVERS Docket : 9 Article VI of the 1909 Boundary Waters Treaty provides for the appointment of officers in their respective countries by the United States and Canada. These officers, under IJC direction, serve the purpose of jointly carrying out the diversion or apportionment of waters originating from the St. Mary and Milk rivers as specified in the Treaty. An order amplifying Article VI was issued by the Commission in INTERNATIONAL KOOTENAY LAKE BOARD OF CONTROL Dockets : 23, 29, 34, 39, 42, 48, 62, 70, 90 In 1938, the Commission issued an Order of Approval for the construction of works to regulate Kootenay Lake, and for the establishment of a Board to supervise the construction and operation of the works. The Board is also responsible for the continuing regulation of Kootenay and Duck Lakes INTERNATIONAL COLUMBIA RIVER BOARD OF CONTROL Docket : 44 The Board was established under the Commission's 1941 Order which approved the construction of the Grand Coulee Dam on the Columbia River. The Board was directed to study how the operation of the Grand Coulee Dam and Franklin D. Roosevelt Lake would affect the water levels on the Columbia River in Canada. The Board was also to ensure compliance with the 1941 Order. 10

68 6.12 INTERNATIONAL OSOYOOS LAKE BOARD OF CONTROL Dockets : 49, 108 A Commission order, issued in 1946, specified that the Zosel Dam at the outlet of Osoyoos Lake be altered and operated so that pool elevations above the dam did not exceed certain prescribed levels. The International Osoyoos Lake Board of Control was established pursuant to this order and was given the responsibility to ensure that the Zosel Dam is operated according to the provisions of the order. An application by the State of Washington was approved by the IJC in 1982 for new control works. In October 1985, the Commission issued a Supplementary Order to accommodate certain changes in the design of the control works. 11

69 7.0 OPERATION OF INTERNATIONAL GAUGING STATIONS The information in sections 7.1 to 7.7 was obtained from the Procedural Guide for International Gauging Stations and covers, in general terms, the operation of international gauging stations. Procedures that are unique to individual provinces or basins are contained in Section RESPONSIBILITY FOR OWNERSHIP, OPERATION AND MAINTENANCE As a general rule, the location of the gauging station shelter that houses the water level recorder determines whether the station is operated by the Canadian or the United States agency. Normally, the operating agency originates from the country where the principal gauging structure is located. The gauging station, complete with recording and auxiliary equipment, is supplied, built, owned and maintained by the host country. The operating agency of the host country is also responsible for paying land leases and salaries of gauging station attendants. The water agency of the country in which the structures are located must arrange to lease the property on which the cableway tower is erected or where other parts of the station are situated. When facilities of an International Gauging Station are located on both sides of the boundary, property rights in both countries must be respected. Public liability is the responsibility of the agency in charge of the physical structures of the gauging station. In the case of cableways, the responsibility for public liability lies with the country on whose territory the supporting tower has been erected. With regard to employee liability, each country is responsible for its own personnel. Sometimes, for expediency, one water agency installs recording gauges or auxiliary station equipment in the other country's gauging station shelter or at the gauging station site. This equipment remains the property of the water agency in the country which supplied it. Field officers of either country may use this equipment while operating and maintaining the International Gauging Station. If a representative of the appropriate District or Regional Office of the other country visits a station and finds that it requires minor adjustments or repairs that can be made during the visit, the representative should make the repairs and report what was done to the appropriate office later. Major structural repairs or changes to the basic recording system are not to be performed until the responsible operating agency has been consulted. Emergency repairs, however, may be made to maintain the continuity of records at the station. A report on such repairs must be made as quickly as possible to the responsible operating agency. 7.2 SCHEDULING OF PROPOSED VISITS Wherever possible, representatives of the appropriate District or Regional Office of the other country should visit the International Gauging Stations several times annually. Where the respective District or Regional Chiefs consider it feasible, schedules of proposed visits should be established for each water-year or calendar-year. This provides more economical operations by eliminating duplication of visits at short intervals. Where possible, the appropriate officers of both agencies should arrange for the field officers from the agency of the other country to make a minimum of three visits annually to each International Gauging Station. 7.3 FIELD SURVEYS AUTHORIZED DURING GAUGING STATION VISITS The field work performed by a field officer at an International Gauging Station follows the prescribed routine procedure customarily used in the country of the visiting officer. Level checks should normally be carried out as part of a regular station inspection or as agreed upon by the two agencies. The field officers of either agency should make streamflow measurements on each visit unless they are prevented by conditions or other commitments. 12

70 The offices of the District Chief and the Regional Chief usually arrange details of field survey work to be performed at International Gauging Stations. Some of the routine operations performed at such stations are: 1. Level checks for manual gauges (non-recording) and recording gauges 2. Verification of analog recorders 3. Routine procedural checks for servo-manometers, digital punched paper tape recorders, and telemetry equipment 4. Discharge measurements 5. Water quality sampling and sediment data measurements 6. Water and air temperature observations 7. Routine maintenance checks including minor repairs and adjustments to recording devices 8. Replacement of faulty recorders or system component parts. When inspecting gauging stations equipped with manual devices and instrumentation, it is customary for the field officer to follow the field procedures and use the forms commonly prescribed by the field officer's country. Some International Gauging Stations are equipped with specialized equipment such as data collection platforms (DCPs), data telemetry systems, data loggers, encoders and similar measurement equipment. For those stations, the field offices in each country should jointly determine the procedures for inspection, maintenance and repair of the sophisticated equipment. 7.4 MEASUREMENT SYSTEMS Canada has converted to the International System of Units (SI units) for hydrometric surveys. Field officers usually carry out field inspections of instruments, level checks and flow measurements using the measuring equipment and units used in their own country. The original field notes should not be altered, and should be presented in the units used for recording observations. Use the conversion factors shown in Table 1 to change from one system of units to the other. Where conversions are not practical, such as observations of feed pressure on a servo-manometer pressure regulator, record the observations in the units shown on the instrument. The following list of measurement conversions presents the relationship between imperial (yard/pound) units and the International System of Units (SI) (metric), and includes other convenient equivalents of measure. (Applicable listings conform to the Canadian Metric Practice Guide CAN3-Z ). 13

71 Table 1. Conversion Factors 1 inch = 2.54 cm (centimetres) 1 centimetre = 0, po (pouce) 1 foot = m (metres) 1 metre = 3, pi (pieds) 1 yard = m (metres) 1 metre = 1, verge 1 statute mile = km (kilometres) 1 kilometre = 0, mi (mille) 1 square mile = km² (square kilometres) 1 square kilometre = 0, mi² (milles carrés) 1 hectare = m² (square metres) 1 square kilometre = 100 ha (hectares) 1 acre = ha (hectares) 1 hectare = 2, acres 1 acre-foot = dam³ (cubic decametres) 1 cubic decametre = 0, acre-pied 1 cubic foot per second = m³/s (cubic metre per second) 1 cubic metre per second = 35,315 pi³/s (pieds cubes par seconde) 1 imperial gallon = L (litres) 1 imperial gallon = U.S. gallons 1 U.S. gallon = imperial gallons 1 U.S. gallon = L (litres) 1 litre = imperial gallons 1 litre = U.S. gallons 1 imperial gallon per minute = L/s (litres per second) 1 U.S. gallon per minute = L/s (litres per second) 1 million imperial = m³/d (cubic metres per day) gallons/day 1 million U.S. gallons/day = m³/d (cubic metres per day) 1 ounce = g (grams) 1 gram = oz. (ounces) 1 pound = Kg (kilograms) 1 kilogram = lbs (pounds) degrees Celsius = 5/9 (degrees Fahrenheit - 32) degrees Fahrenheit = 9/5 (degrees Celsius + 32) 14

72 15

73 7.5 REPORTING SYSTEMS Mutually acceptable arrangements can be made between the District and the Regional Offices for transmitting the results of the gauging station visits. However, some basic guidelines are suggested here Distribution of Checked Original Notes Forward the checked original notes for any level check or flow measurement at an International Gauging Station to the District or Regional Office responsible for the computation of the station record. When the original notes are to be sent to an office in the other country, keep copies of the level notes or front sheet and the discharge measurement notes. These may be used as the official records for the station. Retain the original discharge measurement notes indefinitely. Field data contained on microfilm or microfiche as part of District and Regional Office files are equally acceptable as official station data. If either country institutes a policy of microfilming field notes and destroying originals, all original field notes should be returned to the other country Use of Forms and Formats in Canada and USA When the U.S. is the principal operator of a station, a Canadian field officer may use Canadian forms to record observations and inspections of station equipment, even if the Canadian forms differ from the U.S. forms. Similarly when Canada is the principal station operator, U.S. field officers may use U.S. forms. The original or copies become a part of the official record of the gauging station. Distribution of original inspection notes for different types of gauges and retransmission devices shall be those in common usage in the country of the visiting field officer. 7.6 BENCH MARKS AND REFERENCE DATUM The installation of bench marks at an International Gauging Station principally operated by the U.S. should follow the American standard construction and marking procedure. If Canada is the principal operator, use Canadian procedures. In Canada, the national reference datum is the Geodetic Survey of Canada Datum (year of adjustment). In the U.S.A., the national reference datum is the National Geodetic Vertical Datum of The reference datum on the Great Lakes is the International Great Lakes Datum (IGLD), (1959). At each International Gauging Station, the principal permanent bench mark should be tied to the national network datum or a well-documented local datum, such as the IGLD whenever possible. Wherever feasible, reference lines should be established between the principal permanent bench mark at an International Gauging Station and the closest national reference datum bench mark on the other side of the international boundary. This procedure will enable the establishment of a relationship between the two national reference datums at the boundary in the vicinity of the International Gauging Station. Establishment of the relationship may prove useful in joint studies using the data collected at that station. 16

74 7.7 BORDER CROSSING PERMITS From time to time, strict immigration regulations for ports of entry at the International Boundary may cause problems and delays when qualified field officers try to cross the border to visit an International Gauging Station in the other country. To expedite the border crossing by field officers of the United States Geological Survey (USGS), Government of Canada officials issue bearer letters which are presented to Canadian Immigration officers at the ports of entry. Canadian immigration officers are instructed to recognize these letters of introduction as border crossing permits. The letter permits U.S. field officers to enter Canada for the purpose of conducting field and inspection trips to International Gauging Stations in the context of the Boundary Waters Treaty of Each November, the Regional Hydrologist of the USGS writes to the Director General, Inland Waters Directorate, indicating which field officers require border crossing permits for the coming calendar year. 7.8 VEHICLES Canadian Government vehicles that travel to the United States must carry special insurance. The driver must use a credit card issued by a petroleum company because the Government of Canada credit card will not be accepted in the United States. 17

75 8.0 DATA COMPUTATIONS The following general information comes from the Procedural Guide for International Gauging Stations. Procedures unique to individual provinces or basins appear in Section 9.0 of this lesson package. Each District or Regional Office should complete the initial office computation of the records for each International Gauging Station in its District or Region by following the standard procedures established for regular stations. Data computations are performed by making appropriate use of the data provided by the office involved in field activities at that station. Where this procedure is not convenient, make mutually acceptable adjustments with the appropriate officers. Original office computations may be made by utilizing comparison data available from hydrologically compatible stations located on either side of the border. Exchange such supportive data with the offices concerned. After the initial computations are performed, the District and Regional Chiefs or their designated field officers undertake a joint review and approval of the records. The joint review may be done at a meeting or by correspondence. Personnel of the office verifying the initial data computations from the originating office, are entitled to verify all steps in the computation procedure, including comparisons with hydrologically compatible stations on either side of the border. Since Canada and the United States perform computations differently, the officers must reach mutual agreement on the final listing of data which is to appear in the annual surface water data publications. Original computations should be maintained in the units of the measuring system commonly used in each country. After the joint review of records either by visit or by correspondence, the District and Regional Chiefs, or their designated field officers, shall give their joint approval to the record computations and sign the final listing of the data to be published. 18

76 9.0 SPECIFIC OPERATIONAL AND COMPUTATIONAL PROCEDURES Sections 7.0 and 8.0 described the general procedures and responsibilities for the operation of gauging stations in international basins. They also outlined methods used for the computation and approval of hydrometric data. This section describes specific procedures for individual Water Resources Branch (WRB) regions or basins, and provides appropriate references. 9.1 B.C. AND YUKON No specific procedures are required. 9.2 ALBERTA St. Mary and Milk Rivers The following procedures, outlined in a memo from G.H. Morton, Regional Chief, WRB, Calgary dated , have been accepted by the Field Representatives. 1. Within two weeks of getting a measurement at an International Gauging Station, forward the checked original notes for any visits or any flow measurements to the District office responsible for that station. 2. Keep a copy of the cover sheet of the notes. 3. Send a copy of the front sheet for checked measurements to the District office not responsible for the station, within two weeks of obtaining the measurement. 4. Both countries must keep original discharge measurements indefinitely. 5. If either country institutes a policy of microfilming measurements and destroying originals, then all discharge measurements may be returned to the country which made the measurement. 9.3 SASKATCHEWAN Eastern Tributaries of the Milk River These guidelines outline the priorities of hydrometric computations, list the data to be exchanged between the Water Resources Branch (WRB) and the United States Geological Survey (USGS) and describe the sequence for the procedures International Stations Operated by the USGS Send all original data including charts, measurements and level notes to the USGS as soon as practicable after the data has been retrieved from the field. Retain a copy for the WRB files. If a chart is pulled by WRB, WRB computes it manually, a. makes a print for themselves, and b. sends the original to the USGS for checking. If the USGS pulls a chart, they will compute it manually, and c. send WRB a print for checking, or 19

77 d. send WRB the original for checking. The WRB makes a print and the original is returned to the USGS. The USGS will send the WRB prints of their computation forms for quality checking. The final annual listings in The International System of Units (SI) are generated by WRB to be signed and included in the report to the IJC. These listings are generated from the USGS Imperial Unit listings and the MANUAL program International Stations Operated by the WRB Copies of all forms used in the computations are sent to the USGS for quality checking. Round-trip memos should be attached for confirmation purposes. When data has been approved by memo, the 12 month/page listing and final output is obtained. The annual listing is signed approved by the District/Regional Chiefs at the annual St. Mary Milk River Conference. The final output is duplicated and put on tape for the USGS. Note Final annual listings are to be letter quality prints in duplicate International Support Stations Operated by WRB Stations that do not warrant international classification, but are used in the natural flow computations, are computed as normal WRB stations. As they do not go to the USGS for checking, they are second in priority for computing. The USGS gets a copy of the final 12 month/page listing for flow and water level stations and a copy of water level hydrographs that have estimated periods Priorities March is the deadline set by the International Joint Commission for submission of the St. Mary Milk River Report. Therefore the following priorities in the order of computation must be respected. 1. First, perform the computations for the International Stations used in the natural flow computations and send them to the USGS for quality checking. 2. Then compute the non-division stations. 3. Mail the data for all international stations before December 15 because the postal service slows down considerably just before Christmas. After December 15, send all correspondence and records by courier. Many international stations are irrigation canals and most irrigation ends by August 15. In these cases, begin the final computations in early September. If a new or extended stage discharge curve is developed for a station, send that curve to the USGS for checking as soon as possible. 20

78 The following table (Table 2) lists all stations and the order of priority for computation. Table 2. Priority of Stations for Computation Lodge Creek Basin Priority 11AB089 Altawan Reservoir near Govenlock * 1 11AB083 Lodge Creek below McRae Creek at International Boundary * (USGS) 1 11AB060 Spangler Ditch near Govenlock * 1 11AB094 Bare Creek Reservoir near Elkwater 2 11AB097 Cressday Reservoir near Cressday 2 11AB092 Greasewood Reservoir near Elkwater 2 11AB098 Jaydot Reservoir near Jaydot 2 11AB104 Massy Reservoir near Elkwater 2 11AB091 Michel Reservoir near Elkwater 2 11AB103 Squaw Coulee near Willow Creek 2 11AB082 Lodge Creek near Alberta Boundary 3 Middle Creek Sub-Basin 11AB008 Middle Creek above Lodge Creek * 1 11AB001 Middle Creek below Middle Creek Reservoir * 1 11AB108 Middle Creek near Govenlock 1 11AB009 Middle Creek near Saskatchewan Boundary * 1 11AB080 Middle Creek Reservoir * (required for contents only) 2 11AB114 Middle Creek Reservoir Bedford Outlet 2 11AB115 Middle Creek Reservoir Flood Spillway 2 11AB099 Mitchell Reservoir near Elkwater 2 Battle Creek Basin 11AB027 Battle Creek at International Boundary * (USGS) 1 11AB078 Cypress Lake West Inflow Canal * 1 11AB085 Cypress Lake West Inflow Canal Drain * 1 11AB077 Cypress Lake West Outflow Canal * 1 11AB102 Gaff Ditch near Merryflat * 1 11AB075 Lyons Creek at International Boundary * (USGS) 1 11AB044 McKinnon Ditch near Consul * 1 11AB018 Nashlyn Canal near Consul * 1 11AB058 Richardson Ditch near Consul * 1 11AB084 Vidora Ditch near Consul * 1 11AB095 Adams Lake 2 11AB101 Battle Creek below Nashlyn Project 2 11AB118 Battle Creek below Wilson's Weir 2 11AB096 Battle Creek near Consul 2 21

79 11AB090 Reesor Reservoir near Elkwater 2 11AB020 Shepherd Ditch near Consul 2 11AB117 Battle Creek at Alberta Boundary 3 Frenchman River Basin 11AC064 Belanger Creek Diversion to Cypress Lake * 1 11AC037 Cypress Lake * 1 11AC060 Cypress Lake East Outflow Canal * 1 11AC052 Eastend Canal near Eastend * 1 11AC055 Eastend Reservoir * 1 11AC041 Frenchman River at International Boundary * (USGS) 1 11AC001 Frenchman River below Eastend Reservoir * (non-division) 1 11AC063 Huff Lake * 1 11AC065 Huff Lake Gravity Canal * 1 11AC066 Huff Lake Pumping Canal * 1 11AC056 Newton Lake * 1 11AC054 Newton Lake Main Canal * 1 11AE009 Rock Creek below Horse Creek near International Boundary * (USGS) 1 11AC062 Frenchman River below Newton Lake * (non-division) 2 11AC068 Val Marie Pump No AC025 Denniel Creek near Val Marie 3 * International Gauging Station Poplar River Bilateral Monitoring Committee On September 23, 1980, the Governments of Canada and the United States agreed to a Cooperative Monitoring Arrangement. The parties agreed to exchange data and to determine significant changes in water quality, water quantity, ground water, and air quality resulting from the operation of the Saskatchewan Power Corporation's coal-fired thermal generating station. The arrangement also involves the preparation of an annual report to both governments. A binational committee, called the Poplar River Bilateral Monitoring Committee, was established to carry out the responsibilities under the arrangement. One of the responsibilities of the committee is the quarterly exchange of data. The WRB has the responsibility to provide hydrometric data for the following stations : 11AE003 East Poplar River at the International Boundary 11AE014 East Poplar River above Cookson Reservoir 11AE013 Cookson Reservoir near Coronach 11AE015 Girard Creek near Coronach. The data must be computed within thirty days of the end of the quarter. 22

80 Monitoring The WRB informs the Saskatchewan Water Corporation when the flows in the East Poplar River at the International Boundary are less than those required under the recommended apportionment agreement. The required discharge on the East Poplar at the International Boundary is linked to the total natural flow in the Middle Poplar. This flow is determined below the confluence of Goose Creek during the most recent spring period, from March 1 st to May 31. The recommendations are as follows : Table 3. Natural Flow and Minimum Releases from Cookson Reservoir If the total natural flow in the Middle Poplar during : Then the Minimum Discharge in the East Poplar should be during : March 1 May 31 June 1 August 31 September 1 May 31 < 4690 dam³ m³/s m³/s 4690 à 9250 dam³ m³/s m³/s > 9250 dam³ m³/s m³/s To ensure that the Saskatchewan Water Corporation receives the information required for the effective operation of Cookson Reservoir, all discharge measurements and gauge corrections obtained by the WRB or the USGS shall be transmitted directly by telephone to the Saskatchewan Water River Forecast Centre. 9.4 MANITOBA AND NORTHWESTERN ONTARIO The data requirements and deadlines for the stations that are part of the international station program in the district differ from those of the regular hydrometric program. These differences are due to the approval process that the international stations undergo and to the difference in the computation years. The WRB computes its results on the basis of the calendar year while the Water Resources Division of the USGS bases its data on the Water Year of October 1 st to September 30. The District requirements, which deal more with the presentation of data than computation, are outlined in the following four sections. The information applies to the stations listed International Stations Operated and Computed by Canada These stations are operated and computed as part of the regular hydrometric program, but with a few differences. Any water levels or measurements taken by visiting USGS personnel are to be treated in the same fashion as the data obtained by visiting WRB staff. Use the data in any computations. By late January, complete the computations of daily discharges or water levels and send copies to the USGS office responsible. The approval meeting with the USGS representatives will take place in February to enable them to meet their publication deadline. 23

81 By that time, have the following items ready : Summary of Discharge Measurements. Type the R56, including the USGS visits, in the proper chronological order. 1. Daily Discharges i. An original and one copy of the computer printout (12 month/page) with labelled lines for signatures. ii. A copy of the previous year's printout. 2. Daily Water Levels To be treated in the same way as the daily discharges except that signatures are needed only for water level stations. 3. Hydrographs i. Two copies of the stage and discharge computer plots. ii. An original and copy of form R139 or R139A. Include hydrographs for October, November and December of the previous year. 4. Charts Copies of recorder charts for the calendar year. 5. Station Analysis A typed original and one copy of a complete form R242 with provision for signatures. 6. Stage Discharge i. An original and duplicate of computer printout stagedischarge table. ii. A curve sheet available for inspection. 7. Station Description One copy of an up-to-date district form. 8. Current Datum One copy for the current year. 9. Bench Mark History One copy of the most recent update. 10. Water Year i. Type on the district forms : a. valid daily discharges b. valid instantaneous discharges c. valid maximum levels d. valid minimum levels 24

82 ii. Attach a reduced form to the listing which gives 12 months on one page International Stations Operated and Computed by the United States These stations, generally located within the U.S., are operated and visited by the USGS. Level checks and measurements are taken as required. A minimum of two trips are made to USGS stations. Close contact between the field offices helps to ensure that the field visits are conducted between the regular visits of USGS staff. It also helps to coordinate field visits during periods when flow measurements are possible at the discharge stations. Within a few days of each visit, send the original field note to the USGS office responsible and retain a copy for WRB files. For the February approval meeting, make available a typed R56 of such visits Canadian Stations Required for Support of Canadian International Stations The data from these stations is needed at the time of the approval meeting in February to assist in the checking process. The type of data required varies; usually an R56, daily discharges (or water levels) and the complete R139 hydrograph are needed Canadian Stations Required for Support of American International Stations Data from these WRB hydrometric stations is used as a computation aid by the USGS and as a check during the approval meeting. Each October, provide the USGS District with daily discharges or water levels for the previous 12 months. Although the discharges are provisional, ensure that they are as accurate as possible, especially for the backwater period. Make available the work sheets, especially the R139A, for use at the February approval meeting. 9.5 ONTARIO There are no specific procedures required. 9.6 QUEBEC There are no specific procedures required. 9.7 NEW BRUNSWICK International Stations Operated by the USGS 01AD002 Saint John River at Fort Kent 01AE001 Fish River near Fort Kent 01AR004 St. Croix River at Vanceboro 01AR005 St. Croix River at Baring. 1. Send original data including discharge measurements, level notes and station inspection forms sent to the USGS in Augusta, Maine as soon as practicable after the data has been retrieved from the field. 2. Retain a copy for the WRB files. 3. On a regular basis, forward copies of any other data that may be of assistance in calculating flows under ice conditions, such as the plant flows furnished by the New Brunswick Electric Power Commission. 25

83 For the two international stations on the St. Croix River, at Vanceboro and at Baring, the USGS furnishes flows by the end of January. This flow data is included in the annual report for the International St. Croix River Board of Control. Computation for the St. John River at Fort Kent (01AD00Z) and Fish River near Fort Kent (01AE001) must be completed by mid-february, when the data for all four stations is jointly reviewed by representatives of the USGS and WRB International Station Operated by WRB 01AD003 St. Francis River at Outlet of Glasier Lake. Forward prints of discharge measurements, level notes and station inspection forms to the USGS. Original field notes are received from the USGS. During February, the data is jointly reviewed by the two agencies and the USGS is given a copy of the approved 12 month/page listing International Support Flow Station Operated by WRB 01AR011 Forest City Stream below Forest City Dam. This station is used to monitor flows for the International St. Croix River Board of Control. It is computed as a normal WRB station and is not visited by staff of the USGS. The data is not included in the joint review of international stations International Support Water Level Stations Operated by WRB 01AR009 Grand Lake at Forest City 01AR013 Grand Falls Flowage at Grand Falls 01AR010 Spednic Lake at St. Croix. The above stations are used to monitor reservoir levels for the International St. Croix River Board of Control and are not visited by staff of the USGS. The data is not included in the joint review of international stations. 26

84 10.0 SUMMARY I. This lesson package has presented a general overview of the procedures established for the operation of gauging stations in international basins. Data computation procedures have also been discussed in general terms. II. This lesson package must be supplemented by specific regional training for all technicians who have been assigned field areas in international basins. 27

85 11.0 REFERENCES 1. Huberman, S., Slater, J.E. and Condes, A. (1985), Procedural Guide for International Gauging Stations on Boundary Waters Between Canada and the United States of America. 1 st Edition, Department of Environment, Ottawa, Canada, Report No. IWD-HQ-WRB-PG-85-1, United States Geological Survey, Reston, Virginia, Open File Report International Joint Commission (1985), International Joint Commission Activities. Report, Ottawa. 28

86 THE WATER SURVEY OF CANADA HYDROMETRIC TECHNICIAN CAREER DEVELOPMENT PROGRAM Lesson Package No. 18 Stage Discharge Relation J. Anderson Water Survey of Canada Environment Canada 854, 222-4th Ave. S.E. Calgary, Alberta Canada T2G 4X3

87 Copyright All rights reserved. Aussi disponible en français

88 TABLE OF CONTENTS 1.0 PURPOSE AND BACKGROUND OBJECTIVES STAGE DISCHARGE CURVES CURVE PLOTTING DETERMINATION OF ZERO FLOW CURVE EXTENSION CURVE LABELLING STAGE DISCHARGE CURVES USING COMPUTER SOFTWARE TOOLS Filing Discharge Measurements STAGE DISCHARGE TABLES STAGE DISCHARGE TABLE USING COMPUTER SOFTWARE TOOLS Digitizing the Curve Using HQFIT Smooth and Reduce Transferring the Stage Discharge Table into the NewLeaf Database DAILY MEAN DISCHARGE SUBDIVIDED DAYS ALLOWABLE RANGE TABLES OTHER STAGE DISCHARGE RELATIONSHIPS LOOP CURVES TWO-GAUGE RELATIONSHIPS AREA VELOCITY CURVES REVERSE CURVES BANK OVERFLOW SUMMARY MANUALS AND REFERENCES OFFICE MANUALS REFERENCES iii

89 1.0 PURPOSE AND BACKGROUND A thorough understanding of the relationship between river stage and discharge is essential, since one of the basic responsibilities of a hydrometric technician is to collect and compute daily discharge data for publication purposes. A detailed knowledge of the steps involved in preparing the data for publication is required if hydrometric data are to be produced to national standards. Figure 1 illustrates the steps involved in manually computing streamflow data. The techniques presented in this lesson package are essential for other packages, such as open-water and winter computations. Figure 1: Flowchart for manual computation of streamflow data 1

90 2.0 OBJECTIVES The procedures for determining the stage discharge relation will be described. The effect of artificial and natural controls will be explained, and will include a discussion of loop curves (hysteresis), bank overflow, reverse curves, two-gauge relationships and area velocity curves. Procedures for plotting discharge measurement results will be described. This will be followed by an interpretation of the shape of the best-fit curve, which determines whether shift corrections are required. This will include procedures for low-water and high-water extension of curves from zero (if applicable) to the maximum gauge height. Procedures for the computation of stage discharge tables will be described, including curvilinear tables and allowable range tables (subdivision). Note that this lesson package explains the basics for determining the stage-discharge relation using manual computation procedures. These basic procedures must be understood. If it is also the intent to learn, at this time, how to perform these computations using the computer software tools, then include the sections which refer to these tools. 2

91 3.0 STAGE DISCHARGE CURVES 3.1 CURVE PLOTTING After all stage discharge information has been gathered, the technician determines the stage discharge relationship. First plot the measurements on a curve sheet, then determine the best fit curve. This procedure is explained in the following exercise which has been extracted from the Manual of Hydrometric Data Computation and Publication Procedures, pp Figure 2: Completed example of form M (R56) Figure 3: Blank arithmetic stage discharge curve sheet ( ) 3

92 a. Select scales on the curve sheet (form or ) so that the significant figures, as required for the stage discharge table, can be read with reasonable accuracy. Gauge heights are plotted on the vertical scale and the discharges on the horizontal scale. Suggested scales for the gauge height are 1 cm = 2, 1, 0.5, 0.2 or 0.1 m and for the discharge, 1 cm = 20,000, 10,000, 5,000, 2,000, 1,000, 500, 200, 100, 50, 10, 5, 2 or 1 m³/s. Make adequate provision for the entire range in stage which is known to have occurred during the history of the records. The stage discharge relationship may have to be shown in one or more curves to obtain the degree of accuracy required for the computation of the stage discharge table. Designate each curve as low water curve, high water curve, etc.; where feasible, carry each curve down to or near the zero flow stage. Allow for at least 0.3 m of overlap between curves and use more than one sheet, if necessary, to avoid cramping and confusion. b. When a new curve sheet becomes desirable, first plot all extreme high or low discharge measurements from former years on the new sheet. Then on this new sheet, plot the latest available stage discharge curve. Finally, plot all the open water measurements for the current year and, if necessary, plot a new stage discharge curve for the current year. c. Indicate the plotted point for each discharge measurement by a dot surrounded by an open circle about 2 mm in diameter. Circles that indicate measurements for previous years may be filled in with ink, which will distinguish them from the measurements made during the current year. Designate a discharge measurement by its date (e.g., June 12, 1967) with a diagonal line from the plotted point (use the same angle, say 60, on each sheet or draw the diagonal line about perpendicular to the curve). Measurements known to be affected by backwater may be plotted in pencil or by use of a distinctive symbol. To identify measurements made by another organization, use a different symbol (e.g., a triangle, square, or cross) with an explanatory note in the lower right-hand corner of the curve sheet. 3.2 DETERMINATION OF ZERO FLOW To complete the best-fit curve from the plotted measurements, determine the zero-flow stage for the station. Figure 4 graphically illustrates this method. A descriptive procedure follows the illustration. Figure 4: Graphical method for obtaining zero flow a. Plot the best-fit stage discharge curve from the discharge data available. b. Take three discharges that are in a geometric progression. (For example, 2, 4 and 8 m³/s). c. Plot up from 2 m³/s and across from 4 m³/s to obtain point (1). d. Plot up from 4 m³/s and across from 8 m³/s to obtain a second point (2). e. Draw a line through these two points. f. Draw a line through the points where 2 m³/s and 8 m³/s intersect the stage discharge curve (points (3) and (4)). g. The intersection of these two lines identifies the best estimate of the zero-flow gauge height. 4

93 3.3 CURVE EXTENSION For relatively new stations with few discharge measurements, it is often useful to extend the stage discharge curve beyond the highest discharge measurement available. The technician can accomplish this through the use of a logarithmic sheet (form ; Figure 5). Use the following procedure. Depending on the size of the stream, determine the gauge height corresponding to the point of zero flow to the nearest decimetre or to the nearest metre. Enter the gauge height in the space provided on form Plot the discharges against the difference between the mean gauge height for the discharge measurement and the gauge height at zero flow. In most cases, this logarithmic plot of measurements will form a straight line in the high water range. This makes it a useful tool in extending curves beyond the highest discharge measurement. The curve as determined in the log plot is then transferred to form or Figure 5: Blank logarithmic stage discharge curve sheet ( ) Figure 6: Completed logarithmic stage discharge curve sheet for example station 5

94 3.4 CURVE LABELLING The stage discharge curve must now be labelled. Use the following procedure : a. The first curve used in the first year of operation will usually be designated Curve No. 1. However, another number, such as 31, may be selected if desired, but do not start with No. 1 if this method of labelling curves was in use in previous years. b. Use a diagonal line from the curve to the notation. c. Label any succeeding curves as Curve No. 2, Curve No. 3, etc. (or Curve No. 32, Curve No. 33, etc.). d. Enter the dates for the period of use of each curve in the space provided. The information on the curve sheet should now be completed in ink. Figure 7: Completed stage discharge curve for example station 3.5 STAGE DISCHARGE CURVES USING COMPUTER SOFTWARE TOOLS Stage Discharge Curves may be drawn using NewLeaf software, and the stage discharge tables created. While the software is capable of automatically determining a stage discharge relationship, there is ample opportunity for human intervention, so the curve is in fact drawn by the technician. There are various software options that can be used to establish the stage discharge relationship. The options are referenced in the following sub-sections Filing Discharge Measurements The Stage Discharge Curve is developed by software called HQFIT, which is one of the Workbench options. This program uses discharge measurements which are stored in a file named c:\hqfit\sta-no.dat. There are two ways of entering the measurements into this field. 6

95 1. Measurement Input from NewLeaf 2. Measurement Input from Workbench Measurement input from NewLeaf is described in the following (which was previously covered under Lesson Package 10.3 Discharge Measurements by Wading ) : The measurements input into the NewLeaf database must be transferred into a file for use by Workbench. The selection of the measurements for this file to be used to establish the relationship is critical. 7

96 4.0 STAGE DISCHARGE TABLES We have now established our best-fit curve, complete with zero flow stage. The next step is to prepare a stage discharge table from the curve. Figure 8: Blank stage discharge table form M (R42) The following procedure is used to extract a stage discharge table from the stage discharge curve : a. Enter the number of the stage discharge table, which must correspond to the stage discharge curve number, in the space provided on form or Note that the initials of the computer and checker and the date the table was computed are also to be entered. b. When computing the stage discharge table, deviate as little as possible from the figures, as indicated by the curve. Express discharges to at least the same number of significant figures as required for daily discharges. c. In computing the stage discharge table, certain refinements may have been made in the computations to adjust for the fact that the curve may not have been a smooth curve. When the stage discharge table is completed, plot the values on the curve sheet to ensure that the original delineation of the curve is consistent with the table. d. In some cases, a new stage discharge curve is exactly the same as a former curve through part of the range in stage. In preparing the new stage discharge table for these areas, copy the data from the former table through the range of stage in which the new curve and the former curve are identical. Then compute the new table in the range of stage where the two curves diverge. The new table will cover the entire range of stage. e. If a stage discharge curve is extended above or below the original range, the same original number and date identification may be used. However, an explanatory note should be added on form , as well as the date when this extension was made. Note this applies only if the curve is extended and not if it is revised. f. Enter the dates in the space provided for the periods of use of each table. In some cases it may be desirable or necessary to show a discharge figure for every m of gauge height. For example, this table is convenient if flows during most of the year are confined to a relatively small range in stage or if a section of the curve is not totally smooth. Figure 10 illustrates the expanded stage discharge table form

97 Figure 9(a) Completed stage discharge table for example station Figure 9(b): Completed stage discharge table for example station Figure 10: Blank expanded stage discharge table form M (R42a) 9

98 4.1 STAGE DISCHARGE TABLE USING COMPUTER SOFTWARE TOOLS There are also various ways that the stage discharge table can be computed from the stage discharge curve, as discussed in the following sub-sections : Digitizing the Curve If the curve has been drawn manually (as previously described in sections 3.1 to 3.4) it may be digitized to convert it into a table Using HQFIT The stage discharge table can be produced as output from drawing the curve using HQFIT, as was described in section Smooth and Reduce The next step is to refine the table (from or 4.1.2) by producing a smoother relationship with fewer points to define the relationship. This refining is produced by Workbench programs Transferring the Stage Discharge Table into the NewLeaf Database The table which has been produced needs to be transferred into the NewLeaf database so that it will be available for discharge computations. 10

99 5.0 DAILY MEAN DISCHARGE 5.1 SUBDIVIDED DAYS Normally the daily mean gauge height is used to compute the daily mean discharge. However, a daily mean discharge determined directly from the daily mean gauge height may be in error for a number of reasons. These reasons include : a. the rate of change in stage; b. the relative condition of the river (high or low); c. the shape of the stage hydrograph for the day and the proportion of time during which the stage is relatively high or low; d. the relative curvature in the stage discharge curve in the range of stage recorded during the day. To obtain a more accurate determination of the daily discharge, it may be necessary to subdivide the day into two or more parts, determine the mean gauge height for each part, and determine the discharge for each mean gauge height. From these, compute the weighted mean discharge for the day (use form R241, R241A or a blank sheet). If the resultant weighted mean discharge differs from that determined using the mean gauge height by more than a selected allowable limit, say 2% for discharge above 0.3 m³/s, then subdivision is necessary for all similar conditions. To determine whether you need to subdivide, examine the chart and select a few sample days that may be critical because of the conditions listed in (a) to (d). Compute the daily mean discharge for these days : (1) from the daily mean gauge height, and (2) by subdivision. A few tests of this nature will provide the technician with the necessary experience for the particular station upon which to base his decision regarding the necessity of subdivision. Figure 11: Example illustrating manual subdivision of days 11

100 5.2 ALLOWABLE RANGE TABLES Allowable range tables may be used to determine if a day for a particular station needs to be subdivided. The following trial and error procedure is used for drawing up allowable range tables. A hypothetical example extracted from the Manual of Hydrometric Data Computation and Publication Procedures, page 27, is used to illustrate the procedure : a. From the stage discharge table, select a range in stage during medium flow, for example, from 3.0 to 4.0 m. Suppose that the discharge at gauge height 3.0 m equals 186 m³/s and the discharge at gauge height 4.0 m equals 339 m³/s. The mean discharge for this range in stage would then equal 262 m³/s. However, you observe that at a mean gauge height of 3.5 m, the discharge is only 252 m³/s. This represents a difference of 4% (10 divided by 262 x 100) which is not allowable. b. Select a smaller range, for example from 3.0 to 3.4 m. Calculate the mean discharge for this range in stage. Compare the mean discharge with the actual discharge at the mean gauge height for this range. Now you get a difference of 1%. This is too low, but 3.0 to 3.6 gives 2%. c. Now try between 4.0 and 4.6. This gives a 1% difference, which is too low. Try between 4.0 and 5.0, which gives a 3% difference. Therefore, an allowable range of 0.8 m is about right. d. The range from 6.5 to 7.5 will give 2%. e. After several such attempts, you will develop an approximate allowable range table. f. When in doubt, subdivide. 12

101 6.0 OTHER STAGE DISCHARGE RELATIONSHIPS 6.1 LOOP CURVES Sometimes the discharge for a given stage at a particular station is larger when the stream is rising than when it is falling. This produces a loop (or hysteresis) curve. On a simple stage discharge curve, it will be found that measurements made on a rising stage tend to plot to the right of the curve, while those made on a falling stage tend to plot to the left. As stated in Rantz et al., 1982, page 414 : The discharge measurements for individual flood waves will commonly describe individual loops in the rating. In other words, there will be a different loop for each flood. The departure of measurements from the rating curve for steady flow is of significant magnitude only if the slope of the stream is relatively flat and the rate of change of discharge is rapid. For gauging stations where this scatter of discharge measurements does occur, the discharge rating must be developed by the application of adjustment factors that relate steady flow to unsteady flow. (Unsteady flow refers to discharge at a site that changes appreciably with time, as in the passage of a flood wave). 6.2 TWO-GAUGE RELATIONSHIPS Discharge through a river reach can be computed by the Manning equation if a stage recorder is located at both the upstream and downstream ends of the reach. As described in Rantz et al. (1982), pages 423 to 425, discharge measurements would be made for the purpose of determining the Manning roughness coefficient (n) from the measured discharge, thereby obtaining the only unknown factor needed to compute the conveyance (K) at each end of the slope reach. The value of n, computed from a discharge measurement, usually would not represent the true value of the roughness coefficient, but would actually be a catch-all value that included the effect of error in the computed value of the energy slope in the reach. The computed values of n would likely vary with stage. Figure 12: Example of a stage discharge loop (after Rantz etal., 1982, p. 413) 13

102 The discharge computations would proceed along the following lines : The basic form of the Manning equation is : Q = KS 1/2 where Q = discharge K = conveyance, which is equal to : AR 2/3 n (A is area and R is hydraulic radius) S = energy gradient. The foregoing equation is in metric and can be expanded to : Missing Equation where F L g μ = fall in the reach = length of reach = the acceleration of gravity = the velocity-head coefficient whose value is dependent on the velocity distribution in the cross-section k = the coefficient of energy loss whose value is considered to be zero for contracting reaches and 0.5 for expanding reaches. Subscript 1 refers to the upstream cross-section. Subscript 2 refers to the downstream cross-section. For the cross-section at each end of the slope reach, relations would be prepared between stage and each of the following three elements : K, A, and μ. A computer program would be written to solve the above equation. Then, given the stage at each end of the reach, the computer would compute F, A, K, μ, and finally Q. In order to apply the above procedure correctly, the water surface fall through the reach must be determined. The measured fall is an index of the water surface slope but caution must be exercised in locating gauges if slope ratings are to be used : The location of gauges is a factor in determining the reliability of slope ratings and where there is a choice, several items should be considered. Both the base gauge and the auxiliary gauge should be stilling wells, or both should be bubble gauges that compensate identically for temperature. The gauges preferably should be far enough apart that minimum fall will exceed 0.5 ft. and there should be no significant tributaries or other sources of variable backwater between them. The base gauge is best located at the discharge measuring section to eliminate storage adjustments. Where backwater is intermittent, the auxiliary gauge should be downstream. This arrangement gives the most sensitive relation between fall and discharge and provides for positive identification of non-backwater periods. Where backwater is always present, or is caused by the return of overbank flow that has about the same magnitude upstream as it does downstream, an upstream auxiliary gauge is about as good as one downstream. Careful attention to the details of field operation (such as precise synchronization of base and auxiliary recorders, close datum control, and avoidance of current meter measurements at velocities seriously below 14

103 the limits of accurate meter registration) will improve the reliability of the lower parts of slope ratings. Techniques that do not involve current meters can be used for low-water extensions of slope ratings at some sites. A power dam close to the gauge may be a source of discharge information. Power production records usually include discharge figures, and, if all flow is through the turbines, as it generally is during low-flow periods, the discharge records during steady-flow periods may be used instead of discharge measurements. A dam downstream, where flow is cut off for long periods, may provide a reservoir that can be used as a container for volumetric measurements. Using records for other stations as a basis for extending a slope rating downward is usually a dubious practice. However, even that procedure may be more accurate than using current meter measurements, whose mean velocities are less than 0.10 ft/s. [Kennedy, 1984, p. 38] 6.3 AREA VELOCITY CURVES To define an area curve in extensions of areas and velocities, plot the area of crosssection against gauge height. This area curve may be accurately defined by surveys to the highest desired stage. The average velocity in the section, as determined for each discharge measurement, is similarly plotted against gauge height. For channels not subject to overflow, the velocity curve generally approaches a straight line at high stages, and reasonably good extensions may be made by the use of judgement and experience. The Figure 13: Stage area and stage velocity curves discharge for the flood stage is computed as the product of the area and velocity from the extension of the two curves. In the application of this method, consideration should be given to the existence of a definite relation between the stages at the measuring station. Note These curves can also be used to determine an error in a discharge measurement (i.e., if a measurement plots to the left of the stage velocity curve, the velocity meter may have been damaged, causing an error in the measurement. If a measurement plots off the stage area curve, chances are that there was an error in depth soundings or width calculations during the measurement). 15

104 6.4 REVERSE CURVES A reverse curve (or S-curve) is produced when there is a change in control at a certain stage of the stream, (i.e., from riffle control to channel control). The change could be caused by bank erosion (undercutting), severe weed or willow growth at a certain height on the stream banks causing backwater, or in the case of the example, a roadbed taking over as the control after the culverts become submerged. It is essential that discharge measurements be made to define the curve where the break in the curve occurs. Figure 14: Example of a reverse curve with two controls 6.5 BANK OVERFLOW When a stream overflows its bank, the stage discharge curve usually shows a noticeable break to the right. This is caused by a large increase in the area over a relatively small increase in stage. This in turn results in a large increase in discharge. It is very important to define the stage where this occurs. This can be done by recording the stage, using levels or other means, but best results are obtained if discharge measurements are available to define the stage discharge curve. 16

105 7.0 SUMMARY Determination of the relationship between river stage and discharge at a hydrometric station is essential to the collection and computation of high quality hydrometric data. The field technician must have a thorough knowledge of the effects of natural and artificial controls on the stage discharge relationship, including loop curves and reverse curves. This lesson has addressed these concepts and has described, through various examples, the procedures required for plotting the stage discharge curve. This has included curve documentation, low-water and high-water curve extension, and the computation of stage discharge tables. Considerable practice of these techniques will be required in order for the technician to become totally conversant with these skills. 17

106 8.0 MANUALS AND REFERENCES 8.1 OFFICE MANUALS Environment Canada, Inland Waters Directorate, Water Resources Branch, Manual of Hydrometric Data Computation and Publication Procedures, Fifth Edition, 1980, Ottawa, 51 pp. 8.2 REFERENCES Kennedy, E.J., (1984), Discharge Ratings of Gaging Stations, in Techniques of Water-Resource Investigations of the U.S. Geological Survey, Book 3, Chapter A10, Washington, 59 pp. Rantz, S.E. et al., (1982), Measurement and Computation of Streamflow: Volume 2. Computation of Discharge, U.S. Geological Survey, Water-Supply Paper 2175, Washington. 18

107 THE WATER SURVEY OF CANADA HYDROMETRIC TECHNICIAN CAREER DEVELOPMENT PROGRAM Lesson Package No. 19 Computation of Daily Discharge (Open Water) V.S. Elder Water Survey of Canada Environment Canada P.O. Box th Avenue Peace River, Alberta Canada T8S 1S1

108 Copyright All rights reserved. Aussi disponible en français

109 TABLE OF CONTENTS 1.0 PURPOSE AND BACKGROUND OBJECTIVES INTRODUCTION COMPLETION OF DISCHARGE MEASUREMENTS FORM DISCHARGE MEASUREMENTS FORM ( ) DISCHARGE MEASUREMENTS IN NEWLEAF DATABASE SHIFT AND BACKWATER CORRECTIONS INTRODUCTION COMPUTATION OF SHIFT AND BACKWATER CORRECTIONS DISTRIBUTION OF SHIFT AND BACKWATER CORRECTIONS Linear Distribution over Time Stage-shifting Application of Corrections Example Problem COMPUTATION OF DAILY DISCHARGE USING NEWLEAF Measurement Shifts Shifts and Backwater Corrections Computing the Values Additional Workbench Computation Aids Digitizing Hydrograph Stream Accounting Program (SAP) SAVE File Extractor Plotting Hydrographs Printing Annual Pages SYMBOLS AND FOOTNOTES SYMBOLS WHEN USING MANUAL COMPUTATION PROCEDURES STATION ANALYSIS SUMMARY MANUALS AND REFERENCES OFFICE MANUALS REFERENCES CAREER DEVELOPMENT PROGRAM iii

110 1.0 PURPOSE AND BACKGROUND One of the basic objectives of a hydrometric technician's work is to gather data for the eventual publication of daily discharges. A detailed knowledge of the steps involved in preparing data for publication is, therefore, essential. The computation of open water daily discharges is a necessary and central task in the procedure and must be thoroughly understood if quality data are to be produced. It should be stressed that the computation methods discussed in this module are mainly manual computations procedures performed without the aid of electronic data processing equipment. To truly understand the basic concepts of discharge computations, the data must be manipulated manually. Procedural mistakes could well arise later if the technician is not aware of the functions the computer is performing during automatic computations. 1

111 2.0 OBJECTIVES The objectives of this lesson package are to : compute daily discharges under open-water conditions, given an established stage discharge relationship and a gauge height record; define shift corrections; list situations in which shift corrections are required; use meteorological information to verify daily discharge computations. 2

112 3.0 INTRODUCTION Daily discharges are computed from a record of gauge heights and actual discharge measurements obtained for the hydrometric station during the year. If a stable stage discharge relation has been determined for the station, then relatively few discharge measurements may be required during the year to confirm the stage discharge curve. The computation of daily discharges is relatively straightforward in this case. On the other hand, if the stage discharge relation is poorly defined, more measurements of discharge will be required to compute the record. Figures 1a and 1b illustrates the steps involved from data collection through to data publication. It can be seen that gauge heights must be computed for each discharge station before daily discharges can be computed. The procedures involved in computing gauge heights have been detailed in Lesson Package No. 8. For the purpose of this lesson package it is assumed that gauge height computations are well-understood. This includes an understanding of the purpose and application of the gauge history form ( ) and the determination and distribution of gauge corrections to both manual gauges and recording gauges. It is also assumed that the concepts of the stage discharge relation, as discussed in Lesson Package No. 18, are understood. In summary, this lesson package describes the computation of daily discharge under open-water conditions, given an established stage discharge relation and a gauge height record (or corrected water levels if using NewLeaf Computations). Figure 1a: Flowchart for manual computation of streamflow data Figure 1b: Flowchart for automated computation of streamflow data 3

113 4.0 COMPLETION OF DISCHARGE MEASUREMENTS FORM 4.1 DISCHARGE MEASUREMENTS FORM ( ) Notes and records obtained in the field form the basis of the office computation of hydrometric survey data. It is essential that all data be identified at every step in the computation process. Once the daily gauge heights have been determined, the Discharge Measurements Form M must be completed for all discharge measurements obtained during the year. An example for a fictitious station is shown in Figure 2. These steps are outlined in this section. a. Enter the date of the discharge measurement. If a non-conventional technique, such as moving boat, fluorometric, etc., was used in measuring the discharge, indicate the method of measurement in the Remarks column. b. Enter the name of the person who made the measurement. If the measurement was made by the USGS, PFRA, or any other cooperating organization, only the name of the organization need be indicated. c. Enter the air and water temperatures as obtained at the time of the measurement. d. Enter the width, area, mean velocity and discharge, using significant figures as shown. If ice is present in the stream, or if the discharge is estimated, insert the appropriate reference or symbol in the Remarks column. e. Extract the weighted mean gauge observation corresponding to the measured discharge from the front sheet of the discharge measurement notes (Form ). Apply the appropriate gauge correction from Form to this observation and enter the result in the Mean Gauge Height column. If the gauge height corresponding to no flow is determined, enter it in the Remarks column. If there are unusual conditions affecting the stage discharge relation, such as inflow between the gauge and the measuring section, note this in the Remarks column. f. If discharge measurements at a station are made at more than one location, a symbol should be entered under Remarks to distinguish them in the event that is is necessary to use the cross-sectional area or the mean velocity. g. If any other information pertinent to the discharge measurement is obtained, note this in the Remarks column. 4.2 DISCHARGE MEASUREMENTS IN NEWLEAF DATABASE The discharge measurement information can be entered into the NewLeaf database, instead of on the paper forms. This information can then be viewed on the monitor displayed similar to the discharge measurement form Figure 2: Discharge Measurements form M, Sample Creek near Sampleburg 4

114 5.0 SHIFT AND BACKWATER CORRECTIONS 5.1 INTRODUCTION The Discharge Measurement Form M must now be completed by determining the shift or backwater correction associated with each discharge measurement entered on the form. A shift is defined as a temporary change in the stream control which alters the stage discharge relation. The stage discharge relation is not permanent at most stations but varies gradually or abruptly because of changes in the physical features of the control. If the change in the rating persists for several months, this may be an indication that a new rating curve should be prepared for the period of time during which the new stage discharge relation is in effect. If the change is of short duration, the original rating curve is still effective but, during this period, shifts or adjustments must be applied to the recorded stage to determine the corresponding discharge. Frequent discharge measurements must be made during this period to define the magnitude of the shift(s). Backwater is defined as a temporary rise in stage produced by an obstruction in the stream channel caused by ice, weeds, control structure, etc. The difference between the observed stage for a certain discharge and the stage as indicated by the stage discharge relation for the same discharge is reported as the backwater at the station. 5.2 COMPUTATION OF SHIFT AND BACKWATER CORRECTIONS The computation of shift and backwater corrections is as follows ( Manual of Hydrometric Data Computation and Publication Procedures, p. 30) : 1. For many stations, a shift in the station control or a backwater condition may occur at certain times during the year as a result of weed effect, beaver action or ice conditions. During such periods, shift or backwater corrections are determined from available discharge measurements. These corrections are entered on Form and used subsequently to compute daily corrections, which are applied in the determination of the daily discharges. 2. However, apart from these measurements which plot off the curve for reasons indicated above, most of the measurements will plot somewhat off the curve as a result of normal scatter. For these, no correction is computed; however, it is normally found useful for purposes of expressing mathematically the degree of scatter to indicate for each measurement the percentage difference between measured discharge and the discharge indicated by the stage discharge relation. These percentage differences are entered in the Diff. column on Form M. If desired, these differences may be expressed in cubic metres per second instead of percentage for discharges less than about 0.5 m³/s. 3. Following is an example of the computation of shift and backwater corrections, and the difference between measured discharge and the indicated discharge from the stage discharge table : a. From a discharge measurement (Form M), the mean gauge height is m and the discharge is 3150 m³/s. From the stage discharge table, the discharge of 3150 m³/s corresponds to a gauge height of m, indicating that a shift correction of m would have to be applied to the mean gauge height for the day to produce results consistent with the discharge measurement. b. From a discharge measurement (Form M), the mean gauge height is m and the discharge is 708 m³/s. From the stage discharge table, the gauge height of m corresponds to a discharge of 696 m³/s. 5

115 The difference between the measured discharge and that indicated by the stage discharge table is : ( ) = 1,7 % (696 x 100) 4. A discharge measurement made during the computation period may plot substantially off the stage discharge curve. If, after careful analysis and review, no satisfactory cause of its departure from the stage discharge curve can be determined, the measurement should be eliminated from use in the computation. In this instance, do not enter any figure in the Shift or Diff. columns, but enter an explanatory note in the Remarks column on Form M, as well as on Station Analysis Form Figure 3 illustrates an example of a Discharge Measurements Form M for a fictitious station, 01AA001 Sample Creek near Sampleburg. This table has been completed by computing and entering the shift or backwater corrections based on the stage discharge table (Figure 4) and the stage discharge curve (Figure 5). The first nine ice condition shifts have also been computed, although they will not be distributed. Figure 3: Completed Discharge Measurements Form, Sample Creek near Sampleburg 6

116 Figure 4(a): Stage discharge Table (page 1 of 2), Sample Creek near Sampleburg Figure 4(b): Stage discharge Table (page 2 of 2), Sample Creek near Sampleburg Figure 5: Stage discharge curve, Sample Creek near Sampleburg 7

117 5.3 DISTRIBUTION OF SHIFT AND BACKWATER CORRECTIONS Several methods of distributing shifts may be used. Two of the more common methods are stage-shifting and linear distribution by time. These techniques will be briefly discussed here. A more comprehensive treatment of shifts may be found in Rantz et al. (1982), pages Linear Distribution over Time If the date on which the change occurred is not known, assume that the change occurred uniformly and distribute the correction in accordance with one of the two following methods : a. Divide the change in the correction by the number of days to find the change per day. For example : Suppose the correction was found to be on March 20 and on March 30. The number of days involved is 10 and the change in correction is The change per day is The corrections to be applied are shown to the nearest thousandth of a metre. b. When the change is small and the number of days is large, the preferable method is to divide the number of days by the change in correction. For example : Suppose the correction is on May 25 and on October 15. Dividing the period of 144 days by 3 gives 3 intervals of 48 days each. No change in correction will be applied during the first one-half interval of 24 days, i.e., the correction will be continued from May 25 to June 17; an increase of in the correction will be applied during each of the next two intervals of 48 days, i.e., a correction of from June 18 to August 4 and from August 5 to September 21. The remaining change will be applied during the remaining one-half interval, i.e., the final correction of will be applied from September 22 to October Stage-shifting Stage-shifting is normally done because of a temporary, or short-term condition at a gauging station. For example, perhaps a minor peak has occurred at a station, and discharge measurements indicate a significant change to the stage discharge curve at the higher stage. A short time later, a major flood drastically alters the stage discharge relationship, requiring an entirely new stage discharge curve. Instead of drawing two new curves with accompanying rating tables, the minor peak may be stage-shifted, and a new curve can be drawn for conditions following the major flood Application of Corrections The manual computation of stream discharges under open water conditions requires the application of shift and backwater corrections for most stations. In practice, the Backwater Computations Form M (R205) is often used as a rough work sheet (Figure 6). These corrections are then transferred to Daily Discharges Form M (R79) which, in effect, becomes a final document (Figure 7). The following procedure should be used : 1. In the space provided on Form M, enter the number and date of each stage discharge table that is to be used, and indicate the specific period for which each table applies. 2. If no shift or backwater corrections are applicable, use the stage discharge table and the gauge heights directly to obtain the daily discharges. 3. If shift or backwater corrections are to be applied, rule in an extra column to the right of the gauge height column. Enter for the appropriate dates the correction established by the respective discharge 8

118 measurements. Circle these corrections. The distribution of the shift or backwater corrections from day to day will depend upon the interpretation of the cause of the shift; enter a brief explanation of the interpretation used on the Station Analysis Form Distribution may be made on a straight-line basis in accordance with one of the methods described in section 5.2. Instead of using an extra column on Form M for entering shift or backwater corrections, it may be more desirable in some cases to apply these corrections by the use of Form M. 4. Enter on Form M the daily discharge as computed on the subdivided-day work sheet Example Problem The distribution of shifts can be demonstrated through the computation of open-water discharges for the example station Sample Creek near Sampleburg. The discharges should be computed for this station after each shift condition is determined. Figure 7: Daily Discharges Form M (R79) Figure 6: Backwater Computations Form M (R205) The first six shifts from April 16 to May 2 are straightforward and should be straight-lined and entered on Form M. The June 5 measured shift of will be stage-shifted. The May 2 shift (0.000) was used through to June 3; thus, no shifts are necessary up to and including the subdivided days of May 9 to 13. The discharges from April 16 up to the subdivided days can now be computed. In the example station, Sample Creek, subdivided days ( V shown in the gauge height column of Figure 8) are shown for May 9 to 13. The gauge heights and times are shown on the 13 Columns Form (R241) (Figures 9 and 10). The gauge heights have been corrected for the datum correction. A reversal correction is shown and must be subtracted from the listed gauge heights. 9

119 Figure 8: Daily Gauge Heights, Sample Creek near Sampleburg Figure 9: 13 Columns Form, Sample Creek near Sampleburg, May 9 11 Figure 10: 13 Columns Form, Sample Creek near Sampleburg, May

120 Two methods of subdivision are shown : 1. May 9, 12 and 13 are subdivided by the more common increment-mean method, where the mean has been calculated for each segment by balancing areas graphically. 2. The second method, used for May 10 and 11, is the point-intercept method (sometimes called flood subdivision). The advantage of using the point-intercept method is that the daily mean discharge computation would agree with that produced should a flood report be required, as the discharge hydrograph would be reproduced using the point-intercept method. The point-intercept method is also easier to work with when large changes in stage and several reversals are encountered. When using either method, the stage increments should be less than the ranges shown on the allowable range table. It should also be noted When using the increment-mean method, that the computations are simplified if the numerical values of the hours can be reduced by factoring, as in the May 9 example. The subdivided days, May 9 to 13, should now be computed. Assume that the June 5 measurement at Sample Creek has been verified and reflects a condition in effect at the time of the peak. A temporary curve can be pencilled in, hitting the June 5 measurement, and rejoining Curve 1 near a stage of 1.2 m. In effect, a new, temporary rating curve will be used to reflect conditions at the station at that particular time, and may not be used thereafter. When the final computations are completed, the stage-shift curve may be erased. From the curve, it can be seen that the gauge heights up to June 3 are below the point where the stage-shift curve diverges from Curve No. 1, and are used with zero shifts. The discharge for June 4, gauge height m, can be read directly from the stage-shift curve. The shift can also be measured between the two curves and the rating table value is then used. The discharges for June 5 to 8 are obtained in the same manner. Conditions were assumed to be unchanged from June 9 to the measurement of June 28. The measured shift of June 28 was used for the period (+.002 m). Shifts caused by scour and fill are not dealt with in the Sample Creek example. However, shifts caused by scour (usually on the rising limb of a peak positive shifts) and fill, or silting (usually on the recession limb of a peak negative shifts) may be dealt with in a manner similar to the stage-shift example, using temporary stage-shift curves. The most valuable tool in analyzing the stream's behaviour is the discharge measurement; but a knowledge of the stream's behaviour in the past and the technician's experience are also valuable. The shifts should now be distributed and the discharges computed for the May 14 to June 28 period. Shifts may also be interpolated other than by straight-lining because of other conditions affecting the stage discharge relationship. For instance, beaver dams below the station may flood the control and cause dramatic increases in stage. Discharge measurements and observations are extremely valuable, but as well, the rises in stage caused by the gradual addition to the beaver dam (usually during the late afternoon to early morning hours) may sometimes be interpolated from the chart record at automated stations. In the Sample Creek example, the September 19 measurement was noted to have been made when leaves and debris had lodged on the control, causing a negative shift. In this case, meteorological records indicate there was no significant rainfall in the area, and the hydrographs of nearby stations showed the flows to be relatively uniform throughout the period. 11

121 The shift of made on August 21 was carried to September 6, when the effects of the debris lodging on the control became apparent, then straight-line interpolated from September 7 to the measured value of on September 19. Since the gauge heights continued to increase past September 19, and again no increase in flow is justified, the shifts were also increased at a uniform rate, to m on September 22. The leaves and debris apparently were washed away gradually, and a stable condition was reached on October 2. The shifts were then straight-line interpolated from on September 22 to on October 2, through to the measured value of on October 31. The shifts should now be distributed for the June 28 to October 31 period. The discharges should now be distributed for the June 28 to October 31 period. Figure 11 shows the completed Daily Discharges Form M for Sample Creek near Sampleburg. Figure 11: Completed Daily Discharges Form, Sample Creek near Sampleburg 12

122 5.4 COMPUTATION OF DAILY DISCHARGE USING NEWLEAF The daily discharges, as well as the daily maximum/minimum and the annual instantaneous maximum/minimum discharges, can be computed using the NewLeaf Computations software. One of the benefits of using the computer for discharge computations is that the discharges are computed for each water level value, instead of for the daily mean only. This eliminates the need for computing using sub-divided days, since the computer sub-divides automatically Measurement Shifts The amount that the measurements are off the Stage-Discharge Curve are calculated by the computer Shifts and Backwater Corrections The shifts and backwater which are to be applied in calculating the discharge are entered into a shift corrections table (either Time Based Shifts or Stage Based Shifts). This procedure is described in detail in the following : Backwater corrections due to ice is the subject of a separate Lesson Package No. 20, Computation of Daily Discharge (Ice Conditions) Computing the Values The daily discharges can be computed using the NewLeaf Computations software Additional Workbench Computation Aids There are several other software programs which may be used for hydrometric computations, which are part of the Workbench system. They are referenced in the following sub-sections Digitizing Hydrograph Data for missing periods, or periods under backwater, are frequently estimated by manually drawing a trace on the standard hydrograph paper. This trace can be digitized and stored in the NewLeaf database in the override table Stream Accounting Program (SAP) This program is used for comparing stations, when there are a number of stations in a river basin. Upstream stations on tributaries can be summed (or subtracted) and compared to downstream stations SAVE File Extractor This program is used to extract historical data from SAVE files Plotting Hydrographs Hydrographs, including measurements, can be plotted on paper using programs which were originally developed as part of routines. The daily discharge values and measurements must first be exported from the NewLeaf database to the proper directory in the correct format Printing Annual Pages 13

123 Printing the annual pages was previously referenced in section There are two alternatives for producing a printed output, one via NewLeaf Computations and the other via Workbench options. For detailed instructions, see the following : Hydrographs, including measurements, can be plotted on paper using programs which were originally developed as part of routines. The daily discharge values and measurements must first be exported from the NewLeaf database to the proper directory in the correct format. 14

124 6.0 SYMBOLS AND FOOTNOTES 6.1 SYMBOLS WHEN USING MANUAL COMPUTATION PROCEDURES For the period of record shown on the Sample Creek example, only one symbol was used the manual gauge, or partial day A symbol on October 31, when the station was shut down for the winter. It should be noted when computing stations manually, using the (R79) form, that the symbol is shown to the right of the daily discharge. If only stage were recorded at a station, the symbol would be shown to the right of the daily stage figure. The following has been obtained from the Manual of Hydrometric Data Computations and Publication Procedures, pages 12 and 13. a. A Manual Gauge Use this symbol during open-water periods to identify the use of one or more manual gauge observations to obtain a daily stage at a station where the water-stage recorder was temporarily out of operation. Enter this symbol to the right of the daily discharge figure or to the right of the daily stage figure if no discharge data are shown. This symbol will also be used when the chart record is available for only part of a day. During a year when a recorder is installed, the symbol A will be used on all days prior to the chart records to identify manual gauge readings. Do not enter this symbol in any monthly or annual summary data, except for the extremes in the annual summary, if applicable. Do not use this symbol during ice periods. However, a footnote will be required if the recording gauge was not in operation in winter periods. Use of this symbol must be accompanied by an appropriate reference in a footnote (i.e., A Manual gauge). The symbols B or E have precedence over the symbol A. b. B Ice Conditions Use this symbol to indicate that ice conditions in the stream have altered the open water stage discharge relationship. The symbol is entered to the right of the daily discharge figure. This symbol will not be used for water level data. However, if it is required for specific stations, an appropriate explanation should be given in the Station Analysis Form Do not enter this symbol in any monthly or annual summary data except for the extremes in the annual summary, if applicable. Use of this symbol must be accompanied by an appropriate reference in a footnote (i.e., B Ice conditions). The symbol B has precedence over the symbols A and E. c. D Dry Use this symbol to indicate that the stream or lake is dry or that there is no water at the gauge. This symbol is used as an updating correction in the MANUAL program or as input to the LEVELS file, and the word DRY will appear without a footnote in the gauge height column. d. E Estimated Use this symbol whenever the discharge during open-water periods was determined by some indirect method, such as interpolation, significant high-water extension, comparison with other streams, or by correlation with meteorological data. If desired, the method of estimate may be given in a suitable footnote. Enter this symbol to the right of the daily discharge or daily water level figure. Do not use this symbol during ice periods. Do not enter this symbol in any monthly or annual summary data except for the extremes in the annual summary, if applicable. Use of this symbol must be accompanied by an appropriate reference in a footnote (i.e., E Estimated). The symbol E has precedence over the symbol 15

125 A. e. Where one of the symbols A, B or E is applicable, show either a symbol for each day or only a reference in a footnote. Show a symbol for each day if the symbol applies to more than two periods; otherwise, show only a reference in a footnote. However, the output listing from the FLOW or LEVELS files or the digitizer applications and related programs will show a symbol for each day, where applicable, regardless of the duration. Examples of footnotes without symbols are as follows : Manual gauge, May 20 to July 20 and August 21 to 23. Ice conditions, January 1 to April 10 and October 27 to December 31. Estimated, June 1 to 29. f. V Subdivided Use this symbol when the daily gauge height record is subdivided into two or more periods to compute the daily discharge. Enter this symbol in the gauge height column and omit the daily mean gauge height for that day. However, if a daily water level is required to compute monthly mean water levels, it is to be computed from the continuous water level record and not from the daily discharge (the symbol V in this case would be shown to the right of the daily water level). Use of this symbol must be accompanied by an appropriate reference in a footnote (i.e., V Subdivided). However, note that this symbol will not appear in any publications. g. Enter the following footnote on the Station Analysis form , with the appropriate dates, when any part of a streamflow or water level record has been prepared by computer methods : Data to processed by digitizer and computer methods. h. In summary, although only the symbols A, B, D, E or V will be used, only the symbols A, B or E will be accompanied by a footnote in the data publications or on printouts. Explanatory footnotes may be used if the symbol applies to one or two periods, or to explain that the recording gauge was not in operation during all or part of winter periods or that a gauge height graph was used for a certain period. Examples of footnotes are as follows : Recording gauge not in operation during ice periods. Recording gauge not in operation, January 1 to March 5 and November 15 to December 31. Recording gauge not in operation continuously during the ice periods. Gauge heights from graph of observed readings, May 20 to June 10. i. The computer output for daily discharges and water levels will show a symbol for each day, where applicable. 16

126 7.0 STATION ANALYSIS Although the station analysis form will not be dealt with in this lesson package, the participants should be aware that pertinent facts regarding the open water computations should be noted for eventual inclusion in the station analysis. Relevant points should be mentioned throughout the course : for instance, the reasons for the distribution of the gauge and shift corrections, including the stage-shifting; the period of use of stage discharge tables; etc. In particular, any deviation from the commonly practised computation procedure should be tabulated for the station analysis. The completion of the Station Analysis form will be covered in detail in Lesson Package No. 22 Station Analysis Form. 17

127 8.0 SUMMARY The manual computation of stream discharge data has been described in this lesson package and the procedures reinforced through an example problem. The participants should now be able to compute shifts and distribute these shifts by straight-line interpolation or stage-shifting. Daily discharges can now be computed by addition or subtraction of shifts from the daily gauge heights in conjunction with the stage discharge table. The participants should also be familiar with various symbols and footnotes required to document the computation process. Possibly the option of computing the discharge data using computer software tools was also introduced during this lesson package. The technician should then be capable of performing the computations using either the manual method or the NewLeaf Computations software method. 18

128 9.0 MANUALS AND REFERENCES 9.1 OFFICE MANUALS Environment Canada (1980), Manual of Hydrometric Data Computation and Publication Procedures, Inland Waters Directorate, Water Resources Branch, Ottawa, 51 pp. 9.2 REFERENCES Rantz, S.E. et al., (1982), Measurement and Computation of Streamflow: Volume 2, Computation of Discharge, U.S. Geological Survey, Water Supply Paper 2175, Washington, D.C. 9.3 CAREER DEVELOPMENT PROGRAM Lesson Package 8 Gauge Height Computations Lesson Package 18 Stage Discharge Relation Lesson Package 20 Computation of Daily Discharge (Ice Conditions) Lesson Package 22 Station Analysis Form 19

129 THE WATER SURVEY OF CANADA HYDROMETRIC TECHNICIAN CAREER DEVELOPMENT PROGRAM Lesson Package No. 20 Computation of Daily Discharge (Ice Conditions) B. Poyser and R. Leblanc Water Survey of Canada Environment Canada 75 Farquhar Street Guelph, Ontario Canada N1H 3N4 D. Kirk Water Survey of Canada Environment Canada Ottawa, Ontario Canada K1A 0H3

130 Copyright All rights reserved. Aussi disponible en français

131 TABLE OF CONTENTS 1.0 PURPOSE AND BACKGROUND OBJECTIVES INTRODUCTION GENERAL CONSIDERATIONS EFFECT OF ICE ON THE STAGE DISCHARGE RELATION Introduction Frazil Ice Anchor Ice Surface Ice Computation of Discharge during Periods of Anchor Ice Computation of Discharge during Periods of Surface Ice Computing Daily Mean Discharges on Days Discharge Measurements Were Taken Example Exercises METHODS OF COMPUTATION Introduction Methodology Preparation BACKWATER METHOD Introduction Graph Preparation ADJUSTED DISCHARGE METHOD INTERPOLATED DISCHARGE METHOD RECESSION CURVE METHOD EFFECTIVE GAUGE HEIGHT METHOD MODIFIED BACKWATER METHOD K FACTOR METHOD DOCUMENTATION QUALITY CHECKING OF COMPUTATIONS SUMMARY MANUALS AND BIBLIOGRAPHY MANUALS BIBLIOGRAPHY APPENDIX A: EXERCISES BASED ON EXAMPLES...31 Exercise 1: Oxtongue River near Dwight Exercise 2: Humber River at Weston Exercise 3: Lynde Creek near Whitby APPENDIX B: COMPUTATION EXERCISES...37 Example 1: Backwater Method, Nith River near Canning ( ) iii

132 Example 2: Backwater Method, Peace River at Peace Point ( ) Example 3: Adjusted Discharge Method, Nith River near Canning ( ) Example 4: Adjusted Discharge Method, Peace River at Peace Point ( ) Example 5: Interpolated Discharge Method, Nith River near Canning ( ) Example 6: Interpolated Discharge Method, Peace River at Peace Point ( ) Example 7: Recession Curve Method, Peace River at Peace Point ( ) Example 8: Recession Curve Method, Mackenzie River at Fort Simpson ( ) Example 9: Recession Curve Method, Hay River at Hay River ( ) Example 10: Effective Gauge Height Method, Nith River near Canning ( ) Example 11: Effective Gauge Height Method, Peace River at Peace Point ( ) Example 12: Modified Backwater Method, North Saskatchewan River at Prince Albert ( ) Example 13: K Factor Method, Nith River near Canning ( ) Example 14: K Factor Method, Peace River at Peace Point ( ) iv

133 1.0 PURPOSE AND BACKGROUND Stream discharge data are collected during the winter period at many locations throughout Canada. Since most rivers are either partially or completely ice covered during this period, the technician must learn the various procedures for computing discharges under ice conditions. It is particularly important for the technicians to be fully familiar with the various methods of computation so that an informed choice of the method of computation can be made to satisfy the computations at any given station. I. This lesson package discusses manual computations. (Computer applications will be covered in a later lesson.) Examples are provided, but the instructor may add examples from his own files, audiovisual aids and other relevant material. National standards are now being developed for daily discharge computations during ice periods. Section a, of the Manual of Hydrometric Data Computation and Publication Procedures states : Because of the many variable factors involved, no single standard procedure is suggested for the computation of daily discharges during periods when the stage-discharge relation is affected by the presence of ice. Several methods of computing discharges under ice conditions are available and it is suggested that the Regional Offices use the method that best suits each individual station. II. This lesson does not cover the interpretation of gauge records during periods of freeze-up and breakup. These two transition periods are generally short in duration but can represent a large portion of the annual runoff. These two periods are often the most difficult ones for which to produce reliable estimates, even for seasoned hydrometrists, who must use ingenuity, experience, and a knowledge of the characteristic traits that indicate transition. These two periods should be discussed in detail in a future edition of this lesson package. Computation under ice conditions involves a high level of personal judgement on the part of the technician in the interpretation of the available data. Therefore, some knowledge of the physical processes of ice forming, growing, breaking up, and melting is essential. The greater this knowledge, the more confidence can be placed in the computations and the ensuing records. Since the reading required to obtain this knowledge is not part of the formal classroom instruction, it should be done by the participant on a supplementary basis. The bibliography in the lesson package is for convenience and guidance, but should not be regarded as complete, and should be augmented by the users as additional material comes to their attention. Experience and knowledge of local conditions are also important considerations in the production of reliable discharge records during ice periods. For this reason the instructor should provide examples from his own area. The methods used for computing discharges under ice should be documented on the station analysis form. The following quotations from the National Handbook of Recommended Methods for Water Data Acquisition are so appropriate to this lesson that they deserve to be included to emphasize the considerations that must be given to computing discharge data under ice conditions. Ice Formation and Melting Ice at the control may affect the normal stage-discharge relations. Its effects vary with the quantity of ice and its nature whether surface ice, frazil, or anchor ice. Ice may also affect the stage-discharge relation if it forms a jam in the channel below the control sufficient to cause submergence of the control, or if it forms or collects between the gage and the control in sufficient amounts to cause additional resistance to flow, thus changing the slope of the water at the gage. The magnitude of the effect of ice on the stage-discharge relation the backwater caused by ice may be determined by measuring the discharge, observing the 1

134 corresponding stage, and computing the difference between the observed stage and the stage for the measured discharge corresponding to the open-water stage-discharge rating curve. Such a procedure is based on the assumption that the open-water control remains permanent with respect to its physical features during the time when the stage-discharge relation is affected by ice. This assumption is generally true of streams of fairly stable beds and banks except for such scouring as may occur during the period of ice break-up, which is generally accompanied by high stages and correspondingly high velocities. Complete ice cover at the control and for some distance upstream may, in some instances, produce a closed conduit in which the characteristics of flow are different from those that prevail in a normal open-water channel. Ice cover increases the frictional resistance to flow by the additional resistance introduced by the surface of the ice that is in contact with the flowing water. Also, the increase in the length of wetted perimeter causes reduction of the hydraulic radius. As a result of these changes in hydraulic conditions, a greater effective slope is needed for the same discharge. Many studies have been made to determine the effect of ice on the open-water ratings of a stream that is completely covered with ice for long reaches of channel except for a short distance at the rapids or riffle of the low-water control. These studies have shown in general that if the gage is located reasonably close to the control the presence of ice cover above or below the open control has little, if any, effect on the open-water stage-discharge rating. However, when the channel is partly or completely covered with ice at the control, the amount of backwater for a given stage will increase with the amount and thickness of ice and with the amount of snow on top of the ice which may, by its weight, cause additional displacement of water. Ice may form so gradually that there may be little to indicate the time when the stage-discharge relations began to be affected. On the other hand, a decided rise in stage caused by an ice obstruction or a sharp drop in stage caused in part by impounding of water in the form of ice and in part by channel storage above the gage at places where ice has retarded the flow, may be the first indication that the stage-discharge relation is affected. On small streams in which a large part of the winter flow is derived from ground-water, it is not uncommon for the minimum flow of the year to occur just after the first extremely cold period, when the discharge from ground water is temporarily checked. Under such conditions, if water is being impounded above the gage in the form of ice and channel storage, a period of extremely low flow may occur, which will usually be followed by a partial recovery. If a continuous record of the stage is made by a water-stage recorder, a steeper slope of the graph on a falling stage than on a rising stage usually indicates that the stagedischarge relation is affected by ice. Of the three varieties of ice surface, frazil, and anchor surface ice is the most common and its effect is evident at more gaging stations than either of the other two. Although the different kinds of ice often occur in combination, each one by itself will produce the same general effect on the stage-discharge relation, that is, an increase in stage above that of normal open-water conditions. The major stream-gaging problems that result from any form of ice are related to the amount of backwater and its variation from day to day and the length of time when the stage-discharge relation is affected. (pp and 1 98). Effects of Backwater or Ice Usually the effects of backwater and/or ice make the reliability of the published and computed record inconsistent and somewhat suspect. Backwater from ice, vegetation, changing control, beaver activity, dune and riffle formation, or jamming or tributary inflow, complicates record processing. A rational method of evaluating the relative affects of changing backwater for all situations is not possible. Each occurrence is unique and must be handled and processed according to the situation and its merits. Common sense and experience provide the only reliable methods and/or rationale that can be recommended for use. The loss of record due to ice in the well, the float frozen in ice, frozen intakes, etc., is a totally different problem than backwater from ice. The use of weather records, hydrographic comparison of records of flow upstream or downstream or on similar drainages in the area, or calculation of ground water effluent to the stream, are 2

135 reliable and consistent methods for estimating flow during periods of missing record and for computing the relative backwater from ice during a period of recorded gage height. Documentation of ice and/or backwater conditions in the field by field personnel adds immeasurably to confidence one places in the data. (p ). 3

136 2.0 OBJECTIVES This lesson package has been designed to enable the technician to do the following : explain the formation of ice in rivers and the effect the ice has on the stage discharge relationship compute daily discharges under ice conditions, using a variety of manual methods adopted by the Water Resources Branch explain the factors affecting the reliability of the results interpret conflicting situations, where more than one factor may affect the computations. 4

137 3.0 INTRODUCTION The participants should review the terms and definitions listed in Appendix A before proceeding with this lesson package. This lesson package describes seven manual methods of computing daily discharges under ice conditions. These seven methods are the most commonly used. This lesson package will not cover computer modelling. The seven manual methods are : 1. backwater method 2. adjusted discharge method 3. interpolated discharge method 4. recession curve method 5. effective gauge height method 6. modified backwater method 7. discharge ratio or K factor method. Section 5.0 describes these methods in detail, and examples are contained in Appendix C. 5

138 4.0 GENERAL CONSIDERATIONS 4.1 EFFECT OF ICE ON THE STAGE DISCHARGE RELATION This section is modified from pages 360 to 367 of Rantz et al. (1982) Introduction The discussions found herein refer to the gauging station locations exclusively, although the principles of ice effect apply anywhere along the streams. The formation of ice in streams or on section controls affects the stage discharge relationship by causing backwater that varies in effect with the quantity and nature of the ice as well as with the discharge. This section describes three types of ice formation, and their typical effects on the stage discharge relationship. The three types are : frazil, anchor, and surface ice Frazil Ice Frazil ice is in the form of fine elongated needles, thin sheets, or cubical crystals, formed at the surface of turbulent water (e.g. riffles). The turbulence prevents the crystals from coalescing to form sheet ice. The crystals may form in sufficient numbers to give the water a milky appearance. When crystals float into slower water they come together to coalesce into masses known as slush ice. Uninterrupted flow of frazil or floating slush ice has no effect on the stage discharge relation. When the current carries slush ice under a sheet of downstream surface ice, the slush may become attached to the underside of the surface ice, thereby increasing the effective depth of the surface ice. Most of this slush that adheres to the surface ice does so near the upstream end of the ice sheet. Interrupted flows can occur when frazil and slush ice gather where a sheet of solid ice has formed, at sharp river bends, in shoreline debris, etc. Frazil and slush ice are generally easily transported because the ice will separate to flow around obstructions. In these instances the backwater effect is small. When slush and frazil ice are heavy and are interrupted, the amount of backwater created can be quite large. In the first instance, small amounts of backwater are of fairly short duration. In the second instance, and if there is a constant supply of frazil and slush ice from upstream, the backwater conditions can last for a long period of time Anchor Ice Anchor ice is an accumulation of spongy ice or slush adhering to the rocks of a streambed. Anchor ice generally forms on clear cold nights on the streambeds of open reaches of river. In the past, the theory was that anchor ice resulted from loss of heat by long-wave radiation from the streambed to outer space. This theory has proved to be invalid because all of the long-wave radiation that can be lost from the streambed at 0ºC would be absorbed in less than 1 cm of water. Anchor ice is either : 6

139 1. frazil carried by turbulent currents to the streambed where the ice adhered to the rocks, or 2. ice that formed as the result of supercooled water crystallizing on nucleating agents on the streambed. Rocks act as a nucleating agent for the continued growth of the ice mass. Regardless of how anchor ice forms, it cannot form or exist when shortwave radiation from the sun penetrates the water and warms the rocks. When the morning sun strikes anchor ice that formed the night before, it warms the streambed. The anchor ice is released and floats to the surface, often carrying small stones that it has picked up from the bed. For the next few hours, the stream will be full of floating slush released in a similar manner upstream. Anchor ice on the streambed or on the section control may build up the bed and (or) control to the extent that a higher than normal stage results from a given discharge. The solid-line graph in Figure 1 shows a typical effect of anchor ice on a water stage recorder graph. The rise starts in late evening or early morning, many hours after the sun has set, when ice begins to adhere to the rocks and raises the water level. By 10 a.m. the sun has warmed the streambed sufficiently to release the ice and the stage starts to fall. The distinguishing feature of the anchor-ice hump is that the rise is slow compared to the fall. The small rises in actual discharge in the late afternoon, shown by the short-dashed lines in Figure 1, probably result from water being released from channel storage when anchor ice upstream is freed. There may also be some runoff from the melting of snow and ice during the warmer part of the day. Figure 1: Gauge chart showing typical anchor ice humps (After Rantz et al., p. 362) Surface Ice As the name implies, surface ice forms on the surface, first as a fringe of shore ice. Then, if the stream is not too turbulent, the surface ice spreads to form a continuous ice cover spanning the stream from bank to bank. A description of the formation of surface ice follows. With the onset of cold weather, the water in a stream is gradually cooled. Along the banks where the water is quiescent, temperature stratification occurs as in a lake. Because depths near the bank are usually very shallow, temperatures reach the freezing point more quickly there. Ice crystals form and adhere to the banks, twigs, and projecting rocks. A thin ice sheet forms. In the open part of the channel, temperature stratification is generally absent because of turbulent mixing, and the entire water body must reach 0ºC before any freezing will occur. In the absence of nuclei or foreign material on which the ice crystals may form, there may be slight supercooling of the surface layer before any ice crystals are produced. The ice sheet builds out from the shore as supercooled water, or water carrying ice crystals, impinges on the already-formed shore ice. The transported or newly formed ice crystals adhere to the sheet. In the centre of the stream, turbulence prevents coalescence of the ice crystals (frazil) that form. In the less turbulent areas, groups of crystals coalesce to form small pans of floating slush. These pans and individual ice crystals are carried by the currents until they too impinge and adhere to existing ice sheets. In this manner, an ice sheet finally forms across the entire stream. The ensuing increase in thickness of the ice sheet occurs almost entirely where the ice and water meet. The floating pans flow downstream until they jam at a bend or channel constriction and back up the following pans until a solid cover is formed. 7

140 Surface ice, when in contact with the stream, may in effect change the streamflow from open-channel flow to closed circuit flow. Frictional resistance is increased due to the ice layer. The cross-sectional area of the flowing water is decreased. Given constant flows in a channel, the increase in frictional resistance and the reduction in the cross sectional area indicate a higher gauge height (see Figure 2). The recorded gauge height is the result of the equivalent open water gauge height plus the backwater due to ice. Figure 2. Gauge chart showing typical rise as complete ice cover forms (After Rantz et al., p. 364) Surface ice formation generally creates a gradual increase in backwater. As the water level trace increases so does the backwater. These trends continue until there is a change in the climate. Surface ice can also cause siphon action when it forms on a section control. In Figure 3, when water fills the entire space between the control and the ice, siphon action begins and water flows over the control faster than it enters the gauge pool. The gauge pool is pulled down below the point of zero flow before air enters the system and breaks the siphon action. Discharges decrease to no flow and then become a trickle while the inflow fills once more and the siphon action begins again. Siphon action is easily recognizable from the rapid fluctuations of the stage record. If the field officer visits the gauging station at that time, he or she should take the discharge measurement far enough upstream from the gauge pool to be unaffected by the fluctuating pool level. Figure 3: Effect of siphon action at artificial control (After Rantz et al., p. 365) If the section control is open and the gauge is not too far removed from the control, there will probably be no backwater effect, even though the entire pool is ice covered. The only effect the ice cover will have on the flow will be to slow up the velocity of approach, and this effect will probably be minor. If the gauge, however, is a considerable distance upstream from the riffle, surface ice on the pool may cause backwater as the covered reach of pool becomes a partial channel control. Ice that forms below an open-section control may jam and raise the water level enough to introduce backwater effect at the control. Where discernible by a measurement or from the chart trace, backwater due to frazil or slush ice will be computed in the same way as for surface ice. 8

141 4.1.5 Computation of Discharge during Periods of Anchor Ice Anchor ice rises are clearly recognizable on the recorder chart. When computing discharges for periods of anchor ice effect, make adjustments to the gauge height directly on the gauge height graph. In Figure 1, the long-dashed line connecting the low points of the anchor ice hump is the effective gauge height to use during the hours when the hump was recorded. Actually, the true effective gauge height is shown by the short-dashed line. As the anchor ice builds up, the flow decreases faster than the normal recession shown by the long-dashed line, because some of the flow is going into storage as a result of the increased stage. When the anchor ice goes out at about 9 or 10 a.m., a volume of water is released from storage and the true effective gauge height rises. However, the areas formed by the short-dashed lines above and below the long-dashed line balance. We would get identical daily mean values using either of the dashed lines. The rule, then, for obtaining effective gauge height during anchor ice periods is to cut off the hump with a straight line connecting the low points of the gauge height graph. In normal practice within the Water Survey of Canada (WSC), the effective gauge height is obtained as described above, i.e., a straight line is drawn on the chart to remove the water level rise caused by the build-up of anchor ice. This straight line then becomes the effective gauge height. When drawing the effective gauge height line care must be taken to recognize the formation completely covered with ice if it occurs. Should complete ice cover occur a continuation of the above method will nearly always produce more discharge than should be shown. Exercise 1 in (Appendix B) provides an opportunity to compute discharges under the above conditions Computation of Discharge during Periods of Surface Ice In Figure 4, the triangles show an example of how to plot discharge measurements during periods of ice effect on a stage discharge curve. Exercise 2 is an example of a gauge height graph as a complete ice cover forms. Exercise 2 shows that the backwater effect from surface ice cannot be determined directly from the recorder chart. However, the recorder chart is very helpful in determining which periods during the winter are affected by ice. The field officer's completed notes describing ice conditions during the station visit are also very valuable. Most important of all are the discharge measurements made during ice-affected periods. A discharge measurement will give a definite point of discharge value on a hydrograph. Figure 4: Stage discharge curve 9

142 4.1.7 Computing Daily Mean Discharges on Days Discharge Measurements Were Taken A variety of ice conditions can exist : frazil and slush ice, anchor ice, partial ice cover, complete ice cover, ice jams, flowing ice chunks, or a mix of the above. Detailed comments and sketches on the field notes will assist in determining daily mean discharges. There are three common methods for determining the daily mean discharge on days when discharge measurements were obtained. 1. If little change in stage occurred during the day the discharge measurement was made, consider the measured discharge to be the daily mean discharge. 2. If a significant change in stage occurred that day, and it is assumed this was caused by a change in discharge, compute the daily mean discharge (Q) from the formula : Q = Q a (Q m Q r ) where Q a = the discharge from the open-water, ice-free stage discharge curve corresponding to the daily mean gauge height Q m = the measured discharge Q r = the discharge from the open-water stage discharge curve corresponding to the gauge height of the discharge measurement. 3. In the case where a uniform stage change occurs, compute the daily mean discharge (Q) by first determining the backwater shift at the time the measurement was taken. Then apply this shift to the mean daily gauge height and obtain an effective gauge height. The discharge corresponding to the effective gauge height represents the mean discharge for the day. The assumption here is that there was little or no change in backwater for the day. Append the symbol B to discharges affected by ice. This denotes an estimate of discharge during a period when the stage discharge relationship was affected by ice conditions. It is possible although rare that a positive shift will be calculated. This can happen when ice is quite solidly frozen to the banks of fairly small streams, and there is a relatively small increase in the discharge. The channel acts as a closed conduit or pipe, and there is insufficient flow to break or lift the ice. The velocity will increase due to the head built up upstream of the gauge. 10

143 4.1.8 Example Exercises The participants should complete exercises 1, 2, and 3 in (Appendix B) at this time. These exercises demonstrate how the effective gauge heights can be determined from the recorder chart. Exercise 3 begins with effective gauge heights but because of the way ice formed, the discharges were also determined by hydrograph comparison. Copies of charts, field notes (for exercises 2 and 3 only), stage discharge tables, form , and a monthly meteorological summary are supplied. A copy of the discharges approved for publication is included to check the participant's work. Exercise 1 Oxtongue River Near Dwight This is an example of anchor ice. Estimate the effective gauge heights for December 26 30, 1987, and compute the mean daily discharges using stage discharge table No. 3 on the blank form Exercise 2 Humber River at Weston In this exercise, a discharge measurement was obtained on January 15, 1987, under open-water conditions. The notes on the chart indicate the formation of ice from minor slush to continuous ice cover. Using stage discharge table No. 28, complete the mean daily discharges from January 16 to 23, 1987, on the blank form Exercise 3 Lynde Creek near Whitby The discharge measurement indicates that there is significant backwater due to ice. The control is submerged. There is lots of ice in the middle of the channel and ice is thin. Compute the mean daily discharges from March 12 to 18, 1987, using stage discharge table No. 16 on form

144 5.0 METHODS OF COMPUTATION 5.1 INTRODUCTION During its history, the Water Survey of Canada has employed a number of methods to compute the discharge in ice-affected streams. Because of the wide variety of climatic conditions and streamflow regimes in Canada, streams or streamflow conditions are not classified in any particular computational method. The method used will depend upon the quantity and quality of hydrometric and meteorologic data and on knowledge of historical ice-affected flows at the gauging site. This chapter outlines a number of methods that should be tested in computing hydrometric data. The technician can select the method or combination of methods that gives the best apparent result. The following seven methods will be elaborated on here : 1. backwater method 2. adjusted discharge method 3. interpolated discharge method 4. recession curve method 5. effective gauge height method 6. modified backwater method 7. K factor method. Not all of these methods are suitable at all sites Methodology The approach to computing discharges under ice conditions should be very systematic. Technicians must strive to compute records for individual stations before beginning any qualifying of these computations. The systematic approach requires that the following preparations be made and that the selected computation methods described later be used with the quality checking of the computations coming last. This will ensure unbiased determination of discharges under ice based on the collected field data. The systematic approach will also point out shortfalls in the data collection process, which can then be addressed in the field program Preparation From a practical point of view, it may be necessary to revert to obtaining some of the required basic information from computer printouts (i.e. daily gauge heights and discharges). The technician should ensure that the gauge heights are corrected, using gauge corrections where required, and that the open-water equivalent discharges have been corrected, using shifts where control changes have occurred. For the purposes of this lesson the technician should copy the gauge height and discharge values onto the appropriate forms before proceeding with computations, and obtain and assemble all available records and necessary forms. These may include the following : 1. Daily gauge height record on form (or F) duly completed as per instructions in Lesson Package No

145 2. Recorder chart and/or records of manual gauge readings (usually in gauge books) for the appropriate period. These books often contain useful information, including weather conditions and sketches of ice conditions at the gauge section and the control. This information is especially useful in periods of unstable ice conditions, i.e. freeze-up and breakup. 3. Discharge measurement field notes (form IW 2078A) for all discharge measurements during the period of interest. 4. Completed list of discharge measurements (form M). 5. Current stagedischarge table (forms M and M). 6. Completed discharge hydrograph for year to date. When carrying over an ice period from the previous calendar year, transfer the discharge hydrograph for December of the previous year onto the hydrograph of the current year to ensure continuity of record, and continue computations into the following year's records wherever possible. 7. Records of contributed data such as discharges from dams and power houses, manipulation of flows by river control authorities, etc. 8. Any other available records or data. The technician should also obtain the following information : 1. Temperature (daily maximum and minimum) and precipitation records (especially for southern stations) for locations nearest to the gauge from Atmosphere Environment Service and other sources such as provincial agencies and universities. Temperature records are used in all the methods of computations. Precipitation records are required when midwinter thaws and rain occur. Water flowing over the ice cover during a thaw is also a condition that needs to be considered when using these records. 2. Winter daily discharge records from nearby comparable stations. These are used in fitting the daily discharge hydrograph at the subject station when using the interpolated discharge method. Daily discharge records are also used for final verification of computations at the subject station. This can be done as a numerical comparison of flows (as would be the case in comparing flows within a large drainage basin) or as runoff over comparable drainage areas. Snowfall does not contribute to immediate runoff but could be a consideration in fitting the backwater hydrograph in the backwater method, as added weight on the ice cover. These records might be useful in estimating runoff and thence discharge in a partial thaw or complete breakup. 5.2 BACKWATER METHOD Introduction The backwater method utilizes the measured amount of backwater to define a backwater graph drawn coincidentally with the maximum and minimum temperatures and the daily mean gauge heights. The daily mean discharges are computed by subtracting the backwater as observed on the graph from the daily mean gauge heights. This method is most suitable where the streams are quite large, i.e., where the ice is normally fully supported by the water and floats up and down with gauge height changes. 13

146 This method requires four known values : 1. the winter discharge measurements 2. the related gauge reading for the measurements 3. the mean daily gauge heights for the period being computed 4. the open water stagedischarge curve. In Figure 5 backwater effect refers to the difference between the gauge height (H B ), as read at the time of the measurement, and the stage that would occur for the measured discharge if open water conditions existed (H E ) Graph Preparation Examples 1 and 2 (Appendix C) illustrate graph preparations. 1. The measured backwater effect and a graph of the maximum and minimum daily temperatures are plotted against time. 2. A backwater hydrograph is then drawn through the measured points using the temperature graph for reference. The recorded daily gauge heights should also be plotted on this graph sheet as a further guide to positioning the backwater hydrograph. Figure 5: Illustration of backwater effect 3. The technician then computes the daily effective gauge heights by subtracting the daily backwater effect (as indicated by the backwater curve) from the recorded daily gauge heights. These daily effective gauge heights are applied to the open water rating curve to produce daily discharges. During periods of freeze-up and breakup, gauge charts should be examined for spikes and other anomalies that may indicate occurrence of ice-related phenomena such as ice jams and frazil accumulations. The technician should consult the gauge book, if available. The following blank forms will be needed in the computations : backwater computations or winter hydrograph sheets (natural or 2 cycle semi-logarithmic) or hydrograph sheets (natural). 14

147 Before making a backwater assessment, it may be preferable to draw an interpretation of the effective gauge height on a copy of the recorder chart and compute the backwater from this line (i.e., apply the method in reverse). The technician requires an in-depth knowledge of ice processes and conditions at the subject stations to interpret gauge records during freeze-up and breakup. The basic criterion for the backwater method is that the values of backwater remain fairly consistent and/or are gradually distributed throughout the period. Minor deviations are expected when temperature and precipitation records come into play. The following instructions, quoted from the Manual of Hydrometric Data Computation and Publication Procedures (section b), are in fact step-by-step instructions on using the backwater method. i. For each ice-affected discharge measurement enter on form the gauge height and discharge (from form ) and the effective gauge height and backwater as computed from the stagedischarge table. To ensure continuity in the backwater interpretation, enter these data also for the last measurement before the beginning of the ice period and for the first measurement after the end of the ice conditions. ii. iii. Transfer any pertinent remarks from the observer's record, measurement notes, weather records, etc., to the Remarks column of form These remarks should be of assistance in providing a basis for backwater interpretations. Transfer the daily gauge heights from form to the Daily Gauge Height column in form iv. Arrange the scales on a winter hydrograph form or equivalent, to allow for plotting of the following : 1. maximum and minimum (or mean) temperatures, 2. backwater, 3. gauge heights (both daily and effective), and 4. discharge. v. Plot the following on form : 1. daily maximum and minimum (or mean) temperatures obtained from the appropriate meteorological station, 2. the gauge height and discharge from each discharge measurement and the effective gauge height and backwater correction as computed from the stagedischarge table (from form ); vi. circle these plotted points, and 3. the daily gauge heights. Draw the backwater graph on form The method of drawing this backwater graph will probably vary with each gauging station and will be dependent upon such factors as : 1. formation, storage and release of slush, 2. rate of ice formation, 3. temperature, 15

148 4. precipitation, 5. ice-jamming, 6. amount of snow cover, etc. vii. Transfer the daily backwater corrections from form to form and compute the effective gauge heights; compute the discharges corresponding to these effective gauge heights. viii. Plot the effective gauge heights and the corresponding discharges on form ix. The discharge hydrograph for an adjacent station may be plotted for comparison purposes. Certain previous interpretations may be changed to make the discharges appear more consistent. However, in trying to make the records appear more consistent, do not overlook the possibility that there may be some valid reason for the apparent inconsistency. x. Transfer the daily discharges from form to form To check the results of the backwater methods : 1. review the values of backwater 2. overlay the hydrographs 3. check the peak and recession values in terms of runoff over the drainage basin. Where discharge measurements are made frequently during the ice period, it may be unnecessary to plot a winter hydrograph. The computation of the daily discharges then may be made directly on form M. Examples 1 and 2 in (Appendix C) illustrate the backwater method. Example 2 includes only forms and simulations of forms or Example 1 includes all forms involved in the process, from the list of discharge measurements (form ) to the final transfer of data onto form ADJUSTED DISCHARGE METHOD Reference : Unknown. This method requires exactly the same observed information on the Backwater Method. Equivalent open-water discharges are obtained by using the waterlevel readings under ice conditions and the open-water stagedischarge curve. A hydrograph of equivalent open-water discharges are plotted below it on the appropriate days. The winter discharges are then estimated by joining the plotted measurement points, using the equivalent open-water hydrograph and temperature records as guides. This method, like the backwater method, requires the following known values : 1. discharges as measured 2. mean daily gauge heights 3. open water rating table (stagedischarge curve) The procedure is completed as follows, using backwater computation form and winter hydrograph form or

149 1. Enter the daily mean gauge heights. 2. Enter the measured discharges. 3. Enter the equivalent open-water discharges in a hand drawn column to the left of number 1 above. 4. Plot the equivalent open-water discharges on one of the winter hydrograph forms, making sure to include periods of open water at both ends of the ice period. 5. Plot the measured discharges on the winter hydrograph. 6. Review the measured discharges to see if these will represent the mean discharge for that day. If not, compute and/or decide what discharges will be used for the days the measurements were taken. This step needs careful consideration, especially when flow conditions change significantly during the day. 7. On the winter hydrograph fix any other points of known daily mean discharges available. 8. Using hydrographs from other streams and temperature and precipitation records that are deemed appropriate, indicate on the winter hydrograph the days on which peaks and lows occurred. 9. Decide on the magnitude of discharges for the points in 8 above. 10. Draw in the estimates of discharge for the remainder of the ice period on the winter hydrograph. 11. The estimated daily discharges are then transferred to the right-hand column on form This method is not complete without a check on the estimates of discharges. To check the results of the adjusted discharge method, compare the estimates to previously accepted comparable computations by : 1. overlaying the hydrographs 2. checking the peak and recession values in terms of runoff over the drainage area 3. completing the second and third right-hand columns (shift and effective gauge height) through selected portions of the hydrograph. These portions must include all extreme changes, the start or buildup of backwater and the breakup period. This step will then allow evaluation of the backwater derived as in the backwater method. 5.4 INTERPOLATED DISCHARGE METHOD This method can be used when only discharge measurements are available. This method is also suitable for estimating daily mean discharges for open water periods. Reference : Unknown. This method requires only the measured discharge and auxiliary information such as temperature at a nearby meteorological station and discharge measurements in nearby streams. The measured discharges during the winter are plotted on the appropriate dates, and a hydrograph of daily discharge for the winter season is drawn by joining the plotted points, using temperature records and any other supplemental information, such as flow in adjacent streams, as a guide in shaping the hydrograph. Reference : Manual of Hydrometric Data Computation and Publication Procedures, section d i. Enter on form the measured discharges obtained during the ice period and any pertinent information which may be of value when drawing the daily discharge graph. ii. Plot the following on Winter Hydrograph form : 17

150 1. the daily maximum and minimum (or mean) temperatures obtained from the appropriate meteorological station, 2. the measured discharges (circle these plotted points), and 3. the discharge hydrograph for an adjacent stream, if available and if desirable. iii. Draw a daily discharge graph using a hydrograph for an adjacent stream, the temperature plot and other pertinent information as a guide. iv. Transfer the daily discharges from form to form v. Transfer the daily discharges from form to form vi. If desirable, the use of form may be eliminated in this method and the daily discharges transferred directly from the winter hydrograph to form Examples 5 and 6 in (Appendix C) illustrate this method. 5.5 RECESSION CURVE METHOD Reference : Unknown. Slopes of mean recession curves for various periods of the winter season are estimated from a study of open water recession curves at the station and from winter measurements over the period of record. The curves are then plotted on semi-logarithmic paper, and the measurements for the winter study are plotted on the same chart (semi-log paper). The discharge hydrograph for the winter is constructed by drawing a curve through the plotted points, using the recession curves and temperature records as guides. Recession constants may be effective in estimating the winter record on large rivers where the flow is derived almost entirely from groundwater depletion or lake releases. There may be slight flow reductions from ice choking off small inflow streams and slight increases from the weight of the snow on the ice of large lakes but the base flow would predominate. The method would not be applicable during freeze-up or breakup conditions because of variable flow conditions. A recession constant indicates the reduction of flow from one day to the next. In the equation that follows, the example shows that the January 2 flow will be 97% of the January 1 flow, and the January 3 flow will be 97% of the January 2 flow, etc. The recession equation is : Q 2 = Q 1 K t where Q 2 = discharge at time t 2 Q 1 = discharge at time t 1 K = recession constant for a unit of time t = elapsed time interval (t 2 - t 1 ) For example, if the flow on January 1 (Q 1 ) is 1250 cfs and the recession constant (K) to be applied is 0.97, the flow on January 15 is 816 cfs by : 18

151 Q 2 = 1250 x = 1250 x = 816 In computing daily values of K, t becomes 1 if the computations progress from one day to the next (e.g. Jan. 1 to Jan. 2 = 1 day) or if progressing in large blocks of time (e.g. Jan. 1 to Jan. 15 = 14 days). Therefore : t = 1 or 14 Since we are dealing with a recession, the values of K will always be less than 1. On a daily basis where t = 1 the flows for January 2 will be the flows of January 1 X K. The constant K should be developed by examining periods of recession of open water flows that simulate winter flow conditions, i.e. ones in which the water supply is almost entirely from groundwater depletion or lake release. A study of past events must be undertaken to compute various values of K for different recession rates. These results are then plotted to produce recession equations and curves. To calculate the recession one requires two flow values and a measure of the time interval between them. The equation is : K = (Q 2 Q 1 ) 1 t When a continuous series of daily flow values is available, Q 2 follows Q 1 by one day, and the equation becomes : K = (Q 2 Q 1 ) The recession equation, Q 2 = Q 1 K t can be expressed in another form, in which the constant that defines the recession characteristics is k. The equation is : Q 2 = Q 1 e - t/k (i.e. Q 1 times to the power - t/k ) and k (usually in units of days) is the length of time required for the flow to reach 1/e or 36.8% of its original value. Comparison of the equations shows that : K = 3-1 k The curves and equations are then fitted to the period of record to be estimated. The governing criteria for selecting a particular curve and equation will be the rate of recession over the period to be estimated and the fit of this curve through available discharge measurements. Since the recession can be defined mathematically as an exponential equation, the base flow plots as a straight line 19

152 on a semi-log plot of discharge versus time. This means that blank periods on a log discharge hydrograph can be completed by filling them in with a straight line following the same criteria as for the mathematical method. Because of the fact that the typical rating curve is generally a logarithmic relationship, the filling in of a short blank period with a straight line interpolation on the stage record maintains the smooth recession curve of the discharge. This is applicable when the stage hydrograph slope is smooth and similar at both ends of the blank period, as shown in Figure. 6. Examples 7, 8, and 9 show the use of recession curves. The recession curve will not be applicable during conditions of retention and release of water into and out of storage while the ice cover is forming, or breakup time because of inflow from snowmelt and the storing and releasing of water due to ice jams. Figure 6: Illustration of recession hydrograph Other means of estimating or interpolation will have to be used at these times. A temperature graph is very important during freeze-up and breakup because it indicates unsettled conditions as well as periods when inflow or ice jams may be occurring at breakup. By plotting a graph of the gauge height record during these periods, you can estimate when the breakup occurred. Methodology 1. Plot the winter measurements on semi-log paper (logarithmic hydrograph paper). 2. Join the measurements to produce a smooth curve. Use previous years' recession curves to help sketch the present year curve. 3. Determine when the flow following freeze-up has stabilized itself and before breakup or inflow occurs in the spring. 4. Pick discharges for each day directly from the recession line drawn on the hydrograph and use as daily discharge for the period you are estimating. If a measurement has been obtained in mid or late November, only a short period of time elapses until freeze-up occurs. Use a straight line interpolation or the backwater method for this period. During the spring breakup, any method is just a calculated guess. Two stations that seem well suited to the recession curve method are : 1. the Hay River at Hay River, and 2. the Mackenzie River at Fort Simpson (examples 8 and 9 in Appendix C). The Peace River is a poor example and should not be computed by the recession method, as can be seen from Example 7. If no discharge measurements are available, it may be possible to develop a recession curve by the following technique from Methods for the Estimation of Hydrometric Data, section 7.2 (illustrated by Figure 7). (Discharges from the recession curve can be entered directly onto form (or F). Form is not required.) 20

153 The recession constant method is also useful when estimating a long period of record of several months that is void of significant rainfall and where two or three discharge measurements are available. In this case, the recession constant is calculated from other periods of historical records for the station. A recession curve may also be developed by plotting values of Q 2 against Q l some fixed time t later. Normally a curve indicating a gradual change in the value of K results. This curve approaches a 45 line as Q approaches zero. The recession curve for the Churchill River above Otter Rapids is illustrated in Figure 7. This method may be used to construct recessions for base flow or direct runoff. For base flow recession, data should be selected from periods several days after the peak of a flood so that it is reasonably certain that no direct runoff is included. After the base flow recession has been established, it can be projected back under the hydrograph immediately following a flood peak and the difference between projected base flow and the total hydrograph used to develop a direct runoff Figure 7: Recession curve for Churchill River above Otter Rapids recession curve. The base flow curve should be drawn to envelop the plotted data on the right because such a curve represents the slowest recession (high K). Conversely, data for the direct runoff recession are enclosed on the left [in Figure 7]. 5.6 EFFECTIVE GAUGE HEIGHT METHOD Reference: Unknown For this method a hydrograph of the observed daily water levels is constructed. 1. An effective stage for the time of each discharge measurement is computed from the observed stage, the measured discharge, and the open-water stagedischarge relation. 2. The effective stage for each discharge measurement is then plotted below the stage hydrograph. 3. A curve of the daily effective water levels for the seasons is then produced by joining the plotted points, using the hydrograph of observed water levels as a guide, as well as the temperature records. 4. Mean daily discharges are calculated by applying the open-water stagedischarge curve to the effective stage. The following forms are needed for this method : 1. form M backwater computations 2. form winter hydrograph (natural scale) 21

154 3. daily water level records extending beyond the period to be computed 4. discharge measurements taken during the period to be computed 5. the current open-water stagedischarge relation. Methodology 1. Construct a hydrograph by plotting the gauge heights. 2. Compute the effective gauge height for each discharge measurement from the observed gauge height, the measured discharge, and the open-water stagedischarge relation. Plot these on the hydrograph. 3. Produce a curve of the daily effective gauge height for the season by joining the plotted points, using the hydrograph of observed gauge heights as a guide, with some reference to the temperature records. 4. Extract the effective daily gauge heights for each day to be computed from the hydrograph and enter these values on form M. 5. Look up the discharge equivalent to the effective daily gauge heights on the stagedischarge relation and enter these on form M as the computed daily discharges. The documentation for this method is essentially the same as for the backwater method (section 5.2). The only difference is that no backwater figures are entered on form M. Examples 10 and 11 in Appendix C illustrate this method. 5.7 MODIFIED BACKWATER METHOD The modified backwater method uses a relationship such that the backwater on any given day is a function of the equivalent ice-free discharge on that day and the discharge at freeze-up. This method requires : 1. the daily mean gauge heights for the period to be computed 2. the computed daily mean discharge at freeze-up 3. the discharge measurements for the period to be computed 4. form M backwater computations. The equation is : B = K log [(Q e Q i )] where B = backwater in appropriate stage units K = constant Q e = equivalent ice-free discharge from stagedischarge relationship Q i = discharge at freeze-up. 22

155 Methodology 1. Use the discharge measurements to compute the values of K in the relationship, i.e., let Qe in the equation represent the measured discharges. 2. Rearrange the equation so that : K = B [log (Q e Q i )] 3. Then, using the number of days between the discharge measurements, interrupt the value of K for each day, and enter these in a lined column on form M. 4. Using the initial equation B = K [log (Q e Q i )] 5. compute values of backwater (B) for each day and enter on form M. 6. Compute the effective gauge heights by subtracting the backwater from the daily mean gauge heights and enter on form M. 7. Determine the daily mean discharges by applying the stagedischarge relation to the effective gauge heights and enter on form M. This method suits streams with a stable ice cover and situations where measurements are done often enough to determine the value of K. This method can be automated, because it uses a formula. The method should not be used in early winter or near the spring breakup period, when ice conditions are variable. Example Computations of daily mean discharge under ice conditions for the North Saskatchewan River at Prince Albert. 1. Determine the value of the constant K from discharge measurements using 4120 cfs as discharge at freezeup. a. December 13, 1974 mean gauge height : 6.23 feet metered discharge : 4,120 cfs backwater correction : feet equivalent open water discharge : 8,350 cfs Therefore : K = B (log (Q e Q i )) K = (log (8,350 4,120)) = b. January 23, 1975 mean gauge height : 6.91 feet metered discharge : 4,900 cfs backwater correction : feet equivalent open water discharge : 10,700 cfs 23

156 Therefore : K = B (log (Q e Q i )) K = (log (10,700 4,900)) = c. March 05, 1975 mean gauge height : 6.93 feet metered discharge : 4,460 cfs backwater correction : 2.14 feet equivalent open water discharge : 10,700 cfs Therefore : K = B (log (Q e Q i )) K = (log (10,700 4,460)) = d. April 10, 1975 mean gauge height : 6.84 feet metered discharge : 3,800 cfs backwater correction : 2.36 feet equivalent open water discharge : 10,400 cfs Therefore : K = B (log (Q e Q i )) K = (log (10,400 3,800)) = Using 2960 as the discharge freeze-up e. December 15, 1975 mean gauge height : 5.54 feet metered discharge : 2,960 cfs backwater correction : 1.47 feet equivalent open water discharge : 6,360 cfs Therefore : K = B (log (Q e Q i )) K = (log (6,360 2,960)) = Distribute the value of K between discharge measurements. 3. Compute the backwater corrections using the formula : B = K [log (Q e Q i )] where Q i = 4,120 for the period January 1 to April 23 and 2,960 for the period November 21 to December Refer to backwater computation sheets, column Q e and B.W. correction. 24

157 5. Compute the effective gauge height from the daily mean gauge height and backwater correction (daily mean gauge height + backwater correction = effective gauge height). Refer to columns daily mean gauge height and effective gauge height on backwater correction. 6. Determine the daily mean discharge using the open-water stage discharge relationship and the effective gauge height. 7. Example 12, hydrograph I, shows the relation between the equivalent discharge and the discharge under ice conditions using the modified backwater method. 8. Example 12, hydrograph II, shows the relation between discharge determined by applying the backwater corrections from the measurements, and distributing them with respect to time, to the discharges determined by the modified backwater method for the period affected by ice. Example 12 is included in Appendix C. 5.8 K FACTOR METHOD This method is more aptly called the discharge-ratio method by the U.S. Geological Survey. A K factor is computed for each winter measurement, K being the ratio of the measured discharge to the equivalent open-water discharge at the same gauge height. This ratio is always less than one. This method is best suited where the backwater is reasonably predictable throughout the period. The following are required : 1. form M backwater computations 2. form or winter hydrograph 3. discharge measurements for the winter period 4. temperature and precipitation records. The equation is : Methodology K = Q m Q o where K = constant Q m = measured discharge Q o = equivalent open-water discharge at time of measurement 1. Compute the K constant for each discharge measurement. 2. Plot the K constants on form or Construct a discharge-ratio (K factor) hydrograph by joining the plotted points, using temperature records as a guide. 25

158 4. Enter the daily gauge heights. 5. Enter the daily equivalent open-water discharges in a ruled column on form M. 6. Extract the K factors for each day from number 3 above. 7. Compute the daily discharge for the winter season by multiplying the equivalent open-water discharge obtained from each day's gauge height by the corresponding K factor. The method is illustrated by examples 13 and 14 in Appendix C. 26

159 6.0 DOCUMENTATION I. Document the method used to compute and verify the daily discharge record for the winter season on the following forms and station analysis form : M (list of) discharge measurement M stage-discharge table (regular) and/or M stage-discharge table (expanded) M backwater computations winter hydrograph (natural scale, for backwater method) or winter hydrograph (2 cycle semi-log, for adjusted discharge, interpolated discharge, or recession curve method) M daily discharges (English headings) or FM daily discharges (French headings) hydrograph (semi-log scale, for calendar year). Note all the above forms except and are for a calendar year. As a winter season spans two calendar years, computations and review of the current winter season will be easier if you bring forward the documentation for the part of the season in the previous year. II. III. Photocopy the applicable forms. The required documentation is included in the examples with each of the methods in Section 5. You must indicate the symbol B opposite each day of each ice period on forms M and M (or FM). On form M enter the symbol in the Remarks column. On form M or FM enter the symbol to the right of the daily discharge figure. This symbol must be accompanied by an appropriate reference in a footnote, e.g., B = Ice conditions. The symbol B has precedence over the symbols A and E. Finally complete the station analysis form ( ). This form is also for a calendar year. You must document separately each part of the two winter seasons covered, unless you used the same computational method and reference hydrographs in both seasons. Instructions on the completion of this form are included in Lesson Package No. 22, Station Analysis Form. 6.1 QUALITY CHECKING OF COMPUTATIONS As was mentioned at the beginning of section 5.0, the final step after the computation of winter records at a station is to check the values by comparing with similar watersheds. Stations that are similar for comparison purposes will have been identified in previous years so an examination of the previous station analysis form should be all that is required. It may be worthwhile just to check and ensure that in previous years they did not miss stations that were contributed (such as reservoir stations or powerhouses) or stations in an adjacent technician's area (perhaps in another sub-office or region). 27

160 Comparing the data by overlaying hydrographs may reveal anomalies in the data at one of the stations, such as a poor measurement, an error in computations, or a false assumption. If no obvious error can be identified it may be assumed that the anomaly is justified and it should be documented and left as is. It is not necessary and possibly erroneous to make the hydrographs identical. Although this lesson package has only covered the manual methods of ice computations, there are programs available to assist in the quality checking. 1. The SAP 2 routine has options for plotting discharge or runoff values for several stations on the same plot, which makes comparisons much easier. 2. Mini-models have been written for some basins that have a number of stations on the same river or its tributaries, allowing tributaries to be summoned and log times applied. These computer programs are valuable tools for checking the quality of the data, but they must not be used as the means for the original computations. 28

161 7.0 SUMMARY This lesson package has described the manual procedures used by the Water Survey of Canada to compute daily discharge under ice conditions. It has reviewed the processes by which ice forms on rivers and has provided information on how ice affects stage discharge relations. The various methods of computation have been illustrated through examples and through several exercises. The applicability of each technique has been stressed as well as the need for quality checking. Technicians will require considerable practical experience to become proficient in data interpretation and computation under ice conditions. 29

162 8.0 MANUALS AND BIBLIOGRAPHY 8.1 MANUALS Environment Canada (1980), Manual of Hydrometric Data Computation and Publication Procedures, 5 th ed., Inland Waters Directorate, Water Resources Branch, Ottawa. Environment Canada (1984), Methods for the Estimation of Hydrometric Data, Inland Waters Directorate, Water Resources Branch, Ottawa. 8.2 BIBLIOGRAPHY Bucilla, D. (1980), Hydrometric Technician Training Program Manual, Water Resources Branch, Inland Waters Directorate, Environment Canada, internal document, Calgary. Jaffray, R.B. (1975), Ice Effects and Related Corrections to Winter Streamflows in Small Streams, Ontario Ministry of the Environment Water Resources Paper No. 6. Ontario Ministry of Natural Resources (1984), Ice Management Manual, Toronto. Rantz, S.E., et al. (1982), Measurement and Computation of Streamflow, Vol. 2, Computation of Discharge, U.S. Geol. Survey Water Supply Paper Rosenberg H.B., and Pentland, R.L. (1966), Accuracy of Winter Streamflow Records, Reprint, Water Resources Branch, Inland Waters Directorate, Environment Canada, Ottawa, United States Geological Survey (1977), National Handbook of Recommended Methods for Water Data Acquisition, Office of Water Data Coordination, Reston, VA. 30

163 APPENDIX A: EXERCISES BASED ON EXAMPLES EXERCISE 1: OXTONGUE RIVER NEAR DWIGHT Figure 8: Graphic Chart Figure 10a: Monthly Record Figure 9: Climatological Station Report Figure 10b: Monthly Record (continued) 31

164 Figure 11: Backwater Computations Form Figure 12: Backwater Computations Example 2 EXERCISE 2: HUMBER RIVER AT WESTON Figure 13: Hydrometric Survey Notes Figure 14. Level Notes 32

165 Figure 15. Figure 16. Figure 17. Figure 18: Monthly Meteorological Summary 33

166 Figure 19: Backwater Computations Form Figure 20: Backwater Computations Example 2 EXERCI SE 3: LYNDE CREEK NEAR WHITB Y Figure 21: Hydrometric Survey Notes Figure 22: Level Notes 34

167 Figure 24. Figure 23. Figure

168 Figure 26: Monthly Meteorological Summary Figure 27: Precipitation Occurrences Figure 28: Backwater Computations Form Figure 29. Backwater Computations Example 3 36

169 APPENDIX B: COMPUTATION EXERCISES EXAMPLE 1: BACKWATER METHOD, NITH RIVER NEAR CANNING ( ) Figure 31: Discharge Measurements (1983) Figure 30: Stage-Discharge Table (expanded) Figure 32: Discharge Measurements (1984) Figure 33: Backwater Computations (Dec. 1983) 37

170 Figure 34: Backwater Computations (Jan. 1984) Figure 35: Backwater Computations (Mar. 1984) Figure 37: Daily Discharges - Example 1 (10) Figure 36: Winter Discharge Computations 38

171 Figure 38: Daily Discharges - Example 1 (11) EXAMPLE 2: BACKWATER METHOD, PEACE RIVER AT PEACE POINT ( ) Figure 39. Computation of Daily Discharges (Nov. 1966) Figure 40: Computation of Daily Discharges (Dec. 1966) 39

172 Figure 42.: Winter Hydrograph Figure 41: Computation of Daily Discharges (Jan. 1967) EXAMPLE 3: ADJUSTED DISCHARGE METHOD, NITH RIVER NEAR CANNING ( ) Figure 43: Backwater Computations (Dec. 1983) Figure 44: Backwater Computations (Jan. 1984) 40

173 Figure 45: Backwater Computations (Feb. 1984) Figure 46: Backwater Computations (Mar. 1984) Figure 47: Winter Discharge Computations 41

174 EXAMPLE 4: ADJUSTED DISCHARGE METHOD, PEACE RIVER AT PEACE POINT ( ) Figure 48: Backwater Computations (Nov. 1966) Figure 49: Computation of Daily Discharges (Dec. 1966) Figure 51: Winter Hydrograph Figure 50: Computation of Daily Discharges (Jan. 1967) 42

175 EXAMPLE 5: INTERPOLATED DISCHARGE METHOD, NITH RIVER NEAR CANNING ( ) Figure 52: Backwater Computations (Dec. 1983) Figure 53: Backwater Computations (Dec. 1983) Figure 54: Backwater Computations (Feb. 1984) Figure 55: Backwater Computations (Mar. 1984) 43

176 Figure 56: Winter Discharge Computations EXAMPLE 6: INTERPOLATED DISCHARGE METHOD, PEACE RIVER AT PEACE POINT ( ) Figure 57: Computation of Daily Discharges (Oct. 1966) Figure 58: Computation of Daily Discharges (Nov. 1966) 44

177 Figure 59: Computation of Daily Discharges (Dec. 1966) Figure 60: Computation of Daily Discharges (Jan. 1967) Figure 61: Winter Hydrograph 45

178 EXAMPLE 7: RECESSION CURVE METHOD, PEACE RIVER AT PEACE POINT ( ) Figure 62: Hydrograph EXAMPLE 8: RECESSION CURVE METHOD, MACKENZIE RIVER AT FORT SIMPSON ( ) Figure 63: Hydrograph 46

179 EXAMPLE 9: RECESSION CURVE METHOD, HAY RIVER AT HAY RIVER ( ) Figure 64: Hydrograph EXAMPLE 10: EFFECTIVE GAUGE HEIGHT METHOD, NITH RIVER NEAR CANNING ( ) Figure 65: Backwater Computations (Dec. 1983) Figure 66: Backwater Computations (Jan. 1984) 47

180 Figure 67: Backwater Computations (Feb. 1984) Figure 68: Backwater Computations (Mar. 1984) Figure 69: Winter Discharge Computations 48

181 EXAMPLE 11: EFFECTIVE GAUGE HEIGHT METHOD, PEACE RIVER AT PEACE POINT ( ) Figure 70: Computation of Daily Discharges (Oct. 1966) Figure 71: Computation of Daily Discharges (Nov. 1966) Figure 72: Computation of Daily Discharges (Dec. 1966) Figure 73: Computation of Daily Discharges (Jan. 1967) 49

182 Figure 74: Winter Hydrograph 50

183 EXAMPLE 12: MODIFIED BACKWATER METHOD, NORTH SASKATCHEWAN RIVER AT PRINCE ALBERT ( ) Figure 75: K Value Figure 76. Backwater Computations (Jan. 1975) Figure 77: Backwater Computations (Feb. 1975) Figure 78: Backwater Computations (Mar. 1975) 51

184 Figure 79: Backwater Computations (Apr. 1975) Figure 80: Backwater Computations (Nov. 1975) Figure 82: Hydrograph (page 1) Figure 81: Backwater Computations (Dec. 1975) 52

185 Figure 83: Hydrograph (page 2) EXAMPLE 13: K FACTOR METHOD, NITH RIVER NEAR CANNING ( ) Figure 84: Backwater Computations (Dec. 1983) Figure 85: Backwater Computations (Jan. 1984) 53

186 Figure 86: Backwater Computations (Feb. 1984) Figure 87: Backwater Computations (Mar. 1984) Figure 88: Winter Discharge Computations 54

187 EXAMPLE 14: K FACTOR METHOD, PEACE RIVER AT PEACE POINT ( ) Figure 89: Computation of Daily Discharges (Nov. 1966) Figure 90: Computation of Daily Discharges (Dec. 1966) Figure 91: Computation of Daily Discharges (Jan. 1967) Figure 92: Computation of Daily Discharges (Feb. 1967) 55

188 Figure 93: Computation of Daily Discharges (Mar. 1967) Figure 94: Winter Hydrograph 56

189 THE WATER SURVEY OF CANADA HYDROMETRIC TECHNICIAN CAREER DEVELOPMENT PROGRAM Lesson Package No. 21 Annual Records W. Beranek Water Survey of Canada Environment Canada 75 Farquhar Street Guelph, Ontario Canada N1H 3N4 D.O. Anderson Water Survey of Canada Environment Canada Ottawa, Ontario Canada K1A 0H3

190 Copyright All rights reserved. Aussi disponible en français

191 TABLE OF CONTENTS 1.0 PURPOSE AND BACKGROUND OBJECTIVES DAILY COMPUTATIONS SIGNIFICANT FIGURES WATER LEVEL ONLY STATIONS STREAMFLOW STATIONS Daily Discharges Form ( ) Gauge Heights Shift Corrections Discharges Open Water Discharges Estimated under Ice Cover Discharges Estimated in Open Water SUBDIVIDED DAYS YEAR-END CONTINUITY EXERCISE COMPLETION OF THE DAILY DISCHARGES FORM MONTHLY AND ANNUAL SUMMARY EXTREMES OF STAGE AND DISCHARGE STAGE DISCHARGE TABLES ACCURACY STATEMENT SYMBOLS AND NOTES NOTES ON DATUM INITIALS APPROVAL OF DATA FINAL EXAMINATION OF RECORDS BASIN REVIEW Comparison Hydrographs Regional Analysis Comments STATION ANALYSIS PRESENTATION FOR APPROVAL FINALIZED DATA SUMMARY MANUALS AND BIBLIOGRAPHY MANUALS BIBLIOGRAPHY APPENDIX A: PROCEDURES FOR MANUAL COMPUTATION OF DATA...18 APPENDIX B: SYMBOLS AND FOOTNOTES...28 iii

192 1.0 PURPOSE AND BACKGROUND This lesson package, on the final stages of hydrometric data processing, is to be presented to technicians with about two years experience. The material is part of a comprehensive career development and training program for hydrometric survey staff. The participants will learn to complete the various forms that record the final computation procedures. The procedures used are performed without the aid of electronic data processing equipment and are not the ones currently used by the Water Survey of Canada. To truly understand the basic concepts of discharge computations, the data must be manipulated manually. Procedural errors could well arise if the technician were not aware of the functions the computer performs during automatic computations. Therefore, only the manual methods of computation are addressed, and only the manually completed forms are used in this lesson. Automated procedures, including the ones for computing final daily water level and daily discharges, will be presented in separate training sessions. A full discussion on estimating discharges in open water is included since this is not addressed elsewhere and is a critical part of data computations. 1

193 2.0 OBJECTIVES On completion of this lesson package, the technician should be able to : describe the procedures for computing and completing the final daily water level and daily discharge records for the year or standard period (on form or ) and for estimating missing periods to complete the records; explain procedures for computing monthly and annual summary data and the daily and instantaneous extremes of stage and discharge; explain procedures for the final examination of records, including comparison of hydrographs from other stations and basin analyses, to ensure continuity of records from one year to the next. 2

194 3.0 DAILY COMPUTATIONS Hydrometric records for each gauging station are computed and published annually. Prior to 1967, the reporting period varied from the calendar year to the water year (October to September). Since January 1968 the annual reporting period has been the calendar year. Data are collected at two distinct types of hydrometric stations : 1. water level only stations, where only the water levels are collected, and 2. streamflow stations, where both the water levels and discharges are collected. Water levels collected at water level only stations are published, as are discharge data collected at streamflow stations. In a few instances the water levels collected at streamflow stations are also published. The final daily water level and daily discharge computations follow the procedures described in chapter 5 of the Manual of Hydrometric Data Computation and Publication Procedures. For more detailed instructions, procedures, and comments on any particular step, refer to other appropriate training packages, particularly lesson packages 8, 18, 19, and 20. Figure 1 shows a flowchart for manual computation of streamflow data. Figure 1: Flowchart for manual computation of streamflow data 3

195 3.1 SIGNIFICANT FIGURES The following standards for significant figures in the completion of hydrometric data are from section 2.5 of the Manual of Hydrometric Data Computation and Publication Procedures. Water level : Water discharge : computations and publications : m cubic metres per second (m³/s) to three significant figures but not more than three decimal places. These rules will apply in completing form WATER LEVEL ONLY STATIONS Determination of daily mean gauge height is the subject of Lesson Package No. 8. For a detailed description of the distribution of gauge height corrections, as well as the procedure for computing corrected gauge heights, refer to pages 22 and in the Manual of Hydrometric Data Computation and Publication Procedures. The form in Figure 2 provides columns for daily mean gauge heights for the 12 months in the calendar year, as well as space for a summary for the year. Figure 2: Daily gauge heights form ( M) 4

196 3.3 STREAMFLOW STATIONS Daily Discharges Form ( ) The final daily discharges are computed by completing form , which is shown in Figure 3. This form provides columns for daily mean gauge height and discharge for 12 months, as well as spaces for monthly and annual summaries, which will be discussed in later sections. At the top of the form is space for general information such as the name of the station, drainage area, and type of recorder. The form must be prepared carefully because these final data are to be stored on file and used for publication. Figure 3: Computation of daily discharges (form ) Gauge Heights The corrected daily mean gauge heights computed from the original water level recorder chart or manual observations are copied into the columns headed Gauge Height. In addition, the maximum and minimum gauge heights that occurred during the year are listed in the spaces provided on the form. Symbols such as B for ice conditions, V for subdivided days, etc., are explained by a footnote on the bottom left margin. For days of recorder malfunction, if the daily mean gauge height is estimated, the symbol E is shown to the left of the gauge height value Shift Corrections As the next step before computing open water discharges, the values of shifts to be applied are entered in columns constructed on the left side of the wide columns headed Discharge on form The distribution of shifts was discussed in Lesson Package No. 19. For more on shifts, refer to page 30 in the Manual of Hydrometric Data Computation and Publication Procedures. 5

197 3.3.4 Discharges Open Water Open water discharges are determined by adding shift corrections to the gauge heights tabulated in the gauge height column of Figure 3 and by applying the appropriate stage discharge tables (Figures 4 and 5). Refer to pages in the Manual of Hydrometric Data Computation and Publication Procedures. Where more than one stage discharge table is used, a heavy horizontal line is drawn in the discharge column of form between the two dates separating the use of these tables, to warn the technician of the change. Figure 4: Stage discharge table (form ) Figure 5: Expanded stage discharge table (form M) Discharges Estimated under Ice Cover The details for estimating discharges under ice conditions are dealt with in Lesson Package No. 20. Also refer to pages in the Manual of Hydrometric Data Computation and Publication Procedures. The estimated discharges under ice will be found on the backwater computations form ( ). The daily discharges are then transferred to the daily discharge form ( ) Discharges Estimated in Open Water In general, the missing data should be estimated to produce a complete record in accordance with the operational intent of the gauging station. There must, of course, be reasonable confidence in the results. The subject of estimating periods of record is addressed briefly on pages in the Manual of Hydrometric Data Computation and Publication Procedures and an in-depth review of the subject is found in Methods for the Estimation of Hydrometric Data (1984). No provision has been made to deal with the subject of estimating discharges in open water in any of the lesson 6

198 packages. This subject is critical to the completion of the discharge records and will be addressed here in the form of a study of Methods for the Estimation of Hydrometric Data. As a reference in the continuing use of this lesson package a copy of the table of contents of Methods for the Estimation of Hydrometric Data is included as Figure 6. Because of the variety of methods of estimating records, these estimates are recorded on various worksheets. (The backwater computation form has been found to be an effective form for this purpose.) The daily values are then transferred to the daily discharges form ( ). Figure 6: Table of contents from Methods for the Estimation of Hydrometric Data 3.4 SUBDIVIDED DAYS At this point, all boxes for daily mean discharge in Figure 3 will have been filled except those opposite gauge height boxes that are blank for lack of record because of an instrument malfunction, or those opposite gauge height boxes that carry the symbol V for subdivided day. The discharges for subdivided days are computed next. The method of computation is explained in the section Subdivision of Daily Gauge Heights in Lesson Package No. 8, Gauge Height Computations. The daily mean discharges are computed on a gauge height chart or a worksheet and then transferred to the discharge column on form YEAR-END CONTINUITY There should be no discontinuity between the discharge on December 31 of the preceding year and January 1 of the current reporting year. That can easily occur if a new rating table is placed in effect on the first day of the current year, or if shift adjustments to the gauge height are used on either or both the first and last days of the two 7

199 calendar years. Consequently, the discharge for the last day of the preceding year should be examined to ensure consistency. 3.6 EXERCISE The following sample data are to be entered on form by the participants. The intent is to demonstrate methodology of data entry. Use the month of April. Day April GC GH C.M.G.H. (to be computed) Shift Q (to be computed) V V For this example use the following discharge table : GH Q Diff

200 Expand the table manually on form All units are metric. GC GH = gauge correction = gauge height C.M.G.H. = corrected mean gauge height Shift Q = shift see Appendix B = discharge - = no data GH must be estimated V A = See Appendix B (For this exercise C.M.G.H. is given) = See Appendix B. The recorder is assumed stopped, and manual observations were obtained from April 10 to 15 B = ice conditions see Appendix B. Assume ice conditions from April 5 to 12. 9

201 4.0 COMPLETION OF THE DAILY DISCHARGES FORM 4.1 MONTHLY AND ANNUAL SUMMARY In general, the mechanics of computing the total and average values are self evident. The computation procedures given here are from page 34 of the Manual of Hydrometric Data Computation and Publication Procedures Monthly and Annual Summary ( ) a. Do not round off the monthly or annual totals in (cubic metres per second) days this is the summation of the daily discharges. b. If daily discharges are not available for a complete month, do not compute the summary data for that month. c. If the records cover only part of the year and this period varies from year to year, compute the monthly summary data but do not compute any annual summary data. d. Compute the monthly summary figures as follows : i. mean divide the total of the daily discharges for the month by the number of days in the month. ii. cubic decametres (dam³) multiply the total of the daily discharges for each month by [Example : 1 dam³ = m³ 1 m³/s per day = 1 x 60 x 60 x 24 m³ = 86,400 m³ = (86,400 1,000) dam³ = 86.4 dam³] iii. iv. maximum (max) enter the maximum daily discharge for the month. minimum (min) enter the minimum daily discharge for the month. e. Compute the summary figures for the year or period as follows : i. mean divide the total of the daily discharges for the year or for the standard period by the total number of days, e.g., 245 days for March to October. ii. cubic decametres (dam³) add the rounded monthly figures and then round the total. Check this total by multiplying the total of the daily discharges for the year or period by Note, however, that the rounded summation figure is entered. 4.2 EXTREMES OF STAGE AND DISCHARGE The remaining entries on form (Figure 3) are maximum and minimum discharges. The guidelines for entering these values are presented on page 33 of the Manual of Hydrometric Data Computation and Publication Procedures as follows : 10

202 5.6.4 Maximum and Minimum Discharge a. Enter in the space provided on form the maximum instantaneous discharge for the year and the corresponding gauge height and the time of occurrence; delete the word daily. Note that the gauge height corresponding to the maximum instantaneous discharge may not be the same as the maximum instantaneous gauge height which occurred during the year. Note that the minimum instantaneous gauge height or discharge is not to be extracted unless required by the Region for a specific local purpose. [Maximum and minimum values, instantaneous and/or daily, are valid and may be entered only if there is a reasonable confidence that the value was not exceeded at any time during the calendar year, regardless of whether other periods were recorded]. b. Enter a note to indicate whether the maximum instantaneous discharge is based upon a high water mark, estimated from a graph, etc. If the maximum discharge is not reasonably well-defined by discharge measurements, the method of extrapolation should be given with an indication of reliability, e.g., by logarithmic extension or slope area measurement. Similarly, if the minimum daily discharge occurred during an ice period and is not reasonably well-defined by a discharge measurement, an explanation should be given, e.g., ice jam or regulated. c. If the maximum instantaneous discharge for the year is not available, either enter not known or not determined or delete the word instantaneous and enter the maximum daily discharge for the year. Also, enter the minimum daily discharge for the year. If it is desired to show a certain extreme discharge that occurred within a specific period during a year, enter an explanatory note on form stating the period for which it applies. d. If desirable, two maximum instantaneous discharges may be shown on form , for example, one during ice break-up and another during summer or autumn rain. e. [out of date, no longer valid]. f. When an extreme is the result of some unusual condition such as an ice jam, unusually heavy rain, stop log manipulation, etc., enter a suitable remark to that effect. 4.3 STAGE DISCHARGE TABLES Complete the section that refers to the stage discharge tables used, and their period of use. 4.4 ACCURACY STATEMENT The section on accuracy is no longer filled in on this form. The station analysis form explains the factors that affect the quality of data. 4.5 SYMBOLS AND NOTES An explanation should be given for each symbol used. Add any appropriate note that will enhance the records. Refer to pages in the Manual of Hydrometric Data Computation and Publication Procedures. 4.6 NOTES ON DATUM Notes on conversion to other datum must be included, e.g., To convert to G.S.C. datum (1967) add metres. 11

203 4.7 INITIALS The area of the daily discharge form reserved for the initials of the technicians who compute and check the record must be filled in as the work is completed. 4.8 APPROVAL OF DATA The approval process is the jurisdiction of the Regional Office. The data computations must be approved by the designated persons, usually supervisors, area heads, and area engineers. The person approving the data for publication must sign in the appropriate location on the right-hand margin of the form. 12

204 5.0 FINAL EXAMINATION OF RECORDS Completion of the discharge form ( ) marks the end of the actual computation of discharge for each calendar year. 5.1 BASIN REVIEW As well as reviewing the records for each individual station in the final examination, a comparison of records for stations within a basin, or in an adjacent basin, could reveal major errors or confirm the records. Two methods for comparing data are : 1. comparison hydrographs, and 2. regional analysis. In the event anomalies are discovered, a complete review of the records involved should be undertaken Comparison Hydrographs The comparison hydrographs for current data may be obtained by overlaying hydrograph plots and examining them on a light table. It may be useful to record which stations give good comparison and which do not and why not. The comparison hydrographs (see Figure 7) should reveal any large discrepancies caused by false interpretation of data, as might be caused by weeds, ice, plugged intake pipes, etc. They may also reveal certain computation errors, such as the use of the wrong stage discharge curve. The hydrographs may also be useful for estimating missing periods or for validating extremes codes. Questionable periods should be examined and if necessary revised. Several daily discharge hydrographs may be plotted in contrasting colours on the same sheet with or without individual discharge scales. Hydrographs for stations on the same stream will usually bear a close resemblance to each other (see Figure 7), and those for stations on other streams in the same general region will usually show at least a general resemblance Regional Analysis The evidence obtained by comparative study of hydrographs is important in verifying the consistency of the respective daily discharge records. Although hydrographs generally indicate similarity of form, they provide less reliable information with respect to relative magnitudes. Because of this fact, it is customary whenever there are several stations in various parts of a drainage basin to make a critical study of at least the monthly and yearly figures on the basis of both the total and the unit discharge from intervening areas. Figure 7: Comparison hydrographs (form ) 13

205 For instance, when there are two stations on a stream, monthly mean discharge values for the intervening area may be obtained by subtraction, and from those values unit discharge figures in cubic metres per second per square kilometre are determined. If these figures of unit discharge for the intervening area are consistent with the corresponding figures for the upper and lower stations, a good check on the accuracy of both records is afforded. Making such analyses in large river systems may be complex and involved; due allowance must be made for time lags, uneven precipitation patterns, and the possible effects of storage and diversions if either occurs within the basin. However, it should be recognized that in this process (regional analysis) the error in the figures for the upper and lower stations are carried to the smaller figures of the difference. If such errors are of the same sign and if the difference is not relatively small, the percentage error in the difference will not be great; but if such errors are of the opposite sign, even though small when applied to the figures to which they properly pertain, they may be large when applied to the smaller figures of difference Comments As it is important to ensure continuity of records one year to the next, discharge data for the end of the previous year should be examined to ensure consistency with current year data. Any necessary corrections should be made immediately, if possible. In the event that significant changes would be required for beyond the reporting year (e.g., change of stage discharge curve) a full-scale review of the station should be initiated. The criteria for the review of streamflow data are outlined in the Manual of Hydrometric Data Review Procedures. A detailed description of the hydrometric data review procedures is presented in Lesson Package No. 23, Historical Data Review. 5.2 STATION ANALYSIS The next step in the computation procedures is the recording of a complete analysis of data collected, procedures used in processing the data, and the logic upon which the computations were based for each year of record. This provides a basis for review and serves as a reference in the event that questions arise about the records at some future date. Such a report is called the station analysis (form , shown as Figure 8). This subject and form will be addressed in Lesson Package No. 22, Station Analysis. 5.3 PRESENTATION FOR APPROVAL Prior to presentation for final approval, the technician should ensure that all pertinent forms are completed. The package to be presented for final approval should include : Figure 8: Station analysis form ( ) 1. station description 2. recorder charts and/or water level observations 14

206 3. field notes 4. stage discharge curves and tables 5. daily gauge height (water level only) 6. daily discharges 7. hydrographs 8. gauge history 9. gauge corrections 10. discharge measurement 11. shift corrections 12. backwater computations 13. worksheets 14. station analysis plus any other pertinent information. 5.4 FINALIZED DATA The finalized data are submitted to Ottawa annually. Printouts are returned to the Regions for verification to ensure that the correct data are stored on file for publication and also for distribution to users. 15

207 6.0 SUMMARY Basic daily discharges are computed by Regional personnel and submitted to Ottawa for publication annually by May 1 st. Some of the final steps in the annual computation procedures include : A. completion of the daily discharges form B. final examination of records C. completion of the station analysis form. Although many parts of hydrometric data computation procedures have been automated, certain operations are and will continue to be performed manually. The final examination of records is one operation that has to be performed manually. Manual performance of all the above procedures is covered in this lesson package. On completion of this training, the participant should have a clear understanding of : 1. what is required to successfully complete the station file for submission to the supervisor, and 2. what happens during the final annual data computation and examination. 16

208 7.0 MANUALS AND BIBLIOGRAPHY 7.1 MANUALS Environment Canada (1980a), Manual of Hydrometric Data Computation and Publication Procedures, 5 th ed., Inland Waters Directorate, Water Resources Branch, Ottawa. (1980b), Manual of Hydrometric Data Review Procedures, 5 th ed., Inland Waters Directorate, Water Resources Branch, Ottawa. (1984), Methods for the Estimation of Hydrometric Data, Inland Waters Directorate, Water Resources Branch, Ottawa. 7.2 BIBLIOGRAPHY Rantz, S.E., et al. (1982), Measurement and Computation of Streamflow : Vol. 2, Computation of Discharge, U.S. Geol. Survey Water Supply Paper

209 APPENDIX A: PROCEDURES FOR MANUAL COMPUTATION OF DATA (from Manual of Hydrometric Data Computation and Publication Procedures, pp ) 5. PROCEDURES FOR MANUAL COMPUTATION OF DATA This section contains detailed procedures for the manual computation of streamflow and water level data. General instructions are given in section 2 and detailed automated procedures are given in one of the manuals listed in section GAUGE HISTORY ( ) a. Describe the type and location of existing bench marks and, if readily available, give the date of installation. Enter the elevation of each bench mark and state whether it is referred to an assumed or a standard datum. For Geodetic Survey of Canada bench marks, give the BM No. and the Publication No. (and year of edition) from which the elevation was obtained. b. Enter the elevation of the gauge datum. c. When a change in the elevation of a bench mark or the gauge datum is made, explain the reason for the change on the bottom of the form and start a new form with the appropriate entries. d. Enter the results of all the level checks that were made on all the gauges at the gauging station for the period of record being computed; indicate in the Notes column if a gauge has been re-set, extended, destroyed, damaged, etc. e. Describe any changes in the location of gauges; also explain any major changes in equipment at a gauging station. f. The same sheet may be used from year to year if there is sufficient space to explain clearly what has occurred. 5.2 GAUGE CORRECTIONS ( ) a. Enter on form , the gauge corrections as shown on Gauge History form for the year for which records are being computed. Circle these corrections. Enter the last correction prior to the beginning of the year and the first correction after the end of the year; this may not be applicable in some cases for records collected on a part-year basis where the first gauge correction after the end of the year is not available until the following spring. b. If the date on which the change occurred is not known, assume that the change occurred uniformly and distribute the correction in accordance with one of the two following methods : i. Divide the change in the correction by the number of days to find the change per day. For example : suppose the correction was found to be on March 20 and on March 30. The number of days involved is 10 and the change in correction is The corrections to be applied are shown to the nearest thousandth of a metre. ii. When the change is small and the number of days is large, the preferable method is to divide the number of days by the change in correction. For example : suppose the correction is on May 25 and on October 15. Dividing the period of 144 days by 3 gives 3 intervals of 48 18

210 days each. No change in correction will be applied during the first one-half interval of 24 days, i.e. the correction will be continued from May 25 to June 17; an increase of in the correction will be applied during each of the next two intervals of 48 days, i.e. a correction of from June 18 to August 4 and from August 5 to September 21. The remaining change will be applied during the remaining one-half interval, i.e. the final correction of will be applied from September 22 to October 15. c. The gauge correction sheet should be prepared up to the date of the first level check in the following year. 5.3 DISCHARGE MEASUREMENTS ( ) a. Enter the date of the discharge measurement. If a non-conventional technique (such as moving boat, fluorometric, etc.) was used in measuring the discharge, indicate the method of measurement in the Remarks column. b. Enter the name of the person who made the measurement. If the measurement was made by the USGS, PFRA, or any other co-operating organization, only the name of the organization need be indicated. c. Enter the air and water temperatures as obtained at the time of the measurement. d. Enter the width, area, mean velocity and discharge, using significant figures as shown in section 2.5. If ice is present in the stream or if the discharge is estimated, insert the appropriate reference or symbol in the Remarks column. e. Extract the weighted mean gauge observation corresponding to the measured discharge from the front sheet of the discharge measurement notes (form ). Apply the appropriate gauge correction from form to this observation and enter the result in the Mean Gauge Height column. If the gauge height corresponding to no flow is determined, enter it in the Remarks column. If there are unusual conditions affecting the stage-discharge relation such as inflow between the gauge and the measuring section, note this in the Remarks column. f. If discharge measurements at a station are made at more than one location, a symbol should be entered under Remarks to distinguish them in the event that it is necessary to use the cross-sectional area or the mean velocity. g. If any other information pertinent to the discharge measurement is obtained, note this in the Remarks column. 5.4 GAUGE HEIGHT COMPUTATIONS Compute the mean gauge height for each day by applying appropriate corrections to the original gauge record and enter on form or For a manual gauge, a single observation per day or the mean of two or more observations per day is usually used to represent the mean gauge height for a day. Where gauge heights are shown and the relation between the gauge datum and a G.S.C. or other standard datum is known, indicate the adjustment necessary to convert the gauge heights to elevations, e.g. Add m to convert gauge height to elevation above mean sea level (Geodetic Survey of Canada datum, Publication 24, 1951 Edition) Manual Gauge a. Transfer to the observer's book any pertinent observed water level data which have not already been entered and indicate the source. If there is a definite reason why some observations should not be used in determining the daily mean gauge heights, explain this in the observer's book and on the Station Analysis form

211 b. Determine the daily mean gauge observations to be used and apply the appropriate gauge corrections to the mean observations. Enter the resulting daily mean gauge heights on form or When the stage is rapidly rising or falling, greater accuracy in determining the daily mean stages may be achieved by plotting the gauge heights on a graph. When more than two observations are made during any one day and a graph is not drawn, consideration should be given to weighting them rather than taking the mean. c. If the mean is obtained from more than one observation, enter this mean in the observer's book. If the mean is obtained from a graph, enter the mean and an explanatory note. d. Where applicable, follow the rules for subdivision as outlined in section 5.4.2(k). e. Enter the maximum instantaneous water level for the year in the space provided on form , or , stating the date and how it was obtained, e.g. from high water mark, estimated from graph or observation at peak ; delete the work daily. When an extreme is the result of some unusual condition such as an ice jam, unusually heavy rain, stop log manipulation, etc., enter a suitable remark to that effect. If the maximum instantaneous gauge height for the year is not known, then either enter Not known or delete the word Instantaneous and enter the maximum and minimum daily mean gauge heights for the year. f. Do not enter extremes of stage for canals. g. Use symbols if necessary (see section 2.7) Recording Gauge a. Good field practice requires that the following information be noted on recorder charts at the time they are removed from the recorder : i. name of gauging station, ii. iii. scales of chart, and time and date on which the chart was started and removed and the gauge observations made on those dates; also a record of any re-setting between the terminal dates. These data should be entered on the chart if the field officer has omitted them. b. Inspect the time as recorded at the beginning and end of the chart, and on any intermediate days, to determine the total time correction that should be applied. After inspecting the chart carefully to see that any difference between the chart time and the actual time is not due to re-setting, stoppage, etc., indicate the total time correction at the end of the chart, e.g. T 3 hrs fast or T 1 hr slow-used OK, etc. The error in time may usually be neglected if the total error in a period of about one month is less than two divisions on the time scale. Distribute the total time correction according to one of the methods described in section 5.2 for distribution of gauge corrections. Apply time correction distributions only to the nearest division. For example, if a chart on a scale of 60 mm=1 day was OK on June 1 and three hours fast on June 13, then three of those days (June 3, June 7 and June 11) would be increased by 1 hour (1 division) - these three days would have 25 hours and all the others 24. Indicate the corrected midnight by a vertical line broken at the graph line. Enter the dates in the margin at the top or bottom of the chart at the respective noon lines. c. The recorder pen is usually set to read the same as the inside gauge (IG). If the IG is not used, indicate the reference gauge that was used at the beginning of the chart and on the Station Analysis form

212 Inspect the observations given for the manual gauge and for the pen at the beginning, intermediate points, and end of the chart and determine the pen correction to be applied. Indicate the total pen correction at the end of the chart and at any place of re-setting. Distribute the total pen correction according to one of the methods described in section 3.2 for distribution of gauge corrections. d. Examine the chart to see if a reversal has occurred. If one has occurred, identify the point of reversal by the abbreviation Rev. and indicate the amount of correction to be applied due to the point of reversal not coinciding with the top or bottom of the chart. e. When the chart line is missing for part of a day, it may be estimated and marked on the chart by a dashed line for use in determining the daily mean observation. If the chart line is missing for one or more days, the daily mean observation may be based upon the available manual gauge observations. In either case, the resulting daily mean values should be identified by the symbol A. f. When adding notes or corrections to the chart or interpolating for missing records, care must be taken to preserve the original record. Do not trace over the original pen or pencil record. g. Compute the daily mean observations by one of the following methods : i. Balance the areas on either side of the mean value by the use of a straight-edge or scanner. A scanner is a clear rectangular plastic device approximately 3 cm x 15 cm x 2 mm with a longitudinal hair line on the back bisecting a hole drilled at the mid-point to receive a pencil point. ii. Divide the day into two or four equal parts, determine the mean for each part and then mean these values to obtain the mean for the day. For example, suppose the day is divided into four parts of six hours each. The mean observation for the first period of six hours is indicated by a dot at the mid-line (the 03:00 line in this case). The mean for the second six-hour period is indicated by a dot at the mid-line (which is the 09:00 line). A line is drawn from the dot on the 03:00 line to the dot on the 09:00 line, and the point at which this line crosses the 06:00 line is the mean observation for the first 12 hours of the day. Do the same for the last 12 hours of the day and connect the two 12-hour means by a straight line. The point at which this line crosses the noon line is the mean observation for the day. h. Compute the daily mean observations by applying the appropriate pen corrections and reversal corrections (where applicable). In arriving at the daily mean observations, the individual corrections applied to each daily mean observed value should be shown separately rather than as a net correction. i. Compute the daily mean gauge heights by applying to the daily mean observations, the appropriate gauge corrections for the inside gauge or other manual gauge to which the chart record is referred. Enter the gauge heights on form or This procedure may be delayed until the end of the year when the gauge corrections applicable to that year have been determined. Application of the gauge correction may or may not be shown on the recorder chart. If gauge corrections are applied on the chart, use the abbreviation GC after each gauge correction figure. j. The daily mean gauge height normally is used to compute the daily mean discharge. However, a daily mean discharge determined directly from the daily mean gauge height may be in error for a number of reasons, including the following : i. The rate of change in stage. ii. The relative condition of the river (high or low). 21

213 iii. iv. The shape of the stage hydrograph for the day and the proportion of time during which the stage is relatively high or low. The relative curvature in the stage-discharge curve in the range of stage recorded during the day. k. To obtain a more accurate determination of the daily discharge, it may be necessary to subdivide the day into two or more parts, determine the mean gauge height for each part, determine the discharge for each mean gauge height and from these compute the weighted mean discharge for the day. If the resultant weighted mean discharge differs from that determined using the mean gauge height by more than a selected allowable limit, say 2% for discharges above 0.3 m3/s, or m3/s below 0.3 m3/s, then subdivision is necessary for all similar conditions. A suggested method of determining the necessity for subdivision is to use an allowable range table which may be prepared by trial and error as follows : i. From the stage-discharge table select a range in stage during medium flow from, say, 3.0 to 4.0 m Discharge at gauge height 3.0 m equals 186 m3/s Discharge at gauge height 4.0 m equals 339 m3/s Mean discharge equals 262 m3/s. However, at a mean gauge height of 3.5 m, the discharge is 252 m3/s. This is a difference of 4% (10 divided by 262, x 100), which is not allowable. ii. Select a smaller range, say from 3.0 to 3.4 m, which gives a difference of 1% which is too low, but 3.0 to 3.6 gives 2%. iii. Now try between 4.0 and 4.6. This is 1%, which is too low so try between 4.0 and 5.0 which is 3%. Therefore, an allowable range of 0.8 m is about right. iv. The range from 6.5 to 7.5 will give 2%. v. After several such attempts an approximate allowable range table will evolve. vi. When in doubt, subdivide! l. Mark the maximum instantaneous gauge observation for the year on the chart. m. If the period of usable record and the period covered by the chart are not the same, the period of usable record should be indicated at the beginning of the chart with a note explaining why the remainder of the chart record is not to be used. Do not destroy a chart even if all of it is considered unreliable as the presence of it on files will show that a useful record was not obtained from a recording gauge for that particular period. 22

214 5.5 STAGE-DISCHARGE RELATIONSHIP Stage-Discharge Curves a. Select scales on the curve sheet (form or ) so that the significant figures as required for the stage-discharge table can be read with reasonable accuracy. Gauge heights are plotted on the vertical scale and the discharges on the horizontal scale. Suggested scales for the gauge height are 1 cm=2, 1, 0.5, 0.2 or 0.1 m and for the discharge, 1 cm=20 000, , 5000, 2000, 1000, 500, 200, 100, 50, 20, 10, 5, 2 or 1 m3/s. Make adequate provision for the entire range in stage which is known to have occurred during the history of the records. The stage-discharge relationship may have to be shown in one or more curves to obtain the degree of accuracy required for the computation of the stage-discharge table. Mark each curve low water curve, high water curve, etc.; where feasible, carry each curve down to or near the zero flow stage. Allow for at least 0.3 m of overlap between curves and use more than one sheet if necessary to avoid cramping and confusion. b. When a new curve sheet becomes desirable, first plot all extreme high or low discharge measurements from former years on the new sheet. On the new sheet, plot the latest available stage-discharge curve. Finally, plot all the open water measurements for the current year and, if necessary, plot a new stagedischarge curve for the current year. c. Indicate the plotted point for each discharge measurement by a dot, surrounded by an open circle about 2mm in diameter. Circles that indicate measurements for previous years may be filled in with ink which will distinguish them from the measurements made during the current year. Designate a discharge measurement by its date (e.g. June 12, 1967) with a diagonal line from the plotted point (use the same angle, say 60o, on each sheet or draw the diagonal line about perpendicular to the curve). Measurements known to be affected by backwater may be plotted in pencil or by use of a distinctive symbol. If it is desired to identify measurements made by another organization, use a different symbol (e.g. a triangle, square or cross), with an explanatory note in the lower right-hand corner of the curve sheet. d. In many cases, it is necessary to plot the measurements on log paper (form ) to determine the shape of the curve, particularly at high water stages. The gauge height corresponding to the point of zero flow is determined approximately, to the nearest decimetre or to the nearest metre depending on the size of the stream, and is entered in the space provided on form The discharges are plotted against the difference between the mean gauge height for the discharge measurement and the gauge height at zero flow. In most cases, this log plot of measurements will form a straight line in the high water range making it a useful tool in extending curves beyond the highest discharge measurement. The curve as determined in the log plot is then transferred to form or e. Another method of determining the shape of, or extending, the stage-discharge curve is to plot the crosssectional areas and mean velocities against gauge height. From these two curves, the area and mean velocity corresponding to a selected high stage are used to determine a computed discharge which is then plotted on the stage-discharge curve sheet. f. If a log plot or an area-velocity study is used to determine the shape of any part of a stage-discharge curve, insert an explanatory note under Remarks in the title block on the basic stage-discharge curve sheet (form ). g. The following procedure will be used in labelling stage-discharge curves : i. The first curve used in the first year of operation will usually be designated Curve No. 1. However, another number, such as 31, may be selected if desired but do not start with No. 1 if this method of labelling curves was in use in previous years. 23

215 ii. iii. iv. Use a diagonal line from the curve to the notation. Label any succeeding curves as Curve No. 2, Curve No. 3, etc. (or Curve No. 32, Curve No. 33, etc.) Enter the dates for the period of use of each curve in the space provided. h. Complete all the information on the curve sheets in ink Stage Discharge Tables a. Enter the number of the stage-discharge table, which must correspond with the stage-discharge curve number, in the space provided on form or Note that the initials of the computer and checker and the date the table was computed are also to be entered. b. When computing the stage-discharge table, deviate as little as possible from the figures as indicated by the curve. Express discharges to at least the same number of significant figures as required for daily discharges. c. In computing the table it may be necessary or desirable to show a discharge figure for each m of gauge height as provided for in form This table is convenient where the flow during most of the year is confined to a relatively small range in stage. d. In computing the stage-discharge table certain refinements may have been made in the computations to adjust for the fact that the curve may not have been a smooth curve. When the stage-discharge table is completed, plot the values on the curve sheet to ensure that the original delineation of the curve is consistent with the table. e. In some cases, a new stage-discharge curve is exactly the same as a former curve through part of the range in stage. In preparing the new stage-discharge table for these areas, copy the data from the former table through the range of stage in which the new curve and the former curve are identical, then compute the new table in the range of stage where the two curves diverge. The new table will cover the entire range of stage. f. If a stage-discharge curve is extended above or below the original range, the same original no. and date identification may be used. However, an explanatory note should be added on form as well as the date when this extension was made. Note that this applies only if the curve is extended and not if it is revised. g. Enter the dates for the periods of use of each table in the space provided. 5.6 DISCHARGE COMPUTATIONS Shift and Backwater Corrections a. For many stations, a shift in the station control or a backwater condition may occur at certain times during the year as a result of weed effect, beaver action or ice conditions. During such periods, shift or backwater corrections are determined from available discharge measurements; these corrections are entered on form and used subsequently to compute daily corrections, which are applied in the determination of the daily discharges. b. However, apart from these measurements, which plot off the curve for reasons indicated above, the majority of the measurements will plot somewhat off the curve as a result of normal scatter. For these, no 24

216 correction is computed; however, it is normally found useful for purposes of expressing mathematically the degree of scatter, to indicate for each measurement the percentage difference between measured discharge and the discharge indicated by the stage-discharge relation. These percentage differences are entered in the Diff. column on form If desired, these differences may be expressed in cubic metres per second instead of percentage for discharges less than about 0.5 m3/s. c. Following is an example of the computation of shift and backwater corrections, and the difference between measured discharge and the indicated discharge from the stage-discharge table : i. From a discharge measurement (form ), the mean gauge height is m and the discharge is m3/s. From the stage-discharge table, the discharge of m3/s corresponds to a gauge height of m, indicating that a shift correction of m would have to be applied to the mean gauge height for the day to produce results consistent with the discharge measurement. ii. From a discharge measurement (form ), the mean gauge height is m and the discharge is 708 m3/s. From the stage-discharge table, the gauge height of m corresponds to a discharge of 696 m3/s. The difference between the measured discharge and that indicated by the stage-discharge table is ( ) divided by 696 x 100=1.7%. d. A discharge measurement made during the computation period may plot substantially off the stagedischarge curve. If after careful analysis and review, no satisfactory cause of its departure from the stagedischarge curve can be determined, the measurement should be eliminated from use in the computation. In this instance do not enter any figure in the Shift or Diff. columns, but enter an explanatory note in the Remarks column on form , as well as Station Analysis form Open Water a. In the space provided on form , enter the number and date of each stage-discharge table that is to be used and indicate the specific period for which each table applies. b. If no shift or backwater corrections are applicable, use the stage-discharge table and the gauge heights directly to obtain the daily discharges. c. If shift or backwater corrections are to be applied, rule in an extra column to the right of the gauge height column. Enter for the appropriate dates the correction established by the respective discharge measurements. Circle these corrections. The distribution of the shift or backwater corrections from day to day will depend upon the interpretation of the cause of the shift; enter a brief explanation of the interpretation used on the Station Analysis form Distribution may be made on a straight-line basis in accordance with one of the methods described in section 5.2. Instead of using an extra column on form for entering shift or backwater corrections, it may be more desirable in some cases to apply these corrections by the use of form d. Enter on form the daily discharge as computed on the subdivided-day work sheet. 25

217 5.6.3 Ice Conditions a. Because of the many variable factors involved, no single standard procedure is suggested for the computation of daily discharges during periods when the stage-discharge relation is affected by the presence of ice. Several methods of computing discharges under ice conditions are available and it is suggested that the Regional Offices use the method that best suits each individual station. b. One method of computing discharges under ice conditions is as follows : i. For each ice-affected discharge measurement, enter on form the gauge height and discharge (from form ) and the effective gauge height and the backwater as computed from the stage-discharge table. To ensure continuity in the backwater interpretation, enter these data also for the last measurement before the beginning of the ice period and for the first measurement after the end of the ice conditions. ii. iii. iv. Transfer any pertinent remarks from the observer's record, measurement notes, weather records, etc., to the Remarks column of form These remarks should be of assistance in providing a basis for backwater interpretations. Transfer the daily gauge heights from form to the Daily Gauge Height column in form Arrange the scales on a Winter Hydrograph form or equivalent, to allow for plotting of the following : 1. maximum and minimum (or mean) temperatures, 2. backwater, 3. gauge heights (both daily and effective), and 4. discharge. v. Plot the following on form : 1. daily maximum and minimum (or mean) temperatures obtained from the appropriate meteorological station, 2. the gauge height and discharge from each discharge measurement and the effective gauge height and backwater correction as computed from the stage-discharge table (from form ); circle these plotted points, and 3. the daily gauge heights. vi. Draw the backwater graph on form The method of drawing this backwater graph will probably vary with each gauging station and will be dependent upon such factors as : 1. formation, storage and release of slush, 2. rate of ice formation, 3. temperature, 4. precipitation, 26

218 5. ice-jamming, 6. amount of snow cover, etc. vii. Transfer the daily backwater corrections from form to form and compute the effective gauge heights; compute the discharges corresponding to these effective gauge heights. viii. Plot the effective gauge heights and the corresponding discharges on form ix. The discharge hydrograph for an adjacent station may be plotted for comparison purposes. Certain previous interpretations may be changed to make the discharges appear more consistent. However, in trying to make these records appear more consistent, do not overlook the possibility that there may be some valid reason for the apparent inconsistency. x. Transfer the daily discharges from form to form c. Where discharge measurements are made frequently during the ice period, it may be considered unnecessary to plot a winter hydrograph. The computation of the daily discharges then may be made directly on form but in a manner similar to that outlined in section (b) above. d. When a daily gauge height record is not obtained during the ice period, another method of computing discharges under ice conditions is as follows : i. Enter on form the measured discharges obtained during the ice period and any pertinent information which may be of value when drawing the daily discharge graph. ii. Plot the following on Winter Hydrograph form : 1. the daily maximum and minimum (or mean) temperatures obtained from the appropriate meteorological station, 2. the measured discharges ( circle these plotted points), and 3. the discharge hydrograph for an adjacent stream, if available and if desirable. iii. Draw a daily discharge graph using a hydrograph for an adjacent stream, the temperature plot and other pertinent information as a guide. iv. Transfer the daily discharges from form to form v. Transfer the daily discharges from form to form vi. If desirable, the use of form may be eliminated in this method and the daily discharges transferred directly from the winter hydrograph to form

219 APPENDIX B: SYMBOLS AND FOOTNOTES a. A Manual Gauge Use this symbol during open-water periods to identify the use of one or more manual gauge observations to obtain a daily stage at a station where the water-stage recorder was temporarily out of operation. Enter this symbol to the right of the daily discharge figure or to the right of the daily stage figure if no discharge data are shown. This symbol will also be used when the chart record for only part of a day is available. During a year when a recorder is installed the symbol A will be used on all days prior to the chart records to identify manual gauge readings. Do not enter this symbol in any monthly or annual summary data, except for the extremes in the annual summary, if applicable. Do not use this symbol during ice periods. However, a footnote will be required if the recording gauge was not in operation in winter periods. Use of this symbol must be accompanied by an appropriate reference in a footnote (i.e., A manual gauge). The symbols B or E have precedence over the symbol A. b. B Ice Conditions Use this symbol to indicate that ice conditions in the stream have altered the open water stage-discharge relationship. The symbol is entered to the right of the daily discharge figure. This symbol will not be used for water level data. However, if it is required for specific stations, an appropriate explanation should be given in the station analysis form Do not enter this symbol in any monthly or annual summary data except for the extremes in the annual summary, if applicable. Use of this symbol must be accompanied by an appropriate reference in a footnote (i.e., B ice conditions). The symbol B has precedence over the symbols A and E. c. D Dry Use this symbol to indicate that the stream or lake is dry or that there is no water at the gauge. This symbol is used as an updating correction in the MANUAL program or as input to the LEVELS file, and the word DRY will appear in the gauge height column without a footnote. d. E Estimated Use this symbol whenever the discharge during open-water periods was determined by some indirect method such as interpolation, significant high-water extension, comparison with other streams, or by correlation with meteorological data. If desired, the method of estimate may be given in a suitable footnote. Enter this symbol to the right of the daily discharge or daily water level figure. Do not use this symbol during ice periods. Do not enter this symbol in any monthly or annual summary data except for the extremes in the annual summary, if applicable. Use of this symbol must be accompanied by an appropriate reference in a footnote (i.e., E estimated). The symbol E has precedence over the symbol A. e. Where one of the symbols A, B or E is applicable, show either a symbol for each day or only a reference in a footnote. Show a symbol for each day if the symbol applies to more than two periods; otherwise, show only a reference in a footnote. However, the output listing from the FLOW or LEVELS files or the digitizer applications and related programs will show a symbol for each day, where applicable, regardless of the duration. 28

220 Examples of footnotes without symbols are as follows : Manual gauge, May 20 to July 20 and August 21 to 23. Ice conditions, January 1st to April 10 and October 27 to December 31. Estimated, June 1st to 29. f. V Subdivided Use this symbol when the daily gauge height record is subdivided into two or more periods to compute the daily discharge. Enter this symbol in the gauge height column and omit the daily mean gauge height for that day. However, if a daily water level is required to compute monthly mean water levels, it is to be computed from the continuous water level record and not from the daily discharge (the symbol V in this case would be shown to the right of the daily water level). Use of this symbol must be accompanied by an appropriate reference in a footnote (i.e., V subdivided). However, note that this symbol will not appear in any publications. g. Enter the following footnote on the station analysis form , with the appropriate dates, when any part of a streamflow or water level record has been prepared by computer methods : Data to processed by digitizer and computer methods. h. In summary, although only the symbols A, B, D, E or V will be used, only the symbols A, B or E will be accompanied by a footnote in the data publications or on printouts. Explanatory footnotes may be used if the symbol applies to one or two periods, or to explain that the recording gauge was not in operation during all or part of winter periods or that a gauge height graph was used for a certain period. Examples of footnotes are as follows : Recording gauge not in operation during ice periods. Recording gauge not in operation, January 1 st to March 5 and November 15 to December 31. Recording gauge not in operation continuously during the ice periods. Gauge heights from graph of observed readings, May 20 to June 10. i. The computer printouts for daily discharges and water levels will show a symbol for each day, where applicable. 29

221 THE WATER SURVEY OF CANADA HYDROMETRIC TECHNICIAN CAREER DEVELOPMENT PROGRAM Lesson Package No. 22 Station Analysis Form J.F. Beaty Water Survey of Canada Environment Canada 100 Park Street Kenora, Ontario Canada P9N 1Y6

222 Copyright All rights reserved. Aussi disponible en français

223 TABLE OF CONTENTS 1.0 PURPOSE AND BACKGROUND OBJECTIVES STAGE RECORD DISCHARGE MEASUREMENTS STAGE-DISCHARGE RELATIONSHIP REMARKS SUMMARY MANUALS AND REFERENCES FIELD MANUALS OFFICE MANUALS REFERENCES... 9 APPENDIX 1: FLOW CHART FOR THE COMPUTATION OF STREAMFLOW DATA...10 APPENDIX 2: STATION DESCRIPTION FOR THE EXAMPLE STATION...12 APPENDIX 3: GAUGING STATION INVENTORY FOR THE EXAMPLE STATION...13 APPENDIX 4: GAUGING STATION INVENTORY UPDATING FORM (SAMPLE)...14 APPENDIX 5: GAUGE HISTORY FORM FOR THE EXAMPLE STATION...15 APPENDIX 6: DISCHARGE MEASUREMENT FORM FOR THE EXAMPLE STATION...16 APPENDIX 7: STAGE DISCHARGE TABLE FORM FOR THE EXAMPLE STATION...17 APPENDIX 8: STAGE DISCHARGE CURVE FOR THE EXAMPLE STATION...18 APPENDIX 9: STAGE HYDROGRAPH FOR THE EXAMPLE STATION...19 APPENDIX 10: DISCHARGE HYDROGRAPH FOR THE EXAMPLE STATION...20 APPENDIX 11: STREAMFLOW ANNUAL PAGE FOR THE EXAMPLE STATION...21 APPENDIX 12: BLANK STATION ANALYSIS FORM APPENDIX 13: STATION ANALYSIS FORM FOR THE EXAMPLE STATION...23 iii

224 1.0 PURPOSE AND BACKGROUND The final step in the computation process is the careful preparation of a Station Analysis form ( ). A properly prepared Station Analysis form is a detailed summary of the interpretation and procedures used during the year to compute hydrometric records for a particular hydrometric gauging station. The technician completes the form in either point form or narrative style. It should contain enough information to allow anyone unfamiliar with the gauging station to understand the interpretation of the hydrometric record for that station. A Station Analysis form must be prepared for : miscellaneous discharge measurements; stream, lake or reservoir stage; lake or reservoir stage and contents; stream stage and discharge (streamflow). The only exception is when miscellaneous discharge measurements are not taken at a hydrometric gauging station. The Station Analysis Form is usually approved by either a Hydrometric Supervisor or an Area Engineer. It is retained for reference and review in the station work file. For continuity, the technician reviews the previous year's station analysis as an integral part of an ongoing annual review before beginning computations for the current year. The review ensures that trends and anomalies peculiar to a specific gauging station will become more readily apparent. Many districts have recently incorporated computerized versions of the Standard Stations Analysis form. Notwithstanding local variances, the documentation procedures and requirements are universal. The technician completes the Station Analysis to ensure that all data submitted for final publication have been thoroughly checked and computed in accordance with National Standards. 1

225 2.0 OBJECTIVES The objective of this Lesson Package is to learn the steps involved in completing Station Analysis form ( ) for hydrometric data computations. This will include a brief description of the hydrometric station including the gauge, bench marks and related structures as well as a description of any changes that occurred during the year. Other items that must be recorded on the Station Analysis form include : number and date of level checks and distribution of gauge corrections; gauges used, and reason for any missing stage record; number of discharge measurements obtained, when, and if the range of stage was covered; period of use of stage discharge tables, including an explanation of any shift corrections; automated procedures, special computations, especially for deriving flow estimates; method of winter computations, including meteorological records used; and basin analysis, hydrograph comparison and degree of regulation. 2

226 3.0 STAGE RECORD Before you begin computations, you must assemble data sheets, notes and forms from a station work file(s). For example, see Appendices A-2 to A-11, which contain data sheets, notes and forms for an example station on the Turtle River near Mine Center. A-12 is a blank Station Analysis form to be filled in. The instructor will discuss and review each section, Stage Record, Discharge Measurements, Stage Discharge Relationship and Remarks. After each section has been presented, the technicians fill in the blank form and compare results with a sample form provided by the instructor. Use the following procedure when you complete the stage record section of the Station Analysis form. Examples are provided for clarity. Describe the types of recording, non-recording and auxilliary gauges located at the station and used during the computation year. These should be consistent with HYDEX (Gauging Station Inventory) and Station Description sheets. Where more than one gauge was used during the year to compute hydrometric record, state the period of use of each. Specify whether records are in ink, pencil or digital format. Identify the manual gauge(s) that stage record is referenced to. Example : Gauging station consists of a float-actuated A-35 recorder with negator spring drive and a battery-powered, float-actuated Telemark. Records are in ink, and pen is set to a 15.0 inside staff gauge. Telemark is set to 'corrected' gauge height. Briefly describe the removal, relocation or upgrading of gauges/recorders at the station. Give dates where applicable. It is not necessary to explain routine maintenance such as replacing of gauge plates or painting. Example : Former weight-driven A-35 recorder removed on March 12 th. 5.0 m outside staff gauge removed by ice on April 1 st. State the operational period (Seasonal, Continuous, or Specific period) indicating months of operation and minimum frequency of visitation. Document the total missing record days and periods of unreliable record. Explain briefly. Example : Operational period is Seasonal (March October), minimum frequency of visitation being monthly. Fifteen (15) days of missing record July th were due to clock stoppage. Stilling well frozen until April 15 th. If applicable, state the number of level checks run to the station reference gauge. Describe the distribution method of gauge corrections. If levels were not used, you should explain why. Example : Three (3) level checks run to O/G [outside staff gauge] as per [Gauge History] form. G/C's [gauge corrections] distributed manually as per [Gauge Correction] form. Document level ties to station bench marks and explain any bench marks lost or destroyed during the year. Mention any new installations and particularly any datum shifts or adjustments made during the year. 3

227 Example : BM #NO88002 established June 18 th and tied to MBM [Master BM] #NO86001 as per NO66014 destroyed by loggers March Explain the methods used to obtain month-end levels for lakes and reservoirs. 4

228 4.0 DISCHARGE MEASUREMENTS Use the following procedure when completing the discharge measurements section of the Station Analysis form. Examples are provided for clarity. Form (Discharge or Miscellaneous Discharge Measurement) provides space to list the discharge measurements taken during the year. Document the total number and flow range of discharge measurements. Explain the types of discharge measurements taken (wading, bridge, boat, cableway, ice, etc.) and location of metering sections used during the year. If the sections were not consistent with those described on Station Description sheets, write an explanation. Example : Fifteen (15) measurements taken during the year ranging from m³/s. Four (4) ice measurements with winter rods, 5.0 m above bridge section; six (6) bridge measurements with 50 lb. wt. at U/S bridge rail; and the (5) wading seas with dry hand wading rod 5.0 m above bridge. Identify any unique or unusual flow conditions existing at a particular meter section and requiring special attention. Possible conditions include the adoption of standard angle coefficients, wet/dry line corrections, or adjustments made to compensate for ungauged inflow between a gauge and meter section. Example : Standard angle of.87 used to compute bridge measurement notes due to orientation of section. Document any major changes at the metering sections, such as the construction/removal of cableways, metering bridges or streambed aprons. Identify periods of use. Example : Cableway constructed 15.0 m above bridge section on July 15 th was used from August l st visit to year end. Explain any discharge measurements taken during the year and then not used. Also identify any measurements that have exceeded the historical maximum or minimum metered flow. Example : Cableway measurement of August l st (350 m³/s) was highest metered flow since start of record in

229 5.0 STAGE-DISCHARGE RELATIONSHIP State the type of control (natural, artificial or channel) and its relation to the gauge. Identify any factors or conditions that may have affected the control during the computation year. These factors include beaver dams, upstream or downstream regulation, shifting control, used growth or construction activity. Indicate time frames involved and explain computation methods (shifts, backwater curves, etc.) used during affected periods. Example : Control is formed by natural rapids 50 m below gauge. H-Q relation affected by backwater due to a log jam June 15 to July 10. Flows were computed during this period by stage-shifting based on hydrograph comparisons to tributary streams, local precipitation records and the June 29 discharge measurement as per Backwater Computations and Composite Hydrograph Treat ice periods separately. State the duration and range of backwater effect due to ice conditions. Describe the method used to compute flows as Backwater Method, Interpolated Discharge, Adjusted Discharge, etc. Example : Flows affected by backwater due to ice conditions January 1 st to April 12 th and from October 31 st to December 31 st. Backwater Computations documented on [Backwater Computations] sheets were by Effective Gauge Height Method as per 87/88 and 88/89 Winter Hydrograph forms ( ). State curve(s) used during the year by number, date and period of use. Example : Curve #4, dated 15-Mar-60, used for the year. Explain any curve extensions and methods used, such as slope-area, Stevens Method and Log Plots. Example : Curve #19 was extended.5 m above defined stage of 3.3 m by the log plot method. Curve #19 is the same as #18 below 1.5 m. 6

230 6.0 REMARKS Explain any name or location changes during the year. Example : Gauging station relocated 500 m upstream from previous site on June 15 th due to bridge construction. In the Stage Record Section, explain the basis for any estimated record identified as a missing record. Example : Missing record period July 15 th to 30 th determined by straight line interpolation based on hydrograph comparisons to nearby streams, MET records from NEARBY-TOWN and stage-range indicated on recorder chart. Identify records provided by other than primary sources, or records provided by another organization. This would include records obtained from Real Time Systems. Explain, if possible, acquisition/computation methods used. Example : Missing chart record July 10 th to August 10 th was filled using computer-generated 24 hr DATS aerial means gauge heights as supplied by the Lake of the Woods Secretariat in Hull, Quebec. Differentiate between International Stations and International Support Stations and identify the primary operators of the stations. Example : This is an International Gauging Station operated and maintained by the Water Survey of Canada. Explain any Historical Data Review(s). Document any revisions or adjustments made. Example : Data reviewed by District Data Control Section this year. Datum adjustment of m added to current work files to correct for transposition error on May 29, Identify periods of record computed by manual vs. automated methods such as STREAM, HOURLY, TIDAL or MANUAL computer programs. Example : All data processed by automated methods on a Sub-Office Digital Pro 380 computer using STREAM, with the exception of August th, which were computed manually because of a damaged recorder chart; data input as Updating Corrections to STREAM program. 7

231 7.0 SUMMARY Documentation of the Station Analysis form ( ) has been described through the use of example hydrometric stations. Throughout this lesson package the importance of this stage of the data computation and publication procedure has been stressed. These forms provide an essential tool to ensure that all data submitted for final publication have been computed to National Standards. The following items should be included on the Station Analysis Form : Stage Record Types of Instrumentation; Reference Gauges Changes; Station Upgrading Operational Period; Frequency of Observation and Performance Level Checks; Gauge Corrections Bench Marks and Datum Changes Month-end Stage of Lakes and Reservoirs Discharge Measurements Number, Range and Type of Measurements (Direct) Non-Conventional Measurements (Indirect) Unusual Conditions or Procedures Metering Section Changes Measurements Not Used and Extremes Stage Discharge Relationship Type of Control; Location, Stability and Shift Corrections Ice Period Computations (Backwater) Curves; Periods of Use Curve Extensions Remarks Name or Location Changes Basis for Estimates Contributed Record International Stations Historical Data Review Manual vs. Automated Methods. 8

232 8.0 MANUALS AND REFERENCES 8.1 FIELD MANUALS Environment Canada, Inland Waters Directorate, Water Resources Branch, Hydrometric Field Manual; Measurement of Stage, Ottawa, Canada, OFFICE MANUALS Hydrometric Field Manuals and Levelling, Ottawa, Canada, Automated Hydrometric Computation Procedures, Ottawa, Canada, October, HYDEX System Operations Manual, Fifth Edition, Ottawa, Canada, Manual of Hydrometric Data Computation and Publication Procedures, Fifth Edition, Ottawa, Canada, Manual of Hydrometric Data Review Procedures, Fifth Edition, Ottawa, Canada, Methods for the Estimation of Hydrometric Data, Fifth Edition, Ottawa, Canada, REFERENCES United States Geological Survey, Measurement and Computation of Streamflow: Volume 2, Computation of Discharge, Water-Supply Paper 2175, by S.E. Rantz et al., Washington, U.S.A.,

233 D A T A APPENDIX 1: FLOW CHART FOR THE COMPUTATION OF S T R E A M F L O W Figure 1: Flow chart for the Computation of Streamflow Data 10

234 11

235 APPENDIX 2: STATION DESCRIPTION FOR THE EXAMPLE STATION Figure 2: Station Description for the Example Station 12

236 APPENDIX 3: GAUGING STATION INVENTORY FOR THE EXAMPLE STATION Figure 3: Gauging Station Inventory for the Example Station 13

237 APPENDIX 4: GAUGING STATION INVENTORY UPDATING FORM (SAMPLE) Figure 4: Gauging Station Inventory Updating Form 14

238 APPENDIX 5: GAUGE HISTORY FORM FOR THE EXAMPLE STATION Figure 5: Gauge History Form 15

239 APPENDIX 6: DISCHARGE MEASUREMENT FORM FOR THE EXAMPLE STATION Figure 6: Discharge Measurements Form 16

240 APPENDIX 7: STAGE DISCHARGE TABLE FORM FOR THE EXAMPLE STATION Figure 7: Stage discharge Table 17

241 APPENDIX 8: STAGE DISCHARGE CURVE FOR THE EXAMPLE STATION Figure 8: Stage discharge Curve 18

242 APPENDIX 9: STAGE HYDROGRAPH FOR THE EXAMPLE STATION Figure 9: Stage Hydrograph 19

243 APPENDIX 10: DISCHARGE HYDROGRAPH FOR THE EXAMPLE STATION Figure 10: Discharge Hydrograph 20

244 APPENDIX 11: STREAMFLOW ANNUAL PAGE FOR THE EXAMPLE STATION Figure 11: Streamflow Annual Page 21

245 APPENDIX 12: BLANK STATION ANALYSIS FORM Figure 12: Blank Station Analysis Form 22

246 APPENDIX 13: STATION ANALYSIS FORM FOR THE EXAMPLE STATION Figure 13: Station Analysis Form 23

247 THE WATER SURVEY OF CANADA HYDROMETRIC TECHNICIAN CAREER DEVELOPMENT PROGRAM Lesson Package No. 23 Historical Data Review D.W. Kirk Water Survey of Canada Environment Canada Ottawa, Ontario Canada K1A 0H3

248 Copyright All rights reserved. Aussi disponible en français

249 TABLE OF CONTENTS 1.0 PURPOSE AND BACKGROUND OBJECTIVES GENERAL PROCEDURES DATA REVIEW PROCEDURES REVIEW OF THE DATA COMPUTATIONS PREPARATION OF THE REVIEW REPORT REVISIONS REVISIONS FILE UPDATING THE HISTORICAL DATA BANK (HYDAT) INFORMING USERS OF REVISIONS SUMMARY MANUALS AND REFERENCES OFFICE MANUALS REFERENCES... 9 APPENDIX A: BASIN REPORT List of Stations to be Reviewed Guelph District Atlantic Drainage Halifax District Atlantic Drainage Copy from Reference Index of Basin Bar Graph of Station Years of Record Sketch or Map Requests for Comparison Hydrographs Summary of Findings from Comparison Hydrograph Basin Comparisons Gauging Station Inventory Forms Historical Streamflow Summary Page APPENDIX B: REVIEW PROGRESS...19 Kennebecasis River at Norton APPENDIX C: STATION HISTORY Anderson River below Carnwath River, Station No. 10NC Birch River at Highway No. 7, Station No. 10ED Flat River at Cantung Camp, Station No. 10EA Prairie Creek at Cadillac Mine, Station No. 10EC APPENDIX D: HYDROGRAPHS Annual Discharge Hydrograph Comparison Hydrographs Full Scale (portion) Reduced Scale (20%) iii

250 3. Continuous Hydrograph Full Scale (portion) APPENDIX E: STAGE-DISCHARGE COMPOSITE CURVE SHEET South Nahanni River above Virginia Falls Willowlake River below Metandali Creek Back River above Hermann River APPENDIX F: COVER SHEET...30 APPENDIX G: TABLE OF CONTENTS Ellice River near the Mouth, Station No. 10QD Prairie Creek at Cadillac Mine, Station No. 10EC APPENDIX H: RECOMMENDATIONS Anderson River below Carnwath River, Station No. 10NC Mac Creek near the Mouth, Station No. 10EB Prairie Creek at Cadillac Mine, Station No. 10EC APPENDIX I: SUMMARY OF REVIEW Mac Creek near the Mouth, Station No. 10EB Northwest Miramichi River at Trout Brook Station No. 01BQ Prairie Creek at Cadillac Mine, Station No. 10EC Salmon River at. Salmon River Bridge, Station No. 01FJ Tetagouche River near West Bathurst, Station No. 01BJ APPENDIX J: SUMMARY OF REVISIONS TEXT PAGES Anderson River below Carnwath River, Station No. 10NC Back River above Hermann River, Station No. 10RC Birch River at Highway No. 7, Station No. 10ED Prairie Creek at Cadillac Mine, Station No. 10EC TABULAR PAGES (FORM ) Birch River at Highway No Flat River at Cantung Camp Little Southwest Miramichi River at Lyttleton Prairie Creek at Cadillac Mine MEANS AND EXTREMES Root River near the Mouth Willowlake River below Metahdali APPENDIX K: EXPLANATION OF REVISIONS Back River above Hermann River, Station No. 10RC Birch River at Highway No. 7, Station No. 10ED Flat River at Cantung Camp, Station No. 10EA Prairie Creek at Cadillac Mine, Station No. 10EC Upsalquitch River at Upsalquitch Station, No. 01BE iv

251 APPENDIX L: WORK SHEETS...54 Back River above Hermann River APPENDIX M: REVISIONS Daily Data Files Updating Birch River at Fort Liard Highway Tetagouche River Peaks File Updating MacCreek near the Mouth HYDEX File Updating (Gauging Station Inventory) Back River above Hermann River NC Stage Discharge Table Revision Anderson River below Carnwath River v

252 1.0 PURPOSE AND BACKGROUND When an Historical Data Review of hydrometric data is carried out, it involves a critical examination of all the original computations. These computations have previously been approved by an area head or possibly by a district engineer, using the best information that was available at the time. Review work should therefore be carried out by qualified staff only, and revisions made only with the approval of the regional engineer. Throughout this lesson module reference will be made to the Manual of Hydrometric Data Review Procedures, Fifth Edition, This is the most current manual available and although a few of the procedures are outdated resulting from the usage of in-house computer facilities, the guidelines are still valid. This manual is itself a procedures manual and requires very little assistance. It will be referred to constantly in this training module. It should also be noted that the current review procedures involve a reexamination of all the historical computations for the station under review. The data are not subjected to statistical analysis (by computer) as part of the review procedures, although analysis may be used to select stations for an historical review and software will undoubtedly be written in the future which will assist review work. We should distinguish between the following two types of revisions to historical data : a. In the first case normal hydrometric computation practice requires that anomalies in historical records, exposed by current findings, be revised. For example if new high water measurements are obtained which redefine the upper end of the stage discharge relationship, then the historical stage discharge curves should be examined and the records revised accordingly. This procedure is explained in section 9 of the Manual of Hydrometric Data Review Procedures, but it is not necessary to examine this section for historical review purposes. b. In the second case the original historical records are being reviewed to see if there are any anomalies. This is the Historical Data Review which is included in this training package and which is described in the Manual of Hydrometric Data Review Procedures. 1

253 2.0 OBJECTIVES This training package is to be presented to technicians at the senior EG-ESS-6 level. The objectives of the training are as follows : 1. to become familiar with the criteria and procedures for reviewing and revising WRB hydrometric data as explained in the Manual of Hydrometric Data Review Procedures. 2. to understand why past data are reviewed and revised. 3. to gain knowledge of obsolete techniques and instrumentation and how these may affect the reliability of the records. 4. to learn what to watch for in current work and to make recommendations to improve current work by identifying errors in historical data. 5. to learn the procedures for the approval of revisions, updating of data files at headquarters and the preparation of a Data Review Report. This training package and the instruction manual have been developed for discharge and water level data only. The procedures for sediment data are discussed under separate packages. 2

254 3.0 GENERAL PROCEDURES Review sections 1 Introduction and 2 General Hydrometric Data Review Procedures in the Manual of Hydrometric Data Review Procedures, Fifth Edition, hereafter referred to as the manual. Note historical data reviews are no longer conducted under the general supervision of the Data Control Section in Ottawa. The authority for conducting and approving historical revisions has been transferred to the Regional Offices. Naturally these reviews will be performed following the national standards as outlined in the latest manual. The cover sheet in the review report should show the signatures of the regional engineer and area engineer, authorizing approval of the revisions. A copy of this cover sheet should be sent to the Data Control Section in Ottawa when the revisions to the HYDAT files are sent, so that they will be informed as to why changes are being made. In the manual, section 2.2 explains the criteria for revising streamflow data. These criteria are general rules which have been set for expediency. A data review of all values would be an exhaustive task, therefore spot checking is used only for daily computations to expose significant errors. Minor errors need not be revised according to the criteria in the manual although they should be identified in the report. Some reviewers prefer to revise all errors which are discovered regardless of criteria. However, there should be a consistent approach to prepare a review report according to regional policy. The procedure for storing data on the SAVE tapes has been changed since the writing of the manual in 1980 (section 2.7). The SAVE data are now retained in the regional offices on disk so it is possible that a revision file for a particular station number and year could be appended to the original data (but identified) or perhaps merged in an annual revisions file. A new standard procedure has not yet been established. 3

255 4.0 DATA REVIEW PROCEDURES 4.1 REVIEW OF THE DATA COMPUTATIONS Follow the procedures step by step as outlined in the manual, section 3. Additional comments follow : a. The trainee should know where all these records are retained in the office. If they are stored outside the office the trainee should learn how the information can be retrieved. A supply of forms for the review should also be assembled. Some computation forms may be required if records have to be recomputed. Revision forms for the data bank in Ottawa (FLOW, PEAKS, HYDEX) may also be required. Only two forms are specifically used for the review report, as follows : Review Progress Summary of Revisions Before proceeding any further with the data review of a particular station, turn to section 5 in the manual, entitled Basin Report. This section explains how an entire basin should be examined before an individual station is reviewed. Even if only one station is to be reviewed, it is a good idea to assemble this information and prepare the sketches as indicated. This procedure will ensure making use of all available data for comparison and estimation. Section 6 provides instructions on how to order comparison hydrographs from Ottawa. If a Basin Report is already available then it should be updated during a data review at a station. If the report is not available, then one should be prepared following the steps indicated. See samples in Appendix A. b. The review progress form is a checklist which is used during the review to ensure that each step in the review is completed. This form is included in the back of the review report when it is completed. See sample in Appendix B. c. The station history is completed on a blank sheet of paper which allows variable length entries under the headings indicated. This information is gleened out of the station work files if they have been properly documented. See samples in Appendix C. d. The annual discharge hydrographs of historical data can be plotted from the historical data base stored on magnetic tape at the Computer Services Centre in Ottawa. Since these may take two weeks for delivery, ordering these hydrographs should be one of the earlier steps in the review process. (Most regions are now able to run their own hydrograph retrievals consult your data control staff.) The discharge measurements will be plotted on these annual hydrographs by hand and the hydrographs will be folded and filed in the review report. Revisions are also to be plotted on these hydrographs. See samples in Appendix D. The comparison hydrographs may also be ordered from Ottawa or retrieved by your data control staff. They can be retrieved at a reduced scale for a preliminary examination and then at full scale for questionable periods. Note that as previously mentioned in (a), chapter 6 in the manual explains how to complete Request for comparison hydrographs. Section 5 offers suggestions on how to select stations and years for comparison purposes. See samples in Appendix D. The effective use of comparison hydrographs is a very useful tool for exposing significant differences in 4

256 runoff. One technique which is useful on a river or river system with two or more stations is to subtract upstream station flows from a downstream station. The resulting flows, which are plotted, represent the ungauged inflow between the stations. Often negative ungauged inflow or spikes in the hydrograph will illustrate periods of questionable data, which may have to be recalculated. e. The examination of the stage discharge curves by plotting many (or all) of the curves and measurements on one sheet is an extremely important tool for verifying the validity of the various HQ relationships. This plotting is done by hand on the appropriate curve sheets, although in the future software will be prepared to assist in this task. These curves will be reviewed (f iv) and revisions plotted and identified on this composite curve sheet. See samples in Appendix E. f. Once the preliminary work has been done, follow the prescribed steps to conduct spot checks on the computations and when making revisions to questionable discharge data. g. Follow the procedures as described in the manual, sections (g) to (l). Samples of the various forms are included in Appendix F to M. 4.2 PREPARATION OF THE REVIEW REPORT Section 4 in the manual lists the contents of the data review report in the order that they should appear. These contents have been discussed in the previous section. 5

257 5.0 REVISIONS 5.1 REVISIONS FILE Section 8 in the manual explains how each hydrometric station should have a file folder or Revisions File where all revisions to historical data are documented. The contents of the Revisions file are indicated in full detail in the manual. 5.2 UPDATING THE HISTORICAL DATA BANK (HYDAT) Having reviewed the data, written the review report and received approval of the report as indicated by the appropriate signatures on the cover sheet, it is then necessary to ensure that all revisions are updated on the National Hydrometric Data Bank (HYDAT). This proceedes as follows : a. Enter revised discharge/water level values : From the review report all the revised values are keyed into a disk file on the PDP11/44 following the standard input formats for FLOWS and PEAKS. The extreme codes should also be entered if they have been revised. Ensure that symbol codes are also entered, although the symbol R should not be included. b. Transfer revisions to Data Control Section, Ottawa : The revisions should be transferred to Ottawa in two ways : i. A copy of the revisions from the report, including HYDEX and REMARKS changes and a copy of the cover sheet should be mailed to Ottawa. This will indicate to the Data Control Section that the values are revisions and require a revisions update (this adds the R symbol to the values when updated onto tape). or ii. Transfer the disk file from the regional PDP11/44 to Ottawa via datapac and notify the DCS of the transfer. Note steps (a) and (b) are done in cooperation with the regional Data Control Section. c. Update HYDAT The Data Control Section will update the data bank in Ottawa. The HYDEX/REMARKS files are updated on a monthly basis; the FLOW, LEVELS and PEAKS files are updated approximately annually. There will therefore be a delay before the region is notified that the updates have been completed. The updated daily and instantaneous values will include the value R stored on tape. d. Listings to Regions Once the revisions have been updated on HYDAT, listings will be returned to the regional Data Control Staff who will ensure that the revisions are correct on tape and the listings will be filed in the appropriate places. 6

258 These listings include : i. HYDEX Gauging Station Inventory Listings ii. FLOW or LEVELS Provisional Listings that show the R symbol on the revised daily or instantaneous values. These listings, once verified, are to be filed in the Revisions File. iii. FLOW or LEVELS Historical Listings that do not contain the R symbol and which are generally used for data requests. These are filed in the Blue Books. 5.3 INFORMING USERS OF REVISIONS The revised daily values are not published in books, but users are informed of the revisions in four ways : a. The HYDEX file is updated to show that the station has been reviewed to a specific year. This information is indicated in the Surface Water Data Reference Index. b. The Historical Streamflow (Water Level) Summary publication displays the symbol R beside any monthly or annual mean that has been revised since the previous publication. Note that this publication is produced every two years and that the R symbols will be deleted from the tape after the publication is produced. c. Microfiche are produced annually which show all daily and instantaneous values for the entire period of record. Since these are produced from the HYDAT tapes, they will show all the R symbols that are stored on tape. d. Users who request data on magnetic tape will receive all the latest values and symbols stored on file, and also receive a listing that shows which stations and years contain revisions. 7

259 6.0 SUMMARY By completing this lesson package, the participant will have had the experience of completing the data review of a station with the instructor. The procedures as outlined in the Manual of Hydrometric Review Procedures will have been discussed and followed during the review and will now be understood. The participant will also be prepared to develop a Data Review Report having examined the examples in this training package. Each station is unique and the report will therefore have been prepared to include the forms and pages necessary to explain the particular station reviewed. Perhaps the greatest benefit to the participant will be the experience of investigating the computation procedures used by technicians and engineers decades ago. An examination of these earlier computation techniques has revealed what knowledge was available at the time of the original computations, how the decisions were made at the time, and whether or not those decisions are valid in the light of the knowledge now available. This experience will reinforce the necessity of documenting decisions made through current computations for future studies. 8

260 7.0 MANUALS AND REFERENCES 7.1 OFFICE MANUALS Environment Canada (1980), Manual of Hydrometric Data Review Procedures, Fifth Edition, Inland Waters Directorate, Internal Report, Ottawa. 7.2 REFERENCES Canadian Standards Association (1979), Canadian Metric Practice Guide, CSA Standard Z , Rexdale. 9

261 APPENDIX A: BASIN REPORT 1. LIST OF STATIONS TO BE REVIEWED Guelph District Atlantic Drainage Station Number Station Name St. Lawrence Ottawa River Drainage Basin Period of Record Total Sta. Years Review Comp. to 02JE003 Ottawa River near Timiskaming JC003 Englehart River (West Branch) near Charlton Years to be Rev JD006 Montreal River at Indian Chute JD004 Montreal River at Elk Lake JE014 Mattawa River near Rutherglen KB001 Petawawa River near Rutherglen KC003 Bonnechere River at Renfrew KC009 Bonnechere River near Castleford KD006 Madawaska River at Whitney KD001 Madawaska River at Madawaska KD004 Madawaska River at Palmer Rapids KD005 Madawaska River near Madawaska KE002 Madawaska River near Arnprior 21 22, KD002 York River near Bancroft KF006 Mississippi River at Appleton LA002 Rideau River at Ottawa LA001 Tay River near Glen Tay 15 19, LB007 South Nation River at Spencerville LB005 South Nation River near Plantagenet Springs MC001 Raisin River at Williamstown Total

262 Halifax District Atlantic Drainage Station Number Station Name Saint John River Drainage Basin Period of Record Total Sta. Years Review Comp. to 01AF002 Saint John River at Grand Falls AJ001 Saint John River at East Florenceville AK002 Saint John River at Pokiok AD003 St. Francis River at Outlet of Glasier Lake AF003 Green River near Riviere-Verte AH002 Tobique River at Riley Brook AH003 Tobique River at Plaster Rock AH001 Tobique River at Arthurette AK001 Shogomoc Stream near Trans Canada Highway 18 41, AK005 North Nashwaaksis Stream near Royal Road AL002 Nashwaak River at Durham Bridge AM001 Northwest Oromocto River at Tracy AP002 Canaan River at East Canaan 25 41, AP004 Kennebecasis River at Apohaqui AP001 Kennebecasis River at Norton Years to be Rev Total 235 Station Number Station Name New Brunswick Bay of Fundy Drainage Basin Period of Record Total Sta. Years Review Comp. to 0lAQ001 Lepreau River at Lepreau lAQ002 Magaguadavic River at Elmcroft 17 33, AQ005 Magaguadavic River at Second Falls IBU002 Petitcodiac River near Petitcodiac IBU003 Turtle Creek at Turtle Creek IBV006 Point Wolf River at Fundy National Park Years to be Rev BV005 Ratcliffe Brook below Otter Lake Total

263 12

264 2. COPY FROM REFERENCE INDEX OF BASIN Figure 1: Copy from Reference Index of Basin 3. BAR GRAPH OF STATION YEARS OF RECORD Figure 2: New Brunswick Bay of Fundy Drainage Basin 13

265 Figure 3: New Brunswick Bay of Fundy Drainage Basin (2) Figure 4: New Brunswick Gulf of St. Lawrence Drainage Basin Figure 5: Bar Graph of Years Revised 14

266 4. SKETCH OR MAP Figure 6: Sketch Figure 7: Sketch Figure 8: Liard River Basin Schematic of Selected Gauging Stations 15

267 5. REQUESTS FOR COMPARISON HYDROGRAPHS Figure 9: Request for Comparison Hydrographs 6. SUMMARY OF FINDINGS FROM COMPARISON HYDROGRAPH 7. BASIN COMPARISONS Figure 10: Basin Comparison of Annual Means Figure 11: Basin Comparison of Monthly Means 16

268 8. GAUGING STATION INVENTORY FORMS WATER SURVEY OF CANADA GAUGING STATION INVENTORY 01 STATION NO. 05LJO07 NOV PAGE 1 WINNIPEG, MAN. 02 STATION NAME: TURTLE RIVER NEAR LAURIER 03 REGION: WINNIPEG 04 STATUS: A (ACTIVE) 05 INTERNATIONAL 06 PROV., TERR. OR STATE: MAN 07 CO-ORDINATES: LAT LONG DRAINAGE AREA: KM2 09 LOCATION: 6.6 KM NORTH OF THE JCT OF HWY 5 AND P.R. 480, THEN 1.6 KM W 10 TRIBUTARY TO DAUPHIN LAKE 11 LEGAL LAND DESCRIPTION: NW Wl 12 TYPE OF RECORDER: 13 GRAPHICAL X 17 TYPE OF MANUAL GAUGE : 22 OTHER INSTALLATIONS: 14 DIGITAL 18 STAFF X 23 CABLEWAY X 15 FLOAT ACTIVATED 19 CANTILEVER 24 TELEMARK 16 OTHER (SPECIFY) 8 20 WIRE WEIGHT X 25 ARTIFICIAL CONTROL SERVO-MANOMETER 21 OTHER (SPECIFY) 26 OTHER (SPECIFY) 27 TYPE OF RECORD Q 31 RECORDS OBTAINED: 41 GAUGE DATUM: 28 TYPE OF GAUGE R M M 42 SEVERAL DATUMS 29 LOCATED AT STA. NO M S 43 CURRENT DATUM 010 ASSUMED DATUM 30 OPERATION SCHEDULE S Q M M 44 OTHER DATUM Q M M 45 CONVERSION FACTOR: Q M S R S 46 STANDARD PERIOD SEDIMENT DATA D 39 MAR-OCT 48 WATER QUALITY DATA RESERVOIR CONTENTS 50 CONT. WATER TEMP. 53 NATURAL FLOW X 56 DATA REVIEWED x ITEMS MONTHLY MEANS ONLY 54 REGULATED 57 REV. TO YEAR 1970 NOT USED AT THIS TIME 52 DATA PRIOR TO REGULATION BEGAN NOT PUB. BY WSC 63 DATA COLLECTED BY OTHER AGENCY 67 RESPONSIBILITY CLASSIFICATION: 64 CONTRIBUTED 68 COSTING ARRANGEMENT H FEDERAL-PROVINCIAL 3. REG. WATER QUANTITY INVENT 65 AVAILABLE FROM 69 OPERATING AGENCY A WATER SURVEY OF CANADA 66 NAME OF AGENCY: 70 NAME OF OPER. AGENCY 71 REMOTE ACCESS 72 REMARKS FOR ANNUAL SURFACE WATER DATA PUBLICATION: 73 REMARKS FOR HISTORICAL STREAMFLOW SUMMARY PUBLICATION: 74 REMARKS FOR HISTORICAL WATER LEVELS SUMMARY PUBLICATION: 75 GENERAL REMARKS: 76 REPLACES FORM DATED 77 FOR OTTAWA OR REGIONAL USE: HYDEX MAPS REF. INDEX NOV PREPARED BY CHECKED BY 17

269 9. HISTORICAL STREAMFLOW SUMMARY PAGE Figure 12: Historical Streamflow Summary Page 18

270 APPENDIX B: REVIEW PROGRESS KENNEBECASIS RIVER AT NORTON Figure 13: Review Progress 19

271 APPENDIX C: STATION HISTORY 1. ANDERSON RIVER BELOW CARNWATH RIVER, STATION NO. 10NC001 Period of Record : This station was established by E. D. Fowler in However, there is no detailed documentation on file. Daily discharge records are available from September 28, 1969 to date. Location : Lat 68º 38' 39" Long 128º 25' 30", as determined by the PAL computer program on January 2, 1986 corrected from 68º 38' 00", 128º 24' 30" on right bank, 220 air-km NE of Inuvik, 31 air-km below confluence with Carnwath River, and 100 m above small tributary Drainage Area : Discharge Measurements : Type of Gauge : Elevation of Gauge Datum : Bench Marks : km² corrected from km², mi.² as determined by digitizing on January 2, 1986 by boat, by wading or from ice cover near gauge Stevens A-35 recorder, activated by a 35-ft (11-m) range servomanometer and housed in a 3.7 m x 4.9 m (12 ft x 16 ft) Armco cabin the pen is set to the gauge height as obtained by levelling on each visit water level records are not obtained during winter periods cabin was moved about 6 m (20 ft) during high water in June m (70.00 ft) BM #1 Bolt in spruce tree at north end of cabin Elevation m ( ft) BM #2 Bolt in cone-shaped stump behind cabin Elevation m ( ft) SIBM #3 30 ft NW of cabin Elevation ft destroyed during high water in June 1972 SIBM #4 20 ft N of S.I.B.M. No. 3 Elevation ft destroyed during high water in June 1972 Remarks : a. Rain gauge was installed in 1969 but readings were not tabulated b. Water quality samples have been taken since at least 1979 c. Three ground rod bench marks were installed to refusal in August 1986 d. A Data Collection Platform was installed in

272 2. BIRCH RIVER AT HIGHWAY NO. 7, STATION NO. 10ED003 Period of Record : This station was established by the Calgary Office in 1974 and daily discharges are available from October 16, 1974 to date. Location : Lat. 61º 20' 13", Long. 122º 05' 12" corrected from , in 1986 on right bank, 130 m below highway bridge and 2.5 km above confluence with the Liard River Drainage Area : 542 km² (337 mi.²) natural flow corrected from 505 km² by digitizing in 1986 Discharge Measurements : by wading, from an ice cover or from a bridge the HQ relation was altered significantly during August 1982 when the bridge contractor removed rocks from the control for pier rip rap Type of Gauge : Elevation of Gauge Datum : Bench Marks : Stevens A71 analog recorder activated by a 35-ft (10.67-m) range servomanometer, housed in a x 81 (1.62 x 2.44 m) Brytex shelter m (90.00 ft) BM 74-1 Elevation m ( ft) established October 16, 1974 head of spike in large spruce tree m (1 ft) above ground directly across river from gauge BM 74-2 Elevation m (97.40 ft) established October 16, 1974 head of spike near base of spruce tree across river from gauge BM 83-1 Elevation m established June 1, 1983 ground rod 10 m south of gauge BM 83-2 Elevation m established June 22, 1983 ground rod 4 m south of gauge Remarks : formerly called at Fort Liard Highway 21

273 22

274 3. FLAT RIVER AT CANTUNG CAMP, STATION NO. 10EA002 Period of Record : This station was established by the Vancouver office in 1959 and discontinued in Daily discharges were computed for periods of varying length from 1960 to 1962; these records were revised by the Calgary Office in However, in this review the daily discharge records were considered unreliable and were removed from the FLOW file. Thirteen miscellaneous discharge measurements were obtained from 1959 to This station was re-established on July 23, 1973 by the Calgary Office (Fort Simpson sub-office) and daily discharges are now available from July 23, 1973 to date (missing records for 1974, 1976, 1982 and 1984 were completed in this review). Location A : 1959 to 1963 lat. 61º 57' 40", long. 128º 13' 00" on right bank, 3/4 mile (1.2 km) below pumphouse (see March 13, 1963 meter notes) Drainage Area : 52 mi.² low flows affected by pumping diversions Discharge Measurements : Type of Gauge : Elevation of Gauge Datum : Bench Marks : Remarks : Location B : Drainage Area : Discharge Measurements : by wading, from an ice cover or from a bridge 8 under ice conditions, 5 during open water HQ relation is not defined chain gauge, attached to a 10-inch spruce (see BM-1) 0.00 ft observer appointed March 30, 1960 BM-1 established March 30, 1960; elev ft head of 1011 spike in base of 10" spruce, to which chain gauge is attached BM-2 established March 30, 1960; elev ft head of 10" spike in base of 1211 spruce, 8 ft upstream from BM-1 BM-3 established August 10, 1980; elev ft painted boulder at end of airstrip, 500 ft upstream from camp buildings, beside garbage dump daily discharge records at this location are considered unreliable (see Explanation of Revisions). July 23, 1973 to date lat. 61º 58' 05", long. 128º 13' 40" corrected from , by digitizing in 1986 on right bank, in mine pumphouse from July 23, 1973 to July 24, 1982 on right bank, in gauge shelter beside mine pumphouse from July 24, 1982 to date 30 m upstream from rock weir 155 km² (60 mi.²) corrected from 152 km2 (58.7 mi. 2 ) by digitizing from 1: maps in 1986 low flows affected by pumping diversion by wading, from an ice cover, from boat or bridge 23

275 HQ relation often altered by bulldozer activity on weir 4. PRAIRIE CREEK AT CADILLAC MINE, STATION NO. 10EC002 Period of Record : This station was established by the Calgary office in Daily discharges are available from September 20, 1974 to date. Location : Lat. 61º 33' 30", Long. 124º 48' 45" corrected from ", in 1986 on right bank below mine airstrip, 184 air-km W of Fort Simpson and 45 river-km above confluence with South Nahanni River Drainage Area : 495 km² natural flow Discharge Measurements : by wading or from ice cover at or near the gauge water too swift for wading and too shallow for boat above 25 m³/s slope-area measurement (187 m³/s) on June 3, 1977 very low velocities during some winter measurements Type of Gauge : Stevens A-71 analog recorder activated by a 35-ft range servomanometer, housed in a x 81 metal shelter Elevation of Gauge Datum m (90.00 ft) : Bench Marks : BM No Elevation m ( ft) established September 19, 1974 paint mark on bedrock, 5 m south of gauge BM No Elevation m ( ft) established September 29, 1974 paint mark on bedrock, 2 m from

276 APPENDIX D: HYDROGRAPHS 1. ANNUAL DISCHARGE HYDROGRAPH Figure 14: Annual discharge hydrograph at full scale 2. COMPARISON HYDROGRAPHS Figure 15 (a): Request for comparison hydrographs form Figure 15 (b): Request for comparison hydrographs form (continued) 25

277 2.1 Full Scale (portion) Figure 16: Comparison hydrograph at full-scale 2.2 Reduced Scale (20%) Figure 17: Comparison hydrograph displaying revisions reduced to 20% scale 26

278 3. CONTINUOUS HYDROGRAPH 3.1 Full Scale (portion) Figure 19: Continuous hydrograph at full scale Figure 18: Continuous hydrograph at full scale. Revision indicated by dotted line 27

279 APPENDIX E: STAGE-DISCHARGE COMPOSITE CURVE SHEET 1. SOUTH NAHANNI RIVER ABOVE VIRGINIA FALLS Figure 20: Composite Curve Sheet (Metric Units) 2. WILLOWLAKE RIVER BELOW METANDALI CREEK Figure 21: Composite Curve Sheet (Imperial Units) 28

280 3. BACK RIVER ABOVE HERMANN RIVER Figure 22: Composite Curve Sheet (Imperial Units) 29

281 APPENDIX F: COVER SHEET Report on Review of Hydrometric Survey Data to 1970 for Renous River at McGraw Brook Station No. 01BO002 Prepared in accordance with Manual of Hydrometric Data Review Procedures, dated December 1 st, 1972, by : J.W. Clarke, D.B. Pope and A. Creighton March 26,

282 APPENDIX G: TABLE OF CONTENTS 1. ELLICE RIVER NEAR THE MOUTH, STATION NO. 10QD001 CONTENTS Page Summary of Review...3 Recommendations...5 Summary of Revisions...6 Station History...12 Explanation of Revisions...14 Composite Curve Sheets Imperial Units...23 Metric Units Revision Worksheets HYDEX File Update FLOW File Updates Summary of Means and Extremes Before Revision After Revision Hydrographs (1.0 Scale, Worksheets) Including 10QC001 and 10RA to to to Hydrograph (0.2 Scale, 1970 to 1984) Showing original and Revised Data

283 2. PRAIRIE CREEK AT CADILLAC MINE, STATION NO. 10EC002 CONTENTS Page Summary of Review... 3 Recommendations... 5 Summary of Revisions... 6 Station History Explanation of Revisions Composite Curve Sheets Imperial Units Metric Units Revision Worksheets HYDEX File Update FLOW File Updates Summary of Means and Extremes Before Revision After Revision Hydrographs (1.0 Scale, Worksheets) Including 10QC001 and 10RA to to to Hydrograph (0.2 Scale, 1970 to 1984) Showing original and Revised Data

284 APPENDIX H: RECOMMENDATIONS 1. ANDERSON RIVER BELOW CARNWATH RIVER, STATION NO. 10NC001 RECOMMENDATIONS 1. Change elevation of Gauge Datum to m to facilitate field and office work. 2. Update Station Description. 3. The DCP installation should include an air temperature probe and results tabulated and compared graphically with those at I nuvik. 4. Evaluate accuracy of winter measurements because of slush problems, angle of Clow, current meter freezing up, etc., e.g. 1978, 1979, 1981; and revise records if appropriate. 5. Obtain gauge height records and discharge measurements during the freeze-up period, if feasible, to confirm (or otherwise) that there is a sharp decrease in flow then a subsequent recovery, followed by a smooth recession during the winter period. 6. Review data for 1982 to date for the Carnwath River below Andrew River, Station No. 10NA001 to ensure agreement with Station No. 10NC Establish a gauging station on the Anderson River above Carnwath River to obtain a better understanding of the hydrologic characteristics of the predominantly lake-fed component of the Anderson River. 2. MAC CREEK NEAR THE MOUTH, STATION NO. 10EB002 RECOMMENDATIONS 1. The HQ relation is unstable. Therefore, more discharge measurements are required every year to define the daily shift correction distribution more accurately and especially to define the HW range above 25 m³/s. 2. Ensure that any future observations of nil or very low flow are well-documented, especially if very low velocities are encountered. 3. Review data again after HW measurements above 25 m³/s have been obtained. 3. PRAIRIE CREEK AT CADILLAC MINE, STATION NO. 10EC002 RECOMMENDATIONS The stage discharge relation is very unstable and the shift correction distribution is poorly-defined. Therefore, the following alternatives are suggested to improve future records : 33

285 1. Obtain more discharge measurements at all stages (especially during and after high-water flows) to define the shift corrections, which should be applied on a stage basis where applicable or on a linear time basis; a copy of the daily shift correction distribution (from STREAM) should be retained on the work file, OR 2. Re-locate the station to a site where a more stable stage discharge relation can be established and where orifice movement is less severe. 34

286 APPENDIX I: SUMMARY OF REVIEW 1. MAC CREEK NEAR THE MOUTH, STATION NO. 10EB002 Data were collected and computed by the Calgary Office (Fort Simpson sub-office), from 1978 to 1980; this responsibility was transferred to the Yellowknife office in The STREAM computer program has been used since 1978 and data have been collected and computed in metric units since Gauge height records were obtained from a Stevens A-35 analog recorder activated by a servomanometer, usually during open-water periods only. The stage discharge relation is unstable and is defined by discharge measurements in about a 15 20% band there are no discharge measurements above 23 m³/s. A detailed year-by-year examination of the records was carried out and explanations are given herein. Revisions were tabulated and submitted to Ottawa where temporary data files were set up to provide plots and listings. original documents were not corrected and the HYDEX file was not updated pending final approval by Yellowknife and Ottawa. Remarks This station is operated in co-operation with the Province of New Brunswick to obtain water supply information. The flow is natural and the control is relatively stable with only minor shifting from time to time. 2. NORTHWEST MIRAMICHI RIVER AT TROUT BROOK STATION NO. 01BQ001 Extent of Revisions : Fifteen symbol changes were made affecting 7 months in 5 years. Four other maximum instantaneous discharges were considered estimated. High stages in 1963 and 1964 together with instantaneous peaks were revised in Conclusions : The stage discharge relationship is well defined below 8,000 cfs but above this, discharges quoted should be treated as estimates due to the lack of discharge measurements. At a later date, when discharge measurements above 8,000 cfs have been obtained, a second evaluation of the high water curves may indicate the need for revision. Data from this station is considered reliable except during extreme high-water. In 1982 a further review was made on this station and since curve No. 8 appears to be fairly well defined up to 11,000 cfs, it was decided that the symbol E should be deleted from high stages in 1963, 1972 and High flows during 1963 and 1964 were revised using curve No. 8, affecting all discharges above 4,000 cfs. 3. PRAIRIE CREEK AT CADILLAC MINE, STATION NO. 10EC002 Data were collected and computed by the Calgary Office (Fort Simpson sub-office) from 1974 to 1980; this responsibility was transferred to the Yellowknife office in The STREAM computer program has been used since 1975 and data have been collected and computed in metric units since Gauge height records were obtained from a Stevens A-71 analog recorder activated by a servomanometer, usually 35

287 during opdn-water periods only. There usually was significant orifice movement during high flows. Discharge measurements were obtained at or near the gauge by wading or from an ice cover. open-water measurements were not obtained above 25 m³/s because flow was too fast to wade and too shallow for boat. The HQ relation is very unstable and is defined at HW only by a slope-area measurement of 187 m³/s on June 3, Shift corrections were applied on a linear time basis between measurements. Very low velocities were observed at some winter measurements and therefore of debatable accuracy. A detailed year-by-year examination of the records was carried out and explanations are given herein. Revisions were tabulated and submitted to Ottawa where temporary data files were set up to provide plots and listings. original documents were not corrected and the HYDEX file was not updated pending final approval by Yellowknife and Ottawa. Remarks This station was establ ished in September of 1965 and was rebuilt in June of 1972 after the highway and bridge had been improved. At this time, a cableway was also built. No change in datum resulted. The presence of ice in winter and aquatic growth in summer significantly affect the data gathered at this site. 4. SALMON RIVER AT. SALMON RIVER BRIDGE, STATION NO. 01FJ001 Extent of Revisions : 2 maximum instantaneous discharge, were revised. 2 maximum daily discharges were revised. 2 minimum daily discharges were revised. 577 daily discharges affecting 22 months in 4 years were revised. These revisions were deemed necessary due to the effects of ice and weeds. Conclusions : Discharges quoted below 800 cfs are considered reliable due to the availability of numerous discharge measurements. Between 800 cfs and 2000 cfs only 4 discharge measurements have been obtained and several of these did not fall on any of the discharge curves. By applying shift corrections, the record below 2000 cfs, for the entire Period of record, has been adjusted and can, therefore be considered reliable. Above 2000 cfs there are, no discharge measurements. Although there are several different high water curves no one curve is considered more reliable than another and therefore, no revision has been applied to this record. Discharges quoted above 2000 cfs should be used with caution. In the opinion of the reviewer, after the revisions recommended by this report are applied, the record for the entire review period is as reliable as can he obtained at this station. This comment is made considering the fact that stage record is significantly affected by ice and weeds (up to 50%) and that the manual measurement of streamflow is also made difficult by the same conditions. Distribution of the shift and backwater corrections are made extremely difficult to interpret due to flash 36

288 fluctuations in discharge. It is recommended that if discharge measurements above 2000 cfs ate obtained, that the stage discharge relationship be re-examined. Remarks It should be noted that for the two periods of existing records only one gauge location was established. During the earliest period of record, , many of the ice periods were not clearly defined in the records and these periods are being submitted as corrections to the FLOW file. 5. TETAGOUCHE RIVER NEAR WEST BATHURST, STATION NO. 01BJ001 Extent of Revisions : 77 daily revisions affecting 5 months in 3 years symbols B for ice and 202 symbols A for manual gauge are being added to the FLOW file. Conclusions : For the earliest period of record, 1922 to 1933, the stage discharge relationship was well defined at all stages and the daily discharges for this period should be reliable. For the latest period of record, 1951 to 1970, the low and medium water stages were well defined at all stages and the daily discharges for this period should be reliable. For the latest period of record, 1951 to 1970, the low and medium water stages were well defined, but the upper extremities of the stage discharge curves, above 2,000 cfs, are not too well defined and daily discharges above this flow may be questionable. A concentrated effort should be made to acquire some flow measurements above 2,000 cfs to tic in the upper extremity of existing stage discharge curves. As a further attempt to understand the behavior of the stage discharge relationship at high water five recent high water measurements, of May 6, 1971, May 1, 1973, May 16, 1974, May 7, 1979 and April 29, 1982 were plotted on the curve sheet. No concrete decisions could be reached except to say that there is a considerable scatter of highwater measurements which indicates a shifting control and that extra verticals may be required when taking measurements to ensure accuracy. 37

289 APPENDIX J: SUMMARY OF REVISIONS 1. TEXT PAGES 1.1 Anderson River below Carnwath River, Station No. 10NC001 Period of Record Reviewed : 1969 to 1984 Daily discharges are available from September 28, 1969 to date. Estimates for missing periods and the shape of the ascending limb, and the timing and magnitude of flows during break-up were based mainly on Inuvik temperatures, HW marks and the recession shape after break-up (see hydrographs). A revision (or estimate) of some type was made to every year of record from 1969 to Revisions were made to 1764 days of record involving 73 of the 183 months; this includes the estimation of missing data for 362 days involving 18 of the 73 months, and 7 years. Revisions (other than estimates for missing periods) were required for various reasons : a. logarithmic recession (not arithmetic interpolation) during winter periods, b. HW and LW HQ revisions, c. shape of ascending limb during break-up, d. timing and magnitude of flows during break-up, e. shape of recession after break-up, f. revised peaks based on HW marks, g. keypunching errors, h. interpretation of BW corrections, and i. invalid maximum instantaneous discharges. The most significant revision was made to 1972 data. The historical peak for the period 1970 to 1984 occurred on June 2 (3000 E m/s) and was not documented previously. It is fairly-well substantiated by a HW mark of m and discharge measurements at about 1300 and 1900 m/s. Also, missing daily discharges for June and July were estimated to complete the year. 1.2 Back River above Hermann River, Station No. 10RC001 Period of Record Reviewed : 1960 to 1984 This station was established as a miscellaneous discharge measurement site in 1960 and partial daily records were obtained from but are mostly unreliable and are considered of little value statistically and therefore were deleted from the FLOW file. The HYDEX File Update shows miscellaneous measurements from and continuous daily discharges from 1965 to date. 38

290 Baker Lake temperatures were used as a guide where required to assess the records. The shape (slope) of the ascending limb during break-up for most years for which a revision was made was assumed to be similar to the one for 1983 during the Spring Field Survey. The use of a smooth logarithmic recession for the winter period from October to May was adopted for all years in favor of the BW Curve or Effective Gauge Height methods. Several winter measurements were considered too low, some too high and others were discarded to accommodate this interpretation, which can be substantiated upon examination of plot of Backwater Curves for Nos. 47, the Composite Plot of Winter Measurements, vs Date and the Composite Plot of Winter Measurements vs Gauge Height. Revisions were required for various reasons : a. logarithmic recession (riot arithmetic interpolation) during winter periods, b. continuity from one year to the next ( ), c. shape and timing of ascending during break-up, magnitude of peak and shape of recession, d. LW and HW curve revisions, e. BW interpretation during break-up, f. chart interpretation (reversal correction not used), and g. measurements discarded. A revision of some type was made to every year of record from 1965 to 1984 (20 years or 240 months or 240 months or 7305 days). Revisions were made to 5236 days of record, not including the 451 days prior to 1965 which were deleted, involving 190 of the 240 months. Most of the revisions were made to the daily discharges for the winter recession periods from October to May (127 months) The most significant revision was made to the 1972 data because of an incorrect chart interpretation (reversal not used) the timing and magnitude of the peak were revised. The maximum daily discharge, which had been the minimum maximum for 1965 to 1984, was revised by +95% from 2310 on July 21 to 4500 E m/s on July 6. The mean discharge for July was revised by +118% from 1200 to 2610 m/s and the mean for the year by +44% from 281 to 403 m/s. Other significant revisions were : 1. The mean discharge for 1965 was revised by -17% from 463 to 386 m/s due mainly to the winter recession revision during may and June and a revision to the shape of the ascending limb during breakup. 2. The minimum daily discharge of 2.89 m/s for 1965 to 1984 was considered unreliable because of the use of a backwater curve. The minimum daily discharge for 1965 to 1984 was revised from 2.89 m/s on June 8, 1966 to 24.0 B m/s on May 13,

291 3. The mean discharge for 1971 was revised by +34% from 324 to 433 m/s. The shape of the ascending, timing and magnitude of flows during break-up was revised. The chart interpretation of the gauge height for September 23 was revised. The shape of the winter recession was revised from an arithmetic to a logarithmic shape. 4. Although the mean discharge for 1973 was revised by only +2% from 502 to 513 m/s, a significant revision was made because of an incorrect chart interpretation (reversal had not been applied) The maximum daily discharge was revised by +46% from 2830 to 4120 B m/s and the mean for June by +18% from 1770 to 2090 m/s. Also, the shape of the winter recession was revised from arithmetic interpolation to logarithmic; the mean discharge for November was revised by -38% from 312 to 195 m/s and for December by -41% from 161 to 94.8 m/s. 5. The mean discharge for 1975 was revised by -19% from 537 to 434 m/s. Revisions were made to show a logarithmic recession during winter periods; the shape and timing during break-up was revised; and a LW curve revision was applied. 6. The winter flows for were revised to show a smooth logarithmic recession; the discharge measurement of 13.0 m/s on February 15, 1982 was discarded because of slush conditions and very low velocities. The mean discharge for January was revised by +76% from 28.6 to 50.2 m/s February was revised by +193% from 13.8 to 40.5 m/s March was revised by +185% from 12.4 to 35.3 m/s April was revised by +63% from 19.7 to 32.2 m/s May was revised by -28% from 42.0 to 30.3 m/s However, after all the revisions had been made, the mean annual discharge for 1965 to 1984 was revised by only - 1.5% from 470 to 463 m/s. The comparison hydrographs were provided by Ottawa. Revisions to the data files were submitted to Ottawa who then provided plots and listings incorporating these revisions. Ottawa has created a temporary FLOW file which will be used to update the master file after final approval by Yellowknife and Ottawa. HYDEX updates should be submitted by Yellowknife after their approval.. Historical listings of daily discharges will be sent automatically to Yellowknife by Ottawa for those years for which a revision had been made. The symbol E (estimated) was added to discharges above 15 m/s on the FLOW (14 days) and PEAKS files (6 values). Missing daily discharges for June 19 to July , June 9 to September , June 11 to July and August 7 to September 26, 1984 were estimated to give a complete block of records from July 23, 1973 to date. 40

292 One keypunching error was corrected (December 18, 1974). Winter flows for November 13, 1975 to April 30, 1976 and October 9 to December 31, 1976 were revised to show a smooth logarithmic recession and flows for May 1 to June 8, 1976 were revised because of a different shift correction distribution. A revision (or extension) of some type was made to 5 of the 12 years of record from 1973 to Revisions were made to 498 days of record. The mean discharge for the period of record for 1974 to 1985 was revised by -5% from 2.61 to 2.49 m/s, mainly due to the extension of records for 4 years. 1.3 Birch River at Highway No. 7, Station No. 10ED003 Period of Record Reviewed : 1974 to 1985 The missing daily discharges for June 17 to August 13, 1976 were estimated to complete the records for the year and for the period of record (58 days were estimated). It is unlikely that the flow was nil during winter periods. No flow was published in 1975, 1976, 1977, 1980, 1982, 1983 and However, there was some water under the ice (only about 1 ft thick) and a water level was obtained for all measurements during winter except for those in 1984 where a note states : no water found. Therefore, daily discharges were revised from zero to show some flow for all years except 1984 (the 0 flow as published for January 1 to April 10, 1984 was not revised but should be used with discretion) 198 days were revised. The mean annual discharge for the period of record from 1975 to 1985 was revised by +6% from 1.92 to 2.03 m/s. 1.4 Prairie Creek at Cadillac Mine, Station No. 10EC002 The stagedischarge relation is very unstable, especially at high water. Therefore, the symbol E was added to all daily and maximum instantaneous discharges above 40 m/s; over 20 such days were identified from 1975 to 1985 (see PEAKS and FLOW file updates). Also, the following note was added under Remarks for the next Flows above 40 m/s were estimated and should be used with discretion (see HYDEX file update). Historical Streamflow Summary publication : When the 1975 and 1976 data were revised by the Calgary office in 1980, the PEAKS file inadvertently was not updated, and resulted in the publication of the incorrect value of 281 m/s as the maximum instantaneous discharge for 1976 instead of 81.3 m/s. 41

293 The missing daily discharges for June 1977 were estimated to complete the records for the year and for the period of record from The mean annual discharge for the period of record was revised by +4% from 5.08 to 5.28 m/s. 2. TABULAR PAGES (FORM ) 2.1 Birch River at Highway No. 7 Figure 23: Summary of Revisions 42

294 2.2 Flat River at Cantung Camp 43

295 2.3 Little Southwest Miramichi River at Lyttleton Figure 25: Summary of Revisions 44

296 2.4 Prairie Creek at Cadillac Mine Figure 26: Summary of Revisions 45

297 3. MEANS AND EXTREMES 3.1 Root River near the Mouth Figure 27: Means and Extremes 46

298 3.2 Willowlake River below Metahdali Figure 28: Means and Extremes 47

299 APPENDIX K: EXPLANATION OF REVISIONS 1. BACK RIVER ABOVE HERMANN RIVER, STATION NO. 10RC Gauge height records were obtained from July 20 to August 8, 1962; July 19-24, 1963; and September 22 to November 30, Several attempts were made to obtain continuous records but without success due to numerous technical problems. Twelve discharge measurements were obtained from 1960 to 1964, two each year near the gauge during the open water period from July to September; and two from an ice cover, 1/2 mile downstream in 1963 and 10 miles downstream in The measurement made on April 25, 1963 was discarded; it i considered unreliable because of low velocities (mean 0.07 ft/sec) and only 10 verticals were used. By the way, I didn't make the notation on the List of Measurements but I would tend to agree with the unknown author. Daily discharges (mostly bracketted means) were originally computed from July 20, 1962 to April 30, 1963 and July 19, 1963 to December 31, However, daily discharges for October 1, 1963 to September 30, 1964 were not published. These discharges are mostly estimated and are considered unreliable and of littl value as partial records. Therefore, all data now on the FLOW file prior to January 1, 1965 were deleted. The period of record on the HYDEX file was revised to show miscellaneous measurements for and continuous daily discharge records for 1965 to date. 2. BIRCH RIVER AT HIGHWAY NO. 7, STATION NO. 10ED Gauge height records were obtained from January 1 st to April 22 and July 6 to December 31. The chart trace is very unusual from July 6 to December 31 (wide, rapid fluctuation, painting), making it difficult to interpret the mean accurately. This pattern, or a variation of it, continued from July 6, 1977 to July 8, 1980 (4 years). No explanation of these peculiar traces is given but these gauge height records are considered questionable (shaky). Curve No. 9 was used during open water between 8.62 and ft (428 and 2780 m 3 /s). The two measurements made in 1977 plot 2% and -4% off the curve. No shift corrections were applied. However, curve revisions were considered unwarranted. Chart interpretation for the July 6 to September 1 st segment : a. The chart trace should have been extended back from July 7 to about at 1130 on July 6 and digitizing should have started at that point (not 19.49). The setting error would then be ft not ft, b. On September 1 st, a note on the chart states line found loose from orifice but still under water caught between rocks near end. Gauge height = 9.90 ft Using the chart trace prior to September 1 st as guide (extension), the pen was probably closer to not ft. This would then give a net correction of ft at 1320 on September 1 st (-0.10 setting correction applicable from July 6 to September 1 st and a straight-line pen correction from OK on July 6 to on September 1 st, unless changed abruptly because of the loose line possibly July 16 or 17 when the shape of the recession changes), and 48

300 c. After all this, the mean discharges for July and August could be changed by less than 4%, therefore no revisions were made. However, this exercise was considered worthwhile because the instrumentation and computation problems are documented. Summary of Gauge Height Records 1975 : May 2 to June 1; July 15 to September 17; October 10 to November : April 16 19; April 27 to June 17; August 13 to November : April 23 24, April 26 to December : May 5 to October : May 1 to August 15; August 30 to October : April 19 to October : May 1 to September 17; October : March 30 to April 4; April 9 to December : January 1 to April 16; April 26 to October 14; October 21 to December : April 24 to August 8; August 14 to September 4; October 10 to December : January 9 to December The flows during the ascending limb (April 4 to 16) were revised to show a shape that is more consistent with other stations and other years (see Hydrograph Worksheet) Daily discharges for June 17 to August 13 were estimated to complete the records for the year and also for the period of record for 1975 to Discharge measurements were obtained on June 17 and August 13 and daily discharges for June 18 to August 12 were estimated by hydrograph comparison with the Jean-Marie River. 3. FLAT RIVER AT CANTUNG CAMP, STATION NO. 10EA to 1963 (Location A) Gauge height records were obtained from a manual (chain) gauge for periods of varying length from 1960 to Daily readings were obtained from March 30 to September 30, 1960; from April 29 to August 5, 1961 (some twice daily and some days missing); from April 21 to June 24, 1962 (about twice weekly) and October 1 to 29, 1962 (mostly daily); and occasional readings November, 1962 to July, 1963 (for which daily discharges were not computed). The observer's cards and books are filed with the recorder charts (folder). Large gauge corrections were found (by levels); however, the distribution of daily gauge corrections is questionable. The HQ relation was not defined. Only four open-water measurements were obtained during ; and the shape of base HQ curve and the distribution of the daily shift corrections are questionable. The daily discharge records for were revised by the Calgary Office in 1977 in response to a request (complaint) from a consulting engineering company. 49

301 However, in this review it is considered that inadequate field data were obtained to produce reliable daily discharges another interpretation could be at least 50% different (also see Hydrograph Worksheet and Correspondence). Therefore, the daily discharges for were removed from the FLOW file; and the HYDEX file should show that only miscellaneous discharge measurements are available from 1959 to All original work file data and related correspondence were placed in the Revisions File. Summary of Gauge Height Records for 1973 to : July 23 to December : January 1 to June 18; July 11 to December : January 1 to December : January 30 to June 9; September 14 to December : January 1 to December 7; December : January 1 11; March 1 to July 19; October 3 to December : March 6 to December : January 1 to December : January 1 to February 25; April 1 to December : July 14 to November 6; November 22 to December : January 1 to March 11; April 16 to December : January 1 to August 7; September 27 to December : January 1 to February 3; February 26 to March 14; March 29 to April 8; May 23 to November 8; November Note Water levels were affected by drawdown until the manometer was installed in Stage Discharge Relation from 1973 to 1985 The HQ relation is unstable and is not defined by discharge measurements above 13 m³/s. The control was altered frequently by Cantung personnel by using a bulldozer to maintain a pond for the pumping operation. Three HQ curves were used with shift corrections usually applied on a straight-line basis. The symbol E was added to all flows above 15 m³/s. Natural flows are affected by pumping diversions for use at Cantung Camp (approx. 2 to 3 cfs). 50

302 4. PRAIRIE CREEK AT CADILLAC MINE, STATION NO. 10EC002 Summary of Gauge Height Records 1974 : September 20 to October : May 11 to July 2; July 9 to October : May 17 to 20; June 10 to November : April 28 to May 1; May 16 to June 3; June 28 to December : May 12 to July 4; July 18 to October : June 1 to July 1; July 9 to October : May 15 to November : May 19 to June 7; June 17 to October 31; November 8 to : May 20 to June 12; July 18 to December : April 12 to September : May 21 to June 10; June 14 to November : May 21 to November 6. Note There was significant orifice movement during most high-water periods and some chart interpretations are debatable and 1976 Revisions by the Calgary Office HQ Curve No. 1 was originally used from 1974 to 1976 and was revised by the Calgary Office in 1980, based on a slope-area measurement of 187 m³/s on June 3, Revised daily discharges for 1975 and 1976 were submitted to Ottawa and monthly and annual means then published in the 1982 and 1984 HSS publications (see Memo to File dated ). The maximum daily discharge for 1975 was revised by -52% from 99.1 to 47.5 m³/s and for 1976 by -58% from 127 to 52.8 m³/s. However, the PEAKS file had not been updated, therefore, the 1975 value was not published and the original maximum instantaneous discharge of 281 m³/s was published for July 3, 1976 instead of 83.1 m³/s on July 2 (see PEAKS File Updating Form). The symbol A was shown for May 5, 1976 instead of the symbol E since a discharge measurement was obtained on that date. Stage Discharge Relation The HQ relation is unstable and no current-meter measurements were obtained above 25 m³/s (883 cfs). The HW range is defined by a slope-area measurement of 187 m³/s (6600 cfs) on June 3, 1977; it is of debatable accuracy and may not be applicable for subsequent years. HQ Curve No. 2 was used from 1977 to 1985 with shift corrections applied on a linear time basis. The daily shift correction distribution is questionable since the corrections obtained from measurements below 25 m³/s probably do not apply to HW flows above 40 m³/s, for example : 51

303 a. The 1979 peak as published = m + (0.128 S.C.) 81.6 m³/s and m (with no S.C.) 74.4 m³/s b. The 1983 peak as published = m (0.265 S.C.) 65.3 m³/s and (with no S.C.) = 80.9 m³/s Revisions were considered unwarranted since another interpretation of the S.C. cannot be reasonably substantiated. However, the symbol E was added to all discharges above 40 m³/s and Remarks added for the next HSS publication to warn users about the reliability of HW flows Daily discharges for June 3 to 27 were estimated to complete the records for the year; this was considered warranted since the peak for the period of record from 1975 to 1985 occurred in Estimates were based on a slope-area measurement on June 3 and hydrograph comparison of daily discharges for other stations in the basin (see REVISION WORKSHEET) There is some question regarding the magnitude of the peaks because of the interpretation of the S.C. distribution that was applied. A higher maximum instantaneous gauge height (2.795 m) occurred on August 3 than on June 1 (2.740 m) but because of the difference in S.C. ( on June 1 and on August 3) the June 1 discharge of 22.4 m³/s was published as the maximum instantaneous and the August 3 discharge of 22.4 m³/s as the maximum daily (a listing of the daily shift correction distribution was not obtained from the SAVE file). No revisions were made. The March 10 measurement of m³/s is published as the minimum daily discharge for the period of record from 1975 to This measurement is probably too low because of the very low velocities, mostly estimated. The next lowest measurement of m³/s on April 25, 1985 is not much more reliable. However, no revisions were made but a more reliable measurement section should be selected in future years A comparison with South Nahanni River above Clausen Creek implies that higher flows could have occurred from June 13 to 20 but no revisions were made because they cannot be reasonably substantiated; and probably not worthwhile considering the relative accuracy of HW flows in other years. 5. UPSALQUITCH RIVER AT UPSALQUITCH STATION, NO. 01BE001 Period of Record Reviewed September 1918 to June 1933 and August 1943 to December Revisions 1920 : The daily discharges for the period February 1 to March 3 inclusive were revised according to the original computations. 1920, 1922 and 1933 Discharge records are considered to be estimated above 14,000 cfs due to lack of high water measurements for curve definition. Therefore the symbol E has been added to the FLOW file for the following days : October 02, 1920 June 22, 23, 1922 May 3, 4,

304 1932 : The daily discharges for the period January 1 to 15 inclusive were revised to agree with the original computations : The daily discharges for the period May 8 to 31 inclusive have been revised using the composite stage discharge curve number : The daily discharge for June 8 was incorrectly computed as 1960 cfs and should have been 1,930 cfs. The daily discharge for June 9 was incorrectly computed as 21,150 cfs and should have been 1,720 cfs. The daily discharges for the periods April 21 to May 16, November 28 to December 2, December 5 and December 11 to 15 have been revised using the composite stage discharge curve number : The period April 7 to May 3 was revised using the composite stage discharge curve number : The periods of April 21 to May 28, June 3 and 4, and June 7 to 12 have been revised using the composite stage discharge curve number

305 APPENDIX L: WORK SHEETS BACK RIVER ABOVE HERMANN RIVER Figure 30: Prevision Worksheet Figure 29: Revision Worksheet 54

306 APPENDIX M: REVISIONS 1. DAILY DATA FILES UPDATING 1.1 Birch River at Fort Liard Highway Figure 31: Daily Data Files Updating 1.2 Tetagouche River Figure 32: Daily Data Files Updating 55

307 2. PEAKS FILE UPDATING 2.1 MacCreek near the Mouth Figure 33: Peaks File Updating 3. HYDEX FILE UPDATING (GAUGING STATION INVENTORY) 3.1 Back River above Hermann River Figure 34: Gauging Station Inventory 56

308 3.2 10NC001 Figure 35: Gauging Station Inventory Updating 4. STAGE DISCHARGE TABLE REVISION 4.1 Anderson River below Carnwath River Figure 36: Stage Discharge Table 57

309 THE WATER SURVEY OF CANADA HYDROMETRIC TECHNICIAN CAREER DEVELOPMENT PROGRAM Lesson Package No. 24 OVERVIEW: Submitting Data To Headquarters P.O. Anderson Water Survey of Canada Environment Canada Ottawa, Ontario Canada K1A 0H3

310 Copyright All rights reserved. Aussi disponible en français

311 TABLE OF CONTENTS 1.0 PURPOSE AND BACKGROUND OBJECTIVES INTRODUCTION HYDEX AND SEDEX SYSTEMS HYDEX SYSTEM HYDEX File REMARKS File SEDEX SYSTEM SEDEX File COMMENTS File UPDATE SCHEDULES ANNUAL DATA PUBLICATION HYDEX Publication HYDEX File Publication REMARKS File Publication HYDEX Retrieval and Update DISCHARGE WATER LEVELS FILE VALID EXTREME CODES ANNUAL PEAKS CONCENTRATIONS INSTANTANEOUS FILE HISTORICAL DATA FLOW FILE WATER LEVELS FILE EXTREME CODES PEAKS UPDATE SCHEDULE REFERENCES...18 iii

312 1.0 PURPOSE AND BACKGROUND This lesson package is to be presented to Hydrometric Survey Technicians as part of the Hydrometric Survey Technician Career Development Program. The collection, compilation and computation of water level, discharge and sediment data are the responsibility of the eight regional offices and their suboffices. Once the computations of the data have been completed and finalized, the data have to be submitted to Ottawa for storage and publication. This lesson package will focus on the methods used and the files required for the publication of the annual and historical data and for the permanent storage of these records in the National Hydrometric Data Bank (HYDAT). 2.0 OBJECTIVES The objective of this lesson package is to supply the participants with background information related to the submission of data to headquarters. Information about the required deadlines for the transmittal of data and file structures will be provided. 3.0 INTRODUCTION The Water Resources Branch HYDAT database is frequently accessed by various agencies, within and outside of Government, for hydrometric data. These data are used for many purposes and it is important that the files contain up-to-date information for the user to access. Once the updated or revised data are verified in the Region, this package will provide the necessary instructions to transmit the data to Ottawa for updating. 1

313 4.0 HYDEX AND SEDEX SYSTEMS 4.1 HYDEX SYSTEM The purpose of the HYDEX system is as follows : 1. Provide management statistics, e.g., number and/or name of active streamflow stations in Alberta, cableways in Manitoba, sediment stations in Canada and the number of active streamflow and water level stations in Canada by province or by Region. 2. Provide printouts showing gauging stations in the various categories which are included in cost-sharing agreements with the provinces. 3. Produce computer listings suitable for publishing the biennial Surface Water Data Reference Index for Canada. 4. Produce computer listings suitable for distribution to users or for the annual Surface Water Data publication and the Historical Streamflow/Water Levels Summary publication (published every 2 years) HYDEX File The HYDEX file contains an inventory of the latest conditions at all active and discontinued gauging stations; it is presently stored on a magnetic file in Ottawa. The Gauging Station Inventory listing is a one-station-per-page printout from this file; a copy of the listing is retained both in the regional office and in Ottawa. This section explains how Regions can keep these listings up-to-date by submitting revised listings to Ottawa or by completing a Gauging Station Inventory Updating form for new stations. Gauging Station Inventory listings with revised information (or Gauging Station Inventory Updating form for new stations) are submitted by the regional offices and the new or revised information is coded and keypunched in Ottawa for subsequent storage in the HYDEX system. The HYDEX system is updated in Ottawa on a monthly basis. Upon completion, the following items are sent to the appropriate regional office : 1. Gauging Station Inventory listings for updated stations. 2. HYDEX verification listing of updates. 3. All updating forms, letters, etc., for updating the file. 4. A reduced copy of the Summary of Active Gauging Stations in Operation as of (date). 5. Other retrievals if requested REMARKS File The REMARKS file consists of variable-length records of up to 510 characters. This is a high activity file and is updated at least once a month. The REMARKS file is primarily used to store narrative information for a station. The following fields for the Gauging Station Inventory listing are retrieved from REMARKS. 09 Location 10 Tributary to 72 Remarks for Annual SWD Publication 73 Remarks for Historical Streamflow Summary Publication 74 Remarks for Historical Water Levels Summary Publication 75 General Remarks. 2

314 Updates to these fields are handled exactly like the HYDEX updates; the field is identified and the revision is clearly marked. 4.2 SEDEX SYSTEM The purpose of the SEDEX system is as follows : 1. Provide management statistics, total number of active sediment stations, number of automatic samplers currently in use, number of stations providing Tonnes data or Particle Size data during the period of record by province or by Region. 2. Produce computer listings suitable for publishing the biennial Sediment Data Reference Index for Canada. 3. Produce computer listings suitable for distribution to users, or for the annual Sediment Data Publication and the Historical Sediment Data Summary publication (every 5 years) SEDEX File The SEDEX file contains an inventory of the latest condition at all active and discontinued sediment stations; it is presently stored on a magnetic file in Ottawa. The Sediment Station Inventory listing is a one-station-per-page printout from this file; a copy of this listing is retained both in the regional office and in Ottawa. The Regions are to keep these listings up-to-date by submitting revised listings to Ottawa or by completing a Sediment Station Inventory form for new stations only. The SEDEX system is updated in Ottawa on a monthly basis. Upon completion, the following are sent to the appropriate regional office : 1. Sediment Station Inventory listing for updated stations. 2. All updating forms, letters, etc., for updating the file. 3. Other retrievals if requested COMMENTS File The COMMENTS file consists of variable-length records of up to 510 characters. This is a high activity file and is updated in Ottawa via an interactive terminal prior to the publication of the suspended-sediment data. The records are stored by station number order, with the field number as the secondary key. These comment records do not go through an EDIT program for verification. A listing is produced, however, and a visual check of all comments is necessary before records are ready to be inputted into the update program. Updates to this field are handled exactly like SEDEX updates. 4.3 UPDATE SCHEDULES The HYDEX and SEDEX systems are updated in Ottawa on a monthly basis. 3

315 5.0 ANNUAL DATA The present system of publishing annual surface water data requires that four separate files be maintained containing only the data for the year being published. These four files are : 1. Publication HYDEX 2. FLOW 3. LEVELS 4. PEAKS. The most obvious reason for creating these files with only the current year's data is the requirement to save processing time, especially in updating the FLOW and LEVELS files. Another not so obvious reason for maintaining a separate HYDEX file is that the master HYDEX file reflects the current status of all gauging stations whereas the publication HYDEX refers to the year during which data were collected. 5.1 PUBLICATION HYDEX The publication HYDEX consists of two files : 1. Publication HYDEX 2. Publication REMARKS Publication HYDEX File The publication HYDEX is created with a special program that extracts (from the master HYDEX) the code records containing datum names, contributing agency names and all records for active stations except those with a current type of record as M (miscellaneous). The program is designed to produce a list of all stations extracted which will indicate whether each station is a FLOW or LEVELS station. The publication HYDEX file contains only those stations which are to be published in the publication year being processed. Moreover, this file contains only the information necessary for publication : station number station name region code international designation drainage area co-ordinates (latitude and longitude) province code type of record type of gauge current and other datum code with conversion factor (water level stations only) standard period (discharge stations only) type of flow and year of regulation contributing agency code 4

316 remarks for annual Surface Water Data publication. The publication HYDEX file is usually created at the end of the year, before the master HYDEX file is updated to show the on-coming year in the period of record for all active stations Publication REMARKS File The term HYDEX file is a general term which is commonly used to refer to two separate files used internally in Ottawa, namely the HYDEX file and the REMARKS file. These two files contain all the information shown on the Gauging Station Inventory listing. Just as a publication HYDEX file is created from the master HYDEX file, a publication REMARKS file is created from the master REMARKS file. The publication REMARKS file contains the remarks for the annual Surface Water Data publication for those stations which are to be published in the current publication. This file is created using the FORM utility and the remarks are stored on disk and updated as required for the publication Publication HYDEX Retrieval and Update The publication HYDEX listing is obtained as soon as the publication HYDEX file is created. The publication HYDEX listing contains a dump of all gauging station information stored on the publication HYDEX file. Retrieval is always requested by Region. Initially, all Regions are retrieved, but for subsequent retrievals, only the Regions for which data were updated need be retrieved. This HYDEX retrieval listing is a work listing which can also be used as a checklist to ensure that all data for each station have been submitted. Three columns are provided on the right side of the listing for indicating if PEAKS are available, if there is a valid extreme code, and if data for the year or standard period are complete or partial. Figure 1: Sample of Publication HYDEX Listing 5

317 Updates to the publication HYDEX should be made on the printout using a method that will indicate distinctly any changes that are required; Hi-liters or red pens work well. Once a field has been identified for a revision, the change should be written on the listing. It should be noted that in some cases there is a requirement to publish both FLOW and LEVELS for a station. If this should occur, it is necessary to change the type of record (Q or H) to a Z. The program will recognize this letter and will expect to find records on both the FLOW file and LEVELS file. If at the time the publication HYDEX was created, a station was not on the master HYDEX but data were available for publication or if changes were made to the master HYDEX after the creation, these stations or changes will not appear on the publication HYDEX. These changes will have to be indicated on the publication HYDEX listing. It is important to remember that only the stations and information regarding these stations that appear on the publication HYDEX listing will be published in the annual Surface Water Data Publication listing. Note If the changes being made to the publication HYDEX are required on the master HYDEX, a separate update must be supplied to Ottawa. It is also important to check the REMARKS for publication carefully. These remarks should identify conditions which affect the data being published. If, for example, there was a beaver dam that affected the flows during the previous year, this remark may not be relevant to this year's data. Also, only 120 characters may be used to describe any unusual conditions in remarks for publication. 5.2 DISCHARGE When the STREAM program is executed for a hydrometric station on the computer systems in each Region, files are created containing only water levels or both water levels and discharges. For a station designated as a FLOW station, a file QQXX.STR is created. Once all the FLOW stations for a Region are complete, the Data Control Engineer/Head will assemble all the QQ files into one and name the file QQXX.YYY, where XX is the year and YYY represents the first three letters of the Region; e.g., QQ87.VAN indicates Vancouver 1987 discharge data. At this point there are two choices : 1. either the Region sends the data to Ottawa via DecNET or 2. the Region calls the Data Control Section in Ottawa and has them retrieve the data. In either case the data are stored on an account DU1: [PUB]. The annual FLOW file is updated with the data retrieved, and two listings, provisional and publication, are retrieved and returned to the Region for checking. The Provisional Listing produces a listing of the daily discharge data and the symbols, one station year per page. For each month of data, complete or partial, the monthly total in m³/s days is computed. For complete months, the monthly mean in m³/s, the total discharge in dam³ and the maximum and minimum daily discharges are also computed. The daily discharges on this page are not rounded, but are printed exactly as they appear on the file. The Provisional Listing is the only listing which provides monthly totals for easier verification of the data by regional staff. The Publication Listing program reads the FLOW, HYDEX, REMARKS and PEAKS files and produces listings of 6

318 the daily discharges with one calendar year per page as shown in the examples to follow. This listing is used as a final check of the annual publications. It is sent to the appropriate regional office for verification prior to publication and a copy is filed with the Data Control Section in Ottawa. The station name is read from the HYDEX file. The daily discharges are read from the FLOW file, rounded and then lined up for printing on the page. For complete months, a monthly summary is prepared with the total discharge in m³/s days, the mean discharge in m³/s, the total discharge in dam³, and the maximum and minimum daily discharges. For a complete year or standard period, an annual mean is printed. The extremes for the year are printed, if valid. Also, if symbols such as A, B or E have appeared on this page, then a key is printed in the bottom center which gives the meanings of these symbols. Descriptive information is also extracted from HYDEX including the type of gauge, location, drainage area, data contributed by, international designator and regulated or natural flow. The maximum instantaneous discharge, if available for this year, is read from PEAKS and printed with its time and date of first occurrence. Textual information, if available for this station, is read from the REMARKS file and printed at the bottom of the page. Figure 2: Sample of Provisional FLOW Listing 7

319 Figure 3: Sample of Publication FLOW Listing There are two versions of this program : I. an English version used to retrieve all listings except Quebec listings, and II. a French version used to retrieve only Quebec listings. If, during checking, corrections or revisions are required, the following procedure must be followed. A file will be created on the computer system which will contain any corrections or revisions to the annual data. The file will be created in the following format. The following symbols are valid when updating the FLOW file (all other symbols will be ignored) : A manual gauge B ice conditions E estimated R to indicate revised data N for deletion of symbol only X for deletion of both value and symbol * for deletion of revision code. All of the above symbols may appear alone in the data field followed by a plus (+) sign. Numeric values in the data field may be entered alone or with the symbols A, B or E. Changes to the daily symbol field only will not be considered a revision. 8

320 5.3 WATER LEVELS FILE Each time the STREAM program is run on the computer system, a file is created for water levels. This file is identified as WLXX.STR. It is updated with the computed values even if the station is classified as a discharge station. When all the LEVELS stations are complete, the Data Control Engineer/Head will assemble only the water levels for stations to be published as water levels only. These files, when combined, are named WLXX.YYY, where XX is the computational year and YYY represents the first three letters of the Region : e.g., WL87.WIN indicates Winnipeg 1987 water level data. At this point, the decision is made either to send the file to Ottawa or to have the file retrieved. Again the data is stored on the account DU1: [PUB]. The annual LEVELS file is updated with the data received, and two listings, provisional and publication, are retrieved and returned to the Region for checking. The Provisional Listing produces listings of the daily water level data and the symbols for checking. They are also the only listings which display monthly totals for easier verification of data by the regional staff. The monthly total in metre days is computed for each month of data, complete or partial. For complete months, the monthly mean in metres and the maximum and minimum daily water levels are also computed. A datum code line is printed for each station which shows the datum code stored for each month. This line is followed by a revision line which indicates if any of the daily values in a month are revised by printing REV under the appropriate month. If daily data are missing but a symbol is present on the LEVELS file, then only the symbol will be printed. The symbols A, D, E, N, *, R and X are the only valid symbols. The Publication Listing program reads the LEVELS, HYDEX, REMARKS and PEAKS files and produces listings of the daily water levels with one calendar year per page as shown in the examples which follow. This listing is used as a final check of the annual publications. It is sent to the appropriate regional office for verification prior to publication and a copy is filed with the Data Control Section in Ottawa. The station name is read from the HYDEX file. The daily water level and corresponding symbol are read from the LEVELS file and printed. If the symbol D is encountered, the word DRY is printed as the water level value. The monthly mean maximum and minimum water levels are shown only for the complete months. The mean for the year is only printed if the calendar year is complete. The extremes for the year are printed, if valid. Also if symbols such as A or E have appeared on the printout, a key is printed in the lower right-hand corner which gives the meanings of these symbols. 9

321 Figure 4: Sample of Provisional LEVELS Listing Figure 5: Sample of Publication LEVEL Listing 10

322 Descriptive information is also extracted from HYDEX including the type of gauge, location, drainage area, data contributed by, international designator, and regulated or natural flow. The maximum instantaneous water level and corresponding symbol, if available, is read from PEAKS and printed with its time and date of first occurrence. Textual information, if available for this station, is read from the REMARKS file and printed at the bottom of the page. There are two versions of this program : I. an English version used to retrieve all listings except Quebec listings, and II. a French version used to retrieve all Quebec listings only. If corrections or revisions have to be made to previously submitted data, after the annual data have been verified, a file will be created on the computer system which will contain only corrections or revisions to the annual data. The file created will be in the following format. The following symbols are valid when updating the LEVELS file (all other symbols will be ignored) : A manual gauge E estimated D to indicate a DRY reading R to indicate revised data N for deletion of symbol only X for deletion of both value and symbol * for deletion of revision code. All of the above symbols may appear alone in the data field followed by a plus (+) sign. Numeric values in the data field may be entered alone or with symbols A or E. Changes to only the daily symbol field will not be considered a revision. An entire month's data may be deleted, revised or revision symbols deleted by entering 00 in columns l6 l7, and X+, R+, *+ in columns 2l 22 respectively. 5.4 VALID EXTREME CODES Under normal circumstances, the maximum and minimum daily discharges or water levels are not extracted for stations with incomplete records for the year or, in the case of discharges, incomplete standard periods. In many cases, both the maximum and minimum may be valid. Also, in some cases, where only monthly means are supplied, neither maximum nor minimum are valid. If there are extremes that should or should not be published, a code can be entered on the FLOW or LEVELS files which will permit the values to be extracted or ignored. The following are the codes used for identification of valid daily extremes for the year or standard period. B both maximum and minimum are valid H maximum only is valid L minimum only is valid X delete any previously entered code. For stations which may have a complete period but neither extreme is valid, the following code applies : N neither maximum nor minimum is valid. 11

323 Valid extreme codes are keypunched in the following format. A file will be created on the computer for transmission to Ottawa in the above format. It is imperative that this file be created in station number order. If it is not in station number order, the update will not work. 5.5 ANNUAL PEAKS The annual PEAKS file contains information on maximum instantaneous values for both streamflow and water level stations. When available, the following data are stored on this file : maximum instantaneous value (including symbol if required) month of first occurrence day of first occurrence time and time zone of first occurrence current datum code (required only for water level data). This information is printed as part of the summary for the year or standard period on the data pages. A separate historical PEAKS file does exist, but for the same reasons that separate publication FLOW and LEVELS files are created, a publication PEAKS file is maintained containing only the maximum instantaneous data for the year being published. A file will be created on the computer for transmission to Ottawa. This file may be created in any order (it does not have to be in station number order) in the following format. Columns l l6 must be keypunched in all cases, except for columns l0 l2 which are used for water level data only. When entering a value on the PEAKS file, all the related information (columns l8 29 or a symbol) must also be keypunched. When revising or changing related information already on the file, however, only that field being changed has to be keypunched; e.g., if the time is being changed from l4:23 to l4:33 and the symbol B is to be deleted, keypunch data for columns l l6 and enter 33 in columns and N in column 30. Symbols that may be used in the value field are as follows : A manual gauge B ice conditions E estimated R to indicate revised data X for deletion of the value and symbol N for deletion of the symbol only * for deletion of a revision code. Any of the above symbols may appear alone in column 30 of the value field but only symbols A, B, or E may be entered with the value and must immediately follow the value. 5.6 CONCENTRATIONS When the SEDCON program is executed for a sediment station on the computer systems in each Region, a file is created containing the suspended-sediment concentrations. Once all the sediment stations for a Region are 12

324 complete, the Data Control Engineer/Head will either send the data to Ottawa via DecNET or call the Data Control Section in Ottawa and have them retrieve the data. The SUSCON file is updated with this latest data, and provisional listings are retrieved and returned to the Region for checking. Figure 6: Sample of Provisional SUSCON Listing 5.7 INSTANTANEOUS FILE An instantaneous suspended-sediment file for a sediment station is created on the computer systems in each Region using routine. The data are entered using the instantaneous suspended-sediment data form. Once the instantaneous file is updated, a file is created containing water temperatures, instantaneous discharge, sampling vertical, type of sampler, instantaneous concentrations and the dissolved solids. When all the sediment stations for a Region are complete, the Data Control Engineer/Head will either send the data to Ottawa via DecNET or call the Data Control Section in Ottawa and have them retrieve the data. The INSTANT file is updated and provisional listings are retrieved and returned to the Region for checking. 13

325 Figure 7: Sample of Provisional INSTANT Listing 14

326 6.0 HISTORICAL DATA The historical FLOW and LEVELS files are updated at least annually after the annual daily data for a publication year have been verified and submitted for printing. Any corrections or revisions to previous data are also included in the updating at this time; these are verified the same way as the annual data. 6.1 FLOW FILE All revisions, changes or additions made to the daily values on the master data files, except data for the current year until it is published, will be identified by the symbol R following the value. However, to conserve space, the symbols S, T and W are used in combination with an A Manual Gauge, B Ice Condition or E Estimated to indicate revisions for those days. Changes to only the daily symbol field will not be considered a revision. Both current data and historical corrections are keypunched in the following format. The following symbols are valid when updating the FLOW file (all other symbols will be ignored) : A manual gauge B ice conditions E estimated R to indicate revised data N for deletion of symbol only X for deletion of both value and symbol * for deletion of revision code. All of these symbols may appear alone in the data field followed by a plus (+) sign. Numeric values in the data field may be entered alone or with symbols A, B or E. Changes to only the daily symbol field will not be considered a revision. An entire month of data may be deleted by entering 00 in columns Revisions to data are performed by entering the X+ symbol in columns The R+ symbol is entered in column to indicate that data has been revised while the *+ symbol in the same columns is entered to delete the revision code. All revisions for the FLOW file are to be entered on a computer file using the above format. Once entered and complete, the file will be transferred to Ottawa where the historical FLOW file will be updated. Listings are returned to the Region for verification. 6.2 WATER LEVELS FILE All revisions, changes or additions made to the daily values on the master data files will be identified by the symbol R following the value. However, to conserve space, the symbols S, W and V are used in combination with an A Manual Gauge, E Estimated, D Dry to indicate revisions for those days. Changes to the daily symbol field only will not be considered a revision. 15

327 Both current data and historical corrections are keypunched in the following format. The following symbols are valid when updating the LEVELS file (all other symbols will be ignored) : A manual gauge E estimated D to indicate a DRY reading R to indicate revised data N for deletion of symbol only X for deletion of both value and symbol * for deletion of revision code. All of the above symbols may appear alone in the data field followed by a plus (+) sign. Numeric values in the data field may be entered alone or with symbols A or E. Changes to only the daily symbol field will not be considered a revision. An entire month of data may be deleted by entering 00 in columns Revisions to data are performed by entering the X+ symbol in columns The R+ symbol is entered in column to indicate that data has been revised while the *+ symbol in the same columns is entered to delete the revision code. All revisions for the LEVELS file are to be entered on a computer file using the above format. Once entered and complete, the file will be transferred to Ottawa where the historical LEVELS file will be updated. Listings are returned to the Region later for verification. 6.3 EXTREME CODES Under normal circumstances, the maximum and minimum daily discharges or water levels are not extracted for stations with incomplete records for the year or, in the case of discharges, incomplete standard periods. In many cases, both the maximum and minimum daily discharges are valid. If both values are not valid, either the maximum or the minimum value may be valid. In some cases, where only monthly means are supplied, neither maximum nor minimum are valid. If there are extremes that should or should not be published, a code can be entered on the FLOW or LEVELS files which will permit the values to be extracted or ignored. The following codes are used to identify the valid daily extremes for the year or standard period. B both maximum and minimum are valid H maximum only is valid L minimum only is valid X delete any previously entered code. For stations which may have a complete period, but neither extreme is valid, the following code applies : N neither maximum nor minimum is valid. 16

328 Valid extreme codes are keypunched in the following format. A file will be created on the computer for transmission to Ottawa in the above format. It is imperative that this file be created in station number order. If it is not in station number order the update will not work. 6.4 PEAKS The PEAKS file contains information on maximum instantaneous values for both streamflow and water level stations. When available, the following data are stored on this file : maximum instantaneous value (including symbol if required) month of first occurrence day of first occurrence time and time zone of first occurrence current datum code (required only for water level data). This information is printed as part of the summary for the year or standard period on the data pages. All current and historical additions, changes and revisions of annual maximum instantaneous discharges or water levels are entered in the following format. A file will be created on the computer for transmission to Ottawa in the above format. Updated listings will be returned to the Region for verificaton. Columns l l6 must be keypunched in all cases, except for columns l0 l2 which are used for water level data only. If the discharge or water level data being keypunched are an addition or a revised value, all fields must be keypunched. If the data are a revision of one or more of the other related fields, then only positions l to 9, l3 to l6 and those fields being revised need be keypunched. Symbols that may be used in the value field of the input card for the EDIT program are as follows : A manual gauge B ice conditions E estimated R to indicate revised data X for deletion of the value and symbol N for deletion of the symbol only * for deletion of a revision code. Any of the above symbols may appear alone in column 30 of the value field, but only symbols A, B, or E may be entered with the value and must immediately follow the value. 6.5 UPDATE SCHEDULE The historical data files are updated annually, usually in February prior to the annual data arriving in Ottawa. 17

329 7.0 REFERENCES Environment Canada (1980), HYDEX Systems Operations Manual, Inland Waters Directorate, Ottawa, pp. 85. Environment Canada (1983), SEDEX System Operations Manual, IWD, Ottawa, pp. 55. Environment Canada (1983), FLOW File Operations Manual, IWD, Ottawa. Environment Canada (1981), LEVELS File Operations Manual, IWD, Ottawa. Environment Canada (1981), PEAKS File Operations Manual, IWD, Ottawa, pp. 20. Environment Canada (1981), Publication Procedures for Surface Water Data, 2 nd Edition, IWD, Ottawa, pp. 32. Environment Canada (1981), Publication Procedures for the Historical Streamflow Summary, 1 st Edition, IWD, Ottawa, pp. 39. Environment Canada (1981), Publication Procedures for the Historical Water Levels Summary, 1 st Edition, IWD, Ottawa, pp. 39. Environment Canada (1981), Publication Procedures for the Surface Water Data Reference Index, 2 nd Edition, IWD, Ottawa, pp

330 THE WATER SURVEY OF CANADA HYDROMETRIC TECHNICIAN CAREER DEVELOPMENT PROGRAM Lesson Package No. 25 Supplying Data To Users (Instructor's Booklet) D. Kirk Water Survey of Canada Environment Canada Ottawa, Ontario Canada K1A 0H3

331 Copyright All rights reserved. Aussi disponible en français

332 TABLE OF CONTENTS 1.0 PURPOSE AVAILABLE WATER RESOURCES BRANCH DATA DATA MEASURED AND COLLECTED DATA COMPUTED BASIC DATA STORAGE NATIONAL HYDROMETRIC DATA BANK (HYDAT) USERS' REQUESTS IMPORTANCE OF DATA REQUESTS USER COSTS FOR DATA BILINGUAL RESPONSE TO REQUESTS SUPPLYING HISTORICAL DATA TO USERS DATA PUBLICATIONS History of Data Publications Data Publications Available Distribution of Data Publications Water Resources Branch Mailing List MICROFICHE MAGNETIC TAPE FLOPPY DISK INTERACTIVE USER RETRIEVALS HYDROGRAPHS STATISTICAL PLOTS HOURLY DATA STAGE DISCHARGE TABLES RECORDER CHARTS METER NOTES SUPPLYING CURRENT DATA TO USERS PROVISIONAL DATA STANDING REQUESTS HOURLY REQUESTS REAL-TIME DATA OTHER CURRENT DATA SEDIMENT DATA SUPPLYING OTHER DATA TO USERS GENERAL PUBLICATIONS Reference Indices Surface Water Data Reference Index Map Supplement HYDEX SEDEX Retrievals iii

333 6.1.4 Manuals Study Reports Regional Data Publications STATION DESCRIPTIONS BENCHMARK ELEVATIONS GENERAL INFORMATION Pamphlets WATDOC Inland Waters Directorate Publications Provincial Publications REPORTING PROCEDURES SUMMARY MANUALS AND REFERENCES MANUALS REFERENCES APPENDIX A: SAMPLES OF INTRODUCTORY TEXT TO PUBLICATIONS...23 APPENDIX B: SAMPLES OF DATA PUBLICATIONS...24 APPENDIX C: QUESTIONNAIRE AND REPLY CARD...25 APPENDIX D: PLOT REQUEST FORM...27 APPENDIX E: PUBLICATION PROCEDURE FOR SURFACE WATER DATA REFERENCE INDEX..28 APPENDIX F: HYDROMETRIC MAP SUPPLEMENT...29 iv

334 1.0 PURPOSE This training package is to be presented to technicians at the EG-ESS-4 level to make them aware of the various types of data supplied to users. It is assumed that the technician is familiar with the data collection procedure and has had some experience with data computation. This manual will provide insight as to how users obtain various data, from whom, and on what media. For reporting purposes, each data request is categorized as one of three types of data : i. historical data, ii. iii. current data, or other data. The lesson will cover data dissemination in Sections 4, 5 and 6, using the same categories. The main emphasis of this training package will be the major data sources available, with little or no mention of the exceptional situations, such as water level slope from a two-gauge station. 1

335 2.0 AVAILABLE WATER RESOURCES BRANCH DATA 2.1 DATA MEASURED AND COLLECTED The Water Survey of Canada (WSC) has the federal mandate for the collection of hydrometric and sediment data across Canada. Data are collected at specific sites on rivers and lakes where gauging stations have been established. A gauging station generally consists of a gauge shelter containing a water level gauge for measuring the surface level of the river or lake. (Manual gauges are usually not placed in gauge shelters.) Water levels are recorded on analogue charts. Technicians pick up the charts and bring them back to their office. Some sites are equipped for transferring data to the office electronically (e.g. via telemark, data collection platform). In addition to recording water level information, some sites are equipped for the automatic recording (and transmittal) of other data such as : water temperature, ground-water elevations, suspended sediment samples, meteorological information, river velocities, and equipment operation information. Gauging stations are visited regularly by technicians to service the equipment and to perform surveys for collecting additional information, usually discharge measurements and suspended sediment sampling. In the performance of these measurements, data such as : river width, river profile, river cross section, water velocity, water temperature, air temperature, ice thickness and other river channel conditions are recorded. All the data collected at the station are transported to the regional and sub-offices of the Water Survey of Canada and stored in current or historical files. Some of the data are retrieved from certain sites by electronic means (telephone or satellite) and stored. 2.2 DATA COMPUTED Approximately 25% of the gauge sites are operated by the WSC for the collection of water level data only. The water level trace on the analogue chart is converted to digital data using a digitizer in the sub-office or regional office. The digital data are then stored on disk on the WRB computer system. Adjustments to these values are made where necessary using a computation program (STREAM), and daily water levels are computed and retrieved on printouts and a temporary disk file. About 75% of the stations have been established to collect discharge data. Discharge measurements are used to determine a stage discharge relationship at the site. A curve is drawn by hand, and points are selected from the curve to create a stage discharge table, which is then keyed into a computer file. The computer program STREAM is used to calculate daily mean discharges by using the digitized points from the water level charts, the stage discharge table and other adjustment tables used to correct for vertical movement of the gauge and changes to the hydraulic characteristics of the river channel. These computer files are stored on-line during the current year. Following the annual publication of the discharge data, the files are stored off-line on a disk or computer tape. These archived data are known as the SAVE file. At some water level sites, particularly in Western Canada, a stage contents table is used in place of the stage discharge table. It is used to compute reservoir contents. Sediment data are collected at roughly 10% of the gauging stations in Canada, the majority being samples of suspended sediment taken at discharge stations. A program of sampling bed-material and bed load is also done at 2

336 selected sites. In addition, special projects such as reservoir sedimentation studies and morphological studies are conducted on an intermittent basis across the country. The sediment samples are sent to one of the four laboratories operated by the Water Survey of Canada (New Westminster, Regina, Guelph, and Moncton) where they are analyzed for total concentration, dissolved solids and, in some cases, particle size distribution. The concentrations are plotted on the station's water level charts and an interpreted curve of instantaneous concentrations is drawn. This curve is digitized to produce mean daily concentrations, and when combined with river discharge, sediment load expressed in tonnes per day is computed. These data, however, are only produced for sites where sufficient samples to draw an accurate concentration curve are available. The following types of sediment data are stored in the national data bank (HYDAT) or on regional files in hardcopy, publications, microfiche or computer tape : Daily mean suspended-sediment concentrations in milligrams per litre Sediment load in tonnes per day Water temperature Dissolved solids in milligrams per litre Suspended sediment and bed-material particle size Depth-integrated and point-integrated concentrations Sampling information such as sampler type, time and date of samples and instantaneous concentrations. Data are also provided by contributing agencies to the regional offices. These data, mostly daily water levels and discharges, are supplied on paper and entered onto a disk file. 2.3 BASIC DATA STORAGE Paper files collected in the field or generated during computations are retained in the local office for at least the current year. They are later forwarded to the Regional Office for archiving. Some regions have storage areas for these files; others store the data at their local Public Archives Office. The daily discharge/water level/sediment data and the maximum instantaneous data are forwarded to Ottawa from the regional offices annually. These procedures are covered in Training Package No. 24. The data are updated and stored on the National Hydrometric Data Bank (HYDAT). Upon completion of computations for a year, the electronic computation files are removed from the active disk files and stored on an archival file referred to as a SAVE file. These files are retained off-line in the regional offices but can be mounted and accessed at any time. 2.4 NATIONAL HYDROMETRIC DATA BANK (HYDAT) HYDAT is a computer tape data bank system maintained by the Water Resources Branch, Data Control Section, in Ottawa. Historical data for all of Canada collected by the Water Resources Branch are stored in this bank. The HYDAT system has eight data files : These files are updated on a regular schedule in Ottawa as the historical revisions are supplied, or when the annual data are supplied. The following table indicates the approximate amount of data across Canada stored in the HYDEX, FLOW, LEVELS and SUSCON files. 3

337 3.0 USERS' REQUESTS Users request data for a variety of reasons. They can be cottage owners concerned about high water levels, consulting firm engineers designing a grand diversion scheme, or senior government officials setting international water management policies. For more information on data uses refer to the Uses of Water Resources Data bulletin prepared by P.I. Campbell in Data requests are answered by staff in the sub-offices, regional offices, head offices, and the publication Distribution Office. Requests are defined for reporting purposes (to Ottawa) in the following excerpt from the Data Dissemination Summary report : A request is determined by using the following guide : a. Upon receiving a request by letter, telephone or in person b. Each time data are supplied to a standing request c. A request from other WSC offices (outside their office) d. A request for several types of data would be considered as one request and categorized according to the major data supplied e. All requests that include sediment data will be considered as sediment requests. If other hydrometric data are also requested, this will be considered as two requests (one sediment, one hydrometric). Definitions Data Requests Historical data : Requests for data published before the date of the request, including Historical Streamflow Summary and Surface Water Data publications, microfiche, hourly data, stage-discharge tables, hydrographs, gauge charts and meter notes. Current data : Requests for data not published before the date of the request. Other data : Requests for maps, station descriptions, benchmark elevations, general publications, reference indices, manuals, HYDEX-SEDEX retrievals, and other information. Remarks User Groups Federal government : Canadian federal government agencies, including Crown Corporations. Provincial government : Provincial government agencies, including conservation authorities and hydro companies. Educational institutes : Elementary and secondary schools, colleges, universities and public libraries. Engineering consultants : Engineering consulting firms. Private individuals : All users requesting data as private individuals, e.g., no company title or address. Other agencies : All other users, including law firms, insurance companies, municipal governments, and American or foreign (government and private) users. 3.1 IMPORTANCE OF DATA REQUESTS 4

338 Responding to data requests is a top priority for the Water Resources Branch. Every request should be handled seriously, courteously and responsibly, with the aim to be as helpful as possible. It is also an aim of those working for the Water Resources Branch to promote their product and make the public aware of the availability of data. This is partially being done by pamphlets, data books, maps, presentations at conferences, displays, training at university and ads in journals. As well, the image of the Branch can be enhanced by personal contributions in public and high schools, clubs, and any contact with users or the public. Technicians should be aware that they are at liberty to talk about any technical aspects of their work (e.g., their equipment and how discharge data are collected) to the public including the media. However, questions concerning management policy or opinions should be referred to senior personnel. 3.2 USER COSTS FOR DATA At present, there is no official Branch policy for the recovery of funds for supplying data. A guideline policy is being developed for the Department, which will be used when a Branch policy is established. Most data are currently provided free of charge, with the following exceptions : i. Headquarters asks users to supply their own magnetic tape when requesting data. ii. Some regions, for large requests of original data, will send the material to a commercial printer for photocopying and will have the bill sent to the requesting agency. iii. Some regions have a costing procedure for their computer requests and send bills to the user. iv. Users who retrieve data from the HYDAT system in Ottawa using the IPAR procedure have their own account on the Computer Services Centre and are billed directly for computer time. 3.3 BILINGUAL RESPONSE TO REQUESTS The following quote is from the Policy on Bilingualism in the Department (Environment Canada) : The English and French languages are the official languages of Canada for all purposes of Parliament and Government of Canada, and possess and enjoy equality of status and equal rights and privileges as to their use in all the institutes of the Parliament and Government of Canada. Canadians should be able to receive service from, and to communicate with the federal government in either English or French, whichever is the language of their choice. Following this policy, the WSC endeavours to respond to all requests in the language in which they are requested. 5

339 4.0 SUPPLYING HISTORICAL DATA TO USERS As defined in Section 3, historical data include all years for which data have been published. For example, the 1986 hydrometric data were published in the Surface Water Data series in June As described in Section 2, the historical data are stored in two locations, in Ottawa and in the regions. Therefore the data will be supplied to the user from one of these two offices, depending upon the type of data and media requested. 4.1 DATA PUBLICATIONS History of Data Publications I. The Water Resources Branch and its predecessors have been publishing hydrometric data since the conception of the organization in the early 1900s. Originally, the data were typeset and water-year data were published every two years in a Water Resources Papers series. This series was prepared by major drainage basin, e.g., Pacific Drainage, and a total of 148 volumes were published before These older publications are out of print and are usually not available for distribution to users. Many of the publications from the early 1900s contain an abundance of photographs and descriptive information about river basins and gauging stations, which could be very useful for historical purposes, data review and for hydrologic studies. II. III. IV. In 1964, data were published in a new format within a new series entitled Surface Water Data. The series was published by province (or region) rather than on a drainage basis. The publication was typeset annually by water-year. In the late 1960s, historical hydrometric data were stored on magnetic tape. New methods were used to produce the publications, starting in The data pages could now be produced from computer output, which reduced publication preparation time from several years to one year and eventually to six months. The data continued to be published by province or region, in the same series, but data were now prepared by calendar year and two station-years were printed per page. Sediment data for the years 1948 to 1960 were published in the Water Resources Paper No. S-1. The second issue was a biennial publication covering the water years 1962 and The third issue, No. S-3, was a single year publication for the year Subsequent editions titled Sediment Data, Canadian Rivers, have been published annually. V. Commencing in 1984, sediment data were published in a new format wherein Canada was divided into eight regions. The provinces each represent a separate region except for New Brunswick, Newfoundland, Nova Scotia and Prince Edward Island, which together form the Atlantic Provinces. The Yukon and Northwest Territories make up another region. Additional information on the history of the Water Resources Branch data publications can be found in the introductory material to the historical data publications. Currently available data publications are discussed in the next section. 6

340 4.1.2 Data Publications Available The following data publications are currently available : Surface Water Data Sediment Data Historical Water Levels Summary Historical Streamflow Summary. Each of these series contains eight publications produced by province or region. The programs for producing the data pages are written and maintained by the Data Control staff in Ottawa. Manuals describing the procedures for preparing each publication have been made up by the programmers. The manuals are available in each WRB office for reference. A general description of the various WRB data publications is given in Chapter 3 Supplying Data to Users, which should be referred to at this point. Also review the introductory pages of the most recent data publication. Introductory text is updated for each publication and always contains the latest information. The schedule for the preparation of the data publications is included with a general description of the various publications. Publications series may be produced annually, every second year, or less frequently Distribution of Data Publications Data publications are prepared by the Data Control Section in Ottawa and printed by commercial printers with the assistance of the Editorial and Publications Division, which handles all the details of manuscript preparation and printer contracts. The quantities of each publication are determined by the Data Control Section. Publications are distributed in three ways : 1. The Data Control Section (DCS) manages a mailing list of over 700 names for WRB publications. As each publication is produced, the DCS supplies the Department of Environment Distribution Centre in Hull, Quebec, with address labels retrieved from the mailing list, and the Centre distributes the publication according to the label instructions. This Centre is responsible for storing and distributing Environment Canada publications. 2. The Department of Supply and Services (DSS) maintains a list of approximately 200 Full Depository libraries worldwide, which receive complimentary copies of all government publications. An extra 200 copies are printed for this purpose and go directly from the printer to DSS. 3. The Data Control Section also has a list of quantities of publications that the regional offices require. At their request, the Distribution Centre makes a bulk distribution to the regional offices. The regions are responsible for sending copies to their sub-offices, as required. Subsequent distribution of publications then occurs on an as requested basis. Requests can be made in person, by telephone or by letter to any of the WRB offices. The regions can order additional copies from the Distribution Centre. Approximately 100 copies are available for these requests Water Resources Branch Mailing List The publication mailing list is managed by the Data Control Section in Ottawa. It is updated in response to users' requests approximately twice a year. Every year a questionnaire is sent to all data users on the mailing list. Users are asked to provide information on the type and quantity of publication they require. Those who do not respond 7

341 are deleted from the mailing list. Requests for additions or changes to the list can be sent directly to the Data Control Section in Ottawa or can be channelled through regional data control sections. The mailing list is located in the Crowntek computer in Toronto. Each publication is identified by a unique number referred to as a tab. A sample of the questionnaire and mailing list is included in Appendix C. A copy of the entire mailing list is supplied to each of the regional Data Control Sections annually for verification and retention. The mailing list is usually sorted by postal code within each province, but other retrievals such as by user identification are also available. 4.2 MICROFICHE From 1980 to 1986, all historical data for all provinces were reproduced annually on microfiche by the Data Control Section in Ottawa. Like the data publications, these microfiche were supplied to users on the mailing list, and a supply was sentto the regional offices. The remainder were retained by the DCS in Ottawa to answer future data requests. A copy of the letter that accompanied the distribution of the microfiche is reproduced below. An explanation of microfiche is also given in Chapter 4 of the Supplying Data to Users Manual. Since 1986 microfiche have not been produced as a standard format for data dissemination. However, in some instances, the regions have requested that microfiche continue to be prepared for their province. In these cases the microfiche have been prepared by headquarters and provided to the regional office for distribution. Resources Branch Ottawa, Ontario K1A 0H3 March 1986 Historical hydrometric data to 1985 on microfiche Historical hydrometric data to 1985 are now available on microfiche. Hydrometric data include daily discharges (FLOW) and daily water levels (LEVELS). The data are produced on microfiche in station number order by province. There are 270 frames or printouts per microfiche at 48X reduction; there is also a visible heading showing the fiche number, type of data, region, the beginning and ending station number and year of data and the month/year that the fiche was created; the last frame is an index of the contents of that fiche. There is also a Master Index for hydrometric data on three fiche for all stations in Canada. The station number, region, type of data, province, fiche number and the station name will appear in each of the three fiche : one by station number order, or alphabetically by station name, and the third by province in station number order. Historical hydrometric data on microfiche will continue to be distributed each year to users on the WRB mailing list, or upon request to the appropriate regional office, or Headquarters in Ottawa. Head Data Control Section 8

342 4.3 MAGNETIC TAPE Users requiring data for use in computer-compatible form generally request the data on magnetic tape. These requests are referred to the Data Control Section in Ottawa, where the data are retrieved from the HYDAT system and copied onto tape. Users are requested to supply their own tape(s). Only specific types of data are supplied on magnetic tape, and only in specific formats. These formats are explained in Chapters 2 and 7 13 of the Supplying Data to Users Manual. A copy of this manual is supplied to all users with their magnetic tape request. These chapters should be reviewed carefully. 4.4 FLOPPY DISK The continued growth in the use of personal computers in the workplace has resulted in a demand for hydrometric and sediment data in a format compatible with these machines. Requests for small amounts of data can be provided on an IBM compatible floppy disk by the Data Control Section in Ottawa. A floppy disk can store about 550 station years of daily discharge values. Requests involving more than four or five disks would normally be answered using other media such as computer tape. The data copied onto floppy disk are in exactly the same card image formats as for tape requests (Section 4.3). 4.5 INTERACTIVE USER RETRIEVALS It is possible for frequent users of WRB data to perform their own data retrievals. I. The first requirement is to get an account at the Computer Services Centre (CSC), Department of Energy, Mines and Resources (where the WRB data bank is maintained). II. The second stage is to run a software package prepared by the Branch entitled Interactive Procedure for Automated Retrievals (IPAR). IPAR is a user friendly, interactive procedure by which the user communicates, via a monitor or hardcopy terminal, with CSC computer in Ottawa. The dialogue consists of questions concerning the data request asked by the system and responses typed in by the user. A full explanation of the procedure is given in the IPAR Users' Manual. Data that can be extracted from HYDAT are shown on the IPAR Menu of Codes and Types of Retrievals listed below. Cod e Type of Retrieval Cod e Type of Retrieval Discharge Data (m³/s) Sediment Data Daily mean Annual max. and min. daily mean Annual maximum instant. peak Monthly and annual mean Hydrographs Water Level Data (metres) 21 Suspended conc (mg/l) Other Data Daily mean Annual max. and min. daily mean Hydex retrievals Sedex retrievals 9

343 14 15 Annual maximum instant. peak Monthly and annual mean Hydrographs Most data can be retrieved onto tape, disk (disk file at EMR) or listings, but the format may vary depending on the output medium. The examples given in the IPAR manual indicate the output medium. 4.6 HYDROGRAPHS Three types of hydrographs of historical daily values are available upon request to the Data Control Section in Ottawa : a. annual (individual year), b. continuous, and c. comparison. The hydrographs are plotted on white paper to the same scale as the standard Water Survey of Canada hydrograph forms. They are explained in greater detail in the IPAR Users' Manual, Sections 4.5 and 5.5, which should be reviewed at this time. 4.7 STATISTICAL PLOTS A number of statistical plotting routines are now available for supplying data requests. Appendix D contains the Plot Request Form, showing the various types of plots available. These plots are fully described, showing sample outputs, in the Station Review Plot Package prepared by J.L. McIlhinney of the Sediment Survey Section. Instructions are included in the manual to assist interactive users in retrieving their own plots. 4.8 HOURLY DATA Users frequently request hourly data for historical periods. As mentioned in Section 2.3, all historical digital data are stored in the SAVE files in the regional offices. The requests are therefore sent to the regional Data Control Section for reply. Requests for hourly data can be quite time-consuming for the staff because research often has to be done to determine the stage discharge curve, and it takes time to update cards if there have been any revisions. The user should be asked to specify the particular periods or floods when the data are required. Hourly data are only available : For periods operated by an automatic recorder When the gauge was operating during the required period When the chart was digitized for the period When updating corrections were not used. A thorough discussion should be held with users requesting these data. The limitations of producing accurate hourly data and an understanding of how the data will be used should be covered. Because hourly discharge data may not be accurate due to many factors such as variable backwater, unsteady flow or lack of stage data, careful examination of the stage and related data must be made by an experienced person before releasing this information. Hourly concentration data are available for stations that have a concentration curve constructed, providing the chart or curve was digitized. 10

344 Hourly data are generally supplied to the users on computer listings. 11

345 4.9 STAGE DISCHARGE TABLES As a general rule, the stage discharge table is provided only to selected users. This is because many users are not familiar with hydrometric data computation procedures and incorrectly apply the table to water levels for the entire period of record (and wonder why they get different results) or to water levels at other locations on the river. Before giving out the tables, staff should ensure that the user is aware of the limitations of applying any stage discharge relationship. It is a good practice to encourage the user to visit the office so that there will be opportunity to explain how the table can be used. Stage discharge tables are retained in the regions and the originals are usually on file in the Work File. A copy of the original form of the computer listing may be provided to the user RECORDER CHARTS Historical recorder charts are retained by the regional offices either in their own storage area or at Public Archives. Requests for copies of these charts are therefore completed in the regional offices. Usually, requests of this nature are for specific flood events, and only certain periods are requested. Occasionally, for a particular study, a user may want copies of the entire period. Users should be made aware that it may not be possible to make a continuous copy of the chart if a blueprint copier is not available. Depending upon the request, some users may prefer to visit the regional office and spend time examining the charts and extracting the information they need. Others will want copies. It is beneficial to encourage a user to visit the office and examine recorder charts (or other data) and discuss the data with staff members familiar with the users' areas of interest. Requests for small quantities of charts are photocopied in the office; large quantities are sent out to commercial companies by some regions and billed to the user METER NOTES Historical meter notes are retained by the regional office either in their own storage area or at Public Archives. Requests for copies are therefore completed in the regional offices. Depending upon the information requested, users may be supplied with copies of the Discharge Measurements form ( R56), the Miscellaneous Discharge Measurements form ( R56A), the Hydrometric Survey Notes cover sheet (IW 2078 R21) or the full measurement. Users requesting river cross sections are generally supplied with copies of the meter notes. As with recorder charts, some users may prefer to visit the regional office and extract the information, while others will want photocopies. Recent measurements have been stored on computer using procedures, and it may become the practice to supply printouts when responding to requests for measurement data. There is also a MEASUREMENTS file established in Ottawa, which will be used for historical measurement requests but is not operational at the present. Field sampling notes (R-250), laboratory analysis summary sheets, and sediment measurement notes can only be supplied through the regional Data Control Section. 12

346 5.0 SUPPLYING CURRENT DATA TO USERS As defined in Section 3.0, current data are data that were not published before the date of the requests. Current data are stored in the regions only. Depending upon the station, and the organization of the region, the data may be in a sub-office or in the regional office, or both. Data requests will therefore be supplied from the appropriate office. Requests for Tonnes data must be forwarded to the DCS for response because the regions do not have the capability to run the Tonnes program. 5.1 PROVISIONAL DATA Many users require data for as long a period as possible, which includes the current year. Historical data can be provided by Ottawa (or regional offices), but the current data are available only from the regions (regional office or sub-office). Current data are usually provided on printouts and are flagged as Provisional Data. This includes daily values, monthly/annual means or instantaneous values. During seasons of drought or extreme high water, the frequency of requests for current data increases. These are often telephone requests for the most recent data available. 5.2 STANDING REQUESTS Many agencies require data for particular sites on a regular basis. This may be weekly, bi-weekly or monthly. As much as possible, the WRB attempts to accommodate these requests. Most require additional field work by the technicians to collect and compute the data. In many cases, these gauge sites are equipped with electronic transmittal equipment to facilitate the data collection. 5.3 HOURLY REQUESTS Requests for current hourly data for automated stations can easily be handled locally, provided the data are on computer file. If the files are not up-to-date there may be a delay until the chart has been removed and digitized, or the stage-discharge relationship has been confirmed, or the gauge/shift corrections are computed. Naturally, hourly data are only available if the gauge has been recording accurate water levels. Hourly data are generally supplied to users on computer listings. 5.4 REAL-TIME DATA In recent years the ability to transmit data via telephone line or satellite has made it technically possible to produce provisional real-time data. This has caused the WRB to face new questions concerning the responsibility of responding to the increasing demand for real-time data. Not all of these questions have been answered; but some temporary decisions follow : a. The WRB has decided not to attempt to provide real-time data. This would involve transmitting data to the regions at least hourly throughout the day and night, which would be much too costly. It would also involve unscheduled trips to stations for maintenance whenever the data collection or data transmittal system broke down. It was decided to provide near real-time data. This means transmitting the data to the regions once a day only (provided that the equipment is working) and conducting maintenance on scheduled trips only. 13

347 b. It would be difficult to ensure that all data provided, even on a near real-time basis, were accurate. Users retrieving these data must therefore accept them as unverified data. c. The procedure for processing the data and making it available to users must be automated to the extent that it can be handled routinely. The procedures for processing and distributing near real-time data vary with each region and will continue to change for some time to come. Special efforts will be made to accommodate users, but until the WRB/AES Direct Readout Ground Stations are in operation with new software and hardware at these stations and in the region, there will not be a standard procedure for supplying the data to users. 5.5 OTHER CURRENT DATA The procedures for supplying historical data such as stage-discharge tables, gauge charts, meter notes, sediment notes and hydrographs are explained in Section 4. The procedures for supplying current data are virtually the same except that since the data are currently being collected, the retrieval procedure is much easier and quicker. 5.6 SEDIMENT DATA The region can respond to requests for concentration data listings, field sampling notes, and provisional laboratory analysis. If historical tonnes or current tonnes are required, requests must be channelled through DCS. 14

348 6.0 SUPPLYING OTHER DATA TO USERS As defined in Section 3, other data include : requests for maps, station descriptions, benchmark elevations, general publications, reference indices, manuals, HYDEX SEDEX retrievals, and other information. 6.1 GENERAL PUBLICATIONS The Water Resources Branch prints a number of publications that are not part of the data series but contain information for general or internal use. These publications can be made available to users upon request Reference Indices The following two reference indices are published every two years and are distributed (same as for the data publications, Section 4.1.3) by the Water Resources Branch : Surface Water Data Reference Index, and Sediment Data Reference Index. These books list all the hydrometric stations in Canada. They serve to inform the user of what data are available and at which locations. These publications are an invaluable tool for the user, and often the first step in answering a request from an uninformed user is to supply a copy of the appropriate index so that the user can specify exactly what data are required. Examine the contents of the two publications. The contents are explained in the introductory pages Explanation of Reference Index Publication Section, which should be reviewed point by point. Note also the order in which the stations are listed in the reference indices. Both indices contain references from across Canada which are divided by province in alphabetical order. The stations are then listed : 1. Sediment Data Reference Index alphabetical by station name. 2. Surface Water Data Reference Index stream order. Stream order is used so that all stations on a stream or in a basin are listed together in the book. To become familiar with how the stations are sorted, refer to Appendix E Listing Gauging Stations by Stream Order Surface Water Data Reference Index Map Supplement The present publication schedule indicates that hydrometric station maps will be produced on a four-year cycle to supplement the reference index. These maps are prepared at headquarters with the same distribution as the reference index. Additional maps are available for responding to user requests, by headquarters or regional staff. These maps show users where hydrometric data are available. An explanation of the available maps is included on the map sleeves. This explanation is given in Appendix F for review HYDEX SEDEX Retrievals An inventory of the latest conditions at all active and discontinued gauging stations in Canada is stored on magnetic files in Ottawa. The statistics in these files are used for publications, cost-sharing agreements, network analysis, inventory control and management decisions. Most requests for retrievals from these files come from 15

349 within the Branch, although occasionally outside users require special information. There are two types of retrievals : summaries and lists. i. The summary adds up all the stations in one category and gives totals of the number of stations in each category. ii. The list merely points out all the stations that fall within the specific category. Summaries are usually tailor-made for a specific requirement, whereas lists are normally much more flexible and are used to determine which stations fulfill a specific set of criteria. The HYDEX System Operations Manual, fifth edition, 1980, Chapter 9, explains in detail (with examples) the retrievals available from HYDEX. Most requests for information from HYDEX or SEDEX are handled by the Data Control Section in Ottawa. However, most regions have accounts on the EMR computer in Ottawa (where the data are stored) and are capable of making their own retrievals Manuals Manuals prepared by the headquarters staff of the Water Survey of Canadaare mainly procedural manuals, written to maintain standard procedures across Canada. They are primarily internal manuals for a specific audience, e.g., field manuals are used mainly by field technicians while publication manuals are used, by the Data Control staff in Ottawa. However, these manuals can be provided to other users if requested. Provincial agencies and foreign countries frequently request WSC manuals Study Reports A number of study reports have been prepared over the years, mainly by the Hydrology Division and Sediment Survey Section. Some have been prepared under contract. Usually, the reports are written for a special purpose or a special audience, and only a limited number are printed. However, these reports or photocopies can be provided to users upon request. Requests for study reports should be channelled through the author Regional Data Publications Various regions have undertaken to produce miscellaneous data publications on the following subjects : Miscellaneous discharge measurements Water temperature Ice thickness Velocity and cross sections N-Day maximum or minimum flows Snow surveys. At one time a national list of these regional data publications was kept, but it is now out-of-date. Copies of publications are probably on file in the regional libraries. Requests for data that may have been published should be channelled through the regional Data Control Staff. 6.2 STATION DESCRIPTIONS Users requiring more specific information about the gauge site are frequently supplied with copies of the Station 16

350 Description. The original Station Description should be filed in the Work File where it is accessible to anyone in the office. Some regions also retain copies of the sub-office Station Descriptions in the regional office for answering requests. 6.3 BENCHMARK ELEVATIONS Another common request is for the elevation of specific benchmarks. Because the benchmark elevations are stored only on paper forms in the work files, all requests must be forwarded to the appropriate office for reply. The unique identifier on each benchmark assists the user when requesting elevations. 6.4 GENERAL INFORMATION Many requests from users are very general, i.e., individuals wanting information on water but not necessarily hydrometric data. Every effort should be made to assist the user by referring him/her to the proper organization or perhaps by supplying information from one of the sources in the following sections Pamphlets There are a number of general information pamphlets prepared by the Water Resources Branch, the Inland Waters Directorate, and the Conservation and Protection Service, on specific subjects (e.g. acid rain), programs (e.g. surveying Canada's water) or concerns (e.g., taking water for granted). These pamphlets are usually produced in bulk and supplied to all offices. They are handy for requests or for handouts when giving talks or at displays. Additional copies may be obtained by the regional Data Control staff by ordering from the Distribution Centre in Hull WATDOC WATDOC is the database producer of the Inland Waters Directorate, offering to the scientific and technical community a package of publicly available databases. The databases provide full bibliographic citations, keywords, and abstracts for Canadian water and environment related documents, data collections, and operational hydrological technology. WATDOC is part of the Water Planning and Management Branch, Water Management Systems Division, at headquarters. Users researching a particular hydrological subject or studying a specific area can locate all pertinent articles through a search of the WATDOC databases. These databases are available on-line from many of the major public libraries, university libraries, and departmental libraries. Users who want information on how to gain access to the databases to do their own searches should contact : WATDOC Inland Waters Directorate Environment Canada Ottawa, Ontario K1A 0H3 (819) Inland Waters Directorate Publications The Editorial and Publications Division (EPD) of the Inland Waters Directorate has a mandate for maintaining editorial, design and printing standards for IWD publications originating in headquarters, the national research institutes and all regional offices. These publications are subject to federal, departmental and IWD publications policies, directives and publishing guidelines. To ensure that these policies are being followed, copies of all 17

351 publications, whether they are intended for wide or limited distribution, should be sent to the EPD before being released for publication. EPD maintains a comprehensive list of IWD documents, which is published regularly as the Inland Waters Directorate Publications list. The list is divided into the following sections : Scientific Series Technical Bulletin Series Report Series Social Science Series Data Series Water quality reports Miscellaneous publications Flood Damage Reduction Program publications General interest brochures. For further information, refer to the IWD Publications List or the IWD Publishing Policy and Guidelines manual. Users' requests for any of these publications may be forwarded to : Editorial and Publications Division Inland Waters Directorate Department of the Environment Ottawa, Ontario K1A 0H3 (819) Provincial Publications The provinces also produce data publications for sites not covered in the WRB network. These publications are not listed in any of the federal publications. However, most regional offices are aware of the activities of their provincial agencies and have copies of the provincial data publications in their libraries. User requests for these data publications should be forwarded to the appropriate address. 18

352 7.0 REPORTING PROCEDURES Each region has its own procedures for documenting data requests. These are recorded in monthly reports by the regional Data Control staff. The Data Control staff at headquarters also keep record of all requests responded to by the Water Resources Branch and the Distribution Centre, on a monthly basis. Annually, in June, the regional offices send a report to headquarters summarizing their user requests in a national format. It is then possible for the Data Control Section in Ottawa to do a national roll-up in a report entitled Water Resources Branch Data Dissemination Summary. These reporting procedures permit analysis of user requests with respect to national and regional trends of types of users and types of requests. These analyses assist managers in determining which data are most useful and by what media the data should be provided to give the best service to our users. 19

353 8.0 SUMMARY The technician should now be aware of : 1. the various types of data which can be supplied to users, 2. where the data or information are located, and 3. the identity of the appropriate person to respond to the request. The technician should also have a greater appreciation of the wide demand for hydrometric data for a wide range of users. The information collected by the Water Survey of Canada is vital for the intelligent management of our resources. Following the completion of this lesson package the technician will realize how important it is to work with users in order to provide complete and accurate data in a format which will readily meet their needs. 20

354 9.0 MANUALS AND REFERENCES 9.1 MANUALS Environment Canada (1980), Manual of Hydrometric Data Computation and Publication Procedures, Fifth Edition, Inland Waters Directorate, Internal Report, Ottawa. Environment Canada (1980), Manual of Hydrometric Data Review Procedures, Fifth Edition, Inland Waters Directorate, Internal Report, Ottawa. Environment Canada (1980), Supplying Hydrometric and Sediment Data to Users, Second Edition, Inland Waters Directorate, Internal Report, Ottawa. Environment Canada (1981), SAVE File Operations Manual, Second Edition, Inland Waters Directorate, Internal Report, Ottawa. Environment Canada (1981), LEVELS File Operations Manual, Second Edition, Inland Waters Directorate, Internal Report, Ottawa. Environment Canada (1981), PEAKS File Operations Manual, Second Edition, Inland Waters Directorate, Internal Report, Ottawa. Environment Canada (1981), Publication Procedures for Surface Water Data Reference Index, Second Edition, Inland Waters Directorate, Internal Report, Ottawa. Environment Canada (1981), Publication Procedures for Surface Water Data, Second Edition, Inland Waters Directorate, Internal Report, Ottawa. Environment Canada (1981), Publication Procedures for the Historical Streamflow Summary, Second Edition, Inland Waters Directorate, Internal Report, Ottawa. Environment Canada (1981), Publication Procedures for the Historical Water Levels Summary, First Edition, Inland Waters Directorate, Internal Report, Ottawa. Environment Canada (1983), FLOW File Operations Manual, Fourth Edition, Inland Waters Directorate, Internal Report, Ottawa. Environment Canada (1984), Sediment Data Files Operations Manuals, Inland Waters Directorate, Internal Report, Ottawa. Environment Canada (1986), IPAR User's Manual, Inland Waters Directorate, Internal Report, Ottawa. 9.2 REFERENCES Environment Canada, Water Resources Branch Data Publication Series Surface Water Data (Annual) Historical Streamflow Summary (Biennial) Historical Water Levels Summary (Biennial) Sediment Data (Annual) Reference Index Surface Water Data (Biennial) Reference Index Sediment Data (Biennial) Inland Waters Directorate, Ottawa 21

355 Northern Affairs and National Resources, Water Resources Paper Series. From 1905 to 1964, 148 publications were prepared by the Water Resources Branch, Ottawa. Water Resources Branch, Data Dissemination Summary, Annual Internal Report, Ottawa. Water Resources Branch, Mailing List, Printout listings supplied to regions by Ottawa. Environment Canada, Publications-1986, Inland Waters Directorate, Editorial and Publications Division, General Information Publication, Ottawa. Environment Canada (1986), Publishing Policy and Guidelines, Inland Waters Directorate, Editorial and Publications Division, Ottawa. Campbell, P.I. (1975), Uses of Water Resources Data, Environment Canada, General Information Bulletin, Ottawa. McIlhinney, J.L. (1986), Station Review Plot Package, Environment Canada, Sediment Survey Section, Internal Report IWD-HQ-WRB-SS-86-10, Ottawa. Environment Canada (1973), Policy on Bilingualism in the Department, General Information Booklet for Employees, Ottawa. 22

356 APPENDIX A: SAMPLES OF INTRODUCTORY TEXT TO PUBLICATIONS (to be supplied by trainer) 23

357 APPENDIX B: SAMPLES OF DATA PUBLICATIONS (to be supplied by trainer) 24

358 APPENDIX C: QUESTIONNAIRE AND REPLY CARD Figure 1: Questionnaire and Reply Card (part 1 and part 2) Figure 2: Questionnaire and Reply Card (part 3) 25

359 Figure 3: Questionnaire for Users of WRB Publications Figure 4: Questionnaire for Users of WRB Publications (continued) 26

360 APPENDIX D: PLOT REQUEST FORM Figure 6: Plot Request Form (continued) Figure 5: Plot Request Form 27