THE STATE OF SURFACE WATER GAUGING IN THE NAVAJO NATION

Transcription

1 THE STATE OF SURFACE WATER GAUGING IN THE NAVAJO NATION Aregai Tecle Professor of Hydrology Northern Arizona University Flagstaff, AZ Acknowledgement Many thanks to my research team mates and Elisabeth Alden for taking the photographs

2 A MEASUREMENT OF STREAM DISCHARGE RATE IS NEEDED FOR PRECISE ESTIMATE OF THE TOTALAMOUNT OF WATER LEAVING A WATERSHED. THE WATER COMES FROM SURFACE AND SUBSURFACE SOURCES. KNOWLEDGE OF THE AMOUNT OF FLOW IS IMPORTANT FOR MANY REASONS.

3 PURPOSES OF STREAM GAUGING To enhance the public safety by providing data for forecasting and managing floods To delineate and manage flood plains To characterize current water-quality conditions To operate and design multipurpose reservoirs To design highway bridges and culverts To set minimum flow requirements to meet aquatic life goals To monitor compliance with minimum flow requirements To develop or operate recreation facilities To allocate water for municipal, industrial, and irrigation uses To determine impacts of phreatophyte water consumption To evaluate surface- and ground-water interaction For scientific studies of long-term changes in the hydrologic

4 CHARACTERISTICS THAT INFLUENCE DATA QUALITY AND RELIABILITY INSTRUMENT RELIABILITY DATA HANDLING DATA PROCESSING INSTRUMENT MAINTENANCE DATA ACCESSIBILITY (Location) SPATIAL DISTRIBUTION AND REPRESENTATIVENESS OF DATA AVAILABILITY OF KNOWLEDGEABLE AND DEDICATED PERSONNEL

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6 STREAM GAUGING ASSESSMENT IN THE NAVAJO NATION Information sources On-site examination of stream flow gauging sites and instruments Relevant literature review Downloading available USGS data on Navajo streams Interview of relevant personnel (NDWR and USGS) Historical data acquisition

7 STREAM GAUGING ASSESSMENT IN THE NAVAJO NATION Data analysis Evaluation of NDWR stream flow data collection, reporting, communication, and integration needs Arranging data and trend analysis Comparing data from USGS and NDWR operated gauges Determining weaknesses and strengths Providing appropriate recommendings

8 CURRENT CONDITIONS OF STREAMS AND ASSOCIATED DATA IN THE NAVAJO NATION

9 SAN JUAN RIVER STREAM FLOW CHARACTERISTICS The San Juan River is operated by the USGS. Compared to those operated by the NDWR, the data can be used for many purposes. Here we use it to show the wet season in the lower right hand side and to show the decreasing streeam flow (or drying) condition in the lower left hand side. The 3-D D figure to the right shows the monthly average stream flow for 27 years. The figure can show us years of high or low flows. We can also use the data for modeling water yield and peak flow or flood forecasting 35 Streamflow rate (in cfs) Years Jan Mar May Jul Sep Nov Months Stream flow of San Juan River in New Mexico near the border with the Navajo Nation 3 5 Stream flow rate (in cfs) Annual average streamdlow (in cfs) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Years of record Months of the year A five year running average of stream flow rate (in cfs) at San Juan River Monthly average hydrograph of flow rate at San Juan River (in cfs)

10 5-year running average stream flow (in cfs) LITTLE COLORADO RIVER NEAR CAMEROON: ANOTHER EXAMPLE OF A USGS-OPERATED STREAM GAUGE year running average of Little Colorad River discharge (in cfs) near Cameroon, Arizona Monthly average stream flow (in cfs) Years of record Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 1981 Months of the year Monthly average stream flow (in cfs) of Little Colorado River near Cameron, Arizona This is a long term data which can be manipulated to show different hydrologic conditions around the area of measurement. The graphs on the right hand side show wet and dry years for 58 year, the upper one on a monthly basis in 3-D and below it as yearly average. The graphs to the left show a 5-year running average and monthly average hydrographs to show annual and seasonal behaviors of the river. Stream flow rate (in cfs) Monthly average stream flow (in cfs) Years of record Jan May Sep Months stream flow record in the Little Colorado River near Cameron, Arizona Years of data record Annual average stream flow (in cfs) of Little Colorado River near Cameron, Arizona

11 BLACK CREEK: GAUGE CONDITION Instrument has been operating continuously Data arrangement follows a USGS format Data recording has been interrupted a number of times Problems with the gauging station Stilling well & vegetation Channel invasion by vegetation Channel bed sediment accumulation Sediment accumulation

12 Oct NovDec Jan Feb Total monthly stream discharge (in cfs) Months of the year BLACK CREEK STREAMFLOW CHART Jul Aug Sep Years Mar Apr May Jun

13 ASSAYI CREEK: GAUGE CONDITION Problems with Assayi Creek 1. Invasion by vegetation 3. Data have not been regularly 2. Sediment accumulation taken and processed

14 ASSAYI CREEK DATA The graph on the left shows sporadic stream flow data while the dotted graph on the right is stage- discharge relationship of the recorded data. The chart shows little flows for high stage which can be due to errors in data recording or instrument reading. Assayi Creek Sporadic Stream Flow Measurement Stage height versus Stream flow rate for Assayi Creek Stream flow rate (in cfs) Years of record stage height (in feet) Stream flow rate (in cfs)

15 Stilling well CHINLE CREEK: GAUGE CONDITION Three major problems are apparent in this gauging station: 1) stream braiding resulting in most of the flow taking place away from the gauge, 2) lots of sediment accumulation and 3) stream bottom plant and tree growth The consequences of these conditions are both under and over estimation of stream flow

16 CHINLE CREEK DATA The graph on the left hand side shows the sporadic nature of the data collected form the gauge at Chinle,, and there is nothing one can do with such data. The dotted graph of stage-discharge relationship on the right shows low correlation between the two forms of stream flow measurement, which reflects the channel problem. Chart of sporadic flow rate data for Chinle Creek Chinle Creek stage height versus stream flow rate 45 3 Stream flow rate (in cfs) Stage hieght (in ft) Years data were taken Stream flow rate (in cfs)

17 TSAILE CREEK: GAUGE CONDITION This stream gauge is located in a very stable and clean reach and there are no problems associated with channel aggradation or degradation nor with sediment accumulation. The only problem is that the instrument is not calibrated for flows that rise well above bankful stage.

18 TSAILE CREEK DATA The measured stream flow record for the gauge at Tsaile is sporadic like those in most of the other NDWR- operated gauges. However the condition of the stream makes the stage-discharge points on the right look good. Stream flow rate chart at Tsaile Stage-discharge relationship at Tsaile stream gauging station Stream flow rate (in cfs) Stage height (in ft) Years in which stream discharge were recorded Stream flow rate (in cfs)

19 WHEATFIELDS CREEK: GAUGE CONDITION Stream flow record at Wheatfieklds gauging station The gauge is in a stable cross-section. However there is a great deal of vegetation invasion above the bankful stage to affect the accuracy of a stream flow measurement. As in the other gauges, we do not have a continuous record to make much sense of the data. Stream flow rate (in cfs) Years in which stream flow rate records were taken The higher correlation between stage and discharge at low flows comopared to at higher flows is reflective of the stream cross-section. section. It is stable near the bottom of the stilling well but have vegetation at higher level. Stage-discharge relationship of stream flow at Wheatfield gauging station Daily stage height (in feet) Daily stream flow (in cfs)

20 LUKACHUKAI CREEK: GAUGE CONDITION As the data from the other gauging stations those from Lukachukai Creek have not folowed proper protocol to provide any important information on the stream flow nor can they be used in any modeling or decision-making scheme. Stream flow rate (in cfs) Stream flow record at Wheatfieklds gauging station Years in which stream flow rate records were taken The order less spread of the stage-discharge relationship points on the right hand side graph shows the poor gauging station condition. Large sediment accumulation and in-channel vegetation growth give a false high stage height. Stream flow stage (in ft) Stage-discharge relationship at Lukachukai Creek Stream flow discharge rate (in cfs) Observe the tremendous amount of sediment accumulation along the stream bed. There is also plenty of vegetation growth along the stream bed.

21 CAPTAIN TOM CREEK: GAUGE CONDITION The are lots of boulders in the stream cross-section section where the stilling well is located. We could also see the sediment accumulation inside the stilling well. These along with the vegetation in the stream can Stream flow rate record chart at Captain Tom Creek affect the reliability of the flow data significantly Stream flow rate (in cfs) Stream flow stage height (in ft) Stage-discharge relationship at Captain Tom gauging station Stream flow discharge rate (in cfs Yearsin which stream flow records were taken

22 KINLICHEE CREEK: GAUGE CONDITION The gauge at kinlichee Creek is located under a bridge which is stable with no vegetation growth and little sediment accumulation. The effect can be see in the near-perfect stage-discharge relationship curve below Stream flow stage-discharge relationship at kinlichee Creek Streamflow rate chart at Kinlichee Creek gauging station 3 18 Stream flow rate (in cfs) Stream flow stage height (in ft) Years stream flow rate measurement were taken Stream flow discharge rate (in cfs)

23 WHISKEY CREEK: GAUGE CONDITION Daily stream flow (in cfs) Stream flow record chart from Whiskey Creek gauging station Years in which stream flow measurements were taken The flume in this station has some vegetation growth problems, but it is relatively in good condition. The stage- discharge data on the right shows this relatively in good condition Daily gage height (in ft) Stage-discharge relationship at Whiskey Creek gauging station Daily stream flow rate (in cfs)

24 SOME CONCLUDING REMARKS The condition of the different streams in the Navajo Nation and the data gathered from those streams tell us many things. 1. The NDWR operated gauges do not provide useable data because: - the gauges are not well-maintained to provide reliable data - data are not gathered following USGS protocols and if they are - the data are not properly processed for any use from most of the gauges 2. The available gauges are concentrated in a small portion of the Nation to represent hydrologic conditions in the Navajo Nation 3. The main reasons we found out are lack of manpower and lack of funding to properly operate existing gauges, put new ones, process and make data available for various uses, and to train and hire technical personal to make all these possible. 4. The currently available work force (generally consisting of two hard working technicians) is too small to handle all weather, snow courses and stream flow instrumentation in the Nation.

25 SOME RECOMMENDATIONS Since availability of accurate and reliable stream flow data are important for the various reasons stated above, we recommend that: 1. The Navajo nation consider having adequate hydrological information a priority as many conditions such as flood forecasting, reservoir operation, agricultural and domestic water supply and drought management as well as wildlife and ecosystem maintenance depend on it; 1. The federal government through the USGS and other outlets support the Navajo Nation to have proper hydrological data collection, maintenance and processing capabilities to meet its needs; 1. Develop a collaborative effort among local (Navajo) and relevant state and federal agencies to work together to ensure availability of needed hydrological information.

26 THANK YOU