Hydrologic Overview & Quantities

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1 Hydrologic Overview & Quantities It is important to understand the big picture when attempting to forecast. This includes the interactive components and hydrologic quantities.

2 Hydrologic Cycle

Evaporation & Condensation Antecedent Moisture

Respiration Infiltration Variable Source Area

Concentration The sphere concept was borrowed

3 The complexity of what we are trying to accomplish. Evaporation & Condensation Antecedent Moisture Conditions The Water Budget Photosynthesis & Respiration Infiltration Variable Source Area Transpiration & Interception Time of Concentration The sphere concept was borrowed from Dr. Peter Black: Watershed Hydrology 2 nd Edition, Peter Black, 1996, Ann Arbor Press (ISBN# )

4 Models try to mimic this! Infiltration Time Series Basin Process Representation Excess Precip. Interception Storage Time Series

5 From A Basin View Excess Precip. Runoff Hydrograph Excess Precip. Model Basin Routing Unit Hydrograph Stream Routing

6 The Runoff Picture Hydrology is long term and short term. In this course we will mainly focus on the short term: Floods & flood flows. Generating runoff/high flows. Predicting/forecasting flows. Space/time scales.

7 Recipe(s) for a Flood/High Flows What causes a flood / high flow? What are the conditions? What are the types of flooding situations? Your area or other areas..

8 What Are the Defining Characteristics of a Flood? Timing rise time, recession, duration. Flows peak flows, magnitude (statistical). Precipitation intensity, duration, frequency.

9 What Controls the Timing, Flow, and Precipitation? The hydrology short term and long term. The meteorology short term (weather/storm type) and long term (climate).

10 Short Term Weather (storm type) & current hydrologic conditions

11 Watershed Characteristics Area Slope Land Use Soils Geology Climate Geomorphology

12 Some of the Right Combinations. Precipitation vs. vs.- infiltration Precipitation intensity > infiltration rate Precipitation total > infiltration capacity Storage in the system is full Human induced high water or flows Natural alterations to the watershed

13 Our Focus - Forecasting Must be both short & long term.. The combination(s) of precipitation and hydrologic conditions that lead create a potential flooding situation basin hydrology basin hydrology looks at the hydrologic budget in both the short and long term.

14 Water, basic element

15 Water resources

16 How much water is there? Distribution of Earth's Waters and Residence Times... Location of Storage Total water on earth Oceans Total Fresh Water Ice and Glaciers Groundwater Deep Groundwater Percent of Fresh Residence Time (years) Shallow Lakes Biosphere Soil Moisture Atmosphere Rivers

17 Water Resources Mean annual precipitation Europe Asia Africa SouthAmeric anorthamerica 734 mm/year 726 mm/year 686 mm/year 1648 mm/year 670 mm/year

18 Hydrological processes Clouds and atmosferic movement Precipitation Losses Interception Evapotranspiration Infiltration Depression storage Rainfall runoff Flood Routing

19 Units & Properties of Water Property Symbol Value Comments Density ~1.94 slugs/ft 3 Slug = lb*s 2 /ft (mass/volume) ~ 1.0 g/cm 3 Specific Weight 62.4 Lbs/ft 3 g (weight/volume) 9.81 kn/m 3 Specific Volume Specific Gravity s.g. 1.0 for 0 o C s.g. fluid = g fluid /g water

20 Water (gas)

21 Water (solid)

22 Water (liquid)

23 No water - desert

24 Clouds and atmosferic movement

25 Global cycle

27 Sun: energy source

28 Solar Radiation Sun: distance 150 millions of Km Energy received: 1000 W/m 2

29 Solar Radiation Differences according to the latitude

30 Solar Radiation Diferences between June and September

31 Effective Radiation Difference between received and back radiation Ri,, solar radiation,, albedo R e,, back radiation R n = R i (1- ) R e

32 Clouds Evaporation from seas, lakes and rivers

33 Clouds

34 Clouds

35 Clouds

36 Clouds

37 Meteorological phenomena twisters

38 Hurricanes

39 Cloud structure Water drops from 0.01 to 0.03 mm Weight from 0,5 to 1 gr/m 3 Growing processes up to to times initial values Water in clouds can explain 10 to 12 mm

40 Atmospheric circulation Tropical cells

41 Tropical cells

42 Water droplets Condensation Coalescence

43 Condensation

44 Coalescence

45 Droplet aggregation Raindrops up to 3 to 4 mm Terminal velocity 9 a 12 m/s

46 Water precipitation Water, snow, hail

47 Types of rainfall Ciclonical / Frontal rain Orographic Convective cells

48 Frontal rain Cold and hot air masses moving along the planete

49 Frontal behavior Hot and cold air mass friction

50 Frontal behavior Hot and cold interface

51 Frontal precipitations Associated to large areas (tens or hundreds of miles of Km 2 ) Long durations (days) and high total rainfalls but with low rainfall intensities

52 Orographic rainfalls

53 Orographic Precipitations Typical Mediterranean pattern During the fall Hot air coming from the Magreb, Mountains close to seaside Heavy rainfalls

54 Convective cells Afecting to small areas Convective cells appearing and disappearing during the rain period Can produce very intense rainfalls

55 Convective cells Scheme

56 Rainfall measurements Precipitation: : mm l/m 2 Intensity mm/h Temporal register: pluviograph or hyetograph

57 Greatest precipitation data Data on different observatories Annual precipitation Year Month Day 12 h 42 minutes mm mm 9300 mm 1870 mm 1350 mm 300 mm Hawaii, Mount Waialeale Cherrapunji,, Cherrapunji, July 1861 Reunión, n, March 1952 Reunión, n, February 1964 Holt,, Missouri, June 1947

58 Rainfall envelope Mathematical relationship P, mm D, hours 0.47 P 425D

59 Intensity Intensity,, ratio between precipitation and time Hyetograph

60 Rainfall measurements Pluviometer / pluviograph

61 Total rainfall

62 Pluviometer of intensity Tipping bucket gauge

63 Rainfall monitoring Satellites, qualitative observation

64 Rainfall radar

65 Measurement networks INM, rainfall data in 24 h SMC, shorter time series Rainfall radars

66 Rainfall data analysis Hypothesis: to study the historical rainfall data to predict future rainfall We assume the future rainfall will be the same as the previous one Climatic change effect: to study Application in hydrological studies

67 Data analysis Time series analysis Qualitative analysis Filling gaps Consistency test (doubles mass) Statistical analysis

68 Statistical analysis I Annual rainfall series Extremal distributions Gumbel Log Pearson III SQRT ET Associated values to return period of N years

69 Statistical analysis II Partial duration series, (peak( over threshold) Appropriated to return periods below 10 years

70 Rainfall data sources AEMET - SMC, time series, in Spain and Catalonia Previous work: : Lluvias máximas m en la España a Peninsular, DGC 2001

MET 3102-U01 PHYSICAL CLIMATOLOGY (ID 17901) Lecture 14

MET 3102-U01 PHYSICAL CLIMATOLOGY (ID 17901) Lecture 14 The hydrologic cycle evaporation vapor transport precipitation precipitation evaporation runoff Evaporation, precipitation, etc. in cm Vapor transported