P - R P ET ± S P P P - R = Criss

Size: px
Start display at page:

Download "P - R P ET ± S P P P - R = Criss"

Transcription

1 P - R P P - R = ET ± S P P Criss

2 Criss

3 Class A Evaporation pan watershed USGS

4 WATER PROFILE!!!Vadose Zone (Unsaturated Zone; Zone of Aeration) Solid, Liquid & Gas Phases!!! Soil Water!!! Intermediate Zone:!!!!!Thin film of water on pore linings; free to drain.!!!!!thickness variable; 100's ft in arid zones!!! Capillary Water: water held up by surface tension!!!!!cannot pump!!!!!ppore < 1 atm! measure with a tensiometer!!!water Table!!!Streams & lakes = intersection of water table with Earth s surface!!!!p = 1 atm!!!!!phreatic Zone (Saturated Zone)!

5 WATER PROFILE Unsaturated Vadose Zone Water Table Soil Water Intermediate Water Capillary Water Saturated Phreatic Zone Ground Water Water in unconnected pores Chemically -bound water

6 2r h c = 0.153/r? C D PA = PC = 1 atm h c PB =? B A PD =? after Domenico & Schwartz 1990

7 2r h c = 0.153/r? C D PA = PC = 1 atm h c PB = 1 atm B A PD = 1 - ρ g h c after Domenico & Schwartz 1990

8 2r C D h c = 0.153/r UNITS? LIMTS? PA = PC = 1 atm h c PB = 1 atm B A PD = 1 - ρ g h c after Domenico & Schwartz 1990

9 WATER PROFILE well Unsaturated Vadose Zone Water Table Soil Water Intermediate Capillary Water?? Saturated Phreatic Zone Ground Water?? Water in unconnected pores Chemically -bound water

10 WATER PROFILE well Unsaturated Vadose Zone Water Table Soil Water Intermediate Capillary Water P=1 atm Saturated Phreatic Zone Ground Water Water in unconnected pores Chemically -bound water

11 Craig et al. 1996

12 USGS

13 Rising River, CA ~400 cfs Criss

14 Gaining & Losing Streams:!!!Gaining Streams: Receive GW from base flow;!!!!!! Case where is above stream base!!!losing Streams: Lose water to GW reservoir!!!!!! Case where is below stream base!! Note: A gaining stream can become a losing stream during flood stage! => Bank Storage!! Most streams in USA mid-continent are gaining streams.! Otherwise, would be bone dry every few days! if not for base flow, like western streams!! Exception: karst dry valleys!

15 Gaining Stream Losing Stream Losing Stream disconnected from water table USGS Circ 1186

16

17 QUESTIONS: What do we need to know? What happens to rainfall after it is delivered? Path, transport mechanisms, river response How are hydrologic data measured & calibrated? What is the relationship between Stage & Discharge? How does discharge relate to basin characteristics? What can be learned from Hydrographs? What are the mathematical properties of the Hydrograph? How can predictive models be made? How can flood probabilities be determined?

18 QUESTIONS: What do we need to know? What happens to rainfall after it is delivered? Path, transport mechanisms, river response How are hydrologic data measured & calibrated? What is the relationship between Stage & Discharge? How does discharge relate to basin characteristics? What can be learned from Hydrographs? What are the mathematical properties of the Hydrograph? How can predictive models be made? How can flood probabilities be determined? Hydrograph!!= plot of discharge vs. time or!!= plot of stage vs. time!

19 Aug Aug Aug Sept

20 OVERLAND BASE FLOW USGS

21 PRECIPITATION EVENT!! Different zones give rise to different runoff components:!!!surface =>!Interception (plants) (Golfers & lightning)!!!!!!depression storage!( puddles )!!!!!!Overland Flow!!(Surface Runoff)!!!Vadose Zone (above water table)!!!!!=>!storage (Field Capacity) ( moisture limit under gravity)!!!!! Interflow!!(Runoff from vadose zone, if exceed F.C.)!!!!!!GW recharge!!( if exceed F.C.)!!!Phreatic Zone (below water table)!!!!!!=> Base Flow!!(Runoff from phreatic zone, if exceed F.C.)!

22 Unsaturated Vadose Zone Water Table WATER PROFILE Soil Water Intermediate Water Capillary Water Overland Flow Interflow Saturated Phreatic Zone Ground Water Base Flow Water in unconnected pores Chemically -bound water No Flow

23 Ro ET E DeWiest 1965

24 Overland Flow: Horton (1933, 1940)!! = Classic model for streamflow generation!!!during rain event, infiltration rate decreases exponentially w/ time!!!!! If ppt rate < inf. cap then soil infiltration occurs!!!!!!if ppt rate > inf. cap then overland flow occurs!!!! Overland flow is inevitable for heavy rain!!!!infiltration capacity f (in m/s): f = fc + ( fo -fc ) e -ct!! Actually:!!!!!!f is the infiltration rate!!!!! f => fc, a constant that depends on the hydraulic conductivity K of!!!!!!!!!!the saturated soil (F&C, p. 212).!!!!Curve realized for heavy rains!!!!!!where!!!!!!!!fc = equilibrium capacity!!!!!!!!fo = initial (t=0) infiltration capacity!!!!!!!!c = constant (but must depend on rain amt & intensity)!

25 Ro ET E DeWiest 1965

26 Is base flow maximized or minimized during peak streamflow? Look at real systems. Criss (2003) after Fetter (2001) & Freeze & Cherry (1979)

27 Meramec River, Oct Stage 1.8 ft. Discharge 500 cfs Criss

28 Meramec River, May 2000 Stage~27.8 Q ~56,000cfs Criss

29 Rockwoods Spring, 3/1996 Criss

30 Rockwoods Spring, May 2000 Criss

31 Fetter, 2001 Poor Boundary Freeze & Cherry, 1978 More realistic, but how can the Proportions be Quantified? Criss 2003

32 Chemical Method of Hydrograph Separation Total = Direct + Ground Streamflow Runoff Water Q sf = Q of + Q bf C sf Q sf = C of Q of +C bf Q bf Q bf Q sf = # C sf "C of % $ C bf "C of & ( '

33 500 Meramec River at Eureka USGS WQ data EC bf 400 Q bf Q sf = EC sf! EC of EC bf! EC of EC, µs/cm C sf = ( C bf! C of ) Q bf Q sf + C of EC of Q cfs

34 How to quantify Proportions? Isotopic Method of Hydrograph Separation Criss (2003) after Fetter (2001) & Freeze & Cherry (1979)

35

36 NATURAL WATERS Oxygen & Hydrogen: Ideal, double isotopic tracer system 18 O, D, T Conservative tracers Intrinsic to the H 2 O molecule δd vs. δ 18 O plot Historical note: Epstein vs. Friedman approach, then Craig 1961

37 HYDROGEN ISOTOPES PROTIUM DEUTERIUM TRITIUM PROTIUM DEUTERIUM TRITIUM 1 H 2 H 3 H 1 H 2 H 3 H

38 ELEMENT ISOTOPE ATOMIC WEIGHT amu ABUNDANCE atom % HYDROGEN z = H Protium H Deuterium CARBON z = C C OXYGEN z = O O O

39 MAT 251 Criss

40 H2O Equilibrator Criss