1. Monitoring Saturated and Un-saturated Zone Processes for Improving Integrated Modeling
Patrick Tara, Jeff Vomacka, Mark Ross
Center for Hydrologic Modeling and Aquatic Systems
Jeff Geurink, Ron Basso

2. Why Collect Data? Determine Water Budget Terms
ET budget?
Vadose zone ET
Groundwater ET
Surface water runoff?
Infiltration excess
Saturation excess
Baseflow flux?
Surface water storage release
Groundwater storage release
12/4/2018

3. Why Collect Data? Answer Fundamental
Groundwater upward flux (capillary fringe)?
Vadose zone or water table recharge?
Variable specific yield?
Air entrapment
12/4/2018

4. Site Location F L O R I D A 12/4/2018 Hillsborough County
Reservoir Site Location
Reservoir Site Location
12/4/2018

5. Instrument Locations
12/4/2018

6. Installed Instrumentation Weather
Rainfall
Continuous tipping bucket rain gages (3 gages)
Standard NWS manual rain gages (3 gages)
Pan evaporation
Wind speed / wind direction
Temperature / humidity / solar radiation
12/4/2018

7. Installed Instrumentation Hydrologic
Streamflow (5 installations)
Complex “V”-notched weirs
Continuous stage recorders
Wells
Continuously recorded (12 gages)
Weekly manually recorded (83 wells)
Runoff test-bed (1 installed, 1 in progress)
Continuous soil moisture probes (6 installations)
12/4/2018

8. Streamflow Monitoring
12/4/2018

9. Streamflow Analysis Long Flat Creek Flow and Flow Difference 12/4/201820 40 60 80
100
120
140
160
180
8-Jul
28-Jul
17-Aug
6-Sep
26-Sep
16-Oct
5-Nov
Date
Flow [cfs]
-80
-60
-40
-20
Flow Difference [cfs]
Upstream
Downstream
Flow Difference
12/4/2018

10. Well Transects
12/4/2018

11. Well Transect Data
12/4/2018

12. Runoff Test-bed Size 100ft x 20ft (30.5m x 6.1m)
Flashed to prevent inflows/outflows
Gutter captures runoff
Weir with continuously logged precision level gage allows accurate flow measurement
Rain gage
Wells
Soil moisture probes
12/4/2018

13. Runoff Test-bed
ATION in Feet
12/4/2018

14. Runoff Test-bed Schematic
Monitoring wells
Perimeter Flashing
100’
20’
Overland Flow
Weir
Soil moisture probes
Gutter
12/4/2018

15. Runoff Test-bed Flow Measurement
V-Notched Weir plate
Overland Flow
Cross-section of runoff gutter which captures the overland flow and discharges to a weir in order to measure flow
Discharge to Land Surface via conduit
12/4/2018

16. Runoff Test-bed Photographs
12/4/2018

17. Runoff Test-bed Data
June 25-26, 2002
12/4/2018

18. Soil Moisture Frequency domain
Continuously monitors wetting as well as drying
Captures upward flux
Captures air entrapment
Typical probe includes 8 transducers spaced at 10, 20, 30, 40, 50, 70, 100, 150cm below land surface
12/4/2018

19. Soil Moisture Probes Installation Photographs
12/4/2018

20. Soil Moisture Probes Photographs
12/4/2018

21. Geo-probe Soil Sampling
12/4/2018

22. Soil Texture Analysis
12/4/2018

23. Soil Moisture Profiles
PS 41 Soil Moisture Profile
Response to 1.97 Inches of Rain on 2/22/02 20 40 60 80
100
120
140
160 5 10 15 25 30 35 45
Moisture (%)
Depth (cm)
2/22/2002 9:50
Water Table
2/23/2002 3:20
2/23/ :00
2/24/ :00
2/26/ :00
2/28/ :00
3/1/ :00
12/4/2018

24. Soil Moisture Profiles
PS 43 Soil Moisture Profile
Response to 1.97 Inches of Rain on 2/22/02 20 40 60 80
100
120
140
160 5 10 15 25 30 35 45
Moisture (%)
Depth (cm)
2/22/2002 9:50
Water Table
2/23/2002 3:30
2/23/ :00
2/24/ :00
2/26/ :00
2/28/ :00
3/1/ :00
12/4/2018

25. Variable Specific Yield
y = x 2 x R =
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18 1 3 4 5
depth below land surface (feet) S y
Estimated Specific Yield
Poly. (Estimated Specific Yield)
Variable Specific Yield
12/4/2018

26. Preliminary Results Air entrapment is an important process
Event pressurization
Prolonged encapsulation
Specific yield is not constant (shallow water table)
Small ET and recharge fluxes result in significant water table fluctuations
Saturation excess is dominate runoff process
Maybe controlled by air entrapment?
Vadose zone moisture deficit controls recharge
Rainfall intensity effects all above processes
12/4/2018

27. 12/4/2018

28. Soil Moisture Profiles
PS 42 Soil Moisture Profile
Response to 1.97 Inches of Rain on 2/22/02 20 40 60 80
100
120
140
160 5 10 15 25 30 35 45
Moisture (%)
Depth (cm)
2/22/2002 9:50
Water Table
2/23/2002 3:30
2/23/ :00
"Water Table"
2/24/ :00
2/26/ :00
2/28/ :00
3/1/ :00
12/4/2018