Monitoring Saturated and Un-saturated Zone Processes for Improving Integrated Modeling

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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

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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

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Why Collect Data?Answer Fundamental

• Groundwater upward flux (capillary fringe)?
• Vadose zone or water table recharge?
• Variable specific yield?
• Air entrapment

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Site Location
Hillsborough County
F L O R I D A
Reservoir Site Location
Reservoir Site Location
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Instrument Locations
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Installed InstrumentationWeather

• 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

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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)

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Streamflow Monitoring
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Streamflow Analysis
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Well Transects
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Well Transect Data
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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

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Runoff Test-bed
ATION in Feet
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Runoff Test-bed Schematic
Monitoring wells
Perimeter Flashing
100
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Overland Flow
Weir
Soil moisture probes
Gutter
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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
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Runoff Test-bed Photographs
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Runoff Test-bed Data
June 25-26, 2002
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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

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Soil Moisture Probes Installation Photographs
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Soil Moisture Probes Photographs
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Geo-probe Soil Sampling
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Soil Texture Analysis
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Soil Moisture Profiles
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Soil Moisture Profiles
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Variable Specific Yield
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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

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Soil Moisture Profiles