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Nutrient and Pesticide Accounting in the Chipola River/Floridan Aquifer System—Update. This Study Jointly Funded by U.S. Geological Survey and Florida Department of Environmental Protection. Presented by Rick Hicks of FDEP And Christy Crandall of USGS. STUDY OBJECTIVES.
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Nutrient and Pesticide Accounting in the Chipola River/Floridan Aquifer System—Update This Study Jointly Funded by U.S. Geological Survey and Florida Department of Environmental Protection Presented by Rick Hicks of FDEP And Christy Crandall of USGS
STUDY OBJECTIVES • Identify significant nutrients and pesticides inputs to the Chipola River/Floridan aquifer system using existing information • Characterize the hydrologic and geochemical processes occurring along flowpaths using a groundwater flow and tracking model and a geochemical model along flow paths. • Test 1 or possibly 2 hypothetical scenarios—tracking nitrate and maybe an organic compound to the Jackson Blue Spring and the Chipola River. • Provide a model that will assist in predicting spring and ground water impacts from land use modifications
Study Area Location Chipola Watershed
Vertically contiguous thick sequence of limestone and dolostone of late Paleocene to early Miocene age Highly potable--drinking water is derived from Floridan aquifer system Contains numerous springs, sinks and other karst features—highly vulnerable. Floridan Aquifer System
The Floridan Aquifer and the Chipola River Basin • Recharge occurs mainly in unconfined and semi-confined areas • Potentiometric surface—flows southward from northern extent
The Floridan Aquifer and the Chipola River Basin • Ground water makes up the majority of the Chipola River's discharge during low and medium flow conditions • At least 63 springs identified(Barrios and Chellette, 2004)
Higher nitrate concentrations and more occurrances of nitrate and pesticides in the Chipola River and Floridan aquifer in this area than in other areas of the Floridan aquifer system (U.S. Geological Survey data).
2. Selected and sampled field parameters, NO3, and E.Coli at contributing springs and in the Chipola River (57 sites total sampled)
Preliminary Nitrate Results in mg/L as N
Preliminary E.Coli. Results In count per 100 ml
3. Used preliminary data to target 3 flowpaths and obtained permission to sample wells within these flowpaths: -2 flowpaths were selected for nutrient issues - 1 flowpath was selected for E.Coli
4 ) Sampled 3 wells along each flowpath for major ions, nutrients, age tracers, isotopes, pesticides, pharmaceuticals, field parameters
The 3 Selected Flowpaths With preliminary NO3 in mg/L as N From all data and networks -most flowpath data is not back from the lab yet.
4. Continue to build and calibrate a ground-water flow and particle-tracking model for the Floridan Aquifer/Chipola River system—progress
Existing Finite Element Ground-water Flow Model Boundaries (2) Tallahassee New MODFLOW based Ground-water Flow Model Boundary
GW Flow Model is built in MODLFOW using the following data and parameters from Finite element Model: • Hydraulic parameters • Aquifer tops and bottoms • Pumping data • Recharge • Boundary conditions • River stage and parameters • Starting heads
Model Currently running in MODLFOW but still needs work: • Boundary conditions are not working properly yet. • Currently working on this as Rick is giving this talk. • Will have to adjust parameters from old model during calibration.
Timetable • Model calibration completed by 12/07 • Particle tracking along flowpaths hopefully completed by 03/08