Nutrient and Pesticide Accounting in the Chipola River/Floridan Aquifer System—Update Presented by…

Nutrient and Pesticide Accounting Nutrient and Pesticide Accounting in the Chipola River/Floridan in the Chipola River/Floridan

Aquifer System—UpdateAquifer System—Update

Presented by Rick Hicks of FDEP

And Christy Crandall of USGS

This Study Jointly Funded by U.S. Geological Survey

and Florida Department of Environmental Protection

STUDY OBJECTIVESSTUDY OBJECTIVES

• Identify significant nutrients and pesticides inputs to the Chipola Identify significant nutrients and pesticides inputs to the Chipola River/Floridan aquifer system using existing informationRiver/Floridan aquifer system using existing information

• Characterize the hydrologic and geochemical processes occurring along Characterize the hydrologic and geochemical processes occurring along flowpaths using a groundwater flow and tracking model and a flowpaths using a groundwater flow and tracking model and a geochemical model along flow paths. geochemical model along flow paths.

• Test 1 or possibly 2 hypothetical scenarios—tracking nitrate and maybe Test 1 or possibly 2 hypothetical scenarios—tracking nitrate and maybe an organic compound to the Jackson Blue Spring and the Chipola River.an organic compound to the Jackson Blue Spring and the Chipola River.

• Provide a model that will assist in predicting spring and ground water Provide a model that will assist in predicting spring and ground water impacts from land use modificationsimpacts from land use modifications

BACKGROUNDBACKGROUND

Chipola Watershed

Study Area Location

• Vertically contiguous thick sequence of Vertically contiguous thick sequence of limestone and dolostone of late limestone and dolostone of late Paleocene to early Miocene agePaleocene to early Miocene age

• Highly potable--drinking water is derived Highly potable--drinking water is derived from Floridan aquifer systemfrom Floridan aquifer system

• Contains numerous springs, sinks and Contains numerous springs, sinks and other karst features—highly vulnerable.other karst features—highly vulnerable.

Floridan Aquifer SystemFloridan 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

• 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)

The Floridan Aquifer and the Chipola River Basin

• Higher nitrate concentrations and more Higher nitrate concentrations and more occurrances of nitrate and pesticides in occurrances of nitrate and pesticides in the Chipola River and Floridan aquifer in the Chipola River and Floridan aquifer in this area than in other areas of the this area than in other areas of the Floridan aquifer system (U.S. Geological Floridan aquifer system (U.S. Geological Survey data). Survey data).

Progress

1) Acquired and compiled existing data

2. Selected and sampled field 2. Selected and sampled field parameters, NOparameters, NO33, and E.Coli at , and E.Coli at contributing springs and in the contributing springs and in the

Chipola River (57 sites total Chipola River (57 sites total sampled)sampled)

PreliminaryNitrateResults inmg/L as N

PreliminaryE.Coli.ResultsIn count per 100 ml

3. Used preliminary data to target 3 3. Used preliminary data to target 3 flowpaths and obtained permission to flowpaths and obtained permission to sample wells within these flowpaths:sample wells within these flowpaths:-2 flowpaths were selected for -2 flowpaths were selected for nutrient issuesnutrient issues- 1 flowpath was selected for E.Coli - 1 flowpath was selected for E.Coli

4 ) Sampled 3 wells along each 4 ) Sampled 3 wells along each flowpath for major ions, nutrients, flowpath for major ions, nutrients, age tracers, isotopes, pesticides, age tracers, isotopes, pesticides, pharmaceuticals, field parameterspharmaceuticals, 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 4. Continue to build and calibrate a ground-water flow and particle-ground-water flow and particle-tracking model for the Floridan tracking model for the Floridan Aquifer/Chipola River systemAquifer/Chipola River system

—progress—progress

¹

0 20 4010 Kilometers

Legendflurbspol polygon

boundary

meshcl2_polygon

modgrid1_polygon

fldnext_84 arc

Existing Finite Element Ground-water Flow Model Boundaries (2)

TallahasseeNew MODFLOW based Ground-water Flow ModelBoundary

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 Boundary conditions are not working properly yet.properly yet.

• Currently working on this as Rick is giving Currently working on this as Rick is giving this talk.this talk.

• Will have to adjust parameters from old Will have to adjust parameters from old model during calibration.model during calibration.

TimetableTimetable

• Model calibration completed by 12/07Model calibration completed by 12/07• Particle tracking along flowpaths hopefully Particle tracking along flowpaths hopefully

completed by 03/08completed by 03/08