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

Aquifer SystemAquifer System

By Christy Crandall

A New Study Jointly Funded by U.S. Geological Survey

and Florida Department of Environmental Protection

New Joint Project between FDEP New Joint Project between FDEP and U.S. Geological Surveyand U.S. Geological Survey

• Scheduled to start in January but all of the Scheduled to start in January but all of the papers are still being signedpapers are still being signed

• Hope to start next monthHope to start next month

STUDY OBJECTIVESSTUDY OBJECTIVES

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

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

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

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

Why are we worried?Why are we worried?

• 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).

Concentrations were highest in ACFB

Network MedianNO3

ACFB 2.46SANT 0.05 GAFL2 0.54

GAFL3 0.05

GAFL4 0.06

Groundwater Nitrate

ACF Basin pesticide detections in wells & springs

Num

ber

of D

ecte

ctio

nsN

umbe

r of

Dec

tect

ions

FDEP Basin Status Report2002

Summary of SW Nutrients and Summary of SW Nutrients and Pesticides from 1995, USGSPesticides from 1995, USGSCowarts Creek nr. Cottonwood AL

Median nitrate concentration 0.5 mg/L as NNitrogen, Ammonia + Organic, Dissolved 0.25 mg/L as NPhosphorus, Total 0.03 mg/L as PMetolachlor 0.03 ug/LAtrazine 0.02 ug/L

Chipola River near Altha, FL

Median nitrate concentration 0.5 mg/LNitrogen, Ammonia + Organic, Dissolved 0.25 mg/L as NPhosphorus, Total 0.03 mg/L as PMetolachlor 0.05 ug/L

APPROACH

1. Acquire and compile existing dataWater Quality Data

FDEPUSGSNWFWMD

Land use

Aquifer Vulnerability

Potentiometric Surface

Stream

Aquifer Thickness

Maps

Pop

ulat

ion

in 2

005

Population Data

0

10000

20000

30000

40000

50000

60000

70000

80000

90000

1970 1980 1990 2000

Houston County (Ala)

Calhoun County

Jackson County

City of Marianna

2. Use data to target top 30 source 2. Use data to target top 30 source areas for nutrients and perform areas for nutrients and perform reconnaissance field sampling.reconnaissance field sampling.

Field ParametersField ParametersNitrateNitrate

BacteriaBacteriaFew Pesticides?Few Pesticides?

3. Use new data to target 10 most 3. Use new data to target 10 most significant source areas of significant source areas of nutrients and sample--analyses nutrients and sample--analyses to include major ions, trace to include major ions, trace elements?, age tracers, isotopes, elements?, age tracers, isotopes, pesticides, etc.,.pesticides, etc.,.

4. During this time a ground-water 4. During this time a ground-water flow and particle-tracking model will flow and particle-tracking model will be compiled and calibrated for the be compiled and calibrated for the

Floridan/Chipola aquifer/river Floridan/Chipola aquifer/river systemsystem

Start with existing Recent ModelsStart with existing Recent Models

Lyn TorakUSGS, Atlanta

Hal Davis USGS, Tallahassee

5. Track particles along flow lines 5. Track particles along flow lines and identify geochemical and identify geochemical processes occurring along processes occurring along flowpaths. flowpaths.

Flowpaths to a Public Supply Well

6. Use the model to test hypothetical 6. Use the model to test hypothetical scenarios such as:scenarios such as:– the effects of changing BMPs the effects of changing BMPs – or zoning changes on predicted or zoning changes on predicted

concetrations to the Chipola River concetrations to the Chipola River and Blue Springs and Blue Springs (3 to 5 locations).(3 to 5 locations).

Summary and ConclusionsSummary and Conclusions• New USGS MODFLOW CONDUIT FLOW New USGS MODFLOW CONDUIT FLOW

PACKAGE can switch between laminar and PACKAGE can switch between laminar and turbulent flowturbulent flow

• Project ends in 2009—I am hopeful that I may:Project ends in 2009—I am hopeful that I may:– be able to provide some insight on travel time from be able to provide some insight on travel time from

aquifer recharge to riveraquifer recharge to river– identify some major source areas and vulnerable identify some major source areas and vulnerable

areas areas – and potentially say something about land use and potentially say something about land use

protection.protection.