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Is There a Groundwater Quality Is There a Groundwater Quality Problem?Problem?
• U.S. Geological Survey, IN Dept of U.S. Geological Survey, IN Dept of Environmental Management, USEPA, and Environmental Management, USEPA, and IN Dept of Natural Resources assembled IN Dept of Natural Resources assembled groundwater quality databasegroundwater quality database
• 18 pesticides and 5 “breakdown products” 18 pesticides and 5 “breakdown products” detected in 9% of samplesdetected in 9% of samples
Is There a Groundwater Quality Is There a Groundwater Quality Problem?Problem?
• Pesticides detected most oftenPesticides detected most often
– alachlor, atrazine, atrazine metabolitesalachlor, atrazine, atrazine metabolites
– di-ethylatrazine, di-isopropylatrazinedi-ethylatrazine, di-isopropylatrazine
– dicamba, 2,4-D, metolachlordicamba, 2,4-D, metolachlor
• Nitrate above 2 ppm in 50% of sampled Nitrate above 2 ppm in 50% of sampled wellswells
State Groundwater Management State Groundwater Management Plan - PresentPlan - Present
• Applies to pesticidesApplies to pesticides
• Education/OutreachEducation/Outreach
• Best management practicesBest management practices
• Sampling wellsSampling wells
State Groundwater Management State Groundwater Management Plan - Future?Plan - Future?
• Necessary regulatory management Necessary regulatory management approachesapproaches
• Restrictions on pesticide product use Restrictions on pesticide product use where neededwhere needed
DRASTICDRASTIC
DDepth to water tableepth to water table
RRecharge (aquifer)echarge (aquifer)
AAquifer mediaquifer media
SSoil mediaoil media
TTopography (slope)opography (slope)
IImpact of vadose zonempact of vadose zone
CConductivity (hydraulic)onductivity (hydraulic)
DRASTICDRASTIC
• Expert/numerical ranking modelExpert/numerical ranking model
• DRASTIC IndexDRASTIC Index
DDrrDDww + R + RrrRRww + A + ArrAAw w + S+ SrrSSw w + T+ TrrTTww + I + IrrIIw w + C+ CrrCCww
where r = Rating w = Weightwhere r = Rating w = Weight
DRASTIC Ratings for Depth DRASTIC Ratings for Depth to Waterto Water
Water TableDepth (ft)
DRASTICRating
0-5 10
5-15 9
15-30 7
30-50 5
> 100 1
DRASTIC Factor DRASTIC Factor WeightsWeights
Depth to Water Table 5
Recharge 4
Aquifer Media 3
Soil Media 2
Topography 1
Impact of Vadose Zone 5
Conductivity (Hydraulic) 3
DRASTICDRASTIC
DDrrDDww + R + RrrRRww + A + ArrAAw w + S+ SrrSSw w + T+ TrrTTww + I + IrrIIw w + C+ CrrCCww
8 * 5 + 2 * 4 + 8 * 3 + 6 * 2 + 7 * 1 + 1 * 5 + 7 * 38 * 5 + 2 * 4 + 8 * 3 + 6 * 2 + 7 * 1 + 1 * 5 + 7 * 3 = 117= 117
Data SourcesData Sources
• NRCS State Soils Geographic NRCS State Soils Geographic Database (STATSGO)Database (STATSGO)• Scale 1:250,000Scale 1:250,000• Info attribute tablesInfo attribute tables
• USGS DEM and geologyUSGS DEM and geology
• IGS hydrogeologic unit mapsIGS hydrogeologic unit maps
• IDNR and IGS water depthsIDNR and IGS water depths
DRASTIC Rating DRASTIC Rating TableTable
Vulnerability Rating Range
Low 1-100
Moderate 101-140
High 141-200
Very High > 200
Groundwater Groundwater Vulnerability IssuesVulnerability Issues
• Based only on hydrogeologic factorsBased only on hydrogeologic factors
• Does not consider land uses, Does not consider land uses, management, pesticide propertiesmanagement, pesticide properties
• High or very high vulnerability rating does High or very high vulnerability rating does not mean pesticides will be present in not mean pesticides will be present in groundwatergroundwater
• Low rating does not mean pesticides will Low rating does not mean pesticides will not be presentnot be present
BenefBenefitsits
• Provides reasonable estimates of Provides reasonable estimates of groundwater vulnerabilitygroundwater vulnerability
• Protects groundwaterProtects groundwater
• Targets sites for educationTargets sites for education
• Provides foundation for state groundwater Provides foundation for state groundwater management planmanagement plan
• Offers cost savings while improving Offers cost savings while improving groundwater protectiongroundwater protection