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Wellhead Protection and Land-Use By Judy Muehl Pennsylvania Rural Water Association
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Quantifiable costs –Treatment –Pollution clean-up –Litigation? –Loss of property value and tax revenue Less quantifiable costs – health costs from exposure It’s Cheaper to Prevent Contamination
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Insects Small mammals Surface water Groundwater Flow Barnyard, yards, dumps, mines, septic systems, etc. Aquifer Contamination Well Head Contamination Contamination Can be Local or Widespread soil Bedrock Aquifer
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X Keep activities at least 50 feet or more from wellhead or spring box Water Supply Protection Starts at Home! Septic systems Driveways Fertilizer Pesticides
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Publicize Household Hazardous Waste Collection Programs Dispose of Household Chemicals Properly
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Properly Locate the Water Supply Wellhead protection zones well home and septic system stream barn and barnyard Greatest impact on well Moderate impact on well Some impact on well Direction of Groundwater Movement
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Wellhead Protection Area A minimum of 50 feet in every direction Preferably more than 50 feet upgradient from the well Why 50 feet? –That’s the active recharge area for a typical home well producing 200 gallons per day.
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Wellhead Protection Zones for Public Water Supplies Red = sources of potential contamination Zone III Zone II Capture Zone Zone I 100 - 400 Ft Where is the water that needs protection? Zone II + Zone III = Area of Contribution
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Coliform Bacteria “Indicator” organisms Indicate the “potential” for disease-causing bacteria E. coli is an example One of the most common problems in wells and springs Occur in about 50% of private water systems Can enter wells and springs from surface runoff, human/animal waste, insects, etc. May occur from poor construction or aquifer contamination
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Seal the spring box to prevent insects, animals and surface contamination
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Sanitary well cap Grout seal Good casing Sloping Ground Soil Bedrock Groundwater “aquifer” Water Table Proper Construction Can Prevent Wellhead Contamination
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Photo by Tom McCarty Don’t Get Carried Away !
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Grouting Reduces Bacterial Contamination % Contaminated (Zimmerman et al., 2002)
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Standard Well CapSanitary Well Cap Approximately 50% of private wells had obvious insect activity under cap 15% of wells with total coliform bacteria could be solved by installing a sanitary well cap. Sanitary Well Caps Also Help
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Even a Perfect Well Can Have Bacteria
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Agricultural Acid Mine Drainage Commerce/ Industry Residences Waste Management Stormwater Runoff Larger Scale Groundwater Contamination
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Groundwater Moves !
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Common Naturally Occurring Problems in PA Groundwater White residue, dull laundry – hardness –42% of wells and springs have hard water > 180 mg/L –Especially in carbonate (limestone) areas Reddish stains, metallic taste – iron –Common in sandstone / shale aquifers Black stains, metallic taste - manganese –Often occurs with iron Rotten egg odor - hydrogen sulfide gas –Very common in wells in certain shale formations Blue stains, metallic taste - corrosive water –Generally caused by low pH and soft water
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Corrosivity and Low pH Region of PA Percent Not Meeting Standard
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Natural Problems Can Cause Other Pollutants Region of PA Lead in Private Water Supplies Based on 1,600 samples Comes mostly from corrosion of plumbing High correlation between blue stains, metallic taste and lead Percent Above 15 ppb
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Land Use Impacts Groundwater Industry Organics, Petroleum Agriculture Bacteria, Nitrate, Pesticides Mining Metals, pH Landfills Organics, ? Roads Chloride, Sodium Houses Bacteria Nitrate Sediment Yard Chemicals
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Water Testing Should Target Local Land Uses MiningIron, Manganese, pH AgricultureNitrate, bacteria, pesticides HousesBacteria, nitrate Gas / oil wellsPetroleum, sodium, chloride RoadsSodium, chloride Dumps, industryOrganic scans Routine water testing PRIOR to activities is important to document water quality and may provide some legal protection !
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How Close do Activities Need to Be? In general, homeowners should be concerned about activities that are visible from their home In limestone or gravel aquifers, activities further from the home could be important
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Example of Land Use Impact Average Nitrate-N (mg/L) 1,600 private water supplies in PA
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Occurrence of Nitrate in Private Water Supplies Percent Above 10 mg/L Nitrate most often occurs with intensive agriculture Region of PA
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Iron and Sulfate in Private Water Supplies Percent Above Standard Iron and sulfate are most prevalent in coal mining regions Region of PA
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Other Health-Related Pollutants Giardia and Cryptosporidium –Protozoans common in surface water –Very rare in wells and springs Volatile Organic Compounds (VOC’s) –Around industrials sites, gas stations, urban areas, etc. –Examples – benzene, PCE, TCE, toluene –Widespread in some areas, especially SE Pennsylvania Pesticides –Occur in <5% of wells and springs that have been tested –Atrazine is the most common pesticide detected
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Reduces infiltration through compaction (yards) or pavement (roads, sidewalks, driveways) causing less recharge of groundwater Homes with wells and public sewer may remove water from the aquifer Sprawl moves water use from cities to suburban or rural areas = more users in traditionally rural areas Groundwater mining may occur = more withdrawal than recharge Common misconception is that homowner owns water under their property Land Use Can Also Affect Water Quantity
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Abandoned Wells Photo: Purdue Extension Service May serve as a pathway for future contamination of groundwater Should be plugged by a licensed well driller Graphic: North Dakota State Univ.
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Homeowner Actions Practice local wellhead protection on their property Be aware of current and proposed land use surrounding their property Test water annually for pollutants associated with current or proposed land uses
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