RESOURCES TO HELP YOU PROTECT YOUR DRINKING WATER SUPPLY

COMPREHENSIVE PLANNING AND GROUNDWATER FACT SHEET 2GROUNDWATER COORDINATING COUNCIL

July 2002 (Revised February 2005)

Over 95% of Wisconsin’s communities and about 75% of Wisconsin residents rely on groundwater for theirdrinking water supply. In addition, groundwater is used widely by agriculture and industry. Groundwater alsorecharges Wisconsin’s lakes, rivers, streams and wetlands, maintaining the vitality of the entire ecosystem. In orderto plan for the future, it is important that you consider both the quantity and quality of groundwater available to yourcommunity. The future of your community depends on having a safe and dependable supply of groundwater. Howdo you find out about your groundwater resources? Through a series of questions, this fact sheet describes whatinformation you’ll need to address groundwater in your comprehensive (“Smart Growth”) plan and where to go tofind that information.

Where does your community’s groundwatercome from?It is important to identify both the geologicmaterials or the geologic setting from whichyour community’s groundwater comes and therecharge area which contributes water to yourwell(s).

What geologic materials provide water for yourcommunity’s well(s)?� Your local water utility should have

engineering reports or wellhead protectionplans for each of your well(s). These plansdescribe local geologic and groundwaterconditions in the area around yourcommunity’s well(s). These reports canprovide information on the geologicmaterials in your area and which water-bearing formation or formations (aquifers)provide groundwater to your well(s).

� Another source oflocal geologic andgroundwater information isthe Wisconsin Geologicaland Natural History Survey(WGNHS). The WGNHSmay have reports ofgeologic and/orgroundwater conditions inyour county. You can

view the WGNHS List of Publicationsonline at:http://www.uwex.edu/wgnhs/pubs.htm orget a copy by calling 608-263-7839.

� The WGNHS also maintains records ofwells drilled in the state. Find out aboutgetting copies of well records by goingonline at

http://www.uwex.edu/wgnhs/well.htm or bycalling Irene Lippelt at 608-262-7430.

� Well construction reports can also beobtained online at the WisconsinDepartment of Natural Resources (WDNRs)Drinking Water System page at:http://dnr.wi.gov/org/water/dwg/dws.htm.

� The WDNR completed source waterassessments for all public water systemsbetween 2001 and 2004. These assessmentsinclude a summary of geologic and wellconstruction information for each systemand were hand-delivered to each waterutility.

� As part of the source water assessmentprocess, groundwater modeling wasconducted to assist in source water areadelineations in highly populated areas.These areas included: the SoutheasternWisconsin Regional Planning Commissioncounties plus Dane, Eau Claire, Fond duLac, LaCrosse, Pierce, Rock, St. Croix andSauk Counties. Computer models were alsoused for the Central Sands and the LowerFox River Valley which incorporate parts ofAdams, Juneau, Marquette, Portage,Waushara, Brown, Calumet, Outagamie andWinnebago Counties. See the WDNRwellhead protection website athttp://dnr.wi.gov/org/water/dwg/gw/wellhead.htm for a map and contact information forthese regional hydrologic studies whichcontain detailed geologic and groundwaterinformation.

What land area contributes recharge to yourcommunity’s well(s)?It’s also important to identify the land areacontributing water to your well through

infiltration of precipitation into the subsurface.Rain and snow seep into the ground and migratethrough the soil to groundwater, which thenflows toward your well(s). This area, known asthe recharge area, can also allow contaminants to

enter the subsurface. If anunderground storage tank or alandfill leaks contaminantsinto the ground within therecharge area, thesecontaminants could reachyour community’s well.

� Your water utility may have identified therecharge area for your well(s) as part of awellhead protection plan or other report. Ifyour community doesn’t have a wellheadprotection plan, you can identify therecharge area by one of several methodsoutlined in the WDNR publication “ATemplate for Preparing Wellhead ProtectionPlans for Municipal Wells”, PUBL DG-053-00. It is available for downloading off theWDNRs wellhead protection website athttp://dnr.wi.gov/org/water/dwg/gw/whp/WHPtplat.pdf or by calling Dave Lindorff at608-266-9265.

� The source water assessments describedabove identified each well’s 5-year time oftravel (TOT) capture zone for each publicwater supply well, that is the area whichcontributes recharge to the well over 5 years.These source water assessment areas weredetermined by the groundwater modelingdescribed above, a wellhead protectiondelineation if one has been done or a simplecalculation with a default circle with aradius of 1200 feet around the well. Thedelineations were included in theassessments given municipal water utilitiesin 2003 and 2004.

Are there sensitive areas within the rechargearea that warrant protection or specialconsideration?As you gather information for your community,it is important to identify any areas that mayneed some special consideration. For example,there may be areas that because of soil type,geologic features, shallow depth to the watertable or other reasons are sensitive tocontamination. There may be critical portions ofthe recharge area for your wells that need to beprotected to maintain adequate recharge. Theremay be areas where poor groundwater quality orlimited groundwater availability makes itunsuitable for development of private wells.

� The 2002 publication, “Planning for NaturalResources”, identifies a variety of sourcesfor natural resource information that isavailable from the WDNR and othersources. It lists contact information forwetlands, floodplains, geology, soils,contaminated sites and other naturalresources. The publication is available fromCounty Extension offices, the Department ofAdministration’s Office of Land InformationServices (608-267-2707) and athttp://dnr.wi.gov/org/es/science/landuse/smart_growth/index.htm#planbook.

� The WGNHS may have geologic andgroundwater maps for your area that identifyparticularly sensitive geologic areas.

� Your community, water utility, county or thelocal Regional Planning Commission mayhave information on sensitive areas thathave been identified.

� If computer groundwater models have beendeveloped for source water assessments orother purposes, it may be possible to usethem to predict the impacts of variousdevelopment scenarios. For example,groundwater models could be used toidentify the impacts of additional wells ornew development. Use of a groundwatermodel should be undertaken with theassistance of a groundwater professionalwho can help you understand the uses andlimitations of the model.

How much groundwater do your wellscurrently produce?As you plan for the future, it is important tounderstand the current capabilities of your watersupply system so you can determine what yourcommunity will require to meet future needs.� Your local water utility should have

historical pumping records for each of yourwells. Water utilities are also required tosubmit monthly pumping records to theWDNRs Bureau of Drinking Water andGroundwater. Using data from thosemonths when water use is highest (typicallysummer), you can calculate a worst caseaverage daily use per person.

� Your local water utility should be able tolook at current use compared to wellcapacity to determine how close your wellsystem is to capacity. If it is near capacity,then a new well may be needed soon. Usingpump capacity data from your wells toestimate long-term well productivity can

give an inaccurate assessment since mostpumps aren’t designed to work continuouslyat their maximum capacity. It is alsoimportant to remember that, if your wells areclose together, increased pumping by one ofthe wells may cause interference with (andlower yields from) your other wells if theywithdraw water from the same aquifer. Thisincreased pumping may impact other nearbywells, e. g. industrial wells or private wells.

What are the existing and potentialcontaminant sources that could impact yourwells?In order to protect your water supply, it isimportant to know if there are any contaminantsources within the recharge area of your well thatmight contaminate your well. This wouldinclude any known sources of contamination aswell as potential threats to your wells. Figure 1shows some potential contaminant sources.� For the source water assessments described

above, the WDNR developed a geographicinformation system (GIS) database withcontaminant sources identified from some ofthe databases listed above. From this GISdatabase and other information, mapsshowing potential contaminant sources forall public water supply wells were includedin the source water assessments given towater utilities in 2003 and 2004.

� Your water utility should have completed acontaminant source inventory either for awellhead protection plan or for avulnerability assessment to justify a waiverfrom water quality monitoring requirements.If a contaminant source inventory hasn’tbeen completed for the recharge area aroundyour wells, you can download a copy of “AGuide for Conducting Potential ContaminantSource Inventories for Wellhead Protection”from the WDNRs website athttp://dnr.wi.gov/org/water/dwg/gw/whp/ContamSI.pdf or by calling David Lindorff at608-266-9265.

� Another source of potential contaminantsource information is the WDNRpublication “Directory of GroundwaterDatabases”. It identifies a number ofdatabases that contain information onpotential contaminant sources. It isavailable for downloading athttp://dnr.wi.gov/org/water/dwg/gw/pubs/directory.pdf or by calling David Lindorff at608-266-9265.

� A summary of contaminant source inventoryresources on the web is available athttp://dnr.wi.gov/org/water/dwg/gw/whp/Whpnews6.pdf.

� The WDNRs Bureau of Remediation andRedevelopment’s Tracking System(BRRTS) is the program’s main database fortracking contaminated properties. It can beaccessed on the web athttp://dnr.wi.gov/org/aw/rr/brrts. TheBureau also maintains the GIS Registry ofClosed Remediation Sites at:http://gomapout.dnr.state.wi.us/org/at/et/geo/gwur/index.htm.

� The Department of Agriculture, Trade andConsumer Protection website(http://datcp.state.wi.us/arm/agriculture/pest-fert/pesticides/atrazine/index.html) containsmaps of atrazine prohibition areas in thestate. Contact the Agriculture ChemicalCleanup Program(http://datcp.state.wi.us/arm/agriculture/pest-fert/pesticides/accp/contact.html) regardingthe location of sites contaminated bystorage, handling or spillage of agriculturalchemicals.

� The Department of Commerce undergroundstorage tank database is located at:http://www.commerce.state.wi.us/ER/ER-EN-tanks-info.html.

Figure 1. Some potential contaminant sourcesof groundwater and water supply wells.

Does the quality of the groundwater fromyour wells meet drinking water standards?In order to plan for the future, you need tounderstand whether there are any problems withyour current water quality that need to beaddressed.

� Your water utility is required to sample itswells to make sure its groundwater qualitycomplies with drinking water standards.Checking its records can determine if thereare any existing contamination problems.All public water supply systems are requiredto submit to their customers a ConsumerConfidence Report (CCR) by July first ofeach year that describes the quality of thewater it is providing. Your water utilityshould have a copy of the most recent aswell as past CCRs.

� It is also important to check the historicalrecord of sampling results for each wellback to when it was installed. Thisinformation can be valuable to determine ifthere are any trends of increasingcontaminant concentrations that might notbe apparent from a cursory data evaluation.This can be an important planningconsideration if a new well is needed toaddress a contamination problem.

� Your water utility is required to providesampling results to the WDNRs Bureau ofDrinking Water and Groundwater. Thisinformation can be found for your utility athttp://dnr.wi.gov/org/water/dwg/dws.htm.

Answering the above questions can provide aframework for planning for water supplyprotection. Using the above information, youcan make informed decisions to make sure yourwater supply is protected for the future. Inconjunction with other information, you canassess how much water you will need in thefuture and where that water will come from.Will additional wells be needed and, if so, whereshould they be located to minimize potentialcontamination problems?

Wellhead protection/source water protectionOne of the ways that communitiescan protect their watersupply is throughwellhead protectionplanning. Throughthis program, acommunity canidentify the recharge area for its well or wells,inventory potential contaminant sources withinthat area and take steps to manage that area toprotect its wells from contamination.

In an effort to assist communities in theirwellhead protection efforts, the WDNR preparedsource water assessments for all public watersupply systems in the state. This effort wasrequired by the 1996 Amendments to the SafeDrinking Water Act. Each assessment contains amap showing the source water assessment areafor each public water supply well or surfacewater source and the potential contaminantsources within the source water assessment area.The assessment also contains a determination ofthe susceptibility of each well or intake tocontamination. The WDNR will work withcommunities to use the source water assessmentinformation to develop a wellhead protectionplan. Summaries of each assessment areavailable at the WDNR source water assessmentwebsite athttp://dnr.wi.gov/org/water/dwg/swap/index.htmor call Jeff Helmuth at 608-266-5234 for moreinformation.

For more information on Wisconsin’s wellheadprotection program or assistance with wellheadprotection planning, visit the WDNR website athttp://dnr.wi.gov/org/water/dwg/gw/wellhead.htm or call Dave Lindorff at 608-266-9265.

This is one of a series of groundwater factsheets designed to provide information to assistcommunities with comprehensive planning. Other factsheets and more detailed information to assist

planners can be found at the Groundwater Coordinating Council (GCC) web site,http://dnr.wi.gov/org/water/dwg/gcc/ or the WDNR Land Use Team website at

http://dnr.wi.gov/org/es/science/landuse/index.htm.Acknowledgments: Illustration, page 3 from WDNR publication WR 312-92 Determining WellheadProtection Boundaries – An Introduction.

Comprehensive Planning and Groundwater Fact Sheets were produced by GCC subcommitteemembers Dave Lindorff, WI Department of Natural Resources; Chris Mechenich, Central WIGroundwater Center; and Chuck Warzecha, WI Department of Health and Family Services.

July 2002 (Revised February 2005)