tm 8: watershed management and protection · proper siting of new water sources to minimize...

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 TM‐8:  Watershed Management and Protection  

1.0  Introduction Anapprovedsourcewaterassessmentandprotectionplan(SWAP)providesmultiplebenefitstoboththedrinkingwaterutilityandthecommunityingeneral.Thoughchangesinwaterqualityinawatershedaretypicallyslow,itmaybepossibletoimprovewaterqualitythroughexecutionofmanagementandeducationalstrategies.Sourcewaterqualitydirectlyimpactstreatmentprocessrequirements,regulatorycomplianceandtreatmentcosts.Therefore,improvementsinsourcewaterqualityarebeneficialtothedrinkingwatersystemandcanalsoprovideaestheticimprovementsforcommunitiesalonglakesandDetroitRiver.

ThistechnicalmemorandumdiscussestheUnitedStatesEnvironmentalProtectionAgency(EPA)andMichiganDepartmentofEnvironmentalQuality(MDEQ)requirementsandrecommendationsregardingsourcewaterassessmentandprotection.TheSourceWaterAssessmentProgram(SWAP)andSurfaceWaterIntakeProtectionProgram(SWIPP)aredescribedandcurrentDWSDreportsassessed.RulesspecifictotheGreatLakesarepresented.SinceportionsofthesourcewaterareasandoneoftheDWSDintakesareinCanadianwaters,theOntariosourcewaterprotectionprogramisreviewed.Theregulatorysectionconcludeswithalookatpotentialfutureregulations.

Sourcewaterqualityisdiscussedspecificallyasitmaybeimpactedbyclimatechange,bytheintroductionofzebramusselsandbyspills.GiventhattheLakeHurontoLakeSt.ClairtoDetroitRiverisamajorshippingchannelandshorelinemanufacturinglocation,detailsregardingspillsarediscussed.ThistechnicalmemorandumdiscussestheHurontoErieWaterQualityMonitoringSystem.Thisisamulti‐communitynetworkofwaterqualitymonitorsdevelopedspecificallytodetectspillsandothercontaminationevents.Finalrecommendationsarepresentedforimprovementstotheoverallsourcewaterassessmentandprotectionprogram.

2.0  Source Water Assessment Program (SWAP) & Surface Water Intake Protection Program (SWIPP) 

TheMichiganDepartmentofNaturalResourcesandtheEnvironment(MDNRE,nowtheMDEQ)completedaSourceWaterAssessmentProgram(SWAP)asrequiredbythe1996reauthorizationoftheEPASafeDrinkingWaterAct(SDWA).TheseSDWAamendmentsrequiredthestatesto:

Delineatethesourcewaterassessmentarea

Conductaninventoryofpotentialsourcesofcontamination,includingspillassessment

Determinethesusceptibilityofthewatersupplytocontamination

Providepublicinformation;includingspecificlanguagethatmustbeincludedintheConsumerConfidenceReport

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AllDWSDintakeshaveapprovedSWAPsbytheMDEQin2004.DWSDobtainswaterfromthreesources:

LakeHuronwhichprovideswatertotheLakeHuronWaterTreatmentPlant(WTP)

BelleIsleintheDetroitRiverwhichprovideswatertoWaterWorksParkWTP,SpringwellsWTPandNortheastWTP

FightingIslandintheDetroitRiverwhichprovideswatertoSouthwestWTP

TheSurfaceWaterIntakeProtectionProgram(SWIPP)isprogramdevelopedbytheMDEQtoprovideguidancetocommunitiesaftertheSWAPhasbeencompleted.ASWIPPincludesthesamesevenelementsastheWellheadProjectionProgram:

Definitionofrolesanddutiesofgovernmentunitsandwatersupplyagencies

Designationofasourcewaterprotectionareaforeachwatersupplysource(basedontheMDEQ’sdefinedsourcewaterarea)

Identificationofpotentialcontaminantsources

Implementationofmanagementapproachesforprotectionofsourcewater,includingbutnotlimitedtoeducationalandregulatoryapproaches

Creationofcontingencyplansforpublicwatersupplysourcesincludingthelocationofalternatedrinkingwatersources(ContingencyplansarediscussedinTMNo.13EmergencyResponsePlan)

Propersitingofnewwatersourcestominimizepotentialcontamination

Encouragementofpublicparticipation

DWSDhasnotcompletednorobtainedanapprovedSWIPPforanyoftheintakes.

2.1  Existing SWAPs 

TheUSGS(UnitedStatesGeologicalSurvey),theMDEQandDWSDcompletedtheSWAPrequirementsfortheDWSDsystemin1999.SWAPswereapprovedbyMDEQin2004.ThecompletedSWAPsincludetheregulatoryrequiredinformationaswellassectionson:

RegulatoryReview

BackgroundontheDetroitwatersystem

Sourcewatergeologyandhydrology

Rawwaterqualityhistory

References

Glossary

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Rawsourceswereratedforsensitivityandsusceptibility.Sensitivityisanindicationofthenaturalprotectionaffordedthesourcewaterbyitsnaturalsetting.Susceptibilityisbasedonfactorswithinthesourcewaterprotectionareathatmayposearisktothewatersupply.Thesusceptibilityratingisbasedonfourfactors:

Thepresenceofpotentialcontaminantsourcesfromthecontaminantinventoryandthelikelihoodthatcontaminantswillbereleasedfromthosecontaminationsources

Thephysicalintegrityoftheintake

Thesensitivityofthenaturalsettings

Thepresenceofexistingorlikelycontaminationofthesourcewater

TheEPA(2006)notesthattherearemultiplemethodsfordevelopingasourcewaterprotectionarea.Theorderofincreasingaccuracyandsophisticationis:

Arbitraryfixedradius

Calculatedfixedradius

Fixedvariableshapes

Analyticalmethods(suchastheuniformflowequation)

Hydrogeologicmapping

Numericalfloworflow‐and‐transportcomputermodels

Withinthesourcewaterprotectionarea,asubcategoryknownastheCriticalAssessmentZone(CAZ)isdetermined.TheCAZisthe“areafromtheintakestructuretotheshorelineandinland”.Theareaincludesatriangularwatersurfaceandlandareaencompassedbyanarcfromtheendpointoftheshorelinedistanceoneithersiteoftheonshoreintakepielocation”(MDEQ,1999).However,intheanalysisoftheCAZfortheDWSDintakes,theMDEQhastakenasimplifiedapproachwherebytheCAZisbasedonacombinationofthedistancefromtheshoretotheintakeandthewaterdepthresultinginCAZsof1,000or2,000or3,000feet.

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2.1.1   Lake Huron Intake 

TheLakeHuronIntakeprovideswatertotheLakeHuronWTP.Thecriticalassessmentzone(CAZ)isshowninFigure2‐1.Forthisintake,theMDEQcalculatedtheCAZas1,000feetfromtheintake.

Figure2‐1:CriticalAssessmentZone,LakeHuronWaterIntake(SWAP,2004)Thepointandnon‐pointcontaminantsourcelocationsareshowninFigures2‐2and2‐3.AsummaryofthecontaminantsisprovidedinTable2‐1.Theassessmentidentifiesthefollowingpotentialcontaminants:

40listedsources,includingsolidwastesites,industrialfacilities,toxicreleaseinventoryandnationalpriorylistsites;19oftheseareinthesusceptiblearea

Urbanandagriculturalrunoff

Shipping

Themajorpotentialsourceofcontaminationwasshipping.NotethatCanadianlandandwateruseswerenotconsideredanimpactonthisintake.

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Figure2‐2:PotentialPoint‐SourceContaminantSources,LakeHuronIntakeSourceWaterProtectionArea(SWAP,2004)

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Figure2‐3:PotentialNon‐Point‐SourceContaminantSources&SoilPermeability,LakeHuronIntakeSourceWaterProtectionArea(SWAP,2004)

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Table 2‐1:  Summary of Contaminant Sources for Lake Huron Intake (SWAP, 2004) 

Type of Potential Contaminant Source 

Number of Potential 

Contaminant Sources 

PCS within the Susceptible Area and 

the CAZ Hazardous or Solid Waste Site  22 10 Industrial Facilities Discharge Site 10 6 National Priority List Sites  0 0 Permit Compliance System  5 2 Toxic Release Inventory  3 1 Canadian Wastewater Treatment Facilities 0 0 National Pollutant Release Inventory  0 0 

ThisLakeHuronsourcewaterwasratedasmoderatesensitivityandmoderatelylowsusceptibilitybasedonthelimitednumberofpotentialcontaminantsources.

2.1.2  Fighting Island Intake 

TheFightingIslandIntakeprovideswatertotheSouthwestWTP.TheCAZisshowninFigure2‐4.TheCAZforthisintakeextends2,000feet.Thepointandnon‐pointcontaminantsourcelocationsareshowninFigures2‐5and2‐6.

Figure2‐4:CriticalAssessmentZone,FightingIslandWaterIntake(SWAP,2004)