MONTANASTATELIBRARY , S628.16832U24wspu1991C.1 WarmSpringsPondsupdate:SilverBowCr 3 0864 00073825 5 Silverbow ureeK/Bune Area SuperfiffiffiSitemms collection WARM SPRINGS PONDS -'"kilE* ____ MONTANA UPDATE LlSKjftJRY U.S. Environmental Protection Agency, Montana Office andthe Montana Department of Health & Environmental Sciences FOR HISTORYAND BACKGROUND OF WARM SPRINGS PONDS, REFERTO INSERT. SeparateRecord ofDecision ForPond 1 And Lower Area This Update Describes: The September 1990 Record of Decision for the Warm • LSoewpearraAtreeaRecord of Decision for Pond 1 and SpringsPondsdefersanactiondecisionfortheareanorth ofPond 1foroneyear.Partofthecomplexityinmakinga • Mill-WillowBypassRemovalAction decision for remediation of this lower area is that the •TreatmentCapabilitiesofPonds2&3 sahrsaelnliocwgarnoducnadwdamtieurmi.scoEnPtAawmainntastteodawsistuhrmeetthaalts,cpornitmaarmiil-y • HistoryandBackgroundofWarmSpringsPonds natedgroundwaterdoesnotentertheClarkForkRiveror descendtodeeperaquifers. Further,the contaminated ) taamiloinnggsatnhedmsoesdtimeexnttesnsiinvPeownitdhi1natnhdetphoendSoswyesrteamr.eaare CEPoAmphaasnyrec(eAiRvCeOd)afporrorpeodsuaclifnrgotmhtehegrAotulanndtwiactReirchfcioenl-d tamination and isolating the tailings and contaminated Thesefactors,togetherwithpublicinput,haveledEPAto soilswithinPond1andthelowerarea.ARCOhasproposed declarePond 1 andthelowerareaanewandseparate to chemically fix and wet-close (cover with water) the study area or operable unit. By doing so, a separate east half of Pond 1 and the contaminated area below Record of Decision is necessary. This enables EPA to Pond 1 (See Figure 1). Inthe proposed plan ofOctober progresswiththe remedial action described intheSep- 1989, the EPA and the Montana Department of Health tember 1990RecordofDecisionfortheotherportionsof and Environmental Sciences (MDHES) had proposed to the Warm Springs Ponds area. These active portions, dry-close(excavateandcoverwithsoil)allofPond1 and including Ponds 2 and 3 and most of the Mill-Willow remove about one-sixth of the tailings below Pond 1 bypass,will continue underthe original direction ofthe alongtheoldSilverBowCreekchannel. EPAwillbringall September 1990 Record of Decision. Work is being de- proposalstofullpublicreviewduringthefallof 1991. ferredonPond 1 andthelowerareauntiladecisioncan bemadewithfullpublicreview.Thedecisiontodividethe Mill-Willow Bypass Removal Action WarmSpringsPondsintotwoseparateunitsisdescribedin detail in theJune 1991 Explanation of Significant Differ- The original Mill-Willow bypass was constructed around ences. 1970 to divert the relatively clean water from Mill and Willowcreeks aroundthe pondsystem. Priortothat, Mill EPA ISSUES NOTICE TO andWillowcreeksjoinedSilverBowCreekjustabovethe BEGIN WORK presentlocationofPond3. Thebypasschannelbecame contaminatedwhentheinlettoPond3becameplugged On June 7, 1991, EPA issued a special notice to withrunoffdebris,causingSilverBowCreektoflowintothe ARCOto begin implementation ofthe remedy as bypass channel. This deposition of tailings along the described inthe September 1990Record of Deci- bypasshashappenedrepeatedlyoverthepast20years. sion, as modified bytheJune 1991 Explanation of Numerous fishkills occurred during that period, usually Significant Differences. All remedial activities will following summerthunderstorms which washed metals- takeplacewithEPAoversightandareanticipated bearingsaltsintothebypassstreamsandtheupperClark tobecompletewithintwotothreeyears. ForkRiver. FollowingaJuly1989thunderstorm,morethan jhu^njpjpqfeitheraquaticorgan- i CLARK isms were killed by exposure to heavy metals. These AREAOF RFIOVREKR fishkills prompted EPA and MDHES to initiate the Mill- PROPOSED WillowBypassRemovalAction. NEWRECORD OFDECISION ThetailingsremovalworkbeganinJulyof1990andwas mostlycompletebyNovemberof 1990. Theworkwas doneunderanAdministrativeOrderonConsentissued by EPA to ARCO. ARCO hired local contractors to performthework.IndividualsfromEPAandMDHESwere presentonadailybasisduringtheentireremovalaction. Waterandsoilsampleswereroutinelytakenthroughout OUTLETTO BYPASS the action. All of the engineering design work was carefully reviewed and approved ahead of time by EPAandMDHES. Atotalof436.000cubicyardsoftailingsandassociated WILDLIFE soils was removed from the 3.8-mile bypass channel. PONDS ^ EPAandMDHESfeelthattheremovalactionwassuc- cessfulinreturningthebypasschanneltonaturalmetals levels.Table 1 reflectstheimprovementofmetalscon- centrations in the bypass soils following the removal action. The tailings and contaminated soils were re- movedandplacedina25-acredryclosureareawithin Pond3. Allofthis materialwasplacedabovethewater levelbehindreinforcedberms,andcoveredwithlime- stoneandsoil.Theareawasplantedwithnativegrasses MILL-WILLOW inthespringof 1991. BYPASS- Inadditiontothetailingsremoval,thebermsbetween thebypassandthepondswereimproved. Theberms were raised,widened,and armoredto provide maxi- mumprotectionagainstearthquakesandfloods. Asci! cementarmor,9feetthick,wasappliedtothebypass sideofthe pondbermstohelppreventerosionduring severefloods. Thechannelhasbeengreatlyenlarged POND3 to allow passage of 70,000 cubic feet of water per ACRLEOASURE second (CFS), which is estimated to be one-halfthe probablemaximumfloodamount. Animportantcom- ponentoftheimprovedbypassisthatitwillbeableto containthewaterfromamajorfloodwithoutthreaten- "LIME TREATMENT TABLE FACILITY 1 AverageMetals ConcentrationsInSoils Pre-Removal, Post-Removaland Natural PartsPerMillion Pre- Post- Removal Removal Natural Arsenic 244 14.8 12-30 Cadmium 9 1.1 <1 Lead 238 16.3 12-20 Copper 2,758 64.7 20-50 COMPONENTSFiOguFreWA1 RMSPRINGS ;Zinc 1,996— 124.4 30-100 PONDSANDMILL-WILLOWBYPASS : rr: Warm Springs Ponds History and Background The Warm Springs Ponds are part of the Silver Bow unstable berms,fishkillsandtailingsthataresubjectto Creek/ButteAreaSuperfundSiteintheUpperClarkFork winderosion. BasinareaofMontana. Theycoverapproximately2500 acresandincludethreesettling ponds,thearea north TheEPA.inconsultationwithMDHES,producedaRecord of Pond 1 tothe Clark Fork River's beginning point, a ofDecisionontheWarmSpringsPondsinSeptemberof seriesofwildlifeponds,andthe Mill-Willowbypass. 1990whichidentifiedtheselectedremedyforcorrect- ingproblemsassociatedwiththeponds. TheRecordof From 1880untilthe 1970's,mining,millingandsmelting Decisionwaspreparedfollowingextensivepublicinput. wastes from the Butte and Anaconda areas were Ingeneral,the remedyincludesmeansfor; dumpeddirectlyintoSilverBowCreek. Earlyon,these wastesweretransporteddownstreamasfarasMilltown •Allowingthepondstocontinuetofunctionastreat- Reservoir,adistanceof145rivermiles. Alongthisentire ment ponds until upstreamsources ofcontamina- distance,tailingsandcontaminatedsedimentssettled tionareeliminated, outasfloodsreceded,creating"slickens".Thesemetals- bearing deposits are more numerous and expansive • Raising andstrengtheningthe pond bermstopro- alongSilverBowCreekthanalongtheClarkForkRiver; tectthemfromfailureduringfloodsandearthquakes, however,the riverstillsufferstodayfromtheeffectsof • Comprehensivelyupgradingthetreatment capa- thesedeposits. bilitiesofPonds2and3,and Beginning about 1911,the first pond was created on • RemovingtailingsfromtheMill-Willowbypass. Silver Bow Creek near the town of Warm Springs to controlthe amount ofsedimentcarried intothe Clark EPA and MDHES continueto strive to involve all inter- ForkRiver. Later,in 1916and 1959.Ponds2and3were ested parties. Public scoping meetings on the Mill- constructed. An estimated 19 million cubic yards of WillowBypassRemovalActionwereheldinFebruaryof sediments,tailingsandheavymetalsludgeshavebeen 1990. The agenciesheldfive morepublic meetings in collectedinthethreeponds. Inadditiontothismassive February and May of 1990 to gather input from the volume of contaminated material, other problems at public on the removal activities and other actions the pond include contaminated groundwater, peri- plannedbytheagenciesandARCO. Thepublicwillbe odicexceedencesofsurfacewaterqualitystandards. askedforinputonfutureactivitiesaswell. ^ urban BUIS J/VARM SPRINGS MISSOULA PONDS MILL-WILLOWBYPASS ,\ ADCn^DI C IIhiIT WARMSPRINGS^ creek ^XT- NOTTOSCALE PROJECT SITE- KEYMAP Digitized by the Internet Archive 2015 in https://archive.org/details/warmspringsponds1991unit . ing the stability ofeitherthe pond berms orthe tailings thisprocess,livingalgaeactonmetalsandabsorbthem. stored behindthem. Whenthealgaedie,theysettletothepondbottomand asludgeforms. Before the removal work of 1990 was complete, plans were underwayfor rehabilitatingthe area. Beginning in Animprovedtreatmentsystemwillbepartoftheremedy thesummerof1992,thebypasswillberevegetatedand fortheWarmSpringsPonds. Itwillincludealimedispensing reconfiguredtocreateameanderingstreamsystemwithin facilitylocatedattheinletsouthofPond3wherecarefully thechannel. Thebypassisexpectedtoprovideexcellent calculatedamountsoflimewillbeaddedtothewaterto troutandwaterfowl habitatwhen ARCO completesthis createthe properpH level. Treatedwaterwillberouted work. intoanenlargedPond2foradditionalbiologicaltreatment andretentiontime,thenoutofPond2intotheMill-Willow TOrwdoearmbeentdwmeeenntEsPhAavaendbeAeRnCOm,adeenatboltihnegAAdRmiCniOsttroatpirvoe- Wbiytphastsh.eTehxecedpitsicohnarogfetdhewaetmeerrwgilelnbceymsopniilltwoaryse,dAreRgCulOarwliyl.l ceedwithreinforcementworkontheeast-westbermsof berequiredtomeetstringentwaterqualitystandardsfor Ponds 2 and 3 and with improvements to flood control all discharge pointsfromthe ponds. Also,as partofthe structures. These activitieswill becompleted during the remedy,thetailingsinPond2willbewet-closed,meaning summerof 1991. thattheexposedtailingswillbeflooded,thuseliminating directcontactbyhumansorwildlife. Treatment Capabilities of Ponds 2 & 3 The effectivenessoftheWarmSprings Ponds as atreat- TheWarmSpringsPondshavebeensuccessfullycontain- mentsystemforremoving arsenicandheavymetalshas ing and treating water from Silver Bow Creek for many alreadybeenproven. Thefirstfewmilesofstreamimme- years. TheadditionofPond3in1959greatlyimprovedthe diatelybelowthepondsarecurrentlythemostproductive ponds'treatmentcapabilitieswiththeexceptionofthose troutandaquaticinvertebratehabitatintheentireupper occasionswhentheinletbecamepluggedandSilverBow ClarkForkRiver. Upto2000troutperrivermilehavebeen Creekfound itsway intothe bypass channel. Currently, counted during surveys. However, the number of trout thepondscanreceivenomorethan600CFSofwaterflow declinessharplytolessthan200-300perrivermilebetween fromSilverBowCreek. AlthoughtheaverageflowofSilver DeerLodgeandthemouthofRockCreekaboveMissoula. BowCreekisabout90CFS,springrunoffflowsareexpected Manyfactorsaccountforthisreduction,including irriga- i tWoheexncetheids o6c0c0uCrsF,Soarppwrhoexinmattheeliynloentcbeecevoemreysotphleurgygeeadr,. ttieomnpdeerwaatutreersi,nga,nbdantkhsedreegarcacudmeudlbaytiloivnesotfocmke,thailgshawsatteher Silver Bow Creek enters and contaminates the bypass waterflowsdownstream. Theselectedremedywillsignifi- channel. cantly improve the ponds' treatment capabilities, par- ticularlyathigherflowsandgreatervolumes. OncetheremedyfortheWarmSpringsPondsisinplace, Pond 3 will be able to receive up to 3,300 CFS and thereforehavetheabilitytotreatfloodwatersuptothe The following WarmSprings Ponds documents are §§ 100yearfloodamount. Thepondswillcontinuetofunc- availableforpublicreview: tionasatreatmentsystemforSilverBowCreekaslongas tBhoewreCirseuepks/tBurtetaemAcroenataSmuipneartfiounn.dSWitheeisnctlheeaneentdiruepSialnvedr • WCraeremkSSupprienrgfsunPdonSidtseRPerpooprto,seUdSEPPlAana,nSdilMveDrHBEoSw, |W|| allupstreamcontamination iscontrolled,thefate ofthe October, 1989. rpeotnadinesdy,sotretmhewiyllmabeybreeepxaratmiialnleydd.ewTaheterpoenddtsobmeacyombee •RNePcLorSidteo.fWDeacrismioSnp,rSiinlgvserPBoonwdCsreOepke/rBaubtlteeAUrnieta. | avastwetlandsarea. Inanycase,theywillalwaysserve UpperClarkForkRiverBasin,USEPA,September. asa “safetynet"evenafterremediesforButteandSilver 1990. BowCreekareinplace. Tbhoethwastuesrpternedaetdmesnetdoicmceunrtrsinagnidn Pdoinssdoslv2edanmdet3aalcststhoant • aClnadrkMDFoHrEkS.SuNpoevrfeumnbderS,ite1s99M0a.ster Plan, USEPA | cmoonvtailnuoafllcyoennttaemrinthaentpsofnrdosmftrhoemwSaitlveerr BisoawccCormepelki.shReed- •SAociltsiRone,mWoavramlSRperpionrgt,sMPiolln-dWiOlpleowrBaybplaesUsniRte,mWoavraml || sbeyttplhiynsgiacanld,cchheemmiiccaallatnrdeabtimoelnogtibcaelgipnrsocqeusisceksl.yTahsewianitteiarl SMparricnghs..1M9o9n1.tana,AtlanticRichfieldCompany, \'V\i enters Pond 3. A simple physical reduction of metals- bearingsolidsoccursthroughgravitationalsettlingofsedi- • Explanation of Significant Differences to the omxeindtesstinotrheeacptownidtsh.mAetaclhse,mcirceaaltilnigmesotlrueblaetmpernetcipciatuasteess SSperpitngesmbPeornd1s99O0pReercaobrldeofUnDiet,ciJsuinoen,fo1r9t9h1eWarm y thatremovethedissolvedmetalsfromthewater. Finally, biologicalprocessesactasafinishingtreatment. During b Tinhfeorpmraetviioonusrelpiosstietdordioesc:uments can be found at these ForturtherinformationregardingtheWarmSprings Ponds,contactthefollowing individuals: • MontanaTechlibrary/Butte WestParkStreet : • B1u0t6teW-eSisltveBrrBooawdwLiabyrary/Butte UPSaEmPAH,ilMleoryntoraSncaotOtffBircoewn • Grant-KohrsRanchOffice/DeerLodge 301 South Park,Drawer 10096 MainStreet Helena,MT 59626 • MUannisvefriseiltdyoLfibMroarnyt/aMinsasoCulaampus 1-(406)449-5414 • MCoapnittaonlaCoStmaptleeLxibrary/Helena JSoalniide&StHilaezsaorrdNoeuilsMWaarssthe,MBuDrHeEaSu •• HU3eS0a1ErPsSAtouLFtirhberePaaLrirybk/rHaerlye/nAanaconda 8H3e6leFnrao.ntMSTtr5e9e6t01 FourthandMain 1-(800)648-8465 Mailing List IfyouwouldlikeinformationonanyMontanaSuperfundsite,pleasemailthisformtoPamHillery,USEPA,Montana Office,301 South Park,Drawer 10096,Helena,MT59626. Name Address City/State Zip Site(s) interested in- { EPARegion8 BULK RATE MontanaOffice | POSTAGE & FEES PAID 301 S. 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