ML070160199

JAFNPP - SEIS Web Reference - Lejeone Et Al 2000

ML070160199
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Site:	Quad Cities, FitzPatrick
Issue date:	12/31/2000
From:	Lajeone L, Monzingo R Commonwealth Edison Co, EA Engineering, Science, & Technology, Elsevier
To:	Office of Nuclear Reactor Regulation
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316(b)andQuadCitiesStation,CommonwealthEdisonCompanyLarryJ.LaJeone a,*,RichardG.Monzingo b aCommonwealthEdisonCompany,22710206thAvenueNorth,Cordova,IL61242,USA bEAEngineering,ScienceandTechnology,Deereld,IL60015,USA AbstractQuadCitiesStationisa1630MW edualreactorfacilitylocatedontheUpperMississippiRiverapproximately30milesnorthofDavenport,IowaandRockIsland,Illinois.Asdesigned,theStationutilizesriverwaterattherateof2270cfsinanopen-cyclemodeofoperation.Fromthe316(b)perspective,numerousagenciesandintervenorsexpressedmajorconcernregardingthepotentialadverseimpactsofopen-cycleentrainmentandimpingemente*ectsontheRiver'shighlyvaluedanddiverseshery.As aresult,thesheryhasbeenmonitoredcontinuouslysince1971througheldsurveysdirectedatmeasurementsofcommunitycompositionandrelativeabundance,aswellasshimpingementsurveysoftheStation'sintake.From1972to1983theStationoperatedinaclosed-cycleorpartialclosed-cyclemode.Regulatoryreliefandintervenorapprovalforopen-cycleoperationwerenotgranteduntil1984,followingseveralyearsofintensivestudiesdirectedatentrainment/impingementandmethodstoreduceimpingement.Beginningin1978,thefreshwaterdrumwasselectedastheindicatorspeciesmostlikelytomanifestchangesinpopulationcharacteristicspotentiallyresultingfrom open-cycleoperation.Populationlevels(numbersandbiomass),growth,fecundity,sexratiosandsurvivalwereallmonitoredtodetermineifcompensatoryresponsesoccurredwithinthepopulationfollowingincreasesinimpingementunderopen-cycleoperation.Includedintheagreementthatallowedthereturntoopen-cycleoperationwasacommitmenttoconstructand operateashproductionfacilitytomitigateforpotentialimpacts.After14yearsofmonitoringunderopen-cycleoperation,therehavebeennomeasurablechangesinthelocalsheryand,specically,nonewithinthefreshwaterdrumpopulation.Naturallyoccurringenvironmentalconditionshavemoreprofoundin-uencesonthisdynamicandresilientsherythanoperationofalargegenerationfacility.Stationoperationisrelatively constantfromyeartoyearandimpingementmonitoringmayactuallybethemostaccuratemonitoringactivity.Fluctuationsinannualimpingementprojectionsarere-ectionsofconditionswithintheriverandtheshery'sresponsetothem.IncreasesordecreasesinshnumbersimpingedattheStationinanygivenyearareprimarilydueto-uctuationsinthesheryandthe e*ectsofexistingenvironmentalvariablesandnottoStationoperation.Theshery-uctuationsarere-ectionsofconditionswithintheriverandtheshery'sresponsetothem.

72000ElsevierScienceLtd.Allrightsreserved.

Keywords:Powerplant;Fishentrainment;Fishimpingement;Ichthyoplankton;Survival;Populationestimates1.IntroductionAquaticbiologicalmonitoringofPool14oftheUpperMississippiRiver(UMR)inthevicinityofQuadCitiesStationhasbeenconductedcontinuously from1971tothepresent.ThroughoutthehistoryofQuadCitiesStation,thedesign,objectivesandin-terpretationofresultsfrommonitoringe*orts,aswellasspecialinvestigations,havebeenacollaborative e*ortinvolvingComEd,consultants,regulatoryagencies,resourcemanagersandintervenors.ASteer-ingCommittee,comprisedofrepresentativesfromallthesectorslistedabove,meetsannuallytoreviewstudyresultsfromthepreviousyearandtoformulate newdirectionforongoingwork.DuringthisperiodoftimetheStationhasoperatedinbothopen-andEnvironmentalScience&Policy3(2000)S313+/-S3221462-9011/00/$-seefrontmatter 72000ElsevierScienceLtd.Allrightsreserved.PII:S1462-9011(00)00030-7www.elsevier.com/locate/envsci*Correspondingauthor.Tel.:+1-309-654-2241,ext.2867;fax:+1-309-654-2178.E-mailaddress:larry.j.lajeone@ucm.com(L.J.LaJeone).

closed-cyclemodes.Thepurposefortheseinvesti-gationshasbeentodetermineiftherehavebeenany measurableadverseimpactstothelocalbiotaattribu-tabletoStationoperation,fromeitherthermaldis-charge[316(a)]orentrainment/impingement[316(b)].Earlyinvestigations(1971+/-1977)addressedallmajor trophiclevels;however,since1978studieshave focusedonmonitoringoftheRiver'shighlyvalued anddiverseshery.316(a)and(b)demonstrations wererstsubmittedtoUSEPAin1975(Common-wealthEdisonCompany,1975)followedbysup-plementaldemonstrationsin1981(CommonwealthEdisonCompany,1981).Aninitialaccountofshimpingementandimpactassessmentwaspreparedby Latvaitisetal.(1976).Morerecently,a24-yearsynop-sisofmajorsurveyndingsrelativetothelocalshery wasdevelopedbyBowzerandLippincott(1995).QuadCitiesStationhascommissionedmanymoreaquaticstudiesthananyotherfacilityintheComEd systemandwearenotawareofanyothergeneratingfacilitiesintheMidwestwithasextensiveadatabase.Wehaveconductedmoremonitoringthanistypical duetomajordesignchanges(closed-cycle,spraycanal) andbecauseofseriousquestionsraisedaboutpossiblee*ectsontheresource.Monitoringprogramsweredevelopedbyaconsensusofstakeholders.Theexten-sivemonitoringthathasbeenperformedhassuccess-fullyresolvedmanyissues.Ongoingmonitoringtodatecontinuestoconrmearlierresultsofnomeasur-ablee*ectsofStationoperationontheRiver'ssh community.Forallintentsandpurposes,ComEd's resolutionofissuesrelatedto316(b)atQuadCities Stationweresatisfactorilycompletedinlate1983with theissuanceofanewNPDESpermitallowingopen-cycleoperation.TheIllinoisEnvironmentalProtection Agency(IEPA)revisitsissuesrelatedto316(b)duringNPDESpermitrenewals.IEPAisaparticipantintheSteeringCommittee.2.ThestationanditsenvironmentalsettingTheUMRsegmentthatextendsfromStAnthonyFalls,MinnesotatoAlton,Illinoisisdividedintonum-berednavigationpoolseachseparatedbyalockand dam.QuadCitiesStationislocatednearthemid-pointofthissystemonPool14oftheUMR,approximately30milesnorthofDavenport,IowaandRockIsland,Illi-nois(Fig.1).TheStationisa1630MW edualreactorfacilitywhichbegancommercialoperationin1972.As designed,theStationutilizesriverwaterattherateof 2270cfsinanopen-cyclemodeofoperation.Conden-sercoolingwateriswarmedamaximumof12.8 8 C (23 8F)aboveambientbeforebeingdischargedtotheriver.TheoriginaldischargedesignforQuadCitiesStationwasanon-shoreside-jetdischargealongthe Illinoisbankoftheriver.Thisdesignwasutilizedfor only8monthswhenathermal-hydraulicstudydeter-minedthatthistypeofdischargewouldviolatethe StateofIllinoisthermalcriterium,whichlimitsthe maximumtemperatureriseto2.8 8C(5 8F)aboveambi-entattheedgeofthe600ftradiusmixingzone.TheStationdischargedesignwasthenmodiedintoamulti-portdi*userpipesystem,whichtransports heatedcondenserwaterouttothemainchannelofthe riverthroughtwo16ftdiameterpipes.Condenser waterisdischargedthroughaseriesof29-indiameter di*userportsacrossthetopofeachpipe.Withthis system,heatedcondenserwateriscompletelymixedwithriverwaterandmeetsthe2.8 8Ccriterionwithin500ftdownstreamofthedi*userpipes.TheStation operatedinanopen-cyclemodeonthisdi*usersystem fromAugust1972toMay1974.InresolutionofalawsuitbroughtbytheAttorneyGeneralofIllinois,theIzaakWaltonLeagueandthe UnitedAutoWorkers,ComEdconstructedano*-

streamspraycanalsystemforcoolingthecondenserdischargewaterfromtheStation.TheStationoperatedFig.1.Pool14oftheUpperMississippiRivernearQuadCities Station.L.J.LaJeone,R.G.Monzingo/EnvironmentalScience&Policy3(2000)S313+/-S322 S314 inaclosed-cycleorpartialclosed-cyclemodefromMay1974toDecember1983.However,thecoolingca-pacityofthespraycanalsystemwasinadequateto allownormalplantoperation,particularlyduringthesummermonths.Substantialgenerationderatingsoccurredthatresultedintheuseofgenerationfrom elsewhereintheComEdsystemtosupplementlost production.ConcurrentwiththehistoryoftheStation,extensivemonitoringoftheriver'ssheryhasbeenconducted eachyeartoassesstheimpactsofStationoperation.

Resultsofthesestudieshavenotdemonstratedanymeasurablee*ectsofStationoperationontheaquaticcommunitiesoftheriverundereitherclosed-cycleor open-cycleoperation.Theresultshavebeenandcon-tinuetobereviewedandapprovedbyindependent reviewers.Intheearly1980s,inconsiderationofthendingstodate,ComEdpetitionedtheregulatoryagenciesand intervenorstoallowQuadCitiesStationtoreturntoopen-cyclecoolingandtodiscontinuefurtheruseofthespraycanalforcoolingpurposes.Anewagreementwasreachedwiththeintervenorsallowingopen-cyclecoolingusingthedi*userpipesystem,contingentupon continuedmonitoringoftheshcommunity.This agreementbecamee*ectiveinlate-1983andtheStationcontinuestooperateinaccordancewiththeagreement.Aspreviouslymentioned,maximumcoolingwater-owfortheStationunderopen-cycleoperationis2270 cfs.Atlowriver-ow(16,000cfs),meanintakevelocity withallpumpsoperatingisapproximately1.5ft/sat thetravelingscreens.Intakevelocitymeasurements takenattheentrancetotheintakeforebayaveragedlessthan1.0ft/satariver-owof30,000cfs.Ataver-ageriver-ows(54,000cfs),intakevelocitiesarelower.

Whenambientriverwatertemperaturefallsbelow

4.4 8C(40 8F)inthelateautumn,coolingwaterrequire-mentsfortheStationcanbereducedbyonehalf.This isaccomplishedbyopeningtheice-meltrecirculation lineandbyidlingonecondensercirculatingwater pumpfromeachunit.Duringthisperiod,currentvel-ocitiesattheforebayentranceandtravelingscreensarealsoreducedbyapproximately50%.Fig.2.Cumulativepassagesoftotallarvaeandfreshwaterdrumlarvae,andmeanwatertemperatureinPool14,QuadCitiesStation,1984+/-1985(dataaremeanof2years).L.J.LaJeone,R.G.Monzingo/EnvironmentalScience&Policy3(2000)S313+/-S322 S315 3.Monitoringe*ortsMonitoringthepotentialimpactsofStationoper-ationontheshcommunityofPool14hasoccurredcontinuouslyfrom1971todateusingavarietyoftra-ditionalcollectiontechniquesandsamplingstrategies.

Detaileddescriptionsofsamplingmethodologies,lo-cationsandequipmentarenotincludedinthispaper, butcanbefoundinannualreportssubmittedto ComEd.Theobjectivesofthesee*ortsweredirected atmeasurementsofcommunitycompositionandrela-tiveabundance.MoredirectapproximationsofpotentialStationimpactsweredevelopedthroughichthyoplanktondrift/

entrainmentsurveysandimpingementmonitoring.

FishimpingementatQuadCitiesStationhasbeen monitoredfrom1973todateandannualprojections oftotalimpingementarereportedtoIEPA.Ichthyo-planktondriftandentrainmenthavebeenmonitored atvaryinglevelsofintensityfrom1975to1985.Shortlyafterthespraycanalbecameoperationalinmid-1975andtheStationchangedfromopen-cycleop-erationtoclosed-cycleoperation,itbecameapparent thatitscoolingperformancewasunacceptable.Power productionwasfarbelowcapacityandtheStation couldnotoperateeitherecientlyoreconomically.

BeforeanymodicationstoexistingNPDESpermits orintervenoragreementscouldbeconsidered;how-ever,specicquestionsandconcernsregardingoper-ationalimpactsontheshcommunityhadtobe addressed.Consequently,in1978somemonitoring programelementswereintensiedandadditional specialstudiesweredeveloped.Ichthyoplanktondrift/entrainmentsamplingwasgreatlyexpandedin1978andsupplementedwithan intensivestudyonentrainmentsurvival(Restainoetal.,1979).Thise*ortwasessentiallyduplicatedagainin1984,theStation'srstyearofreturningtoopen-cycleoperation(Lawler,Matusky&SkellyEngineers(LMS),1985).In1979,experimentationbeganwithanetbarriersystemacrosstheentranceoftheintake forebayinane*orttoreduceshimpingementlosses (CommonwealthEdisonCompany,1981).Backwaterrotenonesurveysandsamplingwithhaulseineswerealsoaddedin1978toestimatethestandingcropof certainshspecieswithinPool14.Resultsofthese e*ortswerethencomparedwithimpingementesti-matestoprovidesomeapproximationofcropping e*ectsonpopulationlevels.Whilenolistof`representativeimportantspecies'hadbeenformulatedtoaddress316(b)issues,dialogbetweenComEd,regulatoryagenciesandintervenorsidentiedtheneedtostudythepotentialimpactsof open-cycleStationoperationonthepopulation dynamicsandvariouslifehistoryparametersofash speciesmostlikelytobea*ected.Thefreshwaterdrum wasselectedforthesespecialstudiesbasedonitsover-allabundancethroughoutPool14,thevulnerabilityof planktonicearlylifestagestoentrainment,andthehighnumbersroutinelyencounteredinimpingementcollections.Aseriesofspecialstudiesbeganin1978 whosefocuswastomonitorpopulationlevels(num-bersandbiomass),growth,fecundity,sexratiosand survivaloffreshwaterdrumtodetermineifcompensa-toryresponsesoccurredwithinthepopulationfollow-ingincreasesinimpingementunderopen-cycle operation.Therelativelyhighnumbersoffreshwaterdrumimpingedduringthewinteralsowasofparticu-larconcern,soaspecialresearchprojectwascommis-sionedtotryanddeterminethecause(Lewisand Bodensteiner,1985).Manyofthesespecialprogramel-ementsremainactivemonitoringe*ortstodayaspart oftheStation'scommitmentforcontinuedmonitoring.4.ResultsanddiscussionAssessingthepotentialimpactsofichthyoplanktonFig.3.MeanannualimpingementcompositionatQuadCitiesStationduringopen-cycleoperation,1984+/-1994.L.J.LaJeone,R.G.Monzingo/EnvironmentalScience&Policy3(2000)S313+/-S322 S316 entrainmentrstrequiredacharacterizationofthecomposition,distributionanddurationofthe`drift'.

InPool14,theichthyoplanktondriftseasontypically runsfrommid-Aprilthroughlate-July,althoughafew`straggler'larvaecanstillbefoundinAugust.Thereisminimaltonodi*erenceindensitybetweendayvs nightcollectionsnorindepthwithinthewatercolumn.

Ichthyoplanktondensitytypicallyishigheralongthe Illinoisbank(Stationside)thanalongtheIowabank orinmidchannel,butnotforalltaxa.Freshwater drumdominatethedriftassemblage,comprisingover 80%oftheeggscollectedand57%ofalllarvae.Othercommonspeciesareemeraldshinerandcommoncarp.Lessercontributionscomefromsunshes,gizzardshad andbu*aloes.Thoughthedriftseasonextendsfrommid-ApriltoJuly,thepeakperiodoflarvaldriftoccursfromlate-Maytoearly-July,whichcoincideswiththepeakin freshwaterdrumabundance(Fig.2).Duringthis period,watertemperaturesrangefrom18to24 8C(64+/-75 8F).Byearly-July,almost85%ofalllarvaeandupto97%offreshwaterdrumlarvaehavepassedthe Station.Theseobservationsareintegralinevaluating themagnitudeofentrainmentimpacts.Underopen-cycleoperation,assumingtheworstcasescenariooftotalmortalityofallentrainedichthyoplankton,itisasimplemattertoestimatethe numbersofichthyoplanktonentrainedcomparedto thetotal-uxofichthyoplanktonpassingtheStation andcalculateapercentageofloss.Underthesecon-ditions,projectedentrainmentlossescouldhavebeen reportedashighas5.4%oftotalichthyoplankton (CommonwealthEdisonCompany,1981).However,anumberofstudiesatotherstationshaveshownthattheassumptionof100%mortalityisnotvalid(Eco-logicalAnalysts,Inc.,1977;Cada,1977;King,1978; StevensandFinlayson,1978).Entrainmentsurvival studiesconductedatQuadCitiesStationin1978 (Restainoetal.,1979)andagainin1984and1985 (Lawler,Matusky&SkellyEngineers,1985,1986) demonstratedthatsubstantialpercentagesofentrained ichthyoplanktondosurvivecondenseranddi*user passagedependingonStationoperatingcapacityand intakewatertemperature.Atdischargetemperatures ofupto33 8C(91.4 8F),Restainoestimatedlarvalsur-vivalofupto70%.LMSreportedsimilarresultsin 1984.Aslongasdischargetemperaturesdonotexceed

37.8 8C(100 8F),someentrainmentsurvivaldoesoccur.ApplyingthesesurvivaldatainreferencetoFig.2,84%ofalllarvaeand97%offreshwaterdrumlarvae willhavepassedQuadCitiesStationbeforedischarge watertemperaturesbecometoowarmtoexpectsome levelofentrainmentsurvival.In1984,LMS(1985) estimatedthatStationimpactontotallarvae,assum-ing100%mortality,rangedfrom0.1to0.7%,depend-ingontaxon.However,afterapplyingentrainmentsurvivaldatatofreshwaterdrum,commoncarpand bu*alospecies,therangeofimpactonthesespecies were0.0006+/-0.10%,0.0000+/-0.0055%,and0.000+/-

0.004%,respectively.Theseprojectionsofcropping arenotconsideredtoadverselya*ecttheshcommu-nityofPool14.Theissueofshlossesduetoimpingementwasofgreaterconcerntothestakeholders,particularly regardingthereturntoopen-cycleoperationin 1984.Resourcemanagementagenciesandinterve-norsrecognizedthatimpingementnumberswould probablyincreaseunderopen-cycleoperationand, asamitigativeaction,securedacommitmentfrom ComEdtoconverttheinactivecoolingcanalintoa gameshrearingfacility.Fishproducedinthe canalareearmarkedforstockingPool14asa meansofincreasinggameshpopulationsand improvingsportshingopportunitiesinthearea.FishimpingementhasbeenhighlyvariableoverthehistoryoftheStationduetothreedi*erent modesofoperation,experimentationwithanetbar-riersystem,natural-uctuationsinshabundanceandmajorperturbationsa*ectingtheenvironment.Assessingtheimpactofimpingementon91sh speciesknowntooccurinPool14oftheUMRisFig.4.MeanmonthlyimpingementestimatesofdominantshspeciesatQuadCitiesStationunderopen-cycleoperation,1984+/-

1994.L.J.LaJeone,R.G.Monzingo/EnvironmentalScience&Policy3(2000)S313+/-S322 S317 simpliedbythefactthatonlyafewspeciesareimpingedinhighenoughnumberstowarranta detaileddiscussion.Gizzardshadandfreshwater drumdominateannualimpingementprojections(Fig.3).Collectively,thesetwospeciesaccountforalmost90%ofthenumbersandbiomassofallsh impinged.Farlowercontributionsaremadeby bluegill(5%bynumber,1.6%byweight),white bass(1.9%bynumber,1.2%byweight)andchan-nelcatsh(1.7%bynumber,1.1%byweight).The remaining86speciestypicallyaccountfor4%by numberand5.5%byweight.Inmostyears,impingementincreasesduringtheautumnandremainshighthroughoutthewinterand springregardlessofStationoperationalmode(Fig.4).

Thegreatestnumberofshtypicallyareimpinged duringthewintermonths,withfewershbeing impingedduringtheMaytoAugustperiod.Gizzard shadimpingementusuallypeaksinJanuaryandFeb-ruarycoincidentwiththestressesoffreezingornear-freezingwatertemperatures.Asgizzardshadnumbersdecline,freshwaterdrumnumbersincreaseandpeakin MarchorApril.Impingementofbluegill,whitebass andchannelcatshpeakinApril,July,andAugust+/-

September,respectively.Impingementisprimarilycomprisedofyoungsh(young-of-yearoryearlings)which,particularlyinthecaseofgizzardshadand freshwaterdrum,cannottoleratethenear-freezing watertemperaturesthatoccurinthemainchannelandsidechannelsduringthewintermonths(BodensteinerandLewis,1992,1994).Figs.5and6illustrateannualimpingementprojec-tionsfrom1973to1996.Projectionsmadefrom1974 to1978(closed-cycleorpartialclosed-cycle)aresimilar toprojectionsfrom1984to1987(open-cyclewithnet barriersystem).Lowimpingementprojectionsfrom 1979to1983representaperiodofpartialclosed-cycleoperationwiththenetbarriersystem.Whilethenetbarriersysteme*ectivelyreducedimpingementunder partialclosed-cycleStationoperation,itcouldnot functione*ectivelyundertheincreasedintake-owsof open-cycleoperation.Debrisandshaccumulatedon thenetssoquicklythatane*ectivebarriertothe intakeforebaycouldnotbemaintained.Attemptsto utilizethenetbarriersystemunderopen-cyclecon-ditionscontinueduntil1990whentheStation'sNPDESpermitwasamendedtoremovethatspecial conditionasarequirement.Projectionsfor1988and 1989werethehighestimpingementestimatesinthe Station'shistory,bothyearsinwhichthenetbarrierFig.5.EstimatednumberofshimpingedatQuadCitiesStationfrom1973to1996.L.J.LaJeone,R.G.Monzingo/EnvironmentalScience&Policy3(2000)S313+/-S322 S318 systemwasstillinuse.Observationsontheconditionofshentrappedonthebarriernetaidedinthede-cisiontoabandonthisrequirement.Duringthe4 monthsthatthenetwasdeployedin1984(January,February,November,December),over90%ofallshentrappedonthenetwereeitherdeadormoribund,as conrmedbymonitoringe*ortsthatcollectedand analyzedshfromthenet,afterithadbeencleaned, overtwo2-hcollectionperiodsweekly(Lawler, Matusky&SkellyEngineers,1985).Fishimpingement atQuadCitiesStation,thoughrelativelyhigh,does notrepresentadirectimpactontheshcommunitybecausethevastmajorityofshimpingedbytheStationaredeadormoribundupontheirarrivalinthe intakeforebay.Theseindividualsareessentiallylost fromtheshery,whetherornottheybecome impinged.Inreviewingthelong-termdatabasedevelopedfromthein-streammonitoringprogramandpopu-lationstudies,therehavebeenwide-uctuationsinabundanceamongprincipalspecies,butcommunitycompositionhasremainedrelativelystable(Lawler, Matusky&SkellyEngineers,1995).Theshcommu-nityremainsdominatedbygizzardshadandfresh-waterdrum,withemeraldshiner,rivershiner,bullheadminnow,commoncarpandbluegillalsoabundant.Paddleshandwhitecrappiehavedeclinedinabun-dance,butmodestnumbersoflakesturgeonhavebeen collectedinrecentyears.Channelcatshhavegreatlyincreasedinabundancedueprimarilytomajorchangesincommercialharvestregulationsthathavebeneted reproductivepotential.Bertrand(1997)reportedsimi-larchangesintheshcommunitythroughouttheIlli-noisportionoftheUMRandattributedthesechanges tothedeclineinqualitybackwaterhabitatasaresult ofsiltation.Walleyeabundancehasincreasedmeasur-ablyinrecentyearsasaresultofstockingngerlingshrearedintheinactivecoolingcanalatQuadCitiesStation.Conservatively,theadultwalleyepopulation inPool14ispresentlycomprisedof30%stockedsh, withlesser,yetmeasurable,contributionstodown-streampools.Lifehistorystudiesoffreshwaterdrumhaveshownwide-uctuationsinpopulationlevels,standingcrop andcatchrates,butsurprisinglylittlevariationinmostotherparametersmeasured.Therehavebeennonotablechangesinlineargrowth,fecundity,sexratios orsurvivalestimatesthatcanbeattributedtoStation operation.However,thereisoneperiodofrecord worthyofdiscussion,aprolongeddroughtthatFig.6.EstimatedweightofshimpingedatQuadCitiesStationfrom1973to1996.L.J.LaJeone,R.G.Monzingo/EnvironmentalScience&Policy3(2000)S313+/-S322 S319 extendedfrom1987to1989.In1987,adultpopulationlevelswerethelowestevercalculated(Fig.7).Low, stablewaterlevelsthatfollowedoverthenext2years resultedinhighrecruitmentandgoodsurvival,which inturnresultedinthehighestpopulationestimateever calculated.Between1989and1990thedrumpopu-lationexhibitedclearsignsofstressthroughcompe-titionforavailableresources.Averageweightofadult shdeclineddramatically(Fig.8),andmeanfecundity (no.ova/100gbodyweight)declinedbyalmost20%.

Survival,whichaverages71%bythecatchcurve method,alsodeclinedto47%and52%in1989and1990,respectively.Thin,emaciatedshwerecommonandimpingementestimatesroseaccordingly.The returntoamorenormalwateryearin1991,preceded by2yearsofrelativelyhighmortality,resultedinsub-stantialincreasesinaverageweight,increasedfecund-ity,averagesurvivalandamarkeddeclinein impingement.Itwouldappearthatnaturalmechan-ismsofcompensationwerefunctioning.Severalprogramelementshavebeensucientlysen-sitivetodocumentchangesforseveralspeciesfollow-ingmajorhydrologicevents.Electroshingcatchesand impingementmonitoringdetectedincreasedrecruit-mentandabundanceoflargemouthbass,bluegillandgizzardshadduringthesameprolongeddroughtof 1987+/-1989.Thesesameprogramelementsdetected verypoorrecruitmentamongseveralshspecies duringtheprolongedrecord-oodof1993.Arecord fall-oodduringOctober1986greatlyin-uenced impingementcollections.Duringthatevent,largenum-bersofyoung-of-yearcommoncarpandlargemouth basswereimpinged.Neitherspecieshasevercom-prisedmorethanasmallfractionofimpingementcol-lectionsthroughouttheentire25-yearmonitoring program,exceptduringthisperiod.Therewasnoevi-denceinsubsequentyearsthatthiseventhadanadverseimpactonthepopulationsofeitherspecies.

Theseyoungshwerewashedoutofprotectedhabi-tatswheretheywouldhaveoverwintered.Impingementmonitoringhasbeenoneofthemostinformativeandsensitiveofalldatagatheringtech-niquesusedatQuadCities.Nuclearstationsoperate as`baseload'facilities.Consequently,thereisonly minorvariationincoolingwaterusagebetweenyears andtheirin-uenceremainsrelativelystable.Wide annual-uctuationsinthenumbersofshimpinged re-ectactualchangesinshabundanceinthepool,Fig.7.Freshwaterdrumpopulationestimatesfromlong-termsamplingareasinPool14,1983+/-1997.L.J.LaJeone,R.G.Monzingo/EnvironmentalScience&Policy3(2000)S313+/-S322 S320 andmeasureclimaticandhydrologice*ectsonshsurvival.5.SummaryTwenty-sevenyearsofsheriesmonitoringinPool14oftheUMRhavebeenconductedinane*ort todeterminewhetheroperationofQuadCitiesStationhashadameasurableimpactonshpopu-lationsinthepool.Overthepast14years,e*orts havebeendirectedatevaluatingpossiblee*ectsof open-cycleoperation,whichincludedischargee*ects aswellasentrainment/impingement.Areviewof thislong-termdatabasehasledtotheconclusion thattheUMRisanextremelydynamicecosystem, whichisin-uencedbymanynaturalvariablesthata*ecttheentireecosystem.Thesevariablesmayop-erateindependentlyorinconsortwithoneanother, andsimilarenvironmentalconditionsseldom,if ever,occurduringconsecutiveyears.Thefactthat individualorganismsarelostduetoentrainment andimpingementbytheStationisnotdisputed.In estimatingthenumberofshlosttotheriverby impingement,thedirectimpactisconfoundedbytheobservationthatthemajorityoftheseshareeitherdeadormoribundpriortotheirarrivalontheStation'sintakescreens.Theselong-termstudieshavenotidentiedanymeasurableadverseimpactofopen-cycleoperationontheshcommunityofPool14.Onemajoradvantageofthislong-termdatabasehasbeentheopportunitytoobserveseveralperiodsofcyclic-uctuationswithintheshcommunity,andthehighdegreeofvariabilitywithinthefreshwaterdrumpopulation.Thein-uencesofnaturallyoccurringen-vironmentalperturbations(-oods,drought,andseverewinter)mayhavemoreprofounde*ectsontheshcommunitythanoperationofalargegenerationfacility.BecauseStationoperationisrelativelyconstantfromyeartoyear,impingementmonitoringmaybethemostsensitiveassessmenttoolofall.Fluctuationsinannualimpingementestimatesarere-ectionsofen-vironmentalconditionswithintheriverandthesh-ery'sresponsetothem.IncreasesordecreasesinshnumbersimpingedattheStationinanygivenyearareprimarilydueto-uctuationsinthesheryandthee*ectsofprevailingenvironmentalvariablesandnottoStationoperation.ConversionoftheinactivecoolingcanalintoagameshrearingfacilityandthesubsequentsupplementalFig.8.Freshwaterdrumaverageweightat350mmtotallength,1980+/-1997.L.J.LaJeone,R.G.Monzingo/EnvironmentalScience&Policy3(2000)S313+/-S322 S321 stockingofgameshintoPool14followingthereturntoopencycleoperationhasresultedina`win+/-win' situationforallpartiesinvolved.Regulatoryagencies, intervenorsandComEdviewthismitigationasafairandequitablesolutiontoanarguableissue.Rec-reationalanglingopportunitieshavegreatlyimproved inPool14andseveralothernavigationpoolsasa resultofthiscommitment.Insummary,theshpopulationofPool14oftheUMRisextremelydynamicandresilient.Individual speciesandtheoverallsheryhaveexhibitedboth long-termandshort-term-uctuationsinresponsetoawiderangeofenvironmentalin-uences.Thislong-termdatabasea*ordstheopportunitytoobservemultiple occurrencesofshort-termcycles,overcomingapro-blemwithshort-terminvestigations,i.e.,theinvesti-gatorcannotfullyinterpretatwhichpointthecycle wasenteredwithoutadditionalinformation.Wedonotadvocateorbelievethateveryfacilityneedstocompilesuchalengthyrecordofdocumen-tation.However,whenandwhererecenthistoricalsh-erydataareavailable,theyshouldbereviewedtoaid inevaluatingthecurrentstatusoftheshcommunity.

Regulatorsandresourcemanagers,whomustbasede-cisionsandactionsonshort-terminvestigationsof aquaticecosystems,areurgedtobalancethedesirefor extensivesitespecicdatawiththeutilityofthatdata.ReferencesBertrand,W.A.,1997.ChangesintheMississippiRiverFisheryalongIllinois,1976+/-1996.JournalofFreshwaterEcology12(4), 585+/-597.Bodensteiner,L.R.,Lewis,W.M.,1992.Roleoftemperature,dis-solvedoxygen,andbackwatersinthewintersurvivaloffresh-waterdrum(Aplodinotusgrunniens)intheMississippiRiver.CanadianJournalofFisheriesandAquaticSciences49,173+/-184.Bodensteiner,L.R.,Lewis,W.M.,1994.DownstreamdriftofshesintheupperMississippiRiverduringwinter.Journalof FreshwaterEcology9(1),45+/-56.Bowzer,T.W.,Lippincott,B.L.,1995.ASynopticReviewofLong-termFisheriesMonitoringinPool14oftheUpperMississippi RivernearQuadCitiesStation.PreparedforCommonwealth EdisonCompany,Chicago,IL.65pp.Cada,G.F.,1977.TheEntrainmentofLarvalFishesatTwoNuclearPowerPlantsontheMissouriRiverinNebraska.Ph.D.thesis.

UniversityofNebraska,Lincoln,Nebraska.133pp.CommonwealthEdisonCompany,1975.Three-sixteena&bDemonstration.QuadCitiesNuclearStation,MississippiRiver.AdemonstrationtoTheUnitedStatedEnvironmentalProtectionAgency,Washington,DC.296pp.CommonwealthEdisonCompany,1981.Supplementto316(a)and316(b)DemonstrationforQuadCitiesNuclearGenerating Station.Chicago,Illinois.181pp.EcologicalAnalystsInc.,1977.SurvivalofEntrainedIchthyoplanktonandMacroinvertebratesatHudsonRiverPower Plants.ReportpreparedforCentralHudsonGas&ElectricCo.,

ConsolidatedEdisonCo.ofNewYork,Inc.andOrangeandRocklandUtilities,Inc.114pp.King,R.G.,1978.EntrainmentofMissouriRivershlarvaethroughFortCalhounStation.In:ProceedingsofFourthNationalWorkshoponEntrainmentandImpingement,Chicago,Illinois,5December1977,pp.45+/-56.Latvaitis,P.B.,Bernhard,H.F.,McDonald,D.B.,1976.ImpingementstudiesatQuadCitiesStation,MississippiRiver.In:ProceedingsofThirdNationalWorkshoponEntrainmentandImingement:Section316(b)researchandcompliance.New York,24February1976,pp.269+/-289.LawlerMatuskySkellyEngineers(LMS),1985.QuadCitiesAquaticProgram,1984.PreparedforCommonwealthEdisonCompany,Chicago,Illinois.LawlerMatuskySkellyEngineers(LMS),1986.QuadCitiesAquaticProgram,1985.PreparedforCommonwealthEdisonCompany,Chicago,Illinois.LawlerMatuskySkellyEngineers(LMS),1995.QuadCitiesAquaticProgram,1994.PreparedforCommonwealthEdisonCompany,Chicago,Illinois.Lewis,W.M.,Bodensteiner,L.R.,1985.StateofHealthofFreshwaterDrum(Aplodinotusgrunniens)throughtheWinterinPool14oftheMississippiRiver.InterimreporttoCommonwealthEdisonCompany,Chicago,IL.;BytheCooperativeFisheriesLaboratory,SouthernIllinoisUniversity, Carbondale,Illinois.Restaino,A.L.,Bartholomew,P.S.,McGrath,M.J.,1979.TheSurvivalofEntrainedIchthyoplanktonatQuadCitiesStation,1978.ReporttoCommonwealthEdisonCompany,Chicago, Illinois.59pp.Stevens,D.E.,Finlayson,B.J.,1978.MortalityofyoungstripedbassentrainedattwopowerplantsintheSacramento-SanJoaquin Delta,California.In:ProceedingsofFourthNationalWorkshop onEntrainmentandImpingement.Chicago,Illinois,5December1977,pp.57+/-70.LarryJ.LaJeonehasbeenProjectManagerforallenvironmentalstudiesatQuadCitiesStationfrom1983tothepresent.HeobtainedaB.A.inBiologyfromBuenaVistaCollege,StormLake,Iowain1969andaM.Sc.inZoology(Fisheries)fromSouthernIllinoisUni-versity,Edwardsville,Illinoisin1972.RichardG.MonzingowasemployedbytheCommonwealthEdisonCompanyfor24years.HislastpositionwasasPrincipleTechnicalExpertforBiology.HeobtainedaB.A.inBiologyfromHunterCol-lege,NewYorkin1968,aM.Sc.inZoologyfromLehighUniversity,Bethlehem,Pennsylvaniain1970andaPh.D.inZoologyfromLehighUniversity,Bethlehem,Pennsylvaniain1973.L.J.LaJeone,R.G.Monzingo/EnvironmentalScience&Policy3(2000)S313+/-S322 S322