final white paper drinking water issues 20170620€¦ · final white paper prepared for: delta...

Delta Nutrients

Drinking Water Issues

FINAL White Paper

Prepared for:

Delta Nutrient Science and Research Program

Stakeholder and Technical Advisory Group

June 20, 2017

DeltaNutrients–DrinkingWaterIssues i June20,2017

Acknowledgements

ThewhitepaperistheresultofastakeholdergroupeffortbytheDeltaNutrientDrinkingWaterWorkgroup.Participantsinthisgroupinclude:

ElaineArchibald,ArchibaldConsulting

LyndaSmith,MetropolitanWaterDistrictofSouthernCalifornia

TerrieMitchell,SacramentoRegionalCountySanitationDistrict

LysaVoight,SacramentoRegionalCountySanitationDistrict

DebbieWebster,CentralValleyCleanWaterAssociation

KyleEricson,CityofSacramento

TonyPirondini,CityofVacaville

JenniferClary,CleanWaterAction

AndriaVentura,CleanWaterAction

MikeWackman,DeltaAgriculturalCoalition

ChrisFoe,CentralValleyRegionalWaterQualityControlBoard

ChristineJoab,CentralValleyRegionalWaterQualityControlBoard

JanisCooke,CentralValleyRegionalWaterQualityControlBoard

TomGrovhoug,LarryWalkerAssociates

BrianLaurenson,LarryWalkerAssociates

MikeTrouchon,LarryWalkerAssociates

RachelPisor,CaliforniaDepartmentofWaterResources

DeltaNutrients–DrinkingWaterIssues ii June20,2017

DeltaNutrients–DrinkingWaterIssues iii June20,2017

Executive Summary

TheSacramento–SanJoaquinRiverDelta(Delta)isakeycomponentofCalifornia’swaterresourcesystemandservesasanimportantsourceofdrinkingwatertoover25millionCalifornians.However,issuesassociatedwithinvasivemacrophyteandcyanobacteriagrowthhavebeenincreasingoverthelastdecadeaddingsignificantconcernassociatedwithinfrastructureclogging,tasteandodorissues,andrisingcyanotoxinconcentrations.Bothmacrophyteandcyanobacteriagrowthareaffectedbyconcentrationsofthenutrientsnitrogenandphosphoruswhicharerequiredfortheirgrowth.However,theconnectionbetweennutrientsandinvasivemacrophytesandharmfulcyanobacteriaiscomplexandremainsanactiveareaofstudy.Thisdocumentprovidesasynthesisofthecurrentstateofknowledgeregardingnutrient‐relateddrinkingwaterissuesintheDeltaanddownstreamconveyanceandstoragefacilities,andpresentsasetofrecommendationstoaddressdatagapsinmonitoring,research,andmodelinginordertosupportpolicydecisionsonnutrientmanagement.

TheCentralValleyRegionalWaterQualityControlBoard(CentralValleyWaterBoard)andstakeholdershaveinvestedsignificantresourcesintounderstandingthesciencebehindtheseissuesinordertomakesound,science‐basednutrientmanagementpolicydecisionsinthefuture.TheyhaverecentlycompletedthefollowingWhitePaperswhichservedasafoundationfortheresearchsummarizedinthisdocument:

CyanobacteriaWhitePaperandKnowledgeGapDocument MacrophyteWhitePaperandKnowledgeGapDocument ModelingWhitePaper

AllofthesedocumentscanbefoundontheCentralValleyWaterBoardwebsiteundertheScienceWorkGroupssection:www.waterboards.ca.gov/centralvalley/water_issues/delta_water_quality/delta_nutrient_research_plan/science_work_groups/index.shtml.

ARoleofNutrientsinShiftsinPhytoplanktonAbundanceandSpeciesCompositionintheSacramento‐SanJoaquinDeltaWhitePaper(a.k.a.FormsandRatiosWhitePaper)wasrecentlyreleasedthatdiscussestheroleofnutrientformsandratiosintheDelta.However,duetoitsrecentsubmittal,itscontentswerenotsummarizedinthisdocument.WeencourageinterestedreaderswhowanttoknowmoreabouttheseparticularissuestoreadtheotherassociatedWhitePapers.

ThisdocumentprovidesasynthesisofthecurrentstateoftheknowledgeregardingnutrientsintheDelta,highlightstheuniquenutrient‐relateddrinkingwaterqualityissuesfacedbytheDeltaandwatersupplyproviders,exploresfactorswhichinfluencemacrophyteandcyanobacteriagrowth,presentsmanagementoptionstodealwiththeseissues,andidentifiesdatagapswhichrequireadditionalresearchandmonitoring.Themainnutrient‐relateddrinkingwaterissuesidentifiedinclude:

Tasteandodorissuesduetocyanobacteriagrowth, Cyanotoxinreleasebyharmfulcyanobacteriablooms,and

DeltaNutrients–DrinkingWaterIssues iv June20,2017

Filterand/orpumpcloggingbymacrophytesandalgae. Section6.0ofthisdocumentsynthesizestheinformationpresentedinprevioussectionsandoutlinesasetofrecommendationsforadditionalmonitoring,research,andmodelingpriorities.Highlightsoftheserecommendationsincludethefollowing:1. Cyanobacteria–Cyanotoxins:Expandsystem‐widemonitoringintheDeltaanddownstreamfacilitiesinordertoidentifythelocation,timing,anddurationofcyanotoxin‐producingcyanobacteriabloomsandthethreatthatcyanotoxinspose.Determineviafieldandlaboratorystudiesifancillarybiological(e.g.,chlorophylla),chemical(e.g.,nutrients),orphysical(e.g.,temperature,irradiance,flow)measurementsco‐varywithbloomssuchthattheycouldbeusedtopredict,limitinitiation,and/ormanagedurationofcyanobacterialblooms.

2. Cyanobacteria–TasteandOdors:Expandsystem‐widemonitoringindownstreamfacilitiesinordertoidentifythelocation,timing,anddurationoftasteandodorcyanobacteriaevents.MeasureasuiteofenvironmentalparametersincludinggeosminandMIB(thecompoundsresponsiblefortasteandodorevents),nutrients,andperformmicrobialsurveysinordertoexpandknowledgeofpossibledriversoftasteandodorevents.Determineviafield(includinginsituormesocosmstudies)andlaboratorystudiesifancillarybiological(e.g.,specificbenthicorplanktonicspecies),chemical(e.g.,nutrients),orphysical(e.g.,temperature,irradiance,flow)measurementsco‐varyorcontributetotasteandodorinitiationandattenuation.

3. Macrophytes:Expandsystem‐widemonitoringintheDeltaanddownstreamfacilitiesinordertodeterminetheabundanceandextentofinvasivemacrophyteblooms(includingnewinvasivespecies)aswellasanyco‐occurringenvironmentalparametersthatmightcontributetotheirgrowth,andtodeterminewheremacrophytebloomsareimpactingoperationsofwatersupplyfacilities.Performfieldandlaboratorystudiestodeterminemacrophytegrowthrateasafunctionofnutrientconcentrations,includingnutrientuptakerates,andpossiblemethodsforinsituassessmentofnutrientlimitation.Conductinsitustudiestotesttheeffectnutrientlimitationmayhaveontheenhancementofmechanicalandchemicalmacrophytecontrol.

4. ModelingScenarios:Utilizemodelstocharacterizeandtestmanagementactionsoverarangeofconditions,provideinsightintothesignificanceofnutrientsontheecosystem,andcommunicateinformationtostakeholders,regulators,andresourcemanagerstoarriveatconsensusandunderstandingofthesystem.

5. ManagementConsiderations:Oncemonitoringandmodelingeffortshavematured,theseeffortsshouldbeusedtoaddressthequestionofwhethernutrientreductionsaloneorinsomecombinationwithothermanagementpracticeswillbeeffectivetosignificantlyreducetasteandodor,cyanotoxinissues,andfilter/pumpcloggingproblemsintheDeltaanddownstreamfacilities.

DeltaNutrients–DrinkingWaterIssues v June20,2017

Table of Contents

Acknowledgements........................................................................................................................................i

ExecutiveSummary.....................................................................................................................................iii

ListofTables................................................................................................................................................viii

ListofFigures...............................................................................................................................................viii

1.0Introduction,Purpose,andOrganizationoftheReview...........................................................1

1.1BackgroundandContext.....................................................................................................................................1

1.2GoalandOrganizationofDrinkingWaterIssuesLiteratureReview................................................2

2.0Nutrient‐RelatedDrinkingWaterIssues........................................................................................5

2.1DeltaNutrientsBackground...............................................................................................................................5

2.1.1DeltaHydrology................................................................................................................................................5

2.1.2TheStateWaterProject................................................................................................................................5

2.1.3ContraCostaWaterDistrict.........................................................................................................................7

2.1.4NutrientConcentrationsintheDeltaandSWP...................................................................................8

2.2ProblemsAssociatedwithHighNutrientLevelsandotherEnvironmentalFactors................13

2.3AlgaeandMacrophyteProblemsinDrinkingwaterSupplies...........................................................13

2.3.1NuisanceAlgaeandHarmfulCyanobacteriaBlooms......................................................................13

2.3.2Macrophytes....................................................................................................................................................30

3.0FactorsInfluencingNutrient‐RelatedDrinkingWaterIssues.............................................32

3.1Light/SolarIrradiance........................................................................................................................................32

3.2Waterclarity...........................................................................................................................................................33

3.3Temperature...........................................................................................................................................................33

3.4Residencetime/flow...........................................................................................................................................34

3.5Salinity.......................................................................................................................................................................35

3.6Nutrientconcentrationsandratios...............................................................................................................35

3.7Dissolvedinorganiccarbon..............................................................................................................................36

DeltaNutrients–DrinkingWaterIssues vi June20,2017

4.0ManagementofIdentifiedIssues....................................................................................................37

4.1Managementoptions...........................................................................................................................................37

4.1.1NutrientLoadManagement.......................................................................................................................37

Cyanobacteria.............................................................................................................................................................38

Macrophytes...............................................................................................................................................................38

4.1.2Harvesting(macrophytes).........................................................................................................................38

4.1.3BiologicalControl(macrophytes)...........................................................................................................39

4.1.4ChemicalAdditions(e.g.coppersulfate,etc.fornuisancealgalblooms,tasteandodorepisodes)..............................................................................................................................................................39

5.0DataGaps.................................................................................................................................................40

5.1PrevalenceofProblemsintheDeltaandDownstreamConveyanceandStorageFacilities..40

5.2Spatialandseasonaloccurrenceofproblems...........................................................................................41

5.3Effectivenessofalternativemanagementoptionsonspecificproblems......................................41

5.4Monitoringdataandprocesscoefficients/parametersrequiredforecosystemandmanagementmodels...........................................................................................................................................42

6.0RecommendationsforMonitoring,ResearchandModelingPriorities............................43

6.1Problemdefinition...............................................................................................................................................43

6.2Roleofnutrientsincombinationwithotherfactors..............................................................................43

Cyanobacteria–Cyanotoxins...............................................................................................................................43

Cyanobacteria–TasteandOdors.......................................................................................................................44

Macrophytes...............................................................................................................................................................45

6.3Modelingtoolsandscenarios..........................................................................................................................46

DevelopmentofModelingTools.........................................................................................................................46

ModelingScenarios..................................................................................................................................................47

6.4Effectivenessofmanagement..........................................................................................................................48

7.0LiteratureCited.....................................................................................................................................49

AppendixA.....................................................................................................................................................58

DeltaNutrients–DrinkingWaterIssues vii June20,2017

A.1THESTATEWATERPROJECT.........................................................................................................................58

A.2NutrientConcentrationsintheDeltaandSWP.......................................................................................70

A.3CyanobacteriaTaxaMakeup............................................................................................................................76

A.4PotentialAlgalProductionofSourceWaters...........................................................................................77

DeltaNutrients–DrinkingWaterIssues viii June20,2017

List of Tables

Table1.StateWaterProjectFacilitiesandTargetOrganismsAddressedbytheCaliforniaDepartmentofWaterResourcesAquaticWeedandAlgalBloomControlPrograms(DWR2013)................................................................................................................................................................................19

Table2.USEPAAlgalToxin10‐DayDrinkingWaterHeathAdvisories(applicabletotapwater).....24

Table3.MicrocystisBiomassandMicrocystinConcentrationsinCliftonCourtForebay........................25

Table4.USEPAD/DBPRuleRequirementsforTOCRemoval...........................................................................29

List of Figures

Figure1.TheSacramento‐SanJoaquinDeltaandSWPMonitoringLocations..............................................4

Figure2.TheStateWaterProject.....................................................................................................................................6

Figure3.ContraCostaWaterDistrictDeltaWaterIntakes...................................................................................9

Figure4.TotalNConcentrationsintheSWPWatershed:2004–2010.........................................................11

Figure5.TotalPConcentrationsintheSWPWatershed:2004–2010..........................................................11

Figure6.TotalKjeldahlNitrogenandTotalPhosphorusatOldRiverIntake:2010–2014..................12

Figure7.TotalKjeldahlNitrogenandTotalPhosphorusatMiddleRiverIntake:2010–2014..........12

Figure8.MIBandGeosminConcentrationsatBanksPumpingPlant.............................................................16

Figure9.MIBandGeosminConcentrationsatCheck41ontheCaliforniaAqueduct..............................16

Figure10.MIBandGeosminConcentrationsatCheck66ontheCaliforniaAqueduct...........................17

Figure11.GeosminConcentrationsatCastaicLakeOutlet.................................................................................17

Figure12.MIBConcentrationsatCastaicLakeOutlet...........................................................................................18

Figure13.MIBandGeosminConcentrationsatLakeSilverwoodOutlet......................................................18

Figure14.MIBandGeosminConcentrationsatLakePerrisOutlet.................................................................19

Figure15.GeosminandMIBinContraCostaCanalatClyde:2010–2014..................................................21

Figure16.GeosmininMallardReservoir:2010–2014........................................................................................21

Figure17.MIBinMallardReservoir:2010–2014.................................................................................................22

DeltaNutrients–DrinkingWaterIssues ix June20,2017

Figure18.AlgalBiomassintheSouthBayAqueductatDelValleCheck7....................................................23

Figure19.TotalMicrocystininBarkerSlough..........................................................................................................26

Figure20.TotalMicrocystininCliftonCourtForebay...........................................................................................26

Figure21.TotalMicrocystininBanksPumpingPlant...........................................................................................26

Figure22.TotalMicrocystininDyerReservoir........................................................................................................26

Figure23.TotalMicrocystininLakeDelValleCheck............................................................................................27

Figure24.TotalMicrocystininSanLuisReservoiratPachecointake............................................................27

Figure25.TotalMicrocystininSanLuisReservoiratGianelliIntake.............................................................27

Figure26.TotalMicrocystininO’NeillForebayOutlet.........................................................................................27

Figure27.TotalMicrocystininPyramidLake...........................................................................................................28

Figure28.TotalMicrocystininCastaicLake.............................................................................................................28

Figure29.TotalMicrocystininLakeSilverwood.....................................................................................................28

Figure30.TotalCylindrospermopsininPerrisLake..............................................................................................28

Figure31.pHlevelsinSouthBayAqueductduring2016....................................................................................31

DeltaNutrients–DrinkingWaterIssues x June20,2017

DeltaNutrients–DrinkingWaterIssues 1 June20,2017

1.0 Introduction, Purpose, and Organization of the Review

1.1 BACKGROUND AND CONTEXT

TheSacramento–SanJoaquinRiverDelta(Delta)isanetworkofnaturalandengineeredchannelsandagriculturallowlandslocatedinNorthernCalifornia,formedbytheconfluenceoftheSacramentoandSanJoaquinRivers(seeFigure1).TheDeltaisacomponentoftheSanFranciscoEstuarysystemandisinfluencedbythetides,tovaryingdegrees,throughoutitsdomain.TheDeltaisakeycomponentoftheState’swaterresourcesystem;waterexportedfromtheDeltaservesmorethan25millionpeopleand4.5millionacresofirrigatedfarmlandsintheBayArea,theSanJoaquinValley,andSouthernCalifornia(DeltaStewardshipCouncil2013).Onaverage,approximately6.1millionacrefeet(MAF)ofwaterareexportedfromtheDeltaduringwetyearsandabout4.1MAFduringdryyears(DeltaStewardshipCouncil2013).TheCaliforniaStateWaterProject(SWP)andtheFederalCentralValleyProject(CVP)conveywaterfromtheSouthDeltatotheSanFranciscoBayArea,SanJoaquinValley,CentralCoast,andSouthernCalifornia.Additionally,theDeltaisvitalforthestate’seconomyandenvironmentasahometothousandsofresidentsaswellasanimportantagriculturalareaandacriticalhabitatforfish,birds,andwildlife.

TheDeltaiswidelyrecognizedasbeinginastateof“crisis”duetothecompetinganthropogenicdemandsforitsresources(DeltaPlan2013).TheDelta’swaterresourcesareneededforecosystemhealth,agriculture,fisheries,andmunicipalsupplies.Theconsequencesofthesecompetingdemandsincludehabitatdegradation,fragmentationandloss,highlymodifiedflowregimesandwaterlossesandwaterqualityimpairments,andnon‐nativespeciesinvasions.ThedischargeofpollutantstotheDeltaandtributarywatersfromurban,agricultural,andnonpointsourcesalsoposespotentialthreatstothemanybeneficialusesdesignatedfortheDelta.

In2009,theCalifornialegislaturepassedtheDeltaReformActcreatingtheDeltaStewardshipCouncil(Council).ThemissionoftheCouncilistoimplementthecoequalgoalsoftheReformActandprovideamorereliablewatersupplyforCaliforniawhileprotecting,restoring,andenhancingtheDeltaecosystem.TheCouncilwroteandadoptedaDeltaPlanin2013toimplementthesecoequalgoalswhichincludedawaterqualityrecommendationtoconsiderdevelopmentofnutrientobjectivesfortheDelta(WQR8.CompletionofRegulatoryProcesses,Research,andMonitoringforWaterQualityImprovement).NutrientsareamongthepollutantsdischargedtotheDeltafrommunicipal,industrial,agricultural,andothernonpointsources.ThisrecommendationaddressestheexcessnutrientsintheDeltathatareaprimaryconcernbecausethey,alongwithotherfactors,stimulatemacrophytegrowthandalgalbloomswhichcandisruptwatertreatmentprocesses,causetasteandodorproblems,andcontributetocyanotoxinproduction(DeltaStewardshipCouncil2013).AsnutrientsareoneofthepollutantgroupsbelievedtopotentiallycauseimpairmentstoDeltawaterquality,theStateWaterResourcesControlBoardandtheSanFranciscoBayandCentralValleyRegionalWaterQualityControlBoardshavebeenchargedwithdevelopingandimplementingaresearchplantodeterminetheneedforeithernumericornarrativenutrientwaterqualityobjectivesfortheDeltaandSuisunMarsh.

InresponsetotherecommendationintheDeltaPlan,theCentralValleyRegionalWaterQualityControlBoard(CentralValleyWaterBoard)hasembarkedonaDeltaNutrientResearchProgramtoaddresstheneedfornutrientwaterqualityobjectives.Inordertoprovideappropriatebackgroundregardingthecurrentunderstandingandknowledgegapsassociatedwithspecificnutrient‐relatedareasofinterest,andtoinformtheneedforfutureresearchintheDelta,workgroupswereformedwithlocalexpertleadershiptodevelopwhitepapersandrecommendationsforfutureresearchneedsonthefollowingtopics:

Cyanobacteria Macrophytes NutrientFormsandRatios DrinkingWaterConcerns ModelingScience

1.2 GOAL AND ORGANIZATION OF DRINKING WATER ISSUES LITERATURE REVIEW

ThisdocumentprovidesasynthesisofliteratureonthepotentialadverseimpactsofambientnutrientlevelsintheDeltaondrinkingwatersourcesintheDeltaandtheSWP.Asameanstogaininsightintothenutrient‐relatedissuesencounteredinout‐of‐Deltaconveyancestructures,reservoirs,andwatertreatmentfacilities,aworkshop1ontastesandodors,cyanobacteria,macrophytes,andotherfactorswasheldtoinformtheDrinkingWaterWorkgroupontheseissues.TheworkshoppresentersincludedcurrentandformeremployeesoftheMetropolitanWaterDistrictwhospecializeinunderstandingandattemptingtolimitalgaeandmacrophytebloomsthatimpactdrinkingwaterintheSWPanddownstreamreservoirs.Thisdocumentidentifiesdatagapswithinthecurrentbodyofknowledge,andsuggestsstudiesthatwouldprovideinformationtobridgethosegaps.Theliteraturereviewhasthreemajorobjectives:

1. ProvideabasicreviewofdrinkingwaterissuespresentintheDeltapotentiallyassociatedwithcurrentnutrientlevels;

2. ProvideadiscussionofassociatedimpactstoCalifornia’sdrinkingwaterresources,bothwithintheDeltaandindownstreamconveyanceandstoragefacilities;and

3. IdentifydatagapsandresearchneedstounderstandwhethercontrolofnutrientconcentrationsintheDeltawouldreduceexistingdrinkingwaterconcerns.

Thisreview,andtherecommendednextsteps,willcontributetotheDeltaNutrientsScienceandResearchPlanwhichwillidentifyscientificresearchneededtodeterminewhetherandhowtoproceedwiththedevelopmentofnutrientwaterqualityobjectivesfortheDelta.Thedocumentisorganizedasfollows:

1WorkshoptoIdentifyResearchProposals–TastesandOdors,Cyanobacteria,Macrophytes,andOtherFactors.WorkshopheldonFebruary24,2017,attheofficesofLarryWalkerAssociates,Davis,CA.

Section1:Introduction,Purpose,andOrganizationoftheReview

Section2:Nutrient‐RelatedDrinkingWaterIssues

Section3:FactorsInfluencingNutrient‐RelatedDrinkingWaterIssues

Section4:ManagementofIdentifiedIssues

Section5:DataGaps

Section6:RecommendationsforResearchandModelingPriorities

Section7:LiteratureCited

Figure 1. The Sacramento-San Joaquin Delta and SWP Monitoring Locations

2.0 Nutrient-Related Drinking Water Issues

2.1 DELTA NUTRIENTS BACKGROUND

2.1.1 Delta Hydrology

ThetwomajorsourcesoffreshwaterinflowtotheDeltaaretheSacramentoandSanJoaquinRivers(seeFigure1).Additionalflowscomefromtheeastsidetributaries:theMokelumne,Calaveras,andCosumnesRivers.TheSacramentoRiverprovidesapproximately75to85percentofthefreshwaterflowtotheDeltaandtheSanJoaquinRiverprovidesabout10to15percentoftheflow.Duringextremelywetyears,SacramentoRiverflowscanexceed100,000cubicfeetpersecond(cfs)atFreeport.TheflowsintheSanJoaquinRiveratVernalisaresubstantiallylowerthanflowsintheSacramentoRiver.PeakSanJoaquinRiverflowscanexceed50,000cfs,butflowsarenormallymuchlower.FlowsontheSacramentoandSanJoaquinriversarehighlymanaged.CentralValleyProject(CVP)andSWPreservoirsontheriversandtheirtributariesattenuatethehighlyvariablenaturalflows,capturinghighvolumeflowsduringshortwinterandspringperiodsandreleasingwaterthroughouttheyear.

WaterfromtheSacramentoRiverflowsintothecentralDeltaviaGeorgianaSloughandtheDeltaCrossChannel,whichconnectstheSacramentoRivertotheMokelumneRiverviaSnodgrassSlough(seeFigure1).TheDeltaCrossChannel(DCC)isoperatedbytheU.S.BureauofReclamation(Reclamation).TheDCCoperationsareregulatedtomeetmultipleneeds,includingfishmigration,Deltawaterquality,floodprotection,andflowintheSacramentoRiver.TheDCCisgenerallyclosedbetweenJanuaryandmid‐June,openbetweenmid‐JuneandOctober,andclosedinNovemberandDecember.FlowsofSacramentoRiverwaterthroughtheDCCimprovecentralDeltawaterqualitybyincreasingtheflowofhigherquality(lowersalinity,lowerorganiccarbon)SacramentoRiverwaterintothecentralandsouthernDelta.TherelativeimpactoftheDCCoperationsonwaterqualityatthesouthDeltapumpingplantsisgovernedbywaterprojectoperations,tidalaction,andflowsontheSanJoaquinRiver.

2.1.2 The State Water Project

TheSWPextendsfromthemountainsofPlumasCountyintheFeatherRiverwatershedtoLakePerrisinRiversideCounty.Figure2showsthemajorfeaturesoftheSWP.WaterfromthenorthDeltaispumpedintotheNorthBayAqueduct(NBA)attheBarkerSloughPumpingPlant.BarkerSloughisatidallyinfluenceddead‐endsloughwhichistributarytoLindseySlough.LindseySloughistributarytotheSacramentoRiver.ThepumpingplantdrawswaterfromboththeupstreamBarkerSloughwatershedandfromtheSacramentoRiver,viaLindseySlough.TheNBAservesasamunicipalwatersupplysourceforanumberofmunicipalitiesinSolanoandNapacounties.

InthesouthernDelta,waterentersSWPfacilitiesatCliftonCourtForebay(CliftonCourt),andflowsacrosstheforebayabout3milestotheH.O.BanksDeltaPumpingPlant(Banks),fromwhichthewaterflowssouthwardintheGovernorEdmundG.BrownCaliforniaAqueduct(CaliforniaAqueduct).WaterisdivertedintotheSouthBayAqueduct(SBA)atBethanyReservoir,1.2miles

Figure 2. The State Water Project

downstreamfromBanks.FromBethanyReservoir,waterflowsintheCaliforniaAqueductabout59milestoO’NeillForebay.TheforebayisthestartoftheSanLuisJoint‐UseFacilities,whichservebothSWPandfederalCVPcustomers.CVPwaterispumpedintoO’NeillForebayfromtheDelta‐MendotaCanal(DMC).TheDMCconveyswaterfromtheC.W.“Bill”JonesPumpingPlant(Jones)to,andbeyond,O’NeillForebay.SanLuisReservoirisconnectedtoO’NeillForebaythroughanintakechannellocatedonthesouthwestsideoftheforebay.AnintakeonthewestsideofthereservoirprovidesdrinkingwatersuppliestoSantaClaraValleyWaterDistrict.

WaterreleasedfromSanLuisReservoirco‐minglesinO’NeillForebaywithwaterdeliveredtotheforebaybytheCaliforniaAqueductandtheDMC,andexitstheforebayatO’NeillForebayOutlet,locatedonthesoutheastsideoftheforebay.O’NeillForebayOutletisthebeginningoftheSanLuisCanalreachoftheCaliforniaAqueduct.TheSanLuisCanalextendsabout100milestoCheck21,nearKettlemanCity.TheSanLuisCanalreachoftheaqueductservesmostlyagriculturalCVPcustomersandconveysSWPwaterstopointssouth.ThejunctionwiththeCoastalBranchoftheaqueductislocated185milesdownstreamofBanksandabout12milessouthofCheck21.TheCoastalBranchprovidesdrinkingwatersuppliestocentralCaliforniacoastalcommunitiesthroughtheCentralCoastWaterAuthorityandtheSanLuisObispoCountyFloodControlandWaterConservationDistrict.FromthejunctionwiththeCoastalBranch,watercontinuessouthwardintheCaliforniaAqueduct,providingwatertobothagriculturalanddrinkingwatercustomersintheserviceareaofKernCountyWaterAgency.

EdmonstonPumpingPlantisatthenorthernfootoftheTehachapiMountains.ThisfacilityliftsSWPwaterabout2000feetbymulti‐stagepumpsthroughtunnelstoCheck41,locatedonthesouthsideoftheTehachapiMountains.Aboutamiledownstream,theCaliforniaAqueductdividesintotheWestandEastBranches.TheWestBranchflows14milestoPyramidLake,thenanother17milestoCastaicLake,thedrinkingwatersupplyintakeoftheMetropolitanWaterDistrictofSouthernCalifornia(MWDSC)andCastaicLakeWaterAgency.PyramidLakehasacapacityof171,200acre‐feetandCastaicLakehasacapacityof323,700acre‐feet.

FromthebifurcationoftheEastandWestBranches,waterflowsintheEastBranchtohighdesertcommunitiesintheAntelopeValleyservedbytheAntelopeValleyEastKernWaterAgencyandthePalmdaleWaterDistrict.DrinkingwatersuppliesaredeliveredtoMWDSCandSanBernardinoValleyMunicipalWaterDistrictfromtwoDevilCanyonafterbaysdownstreamofSilverwoodLake,wherewateristransportedviatheSantaAnaPipelinetoLakePerris,whichistheterminusoftheEastBranch.MWDSCroutinelytakesasmallamountofwaterfromLakePerris.

AdetaileddescriptionoftheStateWaterProjectisprovidedinAppendixA.

2.1.3 Contra Costa Water District

TheContraCostaWaterDistrict(CCWD)isaCVPcontractorthatdivertswatersuppliesfromlocationsinthewesternandsouthernDelta.Figure3showsthelocationsoftheCCWDwatersupplyintakesintheDelta.CCWDdivertswaterunderitsCVPwaterrightsattheRockSloughIntakenearOakley,theOlderRiverIntakenearDiscoveryBay,andtheMiddleRiverIntakeonVictoriaCanal.DependingontheintakeandwherewaterisneededintheCCWDservicearea,the

waterisdivertedtointotheContraCostaCanalandconveyedtotreatmentplantsandreservoirslocatedthroughouteasternandcentralContraCostaCountyortoLosVaquerosReservoir.LosVaquerosReservoirstoredwaterisprimarilyusedforblendingintheContraCostaCanalforimprovedwaterquality.CCWDalsohasitsownMallardSloughIntakeinBayPoint,althoughdiversionsatthisintakeareunreliableduetohighsalinityatthispointofdiversion.

2.1.4 Nutrient Concentrations in the Delta and SWP

NutrientdatapresentedinthisreportweredrawnfromtheDepartmentofWaterResources(DWR)MunicipalWaterQualityInvestigation(MWQI)ProgramandfromtheDivisionofOperationsandMaintenance(O&M)waterqualitymonitoringprogram.ThesedatawereusedtoprovideageneralbackgroundonnutrientconcentrationsmeasuredintheDeltaandSWP.

Figure4presentsthetotalnitrogen(totalN)dataandFigure5presentsthetotalphosphorus(totalP)dataforthetributariestotheSacramento‐SanJoaquinDelta(Delta),CliftonCourt,andBanksfortheperiod2004–2010.TotalNandtotalPconcentrationsarelowattheAmericanRiverandtheSacramentoRiveratWestSacramento(WestSacramento)sites.ThereisanobservableincreaseinbothnutrientsattheSacramentoRiveratHood(Hood);however,theHoodconcentrationsofbothnitrogenandphosphorusaremuchlowerthanthosefoundintheSanJoaquinRiveratVernalis(Vernalis).AppendixAincludesfigureswhichshowtheseasonalandspatialvariabilityinnutrientconcentrationsatHood,Vernalis,BarkerSlough,andBanks.

NutrientconcentrationsincreaseconsiderablyintheSacramentoRiverbetweenWestSacramentoandHood,despitetheinflowofthehighqualityAmericanRiver,duetothedischargefromtheSacramentoRegionalWastewaterTreatmentPlantaswellasinputsfromagricultural,industrial,andurbanrunoffsources.ThemedianconcentrationsoftotalN(0.67mg/L)andtotalP(0.08mg/L)atHoodarestatisticallysignificantlyhigherthanthemedianconcentrationsoftotalN(0.29mg/L)andtotalP(0.05mg/L)atWestSacramento.TotalNandtotalPconcentrationsintheSanJoaquinRiverareconsiderablyhigherandmorevariablethanconcentrationsintheSacramentoRiver.ThemediantotalNconcentrationatVernalisof2mg/ListhehighestintheSWPsystem.ThemediantotalPof0.16mg/LcalculatedforVernalisistwicethelevelfoundatHood.

NutrientconcentrationsintheNBAarehigherthanintheSacramentoRiver.ThemediantotalNconcentrationis0.8mg/LandthemediantotalPconcentrationis0.18mg/L.TheSacramentoRiveristheprimarysourceofwatertoBarkerSlough,soitisevidentthatthelocalwatershedsuppliessomenitrogenandasubstantialamountofphosphorustotheNBA.Thereisextensivecattlegrazingandfarmingthroughoutthewatershed,andthereisagolfcourseintheupperpartofthewatershed;allpotentialsourcesofnutrients.

Figure 3. Contra Costa Water District Delta Water Intakes

AlthoughtheSacramentoRiveristheprimarysourceofwaterdivertedthroughBanksintotheSWPsystem,theSanJoaquinRiverisalsoamajorsourceofwatertoBanks;theSanJoaquinRiver’spercentcontributionvarieswithhydrologyandwaterprojectoperations.ThetotalNconcentrationatBanks(medianof0.88mg/L)isabout30percenthigherthanthemedianconcentrationof0.67mg/LatHood(Mann‐Whitney,p=0.0002)andthedataaremorevariable.ThemediantotalPconcentrationof0.10mg/LatBanksisslightlyhigherthanthe0.08mg/lmedianconcentrationcalculatedatHood(Mann‐Whitney,p=0.0046),withbothdatasetsshowingthesamevariability.Asdiscussedpreviously,themediantotalNconcentrationatVernalisismorethantriplethemedianconcentrationatHood,whereasthemediantotalPconcentrationisaboutdouble.ThismaypartiallyexplainwhythetotalNconcentrationsatBanksincreasemorethanthetotalPconcentrations;however,therearealsoin‐Deltasourcesofnutrientsincludingagriculturaldischarges,wastewatertreatmentplants,andurbanrunoff.Anothercomplicatingfactoristhatnutrientsarenotconservativeconstituents.

DatahavebeencollectedatanumberoflocationsalongtheCaliforniaAqueductfrom2004to2010(SeeAppendixA).NutrientconcentrationschangeverylittleaswaterflowsfromtheDeltathroughtheSBAandtheCaliforniaAqueduct.AslightincreaseintotalNisobservedmovingdownstreamintheAqueductfromCheck21toCheck41duetonon‐projectinflowsfromfourmajorsources(SemitropicWaterStorageDistrict,KernWaterBankAuthority,CrossValleyCanalinflows,andArvinEdisonCanalinflows(ArchibaldConsultingetal.,2012)).MediantotalNconcentrationsareabout1.0mg/LandmediantotalPconcentrationsareabout0.1mg/Lthroughoutthesystem,withtheexceptionoftheCastaicOutletandPerrisOutlet.ThemedianconcentrationsoftotalNandtotalParesubstantiallylowerattheCastaicOutlet.Algaluptakeandsubsequentsettlingofparticulatemattermayberesponsibleforthelowernutrientconcentrationsintheterminalreservoirs.

Figure 4. Total N Concentrations in the SWP Watershed: 2004 – 2010

Figure 5. Total P Concentrations in the SWP Watershed: 2004 – 2010

West Sacramento

American

Mokelumne

Calaveras

Vernalis

Clifton C

West Sacramento

American

Mokelumne

Calaveras

Vernalis

Clifton C

CCWDimplementsawaterqualitymonitoringprogramthatincludesmonitoringfornutrientsatCCWDintakefacilitiesandreservoirs.AttheOldRiverIntaketheaverageTotalKjeldahlnitrogenconcentrationwas0.1mg/L(rangeofnon‐detect(ND)to0.8mg/L),andtheaveragetotalphosphorousconcentrationwas0.07mg/L(rangeofNDto0.18mg/L)(seeFigure6).AttheMiddleRiverIntaketheaverageTotalKjeldahlnitrogenconcentrationwas0.2mg/L(rangeofNDto2.2mg/L),andtheaveragetotalphosphorousconcentrationwas0.1mg/L(rangeofNDto1.0mg/L)(seeFigure7).

Figure 6. Total Kjeldahl Nitrogen and Total Phosphorus at Old River Intake: 2010 – 2014

Figure 7. Total Kjeldahl Nitrogen and Total Phosphorus at Middle River Intake: 2010 – 2014

2.2 PROBLEMS ASSOCIATED WITH HIGH NUTRIENT LEVELS AND OTHER ENVIRONMENTAL FACTORS

DrinkingwateragenciesthattakewaterfromtheDeltaviatheSWPandCVPfacechallengesduetocyanobacteriaharmfulalgalblooms(cyanoHABs)andmacrophytegrowththatoccurinSWPandCVPconveyancesandstoragefacilities(seeFigure2),asdiscussedfurtherinSection3.0.Whiletherearemanyfactorswhichcanstimulatealgaeandmacrophytegrowth,nutrients,temperature,light,residencetime(particularlyinreservoirs),andwaterclarityareconsideredmajordrivers.

Traditionally,ithasbeenassumedthathighnutrientconcentrationswereresponsibleforcausingperiodiclowdissolvedoxygenlevelsintheStocktonDeepWaterShipChannelandseveraldeadendsloughsonthesouthernandeasternsideoftheDeltaduetothestimulationofalgalgrowth,followedbysenescenceandbreakdownbybacteria(LeeandJones‐Lee2006).Incontrast,itwasalsoassumedthathighnutrientlevelsdidnotencourageprimaryproductivityinsomeregionsoftheDeltawithhighturbidityandlowlight(AlpineandCloern1992,TetraTech2006).However,recenthypothesesdescribedintheDraftNutrientStrategyfortheDelta(CVRWQCB2013)postulatethathighnutrientlevelsmayshiftalgalspeciescomposition,decreasedissolvedoxygenconcentrations,causetasteandodorissues,andincreaseproductivityofblue‐greenalgae(i.e.,cyanobacteria)andnon‐nativemacrophytes(i.e.,waterhyacinth(Eichhorniacrassipes)andBrazilianwaterweed(Egeriadensa)).Therecommendationsformonitoring,research,andmodelingprovidedinSection6.0ofthisdocumentareadvancedtosupportthetestingofthesevarioushypothesestodetermineifnutrientsareofissueintheDeltaanddownstreamconveyanceandstoragefacilitiesastheyrelatetoalgalandmacrophytegrowthandcommunitycomposition.

Elevatedconcentrationsofnitrate(>10mg/L)canalsobetoxictohumansandareassociatedwithmethemoglobinemia,alsoknownas“blue‐baby”syndrome,whichoccursasnitratesinthebodyareconvertedtonitrite,whichreactwithhemoglobininredbloodcellstoformmethemoglobin,whichaffectstheabilityofbloodtocarryoxygenaroundthebody(Knobelochetal.2000).However,ambientnitratelevelsintheDeltahavenotbeenobservedtoapproachtheprimaryMCLof10mg/l.Therefore,themajorDrinkingWaterissuesfacingtheDeltawherenutrientsmaybeafactorcontributingtoaproblemrelatetotherecentchangesincyanobacteriaandmacrophyteprevalenceandcommunitycomposition.ThefollowingsectionbrieflydiscussesthedrinkingwaterchallengesasaresultofcyanobacteriaandmacrophytegrowthintheDeltaanddownstreamsystems,includingtasteandodorissues,cyanotoxinproduction,increaseddissolvedorganiccarbon,diurnalpHswings,andfilterandpumpclogging.

2.3 ALGAE AND MACROPHYTE PROBLEMS IN DRINKING WATER SUPPLIES

2.3.1 Nuisance Algae and Harmful Cyanobacteria Blooms

ACyanobacteriaWorkgroup,convenedbytheDeltaNutrientScienceandResearchProgram,reviewedliteratureforthepurposeofdeterminingwhichpresentandfuturefactorsaremostlikelyassociatedwithcyanobacteriaharmfulalgalbloom(cyanoHABs)prevalenceintheDeltaandconcluded,basedonculturestudies,thatthereisnosignificantorconsistentchangeingrowthratesofcyanobacteriawithchangeinnitrogensourceornitrogentophosphorusratioswhennutrient

concentrationsarenotlimiting(Tilmanetal.1982,Tettetal.1985,Reynolds1999,SakerandNeilan2001,Roelkeetal.2003,SundaandHardison2007).BasedoninvestigationscarriedoutintheDelta,nutrientratioshavenotbeenobservedtovaryfrompre‐bloomtobloom,indicatingthatnutrientsarenotlimitingthroughouttheentiretyofthesummerseason(Lehmanetal.2008,Mionietal.2012).TheCyanobacteriaWorkgroupsuggestedthatwhilecyanoHABsobservedintheDeltalikelywerenotduetochangesinnutrientconcentrationsortheirratios,thedurationandmagnitudeofcyanoHABsareinfluencedbytheavailablenutrientsupplyandtherefore,areductioninnutrientscouldreducethedurationandintensityofsuchblooms(BergandSutula2015).Furthermore,althoughnutrientswerenotfoundtolimitgrowthrates,theformofnitrogen(i.e.,ammonia,ammonium,nitrate,nitrite)andnitrogentophosphorusratioshavebeenpostulatedtohaveaneffectonfoodwebdynamicsandcomposition(Dugdaleetal.2007,Glibertetal.2011).

Taste and Odors

Certaincyanobacteriaandactinomycetebacteriaproducechemicalcompoundsthatarenotremovedinconventionalwatertreatmentprocessesandarecapableofcausingunpleasanttastesandodors(T&O)indrinkingwater.T&OincidentsoccurthroughouttheSWPinthetreatedwaterandarecommonlyassociatedwithgeosminand2‐methylisoborneol(MIB)thatareproducedbybenthicandplanktoniccyanobacteria.GeosminandMIBarenon‐toxicorganiccompoundsthatimpartanearthy,muddy,musty‐typeodor/tasteinwaterthatmanyfindunacceptable.Theabilityofindividualstodetectthesechemicalsvaries,butthegeneralpopulationcandetecteithercompoundataconcentrationofabout10ng/L(nanogramsperliter,orpartspertrillion),andsensitiveindividualscandetectevenlowerconcentrations.Asaresult,somewateragencieshaveinstalledadvancedtreatmentprocesses,suchasozonationandpowderedactivatedcarbon,toreducethelevelsoftheseT&Ocompoundsintreateddrinkingwater.

Strainspecificitymakesitdifficulttodetermineapriorithatoccurrenceofaparticulartaxonintheplankton(orbenthos)ofadrinkingwatersourcewillleadtoT&Oevents.Typically,thestrainsresponsibleforT&Oissuesarenotthemostdominantmembersofthecommunityandtherefore,oftengomisdiagnosed(SeeSectionA.3inAppendixA).Forexample,inCastaicLake,aterminalreservoiroftheSWPinsouthernCalifornia,aT&Oeventin1993wasblamedonastrainofPseudanabaenaintheplankton(IzaguirreandTaylor1998).However,PseudanabaenaiscommoninsouthernCaliforniawaters,andmoststrainsisolatedovera23‐yearperiodhavenotcausedT&Oproblems.AccordingtoIzaguirreandTaylor(1998),becauseMIBproductionisararephenomenoninthisgenus,itisdifficulttopredictT&Oeventsinvolvingtheorganism,orthoseinvolvingothertaxasuchasSynechococcus(Izaquirreetal.1984),Hyella,andOscillatorialimosa(IzaguirreandTaylor1995).Thereisalargeliteraturedescribingeffortstoisolateandidentifystrainsofalgae,cyanobacteria,andotherT&Ocompoundproducingorganisms.

BenthiccyanobacteriaareresponsibleformostoftheT&OeventsreportedintheliteratureinterminalreservoirsreceivingwaterfromtheSWP.AlmostalloftheT&OeventsinDiamondValleyLakeareassociatedwithfilmsofbenthiccyanobacteria(OscillatoriaorPhormidiumspp.),whichgrowonthesidesofthereservoirandonthedam.ThebenthiccoloniesinDiamondLakeformonsediments3‐17mdeep(IzaguirreandTaylor2007),usuallyinlatesummer.Thisindicatesthattheyarefrequentlypositionednearthethermocline,wheretheywouldhavegreateraccessto

diffusivefluxesofnutrientsreleasedatthesediment/waterinterfaceduringsummerstratification.MIBproducingstrainsofOscillatoriathathavebeenisolatedfromothersouthernCaliforniareservoirs(LakeMathews,LasVirgenesReservoir,LakeBard,LakeSkinner,andSilverwoodLake)arealsobenthicforms(IzaguirreandTaylor2007).Therangeofdepthsandthus,totalsurfaceareaavailabletothesecolonieswillvarypositivelywithwaterclarity.

SampleshavebeencollectedfromuntreatedwaterinSWPfacilitiesbytheDepartmentofWaterResources(DWR)andanalyzedfortheT&Oproducingcompounds,MIBandgeosmin,since2000whenthetechnologytoreadilyanalyzeforthesecompoundsbecameavailable.Figure8throughFigure14showconcentrationsofMIBandgeosminatvariouslocationsalongtheCaliforniaAqueduct,BanksPumpingPlant,andlakeoutletswithpeakconcentrationstypicallyoccurringinthesummermonths.BenthiccyanobacteriaaretheprimarysourcesofT&OcompoundsintheDeltaandinCliftonCourtForebay(DWR2013).ThehighlevelsofMIBandgeosminaretransportedtotheSouthBayAqueduct(SBA)anddowntheCaliforniaAqueduct.MIBandgeosminarealsogeneratedbybenthiccyanobacteriaintheCaliforniaAqueduct,theCoastalBranchandtheEastBranchoftheCaliforniaAqueduct(DWR2013).MIBandgeosminarebothfrequentlypresentathighconcentrationsintheEastBranchoftheaqueduct.Themaximumconcentrationsrecordedwere240ng/LofMIBinMay2003and396ng/LofgeosmininJuly2012(ArchibaldConsultingetal.,2012).PlanktoniccyanobacteriaareresponsibleforT&OproblemsinSilverwoodLake,LakePerris,PyramidLake,andCastaicLakeinSouthernCalifornia(DWR2013)whereconcentrationsreachedashighas1µg/Linsomelocations(SeeFigure11throughFigure14).DWRusesavarietyofaquaticpesticidesintheSWPaqueductsandreservoirstocontrolthesecyanobacteria,asdoestheMetropolitanWaterDistrictofSouthernCaliforniainitsreservoirsthatstoreSWPsupplies.

Figure 8. MIB and Geosmin Concentrations at Banks Pumping Plant

Figure 9. MIB and Geosmin Concentrations at Check 41 on the California Aqueduct

Geosmin

Figure 10. MIB and Geosmin Concentrations at Check 66 on the California Aqueduct

Figure 11. Geosmin Concentrations at Castaic Lake Outlet

Geosmin

Figure 12. MIB Concentrations at Castaic Lake Outlet

Figure 13. MIB and Geosmin Concentrations at Lake Silverwood Outlet

Geosmin

Figure 14. MIB and Geosmin Concentrations at Lake Perris Outlet

AreasoftheSWPandtheorganismstargetedbytheDWRAquaticWeedandAlgalBloomControlProgramsareshowninTable1.

Table 1. State Water Project Facilities and Target Organisms Addressed by the California Department of Water Resources Aquatic Weed and Algal Bloom Control Programs (DWR 2013).

State Water Project Facilities Macrophytes Algae

South Bay Aqueduct Unspecific T&O-producing cyanobacteria, Melosira varians, Cladophora sp.

Clifton Court Forebay

Egeria densa Potamogeton pectinalus Myriophyllum spicatum Ceratophyllum demersum Potamogeton nodosus Potamogeton crispus

T&O-producing cyanobacteria

Patterson Reservoir Unspecific Microcystis spp. Cladophora sp.

Dyer Reservoir Unspecific T&O-producing cyanobacteria, Aphanizomenon flos-aquae Anabaena sp.

Geosmin

State Water Project Facilities Macrophytes Algae

O’Neill Forebay Potamogeton sp. Potamogeton pectinalus L. Stuckenia striata

Unspecific

Coastal Branch Aqueduct Zannichellia palustris L. Potamogeton pectinalus

T&O-producing cyanobacteria, Cladophora sp.

East Branch Aqueduct Unspecific

T&O-producing attached cyanobacteria: Phormidium sp. Oscillatoria sp.

Pyramid Lake Ceratophyllum demersum Myriophyllum spicatum Stuckenia striata

T&O-producing cyanobacteria, Microcystis sp., Gloeotrichia sp., Anabaena sp.

Castaic Lake Unspecific T&O-producing attached and planktonic cyanobacteria, diatoms

Silverwood Lake Unspecific Anabaena lemmermannii

Lake Perris Unspecific

T&O-producing cyanobacteria, Synechococcus sp. Pseudanabaena sp. Anabaena sp.

Quail Lake Unspecific T&O-producing cyanobacteria, Microcystis sp., Gloeotrichia sp., Anabaena sp.

CCWDalsomonitorsfortasteandodorcompoundsintheirfacilitiesincludingtheContraCostaCanalandreservoirs.Monitoringduring2010–2014intheContraCostaCanalnearthecommunityofClyde,whichisalocationinthecanalafterallwatersourceshaveblended,foundgeosminlevelsthatrangedfromNDto80ng/L,withanaverageof5ng/L.MIBconcentrationsrangedfromNDto81ng/L,withanaverageof8.4ng/L(seeFigure15).CCWD’sMallardReservoiralsoexperiencesperiodicalgalbloomsandelevatedlevelsofgeosminandMIB.MonitoringinMallardReservoirduring2010–2014foundconcentrationsofgeosminrangingfromNDto2,200ng/L,withanaverageof43ng/L(seeFigure16).MIBconcentrationsatMallardReservoirrangedfromNDto29ng/L,withanaverageof2.5ng/L(seeFigure17).

Figure 15. Geosmin and MIB in Contra Costa Canal at Clyde: 2010 – 2014

Figure 16. Geosmin in Mallard Reservoir: 2010 – 2014

Figure 17. MIB in Mallard Reservoir: 2010 – 2014

Filter clogging

Algaeandmacrophytescancauseclogging,pumpingfailure,andtreatmentissuesduringwatertreatmentduetohighconcentrationsoftotalsuspendedsolids(TSS)andanoverabundanceofplanttissue.FiltercloggingalgaeoccurthroughouttheSWP,buttheyareparticularlytroublesomeintheSBA.Thehighconcentrationsofnutrients,combinedwithshallowcanaldepth,abundantsunlight,andwarmwatertemperaturesduringthespring,summer,andfallmonthsleadstoexcessivealgalgrowthintheSBA.ThiscreatesanumberoftreatmentchallengesfortheSBAContractorsandothers.Abenthicdiatom,Melosiravarians,andabenthicfilamentousgreenalga,Cladophorasp.,aretheprimaryalgaethatleadtofiltercloggingandreducedfilterruntimesatSBAwatertreatmentplants.DWRhassetalgalabundancethresholds(algalfluorescence>200unitsandalgalbiomass>5,000mg/m3)fortheSBAthatwhenexceededleadtotheapplicationofalgaecides(DWR2013).

TheprimarymechanismforcontrollingalgalgrowthintheSBAisbyapplicationofcoppersulfate,asthistreatmenthasproventobeaneffectivealgalcontrolmeasure.CoppersulfateisappliedeverytwotofourweeksfromMarchuntilOctoberorNovember,dependinguponwatertemperaturesandalgalconditions.Othercontrolmeasures,suchaslightlimitation,areintheirearlystagesofdevelopmentandtherefore,havenotbeenemployedasaroutinemethodtolimitalgalgrowth.AsshowninFigure18,algalbiomasshasexceeded5,000mg/m3almosteverysummersincedatacollectionbeganin2011,evenwithfrequentapplicationofcoppersulfate.

Figure 18. Algal Biomass in the South Bay Aqueduct at Del Valle Check 7

Cyanobacteria (Microcystis) and associated toxin-producing algae

MicrocystisaeruginosawasfirstdetectedintheDeltaintheeasternStocktonDeepWaterShipChannelinSeptember1999.IthasbloomedeveryyearduringthelatesummerandearlyfallthroughoutthecentralandsouthernDeltasinceitsinitialdetection.Microcystisspp.hasbeenfoundinCliftonCourtForebay;BanksPumpingPlant;DyerReservoir,PattersonReservoir,andDelValleCheck7ontheSBA;andtheGianelliintakeinSanLuisReservoirduringthelastthreeyears.Microcystisproducesmicrocystin,apotenthepatoxin(livertoxin).Otheralgalspecies,suchasAnabaena,Aphanizomenon,andPlanktothrixthatproducealgaltoxins(USEPA2012and2015a)havealsobeenfoundatanumberoflocationsintheSWP.SimilartothecyanobacteriawhichproduceT&Ocompounds,toxinproducingcyanobacteriaarenotalwaysthemostdominantmemberofthenaturalcommunityandcansometimesrepresentaverysmallproportionofthebiomass,butstillproduceasignificantconcentrationoftoxins(e.g.,seeAppendixA).

Therearecurrentlynostateorfederaldrinkingwaterstandardsformicrocystins;however,theWorldHealthOrganizationreleasedaprovisionalguidelineof1.0µg/Lformicrocystin‐LRindrinkingwaterin1998.TheUnitedStatesEnvironmentalProtectionAgency(USEPA)addedcyanobacteriaandcyanotoxinstotheCandidateContaminantList2(CCL)in1998,2005,and2009.CyanotoxinsarealsoonthedraftCCL4(2015).USEPApublished10‐daydrinkingwaterhealth

2TheContaminantCandidateListisalistofdrinkingwatercontaminantsthatareknownoranticipatedtooccurinpublicwatersystemsandarenotcurrentlysubjecttoEPAdrinkingwaterregulations.

10,000

15,000

20,000

25,000

30,000

35,000

Biomass,mg/m

advisoriesformicrocystinsandcylindrospermopsininJune2015(USEPA2015b).Healthadvisoriesdescribenon‐regulatoryconcentrationsofdrinkingwatercontaminantsatorbelowwhichadversehealtheffectsarenotanticipatedtooccuroverspecificexposuredurations(e.g.,10‐days).Table2presentstheUSEPAhealthadvisories.

Table 2. US EPA Algal Toxin 10-Day Drinking Water Heath Advisories (applicable to tap water)

Age Group Microcystins (µg/L) Cylindrospermopsin (µg/L)

Children, Six Years and Younger 0.3 0.7

Older Children and Adults 1.6 3.0

DWRinitiatedmicrocystinmonitoringinSWPfacilitiespriortotreatmentin2006.Between2006and2012,dissolvedmicrocystinwasdetectedinafewsamplesatlevelsrangingfrom<1.0to1.7µg/L.In2013,DWRchangedlaboratoriesandmeasurementmethodology.Thenewmethodmeasurestotalmicrocystins(dissolvedandparticulate),includingthemicrocystincontainedinalgalcells.Thisresultedinmorefrequentandhigherconcentrationdetectedatmorelocations.MicrocystinhasbeendetectedinBarkerSloughattheNorthBayAqueductintake,CliftonCourtForebay,BanksPumpingPlant,DyerReservoirontheSBA,theGianelliandPachecointakesinSanLuisReservoir,theO’NeillForebayOutlet(Check13)ontheCaliforniaAqueduct;andinPyramidLake,CastaicLake,andSilverwoodLakeinSouthernCalifornia(seeFigure19throughFigure30).

Table3presentsMicrocystisbiomassandmicrocystindataforCliftonCourtForebay,theforebayfortheBanksPumpingPlantintheSouthDelta,duringtheperiodJuly2013toAugust2015.ThistablepresentsdataforthedatesthateitherMicrocystisbiomassormicrocystinwasdetected.Notably,botharenotalwaysdetectedonthesamedate.TheUSEPA10‐dayDrinkingWaterHealthAdvisoryformicrocystinforyoungchildrenwasexceededninetimesinambientsamplesandtheadultlevelwasexceededtwiceintheCliftonCourtForebayambientsamples(seeTable3).

WithreferencetoFigure19throughFigure29,thehighestmicrocystinconcentrationswerefoundintheSWPreservoirs.ConcentrationsinsamplescollectedatseverallocationsanddepthsinPyramidLakerangedfrom0.23to81.5µg/Linthesummerof2015.SilverwoodLakehadconcentrationsrangingfrom0.30to40µg/Linthesummerof2013.SanLuisReservoirhadconcentrationsrangingfrom0.30to9.8µg/LattheGianelliintake,and0.80to6.5µg/LatthePachecointakein2013.ManyoftheseambientsamplesexceededtheUSEPAHealthAdvisories(applicabletotapwater)forbothchildrenandadults.

DWRstartedsamplingforcylindrospermopsinin2012.Samplesarecollectedonlywhenalgaeknowntoproducethistoxinarepresent.CylindrospermopsinhasonlybeendetectedinLakePerrisinSouthernCaliforniawheretheconcentrationsrangedfrom0.10to0.19µg/Lin2015(seeFigure30).TheseconcentrationsarebelowtheUSEPAHealthAdvisoriesforthetoxinpresentedinTable2.

Table 3. Microcystis Biomass and Microcystin Concentrations in Clifton Court Forebay.

Date Microcystis

Biomass, mg/m3 Percent of Total

Biomass Microcystin,

µg/L(1)

07/22/13 7.9 42.5

08/05/13 0.8 4.9

09/16/13 0.30

11/12/13 86.5 91.9

11/18/13 115.0 98.7

06/23/14 0.19

07/07/14 112.50 28.45 2.98

07/22/14 1.11

08/04/14 0.46

08/18/14 200.9 85.4 0.64

09/02/14 23.0 9.4 2.17

09/15/14 1.30

09/22/14 257.5 49.4

09/29/14 0.41

10/13/14 0.22

11/17/14 8.1 10.0

07/06/15 0.37

08/10/15 0.17 1 Bolded values exceed US EPA Algal Toxin 10-Day Drinking Water Heath Advisories of 0.3 µg/L for children 6 years and younger.

Figure 19. Total Microcystin in Barker Slough

Figure 20. Total Microcystin in Clifton Court Forebay

Figure 21. Total Microcystin in Banks Pumping Plant Figure 22. Total Microcystin in Dyer Reservoir

Health Advisory Children

Health Advisory Adults

No Potential Toxin Producers

Figure 23. Total Microcystin in Lake Del Valle Check Figure 24. Total Microcystin in San Luis Reservoir at Pacheco intake

Figure 25. Total Microcystin in San Luis Reservoir at Gianelli Intake Figure 26. Total Microcystin in O’Neill Forebay Outlet

Health AdvisoryChildrenHealth AdvisoryAdultsNo Potential ToxinProducers

Figure 27. Total Microcystin in Pyramid Lake

Figure 28. Total Microcystin in Castaic Lake

Figure 29. Total Microcystin in Lake Silverwood Figure 30. Total Cylindrospermopsin in Perris Lake

/LHealth Advisory ChildrenHealth Advisory AdultsNo Potential Toxin Producers

Dissolved Organic Carbon Production

AmbientnutrientlevelsintheDeltacancauseanincreaseintotalanddissolvedorganiccarbonconcentrationsasaresultofincreasedprimaryproductivity.Increasedproductivitycausesthereleaseoforganiccompoundsintothedissolvedorganiccarbonpool,asdoesthedeathanddecompositionofaquaticplantsandalgae.Dissolvedorganiccarbonisadrinkingwaterconcernprimarilyduetotheformationofcarcinogenicbyproductsthatareformedduringdisinfectionatawatertreatmentfacility(TetraTech2006).Chlorine,whichisaddedtodisinfectdrinkingwater,reactswithdissolvedorganiccarbontoformcompoundssuchastrihalomethanesandhaloaceticacids(generallyreferredtoadisinfectionbyproductsorDBPs)whicharebothknowncarcinogens(Flecketal.,2004).Theamountoforganiccarbonthatmustberemovedbyawatertreatmentplantisbasedontheconcentrationsoftotalorganiccarbon(TOC)andalkalinityinthesourcewater,asprescribedintheUSEPAComprehensiveDisinfectantsandDisinfectionByproductRules(Stage1andStage2(D/DBPRule))–seeTable4.AlgalproductionintheSWPfacilitiesresultsinhigherconcentrationsoftotalorganiccarboninthesystem.Currently,coppersulfateadditionistheonlycontrolmeasureusedtomanagealgalgrowth.TherelativecontributionfromtheDeltaandfromprimaryproductionintheSWPsystemisnotknown.

Table 4. US EPA D/DBP Rule Requirements for TOC Removal.

Subpart H systems1 that use conventional filtration treatment are required to remove specific percentages of organic materials, measured as total organic carbon (TOC) that may react with disinfectants to form DBPs. Removal must be achieved through a treatment technique (enhanced coagulation or enhanced softening) unless a system meets alternative criteria. Systems practicing softening must meet TOC removal requirements for source water alkalinity greater than 120 mg/L as CaCO3.

Source Water TOC (mg/L)

Source Water Alkalinity, mg/L as CaCO3

0-60 >60 to 120 >120

> 2.0 to 4.0 35.0% 25.0% 15.0%

> 4.0 to 8.0 45.0% 35.0% 25.0%

> 8.0 50.0% 40.0% 30.0%

1. Subpart H systems are public water systems using surface water or ground water under direct influence of surface water as a source that are subject to the requirements of Subpart H of 40 CFR Part 141 (40 CFR 141.3).

For additional information see: https://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=P100C8XW.txt

ThedirectcontrolofTOCandDOClevelsintheDeltawasconsideredindetailaspartofanextensivestakeholdercollaborativeknownastheCentralValleyDrinkingWaterPolicyworkgroupintheperiodfrom2002through2012.ThateffortculminatedinfindingsthatambientTOCandDOClevelswerenotexpectedtoincreaseatdrinkingwaterintakesinthenearfutureandthatadditionalwatertreatmentwouldnotberequiredtoaddressexistingTOCandDOClevelsunderthecurrentSafeDrinkingWaterActregulatoryrequirements(CentralValleyDrinkingWaterPolicyWorkgroup2012).

Diurnal Swings in pH

WideswingsinpHperiodicallyoccurintheSBA,asshownFigure31.ExcursionsofpHabovetheupperlimitoftheUSEPASecondaryMaximumContaminantLevel(MCL)of8.5standardunits(s.u.)fortheparameterwereobservedduringMay,June,September,November,andDecember2016.IncreasesinpHintheSBAaremostlikelyaresultofphotosyntheticremovalofcarbondioxide(CO2)fromthewatercolumnalongthelengthoftheopencanal,primarilybyalgae.ThesepHexcursionsareproblematicfortheSBAContractorsbecausethepHofthetreatmentplantinfluentmustbeadjustedtobewithinapHrangeof6.5–8.5standardunits(s.u.)forthedrinkingwatertreatmentprocesstomeetUSEPAsecondarystandards3forpHandtheSacramento‐SanJoaquinBasinPlan4objectivesandtoeffectivelydisinfectthewater.In2016,pHdatacollectedintheSBAexceededapHof8.5ontwo(2)separateoccasions.TrackingrapidpHchangesandadjustingacidfeedmakesitdifficulttomeetwatertreatmentregulationsandincreasestreatmentcosts.TreatmentcostsincreasebecauseacidisaddedtolowerthepHoftherawwatergoingintotheplantandthenmustbesubsequentlyoffsetbytheadditionofabasetoraisethepHofthefinishedwaterleavingtheplanttomeettherequirementsoftheLeadandCopperRule.

Solids Production

Wateragenciesmustuseadditionalquantitiesofchemicals,suchasferricchloride,alum,andpolymersinthewatertreatmentprocesstoremovealgaefromthesourcewater.Thisproducesgreaterquantitiesofsolidsinadditiontotheoverabundanceofplanttissuethatmustbedisposedoftoavoidcloggingandpumpingfailure,resultinginhighersolidsdisposalcosts.

2.3.2 Macrophytes

TheMacrophyteWorkgroupcametonoconclusionregardingtheeffectofnutrientsintheDeltaontriggeringorincreasingnon‐nativemacrophyteexpansionacrosstheDeltainrecentyears.TheexpansionofinvasivemacrophytesintheDeltaobservedwhencomparingtheresultsoftwomappingeventsin2008and2014cannotbelinkedtoachangeinambientnutrientconcentrations,asanevaluationofnutrientsintheDeltafrom2004–2014foundnoobvioustrendsinammonium,nitrate,phosphate,totalN,ortotalPconcentrationsacrossmultipleDeltamonitoringlocations(LWA2015).Tothisend,theMacrophyteWorkgroupconcludedthattheexpansionofinvasivemacrophytesinrecentyearscannotbelinkedtochangesinwatercolumnnutrientconcentrationsacrosstheDeltaduringthesameperiodandsuggestedthatotherfactorsbesidesnutrientsmightbecontributingtotheextensiveplantgrowth(BoyerandSutula2015).

3https://www.epa.gov/dwstandardsregulations/secondary‐drinking‐water‐standards‐guidance‐nuisance‐chemicals

4http://www.waterboards.ca.gov/centralvalley/water_issues/basin_plans/2016july_1994_sacsjr_bpas.pdf

Figure 31. pH levels in South Bay Aqueduct during 2016

Obstruction of Conveyance and Pumping Facilities

ExcessivegrowthofmacrophytesandalgaecreatewaterconveyanceproblemsatanumberoflocationsintheSWP.MacrophyteaccumulationcanbesosevereatBanksthatpumpingisrestrictedorhalted.Duringcertainperiods,upto20cubicyardsofmacrophytesareremovedeachdayfromthetrashracksatBanks.MacrophytesalsocreatemajoroperationalproblemsinO’NeillForebay,theCaliforniaAqueduct,andtheCoastalBranch.MacrophytesarealsopresentinthelittoralzoneofthefourSouthernCaliforniaSWPreservoirs.DWRexpendsasignificantamountoftimeandmoneycontrollingmacrophytesintheSWP.Copperproductsareusedinmanylocations,althoughtheyhavenotbeenusedsince2006inCliftonCourtduetopotentialimpactsonthreatenedandendangeredspecies.MechanicalharvestingisusedinCliftonCourtForebayandO’NeillForebayandsomesectionsoftheaqueductarescrapedbydraggingalargechainalongtheaqueductlining.

3.0 Factors Influencing Nutrient-Related Drinking Water Issues

ThefollowingsectionprovidesinformationpertainingtothefactorsthatmayinfluencethecyanobacteriaandmacrophyteprevalenceproblemswithintheSWPidentifiedinSection2.0.TheinformationpresentedbelowwastakenfromthewhitepapersproducedbytheCyanobacteriaandMacrophyteWorkgroups.

3.1 LIGHT/SOLAR IRRADIANCE

Allphotosyntheticorganismspossessacharacteristicphotosynthesis‐irradiancerelationshipwheretherateofphotosynthesisincreaseswithincreasedirradianceuptosomepointwherethelight‐harvestingcomplexofthephotosystembecomesoverwhelmedandphoto‐inhibition(i.e.,adeclineinphotosyntheticrate)occurs.Cyanobacteriahavecarotenoidpigmentsintheirphotosystemsthatprotectthemagainstphoto‐inhibitionatagivenirradiance,ascomparedtoaphotosyntheticorganismlackingsuchprotectivepigments(Huismanetal.1999,Reynolds2006).

Microcystisgrowthispooratlowandmixedlight,butgrowsveryefficientlyathighirradiances;especially,thosespeciesofMicrocystisthatproducetoxins(Huismanetal.2004,Reynolds2006,Careyetal.2012).Microcystisalsoshowspositivebuoyance,whichallowsittogrownearthewatersurfaceinpoorlymixedconditions.PhytoplanktonthatshowlessbuoyancycanbecomeshadedoutbysurfacegrowthsofMicrocystisunderlowmixedconditions(Careyetal.2012).Otherspeciesofcyanobacteria,includingCylindrospermopsisraciborskiiandPlanktothrixsp.aregoodcompetitorsatlowlightlevelsandgrowwellwithinthewatercolumnunderlowirradiances.C.raciborskiialsogrowswellathighirradiances,makingitwell‐suitedtoproduceharmfulcyanobacterialblooms(cyanoHABs)underavarietyofenvironmentalconditions.

LightconditionsintheDeltaaregenerallyadequateforfloatingmacrophytes,suchasE.crassipes(waterhyacinth).Attenuationofphotosyntheticallyactiveradiation(PAR,wavelengthsof400–700nm)inthewatercolumnbysuspendedparticles,includingphytoplankton,canlimitphotosynthesisofsomesubmersedmacrophytes.StudiesofE.densa(Brazilianwaterweed)growthunderdifferentlightconditionsshowthesubmersedmacrophytetohavevaryingresponsestochangesinirradiance,withonestudyshowingthemacrophytetohavelowerbiomassunderlowlightlevelsascomparedtohigherlevels(BorgnisandBoyer,unpublisheddata),andanotherstudyshowinganincreaseinbiomassatlowlightlevelsduetoanextensionoftheplant’scanopyupwardthroughthewatercolumn(RodriguesandThomaz2010).ThebuoyancyofE.crassipesallowsittoshadeoutanyphotosyntheticorganismgrowingwithinthewatercolumnandthus,potentiallyaffectsitsabilitytocompetewithotherspeciesunderamodifiedlightregime.Withregardtosubmersedmacrophytes,aspeciesthatcaneffectivelyoutgrowitscompetitorunderambientlightconditionsintheDeltahastheabilitytoshadeoutitscompetitorsand/orutilizemoreoftheavailableresourcestothedetrimentofcompetingspecies.

3.2 WATER CLARITY

TheDeltahashistoricallybeenviewedbyresearchersaslightlimitedduetohighturbidity,andthisconditionhasbeenusedtoexplain,inpart,theoveralllowproductivityoftheestuaryinthepresenceofnutrientconcentrationsthoughtsufficienttocauseeutrophication(ColeandCloern1984,1987).Lightlimitationislikelytobemostsevereinturbidwatersoftheestuarywhichareaffectedbywind‐andtide‐drivenverticalmixingandre‐suspensionofinorganicsediment,andisparticularlyhighinshallowareasandareassubjecttostrongwinds(Kimmereretal.2012).Inlocalizedareaswherelightlimitationisn’tlimitingprimaryproductivity,secondaryfactors,suchasnutrientavailability,temperature,salinity,andphotoperiod,cansupportalgalblooms(ColeandCloern1984).Deltawatershaveshowedincreasedclarityoverthepast50years.WrightandSchoellhamer(2004)foundthatsuspendedsedimentsfromtheSacramentoRivertotheDeltahavedecreasedbyabouthalfduringtheperiod1957to2001,whileJassby(2008)showeda2to6%decreaseperyearinsuspendedparticulatematterbetween1975and2005.

Asdiscussedabove,increasedirradiancecanimpartacompetitiveadvantagetothosespeciesthathaveprotectivepigmentstolimitoravoidphoto‐inhibitionunderconditionsofhighirradiance,thosespecieswithhighphotosyntheticratesunderhighirradiance,andthosespeciesthatexhibitlowphotosyntheticefficiencyatlowlightlevels.Anincreaseinwaterclaritywouldresultinanincreaseinirradianceinthewatercolumn,whichwouldbenefitthosespecies–particularly,cyanobacteria,suchasMicrocystisandC.raciborskii–thatgrowwellunderhighlightconditions.ResearchershaveobservedanincreaseintheabundanceofStuckeniapectinata(sagopondweed),anativesubmersedmacrophyte,intheDeltaoverthelast20yearsandhavepositedincreasedwaterclarityandthusgreaterlightavailabilitymaybepartiallyresponsibleforitsexpansion(WrightandSchoellhamer2004;Schoellhamer2011;Hestiretal.2013).

3.3 TEMPERATURE

Increasesintemperature,uptosomecriticalthreshold,areexpectedtoincreasetheestablishmentandgrowthratesofphytoplanktonandfloatingandsubmersedmacrophytes.Temperatureisconsideredakeyfactorthatcontrolsthegrowthrateofcyanobacteria(RobartsandZohary1987,Butterwicketal.2005,Watkinsonetal.2005,Reynolds2006,PaerlandHuisman2009).Cyanobacteriaisolatedfromtemperatelatitudes(i.e.,excludingpolarregions)exhibitgrowthoptimaattemperaturesbetween25and35°C(Reynolds2006,Lurlingetal.2013).SpeciesresponsibleforcyanoHABsshowgrowthoptimawithinthisrange,withAnabaenaspp.observedtohaveoptimumgrowthat25°C,C.raciborskiiandPlanktothrixagardhiiat27.5°C,andtwoMicrocystisaeruginosastrainsat30‐32.5°C(Lurlingetal.2013).Cyanobacteriatypicallyshowlowergrowthratesatcoldertemperaturesandhighergrowthratesatwarmertemperaturesascomparedtootherphytoplanktontaxa,suchasdiatomsanddinoflagellates(Boydetal.2013,Butterwicketal.2005,Kudoetal.2000,Lurlingetal.2013,YamamotoandNakahara2005).Asevidenceofthis,decreasesintemperaturethatoccurinthefallandwinterareobservedtocoincidewithnon‐activegrowthphasesinphytoplankton.Differencesintemperaturegrowthoptimaamongvariousphytoplanktontaxaarehypothesizedtohaveimportanceininfluencingphytoplanktoncommunitycompositionasglobalclimatechangeproducestemperaturesabove20°Cwithmoreregularity(Lehmanetal.2005,PaerlandHuisman2008).

T&Oeventshavealsobeenfoundtobecorrelatedwithtemperatureinsomesystems.Regressionapproachesusingasuiteofenvironmentalvariableshaveshownairand/orwatertemperaturetobeastrongcorrelatewithT&Ocompoundconcentrationsinatleastfourreservoirs(Tungetal.2008;Uwinsetal.2007;Yenetal.2007).

Withrespecttomacrophytes,increasedgrowthtendstocauseareductioninflowsurroundingastand,whichcausesincreasesinlocaltemperaturesthatfurtherenhancegrowthuptosomelimitingtemperature.LaboratorygrowthstudiesofE.densashowedincreasesinbiomassatawatertemperatureof22°C,reducedbiomassproductionat26°C,andgreatreductionsinbiomassat30°C(BorgnisandBoyer,inpress).Similartophytoplankton,decreasesintemperaturethatoccurinthefallandwinterareobservedtocoincidewithsenescenceanddiebackinmacrophytes.DiebackofE.crassipeshasbeenobservedintheDeltaduringperiodsoffrostandfreezingtemperatures(Foe,pers.comm.;Khanna,pers.comm.;ascitedinBoyerandSutula2015).

3.4 RESIDENCE TIME/FLOW

Residencetimeisameasureofhowlonganobject(e.g.,fish,plant,pollutant,parcelofwater)remainsinadefinedregion.Itisagoodmeasureofthelengthoftimeanobjectstaysintheestuary.Deltaresidencetimeisaffectedbyinflows,seasonalchangesinhydrology,diversions/exports,tides,physicalstructuresofwaterchannels(i.e.,deadendsloughvs.riverchannel),andtheoperationofstructuressuchasgatesandbarriers.Flowvelocitycertainlyhasalargeimpactonresidencetimesashigherflowsproduceshorterresidencetimesandlowerflowspromotelongerresidencetimes.Along‐termtrendsanalysis(1990–2004)ofDeltaresidencetimeperformedbyDWR’sDeltaModelingSection5foundnosignificantdifferencesinresidencetimeindexesfortheSacramentoandSanJoaquinriversovertheperiodanalyzed.However,thestudydidfindthefollowing:SacramentoRiverresidencetimewashigherduringthedrierwateryearsoftheearly1990s;SanJoaquinRiverresidencetimewashigherinlatefall/earlywinterintheearly1990s;latesummerandearlyfallperiodsshowedthehighestresidencetimes;laterwinterexhibitedthelowestresidencetimes;andspringfeaturedthegreatestvariabilityinresidencetimes.

Longerresidencetimesgenerallypromotegreaterexposuresoforganismstotheirphysicalandbiogeochemicalenvironments.Lowerflowsandlongerresidencetimehelptoestablishmacrophytebedsthatcaneventuallylowerflowsandalterlocalhabitatsthemselves,whichpromotetheirowncontinuedgrowth(BoyerandSutula2015).Lowerflows,altereddepositionofsuspendedsediments,andincreasedtemperaturescanleadtoalteredhabitatsthatpromotethegrowthofsomeorganisms(e.g.,macrophytes,phytoplankton,fish,zooplankton,etc.)overothers.Cyanobacterialabundance,cellsize,andtoxinconcentrationarealsopositivelycorrelatedtoincreasedresidencetime(Elliott2010,Romoetal.2013).

5Posteravailableat:http://baydeltaoffice.water.ca.gov/modeling/deltamodeling/presentations/DeltaResidenceTimeResults_mmierzwa.pdf

3.5 SALINITY

AmbientsalinityintheDeltaistypicallymanagedtoprovidefreshwaterformunicipal,industrial,andagriculturalbeneficialuses(Moyle et al. 2010).DiminishedfreshwaterflowsintotheDeltaduringtherecentdrought(2011–2015)haveresultedinincreasedsalinities(upto5pptormore)reachingasfareastasShermanIsland(BoyerandSutula2015).SealevelriseandchangesinthetimingandmagnitudeofsnowmeltduetoglobalclimatechangearehypothesizedtoincreaseDeltasalinityby1to3pptby2090(Knowles and Cayan 2002).SalinitymeasurementstakeninthewesternDeltabytheC&HSugarRefiningCompanysincetheearly1900shaverevealedthatsalinityintrusioninSuisunBaynowoccursfourmonthsearliereachyearthanhistorically;MarchascomparedtoJuly(Contra Costa Water District 2010).

Freshwatercyanobacteriacapableofformingtoxinsshowarangeoftolerancesforsalinity.TheleasttolerantisCylindrospermopsis,whichshowsdecreasedgrowthabove2.5ppt.AnabaenopsisandNodulariaspp.canthriveatsalinitiesfrom5‐20ppt(Moisanderetal.2002).Microcystisaeruginosacantoleratesalinitiesupto10pptwithoutachangeingrowthrateascomparedtothatobservedwhenthealgaisgrowninfreshwater(Tonketal.2007).ThewhitepaperproducedbytheCyanobacteriaWorkgroupconcludedthatsalinitymaynotbeastrongbarrierthatrestrictstheoccurrenceofcyanoHABsintheDelta(Berg,andSutula2015).

AstudythatinvestigatedthesalinitytoleranceofE.densafoundthegrowthofthemacrophytetobestronglylimitedbyincreasesinsalinity,withlossofbiomassatasalinityof5pptandmortalityanddecompositionatsalinitiesof10and15ppt(BorgnisandBoyer,inpress).ThenativepondweedS.pectinataisexpectedtohavethegreatestsalinitytoleranceamongallmacrophytesintheDeltabasedongreenhousegrowthexperimentsthatshowedbiomassaccumulationwithincreasedsalinitiesupto15pptascomparedtocontrols(BorgnisandBoyer,inpress).E.crassipeshasbeenshowntoundergostressatsalinitiesaslowas2.5ppt(Haller et al. 1974)andexperiencemortalityatsalinitiesabove6–8ppt(Muramotoetal.1991;OlivaresandColonnello2000).

3.6 NUTRIENT CONCENTRATIONS AND RATIOS

TheSanFranciscoEstuary(SFE),whichincludestheSacramento‐SanJoaquinDelta,SuisunBay,SanPablo,CentralandSouthBays,isanexampleofanaquaticecosystempossessingnitrogenandphosphorusconcentrationssufficienttoproduceeutrophication,yet,overall,itfeatureslowphytoplanktonproduction(Cloern2001;Jassbyetal.2002).ItsannualloadingratesofbothtotalNandtotalParegreaterthanthosemeasuredinChesapeakeBay,buttheSanFranciscoEstuaryhistoricallyexhibitednoneofthephytoplanktonbloomscharacteristicoftheChesapeake(Cloern2001).IntheSFE,itiswellestablishedthatfactorssuchasturbidity(actingtolimitlightpenetrationinthewatercolumn),freshwaterflow,residencetime,andbenthicgrazingbybivalvesalldecreasethesensitivityofthesystemtonutrientloading(Cloern2001).Jassbyetal.(2002)showedthatincreasesordecreasesinnutrientlevelsintheDeltahavelittleeffectontheecosystem’sprimaryproductivityduetothephysicalfactorsthatexertastrongerinfluenceonphytoplanktonproductionthanambientnutrientconcentrations.Inrecentyears,someresearchershavehypothesizedthattheformsofN(ammoniumversusnitrate)availableforuptakeinthesystem(Wilkersonetal.2006)andtheratioofNtoPinthesystem(Glibert2010)areactingto

controltheprimaryproductivityoftheSFEtoagreaterdegreethanoncethought.ThosehypothesesareaddressedintheNutrientFormsandRatioswhitepaperproducedin2017aspartoftheDeltaNutrientScienceandResearchProgram.

3.7 DISSOLVED INORGANIC CARBON

Theprocessofphotosynthesisallowsplantsandotherorganismstoconvertlightenergyintochemicalenergythroughuptakeandconversionofinorganiccarbondioxideandwatertoorganiccarboncompounds(sugars)andoxygen.Floatingmacrophytescanaccessadequatecarbondioxidefromtheatmosphere,butphytoplanktonandsubmersedmacrophytesmustobtaintheircarbonsourcefromthewatercolumnintheformofdissolvedinorganiccarbon(DIC).AsphotosynthesisbyaquaticplantsandalgaepreferentiallyremovesCO2fromthewatercolumn,carbonicacid(H2CO3)becomesmoreprevalentandpHconcentrationsincrease.Thisleadstobicarbonate(HCO3‐)becomingamoreprominentformofDICinthewatercolumn(Sand‐Jensen1989;Santamaría2002).WhenphotosynthesisremovesCO2fromthewatercolumnataratefasterthanatmosphericCO2andrespirationcontributeCO2tothewatercolumn,ahigherpHconditionisformedwherebicarbonatebecomestheprimaryformofDICavailabletophotosyntheticorganisms.Macrophytesthatcanutilizebicarbonateefficiently,suchasE.densaandCeratophyllumdemersum(coontail;asubmersed,nativeperennial)(Cavallietal.2012),mayhaveacompetitiveadvantageoverthosespeciesthatdonotgrowaswellwithbicarbonateasaDICsource.Inadditiontopotentialcompetitiveadvantageforsomeorganisms,theconversionofDICtodissolvedorganiccarbon(DOC)viaphotosynthesismayresultindrinkingwaterqualityproblemsduetotheformationofcarcinogenicbyproductsfromthedisinfectionprocessasdiscussedearlierinSection2.0.

4.0 Management of Identified Issues

4.1 MANAGEMENT OPTIONS

ThissectiondiscussespossiblemanagementoptionstoaddressseveraloftheimportantissuesdiscussedintheprevioussectionsregardingimpactstoDrinkingWatersourcedfromtheDelta.

4.1.1 Nutrient Load Management

Taste and Odors

NutrientcontrolmeasureshaveproventobeineffectiveasmanagementtoolstocontrolT&OeventsorthedistributionandabundanceofT&O‐causingmicrobesinthefewsystemswhichhavestudiedtheissue,althoughitisunclearwhethertheresultsfromothersystemsareapplicabletotheDeltaandwatersupplysystemsthattransportandstoreDeltawater.OutbreaksofChrysophytes(taxonomicgroupcontainingdiatoms,yellow‐green,andgolden‐brownalgae),andtheirpolyunsaturatedfattyacid(PUFA)derivatives,showlittleapparentrelationshiptonutrientsonabroadscaleacross91northtemperatelakesinCanada(Watsonetal.1997;Watsonetal.2001a).Furthermore,incertaincasesremedialnutrientreductionmayactuallyincreaseepisodesofChrysophyteblooms(e.g.,Juttneretal.1986;Yanoetal.1988;Nicholls1995).WhereT&Oepisodeshavebeenlinkedtoplanktoniccyanobacteria,theeventsarenotwell‐explainedbythenutrientstatusorplanktonicproductivityofthesystems(e.g.,Watsonetal.2008).

Insomecases,remedialactionplansforT&Oproblemswerefoundtobeunsuccessfulbecausetheyattemptcontrolofnoxiousmetabolitesthrougharelianceonwatertreatmentandbroad‐scalenutrient–biomassmodels.Nutrientcontrolapproachesareunderminedbyseveralfactors,includingthefactthat(1)differentT&O‐compoundproducingtaxashowdisparatepatternsacrossnutrientandmixingregimes,(2)epibenthicandperiphyticmicrobesarewidespreadculpritsintheproductionofT&Ocompounds–andgrowthofattachedmicrobesismoreweaklylinkedtoconditionsinthewatercolumnthanphytoplankton,(3)deep‐layercyanobacteriamaxima,suppliedbyinternallyrecyclednutrientsinthehypolimnionofastratifiedsystem,canbeasourceofT&Ocompounds,(4)nutrientreductionstrategieshaveincreasedwatertransparencyandlittoralproductioninmanysystems,improvingconditionsforattachedalgae,and(5)othergroupsofMIBandgeosmin‐producingorganismsarenotalgae,butactinomycetebacteria,myxobacteria,fungi,andothers.Proactivemanagementoftasteandodorissuesneedstoconsiderthesourcesoftheproblembyidentifyingtheenvironmentalandbiologicalagentsandtheirpotentialcontrols,includingecologicallysoundwatershedandsourcewaterremediationandmanagement(Juttner&Watson2007).

Althoughsurfacebloomsareperceivedasprimarysourcesofwaterodor,twiceasmanyknownodor‐causingcyanobacterialspeciesareepibenthic,notplanktonic(Jutter&Watson2007).Inaddition,twocyanobacteriagenera(HyellaandMicrocoleus),whichformbiofilmsonaquaticmacrophytes,havebeenassociatedwithT&Oevents.AttachedcyanobacteriahavebeenimplicatedassourcesofMIBorgeosmininmanystudiesoflakes,reservoirs,orrivers(Burlingameetal.1986;

Sugiuraetal.1998;Watson&Ridal2004;Bakeretal.2006).Consequently,decreasesinphytoplanktonicbiomass(suchasmightbetheaimofnutrientreductionstrategies)couldhavetheunintendedconsequenceofincreasingtheavailablesubstrateforthemainculpritsofT&Oepisodesinthesereservoirs.

Cyanobacteria

TheCyanobacteriaWorkgroupconcludedthattheinitiationofMicrocystisbloomsareprobablynotassociatedwithchangesinnutrientconcentrations,theformsofthenutrients(e.g.,ammonium)ortheratiosofNtoPintheDelta(BergandSutula2015).Therefore,itisunlikelythatnutrientcontrolwillhaveaneffectonlimitingbloominitiationsofcyanoHABs,suchasMicrocystis.However,theWorkgroupconcludedthatnutrientreductionmightlimitbloomduration,intensity,andpossiblygeographicextent.Inordertoachievethesechangesnutrientswouldlikelyneedtobemanagedtobringtheirconcentrationsdowntoalevelthatwaslimitingtocyanobacteriagrowth.

Macrophytes

TheMacrophyteWorkgroupdeterminedthat,duetotheinconclusiveconnectionbetweennutrientconcentrationsandmacrophyteprevalenceintheDelta,theeffectthatnutrientmanagementwillhaveoncontrollinginvasivefloatingandsubmersedmacrophytesisuncertain.OthermanagementoptionsidentifiedbytheWorkgroupincludedmechanical,chemical,biologicalcontrol,andintegratedcontrolmethods,aswellasbarrierstoprotectsensitiveareas.Thegrouprecommendedadditionalstudiestodeterminethebestcontrolmechanism(Boyer&Sutula2015).

4.1.2 Harvesting (macrophytes)

TheMacrophyteWorkgroupfoundthatmechanicalremovalispracticedincertainareasoftheDelta,butmaynotalwaysbeeffectiveandcanexacerbatetheproblemiffragmentsofplantsarecreatedwhichserveaspropaguleswhichcanseednewpopulationsindistantlocationsoftheDelta.MechanicalremovalofE.Densahasoccurredbutcauseddistantpopulationstoestablishduetopropaguleformation(Anderson2003;Spenceretal.2006).MechanicalgatheringofE.Crassipeshasbeeneffectiveinlimitedareas;however,theremainingshreddedpiecesoftheplantseitherneedtoberemovedwhichincursasignificantcostor,ifleftinplace,willdecomposethusre‐mineralizingnutrients,loweringdissolvedoxygen,andpotentiallyseedingfuturepopulationsthroughpropagulegeneration(Greenfieldetal.2007).

AUnitedStatesDepartmentofAgricultureAgriculturalResearchService(USDA‐ARS)programinvestigatedintegratedcontrolmethodsforbothE.densaandE.crassipesanddevelopedamappingapplicationtotrackdevelopmentofproblempopulationsinordertoprioritizeharvestingtreatmentlocations.ThetoolisusedtotargetnurserypopulationsintheDeltathatserveassourcesforearlyseasoninfestations(Brendaetal.2015).MechanicalharvestingisalsousedinCliftonCourtForebayandO’NeillForebay,andsomesectionsoftheaqueductarescrapedbydraggingalargechainalongtheaqueductlining.

4.1.3 Biological Control (macrophytes)

Biologicalcontrolmechanismscanincludeintroducingcompetitorsorgrazerstohelpcontrolthepopulationofinvasivemacrophytes.CertainspecieswereintroducedtotheDeltaintheearly1980sinanattempttocontrolE.crassipes,includingtheweevil,Neochetinabruchi,whichbecameestablished,butdidnotresultinanyeffectivereductionoftheE.crassipespopulation(Stewartetal.1988).TheMacrophyteWorkgroupalsodetailedtheongoingintroductionoftheplanthopper,Megamelusscutellaris,forE.crassipescontrolwhichisbeingmanagedbytheUSDA‐ARSandtheCaliforniaDepartmentofFoodandAgriculture(CDFA)(BoyerandSutula2015).ThisorganismhasbeenshowntobeeffectiveinreducingtheE.crassipespopulationinFlorida.

4.1.4 Chemical Additions (e.g. copper sulfate, etc. for nuisance algal blooms, taste and odor episodes)

TheprimarymechanismforcontrollingalgalgrowthintheDeltaandvariouslocationsintheSWPisbyapplicationofcoppersulfateorothercopperproducts.IntheSBA,coppersulfatehasbeenappliedeverytwotofourweeksfromMarchuntilOctoberorNovembersince2011,dependinguponwatertemperaturesandalgalconditions.Thechemicalapplicationiseffectiveinreducingtotalalgalbiomasstopreventfilterclogging;however,evenwiththeapplicationbiomassreachesconcentrationshighenoughtoaffectfilteringeverysummer(SeeSection2.2.1).Copperproductshavenotbeenusedsince2006inCliftonCourtduetopotentialimpactsonthreatenedandendangeredspecies.

Therearepotentialunintendednegativeconsequenceswithusingcoppersulfateandotherchemicaladditivestotreatalgalblooms.OnestudyinaMinnesotaLakefoundshort‐termeffectsofdissolvedoxygendepletion,rapidnutrientrecycling,andreleasefollowingdeathofabloom,aswellasoccasionalfishkillsfromoxygendepletionsandcoppertoxicity.Long‐termeffectsofnearly60yearsoftreatmentincludedcopperaccumulationinsediments,growthofcopper‐tolerantalgalspecies,algalandfishpopulationshifts,lossofmacrophytes,andreductionsinbenthicmacroinvertebrates(Hanson&Stefan,1984).

5.0 Data Gaps

Thissectionsummarizestheknowledgegapsidentifiedforthefollowingtopics:

NuisanceAlgalBloomso Cyanobacteria

Macrophytes

LiteraturereviewsanddatagapanalyseshavebeenperformedtodatebytheCyanobacteriaandMacrophyteWorkgroups.Theresultsfromthatworkhaverelevancetotheconcernsofdrinkingwaterpurveyorsregardingtheimpactsofcyanobacteriaandmacrophytesontheirconveyancefacilitiesanddrinkingwatertreatmentplants.TheliteraturereviewsperformedbytheCyanobacteriaandMacrophyteWorkgroupsfoundalackofinformationspecifictotheDelta,aswellaswhatecologicalfactorsintheDeltamaybepromotingprimaryproductivity.Tothisend,eachworkgroupwasonlyabletoanswerfullythefirstquestionposedtothem:

Provideabasicreviewofbiologicalandecologicalfactorsthatinfluencetheprevalenceofcyanobacteriaandtheproductionofcyanotoxins(CyanobacteriaWorkgroup).

Howdoessubmersedandfloatingaquaticvegetationsupportoradverselyaffecttheecosystemservicesandrelatedbeneficialuses?(MacrophyteWorkgroup).

RecommendationsforthetypesofresearchandmodelingthatareneededtobridgeexistingdatagapsareprovidedinSection6.0.

5.1 PREVALENCE OF PROBLEMS IN THE DELTA AND DOWNSTREAM CONVEYANCE AND STORAGE FACILITIES

TheprevalenceofcyanoHABsintheDeltaisnotwelldocumented,andpromptedtheCyanobacteriaWorkgrouptorecommendexpandedsurveillancemonitoringtocollectacomprehensivesetofmeasurementsthatwillassistafullevaluationoftherisktohumanhealthandaquaticlifeduetocyanotoxins,aswellastobetterunderstandthelinkagesofvariousfactorsordrivers(nutrients;temperature;highirradiance;flowasitrelatestowaterclarity,residencetime,andwatercolumnstratification;benthicgrazing;andsalinity)inpromotingandmaintainingcyanoHABs.

Similarly,theMacrophyteWorkgroupfoundthatknowledgeregardingmacrophytegrowthandbiomasstrendsintheDeltaislacking,andrecommendedexpandedsurveillancemonitoringthroughremotely‐sensedarealcoverageandfield‐basedmeasurestoestimatebiomassovertime.Monitoringwasalsorecommendedtoevaluatemacrophytespeciescommunitycompositionovertime.Similartothedataneedsofthosestudyingcyanobacteria,thereisalsoaneedtocollectinformationregardingtheeffectsoflight,temperature,salinity,flow,substratestability,chemical/mechanicalcontrol,andinterspeciescompetition.

WithrespecttocyanoHABsinStateandFederalconveyanceandstoragefacilities,asdiscussedinSection2.0,monitoringprogramsimplementedbyDWRandothershavedetectedmicrocystinin

BarkerSloughattheNorthBayAqueductintake,CliftonCourtForebay,BanksPumpingPlant,DyerReservoirontheSBA,theGianelliandPachecointakesinSanLuisReservoir,theO’NeillForebayOutlet(Check13)ontheCaliforniaAqueduct;andinPyramidLake,CastaicLake,LakePerris,andSilverwoodLakeinSouthernCalifornia.TheextentofmonitoringperformedbydrinkingwaterpurveyorsforcyanoHABsandvariousfactorssuspectedofpromotingbloomsintheirfacilitiesisunknown,butexpandedmonitoringintheDeltaandinconveyanceandstoragefacilitieswouldcertainlyhelptoexpandtheknowledgebasetodeterminewhatmanagementactionsmaybemosthelpfulincontrollingcyanoHABsandmacrophytes.

5.2 SPATIAL AND SEASONAL OCCURRENCE OF PROBLEMS

SimilartothelackofknowledgeregardingprevalenceofcyanoHABandmacrophyteproblems,bothworkgroupsrecommendedexpandedsurveillancemonitoringasameanstobettercharacterizethespatialandseasonaloccurrencesoftheseproblems.Ingeneral,cyanoHABsarewarmseason(summerandearlyfall)phenomena,bothintheDeltaanddrinkingwaterfacilities.DuetothelackofcomprehensivemonitoringdataintheDelta,acompleteunderstandingofthespatialoccurrenceofcyanoHABshasyettobedeveloped.

ProblemscausedbyE.crassipesandE.densagrowtharemostcommoninspringthroughfallwhenthesemacrophytesgrowmostrapidly.Bothofthesenon‐nativemacrophytesoccurthroughouttheDelta,withtheircontrolbytheCaliforniaDepartmentofBoatingandWaterwayslinkedtotheirimpairmentofnavigablewaters.

Again,thespatialandseasonaloccurrenceofcyanoHABsandmacrophytesindrinkingwaterfacilitiesisunknown,butexpandedmonitoringintheDeltaandinconveyanceandstoragefacilitieswouldcertainlyhelptoenhancetheknowledgebasethatallstakeholderswillrelyupontodeterminewhatmanagementactionsmaybemosthelpfulincontrollingcyanoHABandmacrophytegrowth.

5.3 EFFECTIVENESS OF ALTERNATIVE MANAGEMENT OPTIONS ON SPECIFIC PROBLEMS

Historically,controlofmacrophytesintheDeltaanddrinkingwaterfacilitieshasbeenaccomplishedthroughapplicationofchemicals(primarily,coppersulfate)andmechanicalharvesting.Controlofalgaeindrinkingwaterfacilitieshasalsobeenconductedthroughtheapplicationofcoppersulfate.Alternativemanagementoptionsforthecontrolofspecificproblemshavenotbeenattemptedtoanygreatdegree,ifatall.Thecontrolcapabilitiesofvariousdriversaspotentialmanagementoptionshaveyettobeevaluated.TheresearchandmodelingrecommendationsinthefollowingsectionareintendedtodevelopinformationregardingthefactorsnecessarytoidentifypotentialmanagementactionsthatcanbetakentolimitcyanoHABsandthespreadandgrowthofmacrophytes.ItremainstobeseenwhethersomeorallmanagementactionsthatcouldacttolimitcyanoHABsandthespreadandgrowthofmacrophytesintheDeltacouldbeusedindrinkingwaterfacilities.

5.4 MONITORING DATA AND PROCESS COEFFICIENTS/PARAMETERS REQUIRED FOR ECOSYSTEM AND MANAGEMENT MODELS

TheliteraturereviewsconductedbytheCyanobacteriaandMacrophyteWorkgroupsidentifiedmultipleareaswhereambientmonitoringdataandprocesscoefficients/parametersarelackingfortheDelta,andwillneedtobedevelopedthroughfuturemonitoringandresearcheffortstobestinformtheecosystemmodel(s)recommendedfordevelopment.Inadditiontoasuiteofenvironmentalparameterspinpointedformonitoring,cyanobacteriaandmacrophytegrowthrates,macrophyteturnoverrates,nutrientuptake,transformationandfluxrates,watercolumnmixingrates,andflushingrates(causingwashout)wereidentifiedasbeingnecessarytosupportecosystemmodeldevelopment(BergandSutula2015;BoyerandSutula2015).

6.0 Recommendations for Monitoring, Research and Modeling Priorities

6.1 PROBLEM DEFINITION

Multipleknowledgegapsexistinourunderstandingoftheimportanceofnutrientprocessesanddriversthoughttoimpactcyanobacteria,cyanotoxins,tasteandodorproblems,macrophytes,andotherproblemsimpactingdrinkingwaterusesintheDeltaandinareasservedbyDeltawatersupplies.Inordertodeveloptheknowledgenecessarytobridgethegapsinourunderstandingoftheseproblems,additionalmonitoring,researchandmodelingisneeded,bothintheDeltaandindownstreamconveyanceandstoragefacilities.Futureresearchneedstobetargetedtoanswerquestionsrelatedtotheimportanceofnutrientsincombinationwithotherhydrologic,physical,biological,andchemicalfactorsinthecontroloftheidentifiedproblems.Thedevelopmentofnewinformationwillprovideamorecompleteunderstandingofthemostappropriatemanagementactions.

BoththeCyanobacteriaandMacrophyteWorkgroupsproposedanumberofmajorsciencerecommendationsgiventhedatagapsthatwereidentified.BothworkgroupsidentifiedtheneedforadditionalmonitoringintheDelta(BergandSutula2015;BoyerandSutula2015).TheCyanobacteriaWorkgrouprecommendedthedevelopmentofanecosystemmodelofprimaryproductivitytofurtherinformhypothesesonfactorscontrollingprimaryproductivityandthefutureriskofcyanoHABs(BergandSutula2015).TheMacrophyteWorkgrouprecommendedthedevelopmentofabiogeochemicalmodeloftheDeltafocusedonnutrientandorganiccarbonfateandtransport.TheMacrophyteWorkgroupalsorecommendedareviewofcurrentandpotentialfuturecontrolstrategiesforinvasivemacrophytesintheDeltathatincludesconsiderationofbarrierstoreducethemovementofvegetationintosensitiveareasorthosewithheavyhumanuse(BoyerandSutula2015).Thesemajorsciencerecommendationsshouldbesupportiveofdevelopinginitialinformationusefultoaddressingdrinkingwaterconcernsforcyanobacteriaandmacrophytes.

6.2 ROLE OF NUTRIENTS IN COMBINATION WITH OTHER FACTORS

Cyanobacteria – Cyanotoxins

MuchremainsunknownwithregardtotherolenutrientsplayininfluencingthemagnitudeandfrequencyofcyanobacteriabloomsintheDeltaanddownstreamconveyanceandstoragefacilities.AshiftinDeltaphytoplanktoncommunitycompositioninrecentyearstoincludealargerpercentageofcyanobacteria,bothtoxin‐producingandnon‐toxin‐producingstrains,currentlyaffectsdrinkingwaterduetotasteandodorproblemsandthepresenceofcyanotoxins.WecurrentlylackinformationaboutwhetheranattainablereductioninnutrientconcentrationsintheDeltacouldreducecyanobacteriabloomsandassociatedcyanotoxinproductionwithintheDeltaanddownstream.GapsinourunderstandingoftherolenutrientsplayregardingcyanobacteriabloomsintheDeltaanddownstreamfacilitiesareassociatedwithourlackofunderstandingofthe

rolesofotherdrivers,including:temperature;irradiance;flowasitrelatestowaterclarity,residencetime,andwatercolumnstratification;benthicgrazing;andsalinity.

Expandedsystem‐widesurveillancemonitoringintheDeltaanddownstreamconveyanceandstoragefacilitiesisrecommendedtodevelopgreaterspatialandtemporalknowledgeinthefollowingareas:

Identificationoflocations,extent,timinganddurationwherecyanobacteriabloomsoccurintheDeltaandindownstreamconveyanceandstoragefacilities.DeterminationoftheriskthatcyanotoxinconcentrationsintheDeltaandinsouthofDeltareservoirsandconveyancestructuresposetodrinkingwaterduetophysicalproximity.

Measurementofenvironmentalfactors(e.g.,nutrients,temperature,irradiance,turbidity,flow,andsalinity)thatco‐occurwithdifferentstagesofbloomdevelopmenttogainanunderstandingofthepresenceandmagnitudeofthedriversthatinfluencebloominitiation,bloommagnitude,andcyanotoxinproduction.Monitoringshouldincludeinstantaneous,annual,andinter‐annualmeasurements.

Fieldandlaboratorystudiesarealsorecommendedtoprovideinsighttowhetherthedriversthatinfluencecyanobacteriabloomscanbemanaged,andwhateffectthecontrolofthesefactorshasoncyanobacteriabloommagnitudeandduration.Studiesarerecommendedinthefollowingareas:

Initiationoflaboratoryandfieldstudiesduringbloomstodeterminewhethermodificationofnutrientconcentrationscanreducethemagnitudeandfrequencyofcyanobacteriablooms(andassociatedtoxinlevels)intheDeltaanddownstreamfacilities.

Investigationoftheeffectsthatotherkeyfactors(e.g.,temperature,turbidity,mixingrates,andflow(causingwash‐out))haveonbloomformationandattenuation.

Cyanobacteria – Taste and Odors

Theroleofnutrientconcentrationsininfluencingtheoccurrence,magnitude,anddurationoftasteandodorepisodesintheDeltaandindownstreamconveyancefacilitiesandreservoirsisnotwellunderstood.Wecurrentlylackinformationabouttheformsandconcentrationsofnutrientsthatinfluencethegrowthofthespeciesofbenthicandplanktoniccyanobacteriathatcausetasteandodorproblems.Finally,gapsexistinourunderstandingoftherolesofotherfactorsontheoccurrenceanddurationoftheseepisodes,includingtemperature;lightlevels;waterclarity;waterresidencetime;waterstratification;andotherfactorsthatinfluencealgalcommunitycompositionandtheproductionofcompoundsresponsiblefortasteandodorproblems.

Expandedsurveillancemonitoring,modeling,andanalysisofavailabledataintheDeltaandindownstreamconveyanceandstoragefacilitiesisrecommended,asfollows:

Performanceofmicrobialsurveysand/orspeciesstudiestoexpandourknowledgeoftheprevalenceofproblematicbenthicandplanktoniccyanobacteriaspecies,thedriversthatpromotetheirgrowth,andwhattheirpotentialcontributiontotasteandodorepisodes

mightbe.Assessimpactsofbenthicspeciesascomparedtothebetterstudiedplanktoniccyanobacteriaspecies.

SynthesizeavailabledatatoidentifyspatialandtemporaloccurrenceoftasteandodorproblemsinthewatersupplyconveyancefacilitiesdownstreamoftheDelta.Determineifmodificationstomonitoring,suchasfocusedmonitoringduringblooms,wouldenhancethequalityofthedataandunderstandingofbloomdistributionsinthesefacilities.

PerformmonitoringandmodelingtounderstandthemagnitudeandimportanceofsourcesofnitrogenandphosphorusintheDelta,withconsiderationforDeltahydrodynamics,variableDeltaflowconditions,nutrienttransformations,tributaryinputs,sedimentflux,etc.aspartofanassessmentoftheroleofnutrientsintasteandodorproblemoccurrenceandcontrol.ThiseffortshouldincludeanalysisoftheDWRMWQIenhancedmonitoringforNandPdatathatwascollectedtoprovideinputstotheDSM2waterqualitymodelandanalysisofhistoricalMWQImonitoringofDeltaIslanddischarges.

FieldandlaboratorystudiesarealsorecommendedtoprovideinsightintothepossiblemanagementoftasteandodorproblemsintheDeltaandindownstreamfacilities.Studiesarerecommendedinthefollowingareas:

Measurementofenvironmentalfactors(e.g.,nutrients,temperature,irradiance,turbidity,flow,andsalinity)thatco‐occurwithdifferentstagesoftasteandodor‐producingcyanobacteriabloomdevelopmentindownstreamwatersupplyfacilities.Investigationoftheeffectsthatturbidity,mixingrates,andflow(causingwash‐out)haveontasteandodorepisodeinitiationandattenuation.

Insitustudiesinreservoirsandconveyancefacilitiestoisolatetheincrementalimpactofchangesinnutrientwatercolumnconcentrationsonproliferationofplanktonicandbenthiccyanobacteriaspeciesresponsiblefortasteandodorepisodes.DeterminationoftheeffectthatambientnutrientconcentrationreductionswillhaveontasteandodoroccurrencesdownstreamofDeltainreservoirsandconveyancestructures.Theuseof“Limnocorrals6”wassuggestedasoneidea.Notethatalimitationintheuseof“limnocorrals”isthattheyreduceturbulenceandquicklychangethelightclimate.

Macrophytes

SimilaritiesexistbetweencyanobacteriaandmacrophytebloomswithregardtoourlackofknowledgeabouttheextentofthemacrophyteproblemintheDeltaanddownstreamconveyanceandstoragefacilities.Questionsalsoexistregardingthedegradationofwaterqualityandimpactstobeneficialuses,driversthataremostinfluentialinpromotingthegrowthofinvasiveandnative

6Alimnocorral(orlimnocorral,limno‐corral)isanenclosurethatextendsfromthewatersurfacetothesediment,whereitisanchored,thatallowsadefinedvolumeofwatertobephysicallyseparatedfromthesurroundingwaterbody.

macrophytes,andwhichofthesedriverscanbecontrolledthroughmanagementactions.Aswithcyanobacteria,therolethatnutrients(viaforms,concentrations,andtiming)playinstimulatingmacrophytegrowthintheDeltaanddownstream–especially,asitinfluencesthegrowthofinvasive,non‐nativespecies,suchasE.crassipesandE.densa–isnotcompletelyunderstood,noristheimpactthatotherfactors(light,temperature,salinity,flow,substratestability,chemical/mechanicalcontrol,andinterspeciescompetition)haveonthespreadandgrowthofmacrophytesintheDeltaanddownstreamconveyanceandstoragefacilities.Ofgreatestinteresttodrinkingwatermanagersistheabilitytocontrolthespreadandgrowthofmacrophytesinreservoirsandconveyancestructuresinareaswheresuchgrowthclogspumpsandfiltersandimpedesflows.ExpandingsurveillancemonitoringintheDeltaanddownstreamfacilitiesisrecommendedtodevelopgreaterknowledgeinthefollowingareas:

DeterminationoftheextentofinvasiveaquaticplantbloomsintheDeltaandindownstreamconveyanceandstoragefacilities,aswellasthedetectionofnewinvasionsthroughimplementationofacomprehensivemulti‐yearmonitoringprogram.

Measurementofenvironmentalfactorsandphysicalconditions(e.g.,nutrients,temperature,light,turbidity,flow,andsalinity)thatco‐occurwithnativeandnon‐nativemacrophytestogainanunderstandingofthepresenceandmagnitudeoffactorsthatco‐occurwithandinfluencemacrophytegrowthintheDeltaandindownstreamfacilities.Monitoringshouldincludeinstantaneous,annual,andinterannualmeasurements.

Fieldandlaboratorystudiesarealsorecommendedtoprovideinsightintothemanagementofdriversthatinfluencemacrophytegrowth,andtowhateffectthecontrolofthesefactorshasonmacrophytegrowth.Studiesarerecommendedinthefollowingareas:

DeterminationoffieldmethodsforrapidlyassessinginsitunutrientlimitationofmacrophytesintheDeltaandindownstreamfacilities.Conductlaboratoryculturestudiestoevaluategrowthrateasafunctionofambientnutrientconcentrationsinwaterandsediment.Analyzetissuenutrientconcentrationstodeterminetherelationshipbetweentissuegrowth,nutrientuptakerates,andnutrientconcentrations.Confirmrelationshipsinfieldtrials.

Ifnutrientreductionsareshowntosufficientlylimitmacrophytegrowthandsuchreductionscanbeachievedthroughthecontrolofpointsources,useofmesocosmstudiestodetermineifmechanicalandchemicalcontrolofmacrophytesisenhancedbynutrientreductions.

6.3 MODELING TOOLS AND SCENARIOS

Development of Modeling Tools

ThecomplexnatureoftheDeltaecosystemandtherangeofquestionsforwhichanswersaresoughtregardingthefactorsthatinfluencephytoplankton,cyanobacteria,andmacrophytegrowthrequiretheabilitytocharacterizemultipleprocessesintheformofamodelormodels.ThecollectionandanalysisofempiricaldataalonewillnotprovidetheabilitytotestfutureDelta

managementscenarios.TheModelingScienceWorkgroupidentifiedfourreasonswhymodelswillprovidevaluabletoolsformanagingwaterqualityintheDelta(Trowbridgeetal.,2015):

TheDeltaistoocomplextocomprehensivelyunderstandwithoutmodels.Empiricaldatacollectioncannotbeachievedatthespatialandtemporalscalesnecessarytofullycharacterizeandtestpotentialmanagementactions.

Modelscanprovideinsightintotheecologicalsignificanceofnutrientchangesfromanecosystemperspective.

Modelscanefficientlyallowstakeholderstodevelopandassessmanagementscenariostocharacterizetheeffectofnutrientsoverarangeofconditions.

Modelscanbeeffectiveforcommunicatingimportantinformationtostakeholders,regulators,andresourcemanagers,leadingtoacommonunderstandingofcomplexsystems.

FuturemodelingeffortsmustconsiderasuiteofimportantprocessesthatoperatesimultaneouslyintheDelta,includinghydrodynamics,nutrientconcentrations,otherwaterqualityconditions,primaryproductivity,benthicandpelagicgrazing,sedimenttransport,andothercyanobacteriaandmacrophyte‐relatedprocesses.AconsiderationofthesefactorsandtheirinteractionswillalsoprovideinsightintohowachangeinagivendriverordriverscouldaffectcyanobacteriaandmacrophytebloomsintheDelta.Throughtheuseofmodelingscenariosandsensitivityanalysis,itwillbepossibletogainanunderstandingofhowchangesinnutrientconcentrationsandforms,aswellasotherdrivers,mayimpactdrinkingwaterproblemsassociatedwithcyanobacteriaandmacrophytes.

Modeling Scenarios

Thedevelopmentofmodelingtoolstoanswernutrientmanagementquestionsisplannedtooccurintwophases.Theinitialphaseisanticipatedtobecompletedby2020or2021.ThistimeframecoincideswithexpectedchangesinthedischargeofnutrientsintotheLowerSacramentoRiverfromtheSacramentoRegionalWastewaterTreatmentPlant(SRWTP),thedischargeofnutrientsfromtheCitiesofModestoandTurlockintotheLowerSanJoaquinRiverduetotheredirectionoftheirflowstotheDeltaMendotaCanal,andthedischargeofnutrientsfromtheCityofStocktonwastewatertreatmentplantintotheSanJoaquinRiverduetotheimplementationofnewnutrientremovalprocesses(LWA2017).FuturemodelingoftheDeltaecosystemwillneedtoconsiderabaselineconditionwithrespecttonutrientinputsfromtheLowerSacramentoRiver,theLowerSanJoaquinRiver,andtheSanJoaquinRiverthatvariesfromcurrentconditions.ModelingeffortswillalsoneedtoconsideramultitudeofphysicalandbiologicalchangesexpectedtooccuriftheprojectsproposedaspartoftheBayDeltaConservationPlanareimplemented.FutureexpandedsurveillancemonitoringandresearchcomingfromimplementationoftheDeltaNutrientResearchPlanwillprovideadditionalempiricaldataandarefinedmechanisticunderstandingofDeltaprocessesthatwillneedtobeincorporatedintomodelingtools.

Onceinformationgathering,research,andmodeldevelopmenteffortsaresufficienttobeginassessingchangesinbaselineconditionsthroughspecificmanagementactions,itwillbeimportantthatmodelingscenariosappropriatelyconsiderfuturechangesinclimate,Deltahydrology,wetlandrestoration,andnutrientloading.Itwillbenecessarytodevelopmodelingscenariosthatconsiderplanned,possible,andouterboundarychangesthatcanbeproducedthroughvaryinglevelsofnutrientloadmanagementandsystemmanagement.

6.4 EFFECTIVENESS OF MANAGEMENT

Asmodeldevelopmentmatures,andmodelingscenariosarecreatedthatshowprojectedoutcomesofvariousmanagementactions,itwillbeimportanttoconsiderthefollowingaspectsofsuchmanagementactions:

Canreductionsinnutrientloadsalone,orincombinationwithothermanagementefforts,limitthegrowthandproliferationofcyanobacteriaandnon‐nativemacrophytesand,thereby,preventorsignificantlyreducetasteandodor,cyanotoxinand/ormacrophyteproblemsintheDeltaandindownstreamstorageandconveyancefacilities?

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Appendix A

A.1 THE STATE WATER PROJECT

TheSWPextendsfromthemountainsofPlumasCountyintheFeatherRiverwatershedtoLakePerrisinRiversideCounty.WaterfromthenorthDeltaispumpedintotheNorthBayAqueduct(NBA)attheBarkerSloughPumpingPlant,asshowninFigureA.1.BarkerSloughisatidallyinfluenceddead‐endsloughwhichistributarytoLindseySlough.LindseySloughistributarytotheSacramentoRiver.Thepumpingplantdrawswater fromboth theupstreamBarkerSloughwatershedand from theSacramentoRiver,viaLindseySlough.OtherlocalsloughsmayalsocontributewatertotheNBA.TheNBApipelineextends21milesfromBarkerSloughtoCordeliaForebay(Cordelia)andPumpingPlant,andthen7milestoitsterminusattwo5‐milliongallonterminaltanks.TheNBAservesasamunicipalwatersupplysourceforanumberofmunicipalitiesinSolanoandNapacounties.TheSolanoCountyWaterAgency(SCWA)andtheNapaCountyFloodControlandWaterConservationDistrict(NapaCounty)arewholesalebuyersofwaterfromtheSWP.SCWAdeliverswatertoTravisAirForceBaseandthecitiesofBenicia,Fairfield,Vacaville,andVallejo.NapaCountydeliverswatertothecitiesofNapa,andAmericanCanyon.

InthesouthernDelta,waterentersSWPfacilitiesatCliftonCourtForebay(CliftonCourt),andflowsacross the forebayabout3miles to theH.O.BanksDeltaPumpingPlant (Banks), fromwhich thewaterflowssouthwardintheGovernorEdmundG.BrownCaliforniaAqueduct(CaliforniaAqueduct).WaterisdivertedintotheSouthBayAqueduct(SBA)atBethanyReservoir,1.2milesdownstreamfromBanks.FigureA.2isamapshowingthelocationsoftheSBAfacilities.TheSBAconsistsofabout11milesofopenaqueductfollowedbyabout34milesofpipelineandtunnelservingEastandSouthBaycommunitiesthroughtheZone7WaterAgencyoftheAlamedaCountyFloodControlandWaterConservationDistrict (Zone7WaterAgency),AlamedaCountyWaterDistrict (ACWD),andSantaClaraValleyWaterDistrict(SCVWD).WaterfromtheSBAcanbepumpedintoorreleasedfromLakeDelValleattheDelVallePumpingPlant.LakeDelVallehasanominalcapacityof77,110acre‐feet,with40,000acre‐feetforwatersupply.TheterminusoftheSBAistheSantaClaraTerminalReservoir(TerminalTank).

Figure A. 1. The North Bay Aqueduct

Figure A. 2. The South Bay Aqueduct

FromBethanyReservoir,waterflowsintheCaliforniaAqueductabout59milestoO’NeillForebay,asshowninFigureA.3.TheforebayisthestartoftheSanLuisJoint‐UseFacilities,whichservebothSWPandfederalCentralValleyProject(CVP)customers.CVPwaterispumpedintoO’NeillForebayfromtheDelta‐MendotaCanal(DMC).TheDMCconveyswaterfromtheC.W.“Bill”JonesPumpingPlant(Jones)to,andbeyond,O’NeillForebay.TheO’NeillPump‐GenerationPlant(O’Neill Intake),locatedonthenortheastsideofO’NeillForebay,enableswatertoflowbetweentheforebayandtheDMC.SanLuisReservoirisconnectedtoO’NeillForebaythroughanintakechannellocatedonthesouthwest sideof the forebay.FigureA.4 is a locationmap that shows these features.Water inO’Neill Forebay can be pumped into San Luis Reservoir by the William R. Gianelli Pumping‐GeneratingPlant(Gianelli)orreleasedfromthereservoirtotheforebaytogeneratepower.SanLuisReservoir,withacapacityof2.03millionacre‐feet,isjointlyownedbytheSWPandCVP,with1.06millionacre‐feetbeingthestate’sshare.AnintakeonthewestsideofthereservoirprovidesdrinkingwatersuppliestoSCVWD.WaterentersSCVWDfacilitiesatPachecoPumpingPlant(Pacheco),fromwhichitispumpedbytunnelandpipelinetowatertreatmentandgroundwaterrechargefacilitiesintheSantaClaraValley.

Waterreleasedfromthereservoirco‐minglesinO’NeillForebaywithwaterdeliveredtotheforebaybytheCaliforniaAqueductandtheDMC,andexitstheforebayatO’NeillForebayOutlet,locatedonthesoutheastsideoftheforebay.O’NeillForebayOutletistheinceptionoftheSanLuisCanalreachoftheCaliforniaAqueduct,asshowninFigureA.5.TheSanLuisCanalextendsabout100milestoCheck21,nearKettlemanCity.TheSanLuisCanalreachoftheaqueductservesmostlyagriculturalCVP customers and conveys SWPwaters to points south. Unlike the remainder of the CaliforniaAqueduct,whichwasconstructedbythestate,theSanLuisCanalreachwasfederallyconstructedandwasdesignedtoallowdrainagefromadjacentlandtoentertheaqueduct.LocalstreamsthatruneastwardfromtheCoastalRangeMountainsbisecttheaqueductatvariouspoints.Duringstorms,waterfromsomeofthesestreamsenterstheaqueduct.Thisisgenerallynotthecasefortheotherreachesoftheaqueduct.

ThejunctionwiththeCoastalBranchoftheaqueductislocated185milesdownstreamofBanksandabout12milessouthofCheck21.TheCoastalBranchprovidesdrinkingwatersuppliestocentralCaliforniacoastalcommunitiesthroughtheCentralCoastWaterAuthority(CCWA)andtheSanLuisObispoCountyFloodControlandWaterConservationDistrict.FigureA.6isamapshowinglocationsofthesefacilities.TheCoastalBranchis115mileslong;thefirst15milesareopenaqueductandtheremainderisapipeline.

Figure A. 3. California Aqueduct between Banks Pumping Plant and San Luis Reservoir

Figure A. 4. O’Neill Forebay and San Luis Reservoir

Figure A. 5. San Luis Canal Reach of the California Aqueduct

Figure A. 6 The Coastal Branch of the California Aqueduct

FromthejunctionwiththeCoastalBranch,watercontinuessouthwardintheCaliforniaAqueductasshown inFigureA.7, providingwater to both agricultural anddrinkingwater customers in theserviceareaofKernCountyWaterAgency(KCWA).TheKernRiverIntertieisdesignedtopermitKern River water to enter the aqueduct during periods of high flow. Due to increasingly scarceCaliforniawatersupplies,theSWPisusedtoconveybothsurfacewaterandgroundwateracquiredthrough transfers andexchanges among local agencies.Mostof thenon‐Projectwater enters theaqueductbetweenCheck21andCheck41.

EdmonstonPumpingPlantisatthenorthernfootoftheTehachapiMountains.ThisfacilityliftsSWPwaterabout2000feetbymulti‐stagepumpsthroughtunnelstoCheck41,locatedonthesouthsideoftheTehachapiMountains.Aboutamiledownstream,theCaliforniaAqueductdividesintotheWestandEastBranches.TheWestBranchflows14milestoPyramidLake,thenanother17milestotheoutlet of Castaic Lake, the drinking water supply intake of the Metropolitan Water District ofSouthernCalifornia(MWDSC)andCastaicLakeWaterAgency(CLWA).PyramidLakehasacapacityof 171,200 acre‐feet and Castaic Lake has a capacity of 323,700 acre‐feet.FigureA.8 is amapshowinglocationsofWestBranchfeatures.

FromthebifurcationoftheEastandWestBranches,waterflowsintheEastBranchtohighdesertcommunitiesintheAntelopeValleyservedbytheAntelopeValleyEastKernWaterAgency(AVEK)andthePalmdaleWaterDistrict(Palmdale).FigureA.9isamapshowingEastBranchfeatures.AsinthesouthernSanJoaquinValley,groundwaterfromthelocalareahasoccasionallybeenallowedintothe aqueduct to alleviate drought emergencies.On theEastBranchnearHesperia, surfacewaterdrainagefrompartofthatcityenterstheaqueductduringstormevents.TheinlettoSilverwoodLakeislocatedonthenorthsideofthereservoirnearCheck66.SilverwoodLakehasacapacityof74,970acre‐feet and serves as adrinkingwater supply for theCrestline‐LakeArrowheadWaterDistrict(CLAWA).WaterisdrawnfromthesouthsideofthereservoirandflowsthroughtheDevilCanyonPowerplanttothetwoDevilCanyonafterbays.DrinkingwatersuppliesaredeliveredtoMWDSCandSanBernardinoValleyMunicipalWaterDistrictfromthispoint,andwaterisalsotransportedviatheSantaAnaPipelinetoLakePerris,whichistheterminusoftheEastBranch.MWDSCroutinelytakesasmallamountofwaterfromLakePerris.

Figure A. 7 California Aqueduct between Check 21 and Check 41

Figure A. 8 The West Branch of the California Aqueduct

Figure A. 9 The East Branch of the California Aqueduct

A.2 NUTRIENT CONCENTRATIONS IN THE DELTA AND SWP

Nutrientconcentrationsshowconsiderableseasonalandspatialvariability.FiguresA.10toA.17showthevariabilityinnutrientconcentrationsatHood,Vernalis,BarkerSlough,andBanksaswellastheannualandinterannualvariability.FiguresA.18andA.19showdatawhichhasbeencollectedatanumberoflocationsalongtheCaliforniaAqueductfrom2004to2010.

Figure A. 10. Total N Concentrations at Hood

Dry Years

Wet Years

Figure A. 11. Total P Concentrations at Hood

Figure A. 12 Total N Concentrations at Vernalis

Dry Years

Wet Years

Dry Years

Wet Years

Figure A. 13. Total P Concentrations at Vernalis

Figure A. 14 Total N Concentrations at Barker Slough

Dry Years

Wet Years

Dry Years

Wet Years

Figure A. 15. Total P Concentrations at Barker Slough

Figure A. 16Total N Concentrations at Banks

Dry Years

Wet Years

Dry Years

Wet Years

Figure A. 17. Total P Concentrations at Banks

Dry Years

Wet Years

Figure A. 18 Total N Concentrations in the SWP (2004-2010)

Figure A. 19 Total P Concentrations in the SWP (2004-2010)

Pacheco

O'Neill Forebay O

Check 21

Check 41

Castaic Outle

Devil Canyon

Pacheco

O'Neill Forebay O

Check 21

Check 41

Castaic Outle

Devil Canyon

A.3 CYANOBACTERIA TAXA MAKEUP

Figure A.20 Proportion of cyanobacteria genera which are responsible for producing taste and odor compounds and toxin compounds.

A.4 POTENTIAL ALGAL PRODUCTION OF SOURCE WATERS

Figure A.21 Algae production potential in Colorado River Water (CRW) versus State Water Project (SPW) based on a standard assay test using a common diatom test species Selenastrum using varying proportions of the CRW and SPW waters.

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