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StateofCaliforniaRegionalWaterQualityControlBoard FormerKastPropertyTankFarmSiteRemediationProjectSCHNo.2014031053 6‐1

6.0 COMPARISON OF ALTERNATIVES

INTRODUCTION

This chapter provides a summary comparison of the RP’s Proposed Remedy (base remedy) with theExpedited Implementation Option and a comparison of the RP’s Proposed Remedy with the threealternatives.UndertheCEQAGuidelines,theidentificationandanalysisofalternativesisafundamentalpartof the environmental reviewprocess. As discussed in Section3.1,DevelopmentofAlternatives to theRP’sProposedRemedy,ofthisEIR,theRegionalBoardconsideredofarangeofalternativesbasedoninformationfrom thepilot tests conducted at the site, information contained in theFeasibility StudyReport (FS), andindependent review of the FS and Human Health Risk Assessment by the State Office of EnvironmentalHealth Hazard Assessment (OEHHA) and the University of California Los Angeles (UCLA) Expert Panel,respectively. Selected Alternatives include (1) Alternative 1: No Project Alternative, (2) Alternative 2:Excavation Beneath Landscape and Hardscape to 10 Feet Alternative and (3) No Excavation BeneathHardscape–5FeetWithTargeted10FeetAlternative.ThesealternativesaredescribedinChapter3ofthisEIR.

In addition to providing a summary comparison of alternatives, this chapter contains an environmentallysuperior comparison of the alternatives with the RP’s Proposed Remedy. CEQA Guidelines Section15126.6(e)(2)statesthat“Iftheenvironmentallysuperioralternativeisthe“noproject”alternative,theEIRshall also identify an environmentally superior alternative among the other alternatives.” Theenvironmentally superior alternative is typically the alternative that meets the overall project goals andobjectives and can avoid or substantially lessen one ormore of the significant effects of a project whencomparedtootherprojectalternatives,includingtheNoProjectAlternative.

1. OBJECTIVES OF THE PROPOSED PROJECT

Section15124(b)oftheCEQAGuidelinesstatesthattheProjectDescriptionshallcontain“astatementoftheobjectivessoughtbytheproposedproject.”TheunderlyingpurposeoftheproposedRAPistoremediatethesite consistent with the Regional Board’s CAO R4‐2011‐0046 dated March 11, 2011, as amended, andapplicable laws and policies. In accordance with the provisions of the CAO and as required by Section15124(b)oftheCEQAGuidelines,thefollowingaretheobjectivesfortheproposedRAP:

1. ImplementaRAPthatcomplieswiththeCAOandmeetsthemedia‐specific(i.e.soil,soilvapor,andgroundwater)RemedialActionObjectives(RAOs)developedforthesite.(SeeTable6‐2foralistoftheRAOsforthesite.)

2. Maintain the residential land use of the site and avoid permanently displacing residents fromtheirhomesorphysicallydividingtheestablishedCarouselTractcommunity.

3. Minimizeshort‐termdisruptiontoresidents.

4. Allow residents the long‐term ability to safely and efficiently make improvements requiringexcavationorpenetrationintoshallowsitesoils(i.e.,landscaping,hardscape,gardening,etc.)ontheirproperties.

5. Limitorminimizeenvironmentalimpactsassociatedwiththecleanupactivities.

6.0 Comparison of Alternatives November 2014


2. SUMMARY COMPARISON

Table6‐1, Summary ofComparisonof ImpactsAssociatedwith theOptionand theAlternativesRelative toImpacts of theProject, provides a comparative summary of the environmental impacts anticipated undereachAlternativetotheenvironmentalimpactsassociatedwiththeproject.PursuanttoSection15126.6(c)oftheCEQAGuidelines,theanalysisbelowaddressestheabilityoftheAlternativesto“avoidorsubstantiallylessenoneormoreofthesignificanteffects”oftheproject.

As shown in Table 6‐1,most environmental impacts from theRP’s ProposedRemedywould be less thansignificant,asdeterminedintheanalysesinChapter5,EnvironmentalImpactAnalysis,ofthisEIR.However,impacts generated by the Expedited Implementation Option, and the three Alternatives (the No ProjectAlternative,ExcavateBeneathLandscapeandHardscapeto10FeetAlternative,andNoExcavationBeneathHardscape–5FeetWithTargeted10FeetAlternative)havethepotentialtobeincrementallygreater,less,orthe same as under the base remedywith respect to a particular threshold. The comparative differencesbetween the Expedited Implementation Option and the three alternatives are indicated as in Table 6‐1.Potentially significant environmental effects for theRP’sProposedRemedyand the three alternatives arediscussed below. In addition, a discussion regarding the ability of the alternatives to meet the projectobjectives is provided. Table6‐2, SummaryComparison of theProject’s andAlternatives’Ability toMeetProjectObjectives,summarizesthecomparison.

RP’s Proposed Remedy – Expedited Implementation Option

TheRP’sProposedRemedyincludesanExpeditedImplementationOptionthatisdescribedinChapter3andevaluated throughout Chapter 5 of this EIR. TheExpedited ImplementationOptionwould result inmoreactivity at the site as two clusterswould be remediated simultaneously. While not an alternative to theproject,acomparisonofimpactsoftheOptionrelativetotheprojectisprovidedbelowandinTable6‐1.

Aswiththebaseremedy,theExpeditedImplementationOptionwouldmeetalltheprojectobjectiveslistedabove.

Air Quality

The Expedited Implementation Option would involve approximately twice the daily activity of the RP’sProposedRemedy and, therefore,would generate approximately twice the remediation‐related emissionsassociatedwiththebaseremedyduringpeakperiods.Althoughincrementallygreaterthanunderthebaseremedy,peakemissionswouldnotexceedthresholdlevelsandwouldbelessthansignificant.AlthoughtheExpedited Implementation Option would increase daily emissions, the duration of remediation activitieswouldapproximately4yearscomparedtoapproximately6yearsundertheRP’sProposedRemedy.

Geology and Soils

The total amount of excavated soils would be the same as under the RP’s Proposed Remedy; however,excavationactivityoccurringconcurrentlywouldincreasepeakactivityandsoilsandgradingmanagement.As such, the peak potential exposure of soils to geology‐related erosion forces, would be greater. AsdescribedinSection5.2,GeologyandSoils,ofthisEIR,approvedgradingplansanderosioncontrolwouldbethesameasundertheRP’sProposedRemedyandimpactswouldbelessthansignificantHowever,impactswouldbeincrementallygreaterundertheExpeditedImplementationOptionbecauseofhigherpeakactivity.

November 2014 6.0 Comparison of Alternatives


Impactsassociatedwithseismicforces,groundstability,andexpansivesoilswouldbethesameasunderthebaseremedyandlessthansignificant.

Greenhouse Gas Emissions

TheExpeditedImplementationOptionwouldtakeapproximately4yearsandwouldrequirethesametypesofheavy‐dutyequipmentastheRP’sProposedRemedy.WhiletheExpeditedImplementationOptionwouldresult in increaseddailyactivitiesat thesite, thetotalamountofactivity(fuelandenergyuse)thatwouldgenerateGHGemissionswould remain the sameas theRP’sProposedRemedy. Therefore, theExpeditedImplementation Option would result in the same total short‐term GHG‐emitting fuel and energy use asdiscussedfortheRP’sProposedRemedy. Impactsrelatedtogreenhousegasemissionswouldbelessthansignificant.

Hazardous Materials

TheExpeditedImplementationOptionwouldresultinagreaterlevelofactivityonthesiteatonetimebutwouldnotincreasethetotallevelofactivitiessite‐wide.Byworkingonmultipleclusterssimultaneously,theExpedited ImplementationOptionwould reduce thedurationof remediationactivities toapproximately4yearscomparedtoapproximately6yearsundertheRP’sProposedRemedy.Althoughincrementallygreaterthan under the Proposed Remedy, acute (maximum hour) and chronic (annual) non‐cancer health riskswouldnotexceedthresholdlevelsandwouldbelessthansignificant. TheincrementalincreaseinlifetimecancerriskwouldbesimilartotheRP’sProposedRemedybecausetheexposuretoTACs,whichisdirectlyproportional to the amount of excavation and hauling, would be the same as under the RP’s ProposedRemedy.SimilartotheProposedRemedy,cancerhealthriskswouldbelessthansignificant.Inaddition,theriskofaccidentalreleasethroughtheroutinetransport,use,ordisposalofhazardousmaterialsandthroughreasonablyforeseeableupsetandaccidentconditionsinvolvingthereleaseofhazardousmaterialsintotheenvironment would be the same as the RP’s Proposed Remedy because the total amount of demolishedmaterialsandexcavatedsoilsandtotalnumberoftransporttrucktripswouldbethesameasundertheRP’sProposed Remedy. Similar to the Proposed Remedy, accidental release impacts would be less thansignificant.

Hydrology and Water Quality

TheExpeditedImplementationOptionwouldresultinagreaterlevelofactivityonthesiteatonetimebutwouldnot change the activity at an individual propertyor increase the level of activities site‐wide. Withacceleratedexcavationactivities,thepotentialforgreaterexposuretoerosionforces,suchasrainfall,atonetime of residual soils or replacement soils exists. As with the RP’s Proposed Remedy, the ExpeditedImplementationOptionwouldcomplywithPDFsandBMPsrelatedtoprotectionofsurfaceandgroundwaterduringexcavationandsoilreplacementand,althoughincrementallygreaterthanunderthebaseremedy,theExpeditedImplementationOptionwouldhavealessthansignificantimpactregardingremediationeffectsonwaterquality.Becauseremediationwouldoccuroverashortertimeperiodthanunderthebaseremedy,itwould improve COC conditions in a shorter time frame. The Expedited ImplementationOption have thesameeffectastheRP’sProposedRemedyregardingtherateorchangethedirectionofmovementofexistingAswiththeRP’sProposedRemedy,impactsregardinggroundwaterqualitywouldbelessthansignificant.



Noise and Vibration

TheExpeditedImplementationOptionwouldresultinagreaterlevelofactivityonthesiteonagivendaybutwould not change the level of activity at an individual property. Therefore, noise levels and vibrationassociated with demolition of hardscape and excavation would be similar within close proximity of theexcavationsiteasunderthebaseremedy.Asunderthebaseremedy,noiseandvibrationimpactswouldbepotentially significant. Mitigationmeasures involving the relocation of impacted residentswould reducenoise levels to a less than significant level. However, because such relocation would be voluntary, themitigation is not assured. Therefore, as with the base remedy, noise and vibration impacts would beconservativelyconsideredtobepotentiallysignificantandunavoidable.

Traffic and Circulation

Expedited Implementation Option excavation activities would be accelerated and implementation wouldoccur by the end of 2019, approximately two years less than under the basic remedy. The ExpeditedImplementationOptionwouldgenerate790totaldailytrips(comparedto478underthebasicproject)and94tripsduringeachA.M.andP.M.peakhour(comparedto61underthebasicproject).TotaldailyPCEtrucktripswouldbe604(comparedto478underthebasicproject)andA.M.andP.M.peakhourtrucktripswouldbe57(comparedto38under thebasicproject). Although tripgenerationandpeakhourtrafficwouldbeincrementally greater thanunder the base remedy, theExpedited ImplementationOptionwould result inlessthansignificantimpactsatthe14studyintersections.

Utilities and Service Systems (Solid Waste)

The Expedited Implementation Optionwould increase daily demolition and excavation at twice the dailyactivity rate as the base remedy (586 CY per day compared to 293 CY per day under the base remedy).Projectpeaksolidwastedailyexportsunderthebaseremedywouldbe293CYofexcavatedsoils,60CYofgreenwaste,and56CYofinertconstructionmaterials. UndertheExpeditedImplementationOption,dailysolid waste exports would be 586 CY of excavated soil, 120 CY of green waste, and 112 CY of inertconstructionmaterials. However,totalexcavatedsoil,inertconstructiondebris,andgreenwastewouldbethe same as under the base remedy and would not exceed the daily capacities of treatment or disposalfacilities. As under the base remedy, treated excavated soils and greenwastewould not be deposited inlandfills,norwouldtheyimpactlandfillcapacities.InertconcreteandasphaltwastewouldbeprocessedattheCoppfacilityandwouldnotexceedthecapacityof the facility. Thevolumeofother inertconstructiondebris items (such as fencing) would beminor compared to the County’s capacity to receive these inertmaterials. Inertdebriscanbemanagedat theAzusaLandReclamationLandfilloranIDEFO. Becausethefacilities would have the daily and long‐term capacity to receive the Expedited Implementation Option’sconstruction debris disposal demand, as with the base remedy, solid waste impacts would be less thansignificant.

Alternative 1: No Project Alternative

UnderAlternative1,NoProjectAlternative,theexistingconditionswouldremainandtheRAPwouldnotbeimplementedatthesite.NoexcavationwouldoccurandnoSVEwellsandSVEsystemorsub‐slabmitigationwould be installed. However, monitoring of the site would continue. All existing site features, such asresidences, landscaping,hardscape,fences,patios,andancillarystructureswouldremain. Norelocationofresidentswouldoccur.Inotherwords,theresidentialsubdivisionwouldremainasitcurrentlyexiststodaywithout remediation of site impacts. A comparison of the No Project Alternative’s impacts to the base



remedyispresentedbelow.AlthoughtheNoProjectAlternativewouldavoidtheRAP’slessthansignificanteffects,thisAlternativewouldnotmeetthestatutoryrequirementsoftheRAPortheprojectobjectiveslistedabove.

Air Quality

TheNoProjectAlternativewouldnot involveanyexcavationof soilsorchange toexistingconditions thatwouldresultinnewsourcesofemissionsoremissionscontrolsatthesite.TheNoProjectAlternativewouldavoid the excavation‐related impacts associated with the use of heavy equipment needed for theimplementation of the RAP. Therefore, the No Project Alternative would avoid the less than significantemissionsthatwouldoccurundertheRP’sProposedRemedy.

Geology and Soils

The No Project Alternative would not involve any excavation of soils or changes to existing groundconditions thatwould requiregradingpermitsorgeotechnical analysisof activities at the site andwould,thus, avoid any potential excavation‐related impacts associated with peak potential exposure of soils togeology‐relatederosion forces , suchas seismicevents,whichweredetermined tobe less thansignificantunder the RP’s Proposed Remedy with the implementation of project design features. This Alternativewouldhavenoimpactrelativetoseismicforces,groundstability,andexpansivesoilscomparedtoalessthansignificantimpactunderthebaseremedy.


TheNoProjectAlternativewouldnotinvolveanyexcavationofsoilsorchangestoexistingconditionsthatwould result in new sources of GHG emissions at the site. The No Project Alternative would avoid anypotentialGHGexcavation‐relatedimpacts,whichweredeterminedtobelessthansignificantundertheRAPwiththeimplementationofPDFs.

Hazardous Materials

TheNoProjectAlternativewouldnotresultinthereleaseofTACsfromremediationactivities,andthereforewould not create a significant hazard to the public or environment through the routine transport, use ordisposal of hazardousmaterials during excavation and hauling, because these activitieswould not occur.However the No Project Alternative would not fulfill the requirements of the CAO. The No ProjectAlternative would avoid the RP’s Proposed Remedy’s less than significant impacts related to short‐termexposureofTACsfromremediationofthesiteandwouldavoidthelessthansignificantriskofupsetrelatedtothetransportofimpactedmaterialfromthesite.However,theNoProjectAlternativewouldfailtoreducethelong‐termriskofexposuretoresidentsandon‐siteutilityworkersandlongtermriskswouldremainthesame as existing conditions. Therefore, overall impacts under theNo Project Alternativewith respect tohazardousmaterialswouldbelessthanundertheRP’sProposedRemedy.


TheNoProjectAlternativewouldnotinvolveanyexcavationand,therefore,wouldavoidanypotentialdirectcontact between contaminatedmaterials and on‐ or off‐site surfacewater thatwould occur as a result ofexcavation.However,thisAlternativewouldnotprovideforSVE/bioventing,whichisintendedtopromotedegradation of residual hydrocarbon concentrations in soils, or for excavation of COC‐containing soils.



Therefore the benefit of bioventing in concertwith SVE to increase oxygen levels in subsurface soils andpromote microbial activity and degradation of longer‐chain petroleum hydrocarbons would not occur.BecauseCOC‐containingsoilswouldnotberemovedorvented, thepotential for runoff (surfacewater) toenterandflowoutofthesematerialswouldcontinueasunderexistingconditions. Assuch,surfacewaterwouldpotentiallyviolate regulatory standards, asdefined in theapplicableNPDESstormwaterpermit forthereceivingwaterbody.ImpactswithrespecttosurfacewaterqualitywouldbepotentiallysignificantandgreaterthanthelessthansignificantwaterqualityimpactsundertheRP’sProposedRemedy.

Noise and Vibration

TheNoProjectAlternativewouldnotinvolveanyremediationoroperationactivitiesatthesiteandwould,therefore, avoid any potential remediation noise and vibration impacts. Therefore, the No ProjectAlternativewouldavoidthepotentiallysignificantandunavoidablenoiseandvibrationimpactsthatwouldoccurundertheRP’sProposedRemedy.


TheNoProjectAlternativewouldnotinvolveanyexcavationorconstructionactivitiesand,thus,wouldnotresult in generation of additional vehicle trips relative to existing conditions. TheNoProject Alternativewould not affect the function of the local and regional traffic network. Because no remediation orconstructiontrafficwouldbegeneratedthisAlternativewouldhavelessimpactthanthelessthansignificantimpactsthatwouldoccurundertheRP’sProposedRemedy.


TheNo Project Alternativewould not involve any removal of hardscape, excavation of soils or change toexisting ground conditions that would require disposal of materials at any facilities. Therefore, the NoProjectAlternativewouldavoidthelessthansignificantimpactsthatwouldoccurundertheRP’sProposedRemedy.

Relationship of the Alternative to Project Objectives

Table6‐2,SummaryComparisonoftheProjectandAlternativesAbilitytoMeetProjectObjectives,summarizestherelationshipoftheNoProjectAlternativetotheobjectivesoftheRP’sProposedRemedy. AsshowninTable6‐2,theNoProjectAlternativewouldnotimplementtheRAPormeetlong‐termobjectivesoftheRP’sProposed Remedy, including Objective 1 to implement a RAP that complieswith the CAO andmeets themedia‐specificRAOsdevelopedforthesiteandObjective4toallowresidentsthelong‐termabilitytosafelyand efficiently make improvements requiring excavation or penetration into site soils (i.e., landscaping,hardscape,gardeningetc.)on theirproperties. TheNoProjectAlternativewouldmaintain theresidentialland use of the site and would avoid permanently displacing residents from their homes or physicallydividing the established Carousel Tract community (Objective 2); however, because the No ProjectAlternativewould not provide for remediation, this Alternativewould notmeet the long term objectives.However,becausenoexcavationassociatedwithremediationwouldoccur,theNoProjectAlternativewouldminimize short‐term disruption to residents (Objective 3) and would limit or minimize environmentalimpactsassociatedwiththecleanupactivities.However,becauseitwouldnotresultinremediation,theNoProjectAlternativeisconsideredtonotmeettheprimaryobjectiveoftheRP’sProposedRemedy.



Alternative 2: Excavation Beneath Landscape and Hardscape to 10 Feet Alternative

Alternative 2would include the same remedial technologies as the project, butwould excavate soils to adepthof10feetbelowgroundsurface(bgs)at224residentialproperties(comparedto5feetwithtargetedexcavation to 10 feet bgs at 219 residential properties under the RP’s Proposed Remedy). Alternative 2would require on average, excavation of 1,222 CY of soil per property (compared to 611 to 867 CY perproperty under the RP’s Proposed Remedy). Approximately 274,700 CY of impacted soils would beexcavated from the residential properties and approximately 43,900 CY of impacted soils would beexcavatedfromotherareasonthesite.Alternative2wouldresultinthehaulingofapproximately318,600CY of impacted soil (compared to approximately 186,090 CY under the RP’s Proposed Alternative).Alternative 2would occur over an approximately 7.8‐year timeframe, compared to approximately 6‐yeartimeframeundertheRP’sProposedRemedy.AswiththeRP’sProposedRemedy,Alternative2wouldmeetalltheprojectobjectiveslistedabove.

Air Quality

Alternative 2 would involve the same daily demolition and excavation volumes, truck trips, and workercommutesasanticipatedundertheRP’sProposedRemedy(baseremedy).Therefore,peakemissionswouldbethesameasunderthebaseremedy.AswiththeRP’sProposedRemedy,airqualityimpactswouldbelessthansignificant.

Geology and Soils

Alternative2wouldincreasethenumberofpropertiesbeingremediatedfrom219(undertheRP’sProposedRemedy)to224andthetotalexcavatedsoil(318,600CYcomparedto186,090CYundertheRP’sProposedRemedy).Excavationsto10feetbgswouldrequireincrementallymoreshoringofcutareas,setbacksfromstructures, and other supports compared to shallower excavations under the RP’s ProposedRemedy. Aswith the RP’s Proposed Remedy, geologic hazards from seismic forces, landslides, settlement, or slippagewould be less than significant. Although daily impacts would be the same as under the RP’s ProposedRemedy,thegreaterdurationofactivity(approximately7.8yearscomparedtoapproximately6yearsunderthe RP’s Proposed Remedy), potential for exposure of soils to geology‐related erosion forces would begreater. Although erosion control and implementation of approved grading plans would be the same asunder the RP’s Proposed Remedy and impacts would be less than significant, impacts would beincrementallygreaterunderAlternative2becauseofthelongerremediationtimeframe.Impactsassociatedwithseismicforces,groundstability,andexpansivesoilswouldbethesameasunderthebaseremedyandlessthansignificant.


Alternative 2 would take approximately 7.8 years and would require the same types of heavy‐dutyequipmentastheRP’sProposedRemedy.Alternative2hasthepotentialtocreateshort‐termGHGimpactsthroughtheuseofheavy‐dutyconstructionequipmentandthroughvehicletripsgeneratedfromhaultrucks,vendor trucks, and remediationworkers and visitors traveling to and from the site. Daily activity levelsunder this Alternative would be the same as the project. Remedial activities would occur for a greaternumberofdaysoveralltoaccountfortheadditionalexcavatedmaterialandwouldbegreaterthanundertheRP’sProposedRemedy.AlthoughAlternative2wouldnotexceedthresholdstandardspertinenttoGHGandwould have a less than significant impact related to GHG emissions, would require the use of additionaltransportationfuelstotransporttheincreasedamountsofexcavationandbackfillmaterialstoandfromthe



siteascomparedtotheRP’sProposedRemedy.Fromatransportationenergyperspective,thisAlternativewouldbe lessefficient thantheRP’sProposedRemedydueto theneedto transportmaterials thatdonotwarrantexcavationaspertheSSCGs.

Hazardous Materials

Alternative 2would result in a greater increase in short‐termTAC emissions andpotential for accidentalreleasecomparedtotheRP’sProposedRemedybecauseofthelongerperiodrequiredforremediationandincreaseinmaterialstobeexcavatedandhauled.ThisAlternativewouldincorporatethesamePDFsastheRP’sProposedRemedy,whichwould reduce short‐termemissions fromheavy equipment, trucks, fugitivedustandvolatiles.However,Alternative2wouldresultinanincreaseinshort‐termexposurewhichwouldincreaselifetimecancerrisksforsensitivereceptors. Becauseofthegreatervolumeofexcavatedsoilsanddurationofexcavationandhauling,short‐termimpactsrelatedtohealthriskwouldbegreaterthanunderthe RP’s Proposed Remedy. Given the increase in duration and activities, health risks resulting fromAlternative 2would be proportionally larger than those predicted under theRP’s ProposedRemedy, andimpactswouldbepotentiallysignificantrequiringtheimplementationofmitigationmeasures. MMHAZ‐1,MMHAZ‐2andMMHAZ‐3,asdescribedinSection5.4,HazardousMaterials,ofthisEIRwouldreducehealthrisksresultingfromAlternative2tolessthansignificantlevels.

As with the RP’s Proposed Remedy, Alternative 2 would result in restoration of affected properties andinfrastructure, including yards, landscaping, and streets. Following implementationof theRAP,negligiblelong‐termemissionswould result from theSVE/bioventing system, sub‐slabvapormitigation system,andfrom periodic monitoring and maintenance activities, as under the RP’s Proposed Remedy. Therefore,Alternative 2 would result in less than significant impacts with regard to hazards to the public orenvironmentandhazardsimpactswouldbeless(benefitswouldbegreater)thanundertheRP’sProposedRemedy.


Alternative2wouldresult in thesame levelofdailyactivityonthesiteas theRP’sProposedRemedy. AswiththeRP’sProposedRemedy,Alternative2wouldcomplywithPDFsandBMPsrelatedtoprotectionofsurfaceandgroundwaterduringexcavation.Thus,dailywaterqualityimpactswithrespecttotheeffectsofremediationsoilswouldbethesameasundertheRP’sProposedRemedyandlessthansignificant.However,remediationwould occur over a longer time period than under the RP’s Proposed Remedy and, as such,potentialexposureofsoilstosurfacewaterduringremediationwouldbeincrementallygreater.WithregardtoCOCsthatcouldentergroundwater,Alternative2wouldremoveincrementallymoreCOC‐containingsoilthanundertheRP’sProposedRemedy.However,becauseCOC’swouldberemoved,aswithRP’sProposedRemedy,effectswithrespecttothedirectionofmovementofexistingCOCsorexpansionoftheareaaffectedbyCOCswouldbelessthansignificant.

Noise and Vibration

Alternative2wouldresult in thesamedailyactivityasunder theRP’sProposedRemedyand,aswith theRP’s Proposed Remedy, would intermittently exceed the significance threshold of 65 dBA, Leq at noise‐sensitivereceptorlocations. Therefore,noiseandvibrationlevelsassociatedwithdemolitionofhardscapeandexcavationwouldbesimilarwithincloseproximityoftheexcavationsiteasunderthebaseremedy.Asunderthebaseremedy,noiseandvibration impactswouldbepotentiallysignificant. Mitigationmeasures



involving the relocation of impacted residents would reduce noise and vibration levels to a less thansignificant level. However, because such relocation would be voluntary, the mitigation is not assured.Therefore, as with the base remedy, noise and vibration impacts under Alternative 2 would beconservativelyconsideredtobepotentiallysignificantandunavoidable.


Alternative 2 would result in the same daily peak hour activity and traffic as under the RP’s ProposedRemedy. Therefore, traffic impacts,whichwouldbe less thansignificant,wouldbethesameasunder theRP’sProposedAlternative.


Alternative 2 would have the same daily demolition and excavation rates as under the RP’s ProposedRemedy. However, totalexcavatedsoilswouldbegreater(a totalof318,600CYcomparedto186,090CYundertheRP’sProposedAlternative).TotalgreenwasteandinertconstructiondebriswouldbethesameasundertheRP’sProposedRemedy.Aswiththebaseremedy,excavatedsoilwouldbetreated(cleaned)attheSoilSafefacilityinAdelanto,Californiaorsimilarfacility.Theanticipateddemand(293CYperday)wouldnotexceedtheAdelantofacility’streatmentcapacityof1,096CYperday.Asunderthebaseremedy,treatedexcavated soils and green waste would not be deposited in landfills, nor would they impact landfillcapacities. InertconcreteandasphaltwastewouldbeprocessedattheCoppfacilityandwouldnotexceedthecapacityofthefacility.Thevolumeofotherinertconstructiondebrisitems(suchasfencing)wouldbeminorcomparedtotheCounty’scapacitytoreceivetheseinertmaterials.InertdebriscanbemanagedattheAzusaLandReclamationLandfilloranIDEFO.AswiththeRP’sProposedRemedy,impactsrelativetosolidwastewould be less than significant. However, because outputwould be greater, impacts to solidwastefacilitieswouldbeincrementallygreater.


Table6‐2,SummaryComparisonoftheProjectandAlternativesAbilitytoMeetProjectObjectives,summarizesthe relationship of Alternative 2 to the objectives of the RP’s ProposedRemedy. As shown in Table 6‐2,Alternative 2 would meet long‐term objectives of the RP’s Proposed Remedy, including Objective 1 toimplement a RAP that complieswith the CAO andmeets themedia‐specific RAOs developed for the site;Objective2tomaintaintheresidentiallanduseofthesiteandavoidpermanentlydisplacingresidentsfromtheir homes or physically dividing the established Carousel Tract community; and Objective 4 to allowresidents the long‐term ability to safely and efficiently make improvements requiring excavation orpenetrationintoshallowsitesoilsontheirproperties.Alternative2wouldresultingreatershort‐termTACemissions associatedwith excavation and haul trips, resulting in TAC emissions and potential accidentalrelease, than under the RP’s Proposed Alternative. Because of greater short‐term excavation activity,hauling,anddurationoftheseactivitiesthanundertheRP’sProposedRemedy,Alternative2wouldnotmeetObjective3tominimizeshort‐termdisruptiontoresidentsorObjective5tolimitorminimizeenvironmentalimpactsassociatedwiththecleanupactivitiestothesameextentastheRP’sProposedRemedy. However,Alternative 2would bettermeet Objective 1 to implement a RAP that complieswith the CAO andmeetsmediaspecificRAOsandObjective4 toallowresidentsthe long‐termabilitytosafelyandefficientlymakeimprovementsrequiringexcavationorpenetrationintoshallowsitesoilstoagreaterextentthanundertheRP’sProposedRemedy.



Alternative 3: No Excavation Beneath Hardscape – 5 Feet With Targeted 10 Feet

Alternative

Alternative3wouldincludethesameremedialtechnologiesastheRP’sProposedRemedy,butwouldavoidexcavating below hardscape features, such as sidewalks. Approximately 92,150 CY of impacted soil(comparedtoapproximately186,090CYundertheRP’sProposedRemedy)wouldbeexcavated.Alternative3wouldoccuroveranapproximately4‐yeartimeframe,comparedtoapproximately6‐yeartimeframeundertheRP’sProposedRemedy. Aswith theRP’sProposedRemedy,Alternative3wouldmeet all theprojectobjectiveslistedabove.

Air Quality

Alternative 3 would involve the same daily demolition and excavation volumes, truck trips, and workercommutesasanticipatedundertheRP’sProposedRemedy(baseremedy).Therefore,peakemissionswouldbethesameasunderthebaseremedy.AswiththeRP’sProposedRemedy,airqualityimpactswouldbelessthansignificant.

Geology and Soils

AswiththeRP’sProposedRemedy,geologichazardsfromlandslides,settlement,orslippagewouldbelessthan significant. Daily excavation activities would be the same as under the RP’s Proposed Remedy;however,theshorterdurationofactivity(approximately4yearscomparedtoapproximately6yearsundertheRP’sProposedRemedy),potential forexposureofsoils toerosion forces,suchassiltationorslumpingwould be less. As with the RP’s Proposed Remedy, geologic hazards from seismic forces, landslides,settlement,orslippagewouldbelessthansignificant. Althoughdailyimpactswouldbethesameasunderthe RP’s Proposed Remedy, the shorter duration of activitywould incrementally reduce the potential forexposureofsoilstogeology‐relatederosionforces.Impactsassociatedwithseismicforces,groundstability,andexpansivesoilswouldbethesameasunderthebaseremedyandlessthansignificant.


Alternative3wouldtakeapproximately4yearsandwouldrequirethesametypesofheavy‐dutyequipmentastheRP’sProposedRemedy.Alternative3hasthepotentialtocreateshort‐termGHGimpactsthroughtheuse of heavy‐duty construction equipment and through vehicle trips generated from haul trucks, vendortrucks,andremediationworkersandvisitorstravelingtoandfromthesite.DailyactivitylevelsunderthisAlternativewouldbethesameastheproject.RemedialactivitieswouldoccurforfewerdaysoverallbecauseoflessexcavatedmaterialandwouldbelessthanundertheRP’sProposedRemedy.Alternative3wouldnotexceedthresholdstandardspertinenttoGHGandwouldhavealessthansignificantimpactrelatedtoGHGemissions.However,becauseitwouldrequiretheuseoflesstransportationfueltotransporttheincreasedamountsofexcavationandbackfillmaterials toandfromthesite, thisAlternativewouldbemoreefficientthantheRP’sProposedRemedyfromatransportationenergyperspective.

Hazardous Materials

Alternative3wouldresultinlessshort‐termTACemissionsandpotentialforaccidentalreleasecomparedtotheRP’sProposedRemedybecauseof theshorterperiodrequiredforremediationandreducedvolumeofmaterial excavated and hauled. This Alternativewould incorporate the same PDFs as the RP’s Proposed



Remedy, which would reduce short‐term emissions from heavy equipment, trucks, fugitive dust andvolatiles. Alternative 3 would result in a reduction in short‐term exposurewhichwould reduce lifetimecancer risks for sensitive receptors. Because of the reduced volume of excavated soils and duration ofexcavation and hauling, short‐term impacts related to health risk would be less than under the RP’sProposedRemedyandwouldbelessthansignificant.

As with the RP’s Proposed Remedy, Alternative 3 would result in restoration of affected properties andinfrastructure, including yards, landscaping, and streets. Following implementationof theRAP,negligiblelong‐termemissionswould result from theSVE/bioventing system, sub‐slabvapormitigation system,andfrom periodic monitoring and maintenance activities, as under the RP’s Proposed Remedy. Therefore,althoughAlternative3wouldresultinlessthansignificantimpactswithregardtohazardstothepublicorenvironment,impactswouldbegreater(benefitswouldbeless)thanundertheRP’sProposedRemedy.


Alternative3wouldresult in thesame levelofdailyactivityonthesiteas theRP’sProposedRemedy. AswiththeRP’sProposedRemedy,Alternative3wouldcomplywithPDFsandBMPsrelatedtoprotectionofsurface and groundwater during excavation. Thus, water quality impacts with respect to the effects ofremediationsoilswouldbethesameasundertheRP’sProposedRemedyandlessthansignificant.However,remediationwould occur over a shorter timeperiod thanunder theRP’s ProposedRemedy and, as such,potentialexposureofsoilstosurfacewaterduringremediationwouldbeincrementallyless.WithregardtoCOCs that could enter groundwater, because COC’s would be removed, as with RP’s Proposed Remedy,effectswithrespecttothedirectionofmovementofexistingCOCsorexpansionoftheareaaffectedbyCOCswouldbelessthansignificant.

Noise and Vibration

Alternative3would involveexcavationactivitysimilartotheRP’sProposedRemedyand,aswiththeRP’sProposedRemedy,would intermittentlyexceedthesignificancethresholdof65dBA,Leqatnoise‐sensitivereceptor locations. Alternative 3 has the potential to increase noise levels compared to the existingenvironment through the use of heavy‐duty construction equipment and through vehicle trips generatedfromhaultrucks,vendortrucks,remediationworkers,andvisitorstravelingtoandfromthesite.However,because concrete saws, jack hammers, other equipment to remove hardscape and concretemixer truckswould not be utilized during the residential property excavation phase, remediation activity noise levelswouldbereducedbyapproximately10dBAduringtheresidentialremediationphasecomparedtotheRP’sProposedRemedy. Remedialactivitieswouldalsooccurforafewernumberofdaysoveralltoaccountforlessexcavatedmaterial. SimilartotheRP’sProposedRemedy,peaknoiseimpactsunderAlternative3arepredictedtoresultduringthestreettrenchingphase.Noiseresultingfromthisphasewouldintermittentlyexceedthesignificancethresholdof65dBA,Leqatnoise‐sensitivereceptor locations. Mitigationmeasuresinvolving the relocation of impacted residents would reduce noise and vibration levels to a less thansignificant level. However, because such relocation would be voluntary, the mitigation is not assured.Therefore, as with the base remedy, noise and vibration impacts under Alternative 3 would beconservativelyconsideredtobepotentiallysignificantandunavoidable.

Residents immediately adjacent to a property with active remedial activity would experience vibrationvelocitiesinexcessofthehumanannoyancethresholdfromtheminiexcavator.AswiththeRP’sProposedRemedy,impactsassociatedwithvibrationwouldbelessened,butwouldstillremainsignificantunderthis



Alternative.Unlessrelocationwereacceptedasamitigationoptionbyaffectedresidents,vibrationimpactswouldnotbereducedtobelowalevelofsignificance.


Alternative 3 would result in the same daily peak hour activity and traffic as under the RP’s ProposedRemedy. Therefore, traffic impacts,whichwouldbe less thansignificant,wouldbethesameasunder theRP’sProposedRemedy.


Alternative 3 would have similar daily demolition and excavation rates to those of the base remedy.However,totalexcavatedsoilswouldbeless(atotalof92,150CYcomparedto186,090CYunderthebaseremedy).Also,becausehardscape,suchassidewalks,driveways,andpatios,wouldnotbedemolished,totalinertconstructiondebriswouldbeconsiderablyreduced.Totalgreenwastewouldbethesameasunderthebaseremedy.Asunderthebaseremedy,treatedexcavatedsoilandgreenwastewouldnotbedepositedinlandfills,norwouldtheyimpactlandfillcapacities.Thevolumeofinertconstructiondebris,suchasfencing,would beminor compared to the County’s capacity to receive these inertmaterials. Inert debris can bemanagedattheAzusaLandReclamationLandfilloranIDEFO. TheminimalquantityofinertdebriswouldnotaffecttheCounty’scapacity. ImpactswithregardtosolidwastewouldbelessthantheundertheRP’sProposedRemedyandwouldbelessthansignificant.


Table6‐2,SummaryComparisonoftheProjectandAlternativesAbilitytoMeetProjectObjectives,summarizesthe relationship of Alternative 3 to the objectives of the RP’s ProposedRemedy. As shown in Table 6‐2,becauseAlternative3wouldrequire less intensiveexcavation thanunder theRP’sProposedRemedyand,therefore,reduceoverallremediationimpacts,itwouldmeetObjective3tominimizeshort‐termdisruptiontoresidents;Objective2 tomaintain theresidential landuseof thesiteandavoidpermanentlydisplacingresidentsfromtheirhomesorphysicallydividingtheestablishedCarouselTractcommunity;andObjective5to limitorminimizeenvironmental impactsassociatedwith thecleanupactivities toagreaterextent thanundertheRP’sProposedRemedy.AlthoughitisanticipatedthatAlternative3wouldmeettheobjectivesoftheproject,suchasObjective1toimplementaRAPthatcomplieswiththeCAOandmeetsthemedia‐specificRAOsdevelopedforthesiteandObjective4toallowresidentsthelong‐termabilitytosafelyandefficientlymake improvements requiring excavation or penetration into shallow site soils on their properties.Alternative3wouldnotmeetObjectives1and4tothesameextentastheRP’sProposedRemedy.

3. ENVIRONMENTALLY SUPERIOR ALTERNATIVE

CEQAGuidelines section 15126.6(e)(2) states that “If the environmentally superior alternative is the “noproject” alternative, the EIR shall also identify an environmentally superior alternative among the otheralternatives.” The environmentally superior alternative is typically the alternative thatmeets the overallprojectgoalsandobjectivesandcanavoidorsubstantiallylessenoneormoreofthesignificanteffectsofaprojectwhencomparedtootherprojectalternatives, includingtheNoProjectAlternative. WithrespecttoidentifyinganEnvironmentallySuperiorAlternativeamongthoseanalyzedinthisEIR,therangeoffeasiblealternativesconsideredincludesAlternative1,theNoProjectAlternative;Alternative2,ExcavationBeneath



LandscapeandHardscapeto10FeetAlternative;andAlternative3,NoExcavationBeneathHardscape–5FeetWithTargeted10FeetAlternative.

Table 6‐1, Summary of Comparison of ImpactsAssociatedwith theOption and theAlternativesRelative toImpacts of the Project, provides a summary comparison of the impacts associated with the ExpeditedImplementation Option and the impacts of the project as well as with each of the alternatives and theimpactsoftheproject.AcomparativesummaryoftheabilityoftheprojectandtheAlternativestomeetthestated objectives of the project is provided in Table 6‐2, Summary Comparison of the Project’s andAlternatives’AbilitytoMeettheProjectObjectives.

TheNoProjectAlternativeisnottheenvironmentallysuperioralternativebecauseitwouldnotresultintheremovalofanywastefromthesite,andtherefore,wouldnotachievetheproject’sunderlyingpurpose,whichis toremediatethesiteconsistentwiththeRegionalBoard’sCAOR4‐2011‐0046datedMarch11,2011,asamended. While the No Project Alternative would reduce the short‐term environmental impacts whencomparedtotheRP’sProposedRemedy,siteremediationwouldnotoccurundertheNoProjectAlternative.Thus,existinghazardsandhealthriskeffectsoccurringunderexistingconditionswouldcontinue.Nolong‐term benefits to the environment or the surrounding community would occur under the No ProjectAlternative.

Alternative 2 is not environmentally superior to the RP’s Proposed Remedy with respect to short‐termimpacts(i.e.,hazards,noiseandvibration)associatedwithexcavationandhaulingsinceAlternative2wouldrequire a greater volume of excavation andwould require a longer time period for completion than theproject. Alternative2 isnotenvironmentallysuperiorwithrespect togreenhousegasemissions,hazards,andnoiseandvibration. Alternative2wouldresult ingreatergreenhousegasemissionsaswellasshort‐term TAC emissions associatedwith excavation and haul trips, andwould result in greater potential foraccidental release (related to hazards), thanunder theRP’s ProposedRemedy. In addition,Alternative 2wouldnotreduceormitigate thesignificantandunavoidablenoiseandvibration impactsof theproposedproject.Alternative2wouldnotmeetsomeoftheobjectivesoftheproject,suchasObjective3tominimizeshort‐termdisruption to residentsandObjective5 to limitorminimizeenvironmental impactsassociatedwith thecleanupactivities to thesameextentas theRP’sProposedRemedy. With theremovalofgreatervolumesofCOCstheSVE/bioventingsystemwouldlikelybeoperationalforashorterperiodoftime.Thus,Alternative2wouldmeetObjective1toimplementaRAPthatcomplieswiththeCOAandmeetsthemedia‐specific RAOs and Objective 4 to allow residents the long‐term ability to safely and efficiently makeimprovements requiring excavation or penetration into shallow site soils on their properties to a greaterextentthantheRP’sProposedRemedy.Becausetheseobjectivesapplytolong‐termenvironmentaleffects,Alternative2wouldhaveagreater long‐termbeneficialeffectandwouldmeettheprimarypurposeoftheRAPtoagreaterextentthantheRP’sProposedRemedy.

Alternative3 isenvironmentallysuperior to theproposedprojectwithrespect to impactsassociatedwithexcavationbecauseitwouldresultinlessnoise,vibrationandshort‐termhazardsassociatedwithexcavationand hauling since Alternative 3 would not result in the removal of hardscape on residential properties.Therefore,Alternative3wouldrequirelessexcavationandashortertimeperiodforcompletioncomparedwiththeproject. However,Alternative3wouldnotreduceormitigateallof the impactsof theproposedproject and stillwould result in significant and unavoidable impactswith respect to noise and vibration.Alternative3wouldmeetObjective3tominimizeshort‐termdisruptiontoresidentsandObjective5tolimitorminimizeenvironmentalimpactsassociatedwiththecleanupactivitiestoagreaterextentthantheRP’sProposedRemedy.WhileAlternative3wouldmeetObjective1toimplementaRAPthatcomplieswiththe



CAOandmeetsthemedia‐specificRAOsandObjective4toallowresidentsthelong‐termabilitytosafelyandefficiently make improvements requiring excavation or penetration into shallow site soils on theirproperties, Alternative 3 would do so to a lesser extent than the RP’s Proposed Remedy. Therefore,Alternative3wouldpotentiallyresultinagreaterriskoflong‐termexposurethanundertheRP’sProposedRemedy.



Table 6‐1

Summary of Comparison of Impacts Associated with the Option and the Alternatives Relative to Impacts of the Project

Impact Threshold RP’s Proposed Remedy Alternative 1 Alternative 2 Alternative 3

Base Remedy

Expedited Implementation

Option

No Project Alternative

Excavation Beneath Landscape and

Hardscape to 10 Feet Alternative

No Excavation Beneath Hardscape – 5 Feet With Targeted 10 Feet Alternative

Air Quality

Conflictwithorobstructimplementationoftheapplicableairqualityplan

LessthanSignificant Similar(LessthanSignificant)

Less(NoImpact) Similar(LessThanSignificant)

Similar(LessThanSignificant)

Violateanyairqualitystandardorcontributesubstantiallytoanexistingorprojectedairqualityviolation

LessthanSignificant Greater(LessthanSignificant)



Cumulativelyconsiderablenetincreaseofanycriteriapollutantforwhichtheregionisnon‐attainment




Exposesensitivereceptorstosubstantialpollutantconcentrations




Objectionableodorsaffectingasubstantialnumberofpeople




ConflictwithorobstructimplementationoftheapplicablepoliciesintheCityofCarsonGeneralPlanAirQualityElement





Table 6‐1 (Continued)

Comparison of Alternatives



Base Remedy


Option





Geology and Soils

Exposepeopleorstructurestopotentialsubstantialadverseeffects,includingtheriskofloss,injuryordeath,involving:(1)Strongseismicgroundshaking,or(2)Seismic‐relatedgroundfailure,includingliquefaction

LessthanSignificant Similar(LessThanSignificant)



Geologicunitorsoilthatisunstable,orthatwouldbecomeunstable



Similar(Less ThanSignificant)

Soilerosionorlossoftopsoil LessthanSignificant Greater(LessthanSignificant)

Less(NoImpact) Greater(LessthanSignificant)

Less(LessthanSignificant)

Expansivesoil LessthanSignificant Similar(LessThanSignificant)




Generategreenhousegasemissionsthatwouldexceed10,000MTCO2eperyear




ConflictwiththegreenhousegasemissionsreductionsgoalsandstrategiesofAB32









Base Remedy


Option





Hazardous Materials

Resultinanincrementalincreaseincumulativelifetimepotentialcancerriskfromexposuretoproject‐relatedTACsandCOCsemittedasadirectresultofimplementationoftheRAPinexcessofoneinonemillion(1x10‐6),orinexcessof10inonemillion(1x10‐5)ifBestAvailableControlTechnologies(BACT)areimplemented


Less(NoImpact) Greater(LessthanSignificantwithMitigationMeasures)


ResultinanincrementalincreaseincumulativelifetimepotentialcancerriskfromexposuretoCOCsinsoil,soilvapor,andindoorairforresidencesinexcessof1x10‐6andforon‐siteconstructionandutilitymaintenanceworkersanincrementalincreaseincumulativelifetimepotentialcancerriskoutsideoftheNCPriskrangeof1x10‐6to1x10‐4


Greater(LessthanSignificant)








Base Remedy


Option





Resultinachronicoracutenon‐cancerhazardindex(HI)ofgreaterthan1.0





InaccordancewiththeSSCGs,createconditionsleadingto,orotherwiseallowing,buildinginteriorstoaccumulateandorbeexposedtomethaneconcentrationsexceeding5percentoftheLowerExplosiveLimit(LEL)formethane





Createariskofaccidentalreleasewhichexceedsthe“acceptablewithcontrols”categorythroughtheroutinetransport,use,ordisposalofhazardousmaterials

AcceptableLevelofRisk

Similar(AcceptableLevelofRisk)



Createariskofaccidentalreleasewhichexceedsthe“acceptablewithcontrols”categorythroughreasonablyforeseeableupsetandaccidentconditionsinvolvingthereleaseofhazardousmaterialsintotheenvironment

AcceptableLevelofRisk

Similar(AcceptableLevelofRisk)








Base Remedy


Option





Emithazardousemissionsorhandlehazardousoracutelyhazardousmaterials,substances,orwastewithinone‐quartermileofanexistingorproposedschool






Resultindischargesthatwouldcreatepollution,contaminationornuisanceorcauseregulatorystandardstobeviolated.


Less(PotentiallySignificant)

Similar(LessthanSignificant)

Less(LessThanSignificant)

AffecttherateorchangethedirectionofmovementofexistingCOCsorexpandtheareaaffectedbyCOCs


Greater(PotentiallySignificant)



IncreaselevelofconcentrationsofCOCsingroundwaterorviolateanyfederal,state,orlocalgroundwaterqualitystandard,includingthewaterqualityobjectivesintheBasinPlan


Greater(PotentiallySignificant)








Base Remedy


Option





Noise and Vibration

Resultinexposureofpersonstoorgenerationofnoiselevelsinexcessoflocalstandards;resultinasubstantialpermanentincreaseinambientnoiselevelsintheprojectvicinityaboveexistinglevels;orresultinasubstantialtemporaryorperiodicincreaseinambientnoiselevelsintheprojectvicinityaboveexistinglevels

SignificantandUnavoidable

Similar(SignificantandUnavoidable)

Less(NoImpact) Similar(SignificantandUnavoidable)

Less(SignificantandUnavoidable)

Resultinexposureofpersonsto,orgenerationof,excessivegroundbornevibrationorgroundbornenoiselevels

SignificantandUnavoidable

Similar(SignificantandUnavoidable)

Less(NoImpact) Similar(SignificantandUnavoidable)

Less(SignificantandUnavoidable)


IncreaseintrafficdemandonaCMPfacilityby2percentofcapacity(i.e.,V/Cincreaseof0.02),causingLOSF(V/C>1.00)orifthefacilityisalreadyatLOSFwhentheprojectincreasestrafficdemandonaCMPfacilityby2percentofcapacity(i.e.,V/C









Base Remedy


Option





increaseof0.02).

IncreaseintrafficdemandonaCMPfacilityby2percentofcapacity(i.e.,V/Cincreaseof0.02),causingLOSF(V/C>1.00)orifthefacilityisalreadyatLOSFwhentheprojectincreasestrafficdemandonaCMPfacilityby2percentofcapacity(i.e.,V/Cincreaseof0.02).





Generatesolidwasteinexcessofthepermittedcapacityofthedisposalfacilitiesservingtheproject




Source: PCR Services Corporation, 2014



Table 6‐2

Summary Comparison of the Project’s and Alternatives’ Ability to Meet Project Objectives

ProjectObjective

AbilitytoMeetProjectObjective

RP’sProposedRemedy

Alternative 1 No Project Alternative

Alternative 2

Excavation Beneath Landscape

and Hardscape to

10 Feet Alternative

Alternative 3 No

Excavation Beneath

Hardscape – 5 Feet With Targeted 10

Feet Alternative

1.ImplementaRAPthatcomplieswiththe CAO and meets the media‐specific(i.e. soil, soil vapor, and groundwater)Remedial Action Objectives (RAOs)developed for the site. (See RAO #1throughRAO#4below.)

MeetsObjective

DoesNotMeetObjective

MeetsObjective(BettermeetsObjectivethanproject)

MeetsObjective(Tolesserextentthanproject)

RAO#1.PreventhumanexposurestoconcentrationsofCOCsinsoil,soilvapor,andindoorairsuchthattotal(i.e.,cumulative)lifetimeincrementalcarcinogenicrisksarewithintheNationalOilandHazardousSubstancesPollutionContingencyPlan(NCP)riskrangeof1×10‐6to1×10‐4andnoncancerhazardindicesarelessthan1orconcentrationsarebelowbackground,whicheverishigher.Potentialhumanexposuresincludeon‐siteresidentsandconstructionandutilitymaintenanceworkers.Foron‐siteresidents,thelowerendoftheNCPriskrange(i.e.,1×10‐6)andanoncancerhazardindexlessthan1areused.PreventdirectcontactexposuretoCOCsatconcentrationsaboveapplicablerisk‐basedSSCGsinsoilforon‐siteresidentsandconstructionandutilitymaintenanceworkers.

MeetsObjective




RAO#2.Preventfire/explosionrisksinindoorairand/orenclosedspaces(e.g.,utilityvaults)duetotheaccumulationofmethanegeneratedfromtheanaerobicbiodegradationofpetroleumhydrocarbonsinsoils.Eliminatemethaneinthesubsurfacetotheextenttechnologicallyandeconomicallyfeasible.

MeetsObjective


MeetsObjective

MeetsObjective



Summary Comparison of the Project’s and Alternatives’ Ability to Meet Project Objectives


ProjectObjective

AbilitytoMeetProjectObjective

RP’sProposedRemedy

Alternative 1 No Project Alternative

Alternative 2

Excavation Beneath Landscape

and Hardscape to

10 Feet Alternative

Alternative 3 No

Excavation Beneath

Hardscape – 5 Feet With Targeted 10

Feet Alternative

RAO#3.RemoveortreatLNAPLtotheextenttechnologicallyandeconomicallyfeasible,andwhereasignificantreductionincurrentandfuturethreattogroundwaterwillresult.

MeetsObjective


MeetsObjective

MeetsObjective

RAO#4.ReduceCOCsingroundwatertotheextenttechnologicallyandeconomicallyfeasibletoachieve,ataminimum,SSCGsandthewaterqualityobjectivesintheRegionalBoardBasinPlantoprotectthedesignatedbeneficialuses,includingmunicipalsupply.

MeetsObjective




2.MaintaintheresidentiallanduseofthesiteandavoidpermanentlydisplacingresidentsfromtheirhomesorphysicallydividingtheestablishedCarouselTractcommunity.

MeetsObjective

MeetsObjective

MeetsObjective

MeetsObjective

3.Minimizeshort‐termdisruptiontoresidents.

MeetsObjective

MeetsObjective


MeetsObjective(Bettermeetsobjectivethanproject)

4.Allowresidentsthelong‐termabilitytosafelyandefficientlymakeimprovementsrequiringexcavationorpenetrationintoshallowsitesoils(i.e.,landscaping,hardscape,gardening,etc.)ontheirproperties.

MeetsObjective


MeetsObjective(Bettermeetsobjectivethanproject)


5.Limitorminimizeenvironmentalimpactsassociatedwiththecleanupactivities.

MeetsObjective

MeetsObjective


MeetsObjective(togreaterextentthanproject)

Source:PCRServicesCorporation,2014



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