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Alameda County Community Development Agency Impact Analysis
Noise
APWRA Repowering Draft PEIR 3.11‐1
June 2014ICF 00323.08
3.11 Noise Thissectiondescribestheenvironmentalsettingandregulatorysettingfornoise.Italsodescribesthenoiseimpacts,ifany,thatwouldresultfromimplementationoftheprogramandtwoindividualprojects.Whereapplicable,mitigationmeasuresaredescribedthatwouldreducetheseimpacts.
3.11.1 Existing Conditions
Background Information on Noise
NoiseforthepurposesofenvironmentalanalysisunderCEQAiscommonlydefinedassoundthatannoysordisturbspeopleandpotentiallycausesanadversepsychologicalorphysiologicaleffectonhumanhealth.Becausenoiseisanenvironmentalpollutantthatcaninterferewithhumanactivities,evaluationofnoiseisnecessarywhenconsideringtheenvironmentalimpactsofaproposedproject.
Soundismechanicalenergy(vibration)transmittedbypressurewavesoveramediumsuchasairorwater.Soundischaracterizedbyvariousparametersthatincludetherateofoscillationofsoundwaves(frequency),thespeedofpropagation,andthepressurelevelorenergycontent(amplitude).Inparticular,thesoundpressurelevelisthemostcommondescriptorusedtocharacterizetheloudnessofanambient(existing)soundlevel.Althoughthedecibel(dB)scale,alogarithmicscale,isusedtoquantifysoundintensity,itdoesnotaccuratelydescribehowsoundintensityisperceivedbyhumanhearing.Thehumanearisnotequallysensitivetoallfrequenciesintheentirespectrum,sonoisemeasurementsareweightedmoreheavilyforfrequenciestowhichhumansaresensitiveinaprocesscalledA‐weighting,writtenasdBAandreferredtoasA‐weighteddecibels.Table3.11‐1definessoundmeasurementsandotherterminologyusedinthischapter,andTable3.11‐2summarizestypicalA‐weightedsoundlevelsfordifferentnoisesources.
Ingeneral,humansoundperceptionissuchthatachangeinsoundlevelof1dBcannottypicallybeperceivedbythehumanear,achangeof3dBisbarelynoticeable,achangeof5dBisclearlynoticeable,andachangeof10dBisperceivedasdoublingorhalvingthesoundlevel.
Differenttypesofmeasurementsareusedtocharacterizethetime‐varyingnatureofsound.Thesemeasurementsincludetheequivalentsoundlevel(Leq),theminimumandmaximumsoundlevels(LminandLmax),percentile‐exceededsoundlevels(suchasL10,L20),theday‐nightsoundlevel(Ldn),andthecommunitynoiseequivalentlevel(CNEL).LdnandCNELvaluesdifferbylessthan1dB.Asamatterofpractice,LdnandCNELvaluesareconsideredtobeequivalentandaretreatedassuchinthisassessment.
Forapointsourcesuchasastationarycompressororconstructionequipment,soundattenuatesbasedongeometryatrateof6dBperdoublingofdistance.Foralinesourcesuchasfreeflowingtrafficonafreeway,soundattenuatesatarateof3dBperdoublingofdistance(CaliforniaDepartmentofTransportation2009).Atmosphericconditionsincludingwind,temperaturegradients,andhumiditycanchangehowsoundpropagatesoverdistanceandcanaffectthelevelofsoundreceivedatagivenlocation.Thedegreetowhichthegroundsurfaceabsorbsacousticalenergyalsoaffectssoundpropagation.Soundthattravelsoveranacousticallyabsorptivesurfacesuchasgrassattenuatesatagreaterratethansoundthattravelsoverahardsurfacesuchaspavement.Theincreasedattenuationistypicallyintherangeof1to2dBperdoublingofdistance.
Alameda County Community Development Agency Impact Analysis
Noise
APWRA Repowering Draft PEIR 3.11‐2
June 2014ICF 00323.08
Barrierssuchasbuildingsandtopographythatblockthelineofsightbetweenasourceandreceiveralsoincreasetheattenuationofsoundoverdistance.
Table 3.11‐1. Definition of Sound Measurements
SoundMeasurements Definition
Decibel(dB) Aunitlessmeasureofsoundonalogarithmicscale,whichindicatesthesquaredratioofsoundpressureamplitudetoareferencesoundpressureamplitude.Thereferencepressureis20micro‐pascals.
A‐WeightedDecibel(dBA) Anoverallfrequency‐weightedsoundlevelindecibelsthatapproximatesthefrequencyresponseofthehumanear.
C‐WeightedDecibel(dBC) ThesoundpressurelevelindecibelsasmeasuredusingtheC‐weightingfilternetwork.TheC‐weightingisveryclosetoanunweightedor“flat”response.C‐weightingisonlyusedinspecialcaseswhenlow‐frequencynoiseisofparticularimportance.AcomparisonofmeasuredAandCweightedlevelgivesanindicationoflowfrequencycontent.
MaximumSoundLevel(Lmax) Themaximumsoundlevelmeasuredduringthemeasurementperiod.
MinimumSoundLevel(Lmin) Theminimumsoundlevelmeasuredduringthemeasurementperiod.
EquivalentSoundLevel(Leq) Leqrepresentsanaverageofthesoundenergyoccurringoveraspecifiedperiod.Ineffect,Leqisthesteady‐statesoundlevelcontainingthesameacousticalenergyasthetime‐varyingsoundthatactuallyoccursduringthesameperiod.The1‐hourAweightedequivalentsoundlevel(Leq[h])istheenergyaverageofA‐weightedsoundlevelsoccurringduringa1‐hourperiod.
Percentile‐ExceededSoundLevel(Lxx)
Thesoundlevelexceeded“xx”percentofaspecifictimeperiod.L10isthesoundlevelexceeded10percentofthetime.L90isthesoundlevelexceeded90percentofthetime.L90isoftenconsideredtoberepresentativeofthebackgroundnoiselevelinagivenarea.
Day‐NightLevel(Ldn) TheenergyaverageoftheA‐weightedsoundlevelsoccurringduringa24‐hourperiod,with10dBaddedtotheA‐weightedsoundlevelsoccurringduringtheperiodfrom10:00p.m.to7:00a.m.
CommunityNoiseEquivalentLevel(CNEL)
TheenergyaverageoftheA‐weightedsoundlevelsoccurringduringa24‐hourperiodwith5dBaddedtotheA‐weightedsoundlevelsoccurringduringtheperiodfrom7:00p.m.to10:00p.m.and10dBaddedtotheA‐weightedsoundlevelsoccurringduringtheperiodfrom10:00p.m.to7:00a.m.
PeakParticleVelocity(PeakVelocityorPPV)
Ameasurementofgroundvibrationdefinedasthemaximumspeed(measuredininchespersecond)atwhichaparticleinthegroundismovingrelativetoitsinactivestate.PPVisusuallyexpressedininches/sec.
Frequency:Hertz(Hz) Thenumberofcompletepressurefluctuationspersecondaboveandbelowatmosphericpressure.
Alameda County Community Development Agency Impact Analysis
Noise
APWRA Repowering Draft PEIR 3.11‐3
June 2014ICF 00323.08
Table 3.11‐2. Typical A‐weighted Sound Levels
CommonOutdoorActivitiesNoiseLevel(dBA) CommonIndoorActivities
—110— Rockband
Jetflyoverat1,000feet
—100—
Gaslawnmowerat3feet
—90—
Dieseltruckat50feetat50mph Foodblenderat3feet
—80— Garbagedisposalat3feet
Noisyurbanarea,daytime
Gaslawnmower,100feet —70— Vacuumcleanerat10feet
Commercialarea Normalspeechat3feet
Heavytrafficat300feet —60—
Largebusinessoffice
Quieturbandaytime —50— Dishwasherinnextroom
Quieturbannighttime —40— Theater,largeconferenceroom(background)
Quietsuburbannighttime
—30— Library
Quietruralnighttime Bedroomatnight,concerthall(background)
—20—
Broadcast/recordingstudio
—10—
—0—
Source:CaliforniaDepartmentofTransportation2009.
Other Factors Related to Wind Turbines
Operatingwindturbinescangeneratetwotypesofsound:mechanicalsoundfromcomponentssuchasgearboxes,generators,yawdrives,andcoolingfans;andaerodynamicsoundfromtheflowofairoverandpasttherotorblades.Modernwindturbinedesignhasgreatlyreducedmechanicalsound,whichisgenerallyunnoticeableincomparisonwiththeaerodynamicsound,whichisoftendescribedasa“swishing”or“whooshing”sound.TheInternationalStandardIEC61400‐11forwindturbinenoiseassessmentprovidesarequirementforevaluatingtonality.Tonesarethendividedintocategoriesofprominenttone,audibletone,ornotone.(Illingworth&Rodkin2006.)
Comparedwithother,primarilyolderwindturbines,themodernwindturbinesthatwouldbeinstalledthroughtherepoweringprogramhaveseveralcharacteristicsthatreduceaerodynamicsoundlevels.Themodernturbinestypicallyareupwindturbines,meaningeachturbinefacesintothewind,sothewindencounterstherotorbladesbeforethetowerandnacelle,makingforquieteroperationsthanadownwindturbine.Additionally,themodernturbineshaverelativelylowrotationalspeedsandpitchcontrolontherotors,bothofwhichreducesoundlevels.
Alameda County Community Development Agency Impact Analysis
Noise
APWRA Repowering Draft PEIR 3.11‐4
June 2014ICF 00323.08
Windturbinesproduceabroadbandsound(i.e.,thesoundoccursoverawiderangeoffrequencies,includinglowfrequencies).Low‐frequencysoundsareintherangeof20–100Hz,andinfrasonicsound(orinfrasound)islow‐frequencysoundoflessthan20hertz.Comparedwithhigherfrequencysound,low‐frequencysoundpropagatesoverlongerdistances,istransmittedthroughbuildingsmorereadily,andcanexcitestructuralvibrations(e.g.,rattlingwindowsordoors).Thethresholdofperception,indecibels,alsoincreasesasthefrequencydecreases.Forexample,inthefrequencyrangewherehumanshearbest(inthelowkilohertz),thethresholdofhearingisatabout0dB,butatafrequencyofonly10Hz,thethresholdofhearingisatabout100dB(Rogersetal.2006a).
Olderwindturbines—particularlythoseinwhichthebladeswereonthedownwindsideofthetower—producedmorelow‐frequencysoundbecausetheirtowersblockedwindflow,causingthebladestopassthroughmoreturbulentair.Modern,upwindturbinesproduceabroadbandsoundthatincludeslow‐frequencysounds,butnotatsignificantlevels.Aprimarycauseforlow‐frequencysoundsinmodernturbinesisthebladepassingthroughthechangeinairflowatthefrontofthetower,andthiscanbeaggravatedbyunusuallyturbulentwindconditions.Thiseffectisgenerallyreferredtoasbladeamplitudemodulationbecausetheaerodynamicnoisegeneratedbytheblades(the“swishing”sound)ismodulatedastheturbinebladespassthroughunevenairvelocities.Theunevenairthatcausesthiseffectmaybeduetointeractionofotherturbines,excessivewindshear,ortopography(Bowdler2008).
TheUniversityofMassachusettsatAmherstreportedonnoisemeasurementsmadeatfourdifferentwindturbinesrangingfrom450kilowattsto2megawatts(Rogersetal.2006b).Theresultsindicatedthatatdistancesofnomorethan118meters(387feet)fromtheturbines,allinfrasoundlevelswerebelowhumanperceptionlevels.Thereportfurtherstatesthatthereis“noreliableevidencethatinfrasoundbelowthehearingthresholdproducesphysiologicalorpsychologicaleffects.”Thislackofeffectsatlevelsbelowthehearingthresholdwassupportedbyascientificadvisorypanelcomposedofmedicaldoctors,audiologists,andacousticalprofessionalsestablishedbytheAmericanandCanadianWindEnergyAssociationstoreviewwindturbinesoundandhealtheffects(Colbyetal.2009).ItwasalsosupportedbyCanadianandAustraliangovernmentreviewsofavailablescientificliterature(AustraliaNationalHealthandMedicalResearchCouncil2010;OntarioChiefMedicalOfficerofHealth2010).
Additionalrecentstudiesconductedona2.3MWSiemensSWT‐2.3‐93turbine(O’Nealetal.2010)areausefulpointofreferencewiththeregardtolowfrequencynoisegeneratedbyamodernwindturbinegenerator.ThesestudiesconcludedthattheSiemensSWT‐2.3‐93windturbineatmaximumnoiseatadistanceofabout305meters(1,000feet)fromthenearestresidencedoesnotposealowfrequencynoiseorinfrasoundproblem.Atthisdistancetheturbinesatisfiesthefollowingobjectives.
MeetsAmericanNationalStandardsInstitute/AmericanStandardsAssociation[ANSI/ASA]S12.2indoorlevelsforlowfrequencysoundforbedrooms,classrooms,andhospitals.
MeetsANSI/ASAS12.2indoorlevelsformoderatelyperceptiblevibrationsinlightweightwallsandceilings.
MeetsANSIS12.9Part4thresholdsforannoyanceandbeginningofrattles.
Producesnoaudibleinfrasoundcapableofdetectionbythemostsensitivelisteners.
Windgeneratessoundwhenitinteractswithstructuresandvegetationontheground.Theamountofsoundgeneratedcanvarywidelydependingprimarilyontheamountofvegetationinthearea
Alameda County Community Development Agency Impact Analysis
Noise
APWRA Repowering Draft PEIR 3.11‐5
June 2014ICF 00323.08
andthespeedofthewind.Foragivenwindspeed,thesoundlevelinadesertwithnotreesorvegetationwillbedifferentthaninahighlyvegetatedarea.Whentreesareinfullleaf,windinthetreesrustlestheleavesandhighfrequencysoundisproduced(HooverandKeith2000).Theamountofsoundgenerateddependsonwindspeed,thedistancefromtheobservedpositiontothetreesorfoliage,andtheapproximatefrontalareaofthetreesorfoliageasseenfromtheobservedposition.Soundlevelsgeneratedbywindcanrangefromabout20dBAto60dBAforwindspeedsintherangeof2to20milesperhour(HooverandKeith2000).
Regulatory Setting
Federal
Federal,state,andlocalagenciesregulatedifferentaspectsofenvironmentalnoise.Generally,thefederalgovernmentsetsnoisestandardsfortransportation‐relatednoisesourcescloselylinkedtointerstatecommerce.Theseincludeaircraft,locomotives,andtrucks.Thestategovernmentsetsnoisestandardsfortransportationnoisesourcessuchasautomobiles,lighttrucks,andmotorcycles.Noisesourcesassociatedwithindustrial,commercial,andconstructionactivitiesaregenerallysubjecttolocalcontrolthroughnoiseordinancesandgeneralplanpolicies.Localgeneralplansidentifygeneralprinciplesintendedtoguideandinfluencedevelopmentplans.
State
Part2,Title24oftheCaliforniaCodeofRegulations“CaliforniaNoiseInsulationStandards”establishesminimumnoiseinsulationstandardstoprotectpersonswithinnewhotels,motels,dormitories,long‐termcarefacilities,apartmenthouses,anddwellingsotherthansingle‐familyresidences.Underthisregulation,interiornoiselevelsattributabletoexteriornoisesourcescannotexceed45Ldninanyhabitableroom.Wheresuchresidencesarelocatedinanenvironmentwhereexteriornoiseis60Ldnorgreater,anacousticalanalysisisrequiredtoensurethatinteriorlevelsdonotexceedthe45Ldninteriorstandard.
TheStateofCaliforniaGeneralPlanGuidelines(Governor’sOfficeofPlanningandResearch2003)identifiesguidelinesforthenoiseelementsoflocalgeneralplans,includingasoundlevel/landusecompatibilitychartthatcategorizes,bylanduse,outdoorLdnrangesinuptofourcategories(normallyacceptable,conditionallyacceptable,normallyunacceptable,andclearlyunacceptable).Formanylanduses,thechartshowsoverlappingLdnrangesfortwoormorecompatibilitycategories.
ThenoiseelementguidelinechartidentifiesthenormallyacceptablerangeofLdnvaluesforlow‐densityresidentialusesaslessthan60dBandtheconditionallyacceptablerangeas55–70dB.Thenormallyacceptablerangeforhigh‐densityresidentialusesisidentifiedasLdnvaluesoflessthan65dB,andtheconditionallyacceptablerangeisidentifiedas60–70dB.Foreducationalandmedicalfacilities,Ldnvaluesoflessthan70dBareconsiderednormallyacceptable,andLdnvaluesof60–70dBareconsideredconditionallyacceptable.Forofficeandcommerciallanduses,Ldnvaluesoflessthan70dBareconsiderednormallyacceptable,andLdnvaluesof67.5–77.5arecategorizedasconditionallyacceptable.Whennoiselevelsareintheconditionallyacceptablerangenewconstructionshouldbeundertakenonlyafteradetailedanalysisofthenoisereductionrequirementsismadeandneedednoiseinsulationrequirementsareincludedinthedesign.
Alameda County Community Development Agency Impact Analysis
Noise
APWRA Repowering Draft PEIR 3.11‐6
June 2014ICF 00323.08
TheseoverlappingLdnrangesareintendedtoindicatethatlocalconditions(existingsoundlevelsandcommunityattitudestowarddominantsoundsources)shouldbeconsideredinevaluatinglandusecompatibilityatspecificlocations.
Local
General Plan Noise Element
TheAlamedaCountyGeneralPlanNoiseElement(AlamedaCounty1976)containsgoals,objectives,andimplementationprogramsfortheentirecountytoprovideitsresidentswithanenvironmentthatisfreefromexcessivenoiseandthatpromotescompatibilityoflanduseswithrespecttonoise.TheCountywideNoiseElementdoesnotexplicitlydefinetheacceptableoutdoornoiselevelforthebackyardsofsingle‐familyhomesorcommonoutdoorspacesofmulti‐familyhousingprojects,butitrecognizestheFederalEnvironmentalProtectionAgency(EPA)noiselevelstandardsforresidentiallanduses.ThesestandardsareanexteriorLdnof55dBAandaninteriorLdnof45dBA.(TheLdnmeasurement,whichalsoincludesa10dBweightingfornight‐timesound,isapproximatelyequaltotheCNELformostenvironmentalsettings.)TheNoiseElementalsoreferencesnoiseandlandusecompatibilitystandardsdevelopedbyanAssociationofBayAreaGovernments(ABAG)‐sponsoredstudy.
East County Area Plan
AlamedaCounty’sECAP(AlamedaCounty2000)containsthefollowinggoal,policiesandimplementationprogramsrelatedtocommunitynoiseandwindfarms.
Goal:TominimizeEastCountyresidents’andworkers’exposuretoexcessivenoise.
Policies
Policy170:TheCountyshallprotectnearbyexistingusesfrompotentialtraffic,noise,dust,visual,andotherimpactsgeneratedbytheconstructionandoperationofwindfarmfacilities.
Policy288:TheCountyshallendeavortomaintainacceptablenoiselevelsthroughoutEastCounty.
Policy289:TheCountyshalllimitorappropriatelymitigatenewnoisesensitivedevelopmentinareasexposedtoprojectednoiselevelsexceeding60dBbasedontheCaliforniaOfficeofNoiseControlLandUseCompatibilityGuidelines.
Policy290:TheCountyshallrequirenoisestudiesaspartofdevelopmentreviewforprojectslocatedinareasexposedtohighnoiselevelsandinareasadjacenttoexistingresidentialorothersensitivelanduses.Wherenoisestudiesshowthatnoiselevelsinareasofexistinghousingwillexceed“normallyacceptable”standards(asdefinedbytheCaliforniaOfficeofNoiseControlLandUseCompatibilityGuidelines),majordevelopmentprojectsshallcontributetheirpro‐ratedsharetothecostofnoisemitigationmeasuressuchasthosedescribedinProgram104.
ImplementationPrograms
Program74:TheCountyshallamendtheZoningOrdinancetoincorporatesitinganddesignstandardsforwindturbinestomitigatebiological,visual,noise,andotherimpactsgeneratedbywindfarmoperations.
Program104:TheCountyshallrequiretheuseofnoisereductiontechniques(suchasbuffers,buildingdesignmodifications,lotorientation,soundwalls,earthberms,landscaping,buildingsetbacks,andrealestatedisclosurenotices)tomitigatenoiseimpactsgeneratedbytransportation‐relatedandstationarysourcesasspecifiedintheCaliforniaOfficeofNoiseControlLandUseCompatibilityGuidelines.
Alameda County Community Development Agency Impact Analysis
Noise
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June 2014ICF 00323.08
Noise Ordinance
AlamedaCounty’snoiseordinance(CountyGeneralCode,Chapter6.60)allowshighernoiseexposurelevelsforcommercialpropertiesthanforresidentialuses,schools,hospitals,churches,orlibraries.Thesestandardsaugmentthestate‐mandatedrequirementsoftheAlamedaCountyBuildingCode,whichestablishesstandardsforinteriornoiselevelsconsistentwiththenoiseinsulationstandardsintheCaliforniaStateBuildingCode.Table3.11‐3showsthenumberofcumulativeminutesthataparticularexternalnoiselevelispermitted,aswellasthemaximumnoiseallowedundertheAlamedaCountyGeneralCode.
Table 3.11‐3. Alameda County Exterior Noise Standards
CumulativeNumberofMinutesinAny1‐HourTimePeriodDaytime
Daytime(7a.m.to10p.m.)
Nighttime(10p.m.to7a.m.)
Residentialuses,schools,hospitals,churches,andlibraries
30 50dBA 45dBA
15 55dBA 50dBA
5 60dBA 55dBA
1 65dBA 60dBA
Maximum 70dBA 65dBA
Commercialuses
30 65dBA 60dBA
15 70dBA 65dBA
5 75dBA 70dBA
1 80dBA 75dBA
Maximum 85dBA 80dBA
Source:AlamedaCountyGeneralCode,Chapter6.60.
TheCountyZoningOrdinance(CountyGeneralCode,Chapter17)restrictsnoisefromcommercialactivitiesbyprohibitinganyusethatwouldgenerateanoiseorvibrationthatisdiscerniblewithoutinstrumentsbeyondthepropertyline.Thisperformancestandarddoesnotapplytotransportationactivitiesortemporaryconstructionwork.
Theprovisionsoftheordinancedonotapplytonoisesourcesassociatedwithconstruction,providedtheactivitiesdonottakeplacebefore7a.m.orafter7p.m.onanydayexceptSaturdayorSunday,orbefore8a.m.orafter5p.m.onSaturdayorSunday.
Conditional Use Permits
TheCounty’sCUPsforthecontinuedoperationofthewindfarmsafter2005,regulatedbyResolutionNumberR‐2005‐463,identifiedthefollowingspecificconditionregardingnoiselevels.
NoiseStandards:WindturbinesshallbeoperatedsoastonotexceedtheCounty’snoisestandardof55dBA(Ldn)or70dBC(Ldn)asmeasuredinbothcasesattheexteriorofanydwellingunit.IfthedwellingunitisonlandunderleasefromthePermittee,theapplicablestandardshallbe65dBA(Ldn)and70dBC(Ldn).
TheResolutionapprovingtheCUPsforwindfarmoperationsincludedafindingthatasalanduse,thewindenergyuse“isproperlyrelatedtootherlandusesandtransportationandservicefacilities
Alameda County Community Development Agency Impact Analysis
Noise
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June 2014ICF 00323.08
inthevicinity,inthat…d)Althoughsomeresidentsmayobjecttothevisual,noise,orothereffectsoftheturbines,theCountyhasdeterminedthatthewindenergyprojectsareincompliancewiththeconditionsofapprovalandareanacceptableuseinthearea.”
Environmental Setting
Existing Land Uses
TheprogramareaistheAlamedaCountyportionoftheHCP‐revisedAPWRA.TheareaisdesignatedasLargeParcelAgricultureundertheCountyZoningOrdinanceandtheECAP.Generalagriculture,single‐familyresidences,grazing,andridingorhikingtrailsarealloweduses.ConditionalusesthatmaybeallowedthroughaCUPgrantedbytheCountyincludeoutdoorrecreationfacilities,transmissionfacilities,solidwastelandfills,andwindfarms.CUPsaredevelopedtobeconsistentwithgeneralplanpoliciesandotherlandusespermittedbytheCounty’sgeneralplan.
Program Area
Scatteredsingle‐familyruralresidencesarelocatedwithintheprogramboundary,includinghomesonbothverylargeparcels(morethan100acres)andcomparativelysmalllots(lessthan5acres).Single‐familyruralresidencesaremostlylocatedalongthewestandnortheastsidesoftheprogramarea.Withintheprogramboundary,severalresidencesalongAltamontPassRoadarelocatedascloseasabout600feetfromexistingturbines.TworesidencesalongFlynnRoadarelocatedabout800feetfromexistingturbines.SeveralresidenceslocatedalongDyerRoadarewithinabout1,100feetofexistingturbines.Nootherresidencesarelocatedwithin1,500feetoftheexistingturbinesintheprogramboundary.
Golden Hill Project Area
TworesidenceslocatedalongFlynnRoadareabout800feetfromthenearestturbineswithintheprojectboundary.Nootherresidencesarelocatedwithin1,500feetoftheexistingturbineswithintheprojectboundary.
Patterson Pass Project Area
TheclosestresidenceislocatedoffPattersonPassRoadabout2,200feetawayofthenearestturbineswithintheprojectboundary.
Existing Noise Conditions
TrafficonI‐580andwindturbineoperationsarethepredominantsourcesofnoiseintheprogramarea.Basedontrafficnoiseprojectionsfor2010,the60LdncontourfortraffictravelingonI‐580extendsabout1,800feetfromthefreeway(AlamedaCounty2000).
ThefollowingisasummaryofambientnoisemeasurementsconductedatsevenpositionsintheAltamontPassareaonMay17,2013(ICFInternational2013).Thesemeasurementsaregenerallyrepresentativeofnoiselevelsintheprogramareawherefirstgenerationwindturbinesarecurrentlyoperating.
PositionM1.AltamontPassRoad1.2mileswestofWestGrantLineRoad.300feetfromthenearestoperatingturbine.
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PositionM2.AltamontPassRoad1.1mileswestofWestGrantLineRoad.380feetfromthenearestoperatingturbine.
PositionM3.AltamontPassRoad0.7mileswestofWestGrantLineRoad.750feetfromthenearestoperatingturbine.
PositionM4.MountainHouseRoad.1.4milesnorthofWestGrantLineRoad.590feetfromthenearestoperatingturbine.
PositionM5.MountainHouseRoad.500feetnorthofWestGrantLineRoad.1,200feetfromthenearestoperatingturbine.
PositionM6.NorthMidwayRoad.0.9milessouthofI‐205.315feetfromthenearestoperatingturbine.
PositionM7.NorthMidwayRoad.0.6milessouthofI‐205.1,710feetfromthenearestoperatingturbine.
Table 3.11‐4. Summary of Noise Measurements in the APWRA
Position StartTime Duration Leq Lmax Lmin L10 L33 L50 L90
M1 10:17a.m. 5min 58.4 67.9 54.7 60.4 58.3 57.5 55.9
M2 10:38a.m. 5min 56.1 62.6 53.6 57.6 56.0 55.5 54.3
M3 10:38a.m. 5min 53.3 67.2 49.1 54.5 62.9 52.3 50.5
M4 11:24a.m. 5min 56.7 73.6 51.2 57.4 56.1 55.6 53.8
M5 11:43a.m. 5min 47.0 60.3 40.8 50.0 46.6 45.6 43.1
M6 12:18p.m. 5min 50.0 55.0 44.6 52.1 50.5 49.6 47.1
M7 12:36p.m. 5min 56.8 65.4 50.9 59.1 56.9 55.6 52.6
Althoughsoundfromexistingoperatingturbinesisaudibleadjacenttothem,thereisnodocumentedevidencethatnoisestandardsoftheexistingCUPs,asdefinedaboveintheConditionalUsePermitssection,havebeenexceeded.
3.11.2 Environmental Impacts
ThissectiondescribestheimpactanalysisrelatingtonoisefortheproposedprogramandtheGoldenHillsandPattersonPassprojects.Itdescribesthemethodsusedtodeterminetheimpactsoftheprogramandprojectsandliststhethresholdsusedtoconcludewhetheranimpactwouldbesignificant.Measurestomitigate(i.e.,avoid,minimize,rectify,reduce,eliminate,orcompensatefor)significantimpactsaccompanytheimpactdiscussion.
Methods for Analysis
Wind Turbine Noise
Theproposedprogramwouldreplacetheexistingturbines(first‐andsecond‐generationturbines)withfewerandlargercurrent‐generationturbines.Section2.3ofthisProgramEIR,WindTurbineTechnology,providesadescriptionandcomparisonofexistingandproposedturbines.Thespecifictypesorsounddataofcurrentgenerationwindturbinestobeusedintheprogramareaarenotknownand,therefore,thelevelsofnoiseproducedbytheinstallationofnewturbinescannotbe
Alameda County Community Development Agency Impact Analysis
Noise
APWRA Repowering Draft PEIR 3.11‐10
June 2014ICF 00323.08
specificallydetermined.However,noiseproducedbycurrentgenerationturbinessuchastheREpowerMM92turbineandtheVestasV90turbineareknowntoproduceasoundlevelofabout44dBAat1,000feet(SolanoCounty2011).Continuousoperationovera24‐hourperiodwouldresultinabout50dBA(Ldn)at1,000feet.Atanygivenreceptorlocation,thereceivednoiselevelfromturbineoperationcouldbepotentiallyinfluencedbyseveralturbines,dependingonthegeometricrelationshipbetweentheturbinesandthereceptor.Table3.11‐5providesanindicationofpotentialreceivednoiselevelsexpressedindBA(Ldn)basedonthedistancetoareceiverandthenumberofturbinesinfluencingnoisereceivedatthereceptor.Thetablealsohighlights(usingshading)thedistanceswithinwhichtheCountystandardof55dBA(Ldn)wouldbeexceeded.Undertheassumptionthatupto10turbinescouldaffectthereceivednoiselevelatareceptor,theresultsinTable3.11‐5indicatethattheCountynoisestandardof55dBA(Ldn)couldbeexceededwithinabout1,750feetofareceptor.
Table 3.11‐5. Turbine Noise Level, dBA (Ldn), as a Function of Distance and Number of Turbines
Distance(feet)
NumberofTurbinesInfluencingtheReceivedNoiseLevel
1 2 3 4 5 7 10
500 56 59 61 62 63 64 66
550 55 58 60 61 62 63 65
750 52 55 57 58 59 60 62
1,000 50 53 55 56 57 58 60
1,150 49 52 54 55 56 57 59
1,250 48 51 53 54 55 56 58
1,400 47 50 52 53 54 55 57
1,500 46 49 51 52 53 54 56
1,750 45 48 50 51 52 53 55
2,000 44 47 49 50 51 52 54
2,500 42 45 47 48 49 50 52
3,000 40 43 45 46 47 48 50
Note:Basedonsimplegeometricattenuationof6dBperdoublingofdistance.
C‐weightedsoundlevelsprovideameasureoflowfrequencysoundenergyassociatedwithoperationofawindturbine.C‐weightedsoundlevelsfortheREpowerMM92turbineandtheVestasV90areabout10dBhigherthanA‐weightedsoundlevels.TheC‐weightedcountystandardforwindturbinesis70dBC(Ldn).
Table3.11‐6providesanindicationofpotentialreceivednoiselevelsexpressedindBC(Ldn)basedonthedistancetoareceiverandthenumberofturbinesinfluencingnoisereceivedatthereceptor.ThetablealsohighlightsdistanceswithinwhichtheCountystandardof70dBC(Ldn)wouldbeexceeded.Undertheassumptionthatupto10turbinescouldaffectthereceivednoiselevelatareceptor,theresultsinTable3.11‐6indicatethattheCountynoisestandardof70dBC(Ldn)couldbeexceededwithinabout1,000feetofareceptor.
Alameda County Community Development Agency Impact Analysis
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Table 3.11‐6. Turbine Noise Level, dBC (Ldn), as a Function of Distance and Number of Turbines
Distance(feet)
NumberofTurbinesInfluencingtheReceivedNoiseLevel
1 2 3 4 5 7 10
500 66 69 71 72 73 74 76
550 65 68 70 71 72 73 75
650 64 67 69 70 71 72 74
700 63 66 68 69 70 71 73
800 62 65 67 68 69 70 72
1,000 60 63 65 66 67 68 70
2,500 52 55 57 58 59 60 62
3,000 50 53 55 56 57 58 60
Construction Noise
Constructionactivitieswouldinvolvetheuseofheavyequipment.Toassessnoiseimpactsassociatedwiththeseactivities,constructionequipmentisidentifiedandnoiseisevaluatedusingmethodsrecommendedbytheFederalHighwayAdministration(FederalHighwayAdministration2006).NoiseimpactsassociatedwithincreasedconstructiontrafficisevaluatedusingmethodsfortheFHWAtrafficnoisemodel(TNM).
TheCountyusesanoisestandardforwindturbinesintheprogramareaof55dBA(Ldn)or70dBC(Ldn)atdwellingunits,withtheexceptionthatdwellingunitsonthesameparcelbeingleasedforwindfarmusemaybeexposedtoupto65dBA(Ldn).Noiseimpactsassociatedwiththeproposedprogramareevaluatedbasedonhowtheprojectwouldchangethedailynoiselevelassociatedwithwindturbineoperations.Thethresholdof5dBisusedbecauseitisgenerallyconsideredtobethelowestsoundlevelchangeclearlynoticeablebythehumanear.
Determination of Significance
InaccordancewithAppendixGoftheStateCEQAGuidelinesandtheCountyconditionsofapprovalfortheexistingturbineoperations,programAlternative1,programAlternative2,theGoldenHillsproject,orthePattersonPassprojectwouldbeconsideredtohaveasignificanteffectifitwouldresultinanyoftheconditionslistedbelow.
Exposureofresidencestonoisefromnewwindturbinesinexcessof55dBA(Ldn)wherewindturbinenoiseiscurrentlylessthan55dBA(Ldn).Inthesituationwherethedwellingunitisonthesameparcelbeingleasedforwindfarm,65dBA(Ldn)isusedasthethreshold.
Exposureofresidencestonoisefromnewwindturbinesinexcessof70dBC(Ldn)wherewindturbinenoiseiscurrentlylessthan70dBC(Ldn).
ExposureofresidencestoadailynoiseincreaseinLdnvalueofmorethan5dBfromtheadditionofnewwindturbineswheretheexistingnoiselevelisinexcessof55dBA(Ldn).Inthesituationwherethedwellingunitisonthesameparcelbeingleasedforwindfarm,65dBA(Ldn)isusedasthethreshold.
Alameda County Community Development Agency Impact Analysis
Noise
APWRA Repowering Draft PEIR 3.11‐12
June 2014ICF 00323.08
ExposureofresidencestoequipmentnoiseassociatedwithconstructionactivitiesthatexceedAlamedaCountynoiseordinancestandards(Table3.11‐3)duringnonexempthours(7p.m.to7a.m.onweekdaysand5p.m.to8a.m.onSaturdayandSunday).
Impacts and Mitigation Measures
ImpactNOI‐1a‐1:Exposureofresidencestonoisefromnewwindturbines—programAlternative1:417MW(lessthansignificantwithmitigation)
ProgramAlternative1wouldreplacetheexistingturbines(first‐andsecond‐generationturbines)withfewerandlargercurrent‐generationturbines.Thelocationandtypesofturbinestobeusedwouldbedeterminedasprojectsareproposed.Section2.5.2discussesCountysitingrequirementsandtechnicalsitingrequirementsfortheproposedturbines;updatedsetbackrequirementsarepresentedinTable2‐2.
Asdiscussedabove,therearenodocumentedinstancesofwindturbinescausingexceedanceofnoisestandardsintheexistingCUPs.Inaddition,current‐generationturbinesexpectedtobeinstalledthroughtherepoweringprogramhaveseveralcharacteristicsthatreduceaerodynamicsoundlevels.Themodernturbinestypicallyareupwindturbines,meaningeachturbinefacesintothewind,sothewindencounterstherotorbladesbeforethetowerandnacelle,makingforquieteroperationsthanadownwindturbine.Additionally,themodernturbineshaverelativelylowrotationalspeedsandpitchcontrolontherotors,bothofwhichreducesoundlevels.
ThenoisepredictionresultsinTable3.11‐5,however,indicatethatresidenceslocatedwithinabout1,500feetofagroupofturbinescouldbeexposedtonoisethatexceeds55dBA(Ldn).ThenoisepredictionresultsinTable3.11‐6alsoindicatesthatresidenceslocatedwithinabout800feetofagroupofturbinescouldbeexposedtonoisethatexceeds70dBC(Ldn).BecauseofthepossibilitythatimplementationofprogramAlternative1couldresultindailyLdnvaluescausedbywindturbinestoincreasebymorethan5dBatlocationswherenoisecurrentlyexceeds55dBA(Ldn),exposeresidencestonoiseinexcessof55dBA(Ldn)wherenoiseiscurrentlylessthan55dBA(Ldn),orexposeresidencetonoiseinexcessof70dBC(Ldn)thisimpactisconsideredtobesignificant.ImplementationofMitigationMeasureNOI‐1wouldreducethisimpacttoaless‐than‐significantlevel.
MitigationMeasureNOI‐1:Performproject‐specificnoisestudiesandimplementmeasurestocomplywithCountynoisestandards
Theapplicantforanyproposedrepoweringprojectwillretainaqualifiedacousticconsultanttoprepareareportthatevaluatesnoiseimpactsassociatedwithoperationoftheproposedwindturbines.Thisevaluationwillincludeanoisemonitoringsurveytoquantifyexistingnoiseconditionsatnoisesensitivereceptorslocatedwithin2,000feetofanyproposedturbinelocation.ThissurveywillincludemeasurementofthedailyA‐weightedandC‐weighedLdnvaluesovera1‐weekperiodandconcurrentloggingofwindspeedsatthenearestmeteorologicalstation.Thestudywillincludeasite‐specificevaluationofpredictedoperationalnoiselevelsatnearbynoisesensitiveuses.Ifoperationoftheprojectispredictedtoresultinnoiseinexcessof55dBA(Ldn)wherenoiseiscurrentlylessthan55dBA(Ldn),resultina5dBincreasewherenoiseiscurrentlygreaterthan55dBA(Ldn),orresultinnoisethatexceeds70dBC(Ldn),theapplicantwillmodifytheproject,includingselectingnewspecificinstallationsiteswithintheprogramarea,toensurethattheseperformancestandardswillnotbeexceeded.
Alameda County Community Development Agency Impact Analysis
Noise
APWRA Repowering Draft PEIR 3.11‐13
June 2014ICF 00323.08
Methodsthatcanbeusedtoensurecompliancewiththeseperformancestandardsincludeincreasingthedistancebetweenproposedturbinesandnoisesensitiveusesandtheuseofalternativeturbineoperationalmodestoreducenoise.Uponcompletionoftheevaluation,theprojectapplicantwillsubmitareporttotheCountydemonstratinghowtheprojectwillcomplywiththeseperformancestandards.AfterreviewandapprovalofthereportbyCountystaff,theapplicantwillincorporatemeasuresasnecessaryintotheprojecttoensurecompliancewiththeseperformancestandards.
ImpactNOI‐1a‐2:Exposureofresidencestonoisefromnewwindturbines—programAlternative2:450MW(lessthansignificantwithmitigation)
ProgramAlternative2wouldreplacetheexistingturbines(first‐andsecond‐generationturbines)withfewerandlargercurrent‐generationturbines.Thelocationandtypesofturbinestobeusedwouldbedeterminedasprojectsareproposed.Section2.5.2discussesCountysitingrequirementsandtechnicalsitingrequirementsfortheproposedturbines;updatedsetbackrequirementsarepresentedinTable2‐2.
Asdiscussedabove,therearenodocumentedinstancesofwindturbinescausingexceedanceofnoisestandardsintheexistingCUPs.Inaddition,current‐generationturbinesexpectedtobeinstalledthroughtherepoweringprogramhaveseveralcharacteristicsthatreduceaerodynamicsoundlevels.Themodernturbinestypicallyareupwindturbines,meaningeachturbinefacesintothewind,sothewindencounterstherotorbladesbeforethetowerandnacelle,makingforquieteroperationsthanadownwindturbine.Additionally,themodernturbineshaverelativelylowrotationalspeedsandpitchcontrolontherotors,bothofwhichreducesoundlevels.
ThenoisepredictionresultsinTable3.11‐5,however,indicatethatresidenceslocatedwithinabout1,500feetofagroupofturbinescouldbeexposedtonoisethatexceeds55dBA(Ldn).ThenoisepredictionresultsinTable3.11‐6alsoindicatesthatresidenceslocatedwithinabout800feetofagroupofturbinescouldbeexposedtonoisethatexceeds70dBC(Ldn).BecauseofthepossibilitythatimplementationofprogramAlternative2couldresultindailyLdnvaluescausedbywindturbinestoincreasebymorethan5dBatlocationswherenoisecurrentlyexceeds55dBA(Ldn),exposeresidencestonoiseinexcessof55dBA(Ldn)wherenoiseiscurrentlylessthan55dBA(Ldn),orexposeresidencetonoiseinexcessof70dBC(Ldn)thisimpactisconsideredtobesignificant.ImplementationofMitigationMeasureNOI‐1wouldreducethisimpacttoaless‐than‐significantlevel.
MitigationMeasureNOI‐1:Performproject‐specificnoisestudiesandimplementmeasurestocomplywithCountynoisestandards
ImpactNOI‐1b:Exposureofresidencestonoisefromnewwindturbines—GoldenHillsProject(lessthansignificantwithmitigation)
Theprojectwouldremovethemajorityoftheexistingturbines(about734turbines)intheprojectareaandinstall27to48larger,current‐generationturbines.Thespecificsounddataforturbinestobeusedintheprojectareaarenotknown.Figure2‐15showsthelayoutofproposedturbinesintheprojectarea.Thenewturbineswouldbeinstalledfartherfromexistingresidencesthantheexistingturbines.TworesidenceslocatedalongFlynnRoadthatareabout800feetfromtheexistingturbineswouldbeabout1,300to1,800feetfromproposedturbines.
Alameda County Community Development Agency Impact Analysis
Noise
APWRA Repowering Draft PEIR 3.11‐14
June 2014ICF 00323.08
AsdiscussedunderImpactNOI‐1a,therearenodocumentedinstancesofwindturbinescausingexceedanceofnoisestandardsintheexistingCUPs.Inaddition,proposedmodernturbineshaveseveralcharacteristicsthatreduceaerodynamicsoundlevelsandmakeforquieteroperationsthantheexistingturbines.Themodernturbineshaverelativelylowrotationalspeedsandpitchcontrolontherotors,bothofwhichreducesoundlevels.
ThenoisepredictionresultsinTable3.11‐5however,indicatethatresidenceslocatedwithinabout1,500feetofagroupofturbinescouldbeexposedtonoisethatexceeds55dBA(Ldn)orincreasesinnoisegreaterthan5dB.ThenoisepredictionresultsinTable3.11‐6alsoindicatethatresidenceslocatedwithinabout800feetofagroupofturbinescouldbeexposedtonoisethatexceeds70dBC(Ldn).Nonewturbinesareanticipatedtobelocatedwithin1,000feetofexistingresidences.BecauseofthepossibilitythatdailyLdnvaluecausedbywindturbinescouldincreasebymorethan5dBatlocationswherenoisecurrentlyexceeds55dBA(Ldn),exposeresidencestonoiseinexcessof55dBA(Ldn)wherenoiseiscurrentlylessthan55dBA(Ldn),orexposeresidencestonoiseinexcessof70dBC(Ldn)thisimpactisconsideredtobesignificant.ImplementationofMitigationMeasureNOI‐1,asdiscussedunderImpactNOI‐1a,wouldreducethisimpacttoaless‐than‐significantlevel.
MitigationMeasureNOI‐1:Performproject‐specificnoisestudiesandimplementmeasurestocomplywithCountynoisestandards
ImpactNOI‐1c:Exposureofresidencestonoisefromnewwindturbines—PattersonPassProject(lessthansignificant)
Implementationoftheprojectwouldremovetheexistingturbines(about317turbines)intheprojectareaandinstall8to12larger,current‐generationturbines.Figure2‐17showsthelayoutofproposedturbinesintheprojectarea.Thespecifictypeofturbinetobeusedandturbine‐specificnoiselevelshavenotyetbeendetermined.Thenewturbineswouldbeinstalledfartherawayfromtheexistingresidence.OneresidencelocatedoffPattersonPassRoadiscurrentlylocatedabout2,200feetfromtheexistingturbinesandwouldbelocatedabout3,300feetfromthenearestproposednewturbines.
AsdiscussedunderImpactNOI‐1a,therearenodocumentedinstancesofwindturbinescausingexceedanceofnoisestandardsintheexistingCUPs.Inaddition,proposedmodernturbineshaveseveralcharacteristicsthatreduceaerodynamicsoundlevelsandmakeforquieteroperationsthantheexistingturbines.Themodernturbineshaverelativelylowrotationalspeedsandpitchcontrolontherotors,bothofwhichreducesoundlevels.
ThenoisepredictionresultsinTable3.11‐5indicatethatresidenceslocatedwithinabout1,750feetofagroupofturbinescouldbeexposedtonoisethatexceeds55dBA(Ldn)orincreasesinnoisegreaterthan5dB.ThenoisepredictionresultsinTable3.11‐6alsoindicatethatresidenceslocatedwithinabout1,000feetofagroupofturbinescouldbeexposedtonoisethatexceeds70dBC(Ldn).Becausethenearestresidencewouldbemorethan3,000feetfromthenewturbines,operationofthenewturbinesisnotexpectedtoresultinnoisethatexceeds55dBA(Ldn),70dBC(Ldn)orresultina5dBAincreaseinnoiseatresidences.Theoperationalnoiseimpactisconsideredtobelessthansignificant.Nomitigationisrequired.
Alameda County Community Development Agency Impact Analysis
Noise
APWRA Repowering Draft PEIR 3.11‐15
June 2014ICF 00323.08
ImpactNOI‐2a‐1:Exposureofresidencestonoiseduringdecommissioningandnewturbineconstruction—programAlternative1:417MW(lessthansignificantwithmitigation)
Construction Equipment Noise
ProgramAlternative1wouldgenerallyinvolvethefollowingconstructionphases.
Phase1—Decommissioningofexistingwindturbinesandfoundationremoval
Phase2—Constructionoflaydownareas,substationsandswitchyards
Phase3—Roadconstruction
Phase4—Constructionofwindturbinegenerator(WTG)foundationsandbatchplant
Phase5—WTGdeliveryandinstallation
Phase6—Utilitycollectorlineinstallation
Phase7—Cleanupandrestoration
Table3.11‐7liststheconstructionequipmentthatisexpectedtobeusedforeachconstructionphase,basedontheassumptionsprovidedinAppendixD.
Table 3.11‐7. Construction Phases and Equipment
ConstructionPhase Equipment
1—Decommissioningandfoundationremoval
Crane,truckandlowboytrailer,excavator,grader,dumptruck
2—Laydownareas,substationsandswitchyardsconstruction
Roadgrader,tracktypedozer,drumtypecompactor,watertruck,truckandlowboytrailer,backhoe/frontloader
3—Roadconstruction Roadgrader,tracktypedozer,drumtypecompactor,watertruck,truckandlowboytrailer,backhoe/frontloader,excavator,rockcrusher
4—WTGfoundationsandbatchplant Roadgrader,tracktypedozer,drumtypecompactor,watertruck,truckandlowboytrailer,backhoe/frontloader,excavator,rockcrusher,cementtruck
5—WTGdeliveryandinstallation Crane,truckandlowboytrailer,excavator
6—Utilitycollectorlineinstallation Watertruck,backhoe/frontloader,trencher,horizontaldirectionaldrilling(HDD)boremachine
7—Cleanupandrestoration Roadgrader,excavator
Source:AppendixD.
Table3.11‐8summarizestypicalnoiselevelsproducedbyanticipatedconstructionequipment(FederalHighwayAdministration2006).Lmaxsoundlevelsat50feetareshownalongwiththetypicalacousticalusefactors.Theacousticalusefactoristhepercentageoftimeeachpieceofconstructionequipmentisassumedtobeoperatingatfullpower(i.e.,itsnoisiestcondition)duringconstructionoperationandisusedtoestimateLeqvaluesfromLmaxvalues.Forexample,theLeqvalueforapieceofequipmentthatoperatesatfullpower50%ofthetime(acousticalusefactorof50)is3dBlessthantheLmaxvalue.
Alameda County Community Development Agency Impact Analysis
Noise
APWRA Repowering Draft PEIR 3.11‐16
June 2014ICF 00323.08
Table 3.11‐8. Typical Construction Equipment Noise Levels
EquipmentTypeTypicalLmaxNoiseLevelat50FeetfromSource(dBA)
AcousticalUseFactor(%)
LeqNoiseLevelat50FeetfromSource(dBA)
Cementtruck 79 40 75
Compactor 83 20 76
Crane 81 16 73
Dozer 82 40 78
Dumptruck 76 40 72
Excavator 81 40 77
Flat‐bedtruck 74 40 70
Front‐endloader 79 40 75
Grader 85 40 81
HDDboremachine 82 25 76
Rockcrusher 85 50 82
Trencher 80 50 77
Watertruck 76 40 72
Source:FederalHighwayAdministration2006.
Table3.11‐9summarizesthecombinednoiselevelofequipmentassociatedwitheachconstructionphase.
Table 3.11‐9. Combined Noise Level by Construction Phase
ConstructionPhase
LmaxNoiseLevelat50FeetfromSource(dBA)
LeqNoiseLevelat50FeetfromSource(dBA)
1—Decommissioningandfoundationremoval 88 83
2—Laydownareas,substationsandswitchyardsconstruction 89 85
3—Roadconstruction 91 87
4—WTGfoundationsandbatchplant 95 86
5—WTGdeliveryandinstallation 84 79
6—Utilitycollectorlineinstallation 86 81
7—Cleanupandrestoration 86 82
Basedongeometricattenuationof6dBperdoublingofdistanceandadditionalattenuationresultingfromgroundabsorptionandatmosphericeffects,potentialconstructionnoiselevelsatvariousdistancesforeachconstructionphasehavebeencalculatedrelativetotheAlamedaCountynoiseordinancestandards.Table3.11‐10summarizestheresultsofthisanalysisandidentifiesdistanceswithinwhichAlamedaCountynoisestandardscouldbeexceededasaresultoftheconstructionactivities.ThecalculationsofconstructionequipmentnoiselevelsareincludedinAppendixD.
Alameda County Community Development Agency Impact Analysis
Noise
APWRA Repowering Draft PEIR 3.11‐17
June 2014ICF 00323.08
Table 3.11‐10. Construction Noise Analysis
ConstructionPhase
DaytimeHours(7a.m.to10p.m.) NighttimeHours(10p.m.to7a.m.)
Distance(feet)to70dBALmax
Distance(feet)to50dBALeq
Distance(feet)to65dBALmax
Distance(feet)to45dBALeq
1—Decommissioningandfoundationremoval
235 820 345 1,105
2—Laydownareas,substationsandswitchyardsconstruction
260 910 385 1,225
3—Roadconstruction 290 1,130 460 1,520
4—WTGfoundationsandbatchplant
435 1,035 625 1,390
5—WTGdeliveryandinstallation
170 545 270 865
6—Utilitycollectorlineinstallation
190 675 285 1,075
7—Cleanupandrestoration
205 750 300 1,190
Inanumberofinstances,thereareresidenceslocated600to800feetofwhereturbineconstructionactivitiescouldoccur.TheresultsinTable3.11‐10indicatethatconstructionactivitiescouldresultinnoisethatexceedsAlamedaCountynoiseordinancestandardsduringnonexempthours.Therefore,theexposureofresidencestoconstructionequipmentnoiseisconsideredtobeasignificantimpact.ImplementationofMitigationMeasureNOI‐2wouldreducethisimpacttoaless‐than‐significantlevel.
MitigationMeasureNOI‐2:Employnoise‐reducingpracticesduringdecommissioningandnewturbineconstruction
Projectapplicantswillemploynoise‐reducingconstructionpracticessothatconstructionnoisedoesnotexceedAlamedaCountynoiseordinancestandards.Measurestolimitnoisemayincludethefollowing:
Prohibitnoise‐generatingactivitiesbefore7a.m.andafter7p.m.onanydayexceptSaturdayorSunday,andbefore8a.m.andafter5p.m.onSaturdayorSunday.
Locateequipmentasfaraspracticalfromnoisesensitiveuses.
Requirethatallconstructionequipmentpoweredbygasolineordieselengineshavesound‐controldevicesthatareatleastaseffectiveasthoseoriginallyprovidedbythemanufacturerandthatallequipmentbeoperatedandmaintainedtominimizenoisegeneration.
Usenoise‐reducingenclosuresaroundnoise‐generatingequipmentwherepracticable.
ImplementothermeasureswithdemonstratedpracticabilityinreducingequipmentnoiseuponpriorapprovalbytheCounty.
Innocasewilltheapplicantbeallowedtousegasolineordieselengineswithoutmuffledexhausts.
Alameda County Community Development Agency Impact Analysis
Noise
APWRA Repowering Draft PEIR 3.11‐18
June 2014ICF 00323.08
Construction Traffic Noise
BasedontheanalysisforVascoWindRepoweringProject(ContraCostaCounty2010),whichisintheprogramvicinity,anddataprovidedbytheprojectapplicants,atypical80MWrepoweringprojectintheprogramareaisanticipatedtogenerateanaverageof420vehicletripsperday(300trucktripsand120workertrips)throughthecourseoftheconstructionperiod.TheconstructiontrafficnoiseimpactisevaluatedusingtherecenttrafficvolumescollatedonPattersonPassRoad,whichisconsideredasatypicalmajorcountyroadthatwouldbeusedforconstructioncrewstoaccesstheprojectarea.ThetrafficvolumesalongPattersonPassRoadareabout2,700to3,700vehiclesperday(AlamedaCounty2013).Theconstructiontrafficincreasewouldincreasetrafficnoisebylessthan2dB,whichwouldnotbeanoticeableincreaseatnearbyresidentialusesalongthemajorcountyroads.Therefore,thetrafficnoiseimpactduringconstructionisconsideredtobelessthansignificant.
ImpactNOI‐2a‐2:Exposureofresidencestonoiseduringdecommissioningandnewturbineconstruction—programAlternative2:450MW(lessthansignificantwithmitigation)
Construction Equipment Noise
ProgramAlternative2wouldgenerallyinvolvethefollowingconstructionphases.
Phase1—Decommissioningofexistingwindturbinesandfoundationremoval
Phase2—Constructionoflaydownareas,substationsandswitchyards
Phase3—Roadconstruction
Phase4—Constructionofwindturbinegenerator(WTG)foundationsandbatchplant
Phase5—WTGdeliveryandinstallation
Phase6—Utilitycollectorlineinstallation
Phase7—Cleanupandrestoration
Table3.11‐7liststhecequipmentthatisexpectedtobeusedforeachconstructionphase,basedontheassumptionsprovidedinAppendixD.
Table3.11‐8summarizestypicalnoiselevelsproducedbyanticipatedconstructionequipment(FederalHighwayAdministration2006).Lmaxsoundlevelsat50feetareshownalongwiththetypicalacousticalusefactors.Theacousticalusefactoristhepercentageoftimeeachpieceofconstructionequipmentisassumedtobeoperatingatfullpower(i.e.,itsnoisiestcondition)duringconstructionoperationandisusedtoestimateLeqvaluesfromLmaxvalues.Forexample,theLeqvalueforapieceofequipmentthatoperatesatfullpower50%ofthetime(acousticalusefactorof50)is3dBlessthantheLmaxvalue.
Table3.11‐9summarizesthecombinednoiselevelofequipmentassociatedwitheachconstructionphase.
Basedongeometricattenuationof6dBperdoublingofdistanceandadditionalattenuationresultingfromgroundabsorptionandatmosphericeffects,potentialconstructionnoiselevelsatvariousdistancesforeachconstructionphasehavebeencalculatedrelativetotheAlamedaCountynoiseordinancestandards.Table3.11‐10summarizestheresultsofthisanalysisandidentifiesdistanceswithinwhichAlamedaCountynoisestandardscouldbeexceededasaresultofthe
Alameda County Community Development Agency Impact Analysis
Noise
APWRA Repowering Draft PEIR 3.11‐19
June 2014ICF 00323.08
constructionactivities.ThecalculationsofconstructionequipmentnoiselevelsareincludedinAppendixD.
Inanumberofinstances,thereareresidenceslocated600to800feetofwhereturbineconstructionactivitiescouldoccur.TheresultsinTable3.11‐10indicatethatconstructionactivitiescouldresultinnoisethatexceedsAlamedaCountynoiseordinancestandardsduringnonexempthours.Therefore,theexposureofresidencestoconstructionequipmentnoiseisconsideredtobeasignificantimpact.ImplementationofMitigationMeasureNOI‐2wouldreducethisimpacttoaless‐than‐significantlevel.
MitigationMeasureNOI‐2:Employnoise‐reducingpracticesduringdecommissioningandnewturbineconstruction
Construction Traffic Noise
BasedontheanalysisforVascoWindRepoweringProject(ContraCostaCounty2010),whichisintheprogramvicinity,anddataprovidedbytheprojectapplicants,atypical80MWrepoweringprojectintheprogramareaisanticipatedtogenerateanaverageof420vehicletripsperday(300trucktripsand120workertrips)throughthecourseoftheconstructionperiod.TheconstructiontrafficnoiseimpactisevaluatedusingtherecenttrafficvolumescollatedonPattersonPassRoad,whichisconsideredasatypicalmajorcountyroadthatwouldbeusedforconstructioncrewstoaccesstheprojectarea.ThetrafficvolumesalongPattersonPassRoadareabout2,700to3,700vehiclesperday(AlamedaCounty2013).Theconstructiontrafficincreasewouldincreasetrafficnoisebylessthan2dB,whichwouldnotbeanoticeableincreaseatnearbyresidentialusesalongthemajorcountyroads.Therefore,thetrafficnoiseimpactduringconstructionisconsideredtobelessthansignificant.
ImpactNOI‐2b:Exposureofresidencestonoiseduringdecommissioningandnewturbineconstruction—GoldenHillsProject(lessthansignificantwithmitigation)
ConstructionnoiselevelsassociatedwithanticipatedconstructionphasesandequipmentforrepoweringprojectsarediscussedunderImpactNOI‐2aandsummarizedinTables3.11‐7and3.11‐9.Table3.11‐10summarizesthedistanceswithinwhichAlamedaCountynoisestandardscouldbeexceededasaresultoftheconstructionactivities.
Inanumberofinstances,thereareresidenceslocatedwithin800feetofwhereturbineremovalandrestorationactivitiescouldoccur.TheresultsinTable3.11‐10indicatethattheseactivitiescouldresultinnoisethatexceedsAlamedaCountynoiseordinancestandardsduringnonexempthours.Thisimpactisthereforeconsideredtobesignificant.ImplementationofMitigationMeasureNOI‐2wouldreducethisimpacttoaless‐than‐significantlevel.
MitigationMeasureNOI‐2:Employnoise‐reducingpracticesduringdecommissioningandnewturbineconstruction
AsdiscussedunderImpactNOI‐2a‐1andNOI‐2a‐2,theconstructiontrafficincreasewouldincreasetrafficnoisebylessthan2dB,whichwouldnotbeanoticeableincreaseatnearbyresidentialusesalongthemajorcountyroads.Therefore,theimpactofconstructiontrafficnoiseisconsideredtobelessthansignificant.
Alameda County Community Development Agency Impact Analysis
Noise
APWRA Repowering Draft PEIR 3.11‐20
June 2014ICF 00323.08
ImpactNOI‐2c:Exposureofresidencestonoiseduringdecommissioningandnewturbineconstruction—PattersonPassProject(lessthansignificant)
ConstructionnoiselevelsassociatedwithanticipatedconstructionphasesandequipmentforrepoweringprojectsarediscussedunderImpactNOI‐2aandsummarizedinTables3.11‐7and3.11‐9.Table3.11‐10summarizesthedistanceswithinwhichAlamedaCountynoisestandardscouldbeexceededasaresultoftheconstructionactivities.
Becausetheclosestresidenceislocatedabout2,200feetfromthenearestturbines,whichisbeyondtheimpactdistancesidentifiedinTable3.11‐10,theconstructionnoiseimpactonresidencesisconsideredtobelessthansignificant.Nomitigationisrequired.
AsdiscussedunderImpactNOI‐2a‐1andNOI‐2a‐2,theconstructiontrafficincreasewouldincreasetrafficnoisebylessthan2dB,whichwouldnotbeanoticeableincreaseatnearbyresidentialusesalongthemajorcountyroads.Therefore,theimpactofconstructiontrafficnoiseisconsideredtobelessthansignificant.
3.11.3 References Cited
AlamedaCounty.1976.GeneralPlanNoiseElement.AdoptedJanuary8.AmendedMay5,1994.
———.2000.EastCountyAreaPlan.AdoptedMay1994.Oakland,CA.ModifiedbypassageofMeasureD,effectiveDecember22,2000.Available:http://www.acgov.org/cda/planning/generalplans/index.htm.Accessed:March1,2013.
———.2013.PattersonPassRoadandTeslaRoadSafetyStudy.PublicMeetingPresentationonMarch27.AlamedaCountyPublicWorksAgency.Available:http://www.acgov.org/pwa/updates/pattersonpassstudy.htm.Accessed:June27,2013.
AustraliaNationalHealthandMedicalResearchCouncil.2010.WindTurbinesandHealth:ARapidReviewoftheEvidence.July.
Bowdler,D.2008.AmplitudeModulationofWindTurbineNoise:AReviewoftheEvidence.InstituteofAcousticsBulletin33(4).
CaliforniaDepartmentofTransportation.2009.TechnicalNoiseSupplementtotheTrafficNoiseAnalysisProtocol.November.Available:http://www.dot.ca.gov/hq/env/noise/.Accessed:March1,2013.
Colby,W.D.,R.Dobie,G.Leventhall,D.M.Lipscomb,R.J.McCunney,M.T.Seilo,B.Sondergaard.2009.WindTurbineSoundandHealthEffects:AnExpertPanelReview.December.PreparedforAmericanWindEnergyAssociationandCanadianWindEnergyAssociation.
ContraCostaCounty.2010.VascoWindsRepoweringProjectDraftEnvironmentalImpactReport.December.DepartmentofConservationandDevelopment.Martinez,CA.
FederalHighwayAdministration.2006.FHWARoadwayConstructionNoiseModelUser’sGuide.FHWA‐HEP‐05‐054.January.
Governor’sOfficeofPlanningandResearch.2003.StateofCaliforniaGeneralPlanGuidelines.Sacramento,CA.Available:http://www.opr.ca.gov.Accessed:March1,2013.
Alameda County Community Development Agency Impact Analysis
Noise
APWRA Repowering Draft PEIR 3.11‐21
June 2014ICF 00323.08
Hoover,R.M.,andR.H.Keith.2000.Noise Control for Buildings, Manufacturing Plants, Equipment, and Products. Lecturenotes,firstpublished1981.Houston,TX:Hoover&KeithInc.
ICFInternational.2013.NoiseTechnicalReportfortheSandHillWindProject,AlamedaCounty,CA.Draft.June.Sacramento,CA.
Illingworth&Rodkin.2006.MontezumaWindProjectNoiseTechnicalReport,SolanoCounty,California.Petaluma,CA.
O’NealR.D.,R.D.Hellweg,Jr.,R.M.Lampeter.2010.LowFrequencySoundandInfrasoundfromWindTurbines.April.AcousticalSocietyofAmerica,159thMeetingLayLanguagePapers.
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