value engineering report - lca v terrebonne final/appendices...value engineering study report...

APPENDIX H

VALUE ENGINEERING REPORT

ValueEngineeringStudyReport

TerrebonneBasinBarrierShorelineRestorationMultipurposeOperationofHoumaNavigationLock

ConveyAtchafalayaRiverWatertoNorthernTerrebonneMarshes

CEMVNVE0904

June2009

Preparedby

ValueManagementStrategies,Inc.

Date: July8,2009

FrankVicidomina,ValueEngineeringOfficerU.S.ArmyCorpsofEngineersNewOrleansDistrict2608SellsStreetMetairie,Louisiana70003

Subject: ValueEngineeringStudyReportFinal TerrebonneBasinBarrierShorelineRestoration MultipurposeOperationofHoumaNavigationLock ConveyAtchafalayaRiverWatertoNorthernTerrebonneMarshes

Mr.Vicidomina:

ValueManagementStrategies,Inc.ispleasedtotransmit15papercopiesand25copiesonCDoftheFinalValueEngineeringStudyReport.ThisreportsummarizestheresultsandeventsofthestudyconductedMay58,2009,inNewOrleans,Louisiana.

We enjoyed working with you and are looking forward to continuing ourefforts toassist theNewOrleansDistrictU.S.ArmyCorpsofEngineers in itsvalueengineeringefforts.

Sincerely,

VALUEMANAGEMENTSTRATEGIES,INC. MarkWatson,PE,CVSVEStudyTeamLeader

ValueLeadership

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TerrebonneBasinBarrierShorelineRestorationMultipurposeOperationofHoumaNavigationLockConveyAtchafalayaRiverWatertoNorthernTerrebonneMarshes TableofContents

TABLEOFCONTENTS FINALREPORT

EXECUTIVESUMMARY..........................................................................................................1.1 INTRODUCTION.................................................................................................................1.1 VESTUDYRESULTS............................................................................................................1.1 TerrebonneBasinBarrierShorelineRestoration.................................................1.1 MultipurposeOperationofHoumaNavigationLock...........................................1.2 ConveyAtchafalayaRiverWatertoNorthernTerrebonneMarshes...................1.2 General/PlanFormulation....................................................................................1.3 SUMMARYOFVEALTERNATIVECONCEPTS.....................................................................1.3

VEALTERNATIVECONCEPTS..................................................................................................2.1 TERREBONNEBASINBARRIERSHORELINERESTORATION...............................................2.1 MULTIPURPOSEOPERATIONOFHOUMANAVIGATIONLOCK.......................................2.13 CONVEYATCHAFALAYARIVERWATERTONORTHERNTERREBONNEMARSHES..........2.24 GENERAL/PLANFORMULATION.....................................................................................2.32

PROJECTANALYSIS................................................................................................................3.1 SUMMARYOFANALYSIS...................................................................................................3.1 KEYPROJECTFACTORS.....................................................................................................3.2 FUNCTIONANALYSIS/FASTDIAGRAM............................................................................3.3

PROJECTINFORMATION........................................................................................................4.1 INTRODUCTION.................................................................................................................4.1 PROJECTBACKGROUND....................................................................................................4.1 PROJECTDESCRIPTIONS....................................................................................................4.1 TerrebonneBasinBarrierShorelineRestoration.................................................4.1 MultipurposeOperationofHoumaNavigationLock...........................................4.3 ConveyAtchafalayaRiverWatertoNorthernTerrebonneMarshes...................4.3 INFORMATIONPROVIDEDTOTHEVETEAM....................................................................4.5

IDEAEVALUATION................................................................................................................5.1 INTRODUCTION.................................................................................................................5.1 PERFORMANCEATTRIBUTES............................................................................................5.1 EVALUATIONPROCESS.....................................................................................................5.2 IDEAEVALUATION............................................................................................................5.2

VALUEENGINEERINGTEAMANDPROCESS...........................................................................6.1 VETEAMANDPROCESS....................................................................................................6.1 MEETINGATTENDEES.......................................................................................................6.3

TerrebonneBasinBarrierShorelineRestorationMultipurposeOperationofHoumaNavigationLockConveyAtchafalayaRiverWatertoNorthernTerrebonneMarshes TableofContents

APPENDICES

A. CoastalImpactAssistanceProgramApplicationHoumaNavigationCanalLock,May22,2006;TerrebonneLeveeConservationDistrict

B. Conceptualfloatingbargegatedesigns

C. VEStudyBayouLafourcheSiphonRestorationProject,July2001;ProposalC1

D. PreparationofaMultiProjectEnvironmentalAssessmenttoevaluatethepotentialenvironmentalimpactsassociatedwiththeremovalofsandresourcesfromShipShoal,offshoreCentralLouisiana

E. LouisianaSandManagementWorkingGroupMeetingMinutes,2February2005

F. InformationonRelativeSeaLevelRiseaspreparedbyKevinKnuuti,P.E.,Chief,EngineeringDivision,U.S.ArmyCorpsofEngineers,Sacramento,CA

G. MultiPitBreakwaters,JournalofWaterway,Port,Coastal,andOceanEngineering,WilliamG.McDougal,A.NeilWilliams,andKeizoFurukawa,January/February1996

H. MMSManagementofOuterContinentalShelfMaterialDepositsandrelatedinformation

EXECUTIVESUMMARY

TerrebonneBasinBarrierShorelineRestorationMultipurposeOperationofHoumaNavigationLockConveyAtchafalayaRiverWatertoNorthernTerrebonneMarshes ExecutiveSummary1.1

EXECUTIVESUMMARY FINALREPORT

INTRODUCTION

ThisValueEngineering (VE)StudyReportsummarizes theeventsof theVEworkshopconductedMay58,2009 for theU.S.ArmyCorpsofEngineers (USACE),NewOrleansDistrict,byValueManagementStrategies,Inc. The subjectof the studywas the TerrebonneBasinBarrier ShorelineRestorationproject, theHoumaNavigationGateOperationsPlan,andtheConveyAtchafalayaRiverWatertoNorthernTerrebonneMarshesproject.

This studywas conducted at the Feasibility ScopingReport/PreliminaryDraft EIS, an early stageofprojectdevelopment,andassuchisthebeginningofplanformulation.

VESTUDYRESULTS

TheVEteamdeveloped38alternativeconceptswhichareintendedtoassisttheUSACEinbetterformulatingplanstocarryforwardintothenextphaseofdevelopment.

These recommendations are categorized per subject project aswell as those that pertain to general planformulation.

Majorfindingsoftheworkshoparesummarizedasfollows:

TerrebonneBasinBarrierShorelineRestoration

The natural processes of subsidence and erosion have combined with humancaused effects leading tosignificantshorelineretreatandlandlossalongtheTerrebonneBasinbarrierislandchain.Assuch,thesystemis in a continuous need of sediment. The current project plans and budget only allow for a singlerenourishmentafteraboutfiveyears,whichmeansthesustainabilityoftheprojectisindoubt.Furthermore,theavailabilityofsuitablesedimentfromShipShoaltorestoreandmaintainthebarrierislandsmaybelimited.Finally,thebarrierislandchainformsacomplexsystemofecological,physical,chemical,andsocialprocesses,whichinteractinahighlyinvolvedand,attimes,dynamicfashion.

KeyVEalternativesidentifiedtoaddresstheseissuesareasfollows:

SustainBarrierIslandSystem

o Obtainacleardefinitionoftheprojectobjectivesregardingsustainability

o Establishpermanenttrustfundforrenourishmentcosts

ProvideSedimentforRenourishment

o UseMineralsManagementService(MMS)toregulateShipShoalquantitiestovariousprojectsneedingsediment

o ConstructapermanentpipelinefromShipShoaltotheeastendofEastTimbalierIsland


o UtilizeDynamicCoastalSystems

o Utilizesandrecycling/backpassingforbarrierislandnourishment

o Considercoastalgeomorphicprocessesforsedimentplacement

o Constructnewbarrierislandchainclosertonewshoreline

ProtectSediment

o Installinvertedbreakwatersanduseexcavatedmaterialtoconstruct/replenishbackmarsh

o Fixbarrierislandsintheircurrentlocation,eliminatingorminimizingislandrollover,byincorporatingahardcoreorallowsurfacearmoring

MultipurposeOperationofHoumaNavigationLock

TheHoumaNavigationCanal(HNC)lockandfloodgatewereplannedoveradecadeago.ThepossibleadditionofayearroundsignificantfreshwaterflowintotheHNCfromtheproposedAtchafalayaRiverDiversionProjectwouldsignificantlyaffecttheoperationofthelockandfloodgateandperhapsevenwarrantreconsiderationofthefacilitydesign.Thelockandgatecomplexwillhavetobalancetheimpactstonavigationwiththenecessityofprotectingthe interiorfromtidalsurgeandsalinity. Finally,thepotentialfutureglobalsea level(GSL)riseimpactswhattypeoffacilityshouldbeconstructed.

KeyVEAlternativesidentifiedtoaddresstheseissuesareasfollows:

OptimizeholisticsystembybalancingHNCflowratecapacitywithgateandlockdesignandoperationplan

Developasetofguidelinesforwhengatewillbeshutand installmonitorsandcontrolstoautomaticallyclosegate

Configureproposed250footfloodgatesuchthatanadditionalgatecouldbeaddedinthefutureinordertoupgradetoalocktoaccommodateapossiblehigherthanexpectedfuturesealevel


Issues with this project are that freshwater and sediment has poor delivery to the wetlands due to 1)alterationsinnaturalhydrologicflow(canals,etc.),2)constrictionsintheGulfIntracoastalWaterway(GIWW)that reduce freshwater flow to the subunit, and 3) freshwater delivered to the HNC bypasses adjacentwetlands and delivers to theGulf ofMexico. The project is also having to identifywhere the freshwaterneededshouldbederivedfromandhowitshouldbedeliveredtotheareasthatneedit.

Finally,seasonaldifferencesintheneedforfreshwaterandnutrients,andthelocationsfromwhichfreshwatercan be recruited and distributed,may have conflicting parameters (i.e., freshwater is particularly neededduringperiodsoflowflowintherivers).


KeyVEalternativesidentifiedtoaddresstheseissuesareasfollows:

GIWWConstrictionatHouma

o LouisianaDepartmentofTransportationandDevelopment (LADOTD) tobuildahighrisebridgeandtakethetunneloutofservice

o InstallachannelsectionthroughtheTwinSpanbridge

AddressFreshwaterQuantityLimitations

o AlterOldRiverControlStructuretodivertmorethan70/30allocation

o Developaseasonalfreshwatermanagementplan

o InstallwickergatesonHNCcutsintothemarsh

AddressFreshwaterSourceandTransport

o UseBayouLafourchetoconveyfreshwatertothenorthernTerrebonnemarshes

General/PlanFormulation

DevelopPlanStrategiesthataccountformuchhigherlevelsofGSLrise

One issue addressed by the VE team spans all three projects and has ramifications throughout theLouisianaCoastalArea (LCA)program. All threeprojectsarecurrentlyassumingaminimumamountofrelativesealevelrise(combinationofsealevelriseandsubsidence).Currently,workisunderwaybytheUSACE,NationalOceanic andAtmosphericAdministration (NOAA),andUnited StatesGeological Survey(USGS) to investigate the glacialmelt contribution to future GSL rise. Project benefits depend uponhabitatsmaintainedabovesealevel.Consequently,benefitsbeyondthe50yearplanninghorizonwillbelost if subsidence andGSL rise exceed the current assumptions. The rate ofGSL rise in the future iscurrentlyunknown,butcouldbemuchgreaterthanthecurrentassumptions.Assuch,theprojectsshoulddevelopspecificPlanStrategiesthatconsidertherangeofpossiblefutureGSLrates.

SUMMARYOFVEALTERNATIVECONCEPTS

ThetablethatfollowssummarizesallofthealternativeconceptsdevelopedbytheVEteam.Theitemsinredtextwere identified by the VE team as items of particular note and key recommended strategies for theProjectDevelopmentTeam(PDT)toconsider.


SUMMARYOFVEALTERNATIVECONCEPTSTerrebonneBasinBarrierShorelineRestoration,MultipurposeOperationofHoumaNavigationLock,


Number Description

TerrebonneBasinBarrierShorelineRestoration

T1 Installinvertedbreakwatersanduseexcavatedmaterialtoconstruct/replenishbackmarsh

T2 Obtainacleardefinitionoftheprojectobjectivesregardingsustainability

T3 Establishpermanenttrustfundforrenourishmentcosts

T4 ConstructapermanentpipelinefromShipShoaltotheeastendofEastTimbalierIsland

T5 Conductoffshoresedimentanalysistoidentifyalternativesourcesofbarrierislandrenourishmentsediment

T6 Considerwindpoweredfixeddredgedsedimentsupply

T7 UseMMStoregulateShipShoalquantitiestovariousprojectsneedingsediment

T8 Considercoastalgeomorphicprocessesforsedimentplacement

T9 Utilizesandrecycling/backpassingforbarrierislandnourishment

T10 Fixbarrierislandsintheircurrentlocation,eliminating/minimizingislandrollover,byincorporatingahardcore(e.g.,buriedsandfilledGeotubes,revetments)orallowsurfacearmoring(e.g.,revetments,rock,concrete)

T11 Constructgroinsand/orbreakwaterswithprefilledsediment

T12 Constructnewbarrierislandchainclosertonewshoreline

T13 Establishanenvironmentaldredgingfleet

T14 Prioritizeprojectcomponentsbasedonmarshlossfactors

T15 AddPlanStrategythataddresseshabitatneedsinexcessofbudgetarylimitations

T16 Implementoil/gasindustryoutreachprogramregardingfuturesedimentmanagement

T17 Changethetermnonstructuralinprojectdocumentstosoftstructural

HoumaNavigationGateOperationsPlan

H1 OptimizeholisticsystembybalancingHNCflowratecapacitywithgateandlockdesignandoperationplan

H2 Developasetofguidelinesforwhengatewillbeshutandinstallmonitorsandcontrolstoautomaticallyclosegate

H3 InstallflowcontrolonHNCcutsintothemarsh

H4 Configureproposed250footfloodgatesuchthatanadditionalgatecouldbeaddedinthefutureinordertoupgradetoalock


Number Description

H5 Extendutilizationoftemporarybargegateanddeferconstructionofnewsectorgate

H6 Considerusingafloatablebargegateinlieuofasectorgate

H7 Constructconcretesectorgatesorutilizeothermaintenancefavorablematerials


A1 AddressflowconstrictionsintheGIWWatHouma

A2 OperatetheOldRiverControlStructuretooptimizeflowsplitoutsideofthe70/30mandateinnonfloodconditions

A3 UseCityofHoumawastewatereffluenttoreplenishcypressforests

A4 PumpflowfromDavisPondDiversionfromCompanyCanal

A5 UseBayouLafourchetoconveyfreshwatertothenorthernTerrebonnemarshes

A7 Ensurethatlocalfishinginterestsarefullyinformedofprojectalternativeimpacts

A6 ConstructminiWoodysDitcheastofHoumaandwestofBayouLafourcheconnectingtheMississippiRivertoLakeFields

A8 RequireoilcompaniestoplugcanalsconnectingtoGIWW

A9 InstallnutriafencingalongGIWWandbirthcontrolmeasuresthroughoutprojectarea

General/PlanFormulation

G1 DevelopPlanStrategiesthataccountformuchhigherlevelsofglobalsealevelrise

G2 Developaseasonalfreshwatermanagementplan

G3 Createfederaladvisorycommittee

G4 Identifyandincorporatetheeffectsofsubsidencefromfluidwithdrawalintheprojectanalysisanddesign;utilizewaterinjectiontominimizetheimpactsoffluidwithdrawalinducedsubsidence

G5 Consideralternateprocurementmethodsforconstruction

VEALTERNATIVECONCEPTS

TerrebonneBasinBarrierShorelineRestorationMultipurposeOperationofHoumaNavigationLockConveyAtchafalayaRiverWatertoNorthernTerrebonneMarshes VEAlternativeConcepts2.1

VEALTERNATIVECONCEPTS FINALREPORT

TERREBONNEBASINBARRIERSHORELINERESTORATION

T1 Installinvertedbreakwatersanduseexcavatedmaterialtoconstruct/replenishbackmarsh

This project faces a severe shortage of suitablematerial for island/dune construction aswell as the backmarsh. Apotentialgoodsourceofbackmarshmaterialmayexist justoffshoreofthebarrier islandsontheGulfside.Thismaterialcaneasilybedredgedandplacedonthelandsideoftheislandasthebaseforthebackmarsh.Withthisexcavationcomesanotheradvantage,theconstructionofaninvertedbreakwaterontheGulfsideinfrontoftheisland.

Theconstructionofinvertedbreakwatersparalleltothebeachisasimpleconceptthatcouldprovetobeverycost effective aswell as physically effective for normalwave activity. They could even be constructed intandemwithoffshoreshoals.Theconceptisdepictedinthesketchbelow.

The argument against inverted breakwaters is that the inverted breakwatersmay trap some of the sanderodingfromthebeach,andthusnegativelyimpactthelittoraldrift.However,thecurrentlittoraldriftcarriesminimalsedimentsotheeffectdowndriftshouldalsobeminimal.

Theadvantageofthisapproachisthepotentialforobtainingsedimentclosetopointsofplacementatalowercost to the project. In addition, the initialwave heightswill be diminished by the inverted breakwater,reducingimpactenergyalongtheshorelineandallowingmoretimeforstabilizationofplantings.Overtimeitisprobablethatmovementofsedimentwillfillintheinvertedbreakwaterbecause,atthislocation,thereisadecreaseinwaveenergyandthetrenchactsasasedimenttrap.Butthiscouldbeseenasabenefitasthesetrencheswouldbecomeexcellent locationsformaterialneeded infuturemaintenancedredgingtorenourishandsustaintheprogram.

ApaperpublishedintheJournalofWaterway,Port,Coastal,andOceanEngineering(January/February1996)entitledMultiPitBreakwatersbyWilliamG.McDougal,A.NeilWilliams, andKeizo Furukawa assessed thebenefits of a submarine depression used as a breakwater. They found that the appropriate selection ofdepression (pit)dimensionsandplacementmay lead toasignificant reduction inwaveheightbehind thesestructures. Theshadow regionbehind thepitscan reduce thewaveheightsby10% to20%of the incidentwave height. This paper provides guidance on the selection of pit (inverted breakwater) geometries andplacementforoptimalbreakwaterperformance.AcopyofthispaperisprovidedinAppendixG.


These featureswould not be very effective in reducing significant storm surges, in the samemanner thatoffshore rock breakwaters would not be effective either. Further modeling and/or test reaches arerecommendedtoassesstheirapplicabilitytothisproject.

T2 Obtainacleardefinitionoftheprojectobjectivesregardingsustainability

The first environmental operating principle of theUSACE states that theUSACE should, Strive to achieveenvironmental sustainability, and recognize that an environment maintained in a healthy, diverse, andsustainable condition is necessary to support life. The sixth item listed in the 12 Actions for Changeindicates that theUSACE shouldfocuson sustainability. It is clear from theseprinciplesandactions thatsustainability is important to the USACE and, consequently, should be incorporated into USACE activities.However, theApril 2009 Feasibility ScopingMeetingReport (FSMR) doesnot contain anymention ofhowsustainability will be considered in plan formulation. Moreover, there is no definition of sustainabilityprovided in the FSMR. A clear definition of sustainability is needed in order to make sustainability ameaningfulprojectobjective.

Suchanobjectivemaybeestablishedasfollows:

SustainablewithresourceswithintheLCAuptotheYear2100basedonarange inrelativesea levelrise(e.g.,extrapolationofhistoricalratesofsealevelrise,acceleratedrateofsealevelriseperNRClowI,andacceleratedrateofsealevelriseperNRChighIII)nomatterwhatthecost.

T3 Establishpermanenttrustfundforrenourishmentcosts

GSLriseatthehighestratescombinedwithsubsidencecouldbeanetriseofnearly6feetbyYear2100andthusinundatingtheprojectarea.IftheLCAprojectsarenotcancelledbyCongressforthesereasons,thenanalternative concept requires repeated fill and restoration efforts to keep pace with both GSL rise andsubsidence. This isnotasustainablecondition,butdemandscontinuousrepeatedbeachrenourishmentandmarshplatformfillinperpetuity.PlacingfillattheratethatequalsthecombinedfasterrateofGSLratebasedon this current science,and theknown subsidence rates, inperpetuitywillbe vital for restoration success.Consequently, episodic (e.g., every five years)marsh platform fill and barrier island sand nourishment isessentialforecologicalrestorationsuccess.ProjectrenourishmentneedsbasedonjusttheNationalEcologicalRestoration(NER)processusingcosteffectiveincrementalcostaccounting(CEICA)justificationcannotprovideforperpetualecologicalneeds.

Congresstypicallychoosesnottoundertakefinancialobligationsrequiringfuturefundingforperpetualcosts.But Congressmay appropriate funds to establish a permanent trust fund and the interest accruedwouldprovideforperpetualcosts. Whilesuchcostsmaybe includedasoperationsandmaintenance (O&M)costsprovidedbystate,notfederal,funding,thenonlystateassets,notnationalassets,areaccessible. However,support isgrowing inCongress for certainpermanent trust funds, for residentialhousing forexample, thatwouldbuildonsuccessfultrustfundmodelsbystatesandtribes. Byfarthe largest isthe$26billionAlaskaPermanentFund.

Apossibleexampleforabeachrenourishmentpermanenttrustfund:AmultivariantanalysisofthecoststoassuredredgingandplacementofsandfromShipShoaltotheTerrebonnebarrierislandsbasedontheabovevariousratesofGSLrise isperformedtodeterminetheprojectedrangeofperpetualfundingneeded. If,forexample,anannualbeachrenourishmentcostof$5millionisrequiredtokeeppacewiththeacceleratedrateofGSLrise,thenapermanentbeachrenourishmenttrustfundof$166millionyielding3%annuallywouldbe


needed. (Should this trust fund yield exceed renourishment requirements, the trust fund may grow oralternativelyannualnetexcesscanbereturnedtotheU.S.Treasury.)

References:NOAA,SeaLevelsOnline.http://tidesandcurrents.noaa.gov/sltrends/sltrends.shtml

T4 ConstructapermanentpipelinefromShipShoaltotheeastendofEastTimbalierIsland

OneofthepotentialmethodsforbarrierislandconstructionandrenourishmentbeingconsideredbythePDTistocreatefeederbeachesthatmayerode intothe littoraldrifttransferringsandtobedepositedonbarrierislandstothewest. Theprimary locationforsuchafeederbeachwouldbetheeastendofEastTimbalierIsland. Typically, thiswould involve periodically bringing in a dredge to Ship Shoal, laying a pipeline, andtransferringsandtothefeederbeach.

If the design team determines that there is benefit to identifying a permanent location for deposition ofrenourishmentsandatEastTimbalierIsland,itmaybepossibletolayapermanentpipelineforthedredgetohook up to. The pipeline could terminate on land, though this may create an issue with excessiveaccumulation of sand in a small area thatmight plug the pipe and prevent full deposition of the desiredvolumeofsand.Itmaybepreferabletoterminatethesandwithinthelittoraldriftcurrentitselfratherthanondry land so that the sandbegins its journey to thewest immediatelyafter itexits thepipe. AkeyconcernwouldbesitingthepipelinetoavoidorminimizeimpactstoexistingoilandgasfacilitieslocatedbetweenShipShoalandEastTimbalierIsland.

AfurtherrefinementofthisideawouldbetoconstructapermanentdredgingplantatShipShoaltofeedthispipeline. This dredge could be powered by green technologies (wind, solar) as discussed in anotherproposal.

T5 Conductoffshore sedimentanalysis to identifyalternative sourcesofbarrier island renourishmentsediment

ThePDThasindicatedthatamajorconstraintinachievingtheprojectobjectivesistheavailabilityofsuitablesedimenttorestoreandmaintainthebarrierislands.AlthoughShipShoalwasidentifiedasasedimentsourcewith known reserves of sand, there are numerous projects in the LCA that are planning to utilize thesesedimentresources.Inaddition,ShipShoalisbetween50and100milesfromthebarrierislandsdependingontheexactlocationwithinShipShoalandtheislandthatisbeingrestoredwithsandfromthissedimentsource.Consequently,thecostofrestoringthe islandscouldbereducedsignificantly ifalternativesedimentsourcesclosertothe islandswereutilizedforrestorationactivities.Thesesourcesmayconsistofsandlayerslocatedbeneaththetopsectionsofnearshorebottoms.

Itissuggestedthatanoffshoresedimentsourceinvestigationbeconductedtoidentifyalternativesourcesofbarrier island restoration and nourishment sediment. The investigation would focus on the area in theimmediatevicinityoftheislandsandonthesidetowardstheGulfofMexico.Itmightbepossibletotapintotheoil/gasindustryforgeologicalinformation(e.g.,seismicrecordings,geologicallogs,andsedimentborings)to assist in conducting this investigation, thereby reducing the costs of the investigation. In addition, thisrecommendationcouldbeusedtosuggestfundingfortheMMStoconductthisinvestigationforthepurposeofmapping the sediment resources in the area sinceMMS is the federal agency responsible formanagingtheseoffshoreresources.


T6 Considerwindpoweredfixeddredgedsedimentsupply

DredgingfromShipShoaltotheTerrebonneIslandswillbebyperiodicuseofhopperdredgesmobilizedanddemobilizedeveryfivetotenyears.

ThisalternativeconceptinvolvesthepermanentplacementofacutterheadpipelinedredgeatShipShoalwiththepipelineterminusonEastTerrebonneIsland.Sanddepositedheresubtidallyisexpectedtoaccretetothebarrierislandsbylongshoredisplacement.

Twoboosterpumps(eitherkineticorpositivedisplacement)areneededtosupplementthedredgepumpdueto thedistance the sand slurry canbepumpedwithoutpipe sedimentation.Twoboosterpumpswouldbeinstalledtoformaseriesspacedequidistantfromthedredgesitetothedisposalsite.Adisplacementboosterpump used in combinationwith a centrifugal dredge pumpwould require a booster pump holding facilitybecauseitisdifficulttomatchpositivedisplacementpumpingratestocentrifugalpumpingrates.

Offshore Louisiana has potential forwind energy development according to two reports prepared for theDepartmentofEnergy in1979. OffshoreareaswestoftheMississippiRiverofferahighClass3/lowClass4wind energy resource. (Class 7 being maximum and Class 3 is the threshold for feasible wind powerdevelopment.)In2005,theLouisianalegislatureapprovedauthorityfortheStateMineralBoardtoleasestatelandsandwaterbottoms(i.e.,areaswithinthreemilesofshore)fortheproductionofwindenergy.

Topowertheseslurrypumps,three1.5MWcapacitywindturbinesandtowerswouldbeinstalled:oneattheShipShoalcutterheadandtwootherstopowertheboosterpumps.Windpowersupplyisinterruptible.Cutinwind speed,whenpower isproduced,beginsat3.5m/s (8.4mph). Because thewindpoweredelectricpumpswouldshutdownwhenthewindisbelowthecutinspeed,aflapvalveateachboosterstationwouldbeinstalledtodraintheslurrytopreventsedimentbuildupinthepipe.

The installedprice foreach1.5MWwind turbineand tower isestimatedat$17.5millionaccording to theDanishWind IndustryAssociation. General Electric produced over 10,000 1.5MW capacitywind turbinessuccessfullyoperatingsince1996andaremanufacturedatGEsPensacola,Floridaplant.

References:

Coastal ZoneWind Energy, Part II: Frequency Distribution ofWinds by Direction for East and Gulf CoastStations, Final Report,DOE/ET/2027477/78/798, prepared byMichaelGarstang and others,University ofVirginia,Charlottesville,VA,undercontractforU.S.DepartmentofEnergy;May1979.

DesignStudyandEconomicAssessmentofMultiUnitOffshoreWindEnergyConversionSystemsApplication,Vol. 1: Executive Summary, WASH233078/4 (Vol. 1), prepared by Westinghouse Electric Corporation,AdvancedSystemsTechnology,EastPittsburgh,PA,undercontract forU.S.DepartmentofEnergy; June14,1979.

DanishWindIndustryAssociation,http://www.windpower.org/en/tour/econ/econ.htm

GeneralElectrics1.5MWWindSeries:1.5xteand1.5ste,http://www.gepower.com/prod_serv/products/wind_turbines/en/15mw/index.htm

LouisianaHB428(Act481),July12,2005.


Note: Thepeakcapacityof4.5MW for these threewind turbines,producedwhenwindspeedsexceed12m/s,comparestothe10,400horsepowermainengineequivalentto8MWofpoweronthehopperdredgeWHEELERoperatedbytheUSACE.Thesewindturbines,with82.5meterrotorlength,canproduce$400,000annually in electric power revenue based on 8 cents per kWh and 30% operating efficiency. At someadditionalcost,thesewindturbinescouldbeinstalledtoprovideelectricpowerrevenuetotheprojectwhenthepowerproducedisnotneededfordredgingoperations.

T7 UseMMStoregulateShipShoalquantitiestovariousprojectsneedingsediment

The proposed concept is to use theMMS to regulate the use of Ship Shoal sediments for use by variousprojects, in particular coastal barrier island restoration. Included in the idea is the thought to haveMMSevaluatetheactualquantitiesofavailablesedimentatShipShoalanddetermineappropriatelocationsforitsuse.

BACKGROUND: Following a request by theUSACE to be a CooperatingAgency in the LCABaratariaBasinBarrierShorelineRestoration,theMMShasbeenworkingwiththeUSACEandotherfederalandstatenaturalresourceagencies regarding theuseofShipShoalandother sandbodiesunder their jurisdiction foruseassandsources forcoastal restorationprojects. WorkingasaCooperatingAgency for theLCABaratariaBasinBarrierShorelineRestoration,theMMSdeterminedtheneedfor intensivecoordinationandmanagementofoffshoresandresourcesforuseincoastalLouisianarestorationprojects.InMay2003,Mr.BarryDruckerwiththe MMS established the Louisiana Sand Management Working Group (LASMWG) with the intent andpurposeofbringing together various federaland statenatural resourceagencies,aswellaspotential sandresourceusers (seeAppendix E). S. JeffressWilliams,U.S.Geological Survey (Coastal andMarineGeologyProgram,384WoodsHoleRd.,WoodsHole,MA 02543,email: [email protected])provideda compellingsummaryoftheproblemsandopportunitiesatthemeeting:

1. Needforlongtermsandrequirements:UseofoffshoresandfornourishmentandcoastalrestorationinLouisiana,aswellasmanyotherregions,haslongertermimplicationsthanjust20to30years.TheUSACEprojectsaretypicallyauthorizedfor50years.Forseveralprojectssuitableandeconomicalsandresourceshavenotbeenidentifiedfor50yearsofinitialfillandperiodicO&Mfills.Inmyjudgment,weneedlongertermplanningforcompilingsandneeds.Atminimum50years,100yearsisbest.

2. Need for sediment database/Seafloormaps: For Louisiana in particular, a great deal of data andinformationisavailablefromverydisparatesourcesonsandbodylocation,sandquality,andquantity.What isneeded isacomprehensivecomputerbasedsedimentdatabase.TheusSEABEDsystem isonestart in thisdirection,but itneeds furtherdevelopment to incorporate subbottomdata, i.e., cores,borings,andseismics.Also,atleastforpremiersandbodieslikeShipShoal,TigerShoal,etc.,weneedcompletemap coverageof the seafloorusingdigitalmosaic sidescanandmultibeam technologiesthathave recentlybecomeavailable.Suchbasemapsarecritical fornotonlyaccuratelydelineatingthe sandbodies,butalso important formappingessential fishhabitatsand infrastructure toavoid,suchaspipelines.

3. Permit streamlining: Plans for large scale barrier nourishment are well advanced in Louisiana,potentiallyrequiring~100CYmetersofsand.AnefficientpermittingprocessbytheUSACEandMMSneedstobeinplace.

4. Science studies/monitoring: Important questions arise on sediment transport processes associatedwithdredgingandnourishment,suchas:What is the traditionalengineering"closeoutdepth" fora


particularcoastandhowclosetoshorecanyoudredgewithoutexacerbatingerosionoftheadjacentcoast?WhatistheimportanceofebbtideshoalsedimentsfortheLouisianasedimentbudgetandcantheybeminedwithoutcausingdowndrifterosion?Whatistheoptimumspatialandtemporaldesignfordredgingsoastominimizeenvironmentalharm?Howlongdodredgeholesremainopen?Whatistheirshortandlongtermeffectsonmarinehabitats,waverefraction,etc.?

InMay2003, theMMSprovided in the FederalRegisteranotice toprepareamultiprojectenvironmentalassessment toevaluate thepotentialenvironmental impactsassociatedwith the removalof sand resourcesfrom Ship Shoal (see Appendix D).Meetings were conducted over the ensuing years withMMS fundingscientific efforts to investigate the potential impacts associatedwith removal of sand resources from ShipShoal.

IMPLICATIONSFORCREATIVE IDEA: TheMMS istheregulatoryagencywith jurisdictiontomanagetheShipShoalandotheroffshorefederalsandbodies.Theyhavebeenconductinginvestigationsoverthepastseveralyears. Therehavebeen several studies fundedby theMMS thathavedetermined theextentof sandandothermineralresourcesonShipShoal.TheMMShasfundedandwilllikelycontinuetofundstudiesregardingpotentialimpactsofremovingthesesandresourcesfromShipShoalonaquaticorganisms,aswellasonwavedynamics. However as described in the attachedminutes of theMay 2003meeting, theMMS does haveauthoritytomakedecisionsonsuitabilityorpriorityofsanduse;however,theMMSwouldpreferconsensusonthesedecisions.HencethecreationoftheLASMWG.

Mostrecently(seeemailbelow),Ms.StacieMerrittoftheMMSnotified intenttoconductameetingfortheLASMWG thisSummer inNewOrleans,Louisiana. The intentof themeeting istodiscuss issuesassociatedwithaccessingfederalsandandgravelresourcesforprojectsalongtheLouisianacoast.

-----Original Message----- From: Merritt, Stacie [mailto:[email protected]] Sent: Thursday, May 07, 2009 4:36 PM Subject: Louisiana Sand Management Working Group Meeting - Summer 2009 The Minerals Management Service, Marine Minerals Program is planning a meeting for the Louisiana Sand Management Working Group this Summer in New Orleans, Louisiana. The intent of the meeting is to discuss issues associated with accessing Federal sand and gravel resources for projects along the Louisiana coast. Below is a draft list of meeting topics: 1. A Marine Minerals Program Case Study: Pelican Island 2. Gulf of Mexico Significant OCS Sediment Resources NTL

(http://www.gomr.mms.gov/homepg/regulate/regs/ntls/2009NTLs/09-g04.pdf) 3. Need for OCS Mineral Resources 4. Geological and Geophysical (G&G) Authorization Requirements 5. Methodology and Potential for Submerged Cultural Resources in Borrow Pit

Areas We invite you to comment on the above list of topics and to suggest additional topics you would like covered at the meeting. Comments/suggestions should be sent to Stacie Merritt at [email protected] by June 5, 2009. We would also like you to provide input on the dates for the meeting. We are currently considering holding the meeting during the August 3 August


28, 2009 time period. Please go to the following link to enter your dates of availability. Make sure you scroll to the right to see all of the days. http://www.doodle.com/6rkmyvkiswfugkm6 If none of these days will work for you, please provide other dates for consideration. Dates of availability and proposed alternative meeting dates are due by June 5, 2009. Once we have an idea of how many people are interested in attending and how extensive is the list of topics, we will be able to determine the specifics on when it will be held and where. If you know of anyone who should be added to this mailing list (or deleted), please send their contact information to Stacie Merritt ([email protected]); their name will be added to future mail outs. We look forward to your participation in this meeting. Thanks, Stacie Stacie M. Merritt Marine Minerals Program Coordinator Minerals Management Service Coastal Program Section 504-736-3276

VEAlternativefollowup:

In June 2007,MMS sent a letter to all stakeholders (Federal, State, and other) requesting information onpotentialprojectsusingoutercontinentalshelf(OCS)sandandgravelresourcesinthenextfiveyears.BaseduponMMSresourcesandstakeholders'responsesregardingprojecttimelines,amaximumoftwoprojectsperquarterwerescheduled.

Most recently,MSSsentanother request inApril2009 toupdate thecalendar; responsesweredue June1,2009. Their intent is to publish the responses in the Federal Register in the third quarter of 2009. It isanticipatedthatMMSwillcontinuetoscheduleamaximumoftwoprojectsperquarter.

An email from StephanieM.GambinowithMMS is provided in the appendices of this report. The emailprovides informationregardingMMSmanagementofOCSdeposits,aswellasmaterialresourceevaluationsandstudiesspecifictoShipShoal.

T8 Considercoastalgeomorphicprocessesforsedimentplacement

TheconfigurationandmannerinwhichsedimentwillbeplacedonthebarrierislandswasnotpresentedintheApril2009FSMR. ItappearsthatthePDT is leaningtowardsplacementofmostsediment(sandontheGulfsideandmudonthebayside)onthedowncoastsideoftheislands,whichisthewesternendofeachisland.Thispreliminarydecision isapparentlybasedonthe factthatthe longshoretransportmovessediment fromeasttowest. Likewise, fromacrossshorestandpoint itdoesnotappearthatmuchconsiderationhasbeengivenyettohowthesedimentwouldbeplacedfromthebeachacrosstheduneandintothebackbaymarsh.


Itmightbepossibleto increasethe longevityoftheplacedsedimentbyconsideringthecoastalgeomorphicprocessesindevelopingand/orrefiningtheconfigurationandmannerofsedimentplacement.

Insteadofplacing sand in equal amounts along the entire lengthof the islandor in larger volumes at thewesternendofeach island,thePDTshouldconsiderconstructingtheeastendofeach islandwiderthanthewestend. Utilizing thisconfiguration for thebeach restorationandnourishmentactivitieswouldallow theeasternbeachareatoserveasa feederbeachprovidingasedimentsource tonourishdowncoast (western)beachesas the longshore transportmoves the sand fromeast towest. Prior to implementation,a coastalprocesses analysis should be conducted to determine the maximum beach width in each area to avoidoverbuilding thebeach in theeasternportionsofeach island. Anoverbuiltbeachcouldpush thesand intodeeperwatersand/orresultinoverlysteepbeachslopes,bothofwhichcouldincreasetherateoferosion.

Anotherconsideration intheplacementofsedimentfor islandrestoration istheaspectratioofeachbarrierisland.Theaspectratioisthelengthofeachislanddividedbythewidthanditcanbecalculatedasameanorat regular intervals (e.g.,everyquartermile)along theentire lengthofeach island. Therehasbeen someresearchconductedtoestimatetheoptimumaspectratioforthebarrier islandsandthis informationshouldbeconsideredinthedevelopmentofsedimentplacementconfigurations(volumesandlocations).

T9 Utilizesandrecycling/backpassingforbarrierislandnourishment

Beach restoration and beach nourishment are presented in the April 2009 FSMR as two managementmeasures thatwill be carried forward for future consideration in the formulation of project alternatives.Beachrestoration isdefined in theFSMRas the (initial)placementofbeachsuitablesediment (sand)withinthe beach profile from the dune out to the depth of closure,while beach nourishment is defined as theperiodicplacementofsandinthesamelocation.Beachrestorationbasicallyrestorestheshorelineandbeachtohistorical conditions,whilebeachnourishment keepspacewith future erosion tomaintain the restoredcondition. Ongoing beach nourishment activitieswill require the identification and dredging of additionalsourcesofsandinthefuture.Basedonexistinginformationanddata,sandisalreadylimitedinavailabilityandthere isa lotofdemand for that sand for thisprojectaswellasotherprojects in the LCA. Therefore, theretentionandefficientuseofexistingandfuturesandresourceswillbeanimportantfactorincosteffectivelymeetingprojectobjectives.

One way to make more efficient use of existing and future sand resources is to utilize sandrecycling/backpassing to replace and/or augment beach nourishment activities. In the Terrabonne BarrierIslands,thenetlongshoretransportisfromeasttowest,meaningthatsandisdrivenbythewavesfromeasttowest.Sandrecyclingwouldconsistofdredgingsandatthewesternendofthebarrierislandsandplacingiton the eastern end. This would help reduce the quantity of new sand needed for future nourishmentactivities.Theeffectivenessofsandrecyclingcanbeimprovedthroughtheconstructionofterminalgroinsorbreakwatersatthedowncoastendofthebarrierislandstocaptureasmuchsandaspossiblebeforeitislosttothebayareaand/orGulfofMexico.Priortoimplementation,coastalprocessesanalysesshouldbeconductedtomakesurethatsandfromanupcoastisland(i.e.,totheeast)isnotprovidingasubstantialsourceofsandtoadowncoastisland,otherwisethesandrecyclingprogrammightresultinincreasederosiontothedowncoastbarrier island. Sand recyclinghasbeenusedwith success alongPeninsulaBeach,which is located in LongBeach,California.


T10 Fixbarrierislandsintheircurrentlocation,eliminating/minimizingislandrollover,byincorporatingahardcore(e.g.,buriedsandfilledGeotubes,revetments)orallowsurfacearmoring(e.g.,revetments,rock,concrete)

The natural geomorphic development of barrier islands is to allow them to rolloverwhere the dune fieldprogresses landward overriding the backmarsh as the beach face erodes. This is currently the preferreddesignaspresentedby theUSACEPDT. Inorder forthisapproachtobesuccessful,periodicrenourishment(typicallyeveryfiveyears) isrequiredoverthe50year lifeoftheprojecttomaintainboththebarrier islandand thebackmarsh. However, thecurrentprojectplanandbudgetonlyallows fora single renourishmentafteraboutfiveyears,whichmeansthesustainabilityoftheprojectisindoubt.

Analternativeapproachistofixtheislandsinplaceandminimizetheamountofrenourishmentrequired.Thisisnotanaturalgeomorphicprocessforbarrierislandsasitlimitsrolloverandmigrationofthebarrierislandlandward. However, thereareagencies in the state,aswellasmembersof thegeneralpublic,whowouldprefer this approach as amore positivemeans of providing storm surge and salinity intrusion protection.Fixing the location of the islands with a corresponding reduction of renourishment needs may improvesustainabilitywithintheavailablebudgetfortheproject.Itwouldalsoreducetheamountofmaterialneeded,whichisaconsiderablegeneralprojectconcern.

Onealternativeinstallsaburiedhardscapethatdrawsalineinthesandontheshoreline.ThesandfilledGeotube (usingsandalreadyearmarked forbeachanddune restoration)would resisterosionofsandalongwithstormsurgerelatedbreaches inamorecosteffectivemannerthan,say,offshorebreakwaters. InmostcasestheseGeotubescanreplacetheoffshorebreakwaters,orbeusedintandemwiththebreakwaters(suchasinvertedbreakwatersproposedabove)incriticalareas.

SincetheGeotubesarenotexposedmostofthetime,theywillnotexperiencedeteriorationfromsunlightorvandalism. Ifdamage to theGeotubesoccurs from storm surgeactivity, they canbe replacedor repaired.ErosionofthesandinfrontoftheGeotubesandontopwilllikelyoccurovertimerequiringrenourishmentofthedunesapproximatelyeverytenyears.Asketchofthisconceptisshownbelow:

InlieuofGeotubes,otherhardenedmaterialssuchasrevetmentsorrockcanbeburiedinthecoretoincreasethe hardness of the island. Further, surface hardening can be considered through the use of surfacerevetments, concrete, or rock; however, this approach may not be preferred over the hardened coreconceptasitwouldtakeawayfromthesandbeachsurfacethatmaybepreferrednestingareasforbirds.Inaddition,surfacehardeningwouldbeconsideredtobe lessaestheticthanexposedsandsurfaces,andwouldbelesscapableofsupportingstabilizingvegetation.


T11 Constructgroinsand/orbreakwaterswithprefilledsediment

Theuseofgroinsandbreakwaterstotrapsandonthebarrierislandswereidentifiedaspotentialmanagementmeasurestobecarriedforwardthroughtheplanformulationphase. Basedonthe informationpresented intheApril2009FSMR,itappearsthatgroinsandbreakwaterswouldbeimplementedwithouttheuseofprefill.The implementationofgroinsandbreakwaterswithoutprefillcan leadtoerosionofadjacentshorelinesandbeachesasindicatedintheFSMR.Thiserosioniscausedbythetrapping(orretention)ofsandinthefilletofthegroins,aswellasthesalient(ortomboloifthesalienttouchestheshoreline)ofthebreakwaters.

The addition of prefill should be considered to address the potential impact of erosion attributed to theimplementationofgroinsandbreakwaters.Forgroins,theuseofprefillwouldentailestimatingthevolumeofsandthatwouldbetrappedinthefilletandthenplacingthisvolumeofsandinthefilletaspartoftheinitialgroinconstructionproject. Inthecaseofthebreakwaters,theuseofprefillwouldconsistofestimatingthevolumeofsandthatwouldbetrappedinthesalientandthenplacingthatvolumeofsandinthesalientaspartof the initialbreakwater constructionproject. Theuseofprefillmitigates for impacts toadjacentbeacheswhile the retention structure (i.e., groin or breakwater) provides a wider, more stable beach. Prior toimplementationofprefill forabreakwater,a coastalprocesses analysis shouldbe conducted toassess thepotentialimpactofthesalientitselfonlongshoretransport.

T12 Constructnewbarrierislandchainclosertonewshoreline

Thereishighprobabilitythatmaintainingtheexistingbarrierislandsbeyondthe50yearplanninghorizonwillnotbepossibledueprimarilytoincreasingratesofsealevelrise,futuresubsidence,andresourcesconstraints(e.g.,sedimentsupplyandfunding).Giventhevalueofthehabitatontheislands,aswellastheimportantrolethese islandsplay inprotectingbayside resources, it stillmakes sense toexpend resources in restoringandmaintainingtheislandsfromnowandintotheimmediatefuture(e.g.,50years).However,italsomakessensetobeginthinkingnowaboutthelongtermsustainabilityoftheentireecosystemintheLCA.

It issuggestedthatconsiderationbegiventothedesignandconstructionofanewbarrier islandchain. Thiswouldincludetheidentificationofanewfallbackshorelinethatwouldbeusedtoguidethelocationofthenewbarrier islandchain. Thisnewshorelineandbarrier islandchainwouldformthesecond lineofdefense,with the first lineofdefensebeing the restorationandprotectionof theexistingbarrier islands. Thenewbarrier islandchaincouldbeconstructed inareasoftheexistingLCAthatarerelativelyhigh inelevationandfree of oil and gaswells and pipelines tominimize construction costs associatedwith fill placement andconstruction access. In addition, this strategy could be implemented through an adaptive managementframeworksuchthatlessonslearnedfromrestorationandmaintenanceoftheexistingbarrierislandscouldbeusedtoimprovethedesign,construction,andmaintenanceofthenewbarrierislandchain.

T13 Establishanenvironmentaldredgingfleet

Theamountofsedimentneeded to renourish thebarrier islandsystemwill farexceed theavailabledredgefleet inandbeyondtheregion. Whileprivate industrywillrespondtothisneedbymanufacturingadditionaldredgesasprojectsprogress,itislikelythatsuchplantdevelopmentwillseverelylagprojectdemand.Privateindustrywillnot likelyproducemorethan isneededatanygivenperiod,astheywillperceiveariskofoversupplying intermediate need. Such projected constant shortageswill likely limit bid completion and raisepricessubstantially.


Apossiblemeansofavoidingthisproblemmaybegovernmentpartnershipswithprivateindustrytofabricatenewdredgesinadvanceofindividualprojectneed.Forexample,thegovernmentcouldbuildtheneededfleetand lease theequipment to industry; thegovernmentcould finance industry tobuild their fleet;or industrycould build the fleet on their own and lease equipment to the government. There are a number oflease/purchase and other innovative procurement options that balance risk and optimize financialadvantagesbetweenthegovernmentandindustry.Ingeneral,thegovernmentcansecurecapitalatrelativelylow cost and industry can take tax advantages of ownership via depreciation deduction. Such advancefabricationofdredgescouldhelpinachievingadequateresourcesupplytomeetprojecteddemand.

T14 Prioritizeprojectcomponentsbasedonmarshlossfactors

ThePDTindicatedthatsometypeofsystemwouldbeneededtoprioritizerestorationactivities.However,itdoesnotappearthatsuchasystemwasdevelopedorappliedduringpreparationoftheinformationcontainedintheFSMR.ThePDTwasaskedifanestimatehadbeendevelopedthatrepresentsthepercentageofmarshloss due to the various causes of erosion. For example, howmuch of every 100 acres ofmarsh loss isattributed to sea level rise, fluidwithdrawalinduced subsidence, sediment compactioninduced subsidence,windwave erosion, storminduced erosion, vegetation loss attributed to salinity changes, and herbivoreactivity. Note that a cursory review of the figure in Attachment F of the April 2009 FSMR suggests arelationship between oil and gas extraction (as represented by oil and gas wells) and marsh loss (asrepresentedbyopenwaterareas).Itisimportanttodevelopanestimateoftheimportanceofthesevariouslossfactorsbecauseaprimarystatedobjectiveofthebarrierislandrestorationistoprotectandpreservethemarsh to the north of the islands. If sea level rise and fluidinduced subsidence are of equal or greaterimportance thanwindwaveerosionand storminducederosion, then restorationof thebarrier islandsmaynotachievethisobjective.

Oneway to address this issuewould be to conduct an analysis to determine the amount ofmarsh lossattributed to sea level rise, fluidwithdrawalinduced subsidence, sediment compactioninduced subsidence,windwave erosion, storminduced erosion, vegetation loss attributed to salinity changes, and herbivoreactivity. Theresultsof thisanalysiscould thenbeusedtoprioritizeprojectcomponents,therebygivingthePDTaplanningtoolfortheprioritizationtaskthattheywillhavetoundertake.Theresultsmightalsosuggestthat it isnotpossible tomeet someof theprojectobjectivesor that theobjectives themselvesneed tobeprioritizedinordertoselecttheappropriaterestorationactivities.Concernaboutthepossiblefindingsofthisanalysis shouldnotbeusedasa reasonnot to conduct it since the resultswillmerely inform thedecisionmaking process. For example, even if the results indicate that sea level and/or subsidence are primarycontributorstomarshloss,itdoesnotmeanthatbarrierislandrestorationshouldnotbeimplemented,rather,itmeans that barrier island restorationwould probably not be effective inmeeting the project objectiverelatedtomarshprotectionfromwindwaveerosionandstorminducederosion.

T15 AddPlanStrategythataddresseshabitatneedsinexcessofbudgetarylimitations

ThePlanStrategies identifiedfortheprojectare intendedtoproduceafullspectrumofalternativeplansasrequired by National Environmental Policy Act (NEPA) and USACE planning guidance in ER 11052100.AlternativePlanStrategiesweredesignedtobesignificantlydifferentfromoneanotherandtorepresenttheentirerangeofsolutionstoidentifiedproblemswithinthestudyarea.ThisVEalternativeconceptisintendedasachecktothePDTthatPlanStrategyE,increaseofcurrentconfigurationandfunctionalgeomorphology,bethePlanStrategythataddresseshabitatneedsaboveandbeyondthebudgetarylimitationssetbytheprojectauthorization. DuringtheNEPAalternativeevaluationprocess,thisconsideration isneededregardless ifthefundswillbeavailabletoevermakethealternativefeasible. IfPlanStrategyE isnot intendedtosatisfythis


partofthealternativeevaluation,suggestdevelopinganadditionalPlanStrategythatdoesaddressthebestcasescenarioregardinghabitatcreationandsustainment.

T16 Implementoil/gasindustryoutreachprogramregardingfuturesedimentmanagement

The PDT indicated that the oil/gas industry (industry)might redistribute sediment placed on the islandsfollowingrestorationactivities.Theindustryhasalongstandingpracticeofredistributingsedimenttoprotectoil/gas infrastructure. Forexample, the industry redistributes sedimentviadredging toburypipelines thathavebecomeexposedfollowingstormandhurricaneactivity.Consequently,thePDTexpressedconcernthatthe industry would utilize the newly placed sediment for this purpose upon completion of restorationactivities,therebydecreasingtheeffectivenessofrestorationactivitiesandunderminingprojectsuccess.

Anoutreachprogramcouldbe implementedtoproactivelyaddressthis issue. Theoutreachprogramwouldexplain the various restoration components to the industry. Itwould include a description of the naturalsedimentprocessesandhowthoseprocesseswouldbenefitthenaturalhabitatandresources,aswellashowthose processeswould benefit the industry. A description of acceptable sedimentmanagement practiceswouldbe included in theoutreachprogram tominimizenegativepracticesandmaximizepositivepracticessince itmight be possible to work with the industry to helpmaintain and/or improve the islands uponcompletionof restoration activities. Finally, theoutreach programwouldhave tobedeveloped in carefulconsideration of the target group that is to receive the information tomake sure the right people in theindustryaregetting themessageandthat it is tailoredtothosepeople. Thiswillhelpensurethattherightmessageisgettingtotherightpeople.

T17 Changethetermnonstructuralinprojectdocumentstosoftstructural

The project documents use the following definition of terms: A management measure is a feature (astructuralelementthatrequiresconstructionorassemblyonsite)oranactivity(anonstructuralaction)thatcanbecombinedwithothermanagementmeasurestoformalternativeplans. Thetermnonstructural iscommonlyusedinUSACEfloodcontrolandhurricaneprotectionprojects.Ithasaveryspecificmeaningthatincludesoptionssuchasfloodproofingproperty,raisingbuildingsabovefloodelevations,purchasingpropertyand/orrelocatingorremovingthepropertyfromtheareaofrisk,andprohibitionoffurtherdevelopment inareasofrisk.However,forthisproject,thetermistorefertorestorationactivitiesthatinclude:

Dunerestoration

Marshcreation

Beachrestoration

Beachnourishment

Subtidalsedimentplacement

Additionofsedimentintonearshoreenvironmenttosupplementlittoraldrift

Beachclosure

Smallmarshislandconstructiononbaysideforbirdhabitat

Vegetativeplanting

Herbivorycontrol


Biologicalbioengineeredoysterreefs

Spitcreation

Canalbackfilling

Inordertoavoidconfusionwithagenerallyaccepteddefinition,theVEteamrecommendsthatthetermnonstructural,asusedintheprojectdocuments,bechangedtosoftstructural.


MULTIPURPOSEOPERATIONOFHOUMANAVIGATIONLOCK

H1 Optimize holistic system by balancing HNC flow rate capacity with gate and lock design andoperationplan

TheHNClockandfloodgatewereplannedoveradecadeago.ThepossibleadditionofayearroundsignificantfreshwaterflowintotheHNCfromtheproposedAtchafalayaRiverDiversionProjectwouldsignificantlyaffecttheoperationofthelockandfloodgateandperhapsevenwarrantreconsiderationofthefacilitydesign.

The lockandfloodgatehavemultiplepurposesandfunctions(referenceCoastal ImpactAssistanceProgramApplicationHoumaNavigationCanalLock,May22,2006;TerrebonneLeveeConservationDistrict,includedasAppendixA).Firstandforemostisprovidingabarriertotidal(hurricane)floodingasanintegralpartoftheproposedMorganza to theGulf leveesystem. Thesecond function is toblockexcessivesaltwater intrusionintothebasin. Highsaltwater levelsadverselyaffectmarshhabitatandpotablewatersupplyfortheCityofHouma. Asresultofprovidingabarrier intheHNC,accommodationstominimize impactstonavigationareincorporatedinthedesignoftheclosurefacility.A250footwide(200feetwidepriortorecentchange)gatewillallowsafepassageofoilrigcomponentsand the110foot lockwouldallownormalvessel trafficduringprolongedperiodsofclosure.

Therequiredoperatingfrequencyanddurationofthe110footlockmaybegreatlyaffectedbytheamountofwater(andconsistencyofthissupply)thattheproposedAtchafalayaRiverDiversionProjectcanproduce.Theveryneedforalockshouldalsobereevaluatedandbalancedwiththeformulationofthisproject.

Itmay be determined that adequate freshwater flow can be supplied to theHNC, negating the need forsaltwaterintrusiongate/lockclosure.Thiscouldminimizelockoperationfrequencytoanaverageof20daysperyear(usuallynoncontinuous)duetohistoricalfloodevents.Thequestionarisesastowhetherornotsuchminimalclosure timewarrants theneed forvesselpassageduringsucheventsas therearealternate (albeitlengthy)alternativeroutestotheGulfofMexico.

On the other hand, significant freshwater flow in the HNCmay be distributed out from the channel intoadjacentmarsh ifarelativelysmallhydraulichead isartificiallymaintainedbymeansofclosingthegateandlock.Thiswouldrequirealengthy(perhapsfulltime,allthetime)operationofthelock.

The recommendation is to budget for fulltime lock operation (about $1.2million per year) and integrateAtchafalayaRiverDiversionalternativeselectionwithHNC lockoperation,design,andperhapsnecessity. Ifthis isdone, itmaybedetermined thattheAtchafalayaRiverDiversionmaybeefficientlymaximizedwitharesulting minimization of lock total life cycle cost. This may indicate that the set diversion project preauthorization amount of $221 million be exceeded to achieve overall system costeffectiveness with areductioninHNCLocklifecyclecosts.Thiscouldbecomplicatedgiventwoseparatefundingauthorizations.

Itshouldbenoted that theHNC lockand floodgatecomplex ispartof theMorganza to theGulf,HurricaneProtection Project. The parent project authorization is currently in abeyance pending approval of a PostAuthorizationChange(PAC)report.Thisreportisrequiredduetoanofficialprojectcostincreaseinexcessof20%.ThePACiscurrentlybeingdeveloped,butitsscopeislimitedtoonlylevelofriskreduction(leveeandstructure height) and not broader project parameters.Given the abovementioned significant existing andpossiblefutureconditionschangesrelativetoplanformulationcriteriaofadecadeago,theentiredesignof


the proposed lock and floodgate should be reevaluated. A summary list several significant outstandingquestionspertinenttothelockandgatecomplexisasfollows:

WouldtheintroductionofasignificantlyhigherflowoffreshwaterdownHNCnegatetheneedtoprovideabarrierfornonfloodeventsaltwaterintrusion?

If higher flows are introduced downHNC,would closure result in beneficial distribution of freshwaterupstreamofthefacility(additionalpurpose/reasonforalockstructure)?

If soon to be published USACEsanctioned predictions of net sea level rise is faster and higher thanpreviously anticipated,would it then be prudent to build a singlewide (250 foot) lock versus awidefloodgateandsmaller(110foot)lockcombination?

The localsponsorapparentlyhasrequestedapermittoconstructatemporarystandalonebargegateaspartoftheirleveeconstructionplan.Canthisserveforalongerperiodoftimeanddeferconstructionofanexpensivesectorgate?Also,ifasinglegateclosureis(now)apparentlyacceptabletothelocaloilandgasindustry,whydoesthefederalplan(still)requirealockandgatecombination?

Doesthecostestimatereflect,andisitconsistentwith,ongoingconstructionoflargesectorgatesfortheIHNCEastClosureandforthecurrentdesignoftheGIWWWestClosureComplex?

H2 Develop a set of guidelines for when gate will be shut and install monitors and controls toautomaticallyclosegate

ThefloodgateontheHNCisproposedtobeclosedforfloodandsalinitycontrol.Ifthegateisclosed,marinetrafficwillberequiredtousethelock,thusresultinginpossibledelaystonavigation.

GiventheimportanceofthegatetosafenavigationontheHNCaswellastothemarshlands,andthatthesetwo factorsmay compete against one another regarding whether the gate should be closed or not, anautomaticsystemshouldbeconsidered thatwouldclose thegateatspecific,predetermined levelsof tidalsurge, salinity, and canal flow. Thiswould serve to eliminate the possibility of one function of the gatesupersedingtheothers.

H3 InstallflowcontrolonHNCcutsintothemarsh

TheCentralLakeBoudreauxAreaproblemsandopportunities includemajorhydrologicalterationsthroughthepresenceoftheGIWWandtheHNC.However,oneoftheprimaryconcernswithinthisstudyunit isthealteredhydrology anddistributionof freshwater and sediment. Freshwater and sediment that reaches theCentralStudyAreahaspoordeliverytothewetlands.IftheprojectincreasesfreshwaterflowdowntheHNCandcutsaremadethroughspoilbanks, itmaybeprudenttoalso installflowcontrolattheseopenings. Byinstallingwickertypegatesorotherbackflowpreventer,thefreshwaterwouldnotquicklydrainbackintotheHNCas flowdiminishes. Thisalternativewouldallowcontrolof freshwaterreturning into theHNCas flowssubside in that channel. Freshwater would then be available to drain out slowly through intermarshpathways.


H4 Configureproposed250footfloodgatesuchthatanadditionalgatecouldbeaddedinthefutureinordertoupgradetoalock

If significant sea level risebecomes a reality,HNC closurewillbe required throughout the year. Thismaynegatetheabilitytosafelypassplatformstructuresthroughasinglefloodgate. Itthenmaybewarrantedtoupgrade theproposed250foot floodgate toa full lockwith theadditionofa secondgate. Placementandconfigurationof the initial floodgate should accommodate such apossible futuremodification. Navigationapproachreacheswouldbeaprimaryfactortoconsider.

H5 Extendutilizationoftemporarybargegateanddeferconstructionofnewsectorgate

Thestateandlocalleveedistricthasplanstoconstructatemporary250footbargegateaswellasasystemwidereducedheight levee. Theheightofthegatewouldnotprovidedesired0.01annualstormprobabilitycontainment, but still be on the order of 0.02 to 0.04. The subsequent federal projectwill increase thisprotection to the0.01 level. However,a very costly component, the250foot floodgate (new sectorgate)couldbeleftasalastorderofconstructionorevenbedeferredforseveralyears.Theprotectionobtainedbythetemporarygatewouldonlyallowwaveoverwashduringpeakhurricanehoursandthevaststorageoftheprotected area could easily accommodate such inflowwithout any significant property damage. Itwouldtherefore appear prudent to extend the service of the temporary floodgate until major maintenance isneeded.

An estimated breakout cost for the 250foot floodgate fromURS TaskOrder 5,May 2008, is about $150million.Estimatedmajormaintenancecostwouldbeabout$5millionintenyears.Annualinterestsavingsoffirst cost and tenyear maintenance costs at the current federal discount rate of 45/8% would beapproximately$7millionperyearofdeferral.

H6 Considerusingafloatablebargegateinlieuofasectorgate

Intheinitialprojectplanning10+yearsago,thepremisewasthata200footwidesectorgatewasafavorablechoiceversusabargetypegategiveneasierandfasteroperation.VEstudiesthen,andsincethattime,havechallenged thispremise given theunprovenperformanceof sucha large sectorgate. Majormaintenance,whenthegatemustberemoved,isasignificantconcernforlargesectorgates.TheUSACEhaschosena150footcomplementarybargegatedesignfortheeastGIWWclosurecurrentunderdesignbuildconstruction.Itisstillbelievedthatafloatingbargegatemaybemoreappropriate,bothininitialcostandlongtermcosts,forthenow250footHNCgate.SeveralconceptualfloatingbargegatedesignsareillustratedinAppendixB.

H7 Constructconcretesectorgatesorutilizeothermaintenancefavorablematerials

The standard gatematerial is steel protected by sacrificial anodes for corrosion resistance. The USACEconductedanextensivevalueanalysisassessmentoftheuseofdifferingmaterialstoconstructgates(sector,miter,tainter)alongwithtechniquestoreducecorrosion. Thisstudywas initiatedaftertherecognitionthattypicalsteelgateserodedeasilyandweredifficultandexpensivetorepairandmaintain. TheresultsofthisstudywerepublishedonAugust13,2004 inavalueengineeringreportentitledImprovingLifeCycleCostsofConstruction/Operations/MaintenanceofGateStructures.ItisworthnotingthatSouthFloridaWaterDistrictisnowutilizingallstainlesssteelgates. Presentedbelowaresomeof theadvantagesanddisadvantagesofseveraldifferentgatematerials:


ADVANTAGES

StainlessSteelGates:

Stainlesssteelhasexcellentcorrosionresistance.

Stainlesssteelgateswouldnotneedtobepainted.

Themaintenancecyclewouldbegreatlyincreased.

Thedurationofthemaintenanceeventwouldbereduced.

Potentiallylightergates.

AluminumGates:

Aluminumhasexcellentcorrosionresistance.

Aluminumgateswouldnotneedtobepainted.

Themaintenancecyclewouldbegreatlyincreased.

Thedurationofthemaintenanceeventwouldbereduced.

Potentiallylightergates.

ConcreteGates:

Concretedoesnothavethesamecorrosionproblemsthatsteelhas.

Concretegateswouldnotneedtobemaintainedasoftenassteelgates.

Concretecanbedesignedtobeimpactresistant.

Lightweight concrete can be used in conjunction with normal weight concrete to lighten the overallweight.

Compartmentscanbecasttoincreasebuoyancy.

Leftandrightgateswouldusethesameformwork.

DISADVANTAGES

StainlessSteelGates:

Stainlesssteelhasthesamestiffnessasstructuralsteel.

Stainlesssteelismoredifficulttoweldthanstructuralsteel.

Stainlesssteelmaterialcostsmuchmorethanstructuralsteel(aboutthreetimesthecostonaperweightbasis).

Potentialcorrosionissuesatconnectionpoints(hinge,pintle,drivemechanism).

AluminumGates:

Aluminumisonly33%asstiffassteel.


Weldedaluminumisabout66%thestrengthofsteel.

Aluminumisdifficulttoweld.

Aluminumcostsmuchmorethanstructuralsteel(abouttwotimesthecostonaperweightbasis).

Aluminumdoesnothaveanendurancelimit,makingfatigueaconcern.

Potentialincreasedcorrosionofattachedhardware(hinge,drivemechanism,pintle).

ConcreteGates:

Concretecancrack;crackswouldeliminatewatertightproperties.

Replacementofindividualmemberswouldbedifficult.

Reinforcingsteelmaycorrodeundercertainconditions(epoxycoatedbarsshouldbeused).

Concretestructuresaretypicallyheavierthansteelstructures.

Attachmentofhardwaremaypresentproblems.

Spreaderbarneededforlifting.

Requiredfloorofgatestructuremayadverselyaffectoperationproblemscausedbydebris.

Longtermdataonfiberreinforcedplastic(FRP)reinforcingbarsisonlyavailableforroughlytenyears.

Lock and floodgates, constructed of steel, require maintenance to address issues that include corrosion(rusting, pitting), seal deterioration, cracking, and impact damage. Each gate is unique in dimension andweight to the lock or floodgate it serves. Themaintenance cycle is usually about every 10 to 12 years;however, this timeframe isoftendelayedbybudgetaryconstraints,oracceleratedby some formof impactdamage thatmakes a gate inoperable. For a lock, a completemaintenance event is usually done in twoconsecutiveyears,whereone setofgateswillbepulled/rehabilitatedatanoptimal timeof theyear, thenrepeatedfortheothersetofgatesthefollowingyear. Atypicalexampleofamaintenancecycle isthePortAllen Lockwhere completionof the cyclewould take about90days,buthasbeen accelerated to45daysthroughtheuseofasparesetofgates.Thelengthofclosureofthelockhasbeenabout6to9daystotaltofacilitatemaintenance. Depending on location, amaintenance cycle closure can impact users at a cost inexcess of $6million (preHurricane Katrina). Tables 1 and 2 illustrate the economic impact to navigationcurrent(2004)maintenancecycleshaveatitsmostsignificantlocation,CalcasieuLock,andwhereleasteffectsareencountered,HarveyLock.


Cost of 8 Day Closure at Calcasieu Lock and Harvey Lock

Calcasieu Lock Harvey Lock

Year 2001 Year 2001Tons 38,680,000 Tons 2,094,000

8 Days of Avg Delay/Tow (hrs) 0.98Tons 847,781

Algiers LockCost of WaitingPer Hr/Ton 0.08 Year 2001

Tons 22,879,000 Cost of 8 Day Closure 6,510,957 Avg Delay/Tow (hrs) 3.37(Use 4 Day Avgor 96 hrs) Algiers Lock with Harvey Traffic 24,973,000

Estimated Avg Delayper Tow if Harvey Trafficdiverts to Algiers Lock 7.13

Annual Cost of Delay Without Diversion 8,220,298 Annual Cost of Delay With Diversion 14,240,079

Incremental Annual Cost of Diversion 6,019,781

Incremental 8 Day Cost of Diversion 131,940

Table1:Costof8DayClosure


PRESENT WORTH OF ECONOMIC IMPACT OF MAJOR MAINTENANCE CLOSURES @ CALCASIEU AND HARVEY LOCKS

Present Worth Calcasieu Lock Harvey Lock

Factor 6,511,000$ 132,000$ Year @ 5.5% per maint. event per maint. event

10 0.585 3,808,935$ 77,220$ 11 0.555 3,613,605$ 73,260$ 20 0.343 2,233,273$ 45,276$ 21 0.325 2,116,075$ 42,900$ 30 0.201 1,308,711$ 26,532$ 31 0.19 1,237,090$ 25,080$ 40 0.118 768,298$ 15,576$ 41 0.112 729,232$ 14,784$

Total: 15,815,219$ 320,628$

Present Worth of Impact to Navigation

Table2:PresentWorthofNavigationalBenefits

Representatives from the USACE report that several significant components tomaintenance exist. Theseincludepullingthegate,whichrequiresasubstantialnumberand/orcapacityofcranesaseachgatecanweighfrom 30 to 200 tons, and sand blasting and painting, which comprise the greatest amount ofmaintenance/restoration time. They further report that sector gates are more durable and exhibit lessstructuraldeterioration thanmitergates.Theseobservationsmaybe the reason thatallcurrentlyproposednewcontrolstructuresarebeingplannedordesignedwithsectorgates.

Theresultsofthe2004VEStudymaybesummarizedasfollows:

The USACE NewOrleans is currently very successful in operating andmaintaining their gate and lockstructures. Current practices allow for virtually uninterrupted service for generally 10 years ormorebetweenmajormaintenance cycles. However, the cost of performingmajormaintenance andmoreimportantly,theeconomicimpacttonavigationwhencriticalstructuresaretemporarilyputoutofservice,aresignificant.Thereisthepotentialthatevenmarginalimprovementsmayproducelargebenefits.

The 2004VE Study produced a number of recommendations that appear to be economically justified.Most require additional upfront investment cost thatwill lengthen the time between requiredmajormaintenanceevents.Proposalsaddressbothchangesthatcanbeimmediatelyimplementedatrelativelylowcost(addcathodicprotection,changecoatingsystem)andchangestofuturegatedesignandmaterialselection(stainlesssteel,aluminum,concrete,etc.).

Anumberoftherecommendationscitefieldprovendesign/maintenancepracticesthatshouldhaveahighlevel of confidence for successful implementation. Others suggest investigating something completelynew,andsomedegreeoffurtherresearch,developmentandanalysismustbeperformedpriortofullscaleapplication.

Mostoftherecommendationsarecosteffectivepurelyonthebasisofpotentialdirectmaintenancecostsavings thatmaybe realizedby lengthening the timebetween requiredmajormaintenance events. It


shouldbeparticularlynotedthatthepotentialeconomicbenefitsforimprovingmaintenancecyclelengthatlocationswheremaximummarinetrafficimpactsoccurareenormous.Maximizingmajormaintenancecycles at these locationswill be highly leveraged, justifying even very high first cost investment. Forexample,theuseofstainlesssteelgatesappearstoproduceabenefittocostratioofover5:1 ifused inlieuofregularstructuralsteelatsuchacriticallocation.PleaserefertothethreeSummaryofAlternativestableson the followingpages;butnote that thecosts shownarepreHurricaneKatrinaestimates. Theoverallbenefitshouldstillremain.

In considering the recommendations of the 2004 VE Report,USACENewOrleans should include suchfactorsasavailablefunds,shortandlongtermimplementation,andrelativecriticalityofstructureserviceinfurtherdevelopingandprioritizingfuturemaintenanceactions.


SUMMARYOFALTERNATIVES

RANKEDACCORDINGTOPOTENTIALLIFECYCLECOSTSAVINGSNOTINCLUDINGBENEFITSTONAVIGATION(PREHURRICANEKATRINA)

AlternativeNumber

AlternativeTitle

TotalEstimatedPresentWorthofLifeCycleCostSavingsNotIncludingImpactstoNavigation

SET1 ChangestoMaintenance

4 Usemetalflamesprayedcoatinginsteadofpaint $1,200,000

2 Use100%solidscoatingforpaint $600,000

1 Usegalvanicanodecathodicprotectioninadditiontopaint $500,000

3A Applyceramicorcementitiouscoatingtosteelexistinggates $200,000

6A Replaceexistinggateswithstainlesssteel ($600,000)

SET2 AlternativeMaterialsandDesign

8A Build sector gates out of concrete; pretension or posttensionconcrete

$1,600,000

8B Build sector gates out of concrete; pretension or posttensionconcrete,useFRPreinforcementinsteadofsteel

$1,400,000

7 Buildgatesoutofaluminum $1,100,000

9 BuildFRPgates $300,000

5 Use tubular members where possible; eliminate/reduce complexcornersdesigningforcorrosionresistance

$250,000

3B Applyceramicorcementitiouscoatingtosteelnewgates $50,000

6B Buildgatesoutofstainlesssteel ($125,000)

10 Build sector gates out of ultra high molecular weight polyethylene(UHMWPE) plastic or cast/molded urethane or polyethylene, orequivalent;withstainlesssteelwearingedgesandcorners

($4,000,000)


AlternativeNumber

AlternativeTitle

TotalEstimatedPresentWorthofLifeCycleCostSavingsIncludingMinimumImpactstoNavigation



2 Use100%solidscoatingforpaint $800,000

1 Usegalvanicanodecathodicprotectioninadditiontopaint $700,000

3A Applyceramicorcementitiouscoatingtosteelexistinggates $250,000

6A Replaceexistinggateswithstainlesssteel ($300,000)


8A Buildsectorgatesoutofconcrete;pretensionorposttensionconcrete $1,900,000


$1,600,000


9 BuildFRPgates $600,000


$300,000

6B Buildgatesoutofstainlesssteel $125,000

3B Applyceramicorcementitiouscoatingtosteelnewgates $100,000

10 BuildsectorgatesoutofUHMWPEplasticorcast/moldedurethaneorpolyethylene, or equivalent; with stainless steel wearing edges andcorners

($3,600,000)


AlternativeNumber

AlternativeTitle

TotalEstimatedPresentWorthofLifeCycleCostSavingsIncludingMaximumImpactstoNavigation


6A Replaceexistinggateswithstainlesssteel $12,000,000

1 Usegalvanicanodecathodicprotectioninadditiontopaint $11,100,000


2 Use100%solidscoatingforpaint $7,100,000

3A Applyceramicorcementitiouscoatingtosteelexistinggates $3,000,000


8A Buildsectorgatesoutofconcrete;pretensionorposttensionconcrete $14,900,000


$14,600,000


9 BuildFRPgates $12,800,000

6B Buildgatesoutofstainlesssteel $12,400,000

10 BuildsectorgatesoutofUHMWPEplasticorcast/moldedurethaneorpolyethylene, or equivalent; with stainless steel wearing edges andcorners

$11,900,000

3B Applyceramicorcementitiouscoatingtosteelnewgates $2,800,000


$1,900,000

The primary cost benefits arisewhen the impacts to commercial operations are taken into consideration.Reduced downtime and improved corrosion resistance translates to considerable life cycle cost savings ifalternatematerialsandcathodicprotectiontechniquesareutilizedtoconstructgates.Itappearsthatconcretegates offer the most promise in longterm cost savings. Significantly increased cycle time betweenmaintenance events coupledwith reduced downtime for eachmaintenance activity translates into highlyimprovedreliability,maintainability,andnavigationalbenefits.


CONVEYATCHAFALAYARIVERWATERTONORTHERNTERREBONNEMARSHES

A1 AddressflowconstrictionsintheGIWWatHouma

TherearetwoapparentflowconstrictionsintheGIWWatHouma:theHoumaTunnelandtheTwinSpan(see locationmapbelow). These itemswillpreventdesiredproposedAtchafalayaRiverdiversion flow fromgoingtotheeasternTerrebonneBasin.Thecurrentplanningrationaleviewsthisflowlimitationasaplanningconstraintgiventhebeliefthatthetunnelcannotberemoved(thisalsomakesanypossibleflowimprovementtotheTwinSpannoneffective).Ithasbeenrecentlydiscovered,however,thatLADOTDplanstobuildahighrisebridgeandtakethetunneloutofservice.SeebelowexcerptfromtheTriParishnewsserviceinHouma:

The new high-rise bridge over the Intracoastal Waterway that will be built to replace the Houma tunnel should be located where a railroad bridge now crosses the waterway close to Bayou Black, audience members said at a meeting last week in Houma.

The state Department of Transportation and Development formally kicked off the project with the meeting, intended for Terrebonne residents to suggest a variety of sites to build the bridge and to air their views on the project.

But the railroad bridge location near the south end of Dunn Street was the only site that was brought up by audience members.

R. Gary McClure, an engineer with the Baton Rouge firm Shread-Kuyrkendall & Associates who is studying the project, acknowledged that the railroad bridge site was being considered, as did a DOTD official at the meeting. The environmental impact of the new bridge would be minimal, according to McClure.

The tunnel, completed in 1961, is currently having 10 pumps replaced at a cost of $1.9 million and needs around $2 million worth of new lighting. McClure and the DOTD official said the tunnel experiences frequent traffic congestion.

State Sen. Reggie Dupre of Houma said the idea of replacing the tunnel has been around since the late 1990s. He said the three tunnels existing in the state - in Houma, Harvey and Belle Chasse - "are maintenance nightmares."

Once thereplacementbridge isconstructed, the tunnelcanberemoved. Itmaybenecessary,however, toacceleratethisbridgeprojecttoaccommodatetheLCAschedule.

Ifthetunnelcan indeedberemoved, itwouldthenappeartobepracticalto improvegravityflowacrosstheTwinSpanandeliminate theentireGIWW flowconstriction throughHouma. Thismaybeaccomplishedbyinstallingachannelsection through thenextbridgebenton theeastside (seebelowmap). Anallearthenchannel with rock and/or steel sheetpile protection of the bridge foundation or an earthen channel incombinationwithmultipleconcreteculvertsunder thebridgestructurepropercancreateanadequate flowsection.Thiswould,however,requirethepurchaseofanestimated15to20developedresidentialpropertiestothenorthandapartialvacant(industrial?)tracttothesouth.Whilepoliticallyundesirable,suchrealestatepurchaseispossibleanddoesnotappeartobecostprohibitive.


Ifonly limitedproperty canbeobtained, an alternativewouldbe topump through the samebridgebent,utilizingapump station to the southand several largediameter forcemainsdischarging to thenorth. ThiswouldbebothamoreexpensiveinitialcostoptionaswellasrequiresignificantfutureO&Mcost.

A rough cost estimate for removing the tunnel, purchasing property, and installing a gravity conveyancethroughthebridgeisintherangeof$7to$12million;removingthetunnelwithapumpingoptionthroughthebridgewouldbeontheorderof$20to$35million.Estimatedcostofitemsasfollows(design,managementandcontingenciesincluded):

GravityConveyance

Removaloftunnel $1$2millionRealestatetotalacquisitioncosts $2$4millionChannelcutwithculvertsunderbridge $4$6millionTotal: $7$12million

PumpedConveyance

Removaloftunnel $1$2millionRealestatetotalacquisitioncosts $1$3millionPumpstation(1,500CFS)andforcemains $18$30millionTotal: $20$35million

TWIN SPANBRIDGE

TUNNEL

EXISTING CHANNELCONSTRICTIONS OF

THE GIWW @ HOUMA


ESTIMATED REQUIREDPROPERTY PURCHASE

PROPOSED CHANNELWIDENING/CULVERT

PROPOSED CHANNELWIDENING OR CULVERT

UNDER TWIN SPAN

A2 OperatetheOldRiverControlStructuretooptimizeflowsplitoutsideofthe70/30mandateinnonfloodconditions

TheOldRiverconnectstheRed,Atchafalaya,andMississippiRivers. Inthe1890s,theAtchafalayaRiverwasexpandingandwouldhaveallowedtheMississippiRiverashorteroutlettotheGulfofMexico.Bythe1950s,itwas apparent thatAtchafalaya River could capture the entireMississippi River flow. In 1954, CongressauthorizedtheUSACEtoconstructtheOldRiverControlProjecttopreventtheMississippiRiverfromchangingcourse.ThislegislationobligatedtheflowbetweentheMississippiRiverandtheAtchafalayaRivertoremainatitsthencurrentrate,a70/30split.

ItappearspossiblethattheOldRiverControlStructurehasthecapabilitytoalterthisflowsplitduringlowflowconditions.Duringperiodsof low river flow, this30%allocationmaybe less thanneeded in theAtchafalyaRivertosupplythedesiredquantityoffreshwaterflows intotheGIWW. TheabilitytoalterthisflowrationmaybeimperativetoachievingtheprojectgoalofprovidingfreshwatertotheentireTerrebonneBasinwhenitwouldbeneeded.

Suchachangewouldrequireachange in federal law. The70/30splitwouldberetained,unaltered,duringnonlowflowtoavoidadverseaffects. Overtime,frequentandprolongeddeviationfromthe70/30splitatlowflowcouldpossiblychangetheriverbottomconfigurationenoughtoaffectfloodconditionperformance.Further evaluation would therefore be required before this change in operation would be implemented.Allowingflexibilitytoroutemorethan30%intotheAtchafalyaRiverwouldbecomeanadaptivemanagementstrategytomeetprojectsalinityreductionpurposes.

A3 UseCityofHoumawastewatereffluenttoreplenishcypressforests

Aprocessrecentlyutilizedandplanned inseveral localities istheuseofsecondarytreatedwastewaterplanteffluent to feednewlyplantedcypressstands. Suchasystemaccelerates treegrowthand treatssecondaryeffluentstotertiarystandards(aswellasreduceseffluentdischargetoreceivingwaterways). Thissystem is


currently being considered for inclusion in the LCA program in the Missouri River Gulf Outlet (MRGO)EcosystemRestorationProject(St.BernardParish).

Passingeffluentthroughnaturalormanmadevegetationhasbeenshowntosignificantlyimprovethequalityoftheeffluent.Thisalternativemeasurewouldallowtheeffluenttoflowoverandthroughthevegetationinthemarshland, creatinga filteringeffect thatwouldenhancewaterquality andaddnutrients to thebioticsystem.

The scienceaddressingContaminantsofEmergingConcern is still in its infancy. Should such contaminants(e.g.,pharmaceuticals,byproductsofplasticsandheavymetals)bepresent inthetreatedeffluent,theymaybe retained in the effluent;however, since this isnotpartof thedrinkingwater supply, the issuemaybeinsignificant. In fact,bydiverting theeffluent to themarsh rather than to the river, improvements to thedrinkingwatersupplyinthisrespectmaybeimproved.

It isnotknownwhat thecurrentwastewater treatment system status is for theCityofHouma (centralizedplant,numerousprivatelyrunpackageplants,etc.),butthismaybeapossibleconsiderationifatargetcypressplantingarea(orexistingstand)isrelativelyclosetoawastewatertreatmentsite(s).Thiscanbeawinwinalternativethatresultsinlowerwastewatertreatmentcostsandhabitatcreation/enhancement.

A4 PumpflowfromDavisPondDiversionfromCompanyCanal

A possible means of delivering freshwater produced by the Davis Pond Diversion westward into BayouLafourche (and indirectly into the Terrebonne Basin target area) may be by inducing westward flow inCompanyCanalviapumpingat theold lock location. Thisconceptwasdeveloped inapreviousVEStudyBayouLafourcheSiphonRestorationProject, July2001;ProposalC1 (seeAppendixC). Costandhydraulicconsiderationsmaylimitthisflowtolessthan1,000CFSbutthismaybeabeneficialsupplementtoproposedfreshwaterflowthatmayoriginatefromthewest(AtchafalayaRiverDiversion).

A5 UseBayouLafourchetoconveyfreshwatertothenorthernTerrebonnemarshes

In lieuoforcomplementarytoconveyingAtchafalayaRiverwatertothenorthernTerrebonnemars

value engineering report - lca v terrebonne final/appendices...value engineering study report...

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