the incorporation of rainfall into hazard estimates for

CRC2ndAnnualMeetingFeb.1-3,2017TheUniversityofNorthCarolinaatChapelHill

TheIncorporationofRainfallintoHazardEstimatesforImprovedCoastalResiliency

DonaldT.Resio– UniversityofNorthFlorida([email protected])BruceA.Ebersole – JacksonStateUniversity ([email protected])

JohnAtkinson– Arcadis,Inc. ([email protected])


BruceEbersole (JSUMPIandleadstakeholderGroupcoordinator)hasformedanend-usercommitteetoprovidereview,feedbackandrecommendationsontheworkinprogress.FEMAHQFEMARegionIFEMARegionIIFEMARegionIIIFEMARegionIVFEMARegionVIUSCoastGuardUSACENOAA

EndUserEngagement


EndUserEngagement

• DirectcallswithStakeholderGroup(SG)members

• Semi-annualprogressreportssenttoSG(firstsentinJuly).

• BruceEbersole isfacilitatingcommunicationswiththeSC

• Interactionratewillincreaseinsecond12-monthsofproject,possiblyincludingwebinarsandon-sitemeetings


KnowledgeGapAddressedbyProject

• FEMAfloodmodelingandstatisticalmethodscurrentlytreatstreamandrainfall-inducedfloodingseparatelyfromcoastalflooding,whichleadstoaswathoflandbetweenthetwoapproachesthatisunder-estimated

• Statisticalmethodsandmodelingmethodshavetobeupdatedtoexplorethefollowinggoals:• Acoupledmodelingsystemthatisdefensibleandaccurateforallcriticalprocesses

affectingfloodingincoastalareasandisadaptabletoallcoastalareaswithintheU.S.• Astatisticalmethodologythatiscapableofincorporatingadditionalsourcesof

variationininundationlevels,whilepreservinganoverallefficiencythatallowsthecoupledmodelingsystemtobeappliedeffectivelytoallcoastalareaswithintheU.S.


• Re-examinefundamentalassumptionswithinstatisticalmethodologies,particularwithrespecttoeffectsofnaturalstructureonprobabilities(JPsubmittedtoNaturalHazards)

• QuantifyrelationshipsbetweenTropicalCyclones(TCs)andrainfallpatternsaffectingfloodingincoastalareas

• Developstatisticalframeworkforestimatingprobabilitiesofcoastalinundationthatmaintainsaccuracystandardsandoverallefficiencyintermsofnumbersofsimulationsrequired

• Investigateoptionsformodelcouplingthatprovidethefollowing:• abilityofrivermodelstoaccountforsurge• abilityofsurgemodelstoaccountforriverflow&stage• accuratecoupledmodelsystemthatreproducesimportantphysics• systemthatisstable&computationallyefficient

ResearchApproach


• Completedanalysisofrainfallpatternsandstatisticalframeworkforcombiningrainfall,tides,river/streamdischargeandantecedentconditionsintoastatisticallyrobust,defensiblemethodology,efficientandadaptabletomultiplelocations(Reportcompleted1/31/2017)

ResearchWorkandAccomplishments(RainPatterns&Statistics)

• Findingstodate:• RainfalloffshoreisinfluencedprimarilybySeaSurfaceTemperature(SST)andStormSize• TimingofrainfallwiththepointofclosestproximityofstormcentertoNorfolksuggeststhatthe

onshorerainfallslightlylagsthestormpassage,butismainlyconcentratedina24-hourintervalcenteredonthepointofclosestapproachinhurricanesintheNorfolk/HamptonRoadsarea

• Stormtrackistheprimarydiscriminatorofboththedurationandintensityofrainfallinstorms• ResponseFunction(RF)methodismuchmoreadaptablethanBayesianQuadrature(BQ)for

incorporationofspatiallyinhomogeneousprocessesintostatisticalframework


ResearchWorkandAccomplishments1

Rainfallfromall17“major”stormsintheNorfolkarea

14

2

3

1– Surgeandhighrainfall2– Littlesurgeandmoderaterainfall3– Moderatesurgeandhighrainfall4– Littlesurgeandlittlerainfall

EOFsforMajorStorms EOFsforMinorStorms

TrackCategorization


ResearchWorkandAccomplishments2

Hydrologic

Coastal Coastal

Hydrologic

Combined

AnnualExceedanceProbabilityforcoastalsurgesandcoupledcoastalandhydrologic/rainfallflooding

EXAMPLESOFEXPECTEDSTATISTICALPRODUCTSFROMTHEOVERALLPROJECT


ResearchWorkandAccomplishments(CoupledModeling)

• Investigatedimpactofprecipitation&riverstageonsurge(whatarewemissinginpresentmethodology?)• UsesNechesRiver(Texas)astestcase• Procedure

• ObtaintwoexistingmodelsthatincludetheNeches• 2DsurgemodelfrompreviousTX-FEMAstudy• 1DriverinemodelfromUSACE• Comparesimulationsforseveralevents• Systematicallyadjustdomainoverlapandboundarylocation• Optimizethe“best”couplingprocess• Identifythephysicalconditionsthatimpactthecouplingstrategy



HEC-RAS•Wellknownandrespectedmodeltocomputestage-flowrelationshipsforriversandstreams•Canbeusedinunsteadymodewithtimevaryingboundaryconditions•Sourcecodeisnotpubliclyavailable•Veryefficientperstorm,butnoteasilyautomated

•Existing,calibrated/validatedHEC-RASmodelofNechesRiveravailablefromUSACE•USACEmodelmodifiedandcoupledwithTX-FEMAADCIRCmodel


• One-waycouplingappearsfeasibleforcoupledsimulations(usingsubdomain+BC)• AutomationdevelopedforHEC-RASusingVBAandMatlab calls• RainfallcanbeaddedonADCIRCsub-domainbasiswithBC• TimingoffloodinginHEC-RASandADCIRCinphaseinmosttests• HEC-RAShasmoredampingthanADCIRC• HEC-RAScannotaccountforeffectsofLakeSabine(implicationsforHamptonRoads

andotherregions)• HEC-RASdoesnotaccountforwind• Other1Drivermodelsmayperformbetter(SOBEK,SWAT)• Forallsurgeconditions,totalstage(backwatercurve)inriverincreasewithflowrate• Forincreasingsurge,HEC-RASunderpredictstotalsurgeby1to2ft

ResearchWorkandAccomplishments(ModelCoupling– draftconclusions)



ModelComparisonforHurricaneIke


EducationalEfforts

• ParticipatedinSUMREXProgramwithRudyBartels– PhDstudentfromLSU

• PlansinplacetogiveresearchpresentationatLSUandcontinueworkwithRudyBartelsandProfessorBarryKeim forajournalpublication

• UNFPhDstudentAmandaTritingerparticipatedinlastyearsCESonbehalfofDHS

CRC1st AnnualMeetingMarch2-3,2016TheUniversityofNorthCarolinaatChapelHill

• DHSGoal1.3– ManageRiskstoCoastalInfrastructure,KeyLeaders,andEvents: Pasteventshavedemonstratedthreatposedtoinlandareasisoftenunderestimated,withdamagesduetoinlandfloodingcomparabletoareasatthecoast.Thisprojectwillhelpremediatethisdeficiency,therebyenhancingourdecision-makingcapabilitiesrelatedtoresilience.

• DHSGoal5.1– MitigateCoastalHazardsandRisks:Multidisciplinaryteamswillbeutilizedtodevelopimprovedhazardmapsincoastalareasthatwilldispersecostsmoreequitably.

• DHSGoal5.3– EnsureEffectiveEmergencyResponse :Thisprojectwillprovideimprovedquantitativetime-spacepatternsofeventhazards,whichwillbeveryvaluabletoemergencyresponders.

• DHSGoal5.4– RapidlyRecoverfromCatastrophicEvents:Thisprojectwillprovideaccurateinformationontheinteractionofhazardswithcriticalinfrastructureandthepatternsoftheseindividualhazardsduringindividualevents,asneededforeffectivepost-disasterplanningandforminimizingfutureexposure.

AnticipatedProjectImpact(1)


• Developandtestastatisticalandmodelingframeworkovertheexpectedrangeofforcing.

• Delineatemagnitudesandareasofsignificantdifferencesandinvestigateimpactsoninundationprobabilities

• DevelopobjectivemethodologyforRFapproachtostormselectionthatincludesrainfall,hydrologicinputs,andantecedentconditions.

• Evaluateperformanceofthenewlyreleased2DversionofHEC-RAS• Compare2DHEC-RASperformancewithSOBEKand/orSWATforADCIRCcoupling• Deploycoupledsystemondifferentriversystemtoseeifconclusionsaregeneral

(possiblylowerJamesRiverarea)• Includeprecipitationinsurgemodel• Definea“flashiness”parameterforriverbasinstoidentifywherecouplingismore

importantduringprecipitationevents

ExpectedFutureResearchWorkandAccomplishments


• Developtestconcepts(withstakeholderinput)forNorfolk-HamptonRoadscoupledsurge-rain-hydrologicmodelingsystem

• UsingexistingdatafrompreviousFEMAfloodmapstudiesinthisarea,developasetofsub-domainmodelsfortesting.

• Investigatethestabilityandaccuracyof1-waycouplingto2-waycoupling• Estimatetheareasandsignificanceofimpactsofcoupledmodelingcomparedto

surge-onlymodeling• Evaluatethemodelingsystemandstatisticalframeworkfortransitiontofull-

scaleapplications• Providerecommendationsonanyneededalterationstothesystemneeded

beforetransition,ifany

ProposedFollow-onWork

the incorporation of rainfall into hazard estimates for

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