WendyLathrop,PLS,CFMNFIPMappingIssues-January2018

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NFIPMappingIssuesWendyLathrop,PLS,CFMCadastralConsulting,LLC

NFIPBasicObjectives:Reducetheexposuretoflooddamagesthroughtheuseofminimumstandardsfortheplacementanddesignofstructureslocatedinfloodhazardareas.NFIPPurposes(42USC§4001)

• Identifyandmapfloodhazardareas• Provideaframeworkforfloodplainmanagementregulations• MakefloodinsuranceavailableincommunitiesparticipatingintheNFIP

Whymappingmatters

• Inaccuratemap=improperinsuranceandregulation• Nomap=insuranceand/orregulatoryrepercussions

NFIPRegulationsTitle44CFR-Part59-GeneralProvisions

• Definitions• Programdescription• Eligibilityrequirements

Terminology

• Flood• Floodfrequency• Floodplain• Floodfringe• Floodway• Basefloodelevation• Floodplainmanagement

FloodingtypesThreemaincategories:

• Riverineflooding• Coastalflooding• Shallowflooding

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NFIPZones:44CFR64.3• ZoneA• ZonesA1-A30,AE• ZonesAO,AH• ZonesA99,AR• ZonesB,ShadedX• ZonesC,UnshadedX

• ZoneV• ZonesV1-V30,VE• ZoneVO• ZoneD• ZoneE• ZoneM

RiverineWatershedandFloodplain

Floodway/FloodFringe

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CoastalHazards

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Other“Unique”FloodHazards• AlluvialFans• Migratingstreams• MudFlows• Ice/debrisJams• DamFailures• Tsunamis

LegacysedimentsMapevolution

• FloodHazardBoundaryMaps(FHBM)• FloodInsuranceRateMaps• FloodBoundary/FloodwayMaps(FBFW)• Digitalformat• DigitalFloodInsuranceRateMaps(DFIRM)

Thebirthofamap

• Mappingneedsassessment• Determinationofresources• Scoping• DataCollection• DataAnalysisandcompilation

HowtomakeaFIRM/DFIRM44CFR65:IdentificationandMappingofSpecialHazardAreas“ThepurposeofthispartistooutlinethestepsacommunityneedstotakeinordertoassisttheAgency'seffortinprovidingup-to-dateidentificationandpublication,intheformofthemapsdescribedinpart64…”

GuidelinesandStandards:MasterIndexGuidelinesandSpecificationsforFloodHazardMappingPartners

• Acompilationofresources• 3volumes,14appendices• Someitemsmarked“superseded”butnotfullyreplaced;useasbackground• http://www.fema.gov/media-library/resources-documents/collections/361

ThemultiplepurposesofFIRMs

• Insurancerating• LendercompliancewithNFIP• Eligibilityfordisasterassistance• Landuseregulation

• Planning• Emergencymanagement• Landdevelopment• Appraisal

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Approachestomappingfloodplains• Approximatemethods• Limitedstudymethods• Detailedmethods• Limitedmapmaintenanceprojects• Restudies

WhataFIRM/DFIRMtellsus

• Floodrisklevels• Flood“protection”• Floodcontainment• Levelofdetail• Limitofdetail• RefertoFIS

FloodInsuranceStudyReport-Thedetails“MapModisDead,LongLiveRiskMAP”“…todeliverqualitydatathatincreasespublicawarenessandleadstoactionthatreducesrisktolifeandproperty.”Digitalmapping“Digital”mappingmayormaynotbeofbetterqualitythannon-digitalversions

• Scannedpapermaps• Fielddataconvertedtodigitalfilesforanalysisanddigitalmapcreation• Fielddatacollectedasdigitalfilesforanalysisanddigitalmapcreation• Digitalphotography• 3-DLaserscanning

ProcedureMemorandum38

• Dataconsistencystandard,not“accuracy”standard

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Lookatthemetadata“BaseMapSource:1:100,000USGSDigitalLineGraphs.Mapusersshouldbeawarethatthisbasemapsourcecausesroadalignmentdistortionsatandnearroadintersections.Thesealignmentproblemshavebeencorrectedinthevicinityofidentifiedfloodplains.”Theadoptionofamap

• Preliminarymapping• Publichearings• FEMAreviewofappeals• LetterofFinalDetermination

NFIPRegulations-Title44CFR,Part67AppealsfromProposedFloodElevationDeterminations

• Rightofappeal• Typesofappeals• Appealprocedures

Keepingmapscurrent

• Originallackofmappingdetail• Topographicchanges• Imperviouscoverchanges• Structuralchanges• Hydrologicandhydraulicchanges• Jurisdictionalchanges

Remember-themapisasnapshotofconditionsatagiventimeResponsibilityformapping44CFR65.3–Requirementtosubmitnewtechnicaldata“…notlaterthansixmonthsafterthedatesuchinformationbecomesavailable,acommunityshallnotify[FEMA]ofthechangesbysubmittingtechnicalorscientificdata…”

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FutureconditionsAdvisorymappingThevolatilityoferosion(and/orsubsidenceand/orsealevelrise)LOMCs

• OfficiallyamendorrevisetheFloodInsuranceRateMap(FIRM)WhyLOMCs?

• Lessexpensivethanrepublishingthemaps• Fasterthanrepublishingthemaps• Scalelimitations• Timeandnoticeconsiderations

Elevationmatters!

• Whereis“zero”?• Heightoffloor• Heightofwater• Inherentuncertainties• Benefits/costs

KeyTermsforLOMCs

• LowestAdjacentGrade(LAG)• HighestAdjacentGrade(HAG)inZoneAO• BaseFloodElevation(BFE)• Fill• LowestFloor• Basement

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Mapupdates–amendments• LetterofMapAmendment–sitespecific• Inadvertentinclusionstofloodplain• Structuresorlegallydefinedparcels• Donotinvolvehydrologicorhydraulicanalyses(unlessZoneA)• UseMT-1(orMT-EZ)• e-LOMAconsiderations

NFIPRegulations-Title44CFR,Part70-ProcedureforMapCorrection“MappingDeficienciesUnrelatedtoCommunity-WideElevationDeterminations”

• Righttosubmittechnicalinformation• LettersofMapAmendment• Reviewofproposedprojects

TheFIRMtakesprecedenceoverelevation.IfthegradeisaboveBFE,requestaLOMA.44CFR70.3–LOMADataintheapplicationmayinclude:

• Topographicmapping• NotopographyneededifaplotontheFIRMshows“outasshown”• LAG(includingattacheddecks,garages)• Mapshowinglocationofstructure• Curvilinearlinerepresentingareasubjecttoinundationbythebaseflood

HomeownercansubmitapplicationCrossSectionalViewofaLOMARequest

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TypicalSourcesofBFEs• FEMAFloodInsuranceStudyReportprofile• FEMAFloodInsuranceRateMap• Other1%annual-chanceFloodStudy• FEMAQuick-2software• Streamgaugedata• Extrapolationofdetailedstudyupstream• Newdetailedstudy

NoBFE–nowwhat?FEMAPublication265(1995):

• “ManagingFloodplainDevelopmentinApproximateZoneAAreas:AGuideforObtainingandDevelopingBase(100-Year)FloodElevations"

ApproximateBFEmethods

• Historicalhighwatermarks+safetyfactor• Watercontrolstructure+freeboard• Matchtopography• “Contour”method(a.k.a.“pointonboundary”)

LOMAinZoneA

• MAYbeabletocompleteLOMAwithoutengineer:o Includeallavailableinformationregardingstructurelocation,topography,

FIRMs.• Iftooclosetocall,considerotherapproaches:

o ExtrapolationofBFEsfromnearbylocations• Ifnoneofthesimplifiedmethodsareappropriate,surveyedcrosssectionsand

engineeringmethodsarerequired.ApplyingforaLOMAOutcome(whatisremovedfromSFHA)

FloodZone BFE LAG LFE LowestLotElevation

Building200 X(unshaded)

13.8feet 21.8feet 23.3feet -

Outcome(whatisnotremovedfromSFHA)

FloodZone BFE LAG LFE LowestLotElevation

Structure AE 1494.9 1493.2 1495.8 -

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Outcome(whatisoutsideSFHA)

FloodZone BFE LAG LFE LowestLotElevation

Residentialstructure

C - - - -

e-LOMA

• On-lineapplication• Restrictions:nofill;BFEavailable• Auditing• ImplicationsforlocalcommunitiesandotherswhoutilizeLOMAs• DiffersfromonlineLOMCapplication

Mapupdates–revisions

• Engineeredchangeso LetterofMapRevisiono LetterofMapRevisionbasedonFillo Physicalmaprevisions

• Morecomplexthanamendments• Notusuallylotorstructurespecific• Typicallyinvolvehydrologicand/orhydraulicanalyses• RequiresubmittalofMT-2forms

NFIPRegulations-Title44CFR,Part65IdentificationandMappingofSpecialFloodHazardAreas

• Requirementtosubmittechnicaldata(65.3)• Righttosubmitnewtechnicaldata• Maprevisions• Floodways• Levees

44CFR65.5-LOMR-FRequestormustsubmit:

• Copiesofrecordeddeedandplats• Topographicmapindicatingpresentgroundelevationsandfill• LocationofstructureandLAGelevation• BFEdatafromauthoritativesource• Communityacknowledgementform(MT-1)

DefinitionofLowestFloor“...thelowestfloorofthelowestenclosedarea,includingbasement.Anunfinishedorfloodresistantenclosure,usablesolelyforparkingofvehicles,buildingaccessorstorageinanareaotherthanabasementareaisnotconsideredabuilding’slowestfloor;providedthat

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suchenclosureisnotbuiltsoastorenderthestructureinviolationoftheapplicablenon-elevationdesignrequirementsofSec.60.3.”DefinitionofBasementThatportionofabuildinghavingitsfloorsubgrade(belowgroundlevel)onallsides.Cross-SectionalViewofaLOMR-FRequest

LOMR-F–Whydidthisapplicationfail?Outcome(whatisnotremovedfromSFHA)

FloodZone BFE LAG LFE LowestLotElevation

Structure AE 63.3feet 62.3feet 60.5feet -Newmap–nowwhat?

Incorporated? ORRevalidatedandreauthorized? ORSuperseded?

ConditionalLetters

• Reviewofproposedprojects• CLOMA:44CFR70.9• CLOMR:44CFR65.8• Noeffectoninsurance• FinalLOMCrequiresas-builtcertification

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NFIPRegulations-Title44CFR,Part72ProceduresandFeesforProcessingMapChanges

• DefinesCLOMA,CLOMR,CLOMR-F,LOMR,LOMR-F,PMR• Feeschedule• Submittalandpaymentprocedures• Feeexemptions• Resubmittals

Ms.Alpha

• Herhouseisawood-framestructurewithFFEof712.3NGVD,abasementelevationof702.8,LAGis711.2.

• Fillwasplacedforconstructionin1999.Thefloodinsurancemap(thenaFHBM)wasfirstprinted1997,butWalnutCreek(floodingsource)wasn’tshownasafloodhazarduntil2003.

• NewstudywillincludearestudyofWalnutCreek.CurrentBFEis710.5, whilerestudyshows711.2

• WhichLOMC?Shoulditbeapproved?Whataboutafterthenewstudyispublished?Mr.Beta

• HishouseisabrickstructurewithaFFEof858.2NGVD,acrawlspaceelevationof849.00,andLAGis853.4.Engineeredfillwasplacedduringconstructionofthehomein2014.

• TheFIRMforthiscommunityisdated1995,anditisthefirstNFIPmapshowingSFHAsinthisarea.Mr.Betapreviouslysubmittedandreceivedaconditionalletterin2013.

• ShouldhishouseberemovedfromSFHA?Whattypeoflettershouldheapplyfor?