USF Libraries
USF Digital Collections

What we have learned since the Big Thompson flood

MISSING IMAGE

Material Information

Title:
What we have learned since the Big Thompson flood proceedings of the tenth anniversary conference, July 17-19, 1986, Boulder, Colorado
Series Title:
Special publication / Natural Hazards Research and Applications Information Center ;
Physical Description:
271 p. : ill. ; 23 cm.
Language:
English
Creator:
Gruntfest, Eve
University of Colorado, Boulder -- Natural Hazards Research and Applications Information Center
Publisher:
Natural Hazards Research and Applications Information Center
Place of Publication:
Boulder, CO (Campus Box 482, Boulder 80309)
Publication Date:

Subjects

Subjects / Keywords:
Flood control -- Congresses -- Colorado -- Big Thompson River Watershed   ( lcsh )
Floods -- Congresses -- Colorado -- Big Thompson River Watershed   ( lcsh )
Flood forecasting -- Congresses   ( lcsh )
Natural disaster warning systems -- Congresses   ( lcsh )
Genre:
bibliography   ( marcgt )
conference publication   ( marcgt )
non-fiction   ( marcgt )

Notes

Bibliography:
Includes bibliographical references (p. 264-271).
Additional Physical Form:
Also issued online as part of a joint project with the Louis de la Parte Florida Mental Health Institute (FMHI) Research Library's disaster mental health initiative.
Statement of Responsibility:
Eve C. Gruntfest, editor.

Record Information

Source Institution:
University of South Florida Library
Holding Location:
University of South Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 001985070
oclc - 16266475
lccn - 87623634
usfldc doi - F57-00060
usfldc handle - f57.60
Classification:
lcc - TC425.B49 W47 1987
ddc - 363.3/493/09788
System ID:
SFS0001141:00001


This item is only available as the following downloads:


Full Text
xml version 1.0 encoding UTF-8 standalone no
record xmlns http:www.loc.govMARC21slim xmlns:xsi http:www.w3.org2001XMLSchema-instance xsi:schemaLocation http:www.loc.govstandardsmarcxmlschemaMARC21slim.xsd
leader cam 2200349 a 4500
controlfield tag 001 001985070
005 20090317165342.0
008 880226s1987 coua b 100 0 eng
datafield ind1 ind2 010
subfield code a 87623634
8 024
F57-00060
035
(OCoLC)16266475
040
DLC
c DLC
d DDB
OCL
BTCTA
043
n-us-co
0 050
TC425.B49
b W47 1987
082
363.3/493/09788
2 20
086
HED2/320.12/16
codocs
245
What we have learned since the Big Thompson flood :
proceedings of the tenth anniversary conference, July 17-19, 1986, Boulder, Colorado /
Eve C. Gruntfest, editor.
260
Boulder, CO (Campus Box 482, Boulder 80309) :
Natural Hazards Research and Applications Information Center,
1987.
300
271 p. :
ill. ;
23 cm.
1 490
Special publication / Natural Hazards Research and Applications Information Center ;
v #16
504
Includes bibliographical references (p. 264-271).
530
Also issued online as part of a joint project with the Louis de la Parte Florida Mental Health Institute (FMHI) Research Library's disaster mental health initiative.
650
Flood control
z Colorado
Big Thompson River Watershed
Congresses.
Floods
Colorado
Big Thompson River Watershed
Congresses.
Flood forecasting
Congresses.
Natural disaster warning systems
Congresses.
700
Gruntfest, Eve.
710
University of Colorado, Boulder.
Natural Hazards Research and Applications Information Center.
773
t Natural Hazards Center Collection
830
Special publication (University of Colorado, Boulder. Natural Hazards Research and Applications Information Center) ;
16.
TKR
ARL-FMHI
049
FHIM
994
C0
FHI
029
AU@
000007474365
938
Baker and Taylor
BTCP
n 87623634
4 856
u http://digital.lib.usf.edu/?f57.60



PAGE 1

WhatWeHaveLearned SincetheBig Thompson FloodProceedingsoftheTenth AnniversaryConferenceJulyI7-19. 1986 Boulder,Colorado

PAGE 2

WhatWeHaveLearned SincetheBig Thompson FloodEveC.GruntfestEditorProceedingsoftheTenthAnniversaryConferenceJuly17-19. 1986 Boulder.ColoradoNatural Hazards Research and Applications InformationCenterSpecial Publication#161987

PAGE 3

Theopinionsandrecommendations contained hereinarethoseofthe authorsandconferenceparticipants,anddonot necessarilyreflectthose of the funding or sponsoring agencies or organizations.Coverphoto:Scenein theBigThompsonCahyon,Colorado,onAugust1,1976.Availablefrom:TheNatural Hazards ResearchandApplications Information CenterInstituteofBehavioral Science University of ColoradoCampusBox482Boulder,CO80309

PAGE 4

INTRODUCTIUNTheSymposiumheld in BoulderonJuly17-19, 1986,offeredarareopportunitytolook backandassessthestrengthSandweaknesses ofpostdisasterresearchandpolicyinitiatives.Themeeting drewtogetherparticipantsfroma wide range ofdisciplinestoanalyzethepremisethatdisastersareopportunitiesforchange,andtosettheflashfloodresearchandpolicyagendafortheremainder ofthecentury.PartOneprovidesanoverview oftheBigThompsonflood inlightofrecentexperiences.Gruntfest's"CommonGround"describesthefloodandappraisestheprogress inflashflood hazardmitigationintheBigThompsonCanyon,thestateofColorado,andtheUnitedStatesas a whole.Inhispaper,Wright,thegovernor'srepresentativetotherecoveryeffort,reflectsonthestate'srole.Kistnerpresentsanoverview ofthe1982EstesPark dam-breakflood,analyzinghowthe1982recovery processwasinfluencedbylessonslearnedafterthe1976BigThompsonexperience.Charney,forensicanthropologistin charge ofbodyidentificationaftertheBigThompsonflood,discussestheoperationof a temporarymorguefollowing adisaster,afrequentlyignoredaspectof emergencypreparedness.PartTwoiscomprised oftenpapersthataddressmitigationissues,as theyariseatvariouslevelsof government.Atthefederallevel,SteinbergpresentstheCorps of Engineers' flooddamagereductionprogram,andOlsonandGorediscussdirectionintheNational Flood Insurance Programsince1976. Truby,Stanton,andWright examinestatemitigationefforts:Truby focusesondamfailurehazards;StantonconcentratesontheColorado Flood HazardMitigationPlan;andWright provides alegislator'sperspectiveinappraisalofmitigationeffortsoverthelastdecade. Regionalandlocal impactsareconsidered in papersbyDeGrootandTuckerandHavlick.DeGrootandTucker'spaperidentifiesthenationallyrecognizedeffortsoftheUrbanDrainageandFlood ControlDistrictintheDenvermetropolitanarea.AsamemberoftheBoulderCityCouncil,Havlick looksattheimpactstheBigThompsonflood hashadin Boulder,35milesawayfromtheBigThompsonCanyon.Themitigationsectionisrounded outbyPlatt'spaperonthepost-disastermitigationteamsbegunbyFEMAin 1979,andbyDye'sdiscussionoftheprivatesector'sroleinsellingfloodinsurance.

PAGE 5

PartThree coversforecastinginnovations.ThepaperbyBelvilleandWagonerprovidesanoverview of changes in National WeatherServicepoliciesandprogramssince1976. Johnson'spaper,theTuckerandReitercontribution,andScofield'spaper dealprimarilywithinnovationsinforecastingmodels of hydrologic systemsandprecipitation.Thesectionconcludes with a paperbyVanBlargenidentifyingthetechnologicaladvancements inflashfloodforecastingwithintheNational Weather Service inthepastdecade.PartFourconcentratesonwarningandresponse. Graham's paperdetailsthewarning experience precedingthe1982Estes Parkdambreak.Boulder'ssophisticatedautomatedflashflood warning systemisdescribedbyVanWie.Sorensen examinesthe1985Cheyenne flood warning systemandcomparesthesituationtotheBigThompson.Minnesota'sinnovativenetworkfordisasterstressinterventionisdescribedbyHuber.HandmerandPenning-Rowsell'spaperdiscussesAustralianexperiences with flood warnings.HostetterwrapsupthesectionwithhispaperonMennonitestudiesofsocialimpactsofdisasters.PartFivecontainspapersongeomorphologyandhydrology.Jarrettdocuments hydrologic researchrelevanttothe1976flood,andHoyt's paper comparestheBigThompsonimpacts withthoseofthe1982Estes Park dam-break floodPartSixincludesasummaryoftherecommendationsmadebyparticipantsintheSymposium.TheSymposiumparticipantlistisincluded as AppendixI.AppendixIIhas background papersforadditionalinformationontheactionspeople took duringtheflood,andonthelandacquisitionprogram implemented followingtheflood.Abstractsof papers not included intheProceedings butpresentedattheSymposiumarein AppendixIII.AnextensivebibliographyofarticlesandbookswrittenontheBigThompsonfloodservesas AppendixIV.

PAGE 6

ACKNOWLEDGEMENTSPresentationsmadeduringtheSymposiumformthebasisfortheseProceedings.amgratefultoallwhotookthetimetomaketheircontributions.ThenamesofalltheSymposiumparticipantsareprovidedinAppendixI.J.Eleonora Sabadell oftheNational Science Foundation,andDennis Walts oftheNational OceanicandAtmosphericAdministrationEnvironmental ResearchLaboratoriesprovidedfinancialsupportfortheSymposium. William DonovanoftheUnitedStatesArmyCorps of Engineers fundedthepublicationoftheProceedingsvolumebytheNatural Hazards ResearchandApplicationsInformationCenter. William Anderson oftheNational Science Foundation,andJames Null,DeanoftheCollegeofLetters,ArtsandSciences,Universityof Colorado, ColoradoSprings,providedinitialencouragementandsupportfortheproject.Technical supportandearlyencouragement were providedbyanadvisory committeethatincludedCurtisBarrett,National OceanicandAtmosphericAdministration; William Gordon, Larimer CountyOfficeof Emergency Management; Brian Hyde, Colorado Water Conservation Board; JonKusler,J.A.KuslerandAssociates;DaleLillie,National WeatherService,KansasCity;ThomasMcKeeandDennisMileti,ColoradoStateuniversity;MauricePautz,National Weather Service DenverForecastingOffice;RutherfordPlatt,UniversityofMassachusetts; John Swanson, Federal EmergencyManagementAgency; Jack Truby, Colorado Department ofDisasterEmergencyServices;Susan Tubbesiny, Natural Hazards ResearchandApplicationsInformationCenter;andDennis Walts, National OceanicandAtmosphericAdministration,Environmental ResearchLaboratories.ThesuccessoftheSymposiumdependeduponmanyindividualsandsponsoringorganizations.JonKusler,RutherfordPlatt,andJohn Handmer, oftheAustralianNationalUniversity,wereata meeting in GreatBritainwheretheinspirationfortheSymposiumfirstcame.ThestaffoftheNatural Hazards ResearchandApplicationsInformationCenter,inparticularSusan TubbesingandSarahNathe, deservespecialmentionfortheiradvicefromthetimetheSymposiumideafirsthatched in 1984,tothepublicationoftheProceedings in 1987.StaffoftheDisasterAssistanceProgramatFEMA/RegionVIII in Denver

PAGE 7

wereespeciallyhelpfulinstartingtoimplementtheplans.Post-SymposiumcommentsfromHowardGaskill,NewHampshire Civil Defense; Lawrence Kollenbrander, Western CarolinaUniversity;H.JamesOwen,Flood Loss ReductionAssociates;BorySteinberg,U.S.ArmyCorps of Engineers;GilbertWhite,Universityof Colorado;andJamesWright, Tennessee ValleyAuthority,help pavethewayforapplicationoftherecommendations. Special thanksareduetoGilbertWhiteforhisexcellentclosingremarksandforhiscontinuinginspiration.Thesupport teamfortheSymposiumwassuperb.CaroleHuberapplied herkeenbrainandstrongorganizationalabilitiesbefore,during,andaftertheSymposiumandkeptusallonschedule.MaryMcCutchen,SkyeRidley,DonnaHuntington, Joni Stephens,andLucyBrookeoftheFederalEmergencyManagementAgency,andKateOrdassistedwiththeregistrationandfieldtripdetails.EveC.GruntfestConference OrganizerUniversityof ColoradoatColorado Springs

PAGE 8

TABLEOFCONTENTSIntroductionAcknowledgementsPARTONE:THEFLOODINCONTEXTCommonGroundEveC.GruntfestStateResponsetotheBigThompsonCanyonDisasterKennethR.WrightFlash Flood Preparedness of PublicEntitiesin Colorado BrianHyde.BuildingonaDisasterRobertL.Kistner.TheTemporaryMorgueOperationMichael CharneyPARTTWO:MITIGATIONMEASURESPolicyChangesAffectingtheCorpsof Engineers FloodDamagePreventionProgramBorySteinbergTheBigThompsonDisaster--ThenandNowJeromeM.OlsonTheNational Flood InsuranceProgram1976-1986 DouglasGoreTheDamFailureHazard:AwarenessandPreparedness in Colorado JackTrubyChangesInOurUnderstanding of Mitigation WilliamP.StantonChangesattheStateLevelSince1976RuthM.Wright.iiiv3 91719222735 41 505257

PAGE 9

Successful FloodManagementona Regional Basis WilliamG.DeGrootandL.ScottTucker.HowtheBigThompsonFlood has Affected Local Flood PreventionEffortsSpenserW.Havlick.Post-Flood HazardMitigation:A Legacy of Big ThompsonRutherfordH.PlattInnovations in thePrivateHandling of Flood Insurance WilliamM.Dye. PARTTHREE:FORECESTINGINNOVATIONSTheNWSFlash Flood Program:ThePresentandtheFutureJamesD.BelvilleandRichard AWagonerHydrologic Modeling Using Radar-Rainfall ImageryLynnE.Johnson..OrographicPrecipitationModelForecast oftheBigThompsonFloodDonnaF.TuckerandElmarR.Reiter.OperationalSatellite-DerivedPrecipitationEstimatesandForecasts RoderickA.ScofieldTechnological Developments in Flash FloodForecastingWithintheNational Weather ServiceEdwardJ.VanBlargan.PARTFOUR:WARNINGANDRESPONSEFlash FloodWarningEffectivenessWayneGraham.TheBoulder Flash Flood DetectionandWarningSystem DonaldG.VanWieWarningSystems inthe 1985 Cheyenne Flash Flood JohnH.Sorensen. MinnesotaNetworkforDisasterStressInterventionJosephHuber68758292101109 119127136149166174 184

PAGE 10

LessonsfromAustralianWarningExperienceJohnW.HandmerandEdmundC.Penning-RowsellTheSocial Impacts of DisastersandEmergenciesC.NelsonHostetterPARTFIVE:HYDROLOGYANDGEOMORPHOLOGYHydrologic Research Relatedtothe1976BigThompsonRiver Flood RobertD.JarrettAGeologist'sPerspective ofthe1982Estes Park Flood WilliamH.HoytPARTSIX:WHEREDOWEGOFROMHERE?PolicyandResearchRecommendationsEveC.GruntfestAPPENDICESI.ParticipantListII.SupplementalBackgroundInformation.III.Abstracts of Papers not Included intheProceedingsIV.Bibliography189 198203 213223 233241248260

PAGE 11

ThispageISblank

PAGE 12

PARTONETHEFLOODINCONTEXT

PAGE 13

ThispageISblank

PAGE 14

COMMONGROUNDEveC.GruntfestDepartment of GeographyandEnvironmentalStudiesUniversityof Colorado, Colorado Springs This paperisdividedintofourparts:anoverview oftheBigThompsonfloodforthosewhowere not"onthescene" in 1976,therationalefororganizingthisSymposium,initialthoughtsonwhat hasandhas not beenlearnedsincetheBigThompsonflood,andreflectionsonthechallengesforthefuture.TheFloodTheBigThompsonCanyonisoneofthemostscenicintheRockyMountainregion.U.S. Route34runs throughthecanyon,adjacenttotheriverinmanyspots.ItisthemainlinkbetweentheplainsandRockyMountain National Park. Beforetheflood,thefull-timecanyonpopulationwas600andtheparttimeresidentsnumbered approximately twicethat.There weremanytouristsattractedbythetroutfishing,streamsidemotels,andcampgrounds. Therearethreemajor communities inthe25-mile canyon(seeFigure1).WestfromLovelandtheyare:1)CedarCovejustabovetheNarrows;2)Drake,thelargestcommunity,locatedattheconfluenceoftheNorthForkandtheMainForkoftheBigThompson;and,3)GlenComfort.OnecommunityontheNorthForkoftheBigThompson,GlenHaven,wasalsoaffectedbytheflood.OnJuly31, 1976,theBigThompsonCanyonwasfilledwithtourists.ItwastheSaturday oftheweekendcommemoratingColorado'sCentennialandthelastholidayweekendbeforethestartofschool.Thatnightaflashflood ravagedthecanyon, causingtheworstnaturaldisaster,in terms ofliveslost,inColoradostatehistory.Heavyrainfellover a70square-mileareainthecentralportionoftheBigThompsonwatershed between 6:30and11:00pm.Themostintenserainfall,over12inches,fellover slopes inthewesternendofthecanyon (see Figure2)Theimpact oftheflood could have been worse.TheNorthForkpeak streamflow occurred approximately40minuteslaterthantheMainForkpeak.Ifthetwopeakshadcoincided,thepeak streamflowwouldhave been evengreater

PAGE 15

oz....Jw 6 ....Jo t< z-

PAGE 16

.......... .....Il",,,,.t"ry ,,! IJrtritrllJ,:" Arl'" ....-. j.... ......() ""I\V,"rtll",rr 1\ .... 1\ .1'I,r",;'w,1hyt:!'iC;!'i:; !! Sill IIll, .'Iil,.,. IIIFIGURE2TOTALPRECIPITATION(in inches) July31-Aug.2,1976(FromNOAA,1976,p.3,andRevisions of April,1977)

PAGE 17

6COMMONGROUNDthanthe31,200cubicfeetper secondofficiallyrecordedatthemouthofthecanyon.Atleastonehundredthirty-ninepeople died intheflood,andeightyeightpeople wereinjured.Theflood destroyed316homes,45mobilehomesand52businesses.Seventy-threemobilehomessufferedmajor damage. AftertheBigThompsonflood,therewasgraveresolvethatadisasterofthismagnitude should never happenagain.Thiswasparticularlytruein Boulder, whereofficialsrealizedthatthey faced a worsecatastropheifthesameBigThompsonstormmaterializedovertheBoulder Creekdrainage.DowntownLovelandisfour milesfromthemouthoftheBigThompsonCanyonandwasbasicallyunaffectedbytheBigThompsonflood;downtownBoulder, however,liesdirectlyatthemouthof Boulder Canyon. Hazard awareness followingtheBigThompsonfloodwashigh.Asimilardisasteronly fouryearsafter237liveswerelostin Rapid City servedtofocusofficialattentiononflashfloodsandwestern flood problems.Inthedecade followingtheflood,manyscientific,technological,andeducational advances have been made,andtheideafortheSymposiumgrewout of ourinterestinevaluatingthenotion ofdisasterasopportunity.InwhatwayshavewelearnedfromtheBigThompsoncatastrophe?Arewemoreorlessvulnerable?Thisquestionhasmanyfacets,andeveryoneattheSymposiumhadhisorherownperspective.TheSymposiumbroughttogetherforecasters,hydrologists,sociologists,geomorphologists, localcivildefenseofficials,utilitiesdepartment managers,stateemergency preparednessofficials,waterengineers,membersoftheinsuranceindustry,lawyers,andgeographers. Threecharacteristicsdistinguishedourgathering.First,theparticipantsweredrawnfromanextremely wide range ofdisciplinesandprofessions.Second,theSymposiumprovided arareopportunitytolook backandassessthestrengthsandweaknesses ofpost-disasterresearchandpolicyactions.Thepost-auditprovided arealeventandtime period focusforreflectiononthecommonlyheld premisethatdisastersareopportunitiesforchangetoreducelossesfromafutureevent.Third,afterwespenta day-and-ahalfdiscussingadvancementsanddisappointments,wemetonFridayafternoonandSaturday morningtomakeresearchandpolicysuggestionsfortheremainder ofthecentury.

PAGE 18

Gruntfest7Asummaryoftheresearchandpolicyrecommendations canbefound intheconcludingsectionofthisproceedings volume. We have beenabletoappraiseourprogressandidentifythoseareaswhereprogressisslower thanwewouldhope.Thesuggested adjustments can reduce ourvulnerabilitytoflashfloodlosses.HowFarHave We Come? ------------IntheBigThompsonCanyon,safeareashave beenestablishedandthecountylawenforcementofficialshavestreamlinedtheirhandling ofpotentialemergencies.Fewerstructuresarelocatedinthefloodplainbecausemanywere washedawayandfewhave beenrebuilt.Thelandacquisitionprogram, throughextensiveinteragencycooperation,has purchased numerousparcelsforopenspace.Coloradoismuchbetterprepared todayforflashflooding thanitwasin 1976.Newlevelsofinteragencycooperationwereapparentinthe1982Estes Park dam-break flood response.Theinteragencypost-disastermitigationteam provided ideasandincentivesforEstes Parktoimprovethecommunity land usetoreduce floodlosspotentialandtobeautifythecommunity.Thestatemitigationplan not only informslocalcommunityofficialsoftherange ofoptionsthey haveforflood hazardmitigation,butalsostresseshowfrequentflashfloodsareinthestate.Morethantwice asmanyColoradans have purchased floodinsurancetoday thanhadin 1976. All floodplainresidentsintheDenverandBouldermetropolitanareahave received brochuresindicatingthepossibleactionstotaketoreducelosses.Manycommunities,includingBoulder, have warning systemsnow.Several communities haveretainedprivatemeteorologiststoassistinlocalpredictionsanddataanalysis.Signs have been placedatcanyonentrancesincreasingpublicawareness oftheflashfloodpotential.ThePROFSprogram which has been developedattheNOAAEnvironmental Research Laboratoryisbeingtestedin Denver in November.IthasgreatpromisetoassistWeatherServicemeteorologists.Regional floodplainmanagementhas beenhighlysuccessfulintheDenvermetropolitanarea,andsimilardistrictsareplanned inthePikesPeakregionandonthewesternslope.Atthenationallevel,therehas been agreatervalueplacedoncooperativeeffortsamongresearchersandgovernmentofficials,variouslevelsof government,anddiversescientificdisciplines.The1978Executive Order

PAGE 19

8COMMONGROUND11988 hasmade"mitigation"nearlya household word.TheInteragencyPostDisasterMitigationTeamscoordinateteamstostreamlinetherecovery processandfacilitateanticipatorythinkingforlong-term floodlossreduction.Federalaidispredicatedonlong-term plansforreducingfuturefloodlossvulnerability.Therearemanymoreexamplesofsuccessfulmitigationefforts,includingrelocationandacquisitionprograms,andpreflood/postfloodplanning.TheAssociationofStateFloodplain Managers hasactivelyfosteredtheadoption ofinnovativestrategiesformitigation.AttheJune,1986,ASFPMmeeting inPittsburgh,officialshadopportunitiestolearnstate-of-the-arttechniquesforwarning, mapping, stormwater management,andinnovationsinhydraulicsandhydrology. ni Inspiteofthesegains,thefactsarethatmore than 200peopledieannuallyfromfloods intheUnitedStates,manyintheircars.Thissituationhas not changedmuchsincetheBigThompsonflood.Recommendations inthe1986Unified ProgramforFloodplainManagementlook remarkablysimilartosuggestions made inthe1966originalTaskForcereport.Whiletherearelocalcommunitiestakinginitiativetoreduceflashfloodvulnerability,thepressuresplacedonlocalgovernmentsbythenewfederalismseemunlikelytobeaccompaniedbythefundingnecessarytoimplementinnovativeflood hazardmitigation,especiallyin communities wheretherehave beennorecentfloods.Smaller communitieswilldisproportionatelybesqueezedsincetheyarelesslikelytohave plannersandpersonneltoenforceexistingland useregulations.Forecastingimprovementswillincreasetheprobabilitythatflashfloodswillbepredicted.However,therearemanyflashfloods over small watersheds causedbylocalizedconditions,liketherecentPittsburghfloods,andthesestormswillstillbedifficulttoanticipate.Theremaining papers inthissectionwilldescribeingreaterdetailthe1976floodandtheresponsetoit,andpapersinsubsequentsectionswilladdressmanyofthepertinentissuesrelatedtomitigation,forecasting,andwarningandresponse.

PAGE 20

STATERESPONSETOBIGTHOMPSONCANYONDISASTERKennethR.Wright WrightWaterEngineers, Inc.IntroductionTheresponseoftheStateofColorado to the1976BigThompsonCanyonflooddisasterwasoutstandingthankstotheinterestandcaringdemonstratedbyColorado'schiefexecutive, G:lvernor Lamm,coupled withmanydedicatedcivilserviceemployees.Thegovernorwasalertedto the disasterduring thenightofJuly31, 1976.Bythemorning of AugustI,the I'kleel s ofstateresponse \\ere turning.TheColorado NationalGuardwasmobilized.Thefirststateemployeesdirectlyinvolved in thedisaster \\ere thoseoftheColoradoStateHighwayPatrol. One patrolofficerlosthislife I'klile warning canyonresidentsto take to high ground.Thegovernor immediately appointedtop-levelassistantLee Wlite to thedisasterrecovery I>Ork. ByDayTwo,LarryLangoftheColoradoWaterConservationBoard(CWCB)hadcontractedforaerialphotography to surveythedamage certainty. On Tuesday,OayThree,thegovernormetinLovelandwithstate,federalandlocalofficials,allofwhomparticipatedinimportantfunctions.Supportofthechiefexecutivewascriticalin implementingmanyspecialpro grams of thereliefeffort.Fa11owingthefloodpeakandphysi cal disasteroccurrence,theColoradoNationalGuardmovedto Lovelandatthegovernor'sdirectionwithexperthelicoptercrewsandequipment. Accesswasgained to the canyonandrescueeffortscommenced.Guardsmendroppedoffbyhelicopter \\ere able to assemblevictimsataccesspointsforairrescue.Extraordinarypowersareconferredonthegovernor to "meet the dangerstothestateandpeople presentedbydisasters"under the ColoradoDisasterEmergencyActof1973. Thislegislationiswell thought outandeffective.

PAGE 21

10STATERESPONSEFivedaysaftertheflood,thegovernorappointedaspecialconsultant l'A1ose chargewastoplanandcoordinatetheoverallstateeffort.Theconsultantwasabletooperatehorizontallyacrossallstatedepartmentsanddivisionswithoutbeinghamstrungbyorganizationalchartsornormalprotocol. He reporteddirectlytothegovernor.Theeffortbythestatecontinuedatahighlevelformorethanayeartoassistthevictimsandtheirfamiliesrecoverfromthedisasterandtopl an forthefuture.Whiletheinitialactionsbythestate \\ere quickandeffectiveduetoexcellentorganizationand a widerangeofresources l'A1ich couldbebroughttobear,itwasinthelongmonthsafterwardthattheexpertiseanddedicationofstateemployeesmadeaneven moresignificantimpact.Thestateeffortinrecoverywasunified,integratedandconsistent.Do'sandDont'sRatherthanmerelyreact,thegovernordirectedstateagenciestoprovideleadership l'A1erever aprobablevacuumexistedsothattheresourcesofthestate \\Ould befullyavailabletoassistvictims.Duringthefirst \\eek, theMayorofRapidCitywasflowntoDenverforconsultations.Theobjectivewastoenhanceefficiencyandtodetermineanddefinepredictableissues l'A1ich\\Ould likelyarise.RecoveryexpertProfessorJ.E'JgeneHass,oftheUniversityofColorado,wasalsoconsultedinitially, as wasProfessorGilbertWhite.Plans \\ere laidfortherestorationandreconstructionphasesatanearlydateinconsultationwiththecommissionersofLarimerCounty andthecityleadersofEstesPark andLoveland.Alistofdo'sanddon'ts(Haas,etal,1977) waspreparedtoalertofficialstothetypeofchallenges l'A1ich\\Ould soonarise.Thislistfollows:1.Don'twaituntiltherestorationperiodisnearlyoverbeforestartingtoexamine,systematically,theupcomingreconstructionissues.

PAGE 22

Hright 112.Beginimmediatelytoconsider whether newdecision-makingmechanisms,includingthepossibilityofadvisorygroups, are goingtobeneeded.3.Doexamine, at anearlystage,theavailabi1ityofanadequatenumberoflocalspecialists who maybe neededtocarryoutrapidbutthorougheffortsearlyinthereconstructionprocess.4.Don'tassumethatdecision-makersintheprivatesectorwillholdoffontheirdecisionsuntilthemostimportantpublicpolicydecisionshave been made. 5.Ifthereistobesignificantrelocationoffamiliesorbusinesses, con siderthefullrangeofservicesneededandthefullarrayofconsequences which mayfollow.6.Rememberthatdespitethebesteffortstoshapethecharacterofthere-constructedcanyonarea,fundamentalchangeisun1ike1y.Pasttrendswi11beac-celeratedin mostcases.Designtheplanningprocesswiththisinmind.7.Don'tassumethatalltemporaryhousingwillbetemporary.8.Don'tconfusephysicalreconstructionwithrecoveryofthecanyon as awhole.9.Douseeveryreasonab1eopportunitytomakethecitysafer,butdon'tmakeinvulnerabilityanultimateobjective.10.Whentemptedtodelayanimportantdecision,don't.Goals,Objectives,PolicyTodevelopacommoneffortatalllevelsofgovernment,awrittentabulationofgoals,objectives, and policywaspreparedbythestateforconsiderationbylocalandfederalgovernment.ThiswasadoptedbytheBigThompson CanyonAdvisoryCommitteeonAugust23,1976.ThegoalsfortheBigThompson CanyonAdvisoryCommittee \>ere shortandsimple,butmeaningful. They \>ere (Wright,1977):1.EconomicandSocial-assistsurvivors,propertyowners,and cOl1lllunitiesinreadjustment.2.PhysicalandPub1icWorksProjects-recoveryandrehabilitationofcanyontobeaccomplishedinsafeandorderlymanner.

PAGE 23

12STATERESPONSE3. Planning achievepositiveresultsandavoidduplicationofpastmistakes.4. Financial -assuremaximization of planningandpublic \\Orks financialassistance.ResponseStrategyforGovernor'sOfficeStategovernment canbecumbersome,hureaucraticandslow moving. However,thiswasnotthecase l'oIlen theColoradoStateGovernmentwascalledupontoassistintherecoveryeffortin theBigThompsonCanyon.Toensurecoordinatedactionsbythenumerous departmentsanddivisionswithin thestategovernment,
PAGE 24

Wright13 As theBigThompson Canyon disasterresponsemovedfromtheemergency phaseintotherecoveryphase,itwasnotedthataleadershipvacuumtendedtoexistatthelocalgovernmentlevel.ReverendBobSchellingwasquoted intheJuly29, 1977issueoftheEstesParkTrailGazetteassaying,"The Governorreallytriedtoletthecountyruntheprogram,butthey \'.ere notreadyforthedisasterandtheycomeofflikethey'recampaigningratherthantryingtosolveproblems".Aboutthesametime,theCounty FloodCoordinatorsaid,"thetimingofthefloodrelativetotheSeptemberprimaryelectionandtheNovembergeneralelectioninLarimerCountycontributedtotheproblemofslowrecovery."Thesediscussionstookplaceduringtheperiodofrecoveryregardingwhetherlocalversusstateorfederalcontrolofrecovery isinthebestinterestofgooddisasterresponses.TheobservationsofReverendSchellingandtheLarimerCountyfloodcoordinatorwerenotfarofftarget.However,thelocalleaders \'.ere nottobl ame. Theydidwhattheythoughtwasbestatthetime.AfterlongyearsofexperienceservingthecitizensofLarimerCountyandthetwocities,thelocalofficialstookthepositionthattheyknew vmat wasbestfortheareaandforitscitizens.Theproblemsthatdidariseandwhich \'.ere manifestedbydissatisfaction,unhappiness,andasenseoffrustrationonthepartofthevictimsandtheirfamilieswerecausedbythesystem,notbythelocalofficials.Thesystemwassetupinthetraditionaldemocratic il'nerican wayofassumingthat1 oc al government sknowwhatisbestfortheircitizens. In thiscase,thelocalpoliticalleaders \'.ere thrustwithoutwarningortrainingontocenterstagefordisasterresponseeven thoughthiswouldbetheirfirstandonlysuchexperienceinadministeringanationaldisasterrecovery.Placingthelocalpoliticalleadersintothekeydecision-makingroleforrecoverywasa no-winpropositionforthem. In fact,theensuing1976primaryandgeneralelectionsinLarimerCounty wheretwooftheincumbents \'.ere upforreelectionrepresentedtheseconddisasterforthem.OnecommissionerwasvotedoutofofficeintheSeptemberprimaryelectionandtheotherwasoustedattheNovembergeneralelection. N:l matterwhattheydecided,andnomatterhowtherecoveryphasewent,thevotersreactedasifthecommissionershad beenresponsibleforthefloodanditsensuinqconfusionandhardships.

PAGE 25

14 Financiql AssistanceProvidedSTATERESPONSEThetotalfundseitherspentorcommittedasofDecember31,1977,fordisasterreliefandrelatedexpenses amountedto$57,987,441.Table1showsa breakdownofthesefunds as providedbylocal,stateandfederalgovernmentsandprivateorganizations.Tab1e1BigThompsonDisasterAssistanceSpentorCommittedasofDecember30,1977(BasedonBest AvailableFigures)Source$AmpuntFederal54,936,170State1,398,974Local684,474Private967,823Total57,987,441Technicalandphysicalassistancewasalsoprovidedinthedisasterresponse.Theseaspectsarelessquantifiable,becausetechnicalassistancemaybegiven inthedailycourseofdutiesofanagency, suchastheextensiveassistanceprovidedbythe Colorado GeologicalSurveyortheewCB(Wright,1977).FloodplainRegulationsInJuly1974(twoyearsbefore theflood),Larimer Countyjoinedthe National Flood Insurance Program,andpropertyownersbecameeligibleto purchaseinsuranceatsubsidizedrates.Atthetimeoftheflood,onlyone floodinsurancepolicywasineffectin theBigThompsonCanyonandonly23policieshadbeen purchased inallofLarimer County.OnFebruary26, 1975,theColorado Water ConservationBoard(CWCB)adopted amodelfloodplainregulation.Thatsamemonth, Larimer County adopted afloodplainregulationsimilartothatoftheewCB.

PAGE 26

ght15Thefloodplainofthecanyonhadnotbeendelineatedatthetimeoftheflood;but,fivemonthslater(December1976),preliminaryfloodplainmaps weremadeavailableforreview.TheBigThompson Canyonfloodplainwas"designated"bythestatesixmonthsaftertheflood.Itisinterestingtonotethatonlyeightand ahalfmonthsaftertheflood,wheremanyofthevictimswereovernightcampersdownclosetotheriver,theCommissionersofLarimerCounty approved useofthefloodwayinthecanyonforovernightcamping as a"usebyright."However,threemonthslater,thisapprovalwaschangedtorequireaspecialpermit.Hadthefloodplainbeendelineatedandadministered,andhadtheresidentspurchasedfloodinsurance,theentirerecoveryeffortwould have beeneasierandthefinancialassistanceprovidedtosurvivors l'.Ould have been moregenerousandeffective.Abetterpre-floodstateprogramoffloodplainmanagement l'.Ould havemadealotofdifference.ProgressinStateResponseCapabilityTheresponseoftheStateofColoradototheBigThompson Canyonfloodof1976 wasprofessional,energetic,andthorough.Thiswasduetoathoughtfulandcaringgovernorandahandfulofded icatedandcapab1estateemployeeswhoweretrai nedandknewwhattodo.Pre-floodplanningandpreparationingeneraland,specificallyforthecanyon,wasnotinagoodstateofpreparati onforboth1oca1andstategovernment.Theabilityofthestatetorespondin1986isbetterthanin1976,butisnotadequate lII1en measuredagainstthestate-widethreat.Astatecannotrelysolelyontheabilityandreadinessofachiefexecutiveas a measureofitsresponseandrecoverycapability. Nither shouldthestaterelyonahandfulofselectemployees.Botharesubjecttoretirementand movingon.Stateresponseneedstobeinstitutionalized.Pre-floodplanningisneeded.Post-floodredevelopmentplansforhazardouslocationsshouldbeprepared. Decision treesmust bereadytoavoidhavinginexperiencedlocalofficialshandleanemergencywithoutwarning.

PAGE 27

16STATERESPONSEThelegislaturemust provide adequate funding to support the \\Qrk ofthededicatedandprofessionalfloodresponsestaffoftheStateofColorado. References Haas,J.t., R.W.KatesandR.W.Bowden1977ReconstructionFollowingDisaster.LondonEngland:MIT Press. Cambridge,Massachusetts,andWrightWaterEngineers, Inc:. 1977"BigThompsonFloodDisaster,Final Report to the GovernorofColorado."

PAGE 28

SOMETHOUGHTSONFLASHFLOODPREPAREDNESSOFPUBLICENTITIESINCOLORADOBrianHydeColoradoWaterConservationBoardThe1976BigThompsonfloodshowedgraphicallythedeficienciesof the current system.Itled to short-termandsomelong-term awareness in government agencies,andtosomespecificactions.Italso fostered academic research. __Out inTimeBoulderCountyandtheUrbanDrainageandFloodControlDistricthavedeveloped warning systems.Itisclearthatradiostations,televisionstations,andthe National Weather Servicecanallhavea role in warning people (i.e.,KCOlwarning helped prevent aKodakemployeeparty in theBigThompsonCanyonthe night of the flood).The1986Pittsburgh floodhasreinforced the question of relyingongauges alone for warnings.Itseemsthatweneedtorelymoreonmeteorology to supplement or replace gauges. Asignificantproblemcanbewhattodowith the warningsothatpeople are movedtosafety.InCheyenne,peopleweretoldtogototheirbasements to avoid tornadoes,andthereby risked drowning. During theBigThompsonflood,whywereroads notmoreeffectivelyclosed to vehicles? There are severe flood warning systems in Colorado, butmanycommunities are not coveredandthereisnostatewide system. Recognizing tre ProblemAnargument frequently heardisthat"Thisisnot theBigThompsonCanyon,thisisdifferent."Debate over whether a 350-year or a10,OOO-yearflood occurred tends to reduce concern. Thereisconflictbetweena community'seconomicobjectivesandproperty owners'rightsvs.protectingpublicsafety.Sometimespublicofficialshavefinancial or otherinterestsin the flood plainwhichmayaffecttheirperceptions.Examplesinclude the use ofCDBGmoneyinManitouSprings toexpandtheirdowntown,ordirectivesfrompublicofficials"not to scaretouristsawaywiththreatsof floods. "

PAGE 29

18FLASHFLOODPREPAREDNESSAlotof floodplainmappinghasbeendone,somoreinformationisavailable.Sometimeslenders, insurance agents,andrealtorsareawareofthe problem; sometimes they are not.Westillneedbettercommunication.Somecommunitiesthatare growingrapidlyare notgettingfloodplainmapsormapchangesfromdevelopers.Itisdifficulttobeawareof hazardsifyourmapsare out ofdate.Thereisa tendency to focusattentiononsnowmeltfloods instead of consideringallpotentialcauses. Serious problemshavelargelybeencausedbythunderstorms. Regulating theFloodPlainThetwomostcommondeficienciesin local administration of NationalFloodInsuranceProgramregulationsare out of datemapsandaninadequate or nonexistent permit system.Alllevelsof governmentneedtodohetterhere.Animportant questiontoaskishowlocal governments(largeandsmall)canobtain technicalexpertiseto evaluate landuseproposals inflashflood areas.Manycommunitiespreferstructuralapproaches to floodmitigation.Iffuture conditions are not considered in designingsuchfacilities,problemscanarisedueto increased flowsfromincreased urbanization.Structuralapproacheshavetheirlimitations;theycan'talwaysfixeverything. Existing development cannot alwaysbeprotected.Communitiescould considerstructuralapproachesasonecomponentin a comprehensive program.Theabilityof flood-proofing or actualstructuresto withstandhydrostaticandhydrodynamic forcesisnot addressed in flood plainregulations.Emergencyresponse plans for evacuating buildings inflashflood areas are not usually required.Asgrowth occurs,howwillweknowhowsafe a locationis?Howmanypeople in theBigThompsonCanyondied incampgroundsoronroads or bridges?Whatkinds of regulationsdoweneedformotorhomefacilitiesandcampgrounds, bridgesandroads?

PAGE 30

BUILDINGONADISASTERRobertL.Kistner Colorado Division of DisasterEmergencyServicesTheearlydawnof July15,1982,brought adefinitechange to theTownof Estes Park, Colorado, a mountaintownlocated30miles northwest of Boulder ataneleva tion of 7,700feet.LawnLakedam,locatedatanelevation of 11,000feet,12miles to theeastof Estes Parkfailed,sending817acrefeetof waterdownthe Roaring River throughRockyMountainNational Park into Fall Riverandthen Estes Park.Thefloodingwasbrief,lastingonly afewhours, but of unprecedentedseverity.Itwashedawaybridges, destroyed road systems, a hydroelectricplant,astatefishhatchery, inundated177businessesand108residences,andcaused three deaths.OnJuly 19,1982,the Governor of Colorado requestedthata majordisasterbedeclared for theLawnLakeDamfailureandFall River flood in Larimer County.OnJuly22,1982,the President of the UnitedStatesdeterminedthatthe floodingwasofsufficientseverityandmagnitude to warrant aMajorDisaster Declaration under PublicLaw93-288. LarimerCountyandtheTownof Estes Parkweredeclaredeligiblefor federalassistance.Asthe flood waters receded,shopowners, volunteersandtownclean-upcrewsbeganthe job of renewing Estes Park towhatithadbeenbefore thedisaster.Thetownhired a professionaldisasterrecoverymanagerto coordinateallof the reconstructionactivities.Townofficialsrealizedthatintergovernmentalrelationswouldprobablybea highpriorityduring theinitialstage of reconstruction decision making,especiallyifthedisasterwasof the magnitude of theBigThompsonFlood.Anobviously important element of intergovernmentalrelationsfor Estes Park officialswasthe process of obtaining federal grants to supplement theeffortsandavailable resources of Estes Park, theStateof Colorado,andvariousdisasterrelieforganizations.Atthesametime a group of businesspeople organized theForwardEstes Park Foundation(FEPF)tousethedisasterasanopportunity to rebuild a"new"Estes Park.TheFEPFhadactuallybeenorganizedearlierin1982,whena group of14business leaders in EstesParkcontributed 51,000 each, incorpor ated,andbeganto study theeconomicproblems of the Estes Park area.

PAGE 31

20BUILDINGThetowndiscoveredthatwithin apresidentially-declareddisasterarea,statelawmakesitmucheasiertocreateanUrbanRenewalAuthority than inmorenormaltimes.TheFEPFpressured thetownwith the idea ofcreatingthe Estes ParkUrbanRenewalAuthority(EPURA).TheTownBoardonSeptember 14,1982created theEPURAandproceeded with thecreationofadowntownimprovementplan. A Boulder planning firmwascontracted to prepareanUrbanRenewal/DowntownRevitalizationPlan for thetown.Atthesametime theUrbanRenewalactivitywasunderwaythe clean-upfromthe floodwasproceeding, including the reconstruction ofIIbridges.AlongFall River, propertyownerswererequestingassistanceintheirrebuildingefforts.Several of thegreaterthan50%flood-damaged buildingswerenot allowed torebuildduetonewfloodplainregulationsadoptedbythetown.Manyof thestructuresdestroyed in the floodhadbeenconstructedpriorto floodplainregulationsandwerecantilevered out over Fall River.Insomecases the corners of buildingswerebuiltinto the stream, with the only corner support being aconcrete-filled55gallon barrel anchored into the stream bottom.Thedisasterrecoverymanagerassistedbusinessownersin obtaining 1,362 NationalFloodInsurance Grantstopurchasedamagedpropertiesandreplace thestructureswith parksandopengreen space.InMayof1983the completedUrbanRenewal/DowntownRevitalizationPlan, with a suggested development time-frame of20years ormore,waspresented to thetown.Theplan proposed:1)Toeliminate theexistingconditions of botheconomicandphysicalblight2)Throughnewcommercial developmentandredevelopment,newopportunitieswillbeprovided to strengthen Estes Park's economic base3)Todevelop implementation plansandstrategiesforthedowntownarea to guide, enhanceandencourage the developmentandredevelopmentofthe areabyjointprivate/publicpartnerships4)Toinsurethatdevelopmentandredevelopment willbesensitiveto,andprotectsurrounding areas,andthat...relocationofexistingresidentsandbusinessesbefairandequitable5)Todevelop apedestrian-orientedActivity Center,whichwillcreateavisually...attractivedowntown

PAGE 32

Kistner216)Todevelop a planthatwill encourage the use ofalternativetransportationmodesintoandthroughout thedowntownarea.Theseshould includeshuttletransit,pedestrian, equestrian,andbicycle uses7)Toeffectivelydevelopandenhance the natural beauty of the streamsandriversflowing through thedowntownarea, while...providing formoreeffectiveflood protection measures8)Toencourage the conservation of energy resourcesatalllevelsof use9)Toimplement the adopted Estes Park Comprehensive Plan toassistthe orderly growth of the Estes Park area.Fundingthe ProcessInDecember,1983,theTownBoardadopted a tax increment planforfinancingEPURAprograms.Thetownwill receive thefirst$949,790 ofsalestaxandtheEPURAwill receiveallmoniesabovethatmarkupto a proposedcapof $400,000 each year within the designateddowntowndistrict.Sales tax revenue for theEPURAthefirstyeartotaled$88,732, the second year $212,287,andthethirdyear,1986,$368,429.Theincreases areduemainly toanincrease inretailsalestieddirectlytobeautificationof thedowntowndistrict.Total expenditures for thetwophases ofstreetscapingexceeded $1,000,000.Theextrafundswereobtained in loansandgrantsfromthetown.Nofederaldollarswereusedinanyof the urban renewalprojects.Townfiguresshowthatnet taxablesaleshaveincreasedatafasterratein the urban renewal area(URA)than in thetownasa whole:28%within theURAinthelast30monthsvs.23.5%in the remainder of thetown.Severaltrafficmodifi cationshavebeenmade,including realignedintersections,betterturning lanes,andaone-waystreetsystem. Since theURAwascreated,atleastsixmajor building renovationshavetaken place in the coredowntownarea.SummaryEstes Park "Buildingona Disaster"istaking place beforealltowitness. AdisasterastragicastheLawnLakeDamfailureandflashfloodhasuncovered opportunitiesfordevelopmentandredevelopmentthatcould notbeachievedbyothermeans.Thebusinessandpoliticalleaders of Estes Park are tobecommendedfortheirdedication.

PAGE 33

THETEMPORARYMORGUEOPERATIONMichaelCharneyForensic Science Laboratory ColoradoStateUniversityTheidentificationofthe victims of theBigThompsonfloodwasa success inthatall139bodieswereindividually,positivelyidentified.Thisisthe onlymassdisasterthathas occurredwhereallthedeadweresoidentified.Thisisalso the onlymassdisasterwhere, tomyknowledge, the necessaryscientificpersonnelcametogetheratthe verystartof thework:a forensicpathologist,a forensicodontologist,a forensic anthropologistandlawenforcement agents expert in dermato glyphics.Intwoprevious papers (Charney,1978, 1980),Idealtatsomelengthonthe organization of the temporarymorgueatBigThompsonCanyon.Receiving, holding,andeventual evacuation of the bodies; records, missing persons,bodyexamination, dentalandfingerprintwork,supplies, psychologicalandreligiouscounseling,vitaistatisticsandother suchsectionsformedquicklyandeasily.Athirdpaper (CharneyandWilber,1980),gavesomedetailsasto the techniques, asdentalrestorations,sinusprints,earcomparisons,andradiologicalcomparisons, A major problem confronting the successful,scientificoperationofa temporar) morgueisthe lack ofanystatutesorregulationsto determinejustwhoisresponsiblefor theidentificationofunknownhumanremains. Thisvacuum,ifImayviolatephysical lawsandirritatethespiritsofNoahWebsterandBenJonson,relatesto both individual instances ofunknownremainsandto multiple deaths inmassdisaster.Thetaskofidentificationistaken overbythe local coroner or medical examiner.Howevercompetent withintheirownexpertise,whichcouldbepathology ordentistry,nooneissufficientlycompetent inallareas necessary for individualidentification,particularlyin the case of multipledeaths.Toassumesuchexpertiseiseitherintellectuallyarrogant orplainstupid or both.Sucha person harbors a"QuincyComplex"that,unfortunately,isalltooprevalent.Theconcept of ateamapproach tobodyidentificationisnotminealone butwasvoicedbyRealsandCowan(1979)aswell. Theirswasthe sad task ofidentifyingthe victimsofthe Teneriffe crash,wheremorethanhalfof thesome350deadwere neve

PAGE 34

Charney23identified.Tomyknowledge,noanthropologistwasemployed. Ihadbeenaskedtomakemyselfavailablebutthatwasall.Thepersonnel of a temporarymorguemustincorporatemanypeople, including:1)Threeforensicscientists:apathologist,odontologist,andanthropologist.2)A keeper of records. Thisroleisessentialifanythingistobelearned for futureanalysis.TherecordsattheBigThompsonwereadisasterin themselves. Iwasgiven to believethattheheadof oursectionwasin hospital records,whichwastrue--butonlyasatranscriber.3)Communications: atightcontrolofallincomingandoutgoing telephonecalls.AttheBigThompsonwehadnocentralswitchboard.With20-odd telephonesathand,manyof the volunteers gave out information theywereneitherqualifiednor authorizedtogive.4)Psychologicalservices.Families waiting for information about the missingcomeinallemotionalstates.Manyare inneedof sympathetichandling.Theclergyandthe local county mental healthofficeplayed amostprofessionalroleattheBigThompson.Welearnedfromexperiencethata dutyrosterofsuchpersonnelwouldhavehelpedtoavoid"feastor famine" during the threemonthsof operation.Manyothersectionsof a temporarymorguewillfallintoplaceandoperate without fuss, suchasfingerprintingashandledbythe locallawenforcement agency. or the storageandhandling of the bodies,whichwasdonemagnificentlybytheLovelandPolice ReserveattheBigThompson.Therehavebeendozensanddozens of conferences following theBigThompsondisasteronjusthowto prepare for anothersuchevent.Allsortsof peoplehavebeeninvited toparticipatein these conferences, the majority ofwhomtooknopart in theBigThompsondisasterandwhoseinterestswereoften onlytangential.Iwasinvited to onlyoneandthenasjustanafterthought.Allen, the forensic pathologistof ourteamwassimilarlyignored. Surely, thosewhoran the only successfulidentificationof the dead of amassdisastershouldhavesomeinput in conferences dealing withmassdisasters.Intheten years since theBigThompsondisaster,stepshaveprobablybeentakentoanswersomeof the questionsraisedbysucha cataclysmic event, but theidentificationof the deadhasseennonewlight.Idonotknowofasingleconference,symposium,ortalkthathasaddressed the problemssuchidentificationsraise.TheproblemisnotjustColorado's or Larimer County's alone,itis

PAGE 35

24TEMPORARYMORGUEnationwide.In1980andearlierIcalledfor asymposiumtobeheldonthissubject.Onesuchconferencewasheldin1967atthe SmithsonianInstitution,butitonly addressed thescientificquestions. Anewsymposiummustalso address the administrative questions.Justwhoshouldmakeuptheteamofidentifiers?Tocontinue to allowthisdecisiontobemadebythe local coroner and/or medical examineristo perpetuate adisasterallitsown.References Charney,Michael1978"TheTemporaryMorgueandtheIdentificationof Bodies." Police Chief45,pp.10285-10288.1980"OisasterPlanning:Organizat ionandOperationofaTemporaryMorgue."Police Chief47(#4),pp.66-67. Charney,MichaelandCharlesG.Wilber1980"TheBigThompson."AmericanJournal of Forensic MedicineandPathology 1 (#2),pp.139-143. Reals,W.J.andW.R.Cowan1979"Forensic PathologyandMassCasualties."HumanPathology 10,pp.133-136.

PAGE 36

PARTTWOMITIGATIONMEASURES

PAGE 37

ThispageISblank

PAGE 38

POLICYCHANGESAFFECTINGTHECORPSOFENGINEERSFLOODDAMAGEPREVENTIONPROGRAMBorySteinbergU.S.ArmyCorpsof Engineers IntroductionForthe past15years, therulesunderwhichtheU.S.ArmyCorpsof Engineers flood controlprojectshavebeenformulatedhavechangedsignificantly,resultinginrecommendationsofsolutionsthataredifferentfromthose proposed in the1950sand1960s.Theguidance theCorpsoperates underisbasedonfederallawandmajor policy statements promulgatedbyExecutive Orders,OMBCirculars, PrinciplesandStandards, PrinciplesandGuidelinesandEngineer Regulations.Aswecelebratethe 50th anniversary of theFloodControlActof 1936,itisappropriatethatweevaluatehoweffectivethe federal flood controlprogramshavebeen.WeintheCorpsareproudof our record in floodcontrol.Ourprojectshaveprevented over5150billionindamagewithaninvestment of about$23billion.Asidefromthe untold sufferingthathasbeenavoided, the paybackrateismorethan seven tooneand,onaverage, theratioisincreasing. Yet, theworkisnot complete. Floods continuetoplaguecertainareasofthe country, but not necessarily thesameareasasthosenowsafefromthe ravaging floods of the 1930s,40s&50s.Inordertounderstand the changesthathaveoccurred since enactment ofNEPAandmostly since the mid-1970s, abriefreview of the federal involvement in flood control helpssetthe stage forwherewe've been,whereweareandwherewe're going.Likemanyother current functions of the federal governmentthathavebeeninexistence for anumberofyears, the importance given to aprogramgoesthroughpeaksandvalleysandtakesonvaryingprioritiesin the budget process.Thetypes of solutionsmostcommonlyusedmayalsogothrough periods ofgreateremphasisononetype or another.TheCorpsflood controlprogramcertainlyhasseen substantial changesandisin the process ofanevenmoredramaticchangeasaresultofnewcost sharing formulas.

PAGE 39

::::28"----"C.=-c0RPS OFENGINEERSPolicyChanges]listasthe changes having thegreatestimpactontheCorpsflood controlprogrambetween]970-1985 the following: Enactment of the National Environmental ProtectionAct(NEPA)Useof higher discountrates Projections of sounder decisions in the floodplainEmphasisonnon-structuralsolutionsDegreeofprotection:NationalEconomicDevelopment(NED)Plan vs. Standard ProjectFlood(SPF)vs.Affordability Highercost-sharingEnactment of the National Environmental ProtectionActAnincreased concern with the environmentandtheNEPAprocesswerebuttwoof the reasons for thevirtualhaltin the formulation of multiple purposereservoirprojects.Reservoirprojectshadbeenformulated, authorizedandconstructed for over30yearswhenNEPAwaspassed. Planning guidance ineffectin1970urged theCorpstomaximizeopportunitiesfor comprehensive development. Nevertheless, thenumberofnewreservoirprojectsrecommendedandfundedover the past decadehasbeenextremelylimitedandinmostcases municipal water supplyhasbeenthe driving force behind thefewnewprojects.A review ofnewCorpsconstructionprojectsfundedbyCongressbetween1978ana1984revealsthatof the54projectsfunded,26wereflood controlandonlyoneof the26projectswasareservoirproject.This compares with themorethan50newreservoirprojectsfunded for constructionbetween1970-1977.*Veryfewnewreservoirsare included in pending authorizinglegislation.*]tisclearthatotherfactors(suchashigher discountrates,assumption of sounder decisions in the floodplain,anddeletionofcertainbenefitsfromtheeconomicanalysis,aswellasmorevocal oppositionfromupstream land owners) besides environmental concernsresultedin a lack of broad support forreservoirprojects.However,oppositiononenvironmental groundswasa majorfactorin thevirtualelimination of majorreservoirsasasolutionto flooding.

PAGE 40

Stei nberg29Useof Higher Discount RatesThediscountrateused in formulatingnewprojectshasrisenfrom3-1/4% in1969to 8-5/8% in 1986.Theresulthasbeenthatexpensiveprojectsthatrequire future growthhavenotbeenjustifiedandprojectsprovidingmodestprotection toagriculturalorruralareashavebeendifficulttojustify.Furthermore,thesizeofprojectsproducing theNEDplanhasgenerallybeensmaller than those formulatedona 3-1/4% discountrate.Reservoirprojectswith major flood controlbenefitsat8-5/8%havebeenextremelyrare.Aninterestingphenomenonisthatasthe cost of government borrowing dropsbelow8-5/8%, the drop in the discountratecanonlybereduced.25%per year.Thus,the discountratewill continue tobeasignificantandlimitingfactorin the formulationoffutureCorpsprojects.Projections of Sounder Decisions in theFloodPlainPriorto1973,benefitsfor protection of future development inanarea being consideredfora flooddamagepreventionprojectwerebroadlycalculated.Corpsplanning guidance permitted inclusion ofbenefitsattributableto:1.Prevention ofdamageto additional developmentanticipatedduring the period ofeconomicanalysisevenifflood protectionwerenot provided.2.Developmentpotentialcreatedbytheproject,normallyresultingfran changes orintensificationin landusemadepossiblebytheproject.Inevaluating thesebenefits,thewithout-projectconditionswerelefttothe discretionof theCorpsplanners.Forexamp1 e, theassumeddevelopmentof land in the floodplainwithout theprojectmayhavebeenreasonable based upon experience elsewhere or baseduponmarket pressures forcertainland uses.However,theviewgrewthatsuchdevelopment mightactuallybean unwiseuseOf the floodplain.Therecognitionthatannual lossesfromfloodswereincreasing. whileatthesametime the development of property with exposureto floedda,Ti?; being financedtoa degreebythe federal government, led to enactl1llellt ofthe Fl,D'Q'() Disaster ProtectionActof 1973.Onepurpose of theactistorequirestates or local communities,asa condition of future federal financialassistance,toparticipatein the flood insuranceprogramandtoadopt floodplainordinances effectiveenforcement provisionsconsistentwith federal standards. If local

PAGE 41

30CORPSOFENGINEERSordinances are not enactedandenforced, the floodplainswillbemorevulnerablein the future than ourprojectionspostulate.TheCorpscontinued to allow thecalculationofbenefitsbaseduponfuture developmentuntil1975. Engineering RegulationER1105-2-351, dated13June1975,supersededER1120-2-113 and, ineffect,prohibitedCorpsplannersfromincluding future flood controlbenefitsin the flood plainwhennotconsistentwithstrategiesfor floodplainmanagementandtheFloodDisaster ProtectionActof 1973. Thissignificantchange occurred becauseitwasassumedthattherewouldbestrategiesfor floodplainmanagementthrough the adoptionandenforcement of land use regulations.Thewithout-projectconditionisbaseduponthe assumptionthatindividuals will undertakecertainmeasuresanywayto reduce flood hazardsbyfloodproofing or elevatingnewstructurestoatleastthe 100-year floodlevel.Thismeansthatundeveloped landonthe fringes ofanurban areamaybeassumedtobedeveloped in thefutureasappropriate.However,byproviding floodprotection,the only benefitthatmaybeclaimed withinanareathatformerlywaswithin the 100-year flood plainisthe savings in floodproofing orelevatingofstructureswhichwillnolongerbeneeded with a flood controlproject.Thebasic assumptionisthatanydevelopment in vacant land within the 100-year floodplainwith aCorpsprojectwouldbecompatible with Executive Orders11988and11990andPublicLaw93-234.EmphasisonNonstructural Solutions Despite a concertedeffortto developnonstructuralsolutions,theresultshavebeenminimal--although a higher grade for procedureisprobably deserved.Ananalysis the authormadeofmorethan170flood controlnewstartssince enactment ofNEPAindicatedthatin only threeweremajor nonstructural components included.Thesemeasures includedrelocationfromdeveloped floodplainsaswellasacquisi tion of floodplainlands toprohibitfuture development orforoverbank storageandrecreationin caseswherethe flood plainissparsely developed. There aremanydifficultiesinjustifyinganonstructuralprojectandin obtaining the necessary local supportandfinancing.Inresponse to the question"Whatdoyouseeasimpediments toCorpsimplementation ofnonstructuralmeasures?" posed todistrictoffices,themostcommonproblemscitedwerelack of local cooperation or acceptance,andeconomicfeasibility.Nonstructuralsolutionsinvolvingrelocationor floodproofing are very personal measures.Itisdifficultto convincehomeownersresidingathigher elevationsthattheirtaxdollarsshould

PAGE 42

Steinberg31beusedtohelppayfortherelocationof peoplewhousedpoor judgment in residinginthe floodplain.Experiencehasshownthatsomepeople arewillingto accept theriskof periodic flooding given thealternativeof being asked tomove.Several reasons are given forthisreaction.Onehastodowith the federal flood insurance program.Whereperiodic floodingstillleaves thehomehabitable,theownerscanlook forward to periodic upgradingfrominsurance payments. Another reasonisthe tendency for individualstocomparethebenefitsthey derivefromanonstructuralprojectwith those oftheirneighbors. Peopleresidingatslightlyhigherelevationmaynotbeincluded in therelocationplan yetmaystillbesubjecttoflooding, since the relocatedstructuresmayonly involve those in the10-to IS-year floodplain,or floodproofingmayonlybeto the 10-year stormelevation.DegreeofProtection:NEDPlan vs.SPFvs.AffordabilitvSeveral yearsagoitwascommonin urban areas,whentherecommendedsolutionwasa high floodwall or levee, to increase the level of protectionabovethatwhichwouldmaximizeneteconomicdevelopmentbenefits.Theconceptwasto provide protectionagainsta standardprojectflood(SPF)storm.AnSPFstormisdefinedasthemostsevere flood-producingrainfalldepth/area/durationrelationshipforanystormthatisconsidered reasonablycharacteristicof the region inwhichthe drainage basinislocated,giving considerationtothe runoffcharacteristicsandexistence of waterregulationstructuresin the basin.Ineffect,the floodwall designed to provideanSPFlevel of protectionwasgenerally the200-SOO-yearflood standard, while the NationalEconomicDevelopment(NED)plan mighttypicallybeat the 100-year level ofprotection.Current policystressesproceeding with theNEDplan unlessjustificationforanexceptionisapprovedatthe Assistant Secretary of theArmylevel.MostprojectsrecommendedarenowNEDplans; however,weare findingthatthe nonfederal sponsormaywellbeconsidering aprojectprovidinglessthan theNEDplan, foreconomicreasons. There obviouslyisagreaterriskwhena sponsordesiresalesserdegree ofprotectionandwecarefullyevaluate our designaswellastheriskbefore agreeing to proceed in each case.Itissometimes acceptable to buildprojectsinstages, basedonthe nonfederal sponsor'sabilityto financeitsshare,aslongasphased constructionispracticalfromanengineering viewpoint.However,the level

PAGE 43

32CORPSOFENGINEERSof protection considered acceptableforagriculturalareasisnot acceptable in urban areas. Higher Cost SharingThusfar,basedon41newstartsthatwereaddedbyCongress in afiscalyear1985Supplemental Appropriation Act,wehaveobserved aclearcut willingness of sponsors to signupfor the highercost-sharingbut notnecessarilyfor theprojectrecommendedbytheCorpsunder previous cost-sharingrules.Inthe case of floodcontrol,thereare several instances of phasing construction basedonaffordabilityandthe timing of thenonfederal sponsor's financing plan.Therealtestwillcomeon"second generation"projects,whereeXisting conditionsconsistof aprojectproviding50-to100-yearprotectionandtheCorpsproposes amuchhigher degree ofprotection.Intheseinstances,thecostin cash to thenonfederal sponsorsisgenerally high. Since the requirement for additional lands, easement,andrights-of-wayisfrequentlylow(generallylessthan10%),the requirement to reach25%requires a higher level of cash.Thetestwillcomewhenweare ready to undertake construction ofsuchprojectsasWyomingValley, Pennsylvania,wheretheexistingprojecthasbeenadequate forallstorms except one--the exception beingAgnesin1972,whentheprojectwastotallyinadequate. Anotherexampleisthe SantaAnaRiver Project inCalifornia,whichhasbeenprotectedbyPradoDamanddownstreamchannels, butwhichwouldbeinadequate in the event of a major flood. FutureEmphasisGreater PartnershipRoleCost-sharing offeasibilitystudiesandprojectdesignandconstruction will bring theCorpsandthenonfederal sponsorsclosertoa partnershipratherthananexpert-clientrelationship.Thelikelihood of studying flood problems forwhichtheCorpscannotjustifyaneconomicallyfeasiblesolutionearlyin the study will diminish,aswill the degree ofeffortonsolutionswhichare not supportedbythe nonfederal sponsors. Staging of constructionandrequests toconstructlessthan theNEDplancanbeexpected to increaseandinalllikelihoodwillbehonoredwheretheriskisacceptabletoboth the federal governmentandthenonfederal sponsor.

PAGE 44

Steinberg33Reallocation of StorageTheCorpshasconstructed over300majorreservoirprojectswith flood contra storage.Asdemandsformunicipalandindustrialwater supplyincrease,wecanexpectsignificantlymorerequests for conversion of flood control storagetomunicipalandindustrialwater supply storage.Theconcept of having vendable products inCorpsprojectsisattractivebut needs tobeevaluatedagainstthe aspect of flood controlbenefitsforegone. Generally, however, serious proposals t: reallocatestorage for water supply willbehonoredifthe sponsoriswillingto pal the appropriatecosts.FloodWarningSystems Heretofore theCorpshasnotrecommendedprojectsthatconsisted exclusively of flood warning systems.Warningsystemshavebeenincludedasanonstructuralelement inmorecomprehensivestructuralandnonstructuralprojects.Wearenowonthe verge of amajDrbreakthrough in th is area. Arecommendationfor afloodwarning system in the Passaic River Basin,NewJerseyisbeing given serious consideration, with approval expectedshortly.Theimportance of the stand-alone flood warning systemprojectisthatitisresponsive where, for avarietyof reasons, theCorpshasfailedtoprovidestructuralprojectsandnonstructura1 despiteyearsofstudy.ThePassaic River BasinhasbeenstudiedbytheCorpsfor several decades withvirtuallynoprojectshavingbeenimplemented, despite the dense populationandfrequent flooding. Perhapsitisthe multitude ofpoliticaljurisdictionswithin the basinthathascomplicated reaching a consensusonsolutionstothe flood problems. GreaterStateParticipation As federal programs provide a smaller percentage of overallcosts,thenonfederal sponsor willbeexpected to bear agreaterburdenofresponsibility. In caseofflood controlprojectswecanexpectgreaterparticipationby the statesto upthedifference.Theimplicationisthatthestateandlocal sponsors also wi11 haveagreaterinterestin the planformulat i onprocess.

PAGE 45

34CORPSOFENGINEERSReferences Steinberg,Bory1984"FloodDamagePrevention Services of theU.S.ArmyCorpsof Engineers:AnEvaluation of PolicyChangesMeasuring AgainstCriteriaof Equity, EfficiencyandResponsiveness".DPAdissertation,GeorgeWashington University. Presentation ofFloodControl Estimates in Survey Reports.U.S. U.S.Congress1973FloodDisasterProtectionActof 1973. Senate Report583toAccompanyHR8449, 93rd Congress,1stsession.1985Supplemental Appropriations Act.PL99-88.1986AnActtoProvide for the ConstructionandDevelopmentofWaterandRelated ResourcesandtheImprovementandRehabilitationof the Nation'sWaterResourcesInfrastructure.HR6, 99th Congress. Department of theArmyCurpsof Engineers1968Engineer Regulation 1105-2-113: BenefitandHurricane Prevention Washington,DC1975Engineer Regulation 1105-2-351: Evaluation of Beneficial ConstructiontoNationalEconomicDevelopmentforFloodPlainManagementPlans. Washington,DC1983SummerProceedings: Implementation of Non-Structural Measures. Ft. Belvoir,VA:InstituteforWaterResources.U.S.President1977Executive Order 11988.FloodPlainManagement.May24.U.S.WaterResources Council1979Final Rule. Procedures for Evaluation of NationalEconomicDevelopment(NED)BenefitsandCosts inWaterResources Planning (Level C). Federal RegisterIX,Vol. 44,No.242.1983EconomicandEnvironmentalPrinciplesandGuidelines forWaterandRelatedLandResources Implementation Studies. Washington,DC:U.S.GovernmentPrinting Office.

PAGE 46

PERSPECTIVESONTHEBIGTHOMPSONDISASTER--THENANDNOWJeromeM.OlsonNaturalandTechnologicalHazardsDivision FederalEmergencyManagementAgencyIwouldliketocommentonthe mitigationstrategiesemployedin1976in the aftermathoftheBigThompsondisaster,andquickly review the mitigationprogramswhichare in place in1986within the FederalEmergencyManagementAgency(FEMA).This chapter concludes with recommendations for the future. Mitigationstrategiesduring theweeksandmonthsfollowing theBigThompsondisastercanbecharacterized in these terms: Minimumguidance.Therewerenoproceduresonflood hazard mitigation,asidefromminimalflood plainmanagementregulations. Strong leadershipfromGovernorLammandtheCountyCommissionersimmediately following thedisaster.Maximumcollaboration. Variousstateagencies, the county,andthe federal agencies united in theFloodHazardRiskStudyandthe land acquisition program. Sense of mission.Changesinlandusepatternswouldnothaveoccurred without the understanding of county,state,andfederalofficialsthatthistragedymustnotbepermitted tohappenagain.Inreviewing ourfilesonLarimerCountyandthedisaster,the threecriticalactivitiesthatsurface are: theFloodPlainManagementMoratorium, theFloodHazardRisk Study,andtheLandAcquisitionProgram.Thechangesinthe landusepattern in thecanyonfromresidentialandcommercialtoopenspacecanbeattributedto the successfulinteractionamongtheseactivities.I believeitwouldbeofinterestto reviewsomeof the eventsanddecisionmakingprocessesthatoccurredintheweeksandmonthsimmediately following thedisaster.BackgroundWhenthe flood occurredonJuly 31st, LarimerCountywasin theEmergencyPhaseof the NationalFloodInsuranceProgram,meaningthataFloodInsuranceStudyhadnot yetbeenconductedandtheFloodPlainManagementRegulations requiredbythe

PAGE 47

36PERSPECTIVESFederal Insurance Administration(FIA)wereminimal.Infact,theBigThompsonCanyonwasnotmappedasa SpecialFloodHazardAreaona FloodHazardBoundaryMapissuedbyFIAinEmergencyProgramCommunities. Fortunately,wehadjustsigned acontractwith Gingery Associates in June to conduct a flood insurance study,sotheamendmentprocesstoinclude thecanyonwassimplified.Wehadnothadthewisdomtoinclude thecanyonin theoriginalscope of study.Ourrationalehadbeenthatthecanyonwasalready developedandtoo sparselysettledto conduct acost-effectivestudy. believe thesignificanceofthisisthatnotallflood hazard areas willbeidentified,evenafter10years ofstudies.Obviously, our oversightwastobecorrected quickly,particularlyaftera meeting with oursisterfederal agenciesonAugust4thanda meeting with GovernorLammin thecanyononAugust 6th.TheBigThompsonwasdeclared a Federal DisasterAreathemorningofAugust2nd,andonAugust4th Iwasinvited to a federal coordination meeting sponsoredbythe FederalDisasterAssistance Administration.Atthe meeting I suggested to the agenciesthatthey shouldrequirethe purchase of flood insuranceasa condition oftheirfinancialassistance,pursuant to theintentof Executive Order11296onFloodPlainManagementandPL93-234, theFloodDisaster ProtectionActof 1973.Thereactionfromthe federal agencieswaslessthan overwhelming.Theagencies took thepositionthatsince theBigThompsonhadnotbeenidentifiedasa SpecialFloodHazardArea, theywereundernoobligationto require flood insurance.Whiletheirinterpretationmayhavebeenlegallycorrect,itwasnotconsistentwith theintentof the Executive Order.Theimmediate concern of theagencieswasresponseandrecovery.Myreactionwastoinitiatethe issuance of a FloodHazardBoundaryMaponthecanyontobringPL93-234 into force. Since the issuanceofthemapdid not require aFloodInsurance Study,itcouldbeproducedbytheFIAin a matter ofweeks.FIAwasvery responsiveandissued themapin September.OnAugust 6th, a group offederal,state,andcountyofficialswasinvitedtoaccompanyGovernorLammonafieldreconnaissance ofBigThompsonCanyon.Viewingthe devastationatDrake, the governor turned tomeandasked,"Whatcanwedoto preventthisfromhappening again?" 1hadnoready response, but I did not forget the question.Fourdayslater,the LarimerCountyCommissioners asked the governortousehisemergencypowersto authorizeLandUseControlsanda Building Permit Moratorium.Themoratoriumwasto apply to the areas within the high watermarkfor a period of

PAGE 48

Olson37sixmonths.Thepurposescitedfor the moratorium were: to permit completion of the floodplainstudy, tocomplywith county flood plainregulations,andto protect thehealth,safetyandwelfare of currentandfuture inhabitantsandusers of property along theBigThompsonRiver.TheFloodHazardStudy, conductedbetweenAugustandDecemberof1976, repre sents a highly cooperativeeffortonthepartof the ColoradoWaterConservationBoard(eWCB),Larimer County, the Colorado Department ofHighways,andthe Federal Insurance Administration.FIAprovided the majority of the fundingandparticipatedin 19.1 miles of flood hazard analysis.Thecountyandthe Department ofHighwaysprovided funding to develop contour intervalmappingbeyondthe scope of thetraditionalFloodInsurance Study. Since the countyandthestatewereparticipatingin the cost of the study,itwasalso possible tobemoreflexiblein the technical approachestothe hydraulic analysis.Forexample,weincluded afloodwaybaseduponstatedepthcriteriaratherthan FIA's surcharge,andwealso considereddebrisload in the analysisatbridge openings.Anadditionalsixmiles of streamwerestudied, usingstateandlocal resources.TheCWCBagreedtopublish theFloodHazardReportuponcompletionofthe engineering. Thiswasnecessary since federal regulations require appealandconversion procedures of approximatelyoneyear forFloodInsurance Studies. Obviously, the recoveryeffortrequired the studymuchsooner.Thefirstpublic hearingonthe flood plain delineationswasheldDecember22,1976.I believethatthe cooperationandflexibilitydemonstratedbytheentitiesinvolved in the studyhada verypositiveeffectuponthe study process.InlateNovemberthe federal coordinatingofficercalledmyattentionto a newspaperarticleintheLovelandReporter-Herald(November18,1976)thatidentifieduncontrolled development occurringinthe canyon.Thearticlewentontostatethatcanyonresidentswereupsetbytherestrictionsonbuilding permitsandthattwoCountyCommissionerswerehaving serious misgivings about the moratorium.Inanefforttodetermine thefactsandtoremindthe commissioners oftheirresponsibilityto control development within flood hazard areas, I wrotetothecommissionchair,requesting information. Within days Iwascontactedbythe newspapers inLovelandandFt. Collins tocommentonmyletterandthe county'sresponsibilitiesfor flood plainmanagement.Quoting Senator Hartandmyself, the Fort Collins Coloradoan reportedonDecember1st,ontheirfront page,that

PAGE 49

38PERSPECTIVESsuspension of the countyfromthe NationalFloodInsuranceProgramforfailureto regulate development couldhavea seriouseffectuponthe recoveryeffort.Senator Hart expressed concernthatthe reported uncontrolled developments could jeopardize federal funds for rebuilding the canyon.Ironically,Commissioner Michiewasscheduled tomeetwithmethesameday.Wehada very amicable meeting inwhichheassuredmethatthe county intended to regulate the floodplain.TheColoradoan reportedoneweeklaterinamuchsmallerarticle,onpage20,thatanunderstandinghadbeenreachedandthe countywasnot in danger of suspension.Itismyunder standingthatpoliticalrelationshipsbetweenthestateandthe countywerealsoatrock bottomatthispoint. Obviously, considerable pressurewasbrought to bear against the county to maintain the moratoriumwhichtheyhadadoptedsoquicklyafterthedisaster.A study published in1979bytheWesternGovernors' Policy Office concludedthatflood insurance appeared tobethekeytoanyprogramoflossreduction.amnot convincedthatthe decisionmakingisthatstraightforward. Rather, insuranceisonefactorincomplexinterpersonalandintergovernmentalrelationships.TheBigThompsonCanyonFloodStudywascompletedonschedule inDecember,andmeetingswereheld with theCountyCommissionersandcanyonresidentsbeginningonDecember22,1976.TheCWCBdesignated the study in mid-Januaryandthe county adopteditonJanuary31st.Theimpact of the studywastoprohibitmostreconstructionwithin the area devastatedonJuly 31st.Itisdoubtful whetherrestrictionscouldhavebeenmaintained without a landacquisitionprogram.Atthatpointintime, publicofficialswerenotcertainwhereacquisitionfundswouldbesecured. A newspaperarticledated January 14,1977,reportedthatLarimer County's flood coordinatorandtheInterfaithDisasterRecoveryTaskForcewerejoining together to preparelegislationfor land acquisition tobepresentedtothe Colorado GeneralAssembly.Giventheshortfallinstaterevenues,the appropriationwasanuphillbattle.InApril, theU.S.Houseof Representatives approved RepresentativeJamesJohnson'samendmentto the FederalLandandWaterConservationActto permit the purchase ofBigThompsonlandatpreflood valuations.Justificationforthisapproachcamefromthefloodwayprovisions prohibiting reconstruction. Iwouldaddthatthe language of theamendmentimpliedthatthefloodwayprohibitionswerebasedonthe NationalFloodInsuranceProgramrequirements.Suchwasnot the case. Finally,onDecember13,1977,SenatorFloydHaskell'sofficereported therelease

PAGE 50

Olson39of $747,600bythe Secretary ofInteriorto permit theacquisitionof156acresinthe canyon. Total expected acquisition costswerein excess of $2,025,000.Theadditional revenueswerederivedfromtheStateof Colorado, Larimer County, theU.S.LandandWaterConservationFund(Colorado apportionment),andtheFourCorners RegionalCommission.Twoyearsafterthedisaster,the countywasstillengagedinthe recovery processandland acquisitionwasongoing. Althoughmanyroadblocks existed in theacquisitionprogram, I believethatitcanbedemonstratedthatitwaslargelysuccessful in changing the land usefromresidentialandcommercialtoopenspace,consistentwith the flood hazard. I believethatoneadditionalcharacteristicwecanascribetothe decisionmakingprocess following thedisasteristhe willingnessonthepartofmanypublicofficialsto take arisktoimprovecanyonsafetyandpreventthistragedyfromhappening again. Current Approaches toFloodHazardMitigationSomuchhasbeenpublished since theBigThompsondisasterontechnical standardsandprocedures for nonstructural approaches to flood hazard mitigationthatitisdifficulttodojusticetothesubject.Instead, I willbrieflydescribesomeofthe currentactivitieswithin the FederalEmergencyManagementAgency.FederalEmergencyManagementAgencyFEMAwasformedasanindependentagencyin1979,combining programs adminis teredbythe Federal Insurance Administration, theU.S.Fire Administration, the Federal Disaster Assistance Administrationandthe Civil Defense Programs.Theexpressed purpose of theagencyistopromotetheemergencyresponseandhazard mitigationcapabilitiesof the federalgovernmentin areas of natural hazardsandcivildefense.Thenatural hazard mitigationresponsibilitiesare divided in the regionbetweenthe Disaster AssistanceProgramsDivisionandthe NaturalandTechnological Hazards Division. Disaster Assistance Programs--MitigationDAPhas approacheditsresponsibilitiesfor hazard mitigationseriouslywith the publicationofproposedrulesinApril of1986toclarifyimplementation ofits406responsibilitiesunderPL93-288andthe InteragencyHazardMitigationTeamsasrequiredbythe OfficeManagementandBudget.Asdefined in the regulations, a406

PAGE 51

40PERSPECTIVESHazardMitigation Planisa systematicidentificationofpolicies,programs,strategiesandactions tobecarriedoutbystateandlocal governments tousethe legalauthorities,financialcapabilities,andpoliticalleadershipavailableto reduce or avoid long-termvulnerabilitytohazards.TheInteragencyHazardMitigationTeamsare convened, immediately following apresidentialflooddisasterdeclaration,with the expressed purpose of producing areportwithin15daysthatidentifiesmitigationopportunitiestobeconsidered in the immediate recovery process.Asanaside,thisteamapproachisadirectoutgrowthofa National Science Foundation studyentitled"LandUsePlanning After Earthquakes,"whichwasreviewed in Boulder in1979following the Natural Hazards Conference.DAPhasalsoliberalizeditsfunding under the Public AssistanceProgramtopermit fundingupto15%of theDamageSurvey Reporttopromotedisaster-proofing.inaddition,DAPisproviding fundstothestatesunder the DisasterImprovementGranttopromote hazardmitigation.Currently,DAPadministersLhe1362ProgramfundedbytheNFIP,the purpose ofwhichistoacquire flood-insuredstructuressubjecttorepetitivedamage.RegionVIIIDAPhastaken a very aggressive approach in promotingtheirhazard mitigationresponsibilities.NaturalandTechnological Hazards DivisionTenyearsandnearly$1billionlaterinFloodInsurance Studies, theemergencyPhaseofthe NationalFloodInsuranceProgramisdrawing to aclose.TheFederal Insurance Administratorhasmadeacommitmentto CongressthatallnewFloodInsurance Studies willhavebeenstartedbySeptember 30,1988.WithinRegionVIII,virtuallyallnewstudieshavebegun.Asaresultweare entering anewphase in theprogramthatconcentrateslessuponthe conversion of communitiestotheregularprogramandmoreuponthe techni calassistanceaspects of hydrologic engineeringandfloodplainmanagement.

PAGE 52

THENATIONALFLOODINSURANCEPROGRAMACCOMPLISHMENTSANDDIRECTIONS1976-1986 DouglasGoreFederal EmergencyManagementAgencyTheNational FloodInsuranceProgram (NFIP)wascreatedin1968toidentifyfloodhazards,establishlocalfloodplainmanagement programsandprovideaffordablefloodinsuranceprotection.Today,asaresultofNFIPactivitiesofthepastdecadefloodhazarddata,localfloodplainmanagement programs, and floodinsurancearecommon-place innearlyevery community inthenation.Significantlessonsin hazardmitigationcanbelearnedfromtheexperienceoftheNFIPin accomplishingtheseobjectives.Understandingthese1 essons involves a reviewofboththeaccompl ishments anddirectionsoftheNFIPintheareasof1)Flood HazardIdentification,2) Local FloodPlainManagementPrograms,and3)FloodInsurance.Flood HazardIdentificationTheidentificationofflood hazardareasbytheNFIPrepresentsthelargestundertakinginthehistoryofwaterresourcemanagementtodevelop anddisseminatefloodhazardinformation.Sincetheprogram's beginnings in 1968 through 1984,theNFIPdevelopedfloodhazardmapsfor18,667 communitiesatatotalcostof$654.2million.Identifyingflood hazardareasisessentialtotheoperationoftheNFIPfor(1)definingthenatureandextentofflooding,(2)asthetechnicalbasisforlocalfloodplainmanagement programs, (3)fordetermining wherethepurchaseoffloodinsuranceisrequiredand (4)forsettingNational FloodInsurancerates.Importantly,thepresenceofsuch dataalonecreatesan awareness, concern andresponsibilityforfloodissuesatthelocallevel.Further,thestructureoftheNFIPmakestheuseofNFIPflood hazarddataamatterofspecialinteresttolocalgovernmentofficials,home-buyers,lenders,insuranceagents,developers,engineers,architects,realestateagentsandothers.This wideacceptanceanduseofNFIPfloodhazarddatarelatestoanumberoffactorsincludingthetechnicalstandards

PAGE 53

42andmethods for conducting flood insurance purchase requirements,NFIPinsurancestudies,theNFIPmandatory floodandNFIPcommunitycoordinationactivities.Thetechnical standards for flood insurancestudiesarealmostidenticaltowhattheywereten years ago.TheNFIP,forexample, maintainsthebase(1%frequency or 100-year) flood event astheprogram's standardandconsequently as the basis for local flood plain managElTlent programs. Althoughthisstandardwaswidely a'cceptedbyfederalandstatewater resource agenciespriorto theNFIP;suchwasnot the caseatthe locallevel.Today,oneseldomencounters argumentsonwhether or not the base flood standardisappropriate, althoughmanycontinue to misunderstanditandincorrectlydefineitas the flood occurring onlyonceeveryone-hundredyears.Inaddition to the base flood, flood insurancestudiesalso continue todefinethe10, 50,and500-year flood elevationsandregulatory floodwaysnotexceeding the one-footrisecriteria.Thestandards for preparing flood insurancemapswerechangedslightlyonlyrecently.TherecentNFIPMapInitiativesProjectresultedin modifiedmapstyl es in response to opinions expressedbyuser groupsformakingflood hazardmapsmoreeasilyreadandhopefully, as aresult,moreused.Thenewstyleincludes placing floodway dataonFloodInsurance RateMaps,makingthisdataavailabletoinsurance agentsandlendersforthefirsttime.Anevengreaterapplicationof flood informationmayresulthowever,fromthe newly-introduced County-wide (vs. community-wide)mappingformat. Thislatterinnovation increasesthepotentialforaddressing flood issuesonamulti-jurisdictionalbasis.Mostof thescientificmethodsfor conductingFloodInsurance Studiesusedatthe commenCElTlent of thelastdecade continue to represent the best methodsavailable.TheHECII methodology developedbytheU.S.ArmyCorpsof Engineers,forexample, continues tobethe dominant methodology formoststudies.Theuse of recognized,"stateof theart"methods producing reasonably accurateresultsiscriticaltothecredibilityandacceptance of the program.Oneonlyneedsrecallthe laok ofNFIPacceptance in the mid-1970's followingthemasspublicationofFloodHazardBoundaryMaps(FHBMs)basedonapproximate methods to recognize thevalidityofthispoint.Interestingly,thegreatestfrustrationsmostoften expressed by users of flood hazard informationrelatesnot to thevalidityof technical data butratherhowitisgraphicallypresentedonmaps.Issuesrelatingto whether or notanindividual propertycanbeidentifiedas in or out oftheflood plain(mapscale,basemapcontourintervals,aerialphoto basemaps,etc.)oftenloomaslargerconcerns than pure technical accuracy or methodology.

PAGE 54

Gore43TheNFIPmandatory flood insurance purchase requirements enacted in1973contribute,perhapsmorethananyotherfactor,tothe adoption ofNFIPflood hazarddata.Therequirement to purchase flood insurance, as a conditionforobtainingfinancialassistancetobuyreal property located in flood hazardareas,actuallycreatedinterestin the program.Onlywhenflood hazard informationbecamerelatedtoeconomicconcernswasthereanywide-spreadinterestin flood hazarddata.Theenactment of mandatory flood insurance purchase requirementswascoupled provisionsforimprovedcommunitycoordination betweenNFIPrepresentativesandlocalcommunityofficials.Thisrequireslocalofficialsbekeptfullyinformed abouttheNFIPandlocal flood insurancestudiesthrough public meetingsandothercontacts.Mostimportantly,NFIPrepresentativesdirectlyassistlocalofficialsin developing flood plainmanagementordinancesforadoptingandimplementing flood insurancestudies.This follow-upassistanceprovided to everycommunityenteringtheregularphase oftheNFIPexceedsthatprovidedbyotherflood study programsandisin part responsibl eforthehigh local adoptionrateof flood insurancestudies.Thegreatestchallenge in the area of flood hazardidentificationismaintainingtheaccuracyoftheflood hazard data developed todate.Without restudyandmaprevisionprograms the technical basis for theNFIPwouldbeobsolete in afewyears.Thereisacriticalneedto obtain revised flood hazard datawhenevermodifications to floodplainsoccur. Frequently, channelizationprojects,bridgesandflood controlstructures,etc.,significantlyalterfloodingcharacteristicsrepresentedbyNFIPdata.Unfortunately,newdataisnot always submitted toinitiateNFIPfloodmaprevisions.Agreatereffortisneededto assure localofficialsunderstandtheirresponsibilityto review technical datareflectingfloodplain modifications before approving such developments. A second challengein the area of flood hazardidentificationisresponding to requestsformorespecialized flood hazarddata.TheNFIPcurrentlyappliesuniform standardsandmethods tomostallflood insurancestudiesdeveloped. Thiswasessentialintheearlyphases oftheprogramin providing technical dataforthethousands of communitiesestablishingfloodplainmanagementprograms.Now,however, as communities gain experience in usingthisdata,limitationsinthestudiesarerealized.Consequently,thereisanincreasingdemandformoreprecisedata as well as informationonunique hazards such asflashfloods,risinglakes,allUVialfans,mudflowhazards,dambreak,etc.Thereisalsoa growinginterestin obtaining technical dataonstorm waterrun-offandlocal drainage problemswheretheNFIPpays

PAGE 55

44NFIPclaims but does notidentifyhazards.Further,thereisaninterest,once hazardsareidentified,to seekstudiesoneliminating flood problems including flood controlstudiesandmaster drainage plans.Whilethereisreluctanceandpossiblestatuatorylimitationsto pursuingstudiesotherthantraditionalflood insurancestudiessucheffortsprovideopportunitiesformeetingNFIPobjectives.Theyalsomaybemorecosteffectivein meetingNFIPobjectivesthan payingforrestudiesandrepetitiveclaims.Lastly,asthecomputer informationrevolutionintensifies,therewillbeanincreasingdemandforcomputerized flood hazard dataandgraphics over papermapsandstudies.Thisnewtechnology will also provideanopportunitytofacilitateflood hazardmappingandrevisions.LocalFloodPlainManagementPrograms Establishing local flood plainmanagementprogramsisacriticalcomponentoftheNFIP.Itwaslong recognized only throllghthereduction offuturepropertyatriskcould a national flood insuranceprogrambeactuariallyfeasible.Thisisnecessary to avoid thecostlysituationofsubsidizing,andthereby encouraging, additional unwise flood plain development.Communityeligibilityforthesaleof NationalFloodInsurance dependsuponadoption of local ordinances,consistentwithNFIPcritieria,toprotectfuturenewconstructionfrommajor flooddamage.Nationally,thethousands of floodplainmanagementordinancesnowineffectwereeitherenacted or strongly influenced because ofNFIPrequirements.Presently,17,654 communitiesarequalifiedtoparticipatein theNFIPbecause oftheirlocal floodplainmanagementordi-nances.Thefloodplainmanagementstandards forcommunityNFIPparticipation,as outl inedbyNFIPregulations(Titl e44CFRpart60.3), remain fundamentally unchanged duringthelasttenyears.Inbrief,thesestandardsrequire:1) a permitforallfloodplaindevelopment, (2)theelevation ofthelowestfloorofallresidentialconstructionandmanufactured housingtoor above the base floodlevel,(3) theelevationor dry floodproofing ofallnon-residentialconstructionto the base flood leveland(4) prohibition of floodway development unlessitisdemonstratedtherewillbenoincrease in the base floodlevel.Therearemanyreasonsforthelargenumbersof communities accepting these standardsandlocal floodplainregulationasthestrategyfor floodloss

PAGE 56

Gorereductionandas a requir61lent forNFIPparticipation.First,NFIPstandardsareadministeredlocally,ratherthanbythefederal government. Second,ordinance adoptionisoneof thefewfloodlossreductionstrategiesinvolving anominalpub1iccost.Third, theNFIPstandardsformanagingfutureflood plain developmentdonot impactexistingdeve10p:nent. Fourth,NFIPstandards provide a balance between developmentandfloodplain manag61lent interests.Lastly, as previously discussed, local acceptancealsorelatestothequalityofNFIPflood hazarddata,theNFIPmandatory flood insurance purchase requir61lents providinganeconomicincentiveandNFIPcommunitycoordinationactivities.Thesuccess of theNFIP,however, depends not onlyonlocal adoption ofthesestandards buta1so,moreimportantly,onlocal enforc61lent. Theeffectiveness of local ordinance enforc61lent in achieving floodlossreduction however, should notbemeasuredtotallybythepresence or absence of ideal ized floodplainswhereinitialregulatoryf100dwaysremain forever undevelopedandfloodplainsareoccupied onlybyelevated or f100dproofed building"s.Thepresence of flood hazard dataandflood plain manag61lent ordinances,ifproperly en forced,actascatalystsforstimulatingalternativefloodlossreductionstrategiesincludingstructuralapproaches such as channelizationandleveeprojects.Whileonthesurfaceitappearstheordinancewasignoredwhensuch solutionsare imp161lented, itshou1dbe r61l61lbered theordi nance's presencecreatedtheneedforthealternativestrategy,45On-site reviews of local flood plainmanagementprogramswereinitiatedin1978asCommunityAssistanceandProgramEvaluations(CAPEs)andarenowreferredto asCommunityAssistanceVisits(CAVs).A comparison oftheresultsof these reviews duringthepast nine years inFEMARegionVIII provideinsightsontheprogress inthisarea.Theearlyreviews revealed a lack of awareness of theNFIPandlocal responsibi1ityfor enforcingnewlyadopted flood plainmanagementordinances. Frequently, localofficialscharged with enforc61lent responsibilitiesdid nothavecopies of flood insurancestudiesandmapsandwereunfami1iarwith the community's ordinanceandNFIPstandards.Morerecent reviewsindicatefami1iaritywith these basictoolsandaninterfacewith the local building permit process though administrationisoftennotfullyconsistentwithNFIPstandardsandinterpretations.Thisismost apparentwhenf100dwayencroachmentsandwatercoursealterationsareinvolved because of limited local

PAGE 57

46understandingofthefloodwayreviewprocessandNFIPfloodmaprevisionprocedures.Thisisunderstandablebecauseofthelackofdirectionontheseprocessescontainedinlocalfloodplainmanagementordinances(includingtheNFIP modelordinance)andthe1imitedguidancefromothersources.WhileprogressinimplementingNFIPfloodplainmanagementstandardsimprovedduringthepastdecade,greaterassistanceisneededtostrengthenlocalcapabilityinthisarea.NFIP Themajorchallengeintheareaoffloodplainmanagementisfindingthebestapproachesforincreasinglocalcapabilitytorespondtotheincreasingsophisticationoflocalfloodplainmanagementissues.Enhancinglocalfloodplainmanagementcapabilityisacontinuingchallengebecauseofthelargenumberofparticipatingcommunities,thehighturn-overrateatthelocal1eveland1imitedtechnicalassistanceresources.Currently,theNFIPreliesupon CommunityAssistanceVisits(CAVs) and CommunityAssistanceDeliverySystems(Stateandfederaltechnicalassistance agencies) forenhancinglocalfloodplainmanagementcapabilities.Intheory,thisapproachreliesupon communityvisitsbyagencyrepresentativestoidentifydeficienciesinlocalregulatoryprogramsandthendeliversanyassistanceneededbeforethedeficienciesbecomecomplianceissuesjeopardizingcommunityNFIPparticipation.Thewholefocusofthiseffortisonhowwellcommunitiesenforcefloodplainmanagsnentregulations.Thesuccessoflocalfloodplainregulatoryprogramshowever,representsonlyapartofthefloodplainmanagementpicture.Asecondmajorchallengeinvolvesstrengtheningtheregulatoryapproachandpromotingsupplementalfloodplainmanagementstrategiesatthelocallevel.First,communitiesconcernedabouttheregulationoffloodplaindevelopmentarefindingNFIPfloodplainmanagementstandardsincompleteinaddressingtheiruniquehazardsorsituations.The numberofcommunitiesseekingguidanceindevelopinglocalregulationsexceedingNFIP minimumrequirementstailoredtomeetcommunityneeds,isincreasing.Second,thelocalregulationofnewfloodplaindevelopmentalone,evenwithproperenforcement,isinsufficienttosolvelocalornationalfloodproblems.Thisistruebecausethisstrategyaloneignorestheproblemsassociatedwithexistingfloodplaindevelopment,aswellasthesupplementalfloodplainmanagementopportunitiesavailable.Itisalsointerestingtonote,theU.S.ArmyCorpsofEngineershasdemonstratedthecosteffectivenessofelevatingbuildingsinfloodplains(theprimaryNFIPregulatorytechnique)isdependentuponflooddepthfrequencyrelationshipsandisnotnecessarilytheoptimaltechniqueineverycommunity.

PAGE 58

Gore47Ideally,a community's floodplainmanagementprogramwouldconsistofthebest combination ofmultiple,cost-beneficialtechniquesforfullymanagingitsflood hazards.Thepublication,A Unified NationalProgramfor Flood PlainManagement,1istssixteenmajor floodplainmanagementstrategiesincluding floodplainregulations,developmentandredevelopmentpolicies(including master planningandlandacquisition),disasterpreparednessandassistance,floodproofing, floodforecasting,warning systemsandemergencyplans,damsandreservoirs,dikes,leveesandfloodwalls,channelalterations,high flowdiversions,land treatment measures,on-sitedetention measures, informationandeducation,andflood insurance.Theneedforstrengthening theregulatoryapproachandpromoting supplementalstrategieshaslongbeenrecognizedbytheNFIP.Duringthepast decade theNFIPinitiatedandsupported severalstrategiesforachieving increased floodlossreduction.Someof theseinitiativesresultedinspin-offprogramsnolongerdirectlymanagedbytheNFIP.Themostnotable examples include:PresidentialExecutive Order 11988,theInter-AgencyAgreementonPost-DisasterFloodHazardMitigation Planning, the Floodplain Property AcquisitionProgram(section 1362),theStateAssistance Program, theFEMADamSafetyProgramandthepublicationoftechnical documentsonvarious floodlossreduction techniques.TheNFIPmustcontinuallyevaluatetheproper balancebetweenpromoting supplemental floodplainmanagementstrategieswithitstraditionalmission ofidentifyingflood hazardsandestabl ishing localregulatoryprograms.Inanyevent,theNFIPwillneedto providemorecomplextechnicalassistanceas theprogramcontinues to mature.NFIPeffortsin pursuitofoptimal floodplainmanagementwillrequiregreaterexpertiseonthepartof agencyrepresentativesandenhancedteamworkin applying engineeringandplanningskillsin solving flood plainmanagementproblems. Lastly,thiseffortwillrequireincreased abilitiesinworkingwith localofficialsin demonstratingcost-effectiveness,andin fundingandimplementing floodlossreductionstrategies.FloodInsuranceTheavailabilityofaffordableflood insuranceisa major accomplishment oftheNFIP.TheNFIP,infact,wascreated withthisasitsforemostobjective.Currently,therearenearly two-mill ion insuredpropertiesfor over $139.3billion in coverage.Inaddition,since the program's inception in 1968, over $2.4billion

PAGE 59

48NFIPwerepaid in flood insurance claims representing asignificantsavings indisasterassistancepayments.Thebasic concepts of National Flood Insurance remain unchanged duringthepast decade.EligibilHyforthe sal eofflood insuranceandtheNFIPmandatory flood insurance requirementsarestillthe primaryincentivesfor local governmentNFIPparticipationandenactment of local floodplainmanagementordinances. Astatuatorychange(knownastheEagletonAdmendment)tosection202(b) oftheNFIPto allow conventional financinginthefloodplainsof communities notparticipatingin theNFIPhadrelativelylittleeffectonthe program.Whilethe fundamentals remain unchanged,thereweresignificantchangesrelatingprimarily tothemarketing of NationalFloodInsurance.Inthepast ten years these include: a doubling ofthepolicy base, insurancerateincreases,basement coverage exclusion,multipledeductibles,a national marketingcontractor,Flood InsuranceClaimOffices(FICOs)atthesitesof majordisasters,out-reachtrainingworkshopforagentsandlenders,a stream-linedratestructure,animprovedagent'smanualandthe WriteYourOwn(WYO)program.Themajor challengesareinmakingtheNFIPself-supportingwithout governmentsubsidiesandincreasingprivatesectorinvolvement. Secondarily, insurance incentivescouldbeused to agreaterdegree to accomplish theNFIPfloodplainmanagementobjectives.Theremaybeopportunities,forexample, to reward communities implementing supplementary floodlossreductionstrategiesthrough reduced flood insurancerates.

PAGE 60

GoreReferences Federal Emergency Managenent Agency1981Flood HazardMitigationHandbookofCommonProceduresInteragencyRegional HazardMitigationTeams. Septenber 1981.491984"Property,Crime, and FloodInsurance."IncludesexcerptsofPub1icLaws90-448,91-152and 93-234. Revised through Novenber 8,1984.1984 RiskStudiesComp1etionand Full ProgramStatus,FederalInsuranceAdministration,Washington,D.C. Septenber, 1984. 1985MapInitiativesProjectFinalReport.FederalInsuranceAdministration,OfficeofRisk Assessment, Washington,D.C.January1985. 1985 Flood Insurance StudyGuide1inesandSpecificationsforStudyContractors.Federal InsuranceAdministration. Septenber 1985. 1985"TheNational Flood Insurance Program'sCommunityAssistanceProgram Manual." Federal InsuranceAdministration,OfficeofLoss Reduction. October1,1985. 1985 National Flood Insurance ProgramandRelatedRegulations.44CFR.RevisedasofOctober1,1985.1986 AUnifiedNational ProgramforFloodplain Managenent. FEMA100.InteragencyTask ForceonFloodplain Managenent. March1986. 1986 National Flood Insurance ProgramCommunityStatus,InsurancePolicyandClaimsStatisticalData.MicrofischeRecords through 1986.U.S.ArmyCorpsofEngineers 1978 Physical andEconomicFeasibi1ityofNonstructura1 FloodPlain Managenent Measures.HECResearch Document.U.S. DepartmentofHousing and Urban Deve10pnent 1978 "Mandatory Flood Insurance Purchase Requirenents." FederalRegister,Vol.43No.34-Friday,February17,1978.U.S.Water Resources Council 1978"Floodplain Managenent Guidelinesfor Imp1enenting E.O.11988."43FederalRegister6030February10,1978(Reprint).

PAGE 61

THEDAMFAILUREHAZARD;AWARENESSANDPREPAREDNESSINCOLORADOByJackTrubyColorado Division of DisasterEmergencyServicesDamsafety,nowbeing developed through bothstructuralandnonstructuralmeans,isavitalprogramin Colorado.Itisparticularlyimportant to residents of LarimerCountyandtheBigThompsonCanyon.Theintegrityof severaldamswasof great concern during theheavyrainswhichbroughtontheBigThompsonfloodandduring theLawnLakeDamfailure.Thisdamfailureoccurred in nearbyRockyMountainNational Parkandthreatened theOlympusDamatEstesParkas wellascanyonresidents.Intheory,ifallnecessarystructuralmeasures to reduce thevulnerabilityof Coloradans are taken,fewifanynonstructural stepswouldbenecessary. Sinceitisunlikelythatwecanachieve perfectdamsafety throughstructuralmeansalone, a variety of nonstructuralmeanscanbeemployedto lessen potential impactsonthemanyColoradanswhocurrently reside indaminundation zones.Awarenessofthe potential for floodsfromheavyrainfall,damfailureorbothisessentialtoriskreduction. Innovations in insurance systems(particularlyNationalFloodInsurance)andzoningmethodswillcertainlyreduce futurerisklevels.Butinviewof theexistingprobabilitiesthatdamswillfailandthatvery high losses areinevitable,thereisanurgentneedfornonstructuralsteps to stimulatethreatawarenessandthe development of warningandevacuation plans for thosewhoreside in potentialdamfailureinundation zones. Untilthishasbeenaccomplished,risklevelswillremainunacceptably high.Thepurpose ofthischapteristo:1.Better define the nonstructural aspects of thedamfailurehazard in Colorado,2.Analyzeandpromotepublic awareness ofthishazard,and3.Promotethe development ofeffectivewarningandevacuation plans for threatened elements of Colorado's population.Awarenessstimulationandplanningcanbestbedevelopedlocallywithstateassistance.Bothshouldbecloselyidentifiedwith hazardandcapabilityconditionsthatarelocallyexistent.Centralizedstateeffortcandevelopmanyfeatures of

PAGE 62

Truby51the program but, in the end, productsmustbebasedonlocal conditions, flow through local systems,andbesponsoredlocally.Progresscanbestberealizedthrough apublicityprogramdirectedatthose threatenedandthose responsible for governmentalreaction.Ifthe formercanbemotivated, thelatterwill follow.Stateassistanceshouldbechanneled through local preparednessofficials.Thenpublicityandplanning elementscanbedevelopedandcoordinatedsothatthey mature intandemandsothatpublicandgovernmental cooperationhavethe best opportunity to develop inconcert.Localradiostations,newspapers,andbrochures are the bestmediatoreachandinfluence elements of the populationmostconcerned with thedamsafetyissue.Public ServiceAnnouncementtapes, brochuresandarticlesforlocal newspaperscanbedevelopedbystatestaffstobemodifiedbylocalofficialsandpresentedby them tothe media. Important awarenesstargetsare:residentsof inundation zones, the emergencymanagementcommunity,educatorsandstudents, the handicapped, lendingandinsurance agencies, past victims, volunteerreliefagencies, businessesandmanyothers.Also,stateassistancetolocal governmentscanencouragejointinterjurisdictionalandinteragencyparticipation.Progress insomelocalitiesacross thestatecanbeusedtoinfluence slowermovingentities.Within Larimer County, thetownof Estes Park,andtheBigThompsonCanyon,awareness ofdamfailurehigh; theLawnLakeDamfailureisstillinmind.However.therestof Coloradoisnotmovingatanacceptable pace. Until considerablymoreprogressismadein bothstructuralandnonstructuralmeansforimproveddamsafety.damfailureflooding will remainoneof Colorado's very highriskhazards.Insummary,the following nonstructural measures should be undertaken thnmgh out thestateassoonaspossible: Localentities(towns,cities,counties) inpotentialinundation zones should stimulate awarenessandcomplete local warningandevacuation planning;daminundationzonemanagementprograms should evolve. Thestate'sprogramtoassisttheseentitiesshouldbeexpeditedsignificantlythrough the Division ofDisasterEmergencyServices(DODES),in coordination with thestateengineer, when additional fundingisobtained. A hazard mitigation program,suchasbuyingupopenspace, shouldbeconsideredbythelegislature;suchaprogramshould operate through andsupport theinitiativesof localentities.

PAGE 63

CHANGESINOURUNDERSTANDINGOFMITIGATIONWilliamP.Stanton ColoradoWaterConservationBoardWhatMitigationWasMitigationisthenounformof"mitigate."ThewordmitigatecameintouseduringMiddleEnglish (1150-1475).Itisderivedfromthe Latinword"mitigutus,"whichisthe pastparticipleof "mitigare,"meaningto soften. Webster providestwodefinitions:1)to cause tobecomelessharsh orhostile,and2)tomakelesssevere or painful (Webster, 1974).Thehistoryof the application of measures to mitigate flood lossesisalivewith examples.Itbegins withTheDeluge, about2957B.C.,whenNoahbuiltanark.TheChinesehavebeenbuilding leveesbyhandto control the flood waters of theYellowRiver forcenturies.InMarch,1543,DeSoto's expedition in search of goldandsilverhadto wait near themouthof the Arkansas River for about amonthbefore they could proceedbeyondthe Mississippi River. DeSoto's party notedthatOnaccount of these inundations of theriverthe peoplebuilttheirhousesonthe high land,andwherethereisnone,theyraisemoundsbyhand,especiallyfor the houses of the chiefs...(HoytandLangbein, 1955). After the January,1762floodontheOhioRiver, the engineeratFortPittinPennsylvaniarecommendedelevation of thefortto protect thepowdermagazine. Following the1785floodonthe Mississippi Riverwhichinundated thetownofSt.Genevieve, Missouri (founded50yearsearlier),a decisionwasmadetomovetheentiretownto high ground.InApril,1795,aftera floodonCoveCreekandthe Nolichucky River in Tennessee, thefatherofDavyCrockett(whowaseight years oldatthe time) decided not to rebuild his cabinandmillatthesamesite.Notto leavemyAustralian friends out ofthispicture,inMarch,1817,following floodsontheNepeanandHawkesburyRivers inNewSouthWales,GovernorLachlan Macquarie issued"GovernmentandGeneral Orders"whichencouraged thesettlerstoremovetheirresidencesfromthe floodmarks to the townships. Ifirstheard of the term "flood mitigation"whenmybossestoldmetorunupto EstesParkfollowing theLawnLakedamfailureof July15,1982.Myassignment

PAGE 64

Stanton53hadsomething todowith being thestaterepresentativeonthe federalpostdisasterinteragency intergovernmental hazard mitigationteam.Iwastoldthatmyroleasthestate'sfirstmitigation personwouldbetomakejudgmentsoninsurance claimsandto"betough."Inthedaysthatfollowed, IcarefullyreadFEMA'sHandbookofCommonProceduresandfound"hazard mitigation" definedasamanagementstrategyinwhichcurrent actionandexpenditures to reduce the occurrence or severity of potential flooddisastersare balanced with potential lossesfromfuture floods (WrightWaterEngineers, 1981). Thissoundedamazingly close to atermIhadpreviously learned as "floodplainmanagement":to reduce thedamagingeffectsof floods, preserveandenhance natural valuesandprovide for optimaluseof landandwater resources within the floodplain.Itsgoalistostrikea balancebetweenthe values obtainablefromtheuseoffloodplainsandthe potential losses to individualsandsocietyarisingfromsuchuse(U.S.WaterResources Council, 1981).WhatMitigationisNowFEMAdescribes mitigationasoneof four elements of awholespectrum of governmentalactivitiesassociated with natural hazardsthatFEMAhaslabeled "comprehensiveemergencymanagement."Theother three elements are preparedness, response,andrecovery. "Mitigationrefersto actions to reduce or eliminate the adverseeffectsoffuture hazard events,"anditisbeing toutedasable to break the cycle of repeated destruction. MitigationhasmorerecentlybeendefinedbyFEMAas:anyaction taken to permanently eliminate or reduce the long-termrisktolifeandpropertyfromnaturalandtechnological hazards(RalphM.Field Associates, 1985). Obviously mitigationactivitiesmaybeundertaken before oraftera hazard event occurs.WhileFEMAestablishes postflood hazard mitigation teams, thereisnoreasonwhypreflood mitigationteamsor plans could notbecreated.TheFloodHazardMitigationPlanfor Coloradoisstatewide in scopeandaddressesfederal,stateandlocalprogramsthatdeal with flood hazard mitigation. Preflood hazard mitigation planshavebeenprepared forDeBeque,SilverPlume,andManitouSprings.

PAGE 65

54MITIGATIONOrganization of MitigationStrategiesInthe 1930s, the term "flood control"meantanSCSorCorpsofEngineersdam.Inthe progressofwater resource development inthiscountry, "flood control benefits"wereandarestillidentifiedaspart ofmostwaterprojects.Inthe 1960s, theCorpsof Engineersbegantalking about "flood loss reduction"andflood plainmanagement.Still,confusionexistsabout the scope of flood plainmanagementevenattheWaterConservationBoardwhereIworkintheFloodControlandFlood plainManagementSection. Variousschemestosortout thewiderange of mitigation measureshavebeendevised.Themostcommonare: preventive vs. corrective measures, or structuralvs.nonstructuralmeasures.Thebasic underlyingprincipal,however,istousea combination of measuresthatattempt to control water or reduce thevulnerabilityof people initspath.Theliteratureaboundswith chartsanddiagramsthatattempt to categorize the elements of thesetwobasicstrategiesintosomelogical order.Someof the bestexamplesarefromtheU.S.WaterResources Council, the DepartmentofHousingandUrbanDevelopment, the Tennessee Valley Authority, theArmyCorpsof Engineers, the State of Victoria, Australia, theNewZealand NationalWaterandSoil Conservation Authority, theAmericanInstituteof Architects,andthe ColoradoWaterConservationBoard.Current FederalEmphasisonMitigation Federalandstategovernmentsmustdeal with the cumulativeeconomicimpacts ofdamages.Theconcept of mitigation begins with the federal government,whichisina position tokeeptrack of the increasingriseindamages.Theideaofmitigating thesedamagesfiltersdownto localgovernmentandcitizens,whoseconcept of mitigationisprimarily influencedbythe federal government'smostcurrentemphasisonsoftening the losses tomakethemlesssevere or painful. Although achangein leadershipandrecently proposedamendmentsto the rulesandregulations appear to putmoneybehind anewmitigationinitiativeona nationallevel,FEMA'scurrent organizational chartshowsa disturbing emphasisoninsuranceandplaces mitigation in a subordinaterole.TheHazardMitigationBranchisbut

PAGE 66

Stanton55oneoftwobranches of the Public Assistance Division,whichisoneof three divisionsofthe Office of Disaster Assistance Programs,whichisoneof threeofficeswithin theStateandLocalProgramsSupport Directorate,whichisoneof the fourdirectoratesandtwoadministrationswhichcomposeFEMA(see Figure 1). UnlessFEMAcanmakesomeinternalimprovementsin thewaymitigationeffortsarestructured,itisuncertainhoweffectiveourrenewedawarenessandunderstand ingofmitigation will be. References ColoradoWaterConservationBoard1985FloodHazardMitigationPlanfor Colorado. FederalEmergencyManagementAgency(FEMA)1986A Unified NationalProgramfor FloodplainManagement.Gruntfest,E.C.1985ManitouSpringsFloodHazardMitigation Plan. Colorado Springs: University of Colorado, Center forCommunityDevelopmentandDesign.HoytandLangbein1955Floods. Princeton,NJ:Princeton University Press. National Science Foundation1980A ReportonFloodHazardMitigation. Washington,DC.NationalWaterandSoil Conservation Authority1986StemmingtheFlowof ourFloodProblems. New Zealand.RalphM.Field Associates, Inc.1985MakingMitigation Work, A PracticalHandbookforStateOfficials.Washington,DC:FEMA.SoilandWater1986"Flood Hazards inNewZealand." Soiland Water 22 (II). U.S.WaterResources Council1981FloodplainManagementHandbook.Washington,DC.Webster'sNewCollegiate Dictionary1974WrightWaterEngineersetal.1981FloodHazardMitigation. Handbook of(DIlDO 11Pracedllres far the Interagency RegionalHazardMitigation leaDS.Wasili ngtol'l oc:

PAGE 67

Figure 1 t-'I-:MANATIONALOHGANIZ"'1'IONAI.CIIAlTr---tTcdirling& i ficeArlministcdtion Prog.Ii!!!I'!-.-PiLectorll..----l-lEmcc'1p.ncOperations DirectorateI In.;urance Administration Risk. A.sscssment--I t--lQiiOiceof Insurance ..fu!.2port-s-e-rv-ice"s ] r't-:MARt-:G tONAL ORGAN 1ZAT[QNAL CHARTResourceManaGementandAdministr
PAGE 68

CHANGESATTHESTATELEVELSINCE1976RuthM.WrightHouseof Representatives,Stateof Colorado Introduction I wish I couldtellyouthatColoradohasmadegreatstridessince theBigThompsonflood in1976.Therehavebeensomegains, but therehavealsobeensomelosses,andsomelostopportunities.Inspeaking of the"statelevel"weneedtodifferentiatebetweenthe ExecutiveBranchandthe Legislative Branch.Asamemberoi the Legislative Branch, I believe Icanspeak frankly ofsomeofitsshortcom ings.Asa whole, the ExecutiveBranchgets higher gradesonthisissue than the Legislative Branch. Division of DisasterEmergencySprvices Originally a Division of Civil Defenseinthe Department of MilitaryAffairs,the Division of DisasterEmergencyServices(DODES)wascreatedbythelegislaturein1973with additionalresponsibilities,butnoadditional resources(money).Itdid notevenhaveitsowndivision head.WhentheBigThompsonfloodhitonMay31,1976,DODESwaswoefully inadequate to respond.ItwasGovernorLamm,infact,whoprovided the leadershipandthe recoveryeffortwasmanageddirectlyoutofhisoffice.Thereafter, the governor appointed aManagementEfficiencyCommitteewithexpertiseinemergencypreparednessandalso staged asurprisesimulated flood exercisetoteststateagencies,particularlyDODES.Thetestclearlyshowedup the inadequacies of thestate'semergencyresponsecapabilities.Thegovernor, together with thelegislature,workedtogether to solvethisproblem.DODESwasgivencleardirectionthatitsprimepurposewasemergencypreparednessforthestate.Thedivisionthen gotitsownexperienceddirector,Pat Byrne.Itnowhas26 full-tim!: andthree temporary employees.Ithassomestate-of-the-artCOl1lllJlln1cation syste,lIs, providesexpertiseandtrainingto support local governments in their emergency responseactivitiespriortoanevent, respondswhen em,ergencies occur, condllcts the recovery programs,andcoordinates with the federal agenciestoget ofthe recoveryassistancewhichmaybeavailable.

PAGE 69

58STATELEVELClearly, real progresshasbeenmadesince1976indisasterpreparednessandresponse.Onthe negative side,however,statefunding forDODEShasbeentenuous.InColorado, fundingistotallyinthehandsof thelegislature.ForDODESthereisheavyrelianceonfederal funds.Ofthe $1.5 millionannualbudget, only $300,000comesfromstatefunds.Whilea DisasterEmergencyFundwasalso established in the1973act,ithasneverbeenfunded.Sowhenadisasteroccurs, thereisa scramble for funds. (Prior to1980,thestatedid notevenhavea policy to allow thestatetomatchfunds forrepairofdamageto the public propertyoflocal governments.)Ifthelegislatureisin sessionandhassurplusdollars,a supplemental appropriationcanbemade.Perhaps there aresomefundsleftoverfromother agenciesattheendof thefiscalyearandthe governorcantransferthese fordisasterrecovery.Thelegislatureformerly appropriated $200,000 to a Governor'sEmergencyFundwhichthe governor couldusefor anythingfromgrasshopper control to naturaldisasterrelief.Thishasalsobeencut to $100,000.Justafewstatisticsto put theneedin perspective.Inthe past five years the experiencehasbeenthatof the100emergencycallsper year, about one-fourth requeststateassistance to local governments, ofwhichabout adozenactivatethestateemergencycenter.Six of these are seriousenoughtobedeclared a"disasteremergency"bythe governor.Everyother year there willbea request for a federaldeclaration.Ofallof the emergencies, three-fourths are waterrelated(includingtwodambreakseachyear)andone-fourth of thestate's63counties willbeinvolved in adisastereach year. ColoradoWaterConservationBoardAnotherkeyagencyinthisarenaisthe ColoradoWaterConservationBoard(CWCB).TheCWCBischarged withmakingtheofficialdelineation ofallofthe floodplains in Colorado, to provide expertise to local governmentsonflood controlprojects,andto help communitiesparticipatein the national flood insurance pro gram--thatis,to focusonthe preventive aspects of floodcontrol.Herethelegislaturehasbecomeexceedingly niggardlyandshort-sighted.From1973to1980,$150,000wasbudgeted annually to theFloodHazardDelineationFund,matchedbyanother $150,000fromlocal governments.Realprogresswasbeingmadeindelineating thestate'sfloodplains.Thenin1981thiswascut to $100,000andreduced to

PAGE 70

Wright59zero in1982,whereithasbeenever since.Twoof the sixstaffmembersof theCWCB'stechnical expertswerefirstrequired tobecash-funded(thatis,theCVCBhadto charge local governments fortheirservices)andthen cutaltogether.Onepersonhassincebeenreinstatedbecause of thedireneedtoprovidesomestatecompetencysothatnonparticipating communitiescanenterthe federal program. Also, thereisstillreview of projectfeasibilityfor small communitiesonfloodanddrainageprojectswhenthese arefundedbyother agencies suchastheCorpsof Engineers, the Soil Conservation Service,FEMA,communityblockgrants,or energy impactdollars.So,inthis-vitalarea of flooddamageprevention, thelegislatureisgivingminimalsupport.UrbanDrainageandFloodControlDistrictTheUrbanDrainageandFloodControlDistrict(UD&FCD)isoneof the successstories.Createdbystatestatuteseven years before theBigThompsonflood,thisspecialdistrictoperatesinthe six-countyDenvermetropolitan area for master planning in theSouthPlattedrainage basin.Itisauthorizedtoimposea mill levytofinanceitsoperationsandhasdonea masterful job in reducing flood lossesinthe metro area.Inauthorizinganadditional four-tenths of a mill (in addition to the basicfive-tenthsof a mill already authorized) for maintenanceandpreservationoffloodwaysandfloodplains in1979,thelegislaturespecificallyrecognized theBigThompsonflood experiencewhichillustrated"theneedfor Colorado's floodplains tobecontinually keptclearof debrisanddebriscollectingstructures."DamSafetyDamfailuresare another cause of flooddisasters,the worst in Colorado being theLawnLakeDamfailurewhichkilledseveral peopleandwreakedhavoconthe City of Estes Park. There are over 2,000damsinColorado over tenfeetin height,whichputsthemunder thejurisdictionof theStateEngineers Office(SEO).TheSEOischarged withdamsafetyinspectionsandisauthorizedtorequiredamownersto lower the water level intheirreservoirs to preventdamfailure.Bystatestatuteneitherthestate,norstateemployees, nor contract inspectorscanbeheldliablefordamfailure.Theultimateresponsibilityfordamsafety orfailurelieswith the owner. Untilrecently,ownersofdamswerestrictlyliablefordamagescausedbydamfailure,a concept adoptedfromthe Englishcommonlawonthe theorythata

PAGE 71

60STATELEVELdam,likeexplosives,wasinherently hazardous,andifitfailed,negligenceneednotbeproved. After theLawnLakedisaster,thelegislaturerevieweddamsafetyandliability.Itssolutionwasnot to ensuregreaterdamsafety but to lower theliabilityfordamowners!Itpassed astatutewhichrequired proof of negligenceifthe propertydamaged(orliveslost)werein the 100-year floodplainofthe watercourse, therebymovingawayfromstrictliability.Mostof thedamsin Colorado areagriculturalreservoirs,ownedbyassociationswhoseonlyassetsare thedamandreservoirsite,not the water or landirrigatedbythe water. Thisresultsin thedamowneroften being judgment-proof,thatis,withoutassetstopayforanydamagescausedbythefailure.Toalleviatethissituation,astatutewaspassed in1981whichstatedthatthe boardofdirectorsofsuchanownerassociation could notbeheldliableifthe association bought aminimumof$1million in insurance.Withthe recentcrisisin insuranceavailabilityandaffordability,the1986amendmentstothatstatutereduced theminimumto $500,000.Thelegislature'sresponse todamsafety,then,istomakeitmoredifficulttosuedamownersbyrequiring proof of negligence,andbyreducing theamountto $500,000thatcanprobablyberecovered forallof thedamagesorlossoflifecausedbythefailure.State GeologicSurveyTheStateGeologist's Officeisanotherkeyagencyinhazardcontrol.In1983thelegislaturecut thestafffrom16to three (the State Geologist, his deputyanda secretary)inanunwarranted punitive move--at thesametimethattheresponsibilitiesofthatofficewerebeing increased in the hazardous waste area.Atthe eleventhhoursomeofusmanagedto get abillpassedwhich at leastpermitted theStateGeologist to chargedirectlyfor his services--another cash funding"solution."Thismeantthatlocalgovernmentnowwouldhavetopayforsuchservices a review of subdivisionplatsforvulnerabilityto natural hazards. Basic geological surveyworkforwhichtherewasnodirectclienttopaythebillcould simplynolongerbeaccomplished.

PAGE 72

Wright Governor's Executive Orders61Thegovernor took hisroleinprevention of flood hazards veryseriouslyandusedallofthe executivepowersavailable tohim.Heissued Executive OrdersonAugust1,1977andOctober 1,1977;directedallstateagenciestoevaluate flood hazardswhenplanningstatefacilitiesandpreclude the uneconomic, hazardous or unnecessary use of floodplains; directedstateboardsandagencies to proceed withidentificationof floodplains,andprepare flooddisasterpreparedness plans;andtookmanyother preventivesteps.Theyalsowereoriented towardsmakingitpossibleforColorado communities toparticipateinthe federal flood insurance program.Insummary,changesatthestatelevelhavebeenmixed.TheExecutiveBranchhasdoneanoutstanding job within the budgetconstraintsimposedbythe Legislative Branch.Thelegislatureinmostareashasbeenpenny-wiseandpound-foolish,resultingin aminimalstaterolein preventive measuresandtenuous funding fordisasterrelief.References Executive Order,Stateof Colorado1977a"EvaluationofFloodHazardin LocatingStateBuildings,Roads,andOtherFacilities,andinReviewingandApprovingSewageandWaterFacilities,andSubdivisions,"August1.1977b"RequirementsandCriteriaForStateParticipationin the FloodInsurance Program," October 1.

PAGE 73

RICHARDO. LA....Gl'WflmfH EXECUTIVE CHAMBERSDENVER Aug.1,1977EXECUTIVEORDEREVALUATIONOFFLOOD HAZARD INLOCATINGSTATEBUILDINGS,ROADS,ANDOTHERFACILITIES,ANDINREVIEWINGANDAPPROVINGSEWAGE AND WATERFACILITIES,ANDSUBDIVISIONSWHEREAS,hazardoususesofColoradofloodplainsareoccurringandpotentialfloodlossesandlossoflifeare increasidS despitesubstantialeffortstocontrolfloods;and WHEREAS, economiclossesduetofloodsinColoradoduringthelasttwelveyearsplaceColoradonearthetopoftheNation'Blistforpercapitaloases;andWHEREAS,pastinadequatelandusepolicyandcontrolsledtothemajordisasterintheBig Thompson Canyon onJuly31,1976; andWHEREAS,minimumfloodplainand floodwayregulationcriteriahavebeenpromulgatedbytheColoradoWaterConservationBoard andtheColoradoLand Use Commission onthepremisethatwiseuseofourState'sfloodplainsisthekeytocontrollingandminimizingfutureeconomiclossesandaufferingofourcitizens;andWHEREAS,wiseuseofourfloodplainswillpromotepublichealth,safetyandwelfare,reducefuturepubliccostsforreliefandrehabilitationandcontributetotheState'seconomy; andWHEREAS,theStateofColoradohasextensiveandcontinuingprogramsfortheconstructionofbuildings,roads,andotherfacilitiesandfurther,StateAgenciesareinvolvedinthereviewandapprovalofwaterand sewer treatmentplants,subdivisions,trailerparks,campgrounds, andmanyotherfacilitiesthroughouttheStateofColorado;andWHEREAS,bothFederalandStateAgencies havecompiledsignificantdataandstudiesconcerningthefrequencyoffloodssndthelocationoffloodplainsandareexpertatestimatingfloodhazards; NOW, THEREFORE,byvirtueoftheauthorityvestedinmeasGovernorofColorado,itisherebyordered as follows:1.Theheadsof itate agenciesshallprovideleadershipinencouraging a broadandunifiedefforttopreventuneconomicusesand developmentofColoradofloodplainsandinparticular,topromotethepublichealth,safetyandwelfareandtoreducetheriskoffloodlossesinconnection with ColoradolandsandinstalLationsandStatefinancedor8upported improvements.

PAGE 74

2.AllStateagencies directly responsiblefortheconstructionofStatebuildings, structures, roads,overnightcampgrounds,orotherfacilitiesshallevaluatefloodhazardswhenplanningthelocationfor new facilitiesandasfaraspracticableshallprecludetheuneconomic,hazardous,orunnecessaryuaeoffloodplains in connection with suchfacilities.3.Wheneverpracticalandeconomicallyfeasible,floodproofingmeasuresahallbeappliedtoexistingfacilitiestoreduceflooddamagepotential.4.TheColoradoWaterConservationBoard andtheLand Use CommissionincooperationwiththeappropriatestateandfederalagendesshallcontinuetoundertaketheevaluationofhazardousfloodplainusesintheStateofColorado,proceedwiththeidentificationoffloodolains.andoreoaresuitableflooddisasterpreparednessplansincooperationwithaffectedcities dnd counties,includinganeffectivefloodinsuranceinformationprogram, early warningsystem,andrelatedstepstoprotectagainstfuturelossoflifeandunnecesaaryeconomiclosses.PriorityshallbegiventothenumeroushazardouscsnyonsintheStateofColorado.5.AllStateagenciesresponsibleforthereviewand/orapprovalof sewage treatmentplants,vatertreatmentplants,interceptorsewers,subdivisions,trailerparks,andotherfacilities within theStateofColoradoshallevaluatefloodhazardsin writing inconnectionwithsuchreviewandapprovaloffaciltiesandtakemeasurestominimizetheexposureof facilities, and development whichtheymayinduce,topotentialflooddamage andtheneedforfutureStateexpendituresforfloodprotectionandflooddisasterrelief.6.AllStateagenciesresponsibleforprograms whichentaillanduseplanningshalltakefloodhazardsintoaccountwhenevaluatingapplicationsforplanninggrants,whenreviewingwaterandwastewaterfacilityplans,andarea-widewastewatermanagementplans.7.Requeatsforfloodhazardinformationandhazard asseSBment msybeaddressedtotheColoradoWaterConservationBoardortheLand Use Commission.8.AnyrequestsforappropriationsforStateconstructionof new buildings,structures,roads,orotherfacilitiesbyStateagenciesshallbe accompaniedbyastatementonthefindingsoftheagency'aevaluationandconsiderationoffloodhazardsindevelopmentofsuchrequests.9.AsusedinthiaOrder,theterm"Stateagency"includesanydepartment,commission,division;orotherorganizationalentityoftheexecutivebranchofStateGovernment.10.TheState aRencies shallproceedimmediatelytodevelopsuchprocedures,regulations,andinformationasareprovidedfor in, ormaybenecessarytocarryout,theprovisionsofthisExecutiveOrder.GIVENundermyhand andtheExecutiveSealoftheStateofColorado,thisfirstdayAugust,A.D.,1977. Ridf!1rd D.Lamm Gov,rnor

PAGE 75

O. LA.MMGovernor EXECUTIVE CHAMBERS EXECUTIVE0RDER REQUIRH1EiHS ANDCRITERIAFORSTATEPARTICIPATIONINTHENATIONALFLOOD PROSRAM OeLl,1977WHEREAS,onAugust1,1977, Executive OrderNumber8491,entitled"EvaluationofFloodHazardin Locating State Buildings,Roads,andOther Facjj ities,andinReviewingandApprovingSewageandWaterFacilities,andSubdivisions,"wasissued regardingStatepolicyonthe occupationandmodificationofColorado floodplainsbyState agencies;andWHEREAS,additional State procedures are tobeestablished tomeetthe requirementsofthe NationalFloodInsuranceProgram;andWHEREAS,theavailabilityofprograJ'lsfor Federal loansandmortgageinsurance,Statefinancialassistance,andlanduseplanning are determiningfactorsin theutilizationoflands;andWHEREAS,theavailabilityofflood insurance under the NationalFloodInsuranceProgramfor state-owned properties as providedbythe NationalFloodInsuranceActof 1968, asamended,andtheFloodDisaster ProtectionActof1973isdependentuponState coordination of Federal,State,andlocal aspectsoffloodplain,muds1ide(i.e.,mudlfow)area,andflood-related erosion area manageJ'lent activitiesin theState;andWHEREAS,the ColoradoWaterConservationBoardisthe Stateagencyresponsible for state-wideprogramsfor flood prevention, floodcontrol,floodprotection,andflood hazard studycriteria,as providedbySection 37-60-106(1), Colorado StQtutes 1973,and 1-403, Colorado Revised Statutes 1973,asamended,(S.B.126)L.77.;andWHEREAS,the ColoradoWaterConservationBoardisthe Stateagencydesignatedtocoordinate the NationalFloodInsuranceActof1968,asamended,andtheFloodDisaster ProtectionActof1973;andWHEREAS,the DivisionofDisasterEmergencyServicesistheagencyresponsible for the c0ordination ofFederal,State,andlocaldisasteractivities,andWHEREAS,the primary concerns of the ColoradoLandUseCommissionare theprotection,utility,value,andfutureoflands within theState;and

PAGE 76

WHEREAS,theavailabilityof flood insuranceforstateowned propertiesisconditionedupontheState'scompliance withminimumfloodplainmanagementcriteriaofthe NationalFloodInsuranceProgramregulations(24CFR1909,et.seg.);NOW,THEREFORE,byvirtueof theauthorityvested inmeas theGovernorof Colorado.itishereby ordered as follows: 1.TheColoradoLandUseCommissionishereby designated as theStateagency to provide implementation of Section 1910.12, RulesandRegulationsofthe Federal Insurance Administration. 2.EachStateagencyhasaresponsibilityto evaluate the potentialeffectsofanyactionsitmaytake in a floodplain, to ensurethatitsplanning programsandbudget requestsreflectconsideration of flood hazardsandfloodplain management. 3. Before takingaction,eachState agency shall theproposed action will occur in a floodplain. This determinationshallbebasedona Department ofHousingandUrbanDevelopmentflood hazard boundarymap(FHBM)or,ifavailable,onmoredetailedfloodplaindelineationmapsof the areaonfilewith the ColoradoWaterConservationBoard.Ifflood hazard informationanddata are notavailable,the ColoradoWaterConservationBoardshallassistin the determinationandthe evaluation ofanyflood hazard to the proposedfacilitiesorstructures.4. For state-owned properties in Federal Insurance Administration designated "SpecialHazardAreas," theStateshall,asaminimum,complywith the floodplainmanagementcriteriasetforth in Sections 1910.3, 1910.4,and1910.5ofthe NationalFloodInsurance Regulations.5.IfaStateagencyhasdeterminedthatnofeasiblealternativeexiststoavoidsitinga proposedstructureorfacilitywithin afloodplain,the agencyshall(a) prepareandtransmit to the ColoradoLandUseCommissiona notice containinganexplanationof wh the developmentisproposed tobelocated in the floodplain; (b) require thestructuretobedesigned (or modified)andade quately anchored to preventflotation,collapse,orlateralmovement; (c) require thestructuretobeconstructed with materialsandutilityequipmentresistanttoflooddamage;(d)sitethe lowestfloorofanystructurenotlessthanonefootabovethe base flood, unless suchstructurehasbeenadequately flood-proofed to one footabovesaid base waterelevation;and(e) elevateresidentialdwellings to notlessthanonefootabovethemaximumwater elevation of thecomputedbase flood. 6.TheColoradoLandUseCommissionandthe ColoradoWaterConser vationBoardshallassistStateagencies in carrying out the floodplainmanagementcriteriasetforthin Sections 1910.3, 1910.4,and1910.5ofthe NationalFloodInsurance Regulations with the follow ing provisions:

PAGE 77

a. Subdivision proposalsshallbeconsistentwith thecriteriaestablishedbyTitle3D,Article28, Colorado RevisedStatutes1973, asamended.b.Policyonfloodplainmanagementshallfollow thedirectivesofExecutive Order8491ofAugust1,1977.c. Disaster PreparednessActivitiesshallbeconsistentwith thecriteriaestabl byTitle28,Article2, Colorado DisasterEmergencyAct, Colorado RevisedStatutes1973, asamended,within the scope oftheirapplicabilitytothe Executive OrderandtoExecutive Order 8491, datedAugust1,1977,andasadministeredbythe Colorado DivisionofDisasterEmergencyServices. Providedfurther,noting inthisorderonin Executive Order8491shallapplytoassistanceprovided foremergencyworkto savelives,protectproperty,andpublic healthandsafety, perforffiEd pursuanttothe Colorado DisasterEmergencyAct.d.Thefloodway (high-hazard zone)limitsshallbeconsistentwith thecriteriaestabiisnedbythe ColoradoWaterConservation Board'sModelFloudplain Regulation, dated February 26, 1975,whichwasprepared under theauthorityofTitle24,Article65.1, Colorado RevisedStatutes1973, asamended.7.AllStateagencies responsibleforthe disposal of lands orpropertiesshallevaluate flood hazards in connection with lands or propertisswhich are proposed for disposal to other publicinstrumentalitiesorprivateinterestsand, in order to minimizefutureStateexpendituresforflood protectionandflooddisasterrelief,shallattachappropriaterestrictionswith respect to usesofthe lands orpropertiesfromdisposal. b.i"llo:i pl-operty in ispl'opused forlease,easement, right-of-way, or disposal to non-state public orprivateparties,the State agencyshall(a) reference in the conveyance those usesthatarerestrictedunderidentifiedFederal, State or local floodplainregulations;and(b)attachotherappropriaterestrictionstothe uses ofpropertiesbythe grantee or purchaserandanysuccessors, exceptwhereprohibitedbylaw; or (c) withholdsuch pro;Jt=r:ies fromconveyance. 9.Asused inthisOrder: a. "State agency"meansanydepartment, board, commission, ordivision;however, thedirectivesascontained inthisOrder aremeantto apply to those agencieswhichperform or regulateactivitiesthatare locatedin,oraffect,floodplains.

PAGE 78

b."baseflood"meansthefloodthathasaonepercent chanceofbeing equalled or exceeded inanygiven year. c. "floodplain"meansanareain,andadjacentto,a stream,whichareaissubjecttobeing inundatedbythe base flood inanygiven year. d. "Flood-proofing"meansa combinatiDnDfstructuralprovisiDns, changes, or adjustmentstolands, prDperties,andstructuressubjecttDf1DDding,primarily for the reductiDn or e1iminatiDnDff1DDddamagestDlands,properties,structures,andcDntentsDfbuildings in a f10Dd-hazard area. 10.Asmaybepermittedbylaw, theheadDfeach State agency shallissue apprDpriate rulesandregulationstDgDvernthe carrying outDfthe prDvisiDnsDfthisorder in cDnsu1tatiDn with theCD10radDLandUseCDmmission.11. This OrdershalltakeeffectDnOctDber1,1977.GIVENundermyhandandthe Executive SealoftheStateofCo1DradD,this1stdayofOctDber, A.D.,1977.RichardD.LammGDvernDr

PAGE 79

SUCCESSFULFLOODMANAGEMENTONAREGIONALBASISWilliamG.DeGrootandL.Scott TuckerUrbanDrainageandFloodControlDistrict,Denver,COIntroductionTheUrbanDrainageandFloodControlDistrictwasestablishedbythe ColoradoLegislaturein1969toassistlocal governments in theDenverMetropolitan area withmulti-jurisdictionaldrainageandflood control problems.Startingwith astaffoftwoanda budget of approximately$400,000 the Districthasgrown,in acarefullyplannedandwelljustifiedmanner, to astaffoffifteenwithanannual budget of approximately$8,000,000.Thehistoryofthatgrowthanda discussion of thekeypolicy decisionswhichfacilitatedthat gl'owth are given below.Boardof DirectorsTheDistrictisanindependent agency withitsownBoardofDirectors.Ifthereisasinglekeytothe success of theDistrict,itistheBoardofDirectors.Themake-upof thefifteenmemberBoardisunique, inthatitiscomposedmainly oflocallyelectedofficialswhoare appointed to the Board.Membershipincludes theMayor,orDeputyMayor,of Denver; threeDenverCity Councilmembers;onecommissionerfromeach ofAdams,Arapahoe, Boulder, Douglas,andJefferson Counties;andonemayorfromeach ofAdams,Arapahoe, Boulder,andJefferson Counties. Thesethirteenlocallyelectedofficialsselecttworegisteredprofessional engineerstocomplete theBoardmembership.AreaTheDistrictincludes the CityandCountyofDenverandthe urban or urbanizing portions of thefivesurrounding counties. There are presently35citiesandcounties within theDistrict.TheDistrictcoversanarea of approximately1,200square miles. There are approximately1,200miles of major drainageways havingtributaryareas ofatleast1,000acres.Thepresent population of theDistrictisapproximately1.8million people.FundingTheDistrict'sprimary source of fundsisa propertytax.TheDistrictiscurrentlyauthorized to levyuptoonemill.Although FederalandStatefundshave

PAGE 80

DeGrootandTucker69beengranted to theDistrictin thepast,theDistrictdoesnot relyonanyothersource of fundingatthistime. ResponsibleGrowthThe1969legislationwhichestablishedtheUrbanDrainageandFloodControlDistrictgaveitfairlybroadpowersbut verylittlemoneyto implement those powers.Initially,theDistrictwasauthorized to levy 0.1 millforplanningandoperations,whichamountedto approximately $400,000.Thefirstmajoractivityof theDistrictwasto inventory drainage basinsandsub-basins to determine the extent of problemsandto develop a plan toattackthose problems.Theinitialstudy indicatedthatapproximately25%of the major drainageway miles within theDistrictweredeveloped, with the remaining75%undevelopedandamenable to preventive approaches.Itwaslogicalthat,ifeffectivepreventive measures couldbeundertakenonthe undeveloped drainageways,significantsavings infutureremedial needs couldberealized.TheDistrictBoardthereforemadeacommitmenttopreventiveactivitiesanddeveloped a comprehensive floodplainmanagementprogramto preventnewproblemsfrombeing created.TheDistrictalsorealizedthatthe SouthPlatteRiver, thebackboneof the drainage systemfortheentireDenvermetropolitanarea,wassolargeandhadsomanyproblemsthatitcould absorballof theDistrict'stime,effort,andmoney.Therefore theBoarddecided to emphasizeworkonthetributariesto the SouthPlatteRiver.In1973theDistrictrequestedauthorityto levyanadditional 0.4 millfora designandconstruction program,andthelegislaturegrantedthatrequest, beginning in1974.Also in1974,theBoardestablisheda floodplainmanagementprogram.In1979, theBoardrequested a 0.4 mill increaseformaintenanceandpreservation of floodplainsandfloodwaysfromthelegislature.Thelegislationpassed, althoughitwaslimited to taxable years1980to1983.In1983the timeframewasextendedindefinitely.So,by1980, theDistricthadbeenauthorized to levyupto0.9 millforthe following purposes: planningandoperations (0.1mill),designandconstruction (0.4mill)andmaintenanceandpreservation (0.4mill).Withseveral years of experience,andmanymaster plansandconstructionandmaintenance projects completed or underway, theDistricthastackled the SouthPlatteRiver(SPR).A master planning studyfortheSPRwascompleted inlate1985.Usingthe master planasthe basisforitsrequest, theDistrictsoughtanadditional 0.1 mill authorization with funds tobeearmarkedfortheSPR,andthe

PAGE 81

70REGIONALMANAGEMENT1986legislatureapprovedthatrequest.TheDistrictnowhasa comprehensiveprogramaddressingallaspects of floodmanagement,asetoftriedandprovenpoliciesandprocedures,anda reasonableandreliablelevel of funding. Details of the individualDistrictprograms are provided ingreaterdetailbelow. Master PlanningProgramThemaster planningprogramisfunded out of theoriginal0.1 mill authorizationfortheDistrict.Keypolicy decisionswhichguide the program implementation areasfollows: (1)Eachmaster planningeffortmustberequestedbythe local governmentsandmustbemulti-jurisdictional;(2) Master plansarecompletedbyconsultants acceptable toallaffectedlocal governmentsandtheDistrict;(3)TheDistrictwill provide necessarymappingandwillpay50%of the consultingcosts,with the local governments sharing theother50%of the consultingcosts;and(4)Themaster planmustbeacceptabletoalltheaffectedlocal governments. Aftermanyyears of concentrating almostsolelyonmajor drainageway master planning, theprogramhasnowevolvedintofour major areas ofinterest:(1)Majordrainageway master planning; (2) Outfall systems planning; (3) Drainagecriteriamanualsforlocal governments;and(4) Specialprojects,suchascriteriaforchannelsandstructuresonsandysoils,benefit-costanalysis,andwetlandissues.Master planshaveprovidedanimportant tooluponwhichtoidentifyprojectsforconstruction.Themaster plans provide valuable input to theDistrict'sFiveYearCapitalImprovementProgram.Theyhavealsobeenusedonnumerousoccasions to preventprojectswhichwouldhaveinvalidated the masterplans ormadethemmuchmoreexpensive to implement;andtoidentifyandacquire right-of-way neededforfuture improvements.Theprogramstaffconsistsofoneregisteredprofessional engineer(PE)andonestudentintern.There are46major drainagewayand15outfallsystems master plans completed or in progress. DesignandConstructionProgramPriorto theinitiationof the designandconstructionprogramin 1974, theBoardadoptedpoliciesforthe use of those funds.TheBoardestablishedpolicies

PAGE 82

DeGrootandTucker71thatwoulddistributethe funds insuchawaythatlocal governmentswouldnotbeconcernedthatoneportion of theDistrictwouldbesubsidizing construction in another portion.Thekeypolicy decisionswereas follows: (1) Proposed improvementsmustberequestedbylocal governments; (2) Proposedimprovementsmusthavebeenmaster planned; (3)Districtfundsmustbematchedbylocal governments; (4)Localgovernmentsmustagree toowncompletedfacilitiesandmustaccept primaryresponsibilityfortheirmaintenance; (5)Districttax revenue receivedfromeach county willbespentforimprovementsbenefittingthatcounty over a periodfrom1974tofive years into thefuture;and(6)TheDistrictwill not develop a publicworksdepartment but willrelyonexistinglocal governments' publicworksdepartments.TheDistrict'sapproach to designandconstructionisintended to minimize theneedfora largestaff.Generally theDistrictcoordinates final designs preparedbyconsulting engineers.Thelocalentitiesare involved inallaspects of the design process.Thelocalentitiesgenerally acquire the necessary rights-of-way(ROW)andserveasthe construction contracting agency.TheDistrictis,however, sometimes the lead agencyforROWacquisitionandconstructioncontracting.Allcostsassociated with design, right-of-wayacquisition,andconstruction are sharedona 50/50 basisbetweentheDistrictandthe local governments.Eachyear theBoardadopts a FiveYearCapitalImprovementProgramwhichlistsprojectsandDistrictparticipationbycountyfrom1974to five years into thefuture.This plan thenformsthe basisforDistrictparticipationin the designandconstruction program.TheprogramstaffconsistsoftwoPE'sandonestudentintern.Theprogramhasbeeninvolved in$71million of constructionprojects,including$31million inDistrictfunds. FloodplainManagementProgramTheFloodplainManagementProgramwascreated in1974toestablisha preventiveprogramtokeepnewproblemsfrombeing createdandto consolidate severalactivitieswhichhadreceivedrandomattentiononanavailabletimebasis.Themajoractivitiesincluded in theprogramare: (1)TheNationalFloodInsurance Program, (2) Floodplainregulation,(3)Floodhazard areadelineation,(4)Flood

PAGE 83

72REGIONAL warning, (5)Flooddamagesurveys, (6)Reviewsof proposed developments in or nearfloodplains,and(7) Public information.TheDistrict'sBoardof Directorshasauthoritytoregulatefloodplains buthaschosen not todosoaslongasthe local governments are implementingtheirownfloodplainregulations.Atthesametime, theDistricthasassistedmanylocal governments withtheirfloodplainregulations,includingassistancewith requirements of the NationalFloodInsurance Program.TheDistricthasworkedwith the FederalEmergencyManagementAgency(FEMA)not only toassistthe local governments, but also to attempt to ensure compatibilitybetweenfloodplains definedbytheDistrictandfloodplains defined in flood insurancestudies.Anearlyandcontinuingconflicthasbeenthe use of hydrology basedonprojectedfuturedevelopment of the drainage basins (theDistrictapproach) versusFEMA'sinsistenceonusingexistingdevelopment to define the hydrology. Thisconflictcontinues.TheDistrictcontinues toidentifyandpublish, throughitsflood hazard areadelineationprogram, 100-year floodplains in undeveloped or sparsely developed areassothata defined floodplain willbeavailableforfloodplain regulationwhendevelopment reaches thoseareas.TheDistricthasbeenactiveinassistinglocal governments in the developmentofflood warning plans using bothspotterandinstrumented detectionalternatives.Inaddition,theDistrictretainsaprivatemeteorological service to provideforecastsofpotentialflood producing eventstoallthe local governments within theDistrict,aswellasto provide support services inspecificflashflood warning plansestablishedforindividual drainageways.In1976theBoardof Directors decided tomakea specialefforttonotifyoccupants of floodplains of the floodpotentialthey face.Theresultwasaprograminwhichaninformational brochureismailed toeachaddress located in or adjacent to eachidentified100-yearfloodplain.In198622,000 brochuresweremailed underthisprogram.In1980,afterapproval of the maintenance mill levy, theBoardestablisheda policywhichstatedthatallprojectsconstructed by, or approvedforconstruction by, local governmentsafterMarch1,1980wouldhavetomeetthe following conditions in ordertobeeligibleforDistrictmaintenanceassistance:(1)Theprojectswouldhavetobedesigned in accordance with theUrbanStormDrainageCriteriaManual,(2)TheplansandspecificationsmustbeapprovedbytheDistrict,(3)Theprojectmustbebuiltin accordance with the approved plans,and(4)

PAGE 84

DeGrootandTucker73Maintenance access, both legalandphysical,mustbeprovided.Theserequirementshavebeena veryeffectivetool in upgrading thequalityof flood controlfacilitiesbuiltbydevelopers.Thekeypolicy decisionsforthe FloodplainManagementPrograminclude: (1) Active support of the NationalFloodInsurance Program, (2) A decision not to implement theDistrictfloodplain regulationwhenlocal governments are doinganadequate job withtheirown,(3)Annualnotificationof floodplain occupants of the flood hazardpotential,(4) RequiringDistrictapproval offacilitiesbuiltbyothers before they willbeconsideredeligibleforDistrictmaintenanceassistance.TheprogramstaffconsistsoftwoPE's.Over700miles of 100-year floodplainshavebeendefinedbythe FloodplainManagementandMaster Planning Programs. MaintenanceProgramKeypolicy decisionsforthe MaintenancePrograminclude the following: (1) Maintenance offacilitiesfundedbytheDistrictshallbethe primaryresponsibilityof the local governments; (2)Tothe extent the funds areavailable,theDistrictwillassistlocal governments with maintenanceandpreservation of floodplainsandfloodways; (3)Theorder ofpriorityfor expenditure ofDistrictmaintenance fundsisDistrictownedprojects,Districtfundedprojects,projectsfundedbyothers,unimprovedurban drainageways,andunimprovedrural drainageways; (4)Fundsderivedfromthe maintenance mill levy are returned toeachcounty in thesameproportionasthey are receivedonanannualbasis;(5)Localgovernments are not requiredtomatchDistrictmaintenance funds;and(6)Thepolicy of notcreatinga publicworksdepartmentwasreaffirmed.Theprogramstaffconsistsof three PE's,twofieldmaintenance supervisors,andtwostudentinterns.Theannual budgetisapproximately $3.6million.Allmaintenanceactivities,includinganydesignworkrequired, aredonebyprivatecontractors.SouthPlatteRiverProgramAsnotedearlier,a River beginning in1987.develop a program.Some0.1 mill levyhasbeen authorizedforthe SouthPlatteAsthisiswritten,preliminary steps are being takentoissueswhichmustbefaced include: (1)Theamountof

PAGE 85

74REGIONALMANAGEMENTmoneytobeusedforcapitalconstruction,(2)Theamounttobeusedformaintenance, (3)Theneedforlocal matching requirements,and(4)Theneedforanallocationformula to the various reaches of theriver.Asetofpolicieswillbeadoptedlaterin1986.TheUrbanDrainageandFloodControlDistricthasestablisheda successful regional approach to floodmanagement.Theapproachisbaseduponthe philosophyofcorrectingproblems created in thepast,while preventingnewproblemsfrombeingcreated.NOTE:This paperwasinitiallypresentedatthe TenthAnnualConference of the Association ofStateFloodplain Managers, June 15-20,1986.

PAGE 86

HOWTHEBIGTHOMPSONFLOOOHASAFFECTEDLOCALFLOODPREVENTIONEFFORTSbySpenser W. Havlick College of EnvironmentalDesignUniversity of Colorado-BoulderandBoulder CityCouncilmemberOnthistenth anniversary of theBigThompsonflood there are atleastthreeratherdistinctposturesthatpublicofficialsseemto takeinregards to the appropriate preventioneffortsneededto avoid another calamityliketheBigThompsonevent.Oneposition couldbecharacterizedasavoidance ofaction. We could not afford toprotectourselves adequately againstthisunlikely eventrecurring.Thesecondwouldbegeneralneutrality,laissez-faire,and"wewill abidebyfederal guidelines"attitude.Overtimewewilldowhatis convenient totryto prevent floodway encroachment.Thethirdlocalattitudeshowsa strongcommitmentto evacuate the100year floodway over time, preventnewconstructionthereandgenerally takeanaggressive stance to prevent areenactment of anotherBigThompsonevenifitchanges zoninganddevelopmentpatternsfromresidentialorcommercial toagricultural,openspacerecreationaluseor to ahighhazard overlay zone. Thereisa stong temptation tousethepoliciesof Boulder, Colorado beforeandaftertheBigThompsonCanyondisasterasa case study. This presentationsuccumbstothattemptation but onlyaftermention ismadethatrecent researchhasshownthatinfact,a major eventliketheBigThompsonhashadspecificpolicyandplanning impacts not only along the FrontRangeofColorado(atthe local level) but also impactshaverippled out to several othercitiessituatedinclose proximity topotentialcanyondischarges of perilous consequences.Ina 1984-85 study of bothprivateandpublicsectorresponse topotentialfloodandother natural hazards, thefactthatthe researchteamwasfromColoradousuallyinitiateda question about ourfamiliaritywith theBigThompsonFloodof1976or themorerecentLawnLakedambreakwhichflooded part of Estes Park,

PAGE 87

76LOCALEFFORTSColorado.Itwasofsomesurprisethatflood managers, planners,architects,engineersandother pUblicofficialsincitiessuchasAlbuquerque, Phoenix,SaltLakeCityandSeattleaskedwhatimpacts theBigThompsonhadoncurrentfloodmanagementstrategiesandwhatthepotentialwastoday for a recurrence. Generally speaking, the impact of theBigThompsononlocal flood preventioneffortsbeyondthestateof Coloradoseemedto servemoreasa naggingandratherunpleasant reminderthatdisastersofthismagnitudehappento contemporiesandthatmitigationmeansshouldbetaken to the degreethateconomicconditions warrant--especiallyifstateor federal funding isavailable.Thecentraldilemmaishowdoesa localcommunitywith a long term vision of providing flood preventionstrategiesget developerswhoare eager to capture short termprofitsto bear the upfrontandoften major costs of flooddamageprevention. Boulder, Colorado, located about25miles southoftheBigThompsonCanyoncontinues Boulder, Colorado, June,1894

PAGE 88

Havlick77tostrugglewiththissamedilemmadespite the close geographic proximity, reasonablyclearmemeoryofthe loss oflivesanddevastatingdamage,andalmostidenticalwatershed,canyonandphysiologicsettingcoupled with a denseurbanconcentration of 85,000 nestled at themouthof acanyonnotdissimilarto theBigThompson,plus eleventributarystreamsandfloodways with absolutelynoworkable warning systemavailable.Thecapture of short-termbenefitsare notalwaysintheformofdollarsnorare the developers alwaysfromtheprivatesector.Someofthebenefitsof locatingonthe100year floodway in Boulder are theso-calledintangibleswhichinclude close proximitytodowntown,governmental buildings already beingthere,andtheaestheticsof ariparianlocation.Examplesof publicsectorencroachment,newconstruction,andproposalsformultimilliondollarcityor countyownedbuildings include thecity-countyjail,municipal buildings includingcityhallandthe majorityofthecitygovernment administrativeofficesincluding parksandrecreation,planningandpublicworksplus themainlibraryandrecent proposals for aculturalcenterandlibraryexpansion. Perhaps thecentralquestionis"DidtheBigThompsonhaveanyimpactonlocal flood preventionefforts?"This observerwouldemphatically say yes but with varying degrees of enthusiasm dependingona multitude offactors.Butoverall documentationcanbepresented toshowwhatthe ordinancesinthe City of Boulderhadto say about flood plain regulations beforeandafter1976.Floodregulationsfromthe Boulder RevisedCodeof1969*weremarkedlychangedin1977and1978. Interviews withstaffin the PublicWorks,PlanningandParksandRecreation departmentsaswellaswith City CouncilmembersandCity Attorney'sofficeall revealthattheBigThompsonhashadadirectinfluenceontheminmakingthe floodplain regulationsmorestrictwith specialattentiontolifesafetyissues includingdetailedflood warning systems, evacuation simulationsandpost-disasterpreparations.However,wenowhave850newresidentialunitsand160newcommercialstructuresin the flood plan.*Ordinance3505B.R.C.

PAGE 89

78LOCALEFFORTSOverthelastfiveorsixyears therehavebeenincremental improvementsinthe basic regulationsofthe1978ordinance.Inaddition to theBigThompsoneventFEMAmapsandrevised federal guidelineswereavailable.Thefederal governmentmayhavebeenpromptedto complete flood plainmappingbythedisasterwest of Loveland, ColoradoandtheRapidCity,SouthDakotaflood of 1972.Butevenwith a very progressiveUrbanFlood ControlDistrictStaff,enlightenedcitystaffinthe publicworksandplanning departments and/or supportiveprofessionalsat thestatelevel,onewill not see local ordinances enacted to prevent floodplainencroachment or development.Totrulyaccomplish appropriate long-term flood plain zoning acitymusthaveelectedofficialswhoare willing to remaindiligent,persistantandvigilantagainst the continual stream ofapplicationsfor floodplainor floodway development.Thepressuresona councilmember,commissioner orotherelectedofficialwhoservesona locallegislativeassembly are tremendous.Eventhe appointment of aBlueRibbonTaskForceonTributariesdid not get thecityof Boulderintoanaction plan.Argumentsaremadebydevelopersthattrytoshowthatnodevelopment in a floodwayisdiscriminatory,antibusiness,uneconomicandinsensitiveto the technology available for floodproofing orearlywarning systems.Butthosewhocry antiprogress areseldompresentwhena subdivisionisunderwater several yearslater.Theresidentialor commercial property has severely reducedresalevalue immediatelyafterthe flood.Thosewhoaskedfor loweringofstandards orinsertingvariances in the flood plain regulationsdonotseemtocomeforthina postdisastertorestorethelivesandpropertythathavebeendestroyed.Armedwith aslightmajority of councilmembers(andsometimesevenonaunanimousvote) the Boulder City Councilhasoutlawednewresidentialconstructiononthe BoulderCreekfloodway sinceDecember1975.In1983and1984increased precautionswereadded, over the objection of several local developers, toraiselifesupport systems in commercial buildingsabovethe100year flood elevation along with other regulations including auditory warning devicesandspecialsignalsin building lobbies.Surprisinglythe CityofBoulder has yet toprohibitthe construction ofhotels,boarding housesandmotelsinthe floodways of Boulderdespiteaprohibitiononallotherresidentialstructures.Onemight speculatethatovernight guestsandhotelvisitorsmightbemuchmorevulnerable to loss oflife

PAGE 90

Havlick79anddeprivation notknowingtheidiosyncrasies,probabledirectionor duration of flood waters in Bouldercomparedto permanent Boulderresidents.Yetupuntilthiswriting therehasnotbeena majority of the City Council voting tobanhotelsinthe100year floodway. PerhapsiftheBigThompsonhadhadmoremotelsandhotels presentanddamagedin1976the City of Boulderwouldhavebannedfloodway hotelsbynow.Perhapsoneoftheshining achievementsinreducing level ofvulnerabilityis the flood warning system cooperatively establishedbythe CityandCountyof Boulder. A network of33monitoringstationslocated throughout the watershed regionandlinked to a central data receiving control center feed flood warning dataona twenty-four hourbasis.Annualflood warningalertsandmobilizationkeepequipmentandpersonnelinreadiness. Amobilemergencycommunicationfacilityhas

PAGE 91

80LOCALEFFORTSbeendevisedinasmuchasthe present emergency communicationfacilityisitselflocated in the BoulderCreekfloodway.Howeveraprotectivefloodproofing wall hasjustbeencompleted around the BoulderCountyJusticeCenter wherein thedisastercommunication centerislocated.Insummary,itisbelievedbythisauthorthatthe perception of magnitude ofriskandvulnerabilityhasbeentremendously heightenedinBoulderbytheBigThompsonCanyonFloodonly10yearsand25milesaway.Otherfactorswhichhavemobilized thecommunitysupportandthepoliticalinclinationtodomorethan the federal requirements include other nearby flood tragediessuchasthose in Cheyenne, Estes Park,RapidCityandBoulder'sownfloods of 1894,1916and1969.Certainly

PAGE 92

Havlick another strong elementisacity'sstaff*andmanagementwhichkeepsintouch with flood hazard researchandappropriate long-term mitigation measuresandsuppliesthatinformation to electedofficialswhohavethe courage to takeanaggressive stand in behalf of primarilynonstructural,longenduring measures of flood loss reduction.81*IndividualssuchasJimPiper, Jane Greenfield, JoedeRaismes,EdGawf,Barbara Evans, TerryWare,DaveRhodes,RogerHartmann,JerryOlsenandScottTuckertonameafew.

PAGE 93

POSTFLOODHAZARDMITIGATION:ALEGACYOFBIGTHOMPSONRutherfordH.PlattUniversity of MassachusettsatAmherstIntroductionIn1979,theU.S.WaterResources Council invitedmetoconduct a study of federal policy regarding postflood recoveryandhazardmitigation.Thestudy involvedtwocomponents: (1) a reviewofexistingfederalpoliciesandprogramsrelatingtopostdisasterrecoveryand(2) aseriesof casestudiesof recent flooddisasterrecovery experience.TheBigThompsonFloodofJuly1976figured promi nentlyamongthelatter.This paper willbrieflyreview the findings of the1979study, withparticularreferencetoBigThompsonCanyon,andwill thensummarizesomeissues facing hazard mitigation assessmentasconductedbythe FederalEmergencyManagementAgencytoday.BetweenJuly 1,1973andJune20,1979,the UnitedStatesexperienced193"majordisasters"and77"emergencies" declaredbythepresident;about80%involved floods.Majordisasterdeclarationsapplied to 2,164 counties (not corrected for counties declaredmorethan once),involved 455,343 applicants fordisasterassistance,and68,284 families relocated to temporary housing. OutlaysfromthePresidentialDisasterFundduringthisperiodamountto about $1.5billion.Total federalcostsassociated with recoveryfromfloods duringthatperiod exceeded$4billion(Platt,1979,p.1).Mitigation of future flood losses through appropriate pre-andpostdisasteractionshadbeenestablishedasa national goal in several congressionalandexecutive enactments.TheNationalFloodInsuranceActof 1968,assubsequentlyamended,required local communities to adopt floodplainmanagementmeasures tomitigatefuturelossesin order toqualifyfor flood insuranceavailablethrough the program.TheFloodDisaster ReliefActof1974(PL93-288) revised the Federal Disaster AssistanceProgramandincluded in Section406a requirementthatlocalitiesandstatesprepare long-term hazard mitigation plansasa condition to receiving federaldisasteraid.Executive Order11988,issuedbyPresident Carter in1977,similarlycharged federal agencies with reducing flood hazards throughtheiractionsandpolicies.Despite theseandother federal statements ofintent

PAGE 94

Platt83regardingpostdisastermitigation,the concept of reducingfuturelossesin the process of recoveryfromfloodswashonoredmorein the breach than in the observance.Itiswellknownthatcommunitiesstrickenbyfloodsandotherdisastersseek torestorethestatusquoanteasquicklyaspossible.Duetotheirphysical nature, floods tend tobeviewedasonce-in-a-lifetimeevents, or"actsofGod,"whichareunlikelytorecur in thesamelocation.Sucha viewpointiscontradictedbyactualhistory.HurricaneAgneswasviewedasa once-in-500-years event for the regionitdevastated,yetmanyof thesamevictimswereflooded againbyHurricane Eloise in 1975.ThePearl RiveratJackson, Mississippi, displaced 6,000 people inDecemberof 1961. Despite a massiveCorpsof Engineers levee, completed in1967,the Pearl surpassedits1961crestbyfivefeetin April of 1979, displacing 17,000 peopleandcausinganestimated$500million indamagetothe City of Jackson(Platt,1982).TheCity of Houston, Texas, experienced three "100-year floods"in1979alone. National dataonrepetitivelosses to thesamestructure,neighborhood, orcommunityaredifficultto assemble.Recordsof the Federal Disaster Assistance Administration, however,indicatethatbetweenJanuary 1,1972andAugust31,1979,some2,000 communities experienced "major flooddisasters"declaredbythe presidentontwoormoreoccasions. Three ormoremajor floodsweredeclared in351communities(FederalEmergencyManagementAgency,unpublisheddata).Thedecade of the1970switnessed asignificantshiftin national flood policy,awayfromrelianceuponstructuralmeasuresandtoward nonstructuralefforts,including: floodplainregulations,floodproofing,acquisitionandrelocation,improvedwarning systemsandemergencyplanning.Ironically,thisshiftinvolved a subtle downgrading of public recognition of therecurrentnature of floods. Proponents of federalstructuralflood controlprojectstended to emphasizeandevenexaggerate the propensity for floods to recur in thesamelocation.Conversely, the nonstructural measureslistedabove,whichinvolve unpopularpoliticalandfiscalactionbylocal governments,mayhaveled to a tendency to underestimate theprobabilityofrecurrence.Inanyevent, reduction of future losses through floodplainmanagement,while environmentallyandfiscallysoundinmanycases, requires actionbycountlessdiscreteunitsof local government incontrasttothecentralizedauthorityof the federal government with respect to flood controlprojects.

PAGE 95

84POSTFLOODMITIGATIONThustheshifttononstructuralmeasures involved adecentralizationof public decisionmakinganda concomitant tendency todenythe recurrent nature of floods. FindingsoftheCaseStudies, IncludingBigThompsonAnassessment of thestateof theartof postflood recoverywasconducted through aseriesof casestudies,Theseincluded:RapidCity,SouthDakotaFlashFloodof1972BigThompsonCanyonFlashFloodof1976SoldiersGrove,Wisconsin Charles RiverWatershedin MassachusettsPrairieduChien, WisconsinLittleton,ColoradoBaytown,TexasSnohomishBasin,WashingtonClinchport, Virginia Massachusetts CoastalFloodof1978Jackson, MississippiFloodof1979Baltimore County,MarylandSaltCreekBasin,IllinoisAmongthe above, themostdetailedattentionwasgiven toRapidCity,BigThompson,the Charles River Watershed, SoldiersGrove,andPrairieduChien. (Subsequent researchonthe Massachusetts CoastalFloodof1978andJackson, MississippiFloodof1979waspublished in1980and1982,respectively.)ThelossanddamagestatisticsofBigThompsonCanyonare adequately described in other papers inthisconference. I will therefore turndirectlyto thepostdisasterrecovery experienceofthatcatastrophe. AsidefromRapidCity in1972,fewifanyU.S.flooddisasterspromptedsucha comprehensiveandsearching investigation oftheircauses or plansofremedial action.Inparticular,a task force establishedbyGovernorRichardLammwithin hours of the July 31,1976flood, conducted a thoroughinvestigationof causesandactions for recovery.Thetask forceinitiallyrecommendedpublic purchase of theentirecanyonto preemptanyprivate rebuilding. Thiswouldhavebeena demonstra tion project in nonstructural postflood mitigation, comparable to theRapidCity approach. Totalacquisition,however,did nothappeninBigThompsonCanyon.Instead, amorelimited acquisition program, involving123parcels of landinterspersed with private inholdingswaseventuallybegunbyLarimerCountywithassistancefromthe Department ofHousingandUrbanDevelopmentandthe Department of theInterior.Thecounty adopted flood plain zoning to guide rebuilding in the canyon,

PAGE 96

Platt85butasiswellknown,reconstructionwaswidespreadandinvolved high-value investmentswhichremainatrisk.According to dataavailablein1979,thetotalfederal outlayfornonstructural measures to promoteacquisition,relocation,andrehabilitationcomprised a smallfractionoftotalfederal recoveryassistanceinBigThompson:$1.6 million out of the $45.6 milliontotal.Includingallocationsofstateandcounty funds, atotalnonstructural budget forBigThompsonCanyonamountedto $2.2 million (Figure1).Eventhispaltryamounthadtobepainstakingly assembledfromdiverse federal sources.Themajorcontributionswereobtainedfromthe sourceslistedin Table1.Eachof these required extensive negotiationsandpoliticalstringpulling.Thetangibleoutcomeobtained withthis$2.2 million involved theacquisitionof123parcelsoflandfrom97owners,totalingabout50acres.Thiswasaccomplished over a period ofmanyyears, with considerable unhappinessanduncertainty for the property owners,manyofwhomwereflood victims.Dozensof other parcels remained inprivateownershipandwererebuilt,oftenatconsiderablygreatervalue than before the flood. This created a checkerboardpatternofprivateandpublic holdings.ViewingBigThompsonin conjunction with the other casestudies,the following findingsweremade: Nonstructural outlays for postflood mitigationweretrivialin comparison with federal investment inrestorationofinfrastructure.Inthe absenceofa federal policy orfundto promotenonstructuralpostfloodmitigation,sucheffortstended tobeadhocandfrag mented, dependinggreatlyupontheinitiativeandpoliticalsophisticationofstateandlocal publicofficials. Delay in achievinganynonstructural mitigation elementwaspervasive,thus adding to the emotionalandeconomicburden to victimsandcomplicating the workload of recoveryofficials.Inthe absence of asinglesource of federal nonstructuralassistance,"packaging" of diverse sourceswasgenerally required. (See,e.g.,anexcellentcase studyofSoldiersGrove,Wisconsin preparedbyDavidandMayer,1984.) Federal agenciesthatassistednonstructuralmitigation generallywereinconsistentastoproceduresandcost-sharing requirements.

PAGE 97

86POSTFLOODMITIGATIONCashflow problemswerecommon,resultingfromdelay in federal reimbursement ofstateandlocaloutlays."Checkerboarding,"asinBigThompsonCanyon,isa frequentoutcomeof piecemeal publicacquisitioneffortsleading todifficultissuesarisingfromthejuxtapositionof publicandprivateholdings.RecommendationsandOutcomeof the1979Study Several recommendations toimprovefederal policy regarding postflood hazard mitigationwerepresented in the report to theU.S.WaterResources Council(Platt,1979). Aseriesofinter-relatedadjustmentsandactionsweresuggested.First,itisimperative for a hazard mitigation coordinatortobeappointed for eachdisasteronceapresidentialdisasterdeclarationhasbeenissued.Thecoordinatorwouldbeauthorized to serveasa "one-stop shopping" agentonbehalf ofallrelevantfederal programs tofacilitatethe flow of mitigationassistanceLothedisasterarea. Second, apromptassessmentofoptions forpostdisastermitigationmustbeundertaken following adisasterdeclaration.Ideally,a preliminaryreportonopportunitiesformitigating future losses shouldbeprepared within sevento15days following thedisasterdeclaration.Thiswouldserveasa guide tofederal,state,andlocal recovery actionsandpolicies.Third, to conductthisassessmentandto advise the coordinator, apostdisasterhazardmitigationteamshouldbeestablishedin each federal region.Theleadagencyforsuchteamsshouldbethe FederalEmergencyManagementAgency(FEMA).Theteamsshould includerepresentativesfromotherrelevantfederal agencies,aswellasthestateandlocal governments,andperhapsprivateinterestsin thedisasterarea.Teammembersshould receivepriortrainingin proceduresandobjectives.Theyshouldbeavailableto reportonthe scene of a flooddisasterwithin hours of adisasterdeclaration.Fourth, tofacilitatethe organization ofsuchpostdisasterteams,12federal agencies involved in postflood recovery shouldenterinto a formal, interagency agreement to cooperate inestablishingsuchteams.Theserecommendationswereacteduponpromptly.Dr.FrankThomasof theU.S.WaterREsources Council relayed the recommendationstothe Office ofManagementandBudget,whichissued adirectiveonJuly 1,1980,to the12federal agencies to executeaninteragency agreementascalledfor in thereport.Theagreementwas

PAGE 98

Platt87signedonDecember8,1980,andwentintoeffectimmediately.FEMA,aslead agency,initiatedthe designationandtrainingof posthazard mitigationteamsin each ofitsregions.Italso contracted withWrightWaterEngineering,Inc.,in Denver, to prepare amanualof procedures forusebythe teams. Since1980,postflood hazard mitigationreportshavebeenprepared for approximately75declared flooddisasters.Thereportsprovide a unique record of data concerning each flood,aswellasrecommendations for recoveryactions.Current StatusandIssuesHasthe hazard mitigationteamprocessmadeanydifferencein thewaywerecoverfromfloods?Ananswer tothisquestionwouldrequire a thorough review of experience in across-sectionof the75+floodsthathaveoccurred since the procedureswasinitiatedin1980.Sucha reviewhasnot yetbeenundertaken, although a small survey of fourdisasterswasconductedbyWrightWaterEngineersin1983.This chaptercanonlylistcertainissuesthathopefully willpromptsubse quentinqulrles.First,howeffectivelydohazard mitigationteams(HMTs)perform?The1983WrightWaterEngineers reportfoundaconflictbetweenteammembers'loyaltytotheirownagency versus amorecomprehensive visionofpostdisastermitigation.Thelatterisadesirableobjective,onethatisrarein the experience of the federal bureaucracy. Pursuit of narrowagencymissionswouldundermine the usefulnessoftheHMTprocess. Second, acloselyrelatedissue concernshowteamsresolvedifferencesamongmembers.DoHMTreportsstrivefor consensus through agreementupontheleastcommondenominator,ordothey presentmorechallenging options, perhaps with minorityviewsincluded? Third,howisdata assembledandpresented inHMTreports? Shortage of both timeandfunds severely constrains theabilityofteamsto acquire necessary physical, demographic,andeconomicdatauponwhichto basetheirrecommendations.Itwouldbeusefultoestablishregional resource centers (perhaps inuniversitydepartments of geography)whichcould develop computerized databasesandmappingprogramstobeavailableto hazard mitigationteamsonshortnotice.Fourth,howhaveHMTreportsbeenpublicized,andwhathasbeenthe public reception?Ifthe processisto bearfruit,theremustbeopportunityforpublic discussionandrevision of recommendations. This presumably requires presentations toestablishedbodies,suchascitycouncils,aswellasgeneral public hearings.

PAGE 99

88POSTFLOODMITIGATIONOfcourse, aconflictofobjectivesexistsbetweenpreparing a timelyreportdetailingspecificoptions versus providing opportunityforfull,opendiscussionpriorto completion of thereport.Fifth,thereappearstohavebeenlittleprogress towards designating a hazard mitigation coordinator.TheDisasterCoordinatingOfficer(DCO)appointedbyFEMAfor eachdisasterisonlyincidentallyconcerned withmitigation.TheHMTitselfgenerally meets only afewtimes,anditsmembersquicklyreturntotheirotherduties.Insomecases, theteamleader--typicallyaFEMAregional staffperson--may continuetofunction forsometimeasanadhochazardmitigationcoordinator.Theextent towhichthisoccursanditsresultsshouldbedocumented. Sixth, the use of moratoriabystateandlocal governments to delay thestartof rebuilding pending recommendations of theHMTisunclear.Evenunder ideal circumstances, publicationanddiscussion of theHMTreportwouldrequireatleastamonthafterthedisaster.Itispoliticallydifficult,althoughlegallypossible,to hold the victims of the flood in limbo whilesuchdiscussions proceed.Obviously,alternativearrangementsmustbemadefor housingandcompensating the victimssothatgovernmental proceduresdonotaddtothe burdeninflictedbythedisasteritself.Withoutanydelay for consideration of rebuilding options,even themostsensiblepostflood mitigation options willbeunachievable. Seventh, towhatextentcanpostdisastermitigation planningbeaccomplished before a flooddisasteroccurs?Thesuccess of theRapidCity recovery processresultedfromthe existence ofanurban renewal planwhichanticipatedthe acquisitionandrelocationofallfloodplainoccupants. Other flood-prone communities shouldbeencouraged to prepare contingency plans ofgreaterorlessdetailtobeimplemented in the event of adisaster.Theextent towhichthisisnowoccurringisunknown.Finally,availabilityof federal funding for postflood mitigation apparently remainsmodestin comparison with overalldisasterassistance.Thereisstillnofundearmarked for flood mitigation recovery. Efforts to acquirepropertiesthrough Section1362of the NationalFloodInsuranceProgramhavebeenminuscule, amounting to about$5million per year.Theneedto reduce future federaldisastercosts stronglyindicatestheneedfor a reasonable investment inmakingcommunitiessaferwhenfloods occur.

PAGE 100

Platt89ConclusionThe1979WaterResources Council study ofpostdisastermitigation yielded asignificantchange in federal policy. Withinmonthsafteritscompletion,all of the12federal agencieshadagreed (asdirectedbythe Office ofManagementandBudget) to cooperate in the establishment of postflood hazard mitigation teams.Theflow of preliminaryandfollowup reportsfromtheseteamsconcerningsome75floods since1980nowoccupies about threefeetoflinearshelfspace.Theeffectsin terms of actions taken or not takentoreduce futurevulnerabilityare notclear.Research shouldbeundertaken toascertaintheimpact,ifany, of theHMTprocessandtorecommendappropriate refinements toitsprocedures. References David,E.andJ.Mayer.1984"ComparingCosts of AlternativeFloodHazardMitigation Plans:TheCaseof SoldiersGrove,Wisconsin." JournaloftheAmericanPlanning Association 50,pp.22-35.Platt,R.H.1979Options toImproveFederal NonstructuralResponsetoFloods.NTISHPB80-160146. Washington,DC:U.S.WaterResources Council.1982"TheJacksonFloodof1979:A Public PolicyDisaster."Journal of theAmericanPlanning Association 48,pp.219-231.Platt,R.H.andG.M.McMullen1980Post FloodRecoveryandHazardMitigation: Lessonsfromthe Massachusetts Coast, February,1978.PublicationHIlS.Amherst: University of MassachusettsWaterResources Research Center. Wright Water Engineers, Inc.1983AnalysisoftheHazardMitigationTeamProcess. Denver:WrightWaterEngineers, Inc,

PAGE 101

Fiqure1BIGTHOMPSONCANYON,COLORADOJULY31.1976FLASHFLOODRECOVERYPROGRAMFEDERALASSISTANCE !. IN $MILLIONSI-NONSTRUCTURALMEASURES c.. ACQUISITION.RELOCATION.REHABILITATIONFHWA(HighwayRepair)$20.4FDAA(allprograms)$11.20$7.20TotalFederalAssistance$45.6MillionFederalShareofNonstructural (seeTable2forsourcesandamounts)TotalNcnstructural$2.2 Million NOTE:CIRCLESNOTTO 8AME 8CALE

PAGE 102

TABLE1SOURCESOFLANDACQUISITION& RELOCATION FUNDSOriginalFinalCostAuthority*A.HUDCDBG$716,347$944,000B.LWCFDiscretionaryFund574,169747,600C.LWCFColoradoShare203,837265,000**D.FourCornersReg.Cornrn. US,145 150,000E.StateofColorado561,721730,959H.R.1250(1978)F.LarimerCompany101,140 131,641Totals$2,272,359$2,969,200*Includes$811,000HUDDisasterFundsand$133,000HUDDiscretionaryFunds.**Federalfundsusedaspartof"non-federal"matchtoLWCFgrantasapprovedbytheCommission.UnusedAmount$227,658173,43061,16234,854169,23730,500$696,841

PAGE 103

INNOVATIONSINTHEPRIVATEHANDLINGOFFLOODINSURANCEWilliamM.DyeInsurance Consultant IntroductionFloodinsuranceistoo frequently overlookedasoneof themostimportant mitigation measures forflood-relatedpropertydamage;ithasyetto reachitsfullpotential.This chapter will describesomeof the major problems facedbytheprivateinsurance companies in providing coverage forpropertieslocated in flood prone areas.Ofnecessity,the federal governmentwasforcedtostep inandprovide the coverage.Now,manyprivateinsurance companies areparticipatingin aprogramsponsoredbythe Federal Insurance Administration to provide flood insurance.Onlyafewprivatecompaniesoffera catastrophe insurance programthatincludes coverage for floods.Inspiteof the progressmadein theavailabilityandtheaffordabilityof flood insurance, aboutthreeout of fourpropertieslocated inidentifiedflood hazard areas arestillwithout flood insurance. Uninsured victims will continue tobeafinancialburdenontherestofsociety.Soon,pressure will buildtorequireallproperty insurancepoliciesto include coverage for flooddamage.Inthemeantimeandasafirststep,the authorrecommendsthatprivateinsurance companies include flood coverage inallhomeownerspoliciesforpropertieslocated in areaswherethe flood hazardhasbeendesignatedasminimal(ZoneC).FloodInsurance Flood insurancehasbeenclassifiedasa mitigation measure. Mitigationismoderation in the force, violence, orintensityof somethingpainful.Reliefisasynonymfor mitigationandsuggests theliftingofenoughof a burden tomakeitendurable.Floodinsurancefitsthedefinitionof amitigationmeasure.Itsprimaryeffectisafterthefact,whenthe survivors returntotheirflood-damaged propertyandtryto put everything back together again.

PAGE 104

93Unavoidable RiskandUnaffordableLossIfyoubuild yourdreamhousealong thebanksof a running stream,youcouldbefaced with the unavoidableriskof future flooding.Itisonly a matter of timeuntilaheavydownpourcauses the water level toriseandoverflow thebanksof the stream.Andifyouare ofmodestfinancialmeans,youcouldbefaced with the unaffordablelossto your propertyfromflooding.Forthe unavoidableriskandthe unaffordableloss,society'susual responseissomeformof insurance.Inthisparticularcase,itisflood insurance. PurposeandFunctionThebasic purpose of flood insuranceisto provide protectionfromthefinancialconsequences ofdamageto your property causedbyflooding.Thebasic function of flood insuranceisthetransferofrisk(chance of loss)fromthe individual propertyownerto the insurancecompany.Inreturn forpaymentof asetpremium,the insurancecompanyagrees tobefinanciallyresponsible foranyfuturedamageto the property causedbytheperilof flood.Floodinsurancecanreduce the uncertainty of future lossesbymakingthe unavoid ableriskandthe unaffordablelossfromflooding manageable. Thatis,theunknownriskandlossof the futureisreplaced with aknownpremiumpayment.Ifyouhavecoverage for a floodlossto your property, the insurancecompanyisfinanciallyresponsible for indemnification.Itistheirresponsibilityto putyouback in thepositionthatyouwerein before thelossoccurred--nobetterandnoworse.FloodInsuranceandCatastrophesOnereasonprivateinsurance companies avoid writing flood insuranceisthepossibilityof a major catastrophe.Allproperties concentrated in aparticulararea couldbesubjectto atotalloss--forexample, thepropertieslocated along thebanksof theBigThompsonRiveronJuly 31,1976.Usually, the only peoplewhowillvoluntarilybuyflood insurance are theonesmostlikelytosufferaloss.Thecoveragewouldappeal to thehomeownerin a flood hazard area but not to thehomeownerwholivesuponahill.Forthe insurancemechanismtowork,youneeda reasonable spread ofrisk.Manypeople couldbeexposed to theperil,but only a veryfeware expected tosufferaloss(forexample, atotallossbyfire).This conceptdoesn'tworktoo

PAGE 105

94FLOODINSURANCEwell with flood insurance.Fromaninsurance company's standpoint,youdon'twantto put toomanyeggs inonebasket. Social Responsibility vs.SelfInterestWiththetransferofrisk,reduction inuncertainty,andthe provision of indemnification, flood insurance appears tobethe simple answer for peopleowningproperty exposedtotheperilof flood. People withthisexposureneedflood insurance.Youwouldthinkprivateinsurance companieswouldhavea social responsibilityto provideit.Thenagain, faced with majorcatastrophes,adverseselection,andnospread ofrisk,privateinsurance companieshavetheirownselfinterestandsurvival to consider.Justonecatastrophicflood couldwipeoutmostof a company'sassets.DisasterReliefvs.FloodInsurance Without flood insurance, the uninsured victims of a flood could looktotheRedCross for emergency food, clothing,andshelter.Thelocalcity,county,andstategovernments could providereliefandwelfare support.Thefederal government could provide specialgrants,lowinterestloans,andevenanincometaxwrite-off.Thefinancialburden of a flooddisasterwouldshiftfromthe uninsured victimstosociety.Withpopulation growthandmarginal land in flood -prone areas put to use,morepeople are exposed to floodloss.TheoptionforCongress to considerwastoeithercontinue fundingdisasterreliefprograms or provide a government-sponsoredandsubsidized flood insurance program.Then,people withthisexposure couldbuyflood insuranceandtake care ofmostoftheirfuturelossestoproperty. NationalFloodInsuranceProgramTheNationalFloodInsuranceProgramwasenactedbyCongress in1968asanalternativetodisasterrelief.Inreturn for providing flood insuranceatsubsi dizedrates,communitiesparticipatingin theprogramare requiredtoimplement floodplainmanagementmeasuresandminimize future development in flood-prone areas.FloodDisasterProtectionActTheFloodDisasterProtectionActwasenactedbyCongress in1973.This act requires the purchase of flood insurance forfederallyinsured loans secured for the

PAGE 106

95acquisitionorimprovementofstructureslocated inidentifiedspecial flood hazard areas. This requirementwouldinclude loans insuredbysuchfederal agenciesasthe FederalHousingAdministration(FHA),Veterans Administration(VA),andtheSmallBusiness Administration(SBA).About90%of thenewapplicationsreceived for flood insurance are submittedtosatisfythisrequirement. WriteYourOwnProgramAsof October, 1983,privatepropertyandcasualty insurance companiescansignanagreement with the Federal Insurance Administration tosellandservice flood insurancepolicies.Asof July 1,1986,260privateinsurance companieshavesignedthisagreement,andjoined the WriteYourOwnProgram. Private companiescollectthe premiums,paytheiragents a commission,andadjust floodlosses.Theparticipating companies use the NationalFloodInsurance Program'spolicies,forms,rates,andunderwritingrules.Ifprivatecompaniespayoutmorein expensesandclaims than they receivedfrompremiumsandinvestmentincome,the federal government willmakeupthedifference.However,iftheprivatecompanies take inmorefrompremiumsandinvestments than theypayoutfor expensesandclaims, thedifferenceor netprofitisrefunded to theU.S.Treasury. Private Catastrophe Insurance PlansTheColorado Catastrophe Planisanexampleof aprivateinsurance plan toprotectahomeownerfromlosses causedbycertainperilsthatare usually excluded under ahomeownerspolicy. Protection providedwouldinclude coverageforfloodandearthquake.Thepolicyislimited to owner-occupiedresidentialdwellings. Licensed agents in Coloradocanwritethispolicy through the Western Insurance Markets of Denver.TheHomeownersCatastrophe Insurance Trustisanotherexampleof aprivateinsurance plan to provide coverage for floodandearthquake. This policyisalso limitedtoowner-occupiedresidentialdwellings.Membersof the Independent Insurance Agents of Coloradocanwritethispolicy through Trustco, Inc. ofSaltLakeCity, Utah.HomeownersPolicy Coveraoe/ExclusionsTheHomeownersSpecialForm(HO-3)isthemostpopularhomeownerspolicy.Thedwellingisprotected againstrisksofdirectphysical loss(allrisks).However,

PAGE 107

96FLOODINSURANCEdamagecausedbyfloodisexcluded unlessfireorexplosion ensues,andthen only the ensuinglossfromfireor explosionwouldbecovered.TheSpecial Personal Property Coverage(HO-I5)isanendorsementthatcanbeattachedtoaHomeownersSpecialFormPolicy.Theendorsement covers personal property locatedawayfromthe residence premisesdamagedbyflood.TheScheduled Personal PropertyEndorsement(HO-6I)canalsobeattached to aHomeownerspolicy. This endorsement provides coverageforrisksofdirectphysicallosstoitems of personal propertythathavebeenspecificallyidentifiedanddescribed. This endorsement couldbeusedfor insuringsuchitemsasjewelry,furs,musical instruments, coincollections,etc.Floodisnot excluded inthisendorsement. Therefore, items of personal property described in the endorsementwouldbecovered forlossduetoflood. Coverage Options--Concurrent Causation/LitigationManypeoplewhopurchaseso-called"allrisk"coverage under ahomeownerspolicy are disappointed to discoverthatflooddamageisexcluded. Creative lawyershaveturnedtothe legal doctrine of concurrent causation. Thismeansifalossto propertycanbeattributedtotwocauses--one coveredandoneexcluded, the policymustpaytheloss.Forexample, vandals cause a breach in adam(vandalismiscovered)andthevalleybelowisflooded (excluded).Thedoctrineof concurrent causation,ifapplied,wouldrecommendpayment.Whenyoudiscovered yourhomeownerspolicy excluded flooddamage,did your agentsoadviseyou?Ifso, did your agent also adviseyouof theavailabilityof flood insurance through the NationalFloodInsuranceProgram?Ifnot,anoption to considerisa lawsuitagainst your agent.Whenyoubuiltyournewhomein a special flood hazard area, did thecity/countybuilding department adviseyouofpossible flooding?Doesthecityor countyhaveanordinance toprohibitnewconstruction in flood-prone areas?Ifnot,anoption to considerisa lawsuit against yourcityor county government. InnovationsToConsiderTheconsensusamongmostpeople concerned with the problems describedaboveisthattheremustbeabetterwayto compensate the victimsofa flooddisaster.

PAGE 108

97CompulsionEvennow,about three out of four peoplewhoknowinglylivein a flood hazard areastilldonothaveflood insurance.Forpeople withthisexposure, therehastobeanelement of compulsion to requirethemtohaveflood insurance.Andto avoid adverseselectionandprovide for the spread ofrisk,itshouldbemandatorythatallproperty insurancepoliciesinclude coverage for theperilof flood.HomeownersCatastrophe CoverageThemostpopular plan proposed for catastrophe insuranceistoinclude coverage for theperilsof floodandearthquake inallhomeownerspolicies.Thepolicieswouldbesoldandservicedbyprivateinsurance companies but withsomefinancial back-upfromthe federal government. Pressureisbuilding forsucha catastrophe insurance policy.However,change will notcomevoluntarilyfromthe insurance industry. Rather than appeal totheirsocialresponsibility,youneedto develop aprogramthatwouldappeal totheirself-interest.Atthemoment,the insurance industryisplagued withmorepressing matters forsurvival,andcatastrophe insuranceforthe averagehomeownerisnot highontheirlistofpriorities.InnovativeFirstStepAninnovativefirststepwouldbeto include coverage for theperilof floodinallhomeownerspoliciesfor properties located in areaswherethe flood hazardisdesignatedasminimal(ZoneC). Usually, thereisnorequirement forpropertieslocated inZoneC tohaveflood insurancej however, thereissomepossibilityof flooding.TheNationalFloodInsuranceProgramandthe Write yourOwnProgramwouldcontinue to insurepropertiesin flood hazard areas designated as specialandmoderate (Zones A&B).Suchaninnovativefirststepisworthyofconsiderationbythe insurance industry.

PAGE 109

ThispageISblank

PAGE 110

PARTTHREEFORECASTINGINNOVATIONS

PAGE 111

ThispageISblank

PAGE 112

THENWSFLASHFLOODPROGRAM:THEPRESENTANDTHEFUTUREJamesD.BelvilleandRichardA.WagonerOffice of Meteorology NationalWeatherService IntroductionInordertolookatthe present NationalWeatherService(NWS)FlashFloodProgram, a lookatpast eventswhichinfluenced theprogramisnecessary.Inthe decade of the60sand70s,disastrousflashfloods struckRapidCity(NOAA,1972);KansasCity(NOAA,1977);BigThompsonCanyon(NOAA,1976);andJohnstown(NOAA,1977). Thesetragiceventsandothers provided the impetus for improving thepredictionanddetectionofheavyrainfalleventsandsubsequentflashfloods.Ithasbeenshownthatflash flood events arerelativelysmall scale(Maddoxeta1.,1979)andpresentoneof themostdifficulttasks facing theNWSforecastertoday.Themeteorologicalandhydrological data generallyavailableweredesigned forlarger-scaleevents. Thus,itisnotuncommonfor aheavyrainfallevent to occur unexpectedly.Makingarathercrude assessment ofverificationofthe FlashFloodProgram,itwasfoundthatone-half of theknownflashfloods occurred without thebenefitof aflashfloodwatchor warning.However,a comparison of the flash floodprogramof theearly70stothatof the mid-80sshowsthatvast impro,e mentshavebeenmade.NWSPresentDayFlashFloodOperationsThepresentdayNWSFlashFloodProgramismultifaceted in scope(Barrett,1983)andeach aspect willbediscussedbrieflyinthissection.Programareas included areradar,satellite,LocalFloodWarningSystems(LFWS),andfore,cast techniques.Itshouldberememberedthatallof these are designedto functionasa means,notanend.RadarProgramTheradarprogramhasbeenthebackboneofflashflood operations for l11iil!1y years.Overthe pasttwodecades, advanceshavebeenmadewhich haveimpro,e,!!:"e flash flooddetectioncapabilitiesof radar.In1972,Smithand Koore(]979J developed the concept of manuallydigitizingradar data.This tedmi!;uegale

PAGE 113

102FLASHFLOODforecastersthecapabilityof determining thepersistenceofheavyrainfallinanareaandprovided themeansformakinga gross estimate of theamountofprecipitationoccurring.MDRdataispresently being preparedbyallNWSradarfacilitiesandhasbeenusedsuccessfullyduringnumerousheavyrainfallevents.Intheearly1970s, computerswerelinked with fiveNWSradarsandusedto process the radarreflectivitydata forusein estimatingrainfallamounts.TheDigitizedRadarExperiment(D/RADEX)converted radarreflectivitiestorainfallrates.Theaveragerainfallisthen accumulated over aspecifiedtime period.Thesedata are in turn displayedonamapwith athree-byfive-milegrid.Intheearly80s, theRadarDataProcessor(RADAP)wasexpanded to include tenNWSradarsites.In1983,anInteractiveColor Display(ICRAD)wasintegratedwith theexistingRADAP.Thismadeamoreusable analysis tool for theNWSforecastersat these tensites.Animportant discoverythatoccurred in1985wastheQuasi-stationaryRainfall Signature(QRS)(MaddoxandGrice, 1985). This enabledforecasterstoaccess thepotentialforflashflood-producingrainsbyidentifyinga radarsignature,characteristicof aheavyrainfall-producingstorm,asisdonein theNWSSevereWeatherWarningProgram.SatelliteAnalysisProgramTheinception of frequent, highqualitysatelliteimagery in theearly70sprovided anewdimension to theNWSFlashFloodProgram. Techniqueshavesincebeendeveloped to estimaterainfallamountsfromsatelliteimagery (ScofieldandOliver, 1977). Digitized enhancementsshowingblackbodytemperatures of cloud tops areusedona half-hourly basis to assessrainfallrates.Also,certainstorm characteristics,suchasovershooting tops, mergingcells,cloudlinemergers,aswellasenvironmentalcharacteristics,areusedtoinflatetheinitialrainfallestimates.Intheearly1980s, the Scofield-Oliver techniquewasadaptedtoanInteractiveFlashFloodAnalyzer (IFFA). This computerinterfaceallowsforecastersin the Synoptic AnalysisBranch(SAB)atthe National Meteorological Center(NMC)to providereal-time,satellite-generatedrainfallestimates toNWSfieldoffices.Theestimates are not only important to the FlashFloodProgram, buthavegiven theNWShydrologicalforecastprogramquantitativerainfalldata in areaswherenoneexisted before.

PAGE 114

BelvilleandWagoner103LocalFloodWarningSystemsTheLFWSvary insophisticationfrommanualself-helptostateof theartautomated systems (Hydrology Subcommittee, 1985).However,allof these systems serve thesamepurpose.Theyallow localemergencymanagementofficialsto assessflashfloodpotentialin a timelymannerduringanongoing event.Initially,LFWSswereself-helpsystems consisting of rain gauges,staffrivergauges,andflashfloodforecasttables.Whenconsidering thelowcostofsuch # system, thereturnsfor the investment in terms oflifeandproperty saved aregreat.Drawbackstothistype of system arethattheneededdatamaybedifficultto obtain duringheavyrainfallifphoneserviceisdisrupted, or in areaswhereobservers cannotbefound.Inthemidtolate70s, the AutomaticLocalEvaluation in Real-Time(ALERT)System(BurnashandTwedt,1978)andthe IntegratedFloodObservingandWarningSystem(IFLOWS)weredeveloped.Thestateof thearttechnology incorporated in these systems allows sensors (bothriverandrainfall)tobeplaced in remote areas. Thesensors transmit the databyradio to a computerfacilitylocated inanEmergencyOperation Center(EOC)orNWSoffice.Thecomputer evaluates the data inreal-timeusing ariverforecastmodel.Forecastscanbeupdated every15minutesifneeded. This type of technology allowsemergencymanagementofficialstomakecriticaldecisions in a timelymanner.LFWSshaveworkedwell in the areaswheretheyexist.However,a major proble isthatthe localNWSofficecannot access theALERTdataeasily,anditisthe NWS thathasthe resources to disseminatecriticalflash flood warning information. Another drawbackisthatthe cost ofsucha systemmaypreventanareafromobtairingthistype of technology.NWSForecast TechniquesTheNWS,along with the National OceanicandAtmospheric Administration's(NOAA)Environmental Research Laboratory(ERL)havemadestridesin developing techniques for forecastingheavyrainfallevents during the past10years.Themeteorologicalpatterns,both surfaceandupperair,thatproducethevast lIajorit} offlashfloodshavebeenidentified(MaddoxandChappel, 1979). In addition,variationsin the basicpatternsfromonepartof the UnitedStatesto another beennoted (GriceandWard,1983;GiordanoandFritch,1983; Belvine and Ste,.,arL 1983;andGoodmanetal.,1983).

PAGE 115

104FLASHFLOODTheconcept of issuinglocalizedQuantitativePrecipitationForecasts(QPF)wasdevelopedattheNWSofficeinLubbock,Texas, in1975(Belvilleetal.,1978). This conceptwasupdatedandimprovedin thelate70s(Mortimeretal.,1980).Thetechniques used inTexasweresuccessfulenoughthatsimilarstudiesarenowunderwayin several sections of the country. Anotherstridehasbeenmadeinidentificationandstudy of mesoscale convectivecomplexes(MCC)(Maddox,1980;FritchandMaddox,1981;andMaddoxetal.,1981).MCCsare midlatitude systemswhichmostoften occuratnightandare generally accompaniedbyveryheavyrainfall.Hence,flashfloods oftenaccompanyMCCs.Sincemostheavyrainfallsystems are mesoscale in nature,itisimportant forNWSforecasterstouse mesoscale analysis techniques fordetectingsuchevents. Yet, almostallNWSstandard analysisandnumericalforecastmodelsareonamuchlarger(synoptic)scale.Thelargescale analysesandmodelsseldomdetectorforecastaflashflood. A recently developed objective analysis technique (Bothwell,1986)hasproved valuable for mesoscale systems.TheanalysisisrunontheNWSAutomation of Field OperationsandServices(AFOS)computer, towhichallNWSofficeshaveaccess.Themesoanalysisprogramprovidesfieldsof various meteorological parameters(i.e.,moistureandatmosphericstability)whichare important for the development ofdeepconvection.NWSFuture FlashFloodOperationsTheNWSisslatedto undergo a vast modernizationandrestructuringprogramduring the next decade.Theoverallbenefitwillbeto streamline operationsandincrease theefficiencyandaccuracy of the forecastandwarning program. Thisisexpected tobeaccomplished with a combination ofnewtechnologyandreallocationof presentdayresources.Whenreadingthissection,itshouldbekept inmindthatafewof the items discussedhavebeenfunded, while others are conceptswhichhavenotbeentranslatedintofundedprograms.RadarProgramTheNWSradarprogramof the future will continuetobeextremely important to the FlashFloodProgram.However,NextGenerationWeatherRadar(NEXRAD)willbedeployed around the nation, beginninginthelate1980sandcontinuing through the

PAGE 116

BelvilleandWagoner105mid-1990s.NEXRADisdesigned tobeanentiresystem with thecapabilityof suppressing groundclutter,precipitationmapping,detection ofwindshear,computingverticalintegratedliquidwater in the atmosphere,anddisplaying cloudparticlevelocities.Themostimportant aspect ofNEXRADfor the FlashFloodProgramisprecipitationprocessing. Rainfallmapsestimatedfromradar willbegeneratedbythe systerr atintervalsspecifiedbytheforecaster.Inaddition, theprecipitationestimationprogramwillbecontinuouslycalibratedbycomparing the radarreflectivitiesto actualrainfallratesreceivedfromautomated rain gauges.NEXRADwill provide theNWSforecasterwith the highresolutionquantitativerainfalldata needed for flash floodprediction.SatelliteAnalysisProgramAnadvanced system of GeostationaryWeatherSatellites(GOES)will provide another major step inmovingthenation'sweather warningandforecastservice into the 21st century.ThenewGOESsystem will provide increasedreliability,higherresolutionimages,moreprecise location oflowlevel features suchasclouds,andthecapabilityof viewingandsounding the atmosphere simultaneously.Inthe realm of improving theNWSFlashFloodProgram,thenewGOESsystem, along withNEXRAD,will allow theforecasterto construct a three-dimensionalimageof aheavyrainfallsystem.Thesatellitesystem will also provide a high resolutionpictureofatmospheric moistureandtemperaturefields.This will in turn providebetterpredictivecapabilityfor flash floods.LocalFloodWarningSystemsThenumberofLocalFloodWarningSystemsisexpected to increaseratherdramatically over the next decade.TheNWSnewAutomatedWeatherInformationandProcessing System(AWIPS)thatwillbeimplemented in the1990sisbeing designed tc handle thelargevolumeof data generatedbyLFWSnowin existenceandthose expectedtobecreatedintothe 21st century.Itisexpectedthatinsomeareas technology willbeavailablethatwilllinktheLFWSdirectlyto dissemination systems, providing vastimprovementin timelinessandaccuracy offlashflood warnings.

PAGE 117

106FLASHFLOODNWSMeteorological TechniquesImprovedunderstanding of the physical processes in the atmospherethatcontribute toheavyrainfallwillresultdueto theeffortsof theNWSandthe researchcommunity.However,theimprovedconcepts will lead tobetterprecipitation forecasts onlyifincluded in the context of a mesoscale numerical forecastmodel.Itishopedthatsuchamodelwillbeavailable forusebyNWSforecasterswithin the next decade ortwo.Theintroduction of theAWIPSsystem will provide theforecasterwith themeansfor assimilatingandanalyzing the ever increasingamountof weather information producedbythenewtechnology. Thisinteractivecomputer system willintegratetheNEXRAD,satellite,andconventional data into aformthatisreadilyusable. This will enable theforecasterto scan largequantitiesof data in a timeframethatwill lead tomoreaccurateforecasts.AWIPSwilllikelyinclude theuseof knowledge-based expert systems forassistingtheforecasterin the decision-making process during periods of high flash floodpotential.TheAWIPSsystem will also provide themeansfor disseminatingcriticalweather information to both publicandprivate users.Thecoordination function with localemergencymanagementofficialswill alsobegreatlyimproved.AWIPSwill allowlocallygenerated graphics tobesent toEOCsandothers forusebyofficialsinmakingdecisions during periods ofcriticalweather. This could rangefroma radarmapshowingthe positionandprojected path of a tornado, to a model-generated hydrograph during a flash flood event.Itisplanned forAWIPStobethe nucleus of theNWSof thefuture.ConcludingRemarksWhathasbeenpresentedisanoverview of the NationalWeatherService todayandthatwhichshouldexistin the future.Asstatedpreviously, notallthatwasdiscussedhasbeenfunded,anditislikelythatmodifications willbemadeasaresultofchanging resources.However,theNWSisfaced withanexciting futurethatwill enable theforecasterto respond quicklyandpositivelyto flash floodthreats.

PAGE 118

BelvilleandWagonerReferences107Barrett,C.B.1983"TheNWSFlashFloodProgram."Pages9-16 inPreorints,FifthConferenceonHydrometeorology (Tulsa). Boston:AmericanMeteorological Society.Belville,J.D.,G.A.Johnson,andJ.D.Ward1978"AFlash Flood Aid--The LimitedAreaQPF."Pages21-28 inPreprints.AMSConferenceonFlash Floods(LosAngeles). Boston:AmericanMeteorological Society.Belville,J.D.andN.O.Stewart1983"Extreme Rainfall Events in Louisiana:The'NewOrleans' Type."Pages284-290 inPreprints,FifthConferenceonHydrometeorology (Tulsa). Boston:AmericanMeteorological Society. Burnash,R.J.C.andT.M.Twedt1978"Event-reporting InstrumentationforReal-time Flash Flood Warnings." Pages 96-100Preprints,AMSConferenceonFlash Floods(LosAngeles). Boston:AmericanMeteorological Society.Fritch,J.M.andR.A.Maddox1981"Convectively Driven Mesoscale Weather SystemsAloft.Part I: Observations." JournalofApplied Meteorology20,pp. 9-19. Giordano,L.A.andJ.M.Fritch1983"TheA-Typical Mid-levelFlowforFlash Floods in the Mid-AtlanticStates."Pages142-147 inPreprints,FifthConferenceonHydrometeorology (Tulsa). Boston:AmericanMeteorological Society.Goodman,R.R.,R.C.Charnick,andR.E.McNeil1983"ForecastingHeavyRains in Alabama."Pages279-283 inPreprints.FifthConferenceonHydrometeorology (Tulsa). Boston:AmericanMeteorological Society. Grice,G.K.andJ.D.Ward1983"Synoptic ConditionsofHeavyRainandNon-heavyRainEvents over SouthTexasAssociated with Tropical Cyclones." Pages 130-137 inPreprints,FifthConferenceonHydrometeorology (Tulsa). Boston:AmericanMeteorological Society. Hydrology Subcommitteeofthe Federal Interagency AdvisoryCommitteeonWaterData1985GuidelinesonCommunityLocalFloodWarningandResponse Systems. Washington,DC:U.S.GovernmentPrintingOffice.Maddox,R.A.1980"Mesoscale Convective Complexes."BulletinoftheAmericanMeteorologicalSociety 61, 1374-1387.

PAGE 119

108FLASHFLOODMaddox,R.A.,C.F.Chappell,andL.R.Hoxit1979"SynopticandMeso-alphascale Aspects of FlashFloodEvents." Bulletin of theAmericanMeteorological Society60,pp.115-123.Maddox,R.A.,D.J.Perkey,andJ.M.Fritch1981"Evolution ofUpperTropospheric FeaturesDuringtheDevelopmentof a Mesoscale ConvectiveComplex."Journal of Atmospheric Science 38,pp.1664-1674. B.,G.A.Johnson,D.G.Noble,andJ.D.Ward"AnImprovedLimitedAreaQPFforWestTexas."Pages141-148inPreprints,SecondConferenceonFlash Floods (Atlanta). Boston:AmericanMeteorological Society.andD.SmithManuallyDigitizedRadarData.InterpretationandApplication. TechnicalMemorandum,NWSSR-99.Ft.Worth,Texas:NOAA.BlackHillsFloodofJune9,1972,A Report to the Administrator. Natural DisasterSurveyReport 72-1. Washington,DC:NOAA.BigThompsonCanyonFlashFloodof July 31-August 1,1976,A Report to the Administrator. Natural Disaster Survey Report 76-1. Washington,DC:NOAA.1977Johnstown, Pennsylvania, FlashFloodof July 19-20,1977,A Report to the Administrator. Natural Disaster Survey Report 77-1. Washington,DC:NOAA.Moore,P.L.1979Mortimer,E.1980NOAA1972 1976Scofield,R.A.andV.Oliver1977ASchemefor Estimating Convective RainfallfromSatelliteImagery.NOAATechnicalMemorandumNESS86. Washington,DC:NOAA.

PAGE 120

HYDROLOGICMODELINGUSINGRADAR-RAINFALLIMAGERYLynnE.JohnsonDepartment of Civil Engineering University of ColoradoatDenverA flash flood forecasting systemisbeing developedwhichhasthreemainelements:1)high-resolution estimation ofrainfallin timeandspace using radarandground-based gauges;2)computermodelsof hydrologic response;and3)aninteractivecomputer graphic(ICG)system for datamanagement,analysisanddisplay.Linkageof radarrainfalldigitalimagerywithanICGwatershed datamanagementpackagehasbeenaccomplishedona desktop workstation. This chapter presentsanoverview of the flash flood forecasting systemandresultsofeffortsto linkspatialdatasetsdefiningrainfalldistributionandwatershed area. Introduction Short-term forecasts of intenserainfalleventscanaid hydrologistsandcommunityemergencypreparedness personnelinminimizingdamagesandsocial disrup tionassociated with flash flood events. Early warningcanprovide time for evacuating peopleandtheirvaluables.Optimumusecanbemadeof flood control systems inallocationof hydraulic control resources(e.g.,storageandflowcapacities).Suchreal-time responsesandcontrolstrategiesrequirethatforecastsbemadeofthespatialandtemporalcharacteristicsofrainfalldistributionover the watershed,andthatthe hydrologic response of the watershedandflowcontrolcomponentsare forecast. Aspects of the flash flood forecastingproblemwererecentlyidentifiedashigh-priorityresearchneedsfor flood mitigation(Changnon,etal.,1983). Included inthatreport arerecommendationsforimprovedremote sensingandflood warning networks, floodflowandstage prediction techniques,andtechniques for warning peopleatrisk.Improvementof local weather serviceisexpected toresultinsignificantreduction in deathsandeconomiclossesfromhazardous weather eventssuchasflash floods, tornadoesandhighwinds.Thesephenomenaoften occurinshort time framesandover small areas, conditionswhichmakedetectionandwarning

PAGE 121

110HYDROLOGICMODELINGdifficult.Flash floods ofthistype are aparticularthreatin therapidlyurbanizing Colorado FrontRange.Duetotechnological advances in several areas, thefeasibilityhasincreased forfurtherdevelopment ofaneffectiveandefficientcapabilityfor intenserainfalleventdetection;prediction of watershed runoffrates,volumes,andflood depths;andwarning ofcommunityflood preparednessauthorities.Anewgenerationflashflood forecasting systemispossiblewhichhasfourmainelements: Community-basednetworks ofrainfallandstreamflow gauges capable ofreal-timereporting; High-resolution estimation ofrainfallin timeandspace using advanced technology radarandanalysis techniques; Computermodelsof watershed hydrologic responseandhYdrologic databasemanagementtechniques; Interactivecomputing systems for data storage,retrieval,analysisandgraphicdisplay.CommunityFlashFloodForecasting SystemsTheprograms of the National Weather Service River ForecastSystem(NWSRFS)strivetoprovide timely floodforecastsandearlywarnings tocommunityauthoritiesandthe general public.TwelveRiver Forecast Centers(RFCs)coordinatecollectionof hydrometeorologic dataandprepareandtransmitforecastsandwarnings for approximately 2,500 communities nationwide.However,thiscentralizedsystemisprimarilydirectedtothe majorriversystems of the nation,sotheRFC'scapabilitiesfordetectingandreacting to intenserainfallevents over small watersheds(lessthan500sq.km)islimited.Forexample, storm eventswhichled to the extensive floods in Johnstown,PA;RapidCity,SD;andBigThompsonCanyon,CO,could notbereliablydetectedbya coarse network of reportingstationsandforecastcenters.Recently, anumberof communitiesandentities,including Boulder, Colorado,andtheDenverUrbanDrainageandFloodControlDistrict,havebeenimplementingnewsystemsforflashflood detectionandwarning.Thesystemsconsistof networks of low-cost, microprocessor-based radio telemetryrainandstream gauges linkedtoa community-based microcomputer.Thegauges transmitrainfall/streamflowdata to the

PAGE 122

Johnson111centralmicrocomputer,whichautomatically archives thedata.Ifthe datamagnitudes orratesof change exceed a predetermined threshold,analarmisenabled.TheBoulderCountyflashflood forecast systemisthemostcomprehensive ofanyalong the FrontRangeof Colorado.Thesystemconsistsof37raingaugesand12stream gauges,alllinkedbyradio telemetry to the BoulderCountyCommunicationsCenter (Johnson, 1984).Aninherentlimitationof the ground-based systemsisthe lack offorecastingcapabilitybeforerainfalloccurs.Thenetworkreportsrainfallandrunoff dataasitoccurs,whichlimitsthe available time fordownstreamflood warningstothe floodwavepropagation time.RadarEstimation of Rainfall Flash floods aremostoften theresultof intense thunderstorms producing largerainfallamounts(often20cmormore)in time periods of afewhours.Thearea encompassedbythe heaviestrainfallisusuallylessthan100to200sq.km.Forexample, the12September1977BrushCreekflash flood nearKansasCity, Missouri,where25peoplewerekilled,arosefroma drainage area of only 27.8 sq.km(Hales, 1978). Rainfall estimationcanbeaccomplished using datafroma raingaugenetwork, a radar and/or a meteorologicsatellite.Onlythe raingaugeisadirectsensor ofrainfallandassuchisperceived to provide the best estimatesataspecificlocation.However,asnoted above, a ground-based systemhaslimitedcapabilityfor sensing thespatialvariabilityofrainfallaswellasa limited response time for floodpredictionandwarning. Also, deploymentandmaintenance of a telemetered rain gauge network with the required resolution(1gaugeper 25-100 sq.km)canbeprohibitiveexcept in areas ofcriticalrecurring flooddamage.Radar, coupled with theraingaugenetwork,canprovideanimprovedbasis for sensing intenserainfallevents of the typewhichcauseflashfloods (Battan,1973;DoviakandZrnic, 1984). Asingle,high-resolution radariscapable of monitoringprecipitationeventsona routine basis for a 200,000 sq.kmarea withresolutionoflessthan 5 sq.kmanda temporal resolution of 5 minutes,ifdesired.Forcomparison,itwouldtake 8,000raingauges to cover thesamearea with thesameresolution.Accuracy of the radarreflectivityrainfallamountcorrelationscanbesignificantlyimprovedusing ground data forcalibration.Forexample,Wilsonand Brandes

PAGE 123

112HYDROLOGICMODELING(1979) estimatedthatinsomeinstances,use of 9round-basedraingauge data could reduce radarreflectivity-rainfallestimateerrorfrom100%to20%.Currently, withfewexceptions, radar data areavailableonly in photographicformformostNWSradarsandthesehavelimitedresolution.However,newgeneration Doppler radars provide higherresolution(1sq.km).andwith theNextGenerationRadarprogram (Wilk, 1979;NEXRAD,1984),thereispromise forhigh-quality,digitalradar coverage throughout the UnitedStatesin thecomingdecade. Watershed HydrologicResponseAvarietyof mathematicalmodelshavebeendevelopedandsuccessfullyutilizedtorepresentthe hydrologic response of a watershed torainfall.Thesemodelsrepresent the physical processes inherent in therainfall-runoffandstreamflow hydraulic systemsothattheamountanddepth of flowcanbepredicted.Examplesofsuchhydrologic modeling codes include the Soil Conservation ServiceTR-20models(SCS,1976,1984),INTERHYD(Johnson, 1984b,c),SWMM(Roesner,etal.,1981),andthe Generalized StreamflowModelof theNWS(Burnash, 1978). Alibraryof subroutinesextractedfrommanyof theabovecodeshasbeencompiledbyKoontz(1982). Definition ofrainfalldistributionover timeisconsideredoneof the major sources of uncertainty in watershed modelingforflood forecasting (Flueck,1981;Johnson, 1981c). This problemisparticularlysignificantin mountainousterrain.Althoughthereare several methods to performspatialinterpolationofrainfallamountsandestimatemeanarealrainfallbasedongaugemeasurements,nomethodaccuratelyrepresentsspatialevolutionofrainfallover a given time period (SinghandChowdhury,1986). Othererrorsources include the degree ofspatialresolutionusedto define the drainage system geometry,andfactorsrelatingto hydrologic response of the land surface(e.g.,topography,soiltypeandvegetation, antecedent soil moisture).TheNational OceanicandAtmospheric Administration's ExploratoryDevelopmentFacility(NOAA-EDF),located in Boulder, Colorado,hastheabilityto receiveandprocess avarietyofreal-timehydrologicdata.Amongthese are datafromtheCP-210cmexperimental Dopplerradar,whichprovideshigh-resolutionreflectivitydata not normallyavailablein operation norroutinelyavailablein real time.NOAA-EDFresearchactivitiesinclude radar sensing ofrainfall,andcalibrationusing ground basedraingauges (Lebel, 1984). Analysis algorithmshavebeenimplemented for

PAGE 124

Johnson113interfacingthe radarandraingaugedatasets,with promisingresultsobtained.TheBoulderCountyflashflood warning system provides higher density reporting of ground dataandthusanimprovedbasis for radarreflectivity-rainfallcalibration.Availabilityofmoreaccuraterainfalldatafromtheradar-raingaugenetworkscanbeexpected to providebetterdata for hydrologic models.Inaddition,there is aneedforincreased lead timesothatflooddamagereduction stepscanbetaken.Theabilitytocomputearealrainfallin real timeandtoforecastitsmovementcanincrease warning timeandreduce flooddamage.DataManagementandInteractiveComputerGraphicsInteractivecomputer graphics(ICG)techniqueshavebeenshowntobeasignificant aid for analysis of water resource systems (Loucks,etal.,1985;French,etal.,1979);including flood runoff (Johnson, 1981a), system operations (JohnsonandLoucks, 1978),andlanduseattributedatamanagement(Loucks,etal.,1983).lCGtechniquescanbeusedin a human-engineered environment to reduce the timeandeffortrequiredforinputandanalysis ofspatialdata bases, to guide analyses throughinteractivehuman-machinecommunication in nearreal-time,andto reviewresultsof analyses in areadilyunderstandable graphicform.Graphic displays of hazardous weatherphenomenacanalso provideanunderstandablemediumfor warning (Johnson, 1981b).Effortsdirectedto development ofinteractivedatamanagementandmodelinghavebeenmotivatedbythreefactors:1)tofacilitatedata inputandediting,2)to provideaneffectiveinterfacebetweenmodelsandmodelers,and3)toimprove tne comprehension of space-andtime-variable information. A primary goalhasbeen to developmodelsandcomputer-aided planning systemsthatare userfriendlyandeconomical.TheeconomyobjectivehasbeenfacilitatedbyimplementationonaPCbased workstationata cost oflessthan $10,000.AnICGworkstationequipped with high-resolution graphicsdisplayanddigitizingtabletpermits displayandmanipulation ofvideo-digitizedmapimagesin ways appropriateforhydrologic modeling.Useof a"menupage"formatandmodular software allows operator control of data manipulationsandanalyses.Thetablet cor beusedto"draw"watershed drainage systems into computermemory,whereuponthese dataformthe basis for subsequent computations of flood runoffandstreamflows.

PAGE 125

114HYDROLOGICMODELINGVideodigitizingtechnologyisusedtocapture color-codedpictorialdata bases,suchasmapsandmapoverlays. FlashFloodForecastingSystemResearchactivitiesaredirectedtolinkingthe componentsofaflashflood forecasting systemintoa unifiedICGdatamanagement,computational,andgraphics display system appropriate for systemtesting,sensitivityanalysisandeventualnear-real-timeapplication(Figure1).WatershedCharacteristicsFilesRainfall EstimationandPredictionWatershedHydrologicResponsePredictor FlashFloodForecast DisseminationStreamStage ReportingGaugesFIGUREI Flash floodforecastingsystem includes linkedmodulesforrainfallestimationandwatershedcharacteristics

PAGE 126

Johnson115rCGmapmanipulationisanessentialaspect of theflashflood forecasting system being developed. Watershed runoff parameter estimates, merging of geographic datasets(watersheds, raincells),andstorageandretrievalof data areallfunctions aidedbytherCGdatamanagementcapability.A recent version of theComputer-AidedPlanning(CAP)software (FrenchandTaylor,1986)isusedtoinitiatethe watershed data development process.Basemapsof topography, drainage systems,soils,land useandvegetation types are videodigitizedor enteredbytabletdigitizing.Theseinputmapscanthenbeoverlapped,edited,andoverlaid toformcompositemapswithallelements necessary tocomputeimportant watershedcharacteristicssuchasdrainage areas, stream reach lengths,andother "plan-view"attributes.Foranalysis purposes, aspecificcolor repre sentsanattribute(soiltype,rainfallintensity).rCGcapabilitieshavebeenextended to incorporate otherspatialdata,suchasradar-rainfallimages.Theradarimagecanbeaccessedandarchivedonthe local computer,andtheimagearraycanbeprocessed to obtainanestimate of therainfall. Linkage of radarrainfalldigitalimagery withanrCGwatershed datamanagementpackagehasbeenaccomplished.rCGtechniques areusedto overlay the radarreflectivityimageonto the watershedasa color transparency.Onlyreflectivityvaluesthatliewithin the delineated watershed are included, defining thecommonintersectingarea of stormandcatchment.Thegraphic overlay of thereflectivityimageisthen readfromthe screenandconverted to arainfallrate.Losses are subtractedandthetranslationtime to the basinoutletcomputed. Translationofprecipitationexcess into a runoff hydrograph involves a time area or isochronal approachfirstintroducedbyClark (1945). Clark developedanalgorithmwhichderives the instantaneousunithydrographfroma time-area diagram.Theinstantaneousunithydrographisthen routedbythe fundamental storage equation to account for storageeffectsin the watershed. Others(Chow,1964)havedescribed the technique.Forour purposes, the isochronal approachhasadvantages inthatitavoids theneedtoobtain a basin averagerainfallandisreadilyintegrated into the databasestructureestablishedfor the watershedandradarrainfalldatasets.

PAGE 127

116ConclusionsHYDROLOGICMODELINGUseof radarrainfallimageryfor flood runoff forecastingisfacilitatedusinginteractivecomputer graphics datamanagementsoftwareandhardware.TheICGsystem, implementedonalowcost desktop microcomputer, providescapabilityfor preprocessingmappeddata bases to define watershedcharacteristics,integrationof radarrainfallimagery,andcomputation of flood runoff. Ultimately, the software/hardware system could provideanimprovedbasisforforecasting flash floods. References Battan,L.J.1973RadarObservation of the Atmosphere. Chicago: UniversityofChicagoPress.Changnon,S.A.,Jr.,R.J.Schicht,andR.G.Semonin1983A PlanforResearchonFloodsandTheir Mitigation in the UnitedStates.IllinoisStateWaterSurvey, National Science Foundation Grant:NSF-PAG-81-17027.March.Chow,V.T.1964Handbookof Applied Hydrology.NewYork:McGraw-Hill. Clark,C.O.1945Storageandthe Unit Hydrograph.ASCETransactions, PaperNo.2261,Vol.110,pp.1419-1488. Doviak,R.J.andD.S.Zrnic1984DopplerRadarandWeatherObservations. Orlando,FL:AcademicPress. Flueck,J.A.1981"SomeStatisticalProblemsInherentInMeasuringPrecipitation,"Pages058-59inD.AtlasandO.W.Thiele,editors,PrecipitationMeasurementsfromSpace. Greenbelt,MD:NASAGoddardSpaceFlight Center. French,P.F.,etal.1979WaterResources PlanningUsingInteractiveComputerGraphics. Technical Completion Report to Office ofWaterResearchandTechnology, Cornell Department of Environmental EngineeringandProgramofComputerGraphics, (GrantNo.14-34-0001.6226). January. Hales,J.E.1978"TheKansasCity FlashFloodof12September 1977." Bulletin of theAmericanMeteorological Society59,pp.706-760.

PAGE 128

Johnson117Johnson,L.E.1981aAnInteractiveMethodfor DerivationandEvaluation of Reservoir OperatingPolicies.Doctoraldissertation,DepartmentofEnvironmentalEngineering, Cornell University.1981b"Strategiesfor Dissemination of EarlyWarningsonHazardousWeatherEventsUsingVideoImages." Paper presentedatIEEEInternational ConferenceonCommunications, Denver,CO,June.1984aSurvey ofReal-TimeHydrologicDataReporting Systems.DenverBoulder Region, Colorado. Report to the Prototype Regional ObservingandForecasting Service,NOAA,August.1984bINTERHYD--Interactive HydrologicandHydraulic SimulationModelsforUrbanDrainage Systems--Program DocumentationandUser'sManuals.Reporttothe City of Portland.1984cEast Side Interceptorand Fall BrookDrainageSystem-ComputerModelCalibrations.Report to the City of Portland,Maine,August. Johnson,L.E.,andO.P.Loucks1978"InteractiveMultiobjective PlanningUsingComputerGraphics,"ComputersandOperations Research 7 (#1-2).Koontz,C.1982Lebel,T.1985GeneralizedComputerProgram FloodEstimatesandRouting.KansasCityDistrict,KansasCity, Missouri:U.S.ArmyCorpsofEngineers. Real-Time Radar-RainfallReflectivitityCorrelationsUsingGroundBasedSensor Calibrations. Report toNOAA-PROFS,Boulder,CO.December.Loucks,D.P.,P.N.French,M.R.Taylor1982"Computer-Aided Resource Planning."ComputerGraphicsWorld(October),pp.28-32.Loucks,D.P.,M.R.Taylor,andP.N.French1985"InteractiveDataManagementfor Resource PlanningandAnalysis."WaterResources Research21(#2),pp131-142.NEXRADJointSystemProgramOffice.1984NextGenerationWeatherRadarAlgorithm Report.May.Roesner,L.A.,R.P.Shubinski,andJ.A.Aldrich1981StormWaterManagementModelUser'sManualVersionIII.Report to the University of Florida, Gainesville,FL.Singh,V.P.andP.K.Chowdhury1986"ComparingSomeMethodsof EstimatingMeanArealRainfall."WaterResources Bulletin22(#2),pp275-279.

PAGE 129

118HYDROLOGICMODELINGSoil Conservation Service(SCS)1976ComputerProgramfor Project Formulation Hydrology. Technical Report#20.Taylor,M.,P.French,andD.P.Loucks1983Digital ColorMappingandResource Planning. Orlando,FL:Pro ceedings of the National ConferenceonMicrocomputers in Civil Engineering.UrbanDrainageDistrict1984ColoradoUrbanHydroQraohProcedure.Computerprogramforurbandrainage analysis.Wilk,R.E.andJDOPStaff"Joint Doppler Operational Project, 1976-78."NOAATechnicalMemo.ERLNSSL-86,Norman,OK.Wilson,J.W.andE.A.Brandes1979"RadarMeasurementof Rainfall -ASummary."BulletinoftheAmericanMeteorological Society60,pp.1048-1058.

PAGE 130

OROGRAPHICPRECIPITATIONMODELFORECASTOFTHEBIGTHOMPSONFLOODDonnaF.TuckerE1marR.Reiter Department of Atmospheric Science ColoradoStateUniversity IntroductionTheBigThompsonfloodisaclassicexampleof the extremespatialvariationsinprecipitationamountswhichfrequently occur in areas withcomplextopography. Meteorological conditions leading toflashflood events in the western UnitedStateshavebeendescribedbyMaddoxeta1. (1980) but orographiceffectsare frequentlyanimportantcontributingfactor.Modelforecastingofsucheventsisdifficultandwouldalsobeexpensive in terms of computer time since a small grid spacingwouldbeneededto resolverelevantfeatures.Webelieve the expense of includingmorehorizontaldetailsin amodelusedincomplexterrainareas couldbereduced.Weassumethatasthe horizontalscaledecreases thedifferencesin thewindfieldfromthe largescaleflowwhichare important forcontrollingthedistributionofprecipitationare predominantlydueto surfaceelevationvariations.This controlisduenot only to upslope motions but also to the moisture convergencepatterns(BarkerandBanta, 1985;CaiandLi, 1983).Thusitispossible to solveforthesedifferencesusing a diaqnostic modelwith a grid spacingmuchsmaller thanthatofthe forecasting model.Byusing thewindsrevisedbythe diagnosticmodelin aprecipitationparameterizationitispossible to develop aprecipitationforecastthatisbothmoredetailedandmoreaccurate thanthatof the forecastingmodelalone.TheModelThemodelconsistsoftwoparts.Thefirstisa mesoscale forecastingmodelsimilarto theonedescribedbySheneta1. (1985). Thismodelhasa grid spacing of about96kmandsixverticallevels.Ituses the primitive equations insigmacoor dinatesandhasadomainconsistingofvirtuallytheentireUnitedStates.It

PAGE 131

120PRECIPITATIONMODELFig. 1 Abbreviatedmodelflowdiagram."A"stands for advectionandalpha symbolizesanyvariable.including a bulk parameterization of the planetary boundarylayerwith surface heatandmoisture fluxes.Ona smaller domain,whichincludes thestatesof ColoradoandUtahwithpartsofWyoming,Nebraska, Kansas,NewMexico,andArizona, a diagnosticmodelwith about a24kmgridspacingisalsoused. This diagnostic model, modifiedfromFosbergetal.(1976), finds only the orographically induced winds.Thewayinwhichthetwopartsofthismodelinteractcanbeseen in the flow diagramshownin Fig. 1.Ateach time step variablesfromthe forecastingmodelareinterpolatedonto the24kmgridandused asfirstguessfieldsforthe diagnostic model.Thediagnosticmodelthen uses thefirstguessfieldsto find theterraininduced divergenceandvorticityonthetwolowestmodellevels.Incomputing thesequantitiesituses africtionalterm basedonthestandard deviationofthe topographyandthestaticstability.Thewindsderivedfromtheterraininduced divergenceandvorticityfieldsareaddedto thefirstguesswindfieldto produce a horizontalvelocityfieldonthe24kmgrid.Anewverticalvelocityisthenfoundonthisgridwhichiscontinous with thenewhorizontalvelocityfield.Thesenewterrain-modifiedwindsare used to find both thegridscaleandsubgridscaleprecipitationonthe24kmgrid.Areal averagesofthesewinds(UTandV T ) are alsousedin the advectiveschemeofthe forecasting model. Application of theModelto theBigThompsonFloodTheBigThompsonfloodisa natural choicefora case studyforthismodelsince topography played akeyroleinitsproductionandsince theprecipitationvariationspresentonthatdaywereverygreat.Thesynopticandmesoscalefeaturesaccociated withthiseventhavebeendescribedbyCaracenaetal.(1978)andaresummarizedelsewhere in these proceedingssothey will notbediscussed here.

PAGE 132

TuckerandReiter121Fig. 2 (a)12hourmodelforecast700mbgeopotentialheightsandwindvalid00GMT1 August 1976. Heights are in decametersandcontours aredrawnfor every20m.Windvectors are normalized with the longest vector being 14.1 m/sec.Duetoitsfixed boundaries themodelcannot see the troughmovingonto the westcoast.Modelwindsin eastern Colorado are strongandfromthesoutheast.Thesewindswerevitalincreatingthe upslope conditionwhichformedtheBigThompsonstorm as wellasbringing moistairintothe area (Caracenaetal.,1978). Although the forecastingmodelobtains inputfromthe diagnosticmodelonthe smaller grid theforecastofgeopotential heightsislargelyunaffected.Thestreamlines of thewindsfoundbythe diagnosticmodelonthe24kmgridatthe lowestmodellevelat00GMT1 August1976areshownin Fig. 3. Thereisa strong convergencezonealong the FrontRange.Thewindsin eastern Coloradohavemoreofaneasterlycomponentthan thoseonthelargergrid.Thesewindsgeneratemoreupslope flow than thewindsonthe96kmgrid.Figure 4 contains the24hourtotalforecastprecipitationandthe actual precipitationwhichfellduringthatperiod.Almostalltheprecipitationin the Estes Park areawasforecasttofallbetweenaGMTandsixGMTonAugust 1whichwasapprox imately thesametimeatwhichthe actual stormpersisted.Although therewereThelargescalemodelforecastof geopotential heightandwindfieldsat700mbtogether with observedfieldswith analysis takenfromMaddoxetal.(1977)for00GMTAugust1,1976, areshownin Fig. 2. Forecast heightfieldsatthislevel are generally toolowin the northernandcentralplains.Since theforecastmodelhasfixed boundariesonemightinitiallythinkthatthe problemisaresultofthiscondition. This explanation does not appear tobevalid since with the Limited FineMeshmodelforecast(notshown)ofthe National Meteorological Center thesameerrorsoccurred. Sincethisproblem does not appearat300mb(notshown)itcouldbetheresultofaninterpolationerrorfromthesigmasurfaces to the pressure surfacesratherthananerrorin themodelforecastitself.

PAGE 133

122Fig. 2 (b)700mbanalysisfor00GMT1August1976. Height contours aredrawnevery20mandisotherms areattwodegree Celsiusintervals.Regionswherethe dewpointislessthansixdegrees Celsius are shaded[FromMaddoxetal.,1977]. Fig. 3 Streamlines ofwindsfoundbythe diagnosticmodelatthe lowestmodellevel validat00GMT1 August 1976.PRECIPITATIONMODELreportsofupto12inchesofrainin theBigThompsonCanyonthemagnitude of theprecipitationforecastisprobablySomewhatexcessive.Sensitivitystudieswith themodelindicatethatthiserrorismostlikelycausedbythe smallnumberofverticallevelsin themodelandbyinitialverticalinterpolationerrors.Thepredictedlocationof this maximum,however,isvery good.Eventhoughtherewerefewofficialreportsofrainfallin southernWyomingtherewerereportsofflashflooding in the Wheatlandarea.Thusa considerableamountofrainappears tohavefallentherealso.Thereisalsogoodqualitativeagreementbetweenthe observationsandtheforecastin Utah,centralWyoming,andtheeasternplainsofColorado. Aprecipitationforecastdonebytheforecastingmodelalone (with out the enhanced topography,designatedFO)onthe96kmgridcanbeseen in Fig. 5.Fromaqualitativecomparisonofthetwoforecastsitcanbeseenthattheforecastingmodelalone gives amuchpoorerrepresentationoftheamountofrainfallin theColorado-Utah-Wyomingarea than themodelwith the inputoftheterraininducedwindsonthe nestedgrid.Theimprovementin the pre-

PAGE 134

TuckerandReiter123 r." cipitationforecastiscausedbyadding the orographica11y inducedwindsOnthe24 km grid,eventhoughthe geopotentia1 height forecastsofthetwomodelsonthe96 km 9rid are quite similar. Fig. 4 (a)24hourmodelforecast cumulative precipitation inmmonthe nested grid ending12GMT1August1976.Contours areat5,35, 65, 95, 125,155, 185,and21511111 It .It: Q . .00:0, a. r..,.r-:: . ;---.::.,,-.-:.,...--.....1 '1 .'1'.I.' t .oo.,d.. . t.' ",: 4 f.:. ":'1.: :, 11 :.'0' a:. .. ..tll.. ',.1.1'., tt:, II.'.:., ....... :. l:a .. i .. 1I:t':'10" r. ..... :..... .:. 00-::.'C 1.1 It:.I:O.I'.J"'.\r., r.,,&:....,....... '.1...4,1:.0.8....I.:, Dr:."fl. .0 :. ,:, ...:0.1.1,:Fig. 4 (b)Observedprecipitation in11111for the24hourperiod ending12 GMT 1August1976.

PAGE 135

124PRECIPITATIONMODELFig. 524hourcumulativeprecipitationforecastmadebytheforecastmodelalone(FO)(Sheneta1.,1985)for the period ending12GMT1 August 1976. Contours aredrawnfrom1mmto46mmatanintervalof 5mm.DiscussionandConclusionsInaddition to the case presented here, threeothercaseshavebeenusedtodate totestthismodel.Theyare theCheyennefloodonAugust1,1985, a caseonJuly 28,1976whichhadonly moderateprecipitation,andthe SurryRidgecase of July 19,1985whichwasaccompaniedbyheavyrainsin theDenverandColorado Springsareas.Toverifytheprecipitationforecastsproducedbythismodelmultivariaterandomized block permutation procedures(MRBP)developedbyMielke (1984,1986)wereused tocomparetheforecastswithallavailableobservations.Theforecastsweresignificantatthe 0.05 levelwhichisaslowas couldbeexpected withthissmall a sample.TheprecipitationforecastsproducedbytheFOmodelwerenotsignificant.However,itispossible to say with a confidence levelonthe order of 107thatthe geopotential heightforecastsoftheFOmodelandthe completemodeldid notdiffersignificantlyfromthe observedfieldsorfromeach other.Theseresultsofferhopethatitmaybepossible to improveprecipitationforecastsbymesoscalemodelsin areas withcomplextopography through abettertreatment of the smallscaletopography. AnthesandHaagenson(1983) found

PAGE 136

125TuckerandReiterprecipitationforecastsin mesoscalemodelstobebetterwith amoredetailedtopography than with asmoothedone.Butresultshereindicatethatinatleastsomecasesitmaynotbenecessary toexplicitlydecrease the gridsizeof the forecastingmodelto resolve the features important forattainingthisimprove ment.Allthe processes represented in the forecastingmodelare not necessary to produceanimprovedforecastusinga nested grid because thewindscontrollingthe smallscaleconvectiveprecipitationdistributionare primarily forcedbythe topography insituationsofwhichthe casestudiesarerepresentative.Finally,the addition of these topographically inducedwindsto themodelresultedinsignificantchangesoftheprecipitation-forecastbut in only small changesofthelargescalegeopotential heightforecastindicatingthatthekeytopredictingprecipitationin regions withcomplexterrainmaybeabetterrepresentationof the orographiceffectsratherthananimprovementin the simulation of the geopotential heights.AcknowledgementsTheresearch inthispaperwassupportedbyNational Science Foundation GrantNo.ATM83-13270.Weappreciate theworkof Laneigh Brumit in preparingthismanuscript.

PAGE 137

126ReferencesPRECIPITATIONMODELAnthes, RichardA.andPhilipHaagenson1983"Acomparative numerical simulation of the Sichuan floodingcatastrophe(11-15 July 1981)."Pages519-524 in Proc.FirstSino-AmericanWorkshoponMountainMeteorology,Beijing,China:Amer.Meteor. Soc. Barker, CrystalL.andRobertM.Banta1985"Preferred regions of thunderstorminitiationover the Colorado Rockies."Pages17-20 inPreprints,14thConf.onSevereLocalStorms, Indianapolis,IN:Amer.Meteor. Soc. Cai,ZeyiandJishunLi1983"Someobservational evidence of the influenceoftopographyonsevere rainstorms in China."Pages457-472 in ProcFirstSino-AmericanWorkshoponMountainMeteorology,Beijing,China:Amer.Meteor. Soc. Caracena, Fernando, RobertMaddox,L.RayHoxit,andCharlesF.Chappell1979"Mesoana1ysis of theBigThompsonstorm."Mon.WeaRev., 107: 1-17. Fosberg,MichaelA., WilliamE.Marlatt,andLawrenceKrupnak1976"Estimatingair-flowpatternsovercomplexterrain.U.S.For.ServoRockyMt.For.RangeExp.Stn.Res.Pap.RM-162:16.Maddox,Robert A., Fernando Caracena,LeeR.Hoxit,andCharlesF.Chappell1977"Meteorological aspects of theBigThompsonflashfloodof31July 1976."NOAATech. ReportERL388-APCL41:83.Maddox,Robert A.,FayeCanova,andL.RayHoxit1980"Meteorologicalcharacteristicsofflashflood events over the western UnitedStates."Mon.Wea.Rev.108: 1866-1877Mie1ke,P.W.1984"Meteorologicalapplicationsof permutation techniques basedondistancefunctions."InP.R. KrishnaiahandP.K.Sen, Eds.HandbookofStatistics,Vol. 4 Elsevier Science Publishers.1986"Non-metricstatisticalanalysis:somemetricalternatives."J.Statist.P1ann.Inference 13: 337-387. Shen, Rujin,E1marR.Reiter,andJamesF.Bresch1985"Asimplified hydrodynamic mesoscalemodelsuitableforuser over plateau regions." Archiv.Met.Geophys.Biok1im.,A34:3-4.

PAGE 138

OPERATIONAL,SATELLITE-DERIVEDPRECIPITATIONESTIMATESANDFORECASTSRoderick ScofieldNOAA/NESDISPrecipitationinformationisa primary requirement of hydrologistsandagri-culturalistsaround the world.Alsoof utmost importanceistheneedtomakeestimates of areas ofheavyprecipitationpriorto issuance offlashflood or winter storm warningsandspecial weather statements. Hydrologists, meteorologists,andriverfore-castersuseprecipitationestimatesasanaid intheirevaluation or prediction of floodpotential.Visible(VIS)andgeostationaryinfrared(IR)satelliteimagery arecurrentlybeing usedoperationallyforanalyzingandforecastingheavyprecipitationevents.Satellite-derivedprecipitationestimatesand3-hourprecipitationtrends for convec-tivesystems (ScofieldandOliver, 1977;Scofield,1984;SpaydandScofield,1984a),extratropicalcyclones (ScofieldandSpayd, 1984),andtropicalcyclones(SpaydandScofield,1984b)arecomputedontheNESDISInteractiveFlash Flood Analyzer(IFFA)andtransmitted viaAFOStoNWSForeccastoffices,NWSoffices,andRiver Forecast Centers.TheNational Hurricane Center uses amethoddevelopedbyJarvinenandGriffith(1981) forforecastingtropicalcyclonerainfallatlandfall.MilestonesandFuture TechniquesTheoperationalNESDISConvectiveStormTechnique gives half-hourly or hourlyrainfallestimatesforconvective systemsbyusing GOES IRandhighresolutionVISima-ges.Thetechniqueisdesignedfordeepconvective systemsthatoccur intropicalairmasses with high tropopausesanditisapplied usingIRimages(Fig.1)displayed according todigitalehancement curve(Mbcurve) designed to help estimate convective stormintensity.Theconvective system in Fig. 1isa mesoscale convectivecomplexwhichproducedflashfloods overKansasCity,MO.MCC'sare easy toidentifyin the

PAGE 139

128ESTIMATESANDFORECASTSsatelliteimagery;satelliteprecipitationestimatesforthese types of systems are normallyquiteaccurate. Estimates of convectiverainfallarecommputedbycomparing changes in cloudcharacterbetweentwoconsecutive images.Thetechniqueisdividedintothreemainparts:(a)Theactiveportion of the convective systemisidentified.Thisisthe area of strong updraftsandcoincides with theheavyrainportion of the cumulonimbus.Forthunderstorm systemsembeddedin a moderate to strongverticalwindshear environment, the heaviestrainfallmostoftenfallsalong theupwindedgeof the anvil (between AandA'in Fig.1).Theinactivedownwindportion of the anvilisbetween BandB'(Fig.1).Forthunderstorm systemsembeddedin aweakverticalwindshear environment, the heaviestrainfallmostoftenfallsnear the center of theanvil.(b)Thecomputation of thehalf-hourlyconvectiverainfallestimateiscomputedfortheactiveportion usingfivemeteorologicalfactors:Factor 1: Cloud-top temperatureandcloudgrowthORdivergencealoft.Factor2:Overshooting top; inVISimagesovershooting tops arequitebrightandtextured.Factor3:ThunderstormclusterORconvective cloudlinemerger. Factor4:Saturated environment; thesaturatedenvironmentfactorrefersto those thunderstormsthatarelong-lived,cover largeareas,andarestationary.Thesestorms possessstrong,relativelysteady-stateupdraftsandoutflows, a large areasaturatedto greatheights,anda lack of dryairentrainment. Factor5:Moisturecorrection;a mositurecorrectionfactorhasbeendeve lopedforadjusting estimateswhentheairisunusually dry orquitemoist. (c)Thesummationof thefactorsandmultiplicationbythe moisturecorrectionfactor.Amoredetailedexplanation of the convective techniqueispresented in Scofield (1984).

PAGE 140

Scofield129Asmentioned above, the convective technique using theIRenhancement curve(Mb)wasdesignedforestimatingrainfallfromdeepconvective systems with a hightropicaltropopause.However,thestrengthof the convectionisoften best estimatedbyacomparison of the temperature of the convective tops with the computationsfromthe soun dings(calledthe equilibriumlevel).Onthese occasions, the anvil spreads outatthestablelayeratthe top of the area offreeconvection, notatthe tropopause.Whenthisoccurs, temperatureswarmerthan-62Coccur in theanvil.TheMbcurvedoesnotshowthedetailsatthese temperaturesclearly.TheConvectivePrecipitationEstimation Techniquehasbeenmodifiedsothatthe temperature of the convectioncomputedfroma soundingiscomparedwith the observed cloud-top temperature. Thiscomputedtemperatureisthe best measure of the expected anvil temperatureandshouldbeusedforexamining the anvilgrowthrates.Cloudtop temperatures equal to or colder than thecomputedtemperaturewouldindicateheavierrainfallratesthanwarmerones.Asaresultof the above, a modification to the tech niqueforwarmtops hasbeendeveloped (seeScofield,1984).Anexampleof asubtlewarmtop devastatingflashfloodisshown(at5)in Fig. 2. This flood occurred in Eastern Kentuckyandproducedmuchpropertydamage;several peoplewerealsokilled.Warmtopflashflood producing thunderstormssuchastheonein Fig. 2 are often hard toidentifyin thesatelliteimagery.TheIFFA,whichbecameoperational inAugust1983, represents atransferof tech nologyandtechniquesfromNOAAresearchfacilitiesto operationalforecastersandmeteorologists.Theoverall philosophy ofIFFAisto convertdigitalsatellitedata,whicharelowin informationandhigh involumeto asatelliteproductwhichishigh in informationandlowinvolume.Thegoal ofIFFA;stoimprovethe accuracyandtimeliness ofsatelliteprecipitationestimates.Thesatellitemeteorologistinteractswith the computer, each performing taskswhichthey are bestsuitedfor.Themeteorologists

PAGE 141

130ESTIMATESANDFORECASTSprovide theintelligenceandanalysisfunctions while the computer provides the speedandaccuracy of computingprecipitationproducts in the requiredmapformats.GOESdigitaldata are received inreal-timethrough the DigitalInterfaceElectronics,processed with aHarris/6minicomputer,andstoredontwo80megabyte removabledisks.TheIFFAoperational configurationconsistsoftwocomplete, redun dant systems.Incase of hardwarefailure,the removable diskscanbetransferredto the back-up systemandoperationalworkresumed.TheIFFAsystem also includes operatorconsoles,1600BPIg-track tapedrives,a card reader,lineprinterandtwoapplicationsterminals.EachterminalconsistsofanIntel8080commandprocessor connected to a color monitorandanalpha-numericalCRTscreen with a keyboard. Ajoystickanda datatabletareusedto position the cursoronthe screen toviewenlarged areasanddrawisohyets. A Versatec hardcopyoutput deviceisusedto produce a permanentimageof therainfallestimates.Themeteorologistcanannotate the countynamesandthe posi tion ofmaximumandminimumrainfallvalues in tenths ofaninch.Theestimates are disseminated in realtime using theAFOSPIL-header"SPENES"andare generallyavailableto theNWS20to30minutesafterthelatestimagetime used. These messages provide valuable guidance forNWSForecast Offices responsibleforflash flood watchesandwarnings.Asapilotexperiment,selectiverainfallestimates inTexasaredigitizedatpredetermined grid pointsandenteredintotheIBM-360NOAAcomputer.TheWestGulf River Forecast Centerhasbeenevaluatingandusing these estimate experimentally the pasttwoyears.Theverificationresultsshowthe averageerrorof therainfallestimatesfora stormtotalprecipitationeventisaboutthirtypercent.Theabsoluteandaverageerrorboth increaseasthe magnitude of the eventincreases.Forrelativelysmall events (3.9 inches orless)thereisa tendency to overestimate the eventandasthe magnitude of the event increases thereisadistincttrend of underestimating the

PAGE 142

Scofield131event. Operational users ofthisproduct should feel very confidentthatifarainfallestimate of four inches ormoreisreceived, thereisanexcellentprobabilitythatatleastfour inches willbeobserved. Future improvements to the techniquehavenotbeenexhaustedandwillmorethanlikelybecomearealitywhenGOESVASdatabecomesavailable.VASisanacronymforVISandIRspin scan radiometer Atmospheric Sounder.Theinclusion ofVASdata will allow for abettermoisture correctionandalowlevel moisture inflowfactor.Inaddition, a short range forecasting algorithm (seeMoses,1981)whichusesGOESVASdata topredictthunderstorm trendsandprecipitationisexpected tobedeveloped.AcknowledgmentsTheauthorwouldliketo thank TinaCashmanfor typing the manuscript,JohnShadid fordraftingthefigures,andGeneDunlapfor reproduction of thesatelliteimagery. ReferencesBarrett,E.C.1970"TheEstimation ofMonthlyRainfallfromSatelliteData."MonthlyWeatherReview,98, 322-327. Clark,D.and1984Fleming, E.,1984R.Borneman"SatellitePrecipitationEstimatesProgramof the Synoptic Analysis Branch."Pages392-393 in the Proceedings of the 10th ConferenceonWeather ForecastingandAnalysis, ClearwaterBeach,FL,AmericanMeteorological Society, Boston,MA.L.Spayd,Jr.andR.A.Scofield"Characteristicsof EasternRegionConvective FlashFloodEvents inGOESImagery."Pages409-417in the Proceedings of the 10th ConferenceonWeather ForecastingandAnalysis, ClearwaterBeach,FL,AmericanMeteorological Society, Boston,MA.Fleming,E.1986andL.Spayd,Jr.CharacteristicsofWesternRegionFlashFloodEvents inGOESImageryandConventional Data.NOAATechnicalMemorandumNESDIS13, Washington,DC:Department ofCommerce.

PAGE 143

132Griffith,C.1976Jarvinen,B.1984ESTIMATESANDFORECASTSG., W. L.Woodley,D. W. Martin,etal.Rainfall EstimationfromGeosynchromousSatelliteImagery During Daylight Hours.NOAATechnical ReportERL356-WMP07,Washington,DC:Department ofCommerce.R.andC.G.Griffith"Forecasting RainfallonTropical CyclonesUsingDigitized InfraredSatelliteData." UnpublishedNDAANHC,ERLTechnical Paper,Miami,FL:Department ofCommerce.Moses,J.F.1981"Convective Cloud-Tracking TechniquesforEstimatingPrecipitationfromGeostationary Imagery."Pages151-158 in the Proceedings of the Fourth ConferenceonHydrometeorology,Reno,NV,AmericanMeteorological Society, Boston,MA.Scofield,R.A.andV.J.Oliver1977ASchemefor Estimating Convective RainfallfromSatelliteImagery.NOAATechnicalMemorandumNESS86, Washington,DC:Department ofCommerce.Spayd,L.E.,1983Scofield,R.1980Scofield,R.1980Scofield,R.1981Scofield,R.1984Scofield,R.1984A.andV.J.Oliver"SomeImprovementsto theScofeild/OliverTechnique."Pages115-122 in the Proceedings of theSecondConferenceonFlash Floods,Atlanta,GA,AmericanMeteorological Society, Boston,MA.A.,V.J.Oliver,andL.E.Spayd,Jr."Estimating RainfallfromThunderstorms with Warm Topsinthe Infrared Imagery."Pages85-92 in the Proceedings of the Eighth Conferenceon Weather ForecastingandAnalysis, Denver,CO,AmerlcanMeteorological Society, Boston,MA.A."Satellite-DerivedRainfall Estimates for the Brady'sBend,Pennsylvania, Flash Flood."Pages188-193 in the Proceedings of the Fourth ConferenceonHydrometeorology,Reno,NV,AmericanMeteorologlcal Society, Boston,MA.A."TheNESDISOperational ConvectivePrecipitationEstimation Technique." Pages 171-180 in the Proceedings of the lOth Conferenceon Weather ForecastingandAnalysis, Clearwater Beach,FL,AmericanMeteorological Society, Boston,MA.A.andL.E.Spayd,Jr.A TechniquethatUsesSatellite,RadarandConventionalDataforAnalyzingPreclpitationfromExtratropical Cyclones.NOAATechnicalMemorandumNESDIS8, Washington,DC:Department ofCommerce.Jr.andR.A.Scofield "Operationally Detecting Flash Flood Producing Thunderstorms Which HaveSubtleHeavyRainfall Signatures inGOESImagery."Pages190-197 in the Proceedings of theFifthConferenceonHydrometeorology, Tulsa,OK,AmericanMeteorological Society, Boston,MA.

PAGE 144

Scofield Spayd,L.E.,1984aSpayd,L.E.,1984b133Jr.andR.A.Scofield"AnExperimentalSatellite-DerivedHeavyConvective Rainfall Short-Range Forecasting Technique."Pages400-408 in the Proceedings of the lOth ConferenceonWeatherForecastingandAnalysis, ClearwaterBeach,FL,AmericanMeteorological Society, Boston,MA.Jr.andR.A.Scofield A Tropical CyclonePrecipitationEstimation TechniqueUsingGeostationarySatelliteData.NOAATechnicalMemorandumNESDIS5, Washington,DC:Department ofCommerce.Woodley,W.L.,B.Sancho,andA.H,Miller1972Rainfall EstimationfromSatellitePhotographs.NOAATechnicalMemorandumERLOD-ll, Washington,DC:Department ofCommerce.

PAGE 145

Fig. 1Enhancedinfraredimagery(Mbcurve),0900GMT,AU9ust13, 1982. Fig. 2Enhancedinfraredimagery(Mbcurve),0930GMT,July15, 1979.

PAGE 146

TABLE1MILESTONESINOPERATIONALSATELLITE-DERIVEDHEAVYPRECIPITATIONESTIMATIONANDFORECASTINGTECHNIQUESDate5-10YEARSBEFOREBIGTHOMPSON(BBT)I31JULY1976APRIL1977SUHMER1978HARCH1980 SUHMER 1980JUNE1980OCTOBER1981AUGUST1963JULY1984NOVEM8ER19841966 1987 12-14YEARSAFTERBIGTHOMPSON(ABT)15-20YEARSAFTER81GTHOMPSONIA8T)aFIRSTPOLARORBITERPRECIPITATIONESTIMATIONTECHNIQUEWASOEVELOPED(BARRETT,1970)aFIRSTGOESPRECIPITATIONESTIMATIONTECHNIQUE WAS OEVELOPEOIWOODLY/GRIFFITH,1972, 1976)BIGTHOMPSONflASHflOODIATECHNIQUEFORESTIMATINGCONVECTIVERAINFALLFROMGOESIMAGERYWASDEVELOPED(SCOFIELO/OLIVER,1977)IMPLEMENTEDFIRSTOPERATIONAL/MANUALPRECIPITATIONESTIMATIONTECHNIQUE[SYNOPTICANALYSISBRANCH(SABI,NESDISlIMPROVEMENTSTOTHEOPERATIONALTECHNIQUE WERE DEVELOPED(SCOFIELO/OLIVER,1960)NATIONALHURRICANECENTERIMPLEMENTSTECHNIQUEFORFORECASTINGRAINFALLFROMTROPICALCYCLONES(JARVINEN/GRIFFITH,1981)PROBLEMSINESTIMATINGRAINFALLFROMWARMTOPPEDTHUNDERSTORMSINTHEINFRAREDIMAGERY WERE 10ENTlFIEO,OOCUMENTEO,ANDPUBLISHEO(SCOFIELO/OLIVER/SPAYO,1960)ATECHNIQUETOESTIMATERAINFAllFROMWARMTOrPEDTHUNDERSTORMSWASDEVELOPED(SCOFIELD/SPAYO,1961, 1963)IMPLEMENTEDTHEINTERACTIVEFLASHFLOODANALYZER(lFFA)FORESTIMATINGRAINFALL(SA8,NESDIS,CLARKAND6ORNEMAN,1984) ATECHNIQUEFORESTIMATINGANOFORECASTINGRAINFALLFROMTROPICALCYCLONESWASOEVELOPEDANOIMPLEMENTED(SPAYO/SCOFIELO,1984) ATECHNIQUEFORESTIMATINGANOFORECASTINGPRECIPITATIONFROMEXTRATROPICALCYCLONESWASDEVELOPEOANDIMPLEMENTED(SCOFIELO/SPAYD,1984)DOCUMENTEDSATELLITECHARACTERISTICSOFFLASHFLOODSINEASTERNANDWESTERNREGIONS(SPAYD/FLEMING,1984, 1986)WILLOEVELOP:1.ARAINGUSHFACTOR2.A3HOURCONVECTIVEPRECIPITATIONESTIMATIONOUTLOOKTECHNIQUE3.ACONVECTIVEFLASHFLooOPOTENTIALINDEX4.ANAUTOMATEDPRECIPITATIONESTIMATIONTECHNIQUE1.USEGOESVASFORIMPROVINGPRECIPITATIONESTIMATESBYDEVELOPINGALOWLEVELMOISTUREINFLOWFACTOR,ASPEEOOFCONVECTIVESTORMFACTORANDA8ETTERMOISTURECORRECTIONFACTOR2.COM81NEPASSIVEMICROWAVEWITHVISANDIRMETHODOLOGIESFORIMPROVINGPRECIPITATIONESTIMATES3.CONTINUETODEVELOPANDIMPROVEFLASHFLOODINDEX4.CONTINUETODEVELOPANDIHPROVETHEAUTOMATEDPRECIPITATIONESTIMATIONANDTRACKINGTECHNIQUEINTEGRATETOGETHERINFORMATIONFROMGOES-NEXT,NEXRAO,VERTICALPROFILERS,RAINGAUGES(INCLUDINGHIGHRESOLUTIONOPERATIONALNETWORKS).ETC.FORTHEDEVELOPMENTOFTHEBESTPRECIPITATIONANALYSISANDFORECASTINGTECHNIQUES.

PAGE 147

TECHNOLOGICALDEVELOPMENTSINFLASHFLOODFORECASTINGWITHINTHENATIONALWEATHERSERVICEEdwardJ.VanBlargan Hydrologic Research Laboratory National Weather Service,NOAAIntroductionAverageannual flood losses increase 5 per year primarily becauseofhumanencroachmentonfloodplains.These lossesmaybepartiallyreducedbyforecastsaloneifthe lead timeandaccuracy arereliable(Oay, 1970).TheNationalWeatherService(NWS)hasbeenmandatedbythe OrganicActof1B90toprovide floodforecastsnationwide, includingforecastsofflashfloodswhichare loosely defined as rapidly occurring floodsthatcrestwithin12hours of the causativerainfall(Barrett,1983).Toaccomplishthismission, the NWS has developedandisinvestigatingvarious techniques forflash-floodforecasting.Thepurpose ofthispaperistodescribeexistingandfuturecapabilitiesforflash-floodforecastingwithin theNWS.Anevolution of techniques willbeshownin sections dealing withtraditional,recent,andfuture methods.Themosteffectiveforecastingcombinesmeteorologicalandhydrological techniques (Hall,1981)withcomponentsforrainfallforecasting,arealrainfallestimation,andhydrologicmodeling. Discussion will focusonthesecomponentsandassociatedcharacteristicsoftimeliness,accuracy,andinformation content oftheforecast.TraditionalMethodsFlash-floodforecastingproceduresasdescribedbyMogiletal.(1978) remainedrelativelyunchanged formanyyears.Thesetraditionalmethodsaredescribed intwogroups,NWSwarningsandlocal flood warning systems. Unfortunately,thereislittlearchived informationthatcanbeusedtoquantitativelyassess the performance of these procedures, the magnitude of lossesactuallyreducedbyforecasts,or theamountofimprovementgained withnewprocedures.

PAGE 148

VanBlargen137NWSWarningsTheNWSgenerally produces area-wide warningsthatare issuedwhenrainfallexceeds the "guidancevalue."These warningsindicategeneral geographic areas(e.g.,a county)wherefloodingislikelytooccur without designatingthemagnitude of flooding expected or thespecificstreamsaffected.Occasionally,stageforecastsforspecificstreams are issued using "headwatertables."Theguidance valueandheadwatertablesare predetermined (i.e.,calculatedpriortoanyevent)atRiver Forecast Centers (RFC's), but are usedatWeather Service Forecast Offices(WSFO's)because therainfalldataiscollectedthereandsignificantdelays occur beforeRFC'sreceivethedata.Therainfallinputismanuallyassimilatedusing avarietyof sources including automatedandtelephonedgagereports,manuallydigitizedradar(MDR),satelliteestimates,andquantitativeprecipitationforecasts(QPF)fromthe Notional Meteorological Center(NMC).Theforecastersubjectivelyestimates arealrainfallamountsfor areasaffectedbysevere weather. Guidance valuesindicatetheamountofrainfallrequiredtoinitiateflashfloodingforspecificcountiesanddurations (see Table1).Thedetermination of guidance valuesissomewhatsubjectiveandvariesamongRFC's. Typically,anAntecedentPrecipitationIndex(API)relationship(Linsleyetal.,1958)isusedtodetermine therainfallrequiredtoyieldsome"critical"runoff value(e.g.,1 inch)fora given duration(e.g.,3 hours),whichisthen convertedtootherdurations with "conversionfactors."Thecriticalrunoff valueandconversionfactorsaresubjectivelychosen basedonexperience of theRFC.Guidance values are recomputeddailytoreflectchangingsoilmoisture conditionsandrepresentanaverage indexforanarea withnoreflectionofvariationsofsoilmoisture or hydrologic responseonindividualbasins.Headwatertablesare compiledforindividual basinsandcontain predetermined stageforecastsforvarious combinationsofrainfallamount,rainfallduration,andguidance value (see Table2).Thetablesaretypicallycompiled usinganAPIrelationship,ratingcurve,andunithydrographwhichmaybesyntheticallyderived (Sheridan, 1953).Theguidance valueandheadwatertablesweredesignedtobeeasymanuallookupmethodsappropriatefor use withthesparsegageddataandlimitedcomputer resourcesattheWSFO.Theaccuracycanberelativelysufficient,especiallyif

PAGE 149

AverageRainfall (i nches)NeededtoBeginFloodingStateandCounty3-hour 12-hour 24-hour Kentucky: Floyd 1.8 3.0 3.5Martin 2.1 3.4 3.8 Pike 1.5 2.6 3.1 Virginia:Buchanan2.2 3.4 3.9Dickenson 2.2 3.5 3.9WestVirginia:Logan1.4 2.5 2.9Mingo1.4 2.4 2.8 Table 1.Exampleofflash-floodguidance values Guidance InchesofRainin 3HoursValue1.0 2.0 3.0 4.0 5.0Forecast ed Stages(feet)1.0 12.6 15.317.2 18.5 19.4 2.0 9.9 12.6 15.217.118.5 3.0 3.5 10.1 12.5 14.6 16.6 4.0 3.5 3.5 10.1 12.6 15.1 5.0 3.53.53.5 10.7 12.8Table 2.Exampleof a headwatertable

PAGE 150

VanBlargen139therainfallisgagedandoccurs in asingleevent conformingtooneof the predetermineddurations.However,four general problems hindertheseproceduresandthus reducethecredibilityofNWSwarningsamongsomeusers (Wright, 1985).First,theproceduresaremanualandrequiresubjectivedecisionswhichcancreatetimedelays.Second,forecastaccuracyisreduced becausetheQPF,MDR,andsatelliteestimatesarenotconsistentlyreliableforsmall areasandthegagedobservationsaresparseinmanyareas.Third, using predeterminedrainfallsequencesisnot asflexibleas using a hydrologic model, which can analyzeactualrainfallsequences as they occurincludingmultiplerainfallbursts.Finally,because oflimiteddataandtime,general area-wide warningsaretypicallyissued.These warnings lackspecificinformation needed forpublicactionsuchasthe magnitudeandlocationof flooding(CarterandClark,1983). Local FloodWarningSystemsTheNWScooperates with communitiestoestablishlocalflood warning systemsthatallowthecommunitytomonitorrainfallandmakeforecasts.Twotypes of systemshavetraditionallybeenestablished,self-helpandalarm-gage(Barrett,1983).Theself-helparemanualsystems comprised ofvolunteerrainfallobservers,a headwatertableprovidedbyNWS,acommunityflash-floodcoordinator,andanemergency responseplan.Someofthekeyfeaturesoftheself-helpsystemsaregoodspatialcoverage ofrainfallgages,site-specificstageforecasts,andlowcost.However,timelinessisstilllimitedduetothemanualnatureandthelack offorecastrainfallinformation.Thealarm-gageconsistsofanupstreamrivergagethattriggersacommunityalarmwhentheriverstageexceedspresetthresholdlevels.Thealarm conceptissimpleandquiteaccuratesinceitdoes notrelyonrainfallmeasurementandrunoff conversion.However,togainsufficientlead timethelevelsmustbesetfairlylow,andthereisnoinformationtoindicateiftheriverwillcontinuetoincrease.Somecommunities combineanalarm gage with aself-helpsystemtohelp overcomethisproblem. RecentMethodsSeveral systemshaveevolved overthelasttenyearsthataddresssomedeficienciesof thetraditionalmethods. These systems(ALERT,IFLOWS,ADVIS)are

PAGE 151

140FLASHFLOODFORECASTINGcomputerized local flood warningsystemsthatuse automatedevent-reportingrain gages.Thesehavebeenimplementedoperationally,but only inspecificlocations.ALERTTheALERTsystem(AutomatedLocalEvaluation inRealTime)wasdevelopedattheNWSCalifornia-NevadaRFCandconsistsof automated,event-reportingriverandrain gages (BurnashandBartfeld,1980).Dataare storedandanalyzed with the Sacramentomodeltooutput a streamflow hydrograph (Burnashetal.,1973).ALERTalso analyzes the impact of variousfuturerainfallamountsbut does notactuallymakerainfallforecasts.Itwasdesignedtobeownedandusedbya community. Derivatives of theoriginalsystem arenowmarketedbytheprivatesector.ALERTwasthoughtfully designedtoovercomesomeof the majorobstaclesofflash-floodforecastingandwith theforesighttotake advantage of microcomputer technology.Itminimizesmuchofthetime delay inherent in thetraditionalmethodsbecauseitisautomated, basedoneventreports,andlocallyoperated withnoreal-timeinteractionwithNWSoffices.Also,itprovidesgoodspatialcoverage ofrainfallgagesandutilizesaflexiblehydrologicmodeltogivespecificstreamflow information.Twodrawbacks arethesubjectivemodelcalibrationrequired(whichcanstymyinexperienced users)andthenecessityofutilizingexternal informationtodeterminehowmuchfuturerainfallmayoccur. Although theinitialcostmaybeprohibitiveforsomecommunities,ALERThasbeenshowntobea costeffectivesystem (BurnashandBartfeld,1980).IFLOWS IFLOWS(IntegratedFlood ObservingandWarningSystem)isa government fundedprojectin the Appalachia region (CarnahanandMonro,1980).Itcontains a vast network of automated event reportingrain9agesanda mini-computer based communication systemwhichtransmitsanddisplays therainfalldata-tovariousstateemergencycentersandNWSoffices.Themainvalue ofIFLOWSisproviding automated,relativelydenserainfalldatafortime periodsassmall as15minutes over alargegeographic region.IFLOWSdoes notcurrentlycontainanyrivergages,rainfallestimation procedures, or hydrometeorologicalforecasttechniques.ADVISADVIS(AutomatedFlood Advisory Procedure)wasdevelopedbytheNWSOhioRFCtoprovide a hydrologicforecastandpreparednesscomponentforIFLOWS(Sweeney,

PAGE 152

VanBlargen1411985).Itisaninteractivemodeling systemthatutilizesanAPIwithunithydro graphtodisplayforecasted hydrographs, preparednessplans,andpastfloodcrests.ADVISprovidesoneof the missing components ofIFLOWS,anautomated hydrologicmodelwith theabilitytoyieldaccurateforecastsforanyrainfallsequence.However,the usermuststillmanually estimateandinput observedandforecastedarealrainfallwhichcancreatetimedelays.TheFuture Severalsignificantobstaclesforflash-floodforecastingmethodsremain.Manyareas are not coveredbyIFLOWSorALERTandsufferfromthe problems ofthetraditionalmethods.Evenin areas covered,noeffectivemethodforrainfallforecastingisutilized,andIFLOWSsuffersfromamanualinterfacebetween therainfalldataandhydrologic model.TheNWShaslong-term plans (i.e.,tenyears)fornewtechnology,primarilyNEXRADandAWIPS,withfeaturesdesignedtoovercomemanyof theflash-floodforecastingproblemsandimproveforecasts.NEXRAD(Next Generation Weather Radar)isautomated radarthatisexpectedtobegin nationwide implementation in1988andprovide highqualityspatialrainfallestimates.Also,itwill contain acomponenttocomputeareawideflash-floodpotentialsbasedonthe guidance values(Waltonetal.,1985).AWIPS(AdvancedWeatherandInteractiveProcessing System)willprovide advanced computer processingandcommunicationcapabilitiesatNWSfieldofficesin the 1990's.Onesubsystem ofAWIPS,the ForecastingandLocalAnalysisSystemforHydrometeorology(FLASH),will generate both area-wideandsite-specificflash-floodforecasts(VanBlargan, 1985).Thesystemaimstoprovide improvedforecastsbyassembling highqualityrainfalldataandcombiningitwith improved techniques forQPF,arealrainfallestimation,andhydrologic modeling. VariousinvestigationsareunderwaywithinNWSin severalareas.CurrentQPF'sare not adequate for smallflash-floodareas,but improvements are expectedforavarietyof lead times suchasI-hourprojectionsfromNEXRAD,localanalysis(Belvilleetal.,1978), basinspecificQPF(GeorgakakosandHudlow,1985),and6-hourQPFfromNMC.Procedures willneedtobedevelopedtoweightandmergetheseQPF's. Multi-sensorrainfallestimation techniquesforobjectivelymerging

PAGE 153

142FLASHFLOODFORECASTINGradar,satellite,andgagedrainfallare being developedandtested(Krajewski, 1986).Developmentof aprobabilisticarea-wideforecastingtechniqueisunderway (Zevin, 1985),asisdevelopment of aprobabilisticsite-specifichydrologic modeling system (GeorgakakosandHudlow,1985). Other hydrologic modeling research deals with automaticmodelcalibrationandapplicationinungagedareas (Hydrologic Research Lab, 1985). "Expert" decision systems are being exploredwhichdecideontheoptimumtimetoissueforecastsbasedonpresetdecisionrules(Krzysztofowicz, 1985). Althoughnoneof these developments havebeenimplemented orverifiedoperationally,they are expectedtoyieldimproved techniques inthefuture.Eventhoughimprovementof techniquesisbeing emphasized,someeffortisstillneededonestablishingwhatoutput informationismostusefultowhichusersandhowusersneedtobeeducated inandrespondtotheforecasts.Also, the roles ofIFLOWSandALERTin theAWIPSeraneedstobeestablished.Itseemsthatinadditiontoprovidingdata,these systems will continuetohavea place inmanyareaswhereradar coverageispoor or response timeiscritical,such as urbanlocations.ConclusionsThepresentdirectionof technological developmentindicatesthatflash-floodforecastingwithinNWSisintransition,movingfromtraditionalmethodsthathave changedlittleover timetoasophisticatedsystemthatutilizesadvances in dataacquisition,hydrometeorologicalpredictionmodels,andcomputer technology.Attheendofthistransitionperiod (i.e.,about10years)moretimely,accurate,andinformativeforecasts,both area-wideandsite-specific,willbeavailabletoawidevarietyofusers.Intheinterim,improvements inforecastswillbegained primarilyfromexpanding local flood warning systems. Areas without such systemswillcontinuetorelyonthegeneral warnings produced withtraditionalmethods.

PAGE 154

VanBlargen ReferencesBarrett,C.B.1983TheNWSFlashFloodProgram.Preprints,FifthConferenceonHydrometeorologyatTulsa,OK.Boston,MA:AMS. M3 Belville,J.1978A FlashFloodAid-TheLimitedAreaQPF.NOAATechnicalMemorandum,NWSSR-97.Ft.Worth,TX:NWSSouthern Region,NOAA.Burnash,R.J.C.,R.L.Ferral,andR.A.McGuire1973Generalized Streamflow Simulation System. Sacramento,CA:JointPublication,NOAA/NWSandCalifornia Dept. ofWaterResources. Burnash,R.J.C.,andI.Bartfeld1980ASystemsApproachto the Automation of Quantitative FlashFloodWarnings.Preprints,SecondConferenceonFlash FloodsatAtlanta,GA.Boston,MA:AMS.Carnahan, R.L.,andJ.C.Monro1980TheNational FlashFloodProgram.Preprints,SecondConferenceonFlash FloodsatAtlanta,GA.Boston,MA:AMS.Carter,M.T.,andJ.P.Clark1980IndividualResponsetoFlashFloodWarnings.Preprints,SecondConferenceonFlash FloodsatAtlanta,GA.Boston,MA:AMS.Day,H.T.1970FloodWarningBenefit Evaluation Susquehanna River Basin.NOAATechnicalMemorandumWBTMHYDRO-10.SilverSpring,MD:NOAA/NWS.

PAGE 155

144FLASHFLOODFORECASTINGGeorgakakos,K.P.1985Integrated Hydrometeorological ForecastSystemDesignandTests.NOAATechnicalMemorandumNWSSR-112. FortWorth,TX:NWSSouthern Region,NOAA.Hall, A.J.1981Flash Flood Forecasting,WMOOperationalHydrologyReportNo.18,Geneva,Switzerland:WMO.Hydrologic Research Laboratory1985ActivitiesReport, Quarters 1and4.SilverSpring,MD:Office of Hydrology,NWS/NOAA.Krajewski, W.F.,andK.C.Crawford1982Ohjective Analysis of RainfallDatafromDigital RadarandRain-Gage Measurements. Denver,CO;PresentedatAWRAInternationalSymposiumonHydrometeorology. Krzysltofowicz,R.1985Choice of ActionBasedontheProbabilityof a Flash Flood-Reporttothe Office of Hydrology,NOAA/NWS.Charlottesville,VA:DeptofSystemsEngineering, Univ. ofVA.Linsley, R.K.,M.A.Kohler,andJ.Paulhus1958HydrologyforEngineers.NewYork:McGraw-HillInc. Mogil,H.M.,J.C.Monro,andH.S. Groper1978NWSFlash FloodWarningandDisasterPreparedness Programs.Bulletinof theAmericanMeteorologicalSociety,Vol.59,No.6.Sheridan,J.F.1953Methodsfor Developing Flash Flood Forecasting Tables (MastersThesis).Tulsa,OK:, University of Tulsa.

PAGE 156

VanBlargenSweeney,T.L.1985TheAutomatedFlood Advisory Procedure for the IntegratedFloodObservingandWarningSystem,Preprints,Sixth ConferenceonHydrometeorologyatIndianapolis,IN.Boston,MA:AMS. M5 VanBlargan,E.J.1986Architectural Plans for a FlashFloodForecasting System.Preprints,SecondInternationalConferenceonInteractiveInformation ProcessingSystemsforHydrometeorologyatMiami,FL.Boston,MA:AMS.Walton, M.L., E.R. Johnson, P.R. Ahnert,andM.D.Hudlow1985Propospd On-Site Flash Flood PotentialSystemforNEXRAD.Sixth ConferenceonHydrometeorologyatIndianapolis,IN.AMS.Preprints,Boston,MA:Wright, S.K.1985Flood ForecastingSystemsandEmergencyResponse, a Users Evaluation.Preprints,Sixth ConferenceonHydrometeorologyatIndianapolis,IN.Boston,MA:AMS.Zevin,S.F.,andD.R.Davis1985AProbabilisticApproachto Flash Flood Forecasting.NOAATechnicalMemorandum,NWSSR-112. FortWorth,TX:NWSSouthern Region,NOAA.

PAGE 157

ThisISblankpage

PAGE 158

PARTFOURWARNINGANDRESPONSE

PAGE 159

ThispageISblank

PAGE 160

FLASHFLOODWARNINGEFFECTIVENESSWayneGrahamBureauofReclamation EngineeringandResearch Center Flash floodshavekilledmorethan35Dpeople withintheFrontRangecorri-dor extendingfromFort CollinstoPueblo.Someof themoresignificantflashfloods, in terms of loss oflife,includethe1921flooding along the Arkansas RiveratPueblo; the 1933,34and38flooding along Bear Creek;andthe1976flooding in theBigThompsonCanyon.Somefloods, includingthe1965flooding along the SouthPlatteatDenver,havecausedmuchpropertydamagewith comparativelylittleloss oflife.This report will explore the issue ofwhysomefloods aremorecostlyin terms of loss oflifethanothers.Factors influencing flooding loss oflifeCasestudiesindicatethatthesinglemostimportantfactorrelatedto lossoflifeisthewarning time for the populationatrisk.Simplystated,littleornopublic warninghasthepotentialtoresultinsignificantlossoflife.Adequate public warning ofjustafewhours nearly alwaysresultsin veryfewfatalities.Casestudiesfromactual flash floods willbediscussedlaterin thereport.Otherfactorsthatinfluence flooding loss oflifeinclude:

PAGE 161

150WARNINGEFFECTIVENESSFloodlethality--Floodlethalityisthepotentialofa given floodtocause deathsandinjuriesforthose withinitsboundaries. Thisvariesasa functionofwater depth,velocity,temperature,andamountofdebriscarried.Populationatriskcharacteristics--Importantcharacteristicsofthepopulationthataffecttheirresponsetowarning includetheageofthepopulationatrisk,infirmity,priorknowledgeandunderstanding ofthefloodpotentialandappropriateresponses, previous experience withflooding,knowledge of localterrainandlandmarks,communitysocialstructure(including theextentof informal networks inthecommunityandwhetherfamiliesaretogetheror separatedwhenwarned),andattitudestowardthewarning, including experience withpriorfalsealarmsormisin formation. Environmental conditions--These aretheenvironmentalconditionsthatoccur bothpriortoandduringtheevacuation processthatcanaffectitssuccess.Forexample, long periods of rainmayserveasanenvironmental cuethatfloodingislikely,thusreinforcingthewarning message. Conversely, local floodingpriortoaflashfloodcanmakeevacuationdifficult,ifnot impossible. Conditionsassociatedwithflashfloodingcandamagepowerandcommunication networks. Also,heavyrain,severecold,lightning,andotherstorm eventscanmakeleavingtheshelterof ahomeorautomobile veryunattractivetothepopulationatrisk,furtherdelayingorpreventing evacuation.

PAGE 162

Graham151Flash floodsthatoccuratnight,especiallyduring hourswhenmostpeoplearenormallyasleep,presentmanydifficultproblems. Eventsmaybemoredifficulttodetect,warning decision-makinganddissemination of warning messagescanbedelayed, evacuation in darknessismoredifficultandvisual confirmationofanapproaching flood,whichoftenprompts evacuation,maybetotallyabsent.Convergence--Convergenceisthemovementofindividualsintothedanger zone, whethertoretrievepossessions,assistfamilymembersandothervictims,orjustwatch. This includessafetyofficialsengaged in rescueoperations.Convergence deathsresultsfromindividualsenteringorreturningtothe dangerzonetoretrievepossessionsorhelpothers,fromattemptingtodrive,walk, orswimthrough floodedareas,orfromsightseeing tooclosetothe flood. Deathsduetoconvergence are usuallyfewin number, but are acommonfeatureof majorfloods.WarninginNineHistoricCases Pueblo, Arkansas River, June 3,1921Floodin9priorto1921promptedtheestablishmentoflevees designedtoprotectagainsta flood of 40,000ft3/s.Thiswasslightly9reaterthanthemaximumdischarge ofthefloodof1894.Heavyrainsfellintheregion westofPuebloonJune 2and3 withintenserainfallingontheafternoonofJune3.TheriveratPueblostartedtoriserapidlyat5 p.m.Thefirstwarning oftheapproaching flood reachedthecityabout 6 p.m.onthe3d,statingthata wallofwaterwasrushingdowntheriver.

PAGE 163

152WARNINGEFFECTIVENESSMessengers were sent outatoncetowarnthepeoplelivinginthelowlandscalledPeppersauceFlats.Hundreds of people rushedtotheleveestowitnesstheapproachofthegreatwall of water, notthinkingthatthecitycouldbeinundated,asthelevees were believed highenoughtoprotectit.Thesudden breaking oftheleveesatabout 8:45 p.m. cutoffthepeoplefromthehigher land,andin endeavoringtoescapemanywere drowned, as weremanyothersinthehouses inthelowlandswhohadrefusedtoheedtheflood warning.Themaximumstageoccurredatmidnight.Thelevees were then overtoppedbymorethan 6feet.Thepeakdischargewas103,000ft3/s.Fatalityestimatesforthisflood rangefrombetween78to500. Possibly abetterunderstanding ofthemagnitude oftheflood approaching Pueblo, or abetterwarning messagewouldhaveresultedin a reducedfatalitycount. Denver,FailureofCastlewoodDam,August 3,1933CastlewoodDamwaslocatedonCherryCreekabout35miles upstreamfromDenver.Theintegrityofthedamhadbeenquestioned inthelocalmediaforyearspriortothefailure.Thus,thepeople of Denver were probably awareofthedamsexistence.Heavyrainsduringthenight of August 2-3 caused watertoflow throughthespillwayandoverthetop ofthedam.Shortlyaftermidnightthedam'scaretakerheardtherumbling ofthefloodandheseizedalanternandrandowntolookatthedam.Herealizedthatthedamwasbreaking, butwasunabletousethetelephonetoinitiatethewarning process because wires

PAGE 164

Graham153were alreadydown.Thecaretakerthen drove12milestoCastleRockandatabout 2:30 a.m.madetelephonecallswhichstartedthewarning process. This flood occurred beforethedays ofdialandpush-button phones. Telephoneoperatorsin ParkerandSullivan "sent outthedangerflash"totheirsubscribers.Today's "improved" telephone technology prevents arepeatofthistypeofwarning dissemination technology. Policeandfirevehicleswere, within minutesoftheinitialtelephonecall,cruisingthroughthethreatenedarea within nenver withsirensscreaming. Flooding beganatColorado Boulevardatabout 5:40 a.m.Structuresin Denver weredamagedbut veryfewweredestroyed.Twofatalitieswereattributed,atthetime,tothe flood. AwomandiedatParker12hoursafterthestartof inundation.Shewascurioustoviewtheflooddamageandwasridingbyhorsebackwhentheanimal threw herintothewater. Another person,livingnearthemouthofCherry Creek, steppedintoa deep hole while wading toward higher ground.Hehadapparentlybeenwarnedandhadspentconsiderabletime in packinghispossessions.Newspaperaccountsindicatethatmanypeople, followingthewarning, wantedtoviewtheapproachingflood. These"convergers drove nearthebanks of Cherry Creekandatleastoneveryclosecallwithdisasterwasdescribed inthemanyarticlespublishedonthefloodanditsresultantlosses.Bear CreekandMtVernonCanyons, 1930's Bear Creek experiencedthreemajor floods inthe1930's.Floodin9onJuly7, 1933, claimedthelivesof seven people.Thefollowingyear

PAGE 165

154 WARNING EFFECTIVENESSsixpeople diedonAugust9.OnSeptember 2, 1938,eightmorepeopledied.These floods,likemanyotherrain-induced events along the Front Range, occurredinthe afternoonandevening.Onlysketchy informationisavailableconcerning the warningassociatedwith thesethreefloods.Somewarning ofresidentsdid occur in the1938flood.A rancher inMountVernonCanyonphonedaGoldenoperator with the messagethata cloudburst floodwasrollingdownthe gulchandthatitwouldbein BearCreekCanyon,above Morrison, inhalfanhour. This messagewasphonedtotwotelephoneoperatorsin Morrisonwhointurncalledallof the hundredstationsin theCanyonservedbythe switchboard.Onlytwobuildings in theentireresorttownof Morrisonwereleftstanding.Denver Metropolitan Area, SouthPlatteRiver, June 16,1965TheDenverMetropolitanAreawashitbyanoutstanding flood the night of June 16.Itwasthelargestfloodonthe SouthPlattein thehistoryof Colorado.Thetotaldamage,adjustedto1986dollars,exceeded$1billion.Onlyonefatalitywasrecorded intheSouthPlatteValley throughtheDenverMetropolitan Area. This favorablefatalitycount, consideringthemassivedestructionanddevastation,canbedirectlyattributedtothetype,numberandqualityof warningsthatwereissued throughoutthefloodplainareas.ExtremerainfallamountsfellinthePlumCreekBasin.Officialsin upstream communities radioed or telephonedofficialsin the downstreamcom-

PAGE 166

Graham155munitiesofLittleton,EnglewoodandDenver. Warnings were issuedbyfiremen,police,radioandtelevision.Nationalnewsmediawascarryinginformationontheflood,someofwhichwaserroneous. Flood plain occu pants intheupper reaches weretoldtheyhad10to15minutestoevacuate.Itactuallytookuptotwohours for the watertoarrive.Warningprecededthefloodingbyupto4 hours inthelower reaches(portionsof Denver).Itisinterestingtonotethatheavyrain did notfallalongtheSouthPlatteRiver through Denver. Thisseemedtorefutetheideathatmajor floodingwasimminent.Manypeople refused tobelievethattheSouthPlatteRiver could flood.Spectatorsbecameasignificantproblemtodeal with duringtheevacuation.Littletonofficialsmadethefollowingcomment"Weprobablyhad5,000extrapeople inLittletonwantingtoseewhatwasgoingonanddarn near everyoneofthemdrovetheirowncar.Agoodpartofthiswasbroughtonbytheradiostationsannouncing where(theflood)wasandwhatwasgoing on--howbaditwas." (Worth,page23)Oneperson died of aheartattackwhile walkingtohigh ground.Hehadearlierevacuated but returnedtohis house.Hisfatalwalktohigh ground beganwhenwaterwas4feetdeepinthehouse.RockyMountain National ParkandEstes Park.FailureofLawnLakeDam,July15,1982

PAGE 167

156WARNINGEFFECTIVENESSLawnLakeDamwas26feethigh. Less than700acre-feetofwaterwasreleasedwhenthedamfailedatabout 5:30a.m.onThursday, July151982.LawnLakeDamwaslocated inRockyMountain National Park, 4airmilesfromthenearestroad ortelephone.There were asmanyas25hikerscampedintheroadless area immediately downstreamfromthedam.Thecampers receivednoofficialwarning but environmental warnings, suchasseeingtreesbreakingandhearingtheroaroftheriver,describedbymanyaslikecontinuous thunder, enablemostofthesecamperstoescape. Nonetheless,onecamper inthisareawasswepttohisdeath.A garbagecollector,whilemakingpickupsontheroadnearestthedam,thought ajetwascrashingand then sawmud and debrisontheroad.Hethen drove ashortdistanceandused a National Park Service emergency telephonetoreporthisobservationtotheNational Park Servicedispatchcenter.This telephonecallsetoffaseriesofactionswhichresultedin thousands of people evacuating or notenteringflood-threatenedareas.TheNational Park Servicewarnedandevacuated people occupyingthemostthreatenedportions oftheAspenglenCampgroundwhere275people were camped.LawenforcementandotherGovernmentofficialswarnedandeva cuated people in LarimerCountyandEstes Park. EstesPark'sonly radiostationlearned aboutthedamfailureonapolicescannerandthe-stationwasinstrumental in spreadingthemessage ofthedamfailure.TwofatalitiesoccurredatAspenglenCampgroundwhencampersleftanarea ofsafetyandtriedtowalkintoislandcampsites.Bothdeceased campershadbeen

PAGE 168

157Grahaminformed oftheimpending flood (but notofadamfailure)byothercampers.CaseStudies Outside of Colorado Additionalinsightregardingthevalue ofanadequate warning processcanbegainedbylookingatthe warning experienceassociatedwithflashflood eventsoutsideof Colorado.Muchofmyworkhas focusedondamfailurewarningprocesses.Itisforthisreasonthattheevents chosenfordiscussionarealldamfailures.Thefourdamfailuresthatwillbediscussedare:BuffaloCreekCoalWasteDam, West Virginia;TetonDam,Idaho; Kelly Barnps Oam,Georgia;andD.M.A.D.Dam,Utah.Eachcase study hasanimportantstoryassociatedwithit.BuffaloCreekCoalWasteDam,WestVirginia,February 26,1972Buffalo Creek,WestVirginia,isfarfromColorado, butitisrelevanttoanydiscussionof warningsassociatedwithflashflooding.Atthetime offailure,thewaterwasabout46feetabovethestreambedandtheimpoundmentcontained about400acre-feetofwater.Thedamfailedat8:00 a.m.ona Saturday, during a flood with a 2-year frequencyofrecurrence.Representatives(thedamwasownedbyasubsidiaryofPittsonCoalCompany)wereatthedamthemorningofthefailure.Theseindividualsrealizedthatthereweresomeproblemsandwere takingsomeactiontopreventdamfailure.Thewarning processfailedbecausecompanyofficialsdid notmake

PAGE 169

158WARNINGEFFECTIVENESSthedecisions towarnthe publicatrisk.Infact,theseniordamownerrepresentativeofficialonthesitedismissedtwodeputysheriffswhohadbeensenttothe area to aid in the evacuation. Responsetothemeagerwarnings disseminatedwasinadequate becausefalsealarmshadoccurredonatleastfourearlieroccasions.Theleadingedgeofthefloodwatertraveled the IS-mile length of the BuffaloCreekValley in about 3 hours,killing125people.About500homesweredestroyedandabout 4,000 peoplewerelefthomeless. TetonDam,Idaho, June 5,1976TetonDamwaslocated northeast of IdahoFalls,Idaho.Thedamfailedat11:57 a.m.ona Saturday, duringitsinitialfilling.Thereservoircontainedabout 252,000acre-feetof wateratthetime offailure,andthereservoirwater surfaceelevationwasabout275feetabovetheoriginalvalleyfloor.OnThursday, 2 days beforethefailure,construction personnelfoundtwosmall seepsatthe downstream toe ofthedam.Thewaterwasclearandtotaledabout100gallons per minute.OnFriday, 1daybefore thefailure,a smaller seepwasobserved in adifferentlocation.Clear waterwasalsoflowing out ofthisseepanditwasnot considered a problem. A Reclamationemployeeremainedatthe damsiteuntil12:30 a.m.onJune 5,thedayofthefailure.Thedamwasthen unattendeduntilabout 7:00 a.m.Between7:00and8:00 a.m. of thedayofthefailure,a surveycrewdisco-

PAGE 170

159Grahamveredslightlyturbidleakage.Asearlyat9:30a.m.,theProjectConstruction Engineer consideredalertingarearesidentsbuthedecidedthatanemergencysituationwasnotyetimminent. Concern about causing panicwasonefactorconsidered in the decision nottoalertarearesidents.Researchershavefoundthatpanic almost never occursonalargescaleindisastersituationsalthough theelectronicandprintmediaoftenperpetuatesthepanic myth.Atabout 10:00a.m.,alargerleak,flowingturbidwater,wasdiscovered.Between10:30and10:45a.m.,lessthan1-1/2hours beforefailure,theProjectConstruction Engineernotifiedthesheriff'sofficesinMadisonandFremontCountiestobegin evacuation of downstreamareas.Damfailureinundationmapswerenotavailableatthe time ofdamfailure.Theevidenceindicatesthatauthoritieswerestillable,without inundationmaps,toaccessanddeterminewhichareaswereatrisk.Everyknownmeansof communicationwasusedtotransmitthe warningandevacuation messages. Peoplelivingin areas within20miles of TetonDamlearned of thefailureas follows (IdahoFallsChamberofCommerce):Radio -44percent Neighbor 28percent Telephone -7 percent Police 7 percent Other -14percentThefailureresultedindamagesthatwereestimatedtobeabout $0.5billion.Morethan 35,000 peoplewereevacuatedfromtheirhomes.

PAGE 171

160WARNINGEFFECTIVENESSTheoveralleffectivenessofthewarningandevacuationcanbejudgedbywhat happenedatSugar CityandRexburg,twoofthecommunitiesclosesttothedam.SugarCity,acommunityofabout600people,islocated about12miles downstreamfromTetonDam.Floodwaters reachedthiscommunityabout 1 hourafterTetonDamfailedwith depths ofupto15feetbeing recorded.Nofatalitieswere recorded in SugarCity.About80percentof Rexburg, with a populationof10,000 people,wasinundatedtodepthsof6to8feet.Floodwaters reachedthiscommunity,locatedabout15miles downstreamfromTetonDam,about 1 hour40minutesafterTetonDamfailed.Twonondrowningfatalitieswere recorded in Rexburg. Despitethewarningsthatwereissued,therewere atotalof11fatalitiesattributabletothefailureof TetonDam.A 21-year-old personfishingjustbelowthedamdrowned.Hewastheonly deceased personwhohadnot received adamfailurewarning messagefromsomesource.Allotherpeoplewhodiedhadvaryingbeliefsordegrees of knowledge concerningthedamfailureandassociateddanger.Anelderlycouplefailedtoevacuateafterreceivinganin-person warningfromtheir23-year-old grandson.Thecouple drowned. A groupofthreemendrovefromanarea ofsafetyintoanareathatwassoontobeflooded inordertohelpremovehouseholditemsfromthehomeof arelativeofoneofthethree.Thehomeownerwasquotedassaying: "Itold(thethreemen)therewouldbealotofwatercomingdownthecanyon, but theyseemedtothink theyhadtimetoput another load inthatpickup(truck).Iwasawfullyscared,I thought Iwouldhave aheart

PAGE 172

Graham161attack.Ihadtoleave."(IdahoFallsChamberofCommerce,page70)Thethreemenremainedatthehomeanddrowned. A 94-year-oldwomandiedafterbeing evacuatedfromthe floodarea.Another person died ofanaccidentalgunshotwoundsustainedwhile removing agunfromhisvehicle.Twopeople diedfromheartattacks.Awomanlivingoutsideoftheflood-damaged area committedsuicide5 daysafterthedamfailure.Kelly BarnesDam,near ToccoaFalls,Georgia,November6,1977Atthetimefailure,Kelly BarnesDamimpoundedabout630acre-feetofwaterandthewaterwasabout34feetdeep.Thedamfailedatapproximately 1:30 a.m. during a floodthattheGeological Survey estimatedtohave a 10-year frequency ofrecurrence.Thewarning processfailedbecause thedamwasnot being monitored. Thus,thedamfailurewentundetecteduntilfloodwaters crashed throughthecampusof ToccoaFallsCollege, drowning39peopleallofwhom,atthetime ofthefailure,werelocatedwithin 1 mileofthedamand500feetof Toccoa Creek. Thiswasa verylargenumber,consideringthatonly afewhundred peoplewereatrisk.Thispointsoutthatlargenumbersof peoplecanperishwhenlethalflashfloodsarenotpredictedordetected.O.M.A.D.Dam,nearDelta,Utah, June 23,1983D.M.A.D.Damwasnamedusingthefirstlettersof fourprivateirrigationcompanies.Thedamfailedona Thursdayatabout 1:00 p.m.Thedam,locatednortheastofDelta,contained about 16,000acre-feetofwater,with

PAGE 173

162WARNINGEFFECTIVENESSamaximumdepth of30feet,atthetime offailure.This case studyisnearly a textbookexampleofhowanemergencyaction planandwarning system shouldbedevelopedandoperated. Duringthedays preceding thefailure,construction crewswereatthedamtryingtoprevent spillwayfailureduetoheadcutting inthedownstream channelwhichwasmovingtoward thedam.Thedamwasbeing monitored (attended)24hours a day. Therewasanawarenessamongresidentsintheareathatthedammight break. Before thefailure,residentsweredirectedtolistento the Delta radiostation.Thestationremainedontheair24hours adaypriortoandimmediatelyafterthefailure.Thelocal publicsafetyofficialshadplannedonchannelingallrelevant information concerning thesafetyorintegrityof thedamthrough thestation.Asheriffwasintheradiostudio for the purpose ofalertingtheresidentsof theimminentdanger of apossiblefailurewhenwordwasreceivedbythesheriffthatthedamhadactuallyfailed.Within60seconds of thefailure,thesheriffwasreportingliveon-the-air.Alistof peoplelivingin the floodplainandtheirtelephonenumbershadbeenpreparedpriorto thedamfailure.ThesepeoplewerecalledbyMillardCountydispatchersandsecretaries.Sheriffdeputies alsowentdoortodoor notifyingresidentsthattheywereinimmediatedangerandadvisingthatthey leave.Damfailureinundationmapswere notavailablepriortothefailure.TheMillardCountyAdministratorindicatedthatthetelephonelistwasprepared baseduponaneducated guess

PAGE 174

Graham163ofwhichareasweremostflood prone. Additionally,priordamfailuresinthearea proved useful in determiningwhichareaswereatrisk.Newspaperreportsindicatedthatabout500people evacuated.Thereports alsostatedthatthe evacuation"wasalmostlikearehearsal,"andthat"peoplewerecalmandmethodical.""Mostpeopleweregonewithintwohours"and"themajori tywenttothehomesofre1ativesandfriends. "(Madsen)GunnisonBendDam,located about 8 miles downstreamfromD.M.A.D.Dam,wasintentionallybreachedinordertoprevent acatastrophicor uncontrolledfailureof thestructure.Thisworkwascarriedout under a planmadedaysbefore theD.M.A.D.Damfailure.Theleadingedgeof the floodmoveddownstreamfromD.M.A.D.Damatabout 2 miles per hour reaching thecommunities of OasisandDeseret during hours of darkness,some7to12hoursaftertheD.M.A.D.Damfailed.MuchdamageresultedfromthefailureofD.M.A.D.Dam,althoughfewhomesweretotallydestroyed. Aman,thought tobeatransient,diedafteranunsuccessful attempttocrosstheswollen Sevier River inthecommunityof Deseretbyclinging to a cable strung across theriver.Thebridge inthiscommunityhadbeenwashedout.

PAGE 175

164References Pueblo, Arkansas River, June 3,1921WARNINGEFFECTIVENESSFollansbee, RobertandEdwardJones. 1922."TheArkansas River Flood of June 3-5, 1921."U.S.GEOLOGICALSURVEYWATERSUPPLYPAPERNO.487. Denver, Failure of CastlewoodDam,August3,1933"FourWatchingFloodSweptDownSpeer Blvd."August4, 1933.ROCKYMOUNTAINNEWS."ManyWarningsGivenbyPhone."August4, 1933.ROCKYMOUNTAINNEWS."Tells ofRidetoGiveAlarm."August4, 1933.ROCKYMOUNTAINNEWS."TimeTableGivesFlood's History."August4, 1933.ROCKYMOUNTAINNEWS."PoliceandFiremenSaveManyin Flood."August3, 1933.DENVERPOST.BearCreekandMt.VernonCanyons, 1930's"41HaveDiedinBearCreekDeluges." September 4, 1938.ROCKYMOUNTAINNEWS."TomClennanandWifeareAmongEightDrownedin CloudburstonBear CreeL" September 3, 1938.DENVERPOST."TwentyorMoreTownsareCutOffOrUnderWater." September 4, 1938.ALAMOSADAILYCOURIER.DenverMetropolitan Area, SouthPlatteRiver, June 16,1965Matthai,H.F. 1969. "Floods of June1965inSouthPlatteRiver Basin, Colorado. U.S.GEOLOGICALSURVEYWATERSUPPLYPAPERNO.1850B."NewFloods Hit in Colorado." June 18, 1965.ROCKYMOUNTAINNEWS."OnlyTwoKnownDeadWithFive Listed Missing."August4, 1965.ROCKYMOUNTAINNEWSWorth, MartiF.,andBenjaminF.McLuckie,"GettoHighGround!TheWarningProcess in the Colorado Floods, June 1965."TheDisasterResearch Center,OhioStateUniversity, 1977.RockyMountainNational Park,FailureofLawnLakeDam,July 15,1982Graham,WayneJ.,andCurtisA.Brown.1982."TheLawnLakeDamFailure -A Description of theMajorFlooding EventsandanEvaluation of theWarningProcess."Bureauof Reclamation

PAGE 176

GrahamBuffaloCreekCoalWasteDam,WestVirginia, February 26,1972"DisasteronBuffalo Creek." ACitizen'sReportonCriminal Negligence in aWestVirginiaMiningCommunity.165Erikson,KaiT.1976.EVERYTHINGINITSPATH-DESTRUCTIONOFCOMMUNITYINTHEBUFFALOCREEKFLOOD,SimonandSchuster,NewYork."ThePittstonMentality." JuneII,1972.CHARLESTON,WESTVIRGINIAGAZETTEMAIL.Runner,G.S.1974. "FloodonBuffaloCreekfromSaunders toMan,WestVirginia."U.S.GEOLOGICALSURVEYHYDROLOGICINVESTIGATIONSATLASHA-547.TetonDam,Idaho, June 5,1976Eikenberry,F.William, Chairman. April 1977.FAILUREOFTETONDAM-AREPORTOFFINDINGS.IdahoFallsChamberofCommerce.Winter 1977.THETETONDAMFLOOD.Witness Statements. ObtainedbyDepartment ofInteriorSpecialAgentsFollowin9 thefailureofTetonDam.Kelly BarnesDam,NearToccoaFalls,Georgia,November6,1977Foster,NeillK.1978.DAMBREAKINGEORGIA-SADNESSANDJOYATTOCCOAFALLS,HorizonBooks.Sanders,C.L.,andV.B.Sauer. 1979. "Kelly BarnesDamFloodofNovember6, 1977, near Toccoa, Georgia. "U.S.GEOLOGICALSURVEYHYDROLOGICINVESTIGATIONSATLASHA-613.D.M.A.D.Dam,NearDelta, Utah, June 23,1983"--AndThenItBroke."TheWestMillard Flood of1983;theDMADDisaster Souvenir Publication,MILLARDCOUNTYUTAHGAZETTE."TheFloodof 1983." June 30,1983.MILLARDCOUNTY,UTAHCHRONCLE.KNAKRadioPersonnel. Personal interview held January 27, 1984, in Delta, Utah.Madsen,Reed,andT.VanLeer. June 24, 1983."DamCollapseLeavesMillardTownsAwash."DESERETNEWS.Pearson,Robyn.MillardCountyAdministrator. Personal interview held January 27, 1984, in Delta, Utah.

PAGE 177

THEBOULDERFLASHFLOODDETECTIONANDWARNINGSYSTEMDonaldG.VanWieSystems Concepts of Colorado,Inc.Intheearly1970'stherewasalimitedawareness ofthethreatposedbyflashflooding in Boulder County. Then,40milestothenorth,theBigThompsonCanyonwasravagedand139liveswerelost.Theissueoflocalpreparednessmovedfromacademicinteresttopressingurgency.Thelegacy ofgraphicimages, inprintandintheminds ofthosewhoassistedintheBigThompsondisaster,galvanized a keeninterestindeveloping a flooddetectionandwarning systemthatcould reducethelossoflivesfromasimilarflood in Boulder County.Inthisatmosphere,cooperationwasexcellentamongvariouspublicsafety,floodcontrol,andemergencymanagementagencies.TheUrbanDrainageandFlood ControlDistrict(UDFCD)offeredtoputuphalfofaninitial$150,000 flooddetectionsystem.Thematching funds werecontributedbyBoulder CountyandtheCity of Boulder,andBoulder County assumedresponsibilityforsystem maintenanceandoperation.AconditionofthefundingfromUDFCDwasthedevelopment ofanadequate flood warningplan,with annual reviewandtesting.Theplanningeffortreacheditspeakinearly197B.Representativesofpublicsafety,emergency management,andfloodcontrolagencies oftheCity of Boulder, Boulder County,theUniversityof Colorado,theUDFCD,andmanyothers,workedtodevelop asuitableplan.Twomajor components emerged:first,a systemtodetectfloodingandmakedecisionsonwarningandevacuation;andsecond, a planforthedisseminationof warnings to-the public. i_n_g.. a.r:
PAGE 178

TheWarning Dilemma o oa.
PAGE 179

168BOULDERWARNINGSYSTEMWorkbytheCorps of Engineersandotherhydrologicalconsultantsindicatesthatflood flows can developinthecanyonareaswithin1to2 hours of peakrainfallin a 100-year stormevent.Thetimefora floodtotraveldownthechanneltomajor populatedareasisconsiderablyless--typically30to50minutes.Inaworst-casesituation,floodingcan occur in Boulderwithin3 hours ofthebeginning ofrainfall.Thetimerequiredforthedetectionandwarning processwasanalyzed working backwardfromthetime of floodarrival.Theplannersproposed a warning processthatwouldusespecialalertradios,sirens,pUblic address systemsonfireandpolicecars,andthebroadcastmedia.Thewarning process acknowledgedtheneedforthepublictohearspecificandmutually confirming messagesfrommultiplesources inordertobeinducedtoact.This warning processwasestimatedtotake30to40minutes;toallow timeforpublicresponse,theprocesswouldhavetobeginatleastone hourbeforefloodarrival.Theproposed warningprocess,andthedirectionofthepublic'sresponse,islabor-intensive.On-duty personnel mustbesupplementedbyoff-dutyandvolunteerpersonnel inordertofullyexecutetheplan.Further,someofthepublicsafetyfacilitiesarethemselves inthefloodplain,andmeasures mustbetakentomoveequipmentandtakeotherprotectiveactionsbeforepublicwarningsbegin.Thismobilizationprocesstakesanotherhour, and,therefore,must begin about 2 hours before floodarrival.Inordertotriggeramobilizationdecision,thedetectionsystem mustbefullyoperationalstillearlier-twoandahalftothreehoursbeforefloodarrival.Comparison ofthetwotimelinesshowsthat:Thetimerequiredforwarningisgreaterthanthefloodtraveltimedownthechannel.Thedecisiontowarnthepublic,therefore,mustbemadebeforetheflood hasgatheredupstream. Mobilizationofthepublicsafetysectormust beginbeforeenoughrainhasfallentobesurethata floodwilloccur.Thedetectionsystem mustbestaffedandoperationalfromvirtuallythebeginningofthestorm.Thecentralgoal ofthedetectionandwarning systemistoproduce warningsthatarebothtimelyandaccurate.Sinceanysuccessfulwarningoperationwillbehighlydisruptive,itisessentialthatwarningsbe

PAGE 180

VanWie169implemented onlyata timewhenthereishigh confidencethatfloodingwilloccur.Itcanalsobeexpectedthatanyfalsealarmswillseverelydamagethecredibilityandeffectivenessoffuturewarnings.Yetthetimeconstraintsindicatethatpreparationforwarning must begin longbeforeanycertaintyof a floodexists.Itbecamecleartoplannersthatsuccess ofthesystemwouldhingeonthewiIlingnessofthepublicsafetyagenciestotobeginmobilizationperhaps dozens of timesforeach time warningsareactuallyissued.That commitmentwasmade,andresultedina high degree of involvement oftheBoulder CountySheriff'sDepartment inthedevelopment,operationandmaintenance ofthesystem. Systemeffectivenessisalsodependentonintegratinginformationfrommultiplesources.Thefollowingmakemajorcontributionstothedetectioneffort: Weather Serviceandprivatemeteorologicalforecasts weatherradarfromLimon, ColoradoandCheyenne,Wyomingevent-driven,telemetryreportingraingages inthefoothillsautomaticallyreportingstream gages decisionaids,intheformofrainfall-runofftables,hydrologicpredictionprograms,inundationzone maps,andformatted messages.Eachofthesehas a unique value inthesystem. Accurate meteorologicalforecastsareessentialtostartingthedetectionprocess.Without competentanalysisofsynopticpatternsandmesoscaletrends,thedetectionprocess wouldrequirethecommitment of personnelvirtuallyevery timeitrained.Butwithreliableforecasts,mobilizationofthedetectionprocess canstartearly,yetstillberestrictedtothosesituationsin whichthereisknownatmosphericpotentialforflood producingstorms.Weatherradarfillsthecriticalgapbetween a meteorologicalforecastandgroundtruth.Presentmeteorologicalcapabilitiescanidentifythepotentialforflood producing thunderstorms over Boulder County, but cannotidentifyasinglebasinortime ofoccurrence.Real-time weatherradarallowsdetectionpersonneltotracktheformation,growth,location,movementandseverityofthespecificstormcellsof localinterest.Theremoterainandstream gages allowdirectanalysisofrainfallreachingtheground.Ifthedetectionsystem dependedsolelyonthisdatato

PAGE 181

170BOULDERWARNINGSYSTEMstartoperations,warnings mightcometoolate.Oncedetectionoperationsareunderway, however,datafromautomatic gagesisthecentraltoolforevaluatingthesituation.Combinedwithradarandsynopticdata,dataonactualrainfallalsobecomesa majorpartofthepredictionsystem. _I.f!.t.Ul.e.t.e.c :t _i.C!.f!._S)'.s.t.e.m. TheflooddetectioncenterislocatedadjacenttotheBoulder Regional CommunicationsCenter,which providespolice,fire,andemergencyservicedispatchingformost ofthecounty. Weatherradarimagery,rainandstreamdata,anddecisionaidshave beenmadeavailablethere,supportedbyafaulttolerantcommunications systemandanuninterruptablepowersupply.Adefinedorganizationalstructurespellsout job assignmentsforthevariouspersonnel involved intheflooddetectionprocess.These personnelincludepublicsafetyofficials,cityandcounty floodcontrolengineers,andjurisdictionheads.Fromtheflooddetectioncenter,they can communicatedirectlywiththecontractmeteorologicalservice,NWS,andfieldobservers.Onceinitiatedbygeneral meteorologicalconditions,flooddetectionoperationscenteroninterpretingdataonrainfallinthe180square mile flood catchment zone inthefoothills.Intheearlieststagesofthesystem,volunteerfirefighters,alertedfromthecommunicationscenter,readraingagesandmannedstaffgagespaintedonbridge abutmentson7creeks.This systemwasonlymarginallyworkable. Therewasanenormous impactonthepUblicsafetycommunication network asquestionsanddataflowedfromthedetectioncentertoobserversandback.Interpretationofthedatawassometimes impossible becausetheinitialconditionoftheraingageswasunknown.Anditwasdifficultforvolunteerstodedicatemanpowertothistaskforthetimeperiodsrequired.Thevolunteersystemwasretainedas a backup measurewhenautomaticallyreportingraingages wereinstalled.Theremote gagesarebattery-poweredandreportbyradiowiththeaccumulation of eachmillimeterofrain.Theinitialsystemconsistedof 8raingages and 4 stream gages,allintheBoulderandFourmile Creek watersheds above Boulder. DatawasrecordedonpapertapeanddisplayedonaLEDwalldisplay.Datareductionwasdonemanually using Thiessen polygon averagingtechniquesonlO-minuteintervalsduringintenserainfallperiods.Sincedata

PAGE 182

VanWiefromautomaticraingagesisimmediatelyavailable,reliable,andobjective,confidenceinthedetectionsystemgrewrapidly.171 Theremarkable improvements indetectionsystem performance inducedthecountytocontinuetoexpandthesystemintootherbasins;by1986,42raingageshadbeeninstalledalong with12stream gages coveringtheentirefoothillsarea.Asthequantityofdataincreased,thedatacollectionsystem evolvedfrompaperlogging,toadedicatedmicroprocessor withALERTsoftware,andfinallytoafullymulti-tasking,multi-terminalcomputer capable ofextensivedatareductionandmultiplesimultaneous flooddetectionfunctions.Changes inthedatacollectionsystem weredrivenbytheneedforflooddetectionpersonneltorapidlyandaccuratelyassimilatedatafromnumeroussites,tospotpotentialproblemareasquickly,andtoidentifythetype ofactionrequired. While manualtechniques wereacceptableforafewgages, expansionmadeautomationimperative.Thelack ofsuitablecommerciallyavailablesoftwareledtheBoulder CountySheriff'sDepartmenttechnicalstafftodevelopSTORRM,theSheriff'sTelemetry OperatedRainfallandRiver Monitor.TheSTORRMsystemisacollectionofinterrelatedprograms using a shared data baseandcommonuser-definedsystemparameters.Oneprogram provides continuousdatacollection,validation,filing,andarchiving.A second program,calledMonitor,alsorunscontinuously;itmonitorsrainfallamountsandstreamlevels,generatesalarms basedonhydrologicactivity,calculates,stores,anddisplaystheaveragerainfallin eachbasinoverseveraltimeperiods,andwatches systemintegrity.Theoutputsofthisprogram inclUde acontinuouslyupdated screendisplay;displayscreensareinstalledintheregularworkareasof flooddetectionpersonnel.Thisdisplayisalsoavailabletooutsideusers,such as NWS, byremoteterminal.Thealarms generatedbytheMonitor programarereceived intheBoulder Regional CommunicationsCenter,wheredispatchersnotifyappropriatepersonnel.Alarmsincluderainfallrate,rainfallamount, streamlevel,andstreamrateofrise.Dataintegrityalarms provideearlynotificationofCPUordatacollectionfailure,orfailureofanyofthethreedatarepeatersrelayingdatafromthegages. Pointrainfalldataareconvertedtoarearainfallusing a weighted averagetechnique.Thearearainfallvaluesarethen usedtoproducerainfall

PAGE 183

172BOULDERWARNINGSYSTEMaveragesforthevariousbasinsandsub-basins.Thesearedisplayed,as well as used astheinputstoa hydrologicanalysisprogram. Amapshowingthelocationandamountofrainfallthroughoutthegagedareacanbeproduced with a timeresolutionof10minutes,andaspatialresolutionof 2.25 squaremiles.Atypicalrainfallmapisshownin Figure 2. Another program used during flooddetectionoperationsanalyzestherecurrenceintervalofthebasinaveragerainfall,estimatesresultingstream flowanditsrecurrenceinterval,andprovides "whatif"outputsbasedonprojectionofthepresentrainfallratesover3and12hourperiods.Moresophisticatedhydrologicanalysisroutinesarecurrentlyinthedevelopmentandtestingstages.TheSTORRMsystem allows simultaneousoperationof a simulated event alongsiderealtimedatacollection.Thisfeatureprovidesanexcellenttrainingandtestingtool.Asimulationdatabasecanbedevelopedtorepresentanytype of storm event und outcome. Systemuserscan thenbegivenfreeuseofthevariousanalytictools,as well assimulatedinputsfromothersources such aradar,togainexperiencein use ofthesystemortosharpentheirdecisionmakingskills. Thesystem has been in placeforseveralthresholdevents.WhileuseofSTORRMhas not ledtoadecisiontowarnthepublic,therehave beenseveraloccasionsonwhichissuanceof warningswasavoided only as aresultoftheremoterainfalldataavailableattheflooddetectioncenter.Thesystem has beenexercisedonetothreetimesannuallyfortestingandtrainingpurposes,andhasenteredthemobilizationphaseonrealeventswith aboutthesamefrequency.Asfaras they have gone,therealeventshave confirmedtheexperiencesofthesimulatedevents,andthishasincreasedconfidence inthesystem.Directionandguidanceforoperationalrefinementsandfuturedevelopment havecomeprimarilyfromtheorganizedcritiquesheldaftereach use ofthesystem. Futureeffortswillfocusonincreasingtheautomation ofdataanalysisinordertoreducethenumberof peoplerequiredtostaffthedetectionoperation.Likewise,furtherautomation ofthewarning processwillreducestaffingrequirementsfordisseminationof warning. Thesestaffingreductionswillproduce correspondingreductionsintherequiredmobilizationtime,which inturnwillimprovethetimelinessof warnings.

PAGE 184

O .. tdSTORRM INTERVAL RAINFALL MAPReport ParametersDate:06/12186Duration:00:10Start:09:45End:09:55MatrixFilesUsed: ITVL97.SEQ LEGEND noraintraceraino Ned.tl.ncf FIGURE2 upto0.03inchesupto0.10inchesupto0.20inchesupto0.30inchesmorethan0.30inches

PAGE 185

WARNINGSYSTEMSINTHE1985CHEYENNEFLASHFLOODJohnH.SorensenOakRidgeNational Laboratory IntroductionOverthepast20years,anaverage of163peoplehavedied in flood events intheUnitedStates(NaturalHazardObserver, 1986).Thesehaveprimarilyresultedfromflashflooding.Theyear1985proved tobenoexception;166peoplelosttheirlives.Despite a decade of experience since thecatastrophicBigThompson,Colorado, flood,yearlyfatalitieshavenot decreasedsignificantly.Duringthisperiod, our understanding ofhumanresponse to warningshasincreasedgreatly(Perryetal.,1981; MiletiandSorensen, 1986).Evenwiththisincrease inknowledgeandimprovedwarning technology,fatalitiescontinuetooccur.Thepurpose ofthisresearchisto analyzethewarningeffortsinthe1985Cheyenne,Wyoming,flood inwhich11personsweredirectvictims oftheflashflooding. Early reportsattributedthesefatalitiesto a poor warningeffortinwhicha tornado warningwasissuedjustpriorto aflashflood warning.Asaresult,thisresearch sought toidentifythewarning procedures implementedandtoinvestigatetherolethatthe warning played incontributingto thefatalities.WarningContentandDisseminationAugust1, 1985,beganasa typicalsummerdayin Cheyenne. Peoplelisteningtotheweatherforecastsfor thedayheardthatitwouldbecomepartlycloudy intheafternoon with widelyscatteredthunderstorms, possibly with highwindsandhail.Thechance of rainwas20%.Asthe evening hoursarrived,itwouldbecomecloudyandthechance of thundershowerswouldincrease to50%.Thisforecastwasreaffirmedat12:50P.M.whenthe NationalWeatherService(NWS)issued a Severe ThunderstormWatchwhichwasineffectuntil8:00P.M.Warninginformationandrecommendedprotectiveactionswereissuedbythe National Weather Servicefortheremainder oftheday. This informationwastransmitted to the publicfromtheNWS

PAGE 186

Sorensen175inthreeways.First,itwentout over weather wireteletypetothemediaforgeneral broadcast. Second,itwasbroadcast overNOAAweather radio. Third,allwarningswererelayedtotheCheyenneCivil Defensebya911telephonecall.TheCivil Defense then disseminates the information over cabletelevisionusinganinterruptsystemwhichreaches about 20,000homesin Cheyenne, overMUZAK,acommercial musicservicewhichisbroadcasted in about100commercialandofficebuildings in Cheyenne,andover theEmergencyBroadcastSystem(EBS)radio.Asthe storm developed, standardizedNWSinformationwentout to the publicalertingthemtopossiblehigh winds, hailandheavyrains,andadvisingthemtolistenforfurtherinformation.At6:20P.M.,thesituationwasupgraded to a Severe ThunderstormWarningindicatingthatthe stormhadhit.Peoplewereadvisedtoseek reinforcedshelterandtolistenformoreinformation.At7:20 aTornadoWarningwasissuedduetoasightingwest of town. wereadvisedtogotoa basementshelterorinteriorroomandtoabandon carsandmobilehomesif"inthe path" of thetornado.At7:40thepublicwastoldthatthe tornadohastouchedgroundandto pre paretotake cover.At7:50thepositionof the tornadowasconfirmed.Atthistime theNWSissued thefirstinformationtothe public about thepossibilityof "minor flooding."At7:55theCivil Defensesirensweresoundedtoalertthe public of the tornado.Theycontinued for20to30minutes.Tornadowarningswerebroadcastoncabletelevisionoverride,MUZAK,andEBSradio as wellasotherradiostations.Ataboutthesametime (7:48 P.M.), theNWSreceived a reportfroma weather observer in WesternHillsof 3.5 inches ofrain.Thiswasthefirstindicationthattheamountof rainfallingmaylead to severe flooding. MinuteslatertheNWSreceived radioreportsof floodingonDryCreek.Asaresult,they issued a Flash FloodWarningat8:00P.M.andadvised people to seek high ground. CarsandtruckswerereportedtobefloatingdownDryCreek. After receiving acalloverthe911lineat8:00P.M.fromtheNWS,the Civil Defense issued the flash flood warningoncabletelevisionoverride,MUZAK,and EBS radio.Warningmessages began reaching the general publicby8:05P.M.At8:35P.M.theseverityofthesituationwasconfirmed.TheNWSdescribed the stormasbeing extremely dangerous,andreported extensive flash flooding. Peoplewereadvised togotohigh groundandtostay indoors. Drivingwasdescribedasdangerous.TheheadoftheCheyenneNWSOffice broad castedthisinformationdirectlyoveroneof the

PAGE 187

176CHEYENNEFLASHFLOODlocalradiostations.Other local radiostationsaswellastheDenvertelevisionstationsannouncedthewarningandvarious severe weather statementswhichupdatedthewarning.At9:00P.M.,theNWSissued another Severe ThunderstormWarninguntil10:00P.M.tellingpeople creekswerefloodingandnottodrive.At9:40P.M.,anewthreatdevelopedwhenadamwest oftownonCrowCreekwasreportedtobein danger ofcollapsing.This prompted another Flash FloodWarningat10:00P.M.Extensive floodingandcarsin high water cloggingintersectionswerereported.Throughouttheremainder ofthenight peopleweretoldtobealertformorefloodingandtoremaininside.At12midnightthewarningwasextendeduntil4:00A.M.,althoughprecipitationhadended.At3:55A.M.,itwasannouncedthatthewarningwouldendat4:00A.M.;shortlythereafterthefirstreportsofpossiblefatalitieswereissuedtothepublic.Institutional War'nings ActivitiesNational Weather ServiceThemanifestationoftwodiscretehazardous eventsfromthesamestormpresentedtheNWSandlocal emergencyorganizationswith several real problems.TheNWSwasmuchmoreconcerned withthetornadosituationasseveral yearsearliera tornado devastated alargeareaonthenorthsideofthecity.Flash flooding,ontheotherhand,wasnotviewedasalargeproblem in Cheyenne.Asaresulttheforecastersweremuchmorealertfordetectingandwarningofa tornado than a flood. Flash flood guidanceforthedayreceivedfromtheNWSKansasCity Officecalledfor amaximum2.7 inches ofrain.Thisisnotgenerallya levelthatwouldcause a concernforapotentialfloodthreat.At8:00P.M.,whenflooding begantooccur, only1.5inches of rainhadfallenattheairport,whichwasnotenough to predictthatmajor floodingwouldoccur.Thefirstindicatorof aflashfloodpotentialwasthe weatherobserver'sreport,whichoccurred almost simultaneously withthelanding of the tornado.Anautomated upstreamraingaugewouldhavepro videdsomeadditionalwarning time. Aslightlyearlierindicationof major floodingwouldhave allowedmorecoordinationforissuinga dual hazard warning and,thus,avoidedtheconfusing information dissemination process.TheNWS,despitetheconfusing circumstances, acted quicklytochangethewarningfroma tornadotoaflashflood.Their redundant communications insuredthatthemessagewentdirectlyandrapidlytolocal emergencyofficials.

PAGE 188

Sorensen177Local Emergency Organizations LiketheNWS,thelocalCivilDefense,policeandsheriffoffice'swere not gearedforflashflood warnings. They,too,weremoreconcerned about thepossibletornadothreat.Furthermore,themajor flooding problemshadcomefromoverbankingonCrowCreekandnotflashfloodsonDryCreek. When a flood has occurredonCrowCreek,theCivil Defensehadagoodunderstanding ofhowtorespond, givenpastexperiences.Noplan or understandingexistedabouthowtorespondtoa floodonDryCreek.WhentheNWScalledintheflashflood warning,theCivil Defense acted quicklytochangethemessagesthatweredisseminatedtothepublic.Notimewasspentondeciding whether or nottogowiththenewwarningdespitetheradicallydifferentprotectiveactionsrequired.Whencommunications werelost,theinitialwarningshadbeen disseminatedbymedia.Noattempts weremadebylawenforcement agenciesafterbeingnotifiedofthefloodtowarnthepublic intheDryCreek area with loudspeakers orgodoor-to-door.Aswaters roseonCrowCreekthepoliceassistedin evacuatingresidentsof low-lying areas withoutdifficulties.Shortlyaftergettingtheinitialflood warningout,waterbegantoleakintotheEmergencyOperations Center(EOC).Workerssealedthedoors the best they could usingblankets. 8:30 P.M., waterwasankle deepinsidetheEOCbut 4ft.highoutsidethedoors.At8:45 waterfromthesewer begantofillthegeneratorroom.AdecisionwasmadequicklytoevacuatetheEOCduetofearofelectrocution.Atg:OOP.M.,theEOCwasclosedandoperationsweremovedtotheCounty Commissioners'Offices.Since radioswouldnotworkout ofthisoffice,a mobile communicationsvanwassetupoutsideandcommunicationswerereestablished. A shorttimelater(9:45-10:00),thetransformerinthepolicebuildingfailedandtheEOCwasforcedtoevacuate because ofthelossof power. Communications were notreestablisheduntilmidnight. Thisseriesoffailuresandrelocation had twoimportanteffectsontheissuanceofwarnings.Themajor impactwasthatitrefocusedtheattentionoftheCivil Defensefromtheexternalproblems of the floodingtomaintainingtheirowninternalcapabilities. As aresult,theCivil Defense spenttheirtime attemptingtorestoreoperationsandcould not maintainvigilantattentiontotheflood. Second,itphysicallyremovedthemaincommunications system(911phone)forcoordinationduringanemergency. Thisremovedthecapabilityforcentralcommandandi nformat ionexchange. Informat ionfrom1awenforcement personnelworkinginthe

PAGE 189

178CHEYENNEFLASHFLOODfieldcould notbefedbacktoanorganization or individual with a globalpictureoftheemergency. Thislikelyhamperedthedistributionof resourcesandconstrainedtheabilitytoupdate warning messagestothe public. Public Response Thereislittledoubtthatthealmost simultaneous development of dual hazardsandwarnings presentedanambiguoussituationtothepublic.Manyresidents reportedthattheywereconfusedbythesituation.SomeresidentsintheDryCreekarea apparently received warnings of the floodjustbefore being inun dated. Others learnedwhenwatercamepouringintobasementsaftertheyhadshelteredfollowingthetornado warning.Manyhadtofleequicklytoavoid therisingwaters.Somepeople seekingshelterin basementsmayhavedetected the floodingearlier'thaniftheyhadbeenupstairs.Others at risk intheirhomesheardnoflood warningsandweretrappedbyrisingwatersuntilemergency workers could rescue them.OnCrowCreek,residentsweremorealerttofloodingandreceived adequate warningtotakeprotectiveactions.Whenthetornado warningwasissued, people intrailerparks intheCrowCreekarea evacuated to a nearbycommunitycollege.Thisremovedpeoplefromsomelow-lying areasthateventuallyflooded. Followingtheflood, publiccriticismsurfaced regardinghowsomebusinessandcommercial organizations handled the warning dissemination. People instores,mallsandmovietheaterscomplained of not receiving warningsofthe tornado, the flood, or both. This lack of warninglikelycontributedtosomefatalities.This paucity of actionwasnotuniversal.Onestore,for example, reportedly lockeditsdoorsuntilthenature ofthefloodingwasestablishedandcustomers couldbenotified.TheWarningSystemandFatalitiesEleven personsdrownedin theAugust1stflood.Ofthese,tenwereautomobile-related (Table1).Anearlyrumorsuggestedthatpeopledrownedbecause of the confusing warningswhichfirsttoldpeople toshelterintheirbasementsandthentoseek high ground.Onlyonevictim possibly died becauseofbasementsheltering.Inthiscase, the evidenceisinconclusive.Thevictimwas

PAGE 190

Sorensen179anelderlywomanathomeandaloneatthe time.Herhousewasnot in a floodplainnor in a minor drainage system.Thebasement floodedduetoheavyoverland sheet flow.Itispossiblethatsheshelteredduetothetornado warningandwastrappedbya doorwhichstuckshut,or,alternatively,fellandcould not escape. Equallyfeasibleisthatshemayhavegonetothe basement to determineifitwasfloodingandbeentrapped orfell.Regardless ofthecause,thiscase underscores several points regardingvulnerabilitytodisaster.Oneisthatpeoplewhoare alone atthetime ofdisasteraremorevulnerable because theyhavenoonetoassistthemifthey are in danger. Second,theelderlyare oftenlessphysically abletorespondinrapid-onset and/orlife-threateningcircumstances.Asinthe Austin, Texas, flood in1981(MooreetaT.,1982)andtheBigThompson,Colorado, flood of1976(Gruntfest,1977), deathscamebecause people attemptedtotraversetheflooding stream. Table 1liststhelocationsalong a mile longsectionofDelRangewherevehicles attempted to crossDryCreek,weresweptintothe channel flow, and someoccupants drowned. At the time theywentin,the seriousness oftheflooding was notreadilyapparent.Dipsin the road overculvertcrossingsmadeitdifficultto estimate the depth of the flood waterswhichwereprobably 3to4feetover the roadhedof thecrossing,butlikelylooked lower.Mostfatalitiesoccurredbetween 10:00 and11:00P.M.whichwaslikelythetime ofpeakflood discharge.Sixof the victimswereunder 20, and,ofthese,fourwereunderten.Oneof thedeadincluded asheriff'sofficerwhowasattempting to rescue ayounggirlafterhehadsuccessfullysaved herparents.Heandthechildweresweptawaywhenthelinehewasattachedtobroke.Thenine victimswereinsixcarsandonetruck.Infour of thesesamevehicles,atotalofeightpersons survived because theywerepulled out of the waterbyrescue workers orswamtosafetybythemselves.Allwereteenagers oradults.Fromwhatsketchy evidencewehave,itseemsthatof the seven vehicles inwhichfatalitiesoccurred, onlyoneofthepartieshadlikelyreceived a strong warning message.Inthe remaining vehicles peoplemayhavereceived information over the radio while intheirvehicles but the warningwaslikelynot strong or perhapsspecificenoughtopreventthemfromtravellingacross the creektoreach asafedestination. As mentioned,someofthesepeoplehadbeenatamovieat a nearby shopping mallandreceivednoannouncement regarding the flash flood.Giventhe time of thedeaths,whichoccurredatleasttwohoursafterthefirstflashflood announcement,itisclearthatthe tornado warning playednorolein

PAGE 191

180CHEYENNEFLASHFLOODcausingthefloodfatalities.Warningmessages regardingthedangers of drivingwerebeing disseminatedasearlyas8:30P.M.Eitherthisinformation did not reachsomepeoplewhoweredriving orwasunsuccessfulinpreventingthemfromengaging inwhatprovedtobemaladaptive behaviors. ComparisionWiththeBigThompsonFloodTheCheyenneexperiencewassimilarinmanyrespects tothatoftheBigThompsonflood butdifferentinothers.Inbothinstances,floodswererare eventsandhadnotbeenexperiencedbymanyatrisk.Inbothcases,the warningcamelateinthestage oftheevent;manyreceivedno"official"warning butwerealertedinsteadbysuddenlyrisingwater.Inbothevents,somepeopleunderestimatedthegravity ofthesituation.ThefloodsdifferedinthattheBigThompsonwasamoresevere flood, having amuchgreaterflowvolumeandvelocity.TheBigThompsonflood also occurred in a narrow canyon, whiletheCheyennefloodwasin a low-flow creek bed.Theformer event impacted peoplelivingor vacationingin thecanyonwhile thelatteroccurred in aresidentialandcommercial area of thecity.Thefloodsweres imil ar with respecttovictimization.Inboth events, peoplewhosought higher groundwhenthe watershitsurvived.Inboth events, people died intheirautomobiles.AtBigThompsonmanywereattemptingtoeva cuate.AtCheyenne,manywerejustattemptingtodrivehome.Inboth cases, ignorance of the floodseverity,thelack of warningsandthelack ofspecificwarning information contributedtothedeathsbyautomobile.AtBigThompson,fatalitiesoccurred because peoplefailedtoleavestructuresor didsotoolateandweresweptaway.This did nothappenatCheyenne.Thedifferenceislikelyattributableto thedifferenceinseverityandspeed of onset oftheflood watersandland use.FewstructuresinCheyennewereinthefloodwayandfewsustainedheavystructuraldamage.Whenwater floodedbuildings,peoplewereabletoescape without going throughthehighvelocityflows. ImplicationsTheexperienceatCheyenneandthecomparisiontotheBigThompsonevent point out several lessons for improving flood warning systems.First,Cheyenne

PAGE 192

Sorensen181illustratesthedifficultyin warning the public oftwohazards occurring at almostthesamepoint in time. Thiswasfurthercomplicatedbytheradicallydifferentnature ofprotectiveactionsdesirableforfloodsandtornados.Atthe time oftheincident,noguidance inNWSoperating proceduresexistedonhowtohandlethesituation.Inretrospect,theNWSpersonnelwerequick toadjustandget the flood warnings out. Their messages couldhavebeenimproved, however,bytellingpeoplewhythetornadowasnolonger a problemandthen proceededtofocusthepublic'sattentiononflooding. Guidanceonhandling concurrent eventsandcloselyspaced subsequentthreateningeventswouldbeof use infuturesituations.Second,thisstudy reconfirmstheproblem of warning peoplewhoare notathomeatthetime ofanemergency.IntheCheyennecase,itwasprimarily movie goersandshoppers.At Big Thompson,itwascampers.Waysinwhichsuch populationscanbealertedandgiven adequate warning information needsfurtherattention.Third,thisstudyshowsthatwhile the problem of vehicles inflashfloods areknownfromeventsliketheBigThompson,solutionstothe problemhavenotbeenfullydevelopedandimplemented. General types of public informationonhazards are notlikelytobethesolutionbecauseflashfloods are infrequent eventsandoften inlocationswherethe publicdoesnot perceive arisk.Fourth, the experienceatCheyenneshowsthatwhile progresshasbeenmadein improvingwarning messages, they arestillnotaseffectiveasthey could be.Moreforcefulandinformative statements couldhavebeenmade.This finding suggeststhattheNWSshould reviewtheirstandardized warning statements inlightof currentknowledgeabout messageeffectiveness.Fifth,theexperiences of theCheyenneflood point outthedesirabilityofandneedfor redundant communicationsandcoordinationscapabilitiesin a warning system.Inthiscase,removalofcentralcommunicationsalsoremovedcentralizedleadership.Thiscontributedtothedifficultiesexperienced with maintaining a warning duringthepeakflooding. Stepstoinsure adequatebackupcommunications shouldbetakenbystateandlocalemergencyorganizations.Sixth,while plansmaynotbehighly useful insomeemergencies, the lack of planningforaflashfloodwasevident in bothdisasters.Theexperience of going through a planning process for floods couldhavereduced theamountof time requiredtolearnwhatwasneededtobedoneandbywhom.Evenwithcommunications problems, planningwouldhaveenabled individual organizationstofunctionmoreefficientlyontheirownanddelivermoreeffectivewarnings.

PAGE 193

182ReferencesCHEYENNEFLASHFLOODGruntfest,E.1977"WhatPeopleDidDuringtheBigThompsonFlood."Natural Hazard Working PaperNo.32.,Boulder:InstituteofBehavioralSciences,UniversityofColorado.Mi1eti,D.andJ.Sorensen 1986 "Natural HazardsandPrecautionary Behavior."InN. Wei nstein,Ed.Taking Care: Why People TakePrecautions.Cambridge: CambridgeUniversityPress.Moore,W.,E.Cook, R. Gooch,i1ndC.Nordin 1982TheAustin Texas FloodofMay24-25, 1981. Washington, DC: NationalAcademyPress.InstituteofBehavioralScience1986"TheNumbersTelltheStory."Natural Hazards Observer (May),p.13. Boulder: Natural HazardsInformationCenter,UniversityofColorado.Perry,R.,M.Lindell,andM,Greene. 1981 Evacuation PlanningInEmergency Management.Lexington,MA:LexingtonPress.

PAGE 194

Table 1 InformationOnFloodVictimsNo.AgeSexTimeof Activity locationDay73F?Inbasement; reason400 W 7thunknownAve233M 10:45RescueworkRidgeRoad318M10toGoinghomefromRidgeRoad10:30movie416F10toGoinghomefromRidgeRoad10:30movie(with3)56 F 10:45Invanwith parentsRidgeRoad67F 10:15 RidinghomefromRidgeRoadmoviewith parents 717F Probably drivinghomeRidgeRoad8 3F10:30 RidinghomewithRidgeRoadparent g59M 10:45 Oriving truckWindmill1027F 10:40 DrivinghomeMountain115 M 10:40 RidinghomewithMountainparent (10)

PAGE 195

MINNESOTANETWORKFORDISASTERSTRESSINTERVENTIONJosephHuberAmericanRedCrossSt.PaulandMinneapolis ChaptersWhenmental health services are provided inanyorganized sense, they are usuallysetupafteraparticulardisasterhasoccurred. Thismeansthatservicesarerelativelyunplannedandcanbeexpected to leave outpartsessentialtoa well roundedservice.TheMinnesotaNetworkfor DisasterStressIntervention(MNDSI)isanattempttoproduce apracticalplan for the delivery of mental health services during the timeofdisaster.TheNetworkNearlytwoyears ago, aGalaxyAirlinecharterflightfromtheTwinCitiestoReno,Nevada,crashedontake-offfromReno.Allbutonepassengerwerekilled.Therewereminimalmental health services providedatthe time of the incident for familyandfriendslivingin theTwinCitiesarea. Sixmonthslater,manydifferentgroups independently thought ofhowto provide the neededservicesfor the survivors ofthiscrashandfordisastersin general.Intheirdiscussions,these groups discovered eachotherandmetinJuly,1985.MNDSIwasanideawhosetimehadcome.Themission statement agreeduponatthefirstmeeting in July of1985statedthatthe purpose ofMNDSIwouldbeto "develop a service systemandcoordinated network for the prevention,earlyidentification,andtreatment of psychological problems subsequent todisaster.Thisisintended to serve victims, survivors,disasterworkers,andtheirfamilies."Eventhoughthisstatementwaswrittenabout a year ago,newimplications forservicearestillsurfacingandthe group continuestoupdateandexpandthe plan.Thekindandextent ofservicesbeing planned aremuchlargerthan ever envisionedatthestart.TheoriginalplancalledforMNDSIto serve theTwinCitiesMetropolitan Area. This includes thetwocore counties ofHennepinandRamsey,containing the majorcitiesof Minneapolis, St. Paul,andBloomington,andfive countiesthatsurround the core counties:Anoka,Washington, Dakota, ScottandCarver.Theseseven countiesmakeupthetraditionalmetro area.Thetwocounties containing thestate'stwonuclearpowerplantsare also being included in theservicearea.

PAGE 196

Huber185Duringitssecond year,MNDSIhopestoexpandontheTwinCities"model"toformatruestatewide network.MNDSIwillmakeuse of the overlap of theRedCross's major regional chaptersandtheCommunityMentalHealthSystemfor the basis ofthisplan.Theoriginalconception of the mental health service systemwasthatitbepart of alargerdisasterservicedelivery system,suchasastateor regionalcivildefense system. After consideration of these systems, theRedCross, withitsdelivery system of FamilyandNursing Services,seemedamoreappropriate choice.Itisthe agencythatprovidesshelters,social servicecenters,feedingstations,andnursingstations,allplaceswheredisastervictimswouldgather. A second reason for beingpartof alarger,recognizedservicedelivery system,istheneedfor adequateandrecognizedidentification.Foraccess todisastersitesandcontrol of mental health services providers,useof the auspices of aknown disastel' agencyprovidesinstantrecognition to victimsandworkersalike.ThePlan Before theDisasterInplanning fordisasterresponse,MNDSItookmanythingsintoconsideration.Forinstance,therearemanyagencies, publicandprivate,whoare involved indisasterworkandcouldbenefitfromeducation about mental healthservices,whothey arefor,howtheywork,whereto findthem.Theseagencies include countyandlocal emergency preparedness, NationalGuard,countyandlocallawenforcement,fire,andemergency medical service personnel, coronersandfuneraldirectors.MNDSIworksasaparallelservice to theFamilyServicesandNursing Services already providedbytheRedCross.Thepre-existingserviceshavetheirownindependent operating systems,fromtheFamilyServiceandNursing Officersatthedisasterheadquartersdowntothe supervisorandworkersateachsite.Mentalhealthstaffinghasbeenaddedateach levelofthese systems,necessitatingthe inclusion ofthreesocialserviceswherethereweretwo.MNDSIismaintaining alibrarywithbooksandarticlesdealing with theeffectsofdisasteronmentalhealth.Anannotated bibliography of these resources willbemadeavailabletoallmembers.

PAGE 197

186STRESSINTERVENTIONVolunteerMentalHealthWorkersThereare several functionsthathavetobecompleted with regard to therecruitment,training,andsupervision of volunteermentalhealth workers. Screening.MNDSIdeterminedthatvolunteermentalhealth workers shouldbescreenedastotheireducationandtraining,experience incrisisanddisastercounseling, specialskills(e.g.,second language,abilitytosign),standing in the professionalcommunity,andknowledgeof professionalethics.Jobfunctionsandstandardqualificationshavebeenwrittenandsent out tomanymental health organizationsandassociations for recruitment ofdisastervolunteers. (Availableuponrequestisthe applicationandscreening form.) Training.Thetwomajor areas needing coverage in volunteertrainingare: generaldisasterorientationandfunctions,andmentalhealtheffectsandtheirtreatment for people in time ofdisaster.Manymental health workers,eventhose with extensivecrisisexperience,mayhavenever experienced adisastereither as a worker or victim.Theymayhaveonly avaguenotion ofwhatvictimsandworkers experience.Itisnot the intention ofMNDSItohavevolunteersgothrough akindof "cultureshock"whenthey are trying to provide services. Volunteersneedtobeawareofwhatitisliketoworkinanareawheretherecanbeextensivehumanandenvironmental or property destruction. Also, theneedtoknowhowtoworkwith theinter-andintra-agency operations involved inanydisasterisessential.Often, these operations appearfromthe outside tobeadisasterallbythemselves.Crisisworkersmaynotknowwhatto expect in terms ofintensityanddiversityofoutcomeofmentalhealth reactions of people during times ofdisaster.Training in disaster-causedmentalhealth problems,symptoms,courseandtreatment (shortandlong term) are part of theMNDSItrainingpackage. Also, problemsmaydifferwithdifferentclasses of people.MNDSIhassetupaworkinggroup to consult withdifferentclasses of people.MNDSIhassetupaworkinggroup to consult with representatives of special needs populations,suchaschildren,elderly,disabled,andminorities.Itistheintentof thegrouptoidentifyasmanyspecial concernsaspossible inworkingwith these higherriskpopulations.TheServiceSystemThere are four major functions forwhichvolunteermentalhealth workers willberecruited:assessing needs, coordinating services,on-sitesupervision,andonsitecounseling. This system dovetails with the currentRedCrossFamilyand

PAGE 198

Huber187Nursing Servicestructure.Followingisalistingof the job functionsandtheirduties.Needsassessment. This workermaygoout with theRedCross "windshield" surveyteamtoassess theamountofdamage,sizeandnumberofdisastersites,andestimatenumberof peopleaffected.This assessment occurs veryearlyin the recoveryfromadisaster.Theinformation gatheredisusedtodetermine thenumberandlocation ofon-siteworkers.Theneeds assessor shouldhaveexperience indirectservice,administration,anda workingknowledgeof the local mental health service system. Coordinator. This personhasthe majorresponsibilityforallmental healthactivitiesduring(andperhapsafter)thedisaster.Thecoordinator obtains informationfromthe needs assessorandRedCrossJobDirector, decideswhichlocations willbestaffed,whichworkers willbecalled,establishesa schedule for workers, providesreferralsfor ongoing servicesandcoordinates withRedCrossFamilyService, Nursing,andoutsidementalhealth agencies.Thecoordinator'squalificationsinclude being a mental health professional with experience incrisisinterventionanddirectservice,supervision,andadministration ofservices.Anextensiveknowledgeofthe localmentalhealth resourcesisessential.On-site counselor(directservice volunteer. These workershavethe responsibilityof providingdirectmental health service to victimsandemergencyworkers. Counselors shouldbemental health professionals withcrisiscounselinganddirectservice experience.Insomecases, theon-sitesupervisor or counselormayprovide outreachservicesthroughoff-sitehomevisits.A computerizedfileofallvolunteers,theirskills,jobdescription,location,andavailabilityexistswith 24-hour accessandhard copies provided toallcoordi nators. Thereisa phone-tree networksetupfor rapid access to volunteers. After aDisasterAfter thedisaster,MNDSImovesinto anewphaseofoperations amounting to a reviewofservicesatseveraldifferentlevels.Debriefing. After eachdisasterthereisanindepth debriefing of the mental healthservice.thisdebriefing thenbecomespartof the overallcritiqueofRedCross services provided during thedisaster.

PAGE 199

188STRESSINTERVENTIONCasereview.AllRedCross cases (mental healthandotherwise) are reviewed for completeness before each caseisclosed. This includes checkingonwhetherclientsacceptedreferralsandifthereferralswereappropriateandhelpful.Casereview bringsuponeproblemthatMNDSIisstillgrappling with.Itdeals with the issue ofhowtomakereferralsfor ongoing treatment servicesbeyondthecrisisintervention period of approximately three days.Mentalhealth services provided during adisasterare free of charge providedbyvolunteer professionalswhomaketheirlivelihood doing these servicesatother times.Theywill finditverydifficulttoprovided ongoing services to thosewhoneeditonthatsamefreebasis.Communityresourceswhichnormallyhavelong waitinglists,maynotbeable to handleanyoverload adisastercould create in a timely manner. Insurance companies,HMOsandMedicalAssistance (federalprogramforlowincomeclients)tend nottopayforthe treatment ofsymptomsnormally seen in adisaster(including post-traumaticstresssyndromeandadjustmentandstressreactions).Asthe free services areusedupor overbookedandthe fee-charging servicesdonotwanttopay,referralsforclientscanbecomedifficult.There are three other servicesMNDSIisconsidering providingtoRedCross volunteersandotheremergencyworkers. Preventive education. Sessions foremergencyworkers about the causes,symptomsandalleviationofstressonthe job. Debriefing. Providing personnel todebriefworkersastheycomeoffshift.EAP.Possibly providingEmployeeAssistance Program-like servicesforvolunteer workerswhowouldnothaveaccess toanEAPthroughtheiremployer.MNDSIhasalso prepared generic handoutsforthemediawhichdetailvictim information,symptomsofstressandtheneedfor appropriatecommunityresponse towarddisastervictims.Assomeof the public are verysensitiveabout being stigmatizedbythe useofmental healthservices,"stress"and"stresscounseling" are the termsusedinmediareleases.MNDSIhastrainedspokespersonswhohandle contact with the media.

PAGE 200

LESSONSFROMAUSTRALIAN WARNING EXPERIENCE John W.HandmerAustralianNationalUniversityEdmundC. MiddlesexPolytechnic inAustralia:TheLast Ten YearsThelastdecade has been afrustratingperiodforthose involve'"! in flood warnings inAustralia.Itistenyearssincea majorinquiryintothefederalBureauofMeteorology,an organisation withnational stat:ltYyfor themeteorologicalaspectsofflood warnings andwhichprovidesriverheightforecastsformanymajorstreamsineastern ia.The inquiryrecofTJfTJcnderl thattheBureau'sfloodwarningfunctionsbehandedtothestates (::[W1,197fi). But,thestatesshowedlittleenthusiasm,andintheabsenceoffirmaction I)y thefederalgovernmentthesituationhas beenuncertainever since. Theuncertaintycreatedbyindecisionhaseffectivelyreducedthe funds availablefor warningsystems.ThisisgreatlyexacerbatedbythegeneralleveloffundingavailabletotheBureau.The Bureau estimatesthatsomeAS50D,OOOisneeded immediately(ieforthe 1986-87 fiqancialyear)toreplaceandupgrade floodforecastingequi pment.To put thisrequestinperspectivethe1985-86capitalallocationtotheorganisation'sfloodwarning programwasapproximatelyA$50,OOO.Fortunately,theBureau'sfortunesmaybe about to change. ArecentreportbytheAustralianHouseof Standing CommitteeonExpenditure(1986:x)urgesthatthegovernment"endorsethe Bureau ofMeteorology'sacceleratedre-equipmentplan.The plan willenablea long overdue upgradeoftheBureau'sbasicinfrastructure".

PAGE 201

190AdministrativeArrangementsWARNINGSINAUSTRALIADespiteitscentralpositioninAustralianfloor! warning the1ureau's involvementvariesgreatlybetweenstatesandterritories.IngeneraltheBureauprovidesquantitativeandqualitativeriverheightwarnings inthefoureasternstates,andgeneralisedwarnings basedonweatherpredictionsfor WesternAustralia(WA),SouthAustralia(SA)andtheNorthernTerritory(NT).Toalargeextentthisemphasiscorrelateswell withtheextentandseverity ofi:l1e floorl problem. However, evenwithintheeasternstatesarrangementsvarygreatly.InQueensland (Qld)theBureaunotonlymakesriverheightpredictions,butdisseminatesthemtothepoliceand media as -,o/ell. Itisimportanttonotethatthefederalgovernment,throughtheBureau, pays forthisadditionalservice.OntheotherhandtheBureau'srole in Victoriaisrelativelylimiter!.AlthoughtheBureauissuesfloodwarnings for Melbourneto the:nedia itissimply pussing onforecastsgenerated hy the andMetropolitanBoarrlof '10rks (MMBW).Clearlytheinequityinservice provisionandthusresourceallocationisanimportantissue.Therolesofothercomponents inthefloorl e:nergencyservicesalsovarygreatly.GenerallytheBureauandStateE,nergencyServices(SES)issuewarningsthroughthemediaoftenincollaborationwithlocalauthorities,andtheSES a'1d policecontactthepUblicdirectly.However,thisvaries,for example i'1 NewSouth Wales(NSW)allprecise(riverheight) warni'1gs areissued by theSESfollowing ge'1eral alertsfromtheBureau. Table 1 showsthattheBureau has '10 monopoly overissuingwar'1ings, a'1d thatinsomejurisdictio'1s the disseminatio'1arrangementsinvolveamixtureoforganisations.Local or community warning systems forflashfloodingfrom urbancreeksanrlstorm sewersarepoorlydevelopedandneedattention.Aquestio'1nairesurveyof22keyprofessionals,:nainlyscientistsanr!engineers,working inAustralia'sfloodforecastingandwarning systemshelpedtoestablishtheissues.Thesurveywasundertake'1ata workshoponflood warni'1gs

PAGE 202

Table 1:Flood warningsarrangementsinAustraliaQLDACTVICTASNT Warnin9 BaM" LAsPreliminarydissenl1natlon:issuewarning warnings fromtopolice BaM tomedia .!, med1a.sESetc.DEWS. PWD. Hydromet.datacollection &.fO'"t!cast preparation:BaM &. LAs. resourcecommitmentbyBoM.BaM,SES & LAs.SES LAsfloodfunctionsoftenmerge oue tocrossappointments.Precise dict ion areallissued througrl SES. RoM&. joint1ypredictflows. Bo"1.\. toSES,Police others.Rweprovi desdatawhere it operates Coordswith flaM.MMBW opel'"atestheMelbournesystem. WhereRwe has stOl"'ages itgenerates warnings incoord with BaM. floMissues warningstopublic,media. andSES.SomeLAs provideinterpr-et fve serv1ces. MMBW 1ssueswarningstoSES BoM issuesthemtothemedia.HECprovi dessomeofthe riata to !kiM.BaM providesall !'JEWSpf"imary warningsto tothemedia.SES. Police" SESalsopass on warnings with localinterpretiveinfo.PoliceoPWDPolicetotoSES.SESAbbrevi Jt io'lsBaMBureauofMeteorologyLALocalauthoritySESState(or territory) EmergencyServiceDHCDepartmentofHousing and Construction(federal)RWCRural WaterCOllTTli ssion(Victoria)MMBWMelhourne andMetropolitanBoardof Works HECHydroElectric COllTTlission DEWSDepartmentof Engineeringi!l'i0Water Supply (SouthAustralia) PWLJ PUblic Works Department (WesternAustralia)1. Arlditional bodiesareinvolvedinNSW.TheRiver Murray Cormdssionissues flooopr'edictlor'lSfOt' thelower Murray.The Water Resources Commissionprovidesinformationfromthestoragesitoperatesandthe Snowy MountainsAuthorityprovides a localservice.2. Bo"1 istotakeovermuchoftheresponsibilityoverthenexttwoyears.inAustraliaheldatCRES,ANUFebruary,1986.ThestatesofWesternAustralia and Tasmania werenotrepresented.Resultsofthesurveyarereportedinfullin Pennin9-RowsellandHandmer(1986a).Institutional ChangeThedominantresultisthatofa mosttoimprovefloodwarnings inrespondentsidentifiedsomeformquestionaskingwhatsingleAustr aIia. Near lytwoofinstitutionalchangeactionwoulrl rio thirdsoftheasdesirable,principally:clarificationoftherolesofthemany involved;increasingtheexpertisewithintheBureau through upgradedresources;or taking

PAGE 203

192WARNINGSINAUSTRALIAresponsibi 1ityforfloodwarni ngsawayfromtheCommonwealth, accompani eoby realisticfundingtoenablethestatesandlocalgovernmenttoprovidetheservice(Table2).EvenifthislastoptionwasimplementeditshouldberealisedthattheBureau wouldsti11 he involvedinfloodwarningsthroughitsmeteorologicalfunction.Table2:Analysisofthenominated'singleaction'toimprovethefloodwarningsituationinAustralia.ACTION1.INSTITUTIONAL/FUNDINGe.g.ClarifyinstitutionalarrangementsClarifytheroleoftheBureauofMeteorology Passresponsibilityfrom Met. BureautoStates2.POLICYISSUESe.g.ResolvepolicyvacuumEstablishfloodwarning 3.PUBLICNEEDS/RESPONSEISSUESe.g.CommunitypreparednessPubliceducationonhazards4.OTHERISSUESPERCENTAGE58%21%16% 5% 100% u _Aquestiononthethree main issuesinfloodwarningprovided aoditil)nal detail.TheIleed forestablishedandconsistentinstitutionalarrangementswasseen asparticularlyimportantin afieldwhereoperationalefficiencycanonlybetestedrarely-duringfloodsand whereadministrativearrangementshavetobe keptintactandeffectiveformanyyearsbetween suchoccasions. Who paysforflood warningserviceswasa secondaryissuebutstillcentraltotheperceivedinstitutionaldeficiencies.Thegeneral vievlf/as thatatotallyinadequatefinancialallocationwasbeingmade to theimplementationofnewtechnologytoimprovethefloodforecastingservice. Other importantissuesconcern theneeo forbetterwarningdisseminationand pUblicpreparedness.Althoughthesepointswerenotseen asimportantastheinstitutional/policy iss
PAGE 204

Handmer193Whentheinstitutionalissuewaspolarisedintothetechnicalversustheinstitutionallimitationstoeffectivefloodwarning syste'nsthelatterstilldominate.Onlythreerespondentsindicatedthatthekeyproblems weretechnicalratherthaninstitutional.Thosesuggestingthattechnicalproblemsarethemostimportanteitheremphasise t'le difficultiesintheirabilitytojustifyexpendituretotheirpoliticalmasters, and thusarereferringtoproblemsofwarning systemevaluaticl1,orstressthattechnicalexpertiseis central tooperatingafloodwarning systemandthatitmustthereforebemostimportant.Satisfacti on wit h in 9dissemi an gemen t s Therewasgeneralsatisfactionwiththewarningdi sse'nination arrangementswithinallareasofAustraliacovered,althoughreservations ,'Jere expressedandsomerespondentsweredefinitely happy theirlocalarrangements. Aho'Jttv/othirds oftherespondentsfeltthatthepresentarrangementswere "good" or "satisfactory".Themainweaknesses inthepresentsyste'ns conce"'1 th"? difficultiesexperiencedin technicalinformation fro'Tltil"? forecasterstothepublicthroughvario,]slocal anrl state govern,nent organisationssuch asthepoliceandtheStateEmergencyServices(SES). Worse, insomecasesitappearsthatlocal personnel maynotbeinvolved atall. Sometimeslocaldecision-makersare'j,);:I'eceivingthecorrectinformation, anrl thepublicmaynotknowwhatto dov/hen warned.Occasionallythismay berlue inparttothelackofBureaustaffto till' liaisonactivitiesduringfloods.Adifferentproblemoccurswhentherearecompeting floorl forecastswllere alocalindividualor groupmayi)'lilliciseadifferentexpectedfloodheight,in addii; i '1'1tothe officialforecast,thus calisin'J(I)'lfusion. Thislastproblem hasbecomerelatively -/110:11,1110'1,<11HI oneofthemainperceivedstrengthsofthepresentarrangement insome easternstatesis thatforecastsnowcomefrom oneauthority(see Table 1).Rapid communicationwasanotherpositiveaspect,butthecommunication systemisalsoa ,najorsourceofproblems duetohreakdowns.Themainsuggestionsfor j'I1!l"I)velnents focusonenhancing coorrlination betweenthevariouslevels ofgoverq,nent. Animportantadditionalpointwastheneedtoprovideeducationand infor.natioljto everyoneinvolved-notjust"thepublic".

PAGE 205

194Lega 1LiabilityWARNINGSINAUSTRALIAAnissuenotmentionedbytheintervieweesbut one which has been assumingincreasingimportanceinAustralian flo01,)lolin managementisthelegalliabilityoflocalgovernment (Handmer,1985). Somestateshave passed legislationlimitingtheliabilityoflocalgovernment forfl,),)dplain,nanagementdecisionsandforadvicegivenwith r-espect tofloods.However,the extent ofliahilityisunclearasthereisinsufficientcaselawinAustralia(Partlett,1986).But,itisquitepossiblethatoncelocalgovernments fortheoperationand maintenance! offloodwarning systemstheymaybe1 iable forlossesassociatedwithavoidablesystemfailure.LevelofTechnologyLargely because ofashortageoffundstheleveloftechnologyemployed by theAustralianBureauof islowerthanotherindustrialisedcountries.Oneneedstolook beyondthereasonable :)y weather-r-adaranduseofautomaticweatherstationstotheageandreliabilityof f'ir:ilii:ies. Forexample,thecountrynowhas25 weatherr-adar-s and a small networ-k ofoffshoreautomatic weatherstations,butmuchofthisequipmentisobsolete,unreliableanddue forreplacement (Table 3).Notone r-adar isdigitisedsothatthedataitcollectscanbetransferredelectronically.Table3:Locationandageofweatherradars inAustralid.'\ge in ye,il's is in brackets(Button,1986).DampierGoveTownsvi11e-Ai rportCarn arvonLearmonthBroome Mt Kanighan(new)(n (new)(2)(7)(10)(11)GladstoneTownsville-MtStuart t1ackay Darwin Sri sbanePortHedlandColirn s(13)(14) (14) (17)( 17) (18) (23) ___________u un_nnnn _However, viewednationallythepictureisnotas badandisimproving.TheMelbourneandMetropolitanBoardofWorksrunsasophisticatedfloodwarning system forthecityofMelbourne(some3millionpeople)where warning timesare

PAGE 206

Handmer 195veryshort,thefederal90vernmentrecently announced thatitwouldmake 'lloney availableforlocalfloodwarningsystems,somelocalgovernmentsare tal:i,]Jthe initiative,andsatelliteimageryiswidelyemployed.Mostrespondentsfeltthattechnologyhad sofarhad onlyinfluence onfloodwarnings in Australia,althoughsome stressed thattherewaspotentialforperformance andpointedtominor improvements(Table4).Interestingly,theseviews werenot, on thewhole, based onsystematicassessment,implyingalackofrigorousevaluationof potential for investmentinnewtechnology.Also,itwas t!le 'ninoroperational improvementsObtainedhad been translatedintoimprovements in publicresponse.Theexceptions were tworespondents whot'lili; i;",chnology had rec",ntly madeverylargecontributionsto improviilJf1,)')'!"idrnings. Bothofthesepeople involvedinareas with veryshort 'warning leadtimes: one hadrecently adarnbreakwarning system(Linforth,1986), and theotherisconcerned with urbancatchmentswheretimesofconcentrationareintheorderof 2-4 hours(Geise,nan,1986).Here"insomecaseswarningsare now possiblewheretheyweren'tbefore".Theseexceptionsthereforehighlightthe logicalilpplication ofhightechnologytoareaswhererealtimedataareessentialtoprovidingaforecast.Bothcasesreceivefunds from urban authorities. Table 4:Effectof new technologyontheoverallperformanceofflood warni<1g systems -----.-.--._---_..-----------Respoll Systematicevaluationmadeoftechnology'seffectsYesNoNone/verylittle5 2 3Little/buthaspotential413Improvement(but qua Iified)4 4Moderate** 1 1Greatimprovement2#2*DonItknow3*#**RepresentingthefactthatwarningisnowpossiblewhereitwasnotpreviouslyBothcasesofshortwarningleadtimes hadnooperationalfieldexperience

PAGE 207

196WARNINGSINAUSTRALIA We emphasisethatthelevelofappliedtechnologydoesnotreflectbadlyontheBureau.Theysimply have nothadtheresources.But,theyaredevelopinghardware for improved communication betweenfieldobserversandcentralcomputers andotherequipment. We needtoconsidertheextenttowhichtheapplicationofnew wi11improve warningeffectiveness of reduceE flooddamages (Penning-RowsellandHandmer, 19B6b). This theimportanceofestablishingthecost-effectivenessofwarning systemsandofputtingresourcesintoimproving warningdisseminationandco'n,nunitypreparedness.Concl usion Although knowledge inmanyareasoffloodforecastingand 'ViS expanded inthelastdecade,indeedtheavailabletechnologyisvastlyimproved, problemsremain.ThemainlessonfromAustralianexperienceisthattheseproblemsaredominantlyofaninstitutionalnature.Theyconcernallocationofresponsibility,improvementstointer-agencyco:n'nunication, mechanisms forfunding,andthepossibilityoflegalliabilityassociatedwithlocalwarningsystems.Resolutionoftheseproblemsandconsequent improvementtowarning syste,n effectivenessdependsonpoliticaldecisionsconcerningtheallocationofresponsibilityandresources,improved communicationand coo r rli'1dtio'i emergencyserviceagencies,andclarificationofthelegalposition.Thismayrequiresomestatutorylimitationoflocalgovernmentliability,asisalreadythecaseforfloodplainmanagement insomestates,and restructuring oftheemergencyserviceagencies.Lackofavailabletechnologyisnota major problem,andapartfromcasesofshortleadtime such asdamfailuresandfloodingfrom urbancreeks, t'le applicationofnewtechnologyisnotexpectedtomakemuchdifferencetofloodwarningsapartfrom improvingreliability. ;Iethods forassessingfloodwarningeffectivenessin termsofflooddamagereductionwouldassistthefundingprocess.Without doubt improvementsareneededtowarningdisseminationandpublicpreparedness,butheretheprimary needistofindwaysofapplyingexistingsocialscienceknowledge.

PAGE 208

Handmer197 This perhaps is howourunderstandln9ofmiti9ationhas changed.Effectivefloodwarningsrequirenotonlyappropriatetechnology and individualand communitypreparednesshutalsoa workableinstitutionalframework.TheauthorsthanktheUSNationalScienceFoundation for funding John Handmer'sparticipationinthisconference.References -----AustralianHouseofRepresentativesStandingCommittee on Expenditure1986Gone thewinds(Inquiry into'1eteorological Services).Canberra: na"lia'ne'1t oftheCommonwealthof Austrilliil. Button,J.1986"SenatorButtontabledinformation ontheBureau ofMeteorology".Hansard.Senate19February:656-657. CIBM (CommitteeofInquiryintotheBureauofMeteorology) 1976 ReportoftheCommittee. Canberra:AGPS.Gieseman,M.1986 "11elbour"e's floodwarning system" in Smith,0.1.&Handmer, J.W.(eds).Flood __inAustralia:. pr)licies and technology.Canberra:CRES,ANU.Handmer, J."i. 1985 "Floodpolicy ,'eversal 9(4):279-285.inNewSouth Wales,Australia".1isasters -----Linforth,S.1986 "Developmentofadambreak warning Sj5te.n" inS:nith, ILl. & Handmer, J.W.(eds).Flood ngi'1 _...:.i'-',.n itutions,policies and technology.Canberra: eRES, ANU. Part1ett, '). F 1986 __ of (Draft):CRES,ANU.Canberratheconceptual,Canberra:CREs,Penning-Rowsell,E.C.&Handmer, J.W. 1986a Flood .forecasting ... __ .__Australia:a SUrV'ly ofinstitutions and policies.Canberra:CRES,ANU(WorkingPaper).Penning-Rowsell,E.C.&Handmer, J.W. 1986bEvaluatingfloodwarningeffectiveness: melhod_o_l Og1ca 1--iiiia-pract1 caI -reseaC.c.h prob 1 em:ANU(Working Paper1986/6).

PAGE 209

THESOCIALIMPACTSOFDISASTERHAPPENINGSANDEMERGENCYSITUATIONSC.NelsonHostetterMennonite Disaster ServiceMuchhasbeenresearched, studied,andthenwrittenbythe academicandscholasticworldontheBigThompsonCanyonfloodandthe generaldisasterandemergencyfields.Thepractitionershavebenefited togreaterandlesserdegrees, dependentonthepracticalityof the research, theefforttounderstand theresultsof thestudies,andthetransferof knowledge, also basedupontheinterestandthe level ofapplicationbythose organizationsandpersonswhooperateandrespondafterthefact.Attentiontothe needs of the adversely affectedindividuals,families,andsufferingcommunitiesmustbeaddressedcarefullyandcomprehensivelybythe helping agenciesanddedicated personnel.Asanorganization, MennoniteDisasterService(MDS)wasinvolvedatBigThompsonforthreedaysafterthe flood, inprivateproperty cleanup,anduptoa yearandahalfofrepairsandreconstructionforhomesdamagedor destroyedbythesurprisestormandsubsequent flood.visitedourprojectandwith the cooperating agenciesonaquarterlybasisduringthattime.Ingeneral, Iwouldsummarizethe recovery operationsbygovernmental programs-federal,state,countyandmunicipal--voluntary agencies suchasAmericanRedCrossandadhoccommunityorganizations,andreligiousgroupssuchasSalvationArmy,ChurchWorldService National Programs, localinterfaithanddenominational programs,allin concertandasatotalteamtaking care of thesituationwith the approvedandavailablebenefitsandresources,asanaboveaverage accomplishment.Theindividualdisastervictim'sneedsmustbegivenattentionatthe individuallevel.Caseworkers should counsel in acareful,butdirectconference.Theneeds offamilies,whenthecircleissmall orlarger,mustbeadequately coveredafteranevaluation oftheirimmediateloss,theircurrentresources,andtheirfuturelong-rangebenefitsareallput together in a comprehensive packageandthenassistanceandhelp shouldbearranged.AllowmetostatetheextradimensionthatMDSaddsintryingtorebuild ahome,andnotjusta house.Thesufferingcommunities should receive consideration for publicassistancebasedontotalloss versus theratioof population affected in the micro ormacrosituation,theincomestatusandwealth percapitaof the affectedcommunity,andthe solvency/insolvency

PAGE 210

Hostetter199ratioofthelocal,state,andfederal governments.Ofcourse,weareallawareof thefinancialsituationof the federal government,andare appalledattimeswhenthetwosenatorsanddistrictcongressmemberandtheirstaffspromise the "rainbow" to thesufferingcommunities, or ask for"porkbarrel" programsandbenefits.MDShasfocuseditsrecoveryeffortsonprivateproperty cleanup, temporaryandpermanentrepairsfor theelderlyandunderinsured,andreconstruction forlowincomevictims, disadvantagedminorities,andthe handicapped.Wehavealsomadeanefforttotrainour long-term leadersandvolunteers,andorientshort-termandrotatingworkers to understand personal emotional traumaandstress,tocopewith familystrainandtenuousrelationships,andperceiveanynegativedynamicsandcounter-dynamics within thecommunity,aswellaspositivecommunicationpossibilities.Allowmetoaddtothisdiscussionthatona regionalbasis,MDShasbeeninvolvedandisavailabletodisasterareasandprograms forcrisiscounselingandmentalhealth support through10MennoniteMentalHealth Service Centers inCanadaandthe UnitedStatesTheservanthoodofMDSismotivatedbyreligiousconcernandso,aspersons with convictionandasanorganization with thebeliefthatweshouldimprovethisgoodworld whileweare privileged tolivehere,wealsohavearesponsibilityfor presentingspiritualissuesandvalues.Weassistfirstbecause of a need,andourinterestinservice,andweare cautious nottoconvert orproselytize.However,aswestaylonger in acommunityandhavethe opportunitytoworkandservedirectlywith individualsandfamilies,wecancommunicateourcommonhopefortheirbettertotallivesandthe rebuilding ofcommunity.

PAGE 211

ThispageISblank

PAGE 212

PARTFIVEHYDROLOGYANDGEOMORPHOLOGY

PAGE 213

ThispageISblank

PAGE 214

HYDRDLOGICRESEARCHRELATEDTOTHE1976BIGTHOMPSONRIVERFLOOD,COLORADORobertD.JarrettU.S.Geological SurveyAbstractAmultidisciplinarystudy ofprecipitationandstreamflow recordsandpaleofloodstudiesofchannelfeatureswasmadetoanalyzetheflood hydrologyoffoothillandmountain streamsintheFrontRangeofColorado, because conventionalflood-frequencyanalysesdonotadequatelycharacterizetheflood hydrology. Inthefoothillsof Colorado, annual peak flowsarecausedbysnowmeltathigherelevationsinthemountainregions,byrainfallatlowerelevationsintheplainsandplateauregions,orbya combination ofrainfallingonsnow.Aboveanelevationofabout 7,500feet(whichvariesslightlywith major riverbasin),snowmeltratherthanraincontributestothefloodpotential.Regional flood-frequency methods, supportedbypaleoflooddata,were developedthatindicatedthe1976BigThompsonRiver flood has arecurrenceintervalofatleast10,000years.IntroductionMorethanthree-fourthsofColorado'spopulationisconcentratedalongornearfoothillsatthebaseofhigh mountains.Manyfoothillstreams flow throughsceniccanyonsbeforeflowing ontoflatplainsorplateaus.Because oftheestheticsetting,developmentisincreasingrapidlyinthesecanyonareas.However,foothillstreamsaresubjecttofrequentandcommonlydestructivefloods.Foothillstreams flood as aresultofbothexcessivesnowmeltandrainfall;historically,themostdestructivefloodingresultsfrom"cloudburst-type"rainfallassociatedwithseverethunderstorms duringthespringandsummer.Techniques usedtodetermine floodcharacteristicsforfoothillstreamsareinadequateorunverified;thus,vastlydifferingresultscanbeobtainedfromdifferenttechniquesofanalysesusingthesameflood record. Becausesomefloodsresultfrom

PAGE 215

204HYDROLOGICRESEARCHsnowmeltathigherelevations,whereasothersresultfromintenserainfallatlowerelevations,availableflood recordsforfoothillstreamsareapplicableonlytothespecificcollectionsiteortonearbysitesonthesamestream.Asaresultoftheseproblemsandthepotentiallyseriousconsequences, a comprehensive,multidisciplinaryprojectwasundertakentoevalutetheflood hydrologyoffoothillstreamsinColorado(McCainand Ebling, 1979).OnJuly31, 1976,theneedfora studyofthistypewasdramaticallyreinforcedbytheoccurrence ofthedevastatingBigThompsonflood alongtheFrontRangefoothills(McCainandothers,1979).Asmuchas12inches ofrainfellonabout60square miles ofthedrainagearea.Thefloodlastedonly afewhours;but,duringthattime,itcausedthelossof139lives,andpropertydamageestimatedat$35million.This paper providesanoverview ofmultidisciplinarystudiesof flood hydrology conductedbytheU.S.Geological Survey, whichrelatetothe1976BigThompsonRiverflood.This comprehensive study of streamsinthefoothillsregionof Colorado concentratedon: (1)Ananalysisofavailablestreamflowandprecipitationdata,(2)theuseofpaleohydrologictechniquesinflood-hydrologystudies,and(3)floodinformation-transfertechniques.Amultidisciplinarystudy,inwhichtheanalysisofavailablestreamflowandprecipitationdataiscomplemented with geomorphicandstratigraphictechniquescommonlycan answerquestionsabouttheflood hydrology of a nearbyareathathaslittleavailablehydrologicdata;generally,studieslimitedtoasingledisciplinecannot providetheseanswers. AnalysisofStreamflow DataTypically,recordsfromstreamflow-gagingstationshave been usedtoderiveflood-frequencycharacteristicsforgagedsites.Thepredominant computationtechniqueistofitthelog-PearsonType-IIIfrequencydistribution(U.S.InteragencyAdvisory CommitteeonWater Data, 1981)tothe observed annualfloodseries.This conventional hydrologicanalysisfailstoproperlyaccountforthemixedpopulationofrainfall-runoffandsnowmelt-runoff peakscontributingtothetotalpopulationof flood peaksinthefoothillsregion.Asaresult,thecomputedstatisticsarenot

PAGE 216

Jarrett205correctanddonotfitthedata.Therefore,peak flows needtobeseparatedaccordingtometeorological causeanda frequencyanalysismadeoneachdistribution(Crippen, 1978)toprovidemorereliablestatisticsdescribingtheoccurrenceoffloodpeaks. Streamflowrecordsof69unregulated streams intheSouthPlatteRiver,theArkansas River, andtheColorado Riverbasinswere examinedtodetermine peakdischargesfromsnowmeltandrainfallrunoffduring each wateryearof record(Elliottandothers,1982). Hydrograph shapeandweather records were usedtodeterminethemeteorologic sourceofrunoff.Snowmelt-runoff peaksresultfromtheseasonalablationof snowpackandthey appearonthehydrographs aslowpeaksthatfluctuatediurnally.Rainfall-runoffpeaksresultingfromconvective stormsorfromfrontalweather systemsaffectstreamflowmuchmorequicklyandappearonthehydrographs asrapidlyincreasing dhchilrge withrelativelysharp peaks. MethodsdescribedbytheU.S.Interagency Advisory CommitteeonWater Data (1981) were followedtodeterminethestationflood-frequencycurves,includingdevelopmentofgeneralizedskewcoefficientsfortherainfall-runoffandsnowmeltrunoffpeak-flowarrays.Ifthepeak flowsareclassifiedaccordingtometeorologicalcause,separatefrequency curvesforeach meteorological cause orpopulationcanbeconstructedanda compositeflood-frequencycurve canbecreated.Becausethesnowmelt-runoffandtherainfall-runoffflood-frequencycurvesata givenstationeachrepresentindependentpopulationsthey canbecombinedbyusingtheequation: P (composite)=P (snowmelt)+P(rainfall)-P (snowmelt) xP(rainfall),where Pistheprobabilityofoccurrence (Crippen, 1978). Flood-frequencyrelationsrepresentingsnowmelt,rainfall,andcomposite peak flowsfortwositesintheBigThompsonRiverbasinareshowninfigures1and2.Inspectionoftheplottedrainfalland snowmeltflood-frequencycurvesindicateswhichmeteorologicalcause predominatesatastation.Thefollowing comparisonbetween a high-andalow-elevationstreamflow-gagingstationhelps demonstrate

PAGE 217

206HYDROLOGICRESEARCH5000 100 L __ 0.50 0.200.100.050.01 0.001EXCEEDANCE PROBABILITYFigure 1. Flood-frequency curvesforBigThompsonRiveratEstes Park, Colorado.thatthechangefromsnowmelt-torainfall-dominatedfloodingisabruptover a 2,200feetrange ofelevationin about15miles(thisdistancewould varybybasin).Thehigherelevation(7,500feet)BigThompsonRiver streamflow-gagingstationatEstes Park(fig.1),with a drainageareaof137squaremiles,isa snowmelt-dominated stream with peak flows(runoffpredominates) well in excessofthe100-year(0.01probability)flood.Incontrast,thelowerelevation(5,300feet)BigThompsonRiver streamflow-gagingstationatthemouthofa canyon near Drake(fig.2),with a drainageareaof305squaremiles,isarainfall-dominatedstream with peak flowsinexcessofthe2-yearflood (0.50probability)anda snowmelt-dominated stream onlyforpeak flowslessthanthe2-year(0.50probability)flood.

PAGE 218

Jarrett o zo lrlVIffi"-I;; 10,000Uiii :> u <; ui 5000 :I: U VIis'"..100g.'=80,---'-------'---O::-!,:::-O--'--L---;;O-'o20,-------,.'01"'O-----,O;;-';;O.,--, EXCEEDANCEPROBABILITYFigure2,Flood-frequency curvesforBigThompsonRiveratmouthofcanyon, near Drake, Colorado.207Similarcomparisons weremadeforall69stations;thesecomparisonsindicatethatsnowmeltrunoffdominates aboveanelevationofabout 7,500feet(elevationvariesslightlywith majorriverbasin).Abovethiselevation,rainfallgenerallydoes notcontributetofloods having arecurrenceintervaloflessthan100years(0.01probabilityofoccurrence).Belowabout 7,500feet,rainfall-producedpeak flows predominate. StreamflowdatafromtheSouthPlatteRiverbasinintheColorado FrontRange(oneareaofthefoothillstudyregion)indicatethatsnowmelt floods predominate above 7,500feet.Thiselevationlimitvariesslightlybymajorriverbasin.Whererainfalldoescontributetofloods above about 7,500feet,dischargesperunitdrainageareaareextremelysmall,compared withlower-elevationfloodsresulting

PAGE 219

208HYDROLOGICRESEARCHfromrainfall.Inbasinsabove 7,500feet,largefloodsinitiallyattributedtointenserainfall,thatwereinvestigatedandusedinrainfall-runoff-derivedfloodhydrologystudies,were,infact,debrisflows (whicharecommonlycausedbysnowmeltorlowtomoderaterainfall)and notwaterfloods(Costa andJarrett,1981). Adebrisflowisagravity-inducedrapidmassmovementofabodyofgranularsolids,water,andair.DebristypicallycO;lstitutes70%to80%ormore,byweight, oftheflow.Useofdebris-flowdatain flood hydrologystudiesleadstoinaccurateandextremelyoverestimatedestimatesofrainfallandflooddischarge.Analysis ofPrecipitationDataPrecipitationrecordsindicatethatlargerainstormsfrequentlyoccurfarbelowanelevationof about 7,500feet.Millerandothers(1984)listmanystormsinColo rado,includingthe1938SpringCanyonstorm nearFortCollins,the1938 MissouriCanyonstorm near Masonville,the1948FortCollinsstorm,the1948 Tucker Gulch stormatGolden,andthe1975BigThompsonRiverCanyonstorm,allresultingfromintensethunderstorms. However, documented floodsresultingfromintenserainfallarepracticallynonexistentabove about 7,500feet.StreamflowandprecipitationrecordsfortheBigThompsonRiver floodindicatethatprecipitationwassmall above 7,500feetexceptaroundisolatedmountain peaks. SeveralstudiesthathaveevaluatedhigherelevationprecipitationinColoradosupporttheconclusionthatsnowmelt floods predominate above 7,500feet.Henz(1974),inananalysisof Lamar, Colorado,radarimagery ofsummerthunder storms, foundthatathunderstorm'shotspotsoriginateatorbelow 7,500feetandgenerallymoveeasterlyintotheplains.Hansenandothers(1978),intheirstudyoftheclimatography oftheColorado Front Range,reportthatalllargefloodproducing rainstormseastoftheContinental Divide occurred below 7,500feet.Crow(1983)studiedtheclimatologyoftheColorado FrontRangebyanalyzingdatafromsixclimatologicalstations,each having a record of30yearsormore.Hefoundthattheavailablemoisture inthehigherelevationsisa smallfractionoftheavailablemoisturethatfeeds convective stormsatthelowerelevationsoftheplainsjusteastofthemountains. PaytonandBrendecke (1985) analyzedrecordsoftwoprecipitationstationsintheBoulder Creek watershed. Thesetwostationsaresouth

PAGE 220

Jarrett209ofEstes Parkatelevationsof 9,900feetand12,280feetwith recordlengthsof21and18years.Theseauthorsfoundrainfallintensitieslessatthehigherstationthanatthelowerstation,andintensitiesatthesesitesweremuchlessthan has been observedatlowerelevationstations.PaleofloodStudiesHistoricandprehistoricfloods infoothillstreamsinColoradoarerecorded asdistinctivedepositsandlandforms invalleysandchannels.Theinterpretationofthesedepositsand landforms can provide important supplemental information aboutthespatialoccurrence,magnitude,andfrequencyoflargefloods.Inpaleofloodinvestigations,discoveringalackof evidence oftheoccurrence ofextraordinaryfloodsisas important asdiscoveringtangibleonsiteevidence of suchfloods.Geomorphic evidenceofextraordinaryfloodsinsteepmountainbasins,such as intheupperBigThompsonRiver,isunequivocal, easytorecognize,andlong-lastingbecause ofthevolumeandsizeofsedimentsdeposited(JarrettandCosta, 1986). Extensivepaleofloodstudieshave been conducted intheFrontRangeof Colo rado,particularlyintheBigThompsonRiverbasin.Paleofloodinvestigationsindicatethatfrequentandlargefloods have occurred in basins below 7,500feet.Nounequivocal evidence oflargewater floodsmuchhigher than bankfulldischargewasfoundinanystreamvalleyabove about 7,500feetintheColorado FrontRange.Costa (1983) developed methodstoreconstructvelocity,depth, anddischargefromthemaximumsizeofbouldersinhistoricflood-boulderdeposits.Thefrequency ofextraordinaryfloods canbeestimatedin anumberofways(Costa,1978a, 1978b). Followingthecatastrophicflood of 1976 intheBigThompsonRiver downstreamfromEstes Park(McCainandothers,1979), radiocarbondatingoftruncatedanderoded landformsyieldedanestimateofrelativefrequencyofthe1976flood. Thisdatingindicatedthatthe1976floodwasthelargestsincetheoccurrenceofglacialmelting 8,000to10,000yearsago.

PAGE 221

210Regional Flood-FreguencyRelationsHYDROLOGICRESEARCHFloodcharacteristicsalsoareneededatungagedsites.Pastapplicationsofregionalflood-frequencytechniques havefailedtoadequatelydescribetheflood hydrologyoffoothillstreams;generallythesetechniquessignificantlyoverestimateflood magnitude(JarrettandCosta,1986).Investigatorshave assumedthatthetotalbasinareacontributesrunoffduringrainstorms.However,studiesbyMcCainandJarrett(1976);JarrettandCosta (1983);andJarrettandCosta (1986) havedemonstratedthatrainfallfloodsarelimitedtoareasbelow about 7,500feetinthefoothillregionofColorado.JarrettandCosta (1986) developedregionalrainfallflood-frequencyrelationsforthefoothillsareaoftheSouthPlatteRiverbasininColorado. Thisanalysisonly used drainageareasbelow 8,000feet,whichisconsideredaconservativeelevationselection.Theserelationsareunbiased and agree withdischarge-frequencyrelationsdevelopedfromstreamflow-gagingstationdata.Forbasinsabove 8,000feet,snowmelt-runoff-derived floodcharacteristicsareused accordingtomethods developedbyKircherandothers(1985). Conclusions Amultidisciplinarystudy has been undertakentoprovide abetterunderstandingofflood hydrology inthefoothillsandmountainsofColorado.Precipitation,streamflow,andpaleoflooddatafromthefoothillregionindicatethatsnowmelt floods predominate above 7,500feet(variesslightlywith majorriverbasin),andrainfallfloods predominate below 7,500feetintheColorado FrontRange.However,thetheoriespresentedinthisreportalsomaybeapplicabletomountainousareasinadjoiningStates,buttheapplicationsvary accordingtoelevation.Theu.S. National WeatherServicenowissuesflash-floodwatches intheFrontRangeofColo rado, recognizingthegreaterflash-floodpotentialbelow 7,500feet(DenverPost,July24, 1985). Estimatesoftherecurrenceintervalofthe1976BigThompsonRiver flood vary widelywhenusingdifferenttechniquestodevelop aflood-frequencyrelation.Also,recurrenceintervals,basedontheregionalrelationsandonpaleohydrology, range widelyfromlessthan a2-yearfloodatEstes Parktoapproximately a 10,OOO-year

PAGE 222

Jarrett211flood intheareasofmostintenseprecipitation.Computedrecurrenceintervalsalsoindicatea 300-year floodfortheBigThompsonRiveratthemouthofthecanyon and about a10-yearfloodattheriver'sconfluence withtheSouthPlatteRiver, because ofattenuationoftheflood peakfromoverbankstorageandstreamflowdiversions(Jarrettand Costa, 1986). Flash floodsareextremelyrareathighelevations(above about 7,500ft)but can occurfrequentlyatlowelevations.References Costa,J.E.1978a "HoloceneStratigraphyin Flood-FrequencyAnalysis."Water Resources Research14:626-632. Costa,J.E.1978b "Colorado BigThompsonFlood: Geologic Evidenceofa Rare Hydrologic Event." Geology6:617-620. Costa,J.E.1983"PaleohydraulicReconstructionofFlash-floodPeaksfromBoulder Deposits intheColorado Front Range." GeologicalSocietyof AmericaBulletin94:986-1004. Costa,J.E.,andJarrett,R.D.1981 "DebrisFlowsinSmall Mountain Stream ChannelsofColoradoandtheirHydrologicImplications."Associationof EngineeringGeologistsBulletin14: 309-322. Crippen,J.R.1978 CompositeLog-TypeIIIFreguency-Magnitude CurveofAnnualFloods.U.S.Geological Survey Open-File Report 78-352: 5.Crow,L.W.1983"ReviewofPertinentMeteorologicalFactorsRelatingtoPeak Streamflow FeedingComancheReservoir."Denver: UnpublishedreportonfileatMcCall-Ellingson&Morrill,Inc.,Engineers. 87.Elliott,J.G.,Jarrett,R.D.,andEbling,J.E.1982AnnualSnowmeltandRainfallPeak-Flow DataonSelectedFoothillsRegion Streams, SouthPlatteRiver, Arkansas River,andColorado River Basins, Colorado.U.S.Geological Survey Open-File Report 82-426: 86. Hansen,W.R., Chronic, John,andMatelock, John 1978 ClimatographyoftheFrontRangeUrbanCorridorandVicinity,Colorado. U.S. Geological SurveyProfessionalPaper 1019: 59.Henz,J.F.1974"Colorado highplainsthunderstorm systems, adescriptiveradar-synopticclimatology."FortCollins:ColoradoStateUniversity.Master'sthesis.66.

PAGE 223

212HYDROLOGICRESEARCHJarrett,R.D.,andCosta,J.E.1983"MultidisciplinaryApproachtotheFlood HydrologyofFoothillsStreamsinColorado." InA.I.JohnsonandR.A.Clark,Eds. Bethesda, Maryland.InternationalSymposiumonHydrometeorology, American Water ResourcesAssociation:565-569.Jarrett,R.D., and Costa,J.E.1985Hydrology, Geomorphology,andDam-BreakModelingoftheJuly15, 1982,LawnLakeDamandCascadeLakeDamFailures,Larimer County, Colorado.U.S.Geological SurveyProfessionalPaper 1369.[inpress].Jarrett,R.D., and Costa,J.E.1986"EvaluationoftheFlood Hydrology intheColorado FrontRangeUsing Streamflow RecordsandPaleoflood DatafortheBigThompsonRiverBasin."BatonRouge,Louisiana.InternationalSymposiumonFlood FreguencyandPeak Analyses,May14-17, 1986:[inpress].Kircher,J.E.,Choquette,A.F.,andRichter,B.D.1985EstimationofNatural StreamflowCharacteristicsinWestern Colorado.U.S.Geological Survey Water-ResourcesInvestigationsReport 85-4086: 28.McCain,J.F.,andJarrett,R.D.1976Manualforestimatingfloodcharacteristicsofnatural-flowstreams in Colorado. TechnicalManual1. Denver. Colorado Water Conservation Board: 68.McCain,J.F.,and Ebling,J.L.1979A PlanforStudyofFlood HydrologyofFoothillStreams in Colorado.U.S.Geological Survey Open-File Report 79-1276: 29.McCain,J.F.,Hoxit, L.R.,Maddox,R.A., Chappel,G.F.,andCaracena, Fernando1979StormandFlood ofJuly31-August1,1976,intheBigThompsonRiverandCacheLaPoudre River Basins, LarimerandWeldCounties,Colorado.U.S.Geological SurveyProfessionalPaper 1115: 152.Miller,J.F.,Hansen, E.M., Fenn, D.O.,Schreiner,L.C.,andJensen,D.T.1984 Probablemaximumprecipitationestimates--UnitedStatesbetweentheContinental Divideandthe103rd meridian.SilverSprings,Maryland:U.S.Department ofCommerceNational OceanicandAtmospheric Administration,Hydrometeorological Report 55: 245. Payton, E.A.,andBrendecke,C.M.1985"RainfallandSnowmelt FrequencyinanAlpine Watershed." Pages 25-36inProceedingsofthe53rdAnnualWesternSnowConference. Spokane, Washington: WesternSnowConference. U.S.InteragencyAdvisory CommitteeonWater Data 1981 GuidelinesforDetermining Flood-Flow Freguency. (2nded.,revised)[editorialcorrectionsmadeMarch1982]. Reston,Virginia.U.S.Geological SurveyOfficeofWater Data Coordination2:variablepaging.

PAGE 224

AGEOLOGISTSPERSPECTIVEOFTHE1982ESTESPARKFLOODWi11iamH.HoytDepartmentofEarth Sciences Universityoftlorthern Colorado Introduction Floodshaveinvokedterrorin themindsofhumansthroughoutallof our existenceonthisplanet.Virtuallyevery ancientculturehas recordedterrifyingaccounts ofcatastrophicfloods.ExamplesincludeMesopotamianfloddSfromtheTigrisandEuphrates River, Indian floodsfromtheGangesandBrahmaputra Rivers,andthe Noachian floodfromtheBible'sOldTestament.Today,wemayhaveevenmorereasontobewaryof floods than the ancients did.Amongthemanytypes of naturaldisasterswhichoccuronthe planet (earthquakes, volcanoes, vicious storms,El etc.),floods stand alone inoneimportantrespect:they occur withmorefrequencyandgreatermagnitUdetoday than they everhavein thepast.Why?Whatisitthatcausesmoresevereandmorefrequent floods inthismOdernage?Is theresomenatural explanation, orhaveweourselves broughtonthisdanger?Oneneednotlookfarto discoverthatmankinahasundertaken a "campaign ofperil"whichhasdramatically increased the likelihood of major floods inmanyrivervalleys.Themajorfactorsinclude:1)the construction ofdamsandreservoirs,2)the paving of vastriver-valleyareas,and3)thedeforestation/defoliationof large landareas.All of thesehavetheeffectof concentratingmuchlargerquantitiesof water inriversthanWOUldbethereotherwise. For example, thepeakdischarge during theLawnLakeflood(calculatedforthe Roaring River -FallRiver junctionshownonFigure1)wasapproximately12,UOOft3/sec.(JarrettandCosta, lY84). Consideringthatthe "bOO yearflOOd"here containspeakdischarges of only about400ft3/sec.,itbecomesobviousthattheLawnLakedamfailurecannotevenbeconsideredasa naturalflOOdfor the Roaring River drainage basin.Wehavecreated a "supernatural" floodbyimpounding

PAGE 225

214ESTESPARKFLOODlarge excessvolumesof water behindanartificialdam.Inaddition,wehavecontinuedtobuild our dwellings inperilousspots,despitesomestateandfederalregulationsdesignedtoprotectusfromsuchperil.Althoughdamsprovide themeanstostoreourmostvaluable planetary resource, they alsostorevastpotentialenergy in theformofliquidwater.Whenadamfails,gravityaccelerateswater downhillasanawesometorrentwhichcancausedestructionalmostbeyondcomprehension.10',')',I .JrPARk I '" o S, 30' -l----r--1 RI>!I rl_______. :c"'-.';3"'-0" "'l',r,,/---'22'30"IOS'41.1')"]0' -----12MILESII!2 KILOMETERSFigure 1.Mapof the study region west of Estes Park, Colorado.Thesecondfactor,paving ofrivervalleys,hastheeffectof preventing rainwaterandrunofffrompercolatingintothesoilandbeing storedthere.

PAGE 226

Hoyt215Withoutthisstorage in theaquifers,the water drainsintotheriver and overtopsitsbanks.(Incidentally,the loss of recharge to the aquiferisanother serious environmental consequence). Sincemostmajorindustrialcentersandcitiesoftheworld areonmajorrivers,wehaveano-winsituationwherepaving of thecitydamagesthecapabilityof theriversystem to handle flood watersandtheriversystemthereforedamagesthecitymoreseverly.NewOrleansisa majorexampleofthiscarriedtoextremes.Thethirdanafinalfactoristheoeforestationanddefoliationof land areas. This alsohasthe tendencytoreduce theamountof waterusedbyplantsaswellasreduce theamountof water stored in thesoilandinaquifers.Asin the case of paving,thisaction increases runoffintoriversandthereby increases the frequencyandmagnitude of floods. This denudation of the landscape alsoacceleratessoilerosionandproduces a badlydamagedlandscape.Thebadnewsinthissituationisthatwecontinuetoplace ourselvesinmoreseriousperilbyincreasing thesedeleteriouseffects.Unfortunately,othernaturaldisasterssuchasearthquakes, volcanoes,andstorm' triggerfloodsandthen magnifydamages.Thegoodnewsisthatnoweducation,earlywarning systems,andemergencypreparedness oftenwarnpeoplptoescape the path of the deadly flood waters,atleastincountrieswherecommunications are very swiftandeffective.Anexampleofhowthese speedy communicationscanradicallyreduce the deathtollfroma floodhasbeenaffordedbythe recentfloOdSontheFallRiverandBigThompsonriversystem in Colorado.Eventhough theywereboth in thesamegeneral area, the1976BigThompsonCanyonfloOdkilled140people but the 1982 Estes Park floodkilledonlythree.Awareness, education, communication, abitof luck,andthe lessons of1976madethedifference.Anexcellentexampleofcatastrophicsedimentemplacementduring a flood hasbeenprovidedbythe"alluvialfan"floOddepositwhichresulteofromtheLawnLakeflood. Detailed sedimentary analyses ofthisflood deposithavebeenmadeinanefforttousethismodernflood deposit to understandandidentifyancient flood deposits.TheSettingofTheFloodOnthatpeaceful July morning, the authorwasgoing overanexamination with twenty geology studentsatthe University of Northern Colorado'sOldManMountainLodge,amere300metersfromthe Fall RiveraboveEstes Park, Colorado.Itwasa typicalRockyMountaindawnin Estes Park--clean,crisp,andquiet.Quietuntil

PAGE 227

216ESTESPARKFLOODabout 8:30 a.m.,thatis.Inthe duration of aboutfiveminutes,helicoptersswarmeaoverhead,sirensblared out, thepowerwentout, thephonewentdead,anathe water stopped flowingfromthetaps.Afeelingdevelopedthatsomething bigwashappeningandthatour plannea geology excursiondowntheBigThompsonCanyonwasinsomejeopardy.Uponinvestigationof thesituation,wediscoveredthatthe Fall Riverhadturnedintoaterrifyingtorrentofmudanaboulders.Theriverwasupout ofitsbanks, over the roadsandbridges,andsome14timesmorewaterwascomingdowntheriverthanjustafewminutesearlier.Thehouseonthe cornerwasgone,movingdownstreamlikesomegiantbatteringram.Theentirecentralsectionof Estes Parkbecameariverbeaandthe buildings in themainaxis of flowweresometimes dismantledanddestroyed.Theexact sequence of events hasbeenthoroughly discussedbyMiller, CostaandJarrett, 1983; Hoyt, anaJarrettanaCosta,1984.ThebeorockterrainthroughwhichthefloOdhaapassedwaslargelygranitewithlesseramountsof gneiss,schist,anda smallamountof volcanic rock(Richmond,1974;Chronic, JustaboveHorseshoeFalls,the flooa watershadcutdownabout20meters through aglaciallateralmorainewhichhadbeendepositea during thelastmajorglaciationin the area (Figure 2).Thetwomineral specieswhichdominated the assemblage ofmaterialserodedbythe floodwerequartzanofeldspar.Onemainfocus of geological researchonthe floodhasbeenthespectacularfan-shapedpileof boulders, cobbles, sand,silt,andclaydepositedjustdownfromHorseshoeFalls(Figure3).Oneof thefirstquestions tobeanswereawashowmuchsedimentwasdeposited in the fan.BasedonnewtopographicmapsassembledbyHoyt(1983)andhis co-workersaswellasmeasurementsmaaebyCoataandJarrett (1983) andCrewsandothers (1985) the fan depositwasfound tobeupto20meters thickatitsthickestpointandcontainsonthe order of106 metric tons of rock. Thatisenoughtofilla largefootballstadiumuptothe top.Aroundthe peripheral areas of the fan,aninexpensive but accuratemethodof thickness measurementwasused.VirtuallyeveryAspentree(Populus tremuloidesMichaux)inthisareahasbeenscarredbyElk"bJrking". This leaves adatumplaneonthetrees203cm off the ground (basedon100Aspentreesmeasurea in thearea).Thethickness of the depositcanbecalculatedfrompartlyburiedtrees.Issuesforthe Future Every time a flood occurs,welearnmoreabout the processesandproauctsof

PAGE 228

217thesecatastrophicevents.JarrettandCosta (1983)haveproduced a thoroughsynthesisofnewinformation about theLawnLakefloOdanatneyhaveconcludedthatthevolumeof waterwhichcamedownthe Roaring River during theLawnLakefloOdhadnotbeenequalled in thepast 10,000 years or longer. Figure 2.Viewofglacialmoraine atopgraniticbedrockatHorseshoeFalls.Theflood waters cutsome 20 metersdownthrough the boulders, sand,andsiltof thelateralmoraine (note personforscaleatthe middle of the photo). Figure 3. Photograph lookingaownthe boulaer fandeposittothesoutheast.Horse shoeFallsisdirectlybehinothephotographer.Itiscertainlyclearthatnowwearedirectlycreatingcertainconditionswhichincreasethelikelihoodof dangerousandcostlyfloods.TheLawnLakeDambreakandsubsequent Fall River floodraisedagaintheissueofculpability:whoisresponsibleforpayingfor $31 millionindamages?LawnLakeitselfisonNational Park Service land, but the dam wasinspecteobystatepersonnelandthe water inthelakewasownedbya farmers co-op innortheasternColoraoo.Theissues aresolegallycomplexandclouded because thedamwasconstructeoabout the turn ofthecenturyandhasclearlyoutliveditsexpected engineeringlife.Governmentsandcitizensseemtoaccept the precarious balancemanyof ourdamsexistin.Wealsoseemtotakeforgrantedthattherearenoworkablesolutions.Let'schangethis.There are several policy changeswhichwouldgreatlyreducethedanger of major flooddisastersin the UnitedStates.These canbeoividedintotwotypes:1)policieswhichwouldreduce thelikelihoodof a flood

PAGE 229

218ESTESPARKFLOODeverstarting,and2)proceduresandtechnology toconstantlymonitor thestructuralintegrityofdams.Theobjectivesof thefirsttypewouldbeto reduce theamountof paving,deforestation,defoliation,andconstruction ofdamsinrivervalley areas (floodplains)assacredgrounonot tobe"developed."Theriverneedsthatlandtohelp controlitself.Furthermore, the placement ofdamsin high mountain valleysabovepopulationcentersseemsunnecessary; indeed the only argument in favor of trapping waterinareas of steepand"hydraulicallydangerous"terrainisthatwefeel compelled to hold ontoanarchaicandlegallycomplexwater policy.Itmakesmuchmoresense toletthe water flow downhillfromthe mountains to theplainswherethe waterisneedeaanyway.Ifadamfailsanthe gentlegradientsof theplains,thethreattolifeandproperty willgenerallybemuchless.Thesecond imperativewhichseemsobviousistoimproveourabilitytoconstantlymonitor thestructuralintegrityofdams.Whydowefeel compelled to waituntilthe wallofwaterisbearingdownonusbeforewearewillingtodoanything about prevention? Variousindustries rely onadvanced deformation meterscalledstraingauges to monitormovementofearthmaterials(inmineshafts,forexample);atthe veryleast,warning devices couldbecheaplyinstalleddownstreamfromdams.Thenwewillknowtheinstantadamfailsandimperilslifeandproperty. Iamquiteconvincedthatsuch a warning system couldhavebeeninstalledatLawnLakeforconsiaerablylessthan$31millionanathreehumanlives.Ofcoursethatisanoverstatement, butevenifweaddallthesitesofpotentiallydangerousdamsinthewholestateof Colorado, thecostwouldstillprobablybebelow $31 million.Themonetaryandhumanlosses coulahavebeenmuchworse--Estes Parkwasrelativelyluckythistime. Therehasbeensignificantprogressonthesefrontsin recentyears,but the progressseemspainfullyslow.Thethreatsof flooasseemasdiretadayastheywerelastyear, butwealwaysseemtobesurprisedbythesecatastrophies.I believe the timeisoverauetoreassessour waterpoliciesinmanagingrivervalleys. We havetechnologywhichcould help us, butweare not usingittoourfulladvantage. hopeisthatcommonsense willsoonovercomethe bureaucratic processsothatmanagementof high mountainrivervalleys willbetterassure thesafetyof mankind.

PAGE 230

HoytReferences Chronic, Halka1980Roadside Geology of Colorado. Missoula, Montana: Mountain Press PublishingCo.219Costa,John 1983 E.andRobertD.Jarrett"Geomorphicandseoimentologicfeaturesof theLawnLakeDamfailure."GeologicalSocietyof America,Abstractswith Prograllis, Vol. RockyMountain National Park, Colorado:356-388. Crews,S.,Harvey, 8lair,1.,andPitlick,J.,1985"Holocene Braided Rivers of Eastern ColoradoandtheSedimentol09icEffectsof theLawnLake Dam FailureinRockyMountain National Park."InSociety ofEconomicPaleontologistsanaMineralogistsMioyear Meeting FielaGuioes Hoyt,Wi11 iam H.1983"Sedimentaryanohydrauliccharacterofanalluvialfan flooodeposit."Pages 356-388inGeologicalSocietyof America,Abstracts \,ith Programs,Vol.15,No.5.Jarrett,R.1984D.,andCosta,J.E."Hydrology, geomorphology,anddam-break modelingoftheJuly lS, 1982,LawnLakeanaCascadeLakedamfailure,Larimer County, Coloraoo": U.S. Geol. SurveyProfessionalPaper 1369. /'li 11er,Gardner1982 LawnLakeDamBreakandFallRiver Flooo. Estes Park, Colorado,VIPPrintingCo.Richmond,GeraldM.1974Raising theRoofof the Rockies.Bozeman,Montana.RockyMountain NatureAssociation.

PAGE 231

ThispageISblank

PAGE 232

PARTSIXWHEREDOWEGOFROMHERE?

PAGE 233

ThispageISblank

PAGE 234

POLICYANDRESEARCHRECOMMENDATIONSEveC.GruntfestDepartment of GeographyandEnvironmentalStudiesUniversityofColorado, Colorado SpringsAfterThursdayandFriday'splenaryandpapersessions,working groups were convenedtoestablishpolicyandresearchagenda inthreecategories:mitigationandrecovery,hydrologyandgeomorphology,andforecastingandwarning.Thegroupsmetanddevelopedflashfloodguidelinesandrecommendationsfortherestofthecentury.Attheclosingsession,reportersfromtheworking groupsreportedtheresultsofthesessions;thesearelistedattheendofthisdiscussion.Fivemainpointsemergedfromtheworking group recommendations.1.Thereisagreaterneedfortransferofavailableflashflood hazardmitigationinformationtoa broader range ofconstituenciesthanthereisforacquisitionofnewdata.Translatingresearchresultsforuseatthelocalandstatelevelshasbecomeahigherpriorityformanyphysicalandsocialscientists.Accountabilityforworkinnaturalhazardsmitigationgenerallygoes beyondthecasestudy orlaboratorysettingtoatleastrecommendationsforapplicationbylocalofficials.Therelationshipbetweentheresearchandpolicycommunitiesisbetterestablishedandfocusesmorefrequentlyonproblem-solving.Thecontributionsofresearchersandpolicymakers,particularlyintheworking groupsessions,atthisSymposiumareevidenceofthisconstructivetrend.2.Thecallforheightenedpublicawarenesscontinuesbut with amorevarieddefinitionof"publics".Whiletheinterestinraisingpublicawareness has been aconstantfeatureofnaturalhazardsresearchsincetheearly1970's,thenatureoftheeffortshasbecomemoresubtleandsophisticated.For example, localflashfloodpubliceducationeffortsnownot onlydescribethehazard dynamics, butalsopointout

PAGE 235

224RECOMMENDATIONStheadvantagesandconstraintsof alocalwdrning system. Public awareness programsanticipatetheinformationneeds oftheelderly,children,industries,andpublicofficialsintheevent of aflashflood.3.Betterestimatesof floodlosses,benefitsandcostsofmitigationstrategies,andimpacts offutureandpresentconditionsareessentialforimproveddecisionmaking. This recommendationwasmadeinseveralworking groups.TheNational Flood Insurance Program, Federal EmergencyManagementAgency,stateemergencyservicesagencies,andevenprivateinsurancecompanies needbetterdataontheexpectedcostsandbenefitsof aselectedmitigationstrategy.Moreprecisecalculationofintangiblecostsof floods mightsignificantlyimprovethelikelihoodthatlong-termstrategiesforfloodlossmitigation,such asacquisitionandrelocation,wouldbemoreattractivetolocalcommunities. Thereisacontinuingneedforbetterquantificationoftheimpacts ofpotentialurban developmentondownstream flood hazardssothattherisksaresimply notshiftedtopre-existingdownstreamstructures.4.Differentlevelsof governmentandprivateconsultantsneedtoclarifytheextentoftheirlegalandethicalresponsibilitywith regardtopublicprotectionfromflooding.Thereareseriousquestionsaboutthedistinctopportunitiesandbestallocationofresourcesbetweenthepublicandprivatesector,particularlyinterms ofprovisionof weatherforecastingandfloodinsurance.Communities canbenefitfromthecoordinatedeffortsoftheNational WeatherServiceandprivateforecastingfirms.Flash floods haveshortleadtimes,but communitiesatriskcanutilizeaprivatefirmtoprovidethemaximumamountof timeandthemostprecisioninforecasts.However,thegoals should notbecompeting; they shouldbeintegratedinordertoprovidethemostlocalandtimelyinformationpossibletothecommunityatrisk.Extensive focused debateisnecessarytoclarifynot onlyhowbesttocoordinatetheefforts,butalsotoidentifythelegallimitof whatthepubliccan expect with regardtodamsafetyorwarningreliability.Theperennialquestion,"Howsafeissafeenough?" shouldbebetterresolved.

PAGE 236

Gruntfest5.Thedistinctionsbetweenflashfloodsandslow-risefloods shouldbeclarified.225Traditionally,flood hazard mapping hasidentifiedfloodplainswithout regardtodebristhereinwhichwillcompoundtheeffectsofflooding.FortheBigThompsonflood,seriousdisagreementexistsamongthehydrologistsconcerningtheflood'sreturnintervalandthealtitudeatwhichwecan expectseriousmountainprecipitationcausingflashfloodstooccur.Betterunderstandingoftheuniquecharacteristicsofflashfloodsmayhelpresolvethedisagreement, oratleastclarifythepointsonwhichhydrologistsagree.TheSymposiummarksanimportantmilestonewith regardtoflood hazardmitigation.Thirtyfederalrepresentatives,12stateofficials,20localofficials,29universityrepresentatives,fourmembersof ofthepress,17privateconsultants,andfourprivatenon-profitorganizationrepresentativestookpartintheSymposium.Thisdistinguishedandvariedgroup gatheredtoassessflashfloodvulnerabilityandmitigationalternatives.Thestageisnowsetforfurtherpost-audits.InJune,1987,a lS-year anniversarysymposiumwillbeheld in Rapid Citytoreview achievementsandchallengessincethat1972catastrophe.Newcommunication channelsestablishedamongvariouslevelsof government,andamongstates,researchersandpolicymakerswillensurethatflashfloodlossreductionhas a higherpriority.While notalltheSymposiumdiscussionsfocusedonaccomplishments,difficultchallengeswereidentifiedandacoordinatedapproachformeetingtheminthefuturewasproposedbyparticipants.Enumerated belowarekernalsthatshouldgrowintofurtherinvestigationsanda broader exchangeofideas inflashflood hazardmitigation.Recommendationsaredividedintofourcategories:mitigation,recovery, hydrologyandgeomorphology,andforecastingandwarning.

PAGE 237

226RECOMMENDATIONS Po1isx. Themitigationpolicyrecommendations emphasizetheneedforeducation,knowledgetransfer,andcoordinationamongagenciesandindustries.1)Promote education ofchildren,professionals,publicofficials,andthegeneralpub1ic.2)Encouragegreaterparticipationof realestateandinsuranceindustries.3)Mandatefederalinteragencycoordination.4) Promote local hazard awareness. 5)Fosterknowledgetransfer.6) Emphasizemultiplebenefitsofmitigationstrategies.7)Encouragetheadoptionofmandatorymitigationactions.ResearchThemitigationresearch recommendations emphasizetheneedforresearch inmitigationmethods--existingandfuture--andrelatedeconomic concerns.1)Validationofexistingphysical-economic-sociologicalmodels.2)Comparative values ofmitigationtechniquesandtheiradequacy,e.g.,the1985evaluationofTVAprograms. 3) Analysis ofexistingmethodsanddevelopmentofimproved methodsforevaluatingdisasters.4)Inclusionof time elementinthesemethods.5)Assessment of impactofmitigationfortotalvs.partialdestruction.6)Economicincentives/costsinmitigation.7)Economicimpacts ofdisclosure.

PAGE 238

Gruntfest2278)Multiobjectiveeconomic concernsindevelopmentandrehabilitation.9)Legalandpolicyimplicationsofmitigationandrecovery measures,presentandfuture.10)Riskidentification,assessment, management,andcommunication.11)Continuedandupgraded mappingeffortsatalllevels.Po 1.-i.-c..l Therecoverypolicyrecommendationsstresseconomic concernsandtheneedforstreamliningtherecoveryprocess.1) Determinewhopaysforwhat.2)Analyzewhobenefits.3)Promotemultiplebenefitsof recoveryefforts.4) Encouragecreativefinancing,ie.,pre-eventmechanismsandconditionalaid.5)Streamlinetherecoveryprocess.6) Evaluaterebuildversusrelocate.ResearchTherecoveryresearchrecommendations emphasizetheneedforincreasedcommunicationandknowledgetransfer,andanassessment oftheroleofinsurance.1)Transferof knowledgeforspecificuses/users.2)Communication enhancementamongscientificandresearchcommunities(researchandoperations).3)Local/victimsinputinresearch.4) Developmentofcriteriafornormalized, generalandspecificdata/information.

PAGE 239

228RECOMMENDATIONS5)Economicconsiderations/parametersinresearch.6) Innovativefinancialmechanismsforresearch.7)Assessment ofrelationbetweenriskandinsuranceratesin recoveryandmitigation.8)Effectivenessofinsuranceas mechanism in recoveryandmitigation.9) Impacts ofactualandfutureinsuranceschemes. 10)Liabilityasfactorinresearch.PolicyThehydrologyandgeomorphologypolicyrecommendations emphasizetheneedforincreasedspecificknowledgeonwhichtobasepolicydecisionsandassessments oftheimpacts of developmentonfutureflooding.1) All governments shouldtakeintoconsiderationtheriskoflifethreateningfloodsrelatedtodamsafetyandfloodplainmanagement.2)Floodplainanalysisshouldbebasedongeomorphologicconsiderations(erosionpotential,debrisflow) as well asonhydrologicconsiderations.3)Determineiffuture(fullyurbanized) hydrology orexistingconditionhydrology shouldbeusedtoidentifytheregulatedfloodplain.4) Government shouldinsurethatadequateinformationisavailablebeforedecisionsaremade.5)Policy shouldbebasedonthebestavailablehydrologic,geomorphologic,meteorologic,andenvironmentalinformation.6)Development shouldpayfortheincreasedrunoffitcauses.7)Hydrologicpolicyassociatedwithdamsafetyshouldtakeintoaccountspillwaydesign flood frequency,PMFversusanotherfrequency,andriskanalysis;itshould promote hydrologytrainingofdamowners;anditshould determineresponsibilityandwhoshould pay.

PAGE 240

GruntfestResearch229Thehydrologyandgeomorphologyresearchrecommendations emphasizetheneedforanexamination ofthedistinctionsbetweenflashfloodsandslow-risefloods,ofthereturntime ofevents,andofdebrisbulking.1)Differencesbetweenriverinefloodingprocessesandpredictionsandflashfloodprocessesandpredictions.2)Determinationofdatesandreturnperiodsofhistoricandprehistoricmajorflashfloodevents.3)Relationshipofreturnperiodsforspecificsitestoriskata regionallevel.4) Comparisonofexceptionalrainevent above Drake withpossiblesimilareventselsewhere intheBigThompsonbasin. 5) Study ofgeologicprocessestriyyeredbyintenseprecipitation.6) Thresholdsfordebrisflows(bulking)initiation.7)Mappingtodeterminearealandaltitudinalextentofflashfloodinginmountainregions.8) Impact of overbankfillonpeakflooddischarges(i.e.,floodwayfringein floodinsurancestudies).9)Erosional,transport,anddepositionalprocessesduring peak flows. 10)Selectionof channelcross-sectionforwatersurfaceprofilecomputationandthalwegdetermination(toavoiderrorsincrosssectionalareasandunderstanding flood magnitudeCQ).11) Changes in channel(i.e.,predictedfloodplainelevations)becauseofdepositionanderosion.ForecastingandWarning Policy Threemainterms weredefined:Forecasting:hydrologic-meteorological,datacollection(hardwareincludesnewprecipitationgauges whichoffermorecoverageatlowcostbutarelessaccurate),andmodelingandprediction(forecastmodelingincludesGOESNEX.NEXRAD.VERTICALPROFILING.andNEXRADAlgorithms);

PAGE 241

230RECOMMENDATIONSWarning: messagepreparationanddissemination;andResponse: damage-reducingandlife-savingactionbycommunitiesandindividuals(includespreparedness).1) Policy shouldtakereliabilityoffloodpredictionsintoaccount.2)Promote technologytransfer.3)Fostermaximizingappropriateresponses.4)Increasemapping(applicationofexistingknowledge).5)Promote awarenessof"public"andlocalofficials,especiallydifficultin absence ofrecentfloodexperience.6)Emphasize value ofadditionaltimeandreliability(criteria).7)Encourage systeminstallation.8)Coordinatefederalactivitiesinforecasting,warningandresponse.9)Defineroleofdifferentlevelsof governmentandprivateaction.10) Determinewhatlandofficialsshouldbetaught.Research Therewasconsensusthatforecastingistheprimaryareain whichresearchisneeded. Responseratedasthesecond-mostcriticalareaforfutureresearch.Thepercentages,basedontheparticipantsattendingthisworking group,areshownbelow.ForecastingandWarning ResearchKeyIssues(N=ll)ForecastingWarning ResponseAgencyCoordinationIdentifyHighRiskSites1st54% 9% 36%2nd(W=10)30%20%30%10% 10%

PAGE 242

APPENDICES

PAGE 243

ThispageISblank

PAGE 244

233APPENDIXIPARTICIPANTLISTADAMS,ChristopherR.DenverOffice ofEmergencyPreparedness CityandCounty Building,Room3 Denver,CO80202(303) 575-2616ADAMS,Gerald U.S.ArmyCorpsof Engineers700Federa1Building601East 12th StreetKansasCity,MO64106(816) 374-5275BAILEY,AnnGrandForks Herald 12ONorth FourthStreetGrandForks,ND58206(701) 780-1117BARRETT,CurtisB.NOAA/NationalWeather Service806013thStreetSilverSpring,MD20910(301) 427-7624BASSETT,DianaColoradoWaterUsers RiskManagementAssociation4322Highway66Longmont,CO80501(303) 535-4267 (303) 535-4474BELVILLE,JamesD.National Weather Service806013thStreet,Room1326SilverSpring,MD20910(301) 427-8090BERNSTEIN,AbramB.NationalAcademyof Sciences2101ConstitutionAvenueWashington,DC20418(202) 334-3377BIRCH,DanCityofBoulder1739BroadwayPost OfficeBox791Boulder,CO80306(303) 441-3240BOLTON,PatriciaBattelleHumanAffairsResearch Centers4000NE41stStreetSeattle, WA 98105(206) 525-3130BRADLEY,WilliamC.Department of Geological SciencesCampusBox250University of Colorado Boulder, Colorado80309(303) 492-6188BROWN,RodgerA.National Severe Storms Laboratory1313HalleyCircleNorman,OK73069(405) 360-3620BUNT!NG,DanRegional Building Department101WestCostillaColorado Springs,CO80903(303) 578-6230 or 578-6802BYRNE,JohnP.(Pat) Colorado Division ofDisasterEmergencyServicesEOC,CampGeorgeWestGolden,CO80401(303) 273-1624CARTER,T.MichaelNOAA/NationalWeather Service806013thStreetSilverSpring,MD20910(301) 427-7970

PAGE 245

CHAPPELL,Charles F. Weather ResearchProgramNOAA/ERL/R/E22325BroadwayBoulder,CO80303(303) 497-6186CHARNEY,Michael Forensic Science Laboratory ColoradoStateUniversity FortCollins,CO80523(303) 491-1486CLARK,RobertO.Department of Geography University of SouthFlorida4202FowlerAvenueTampa,FL33620(813) 974-2386or2389COOK,RichardA.JeffersonCountyEmergencyPreparedness1701ArapahoeStreetGolden,CO80419(303) 277-8215DALLMAN,John Department of Civil Engineering University of ColoradoatDenver1100FourteenthStreetDenver,CO80202(303) 556-2739or494-4173DEBROT,MarjorieL.U.S.ArmyCorps of Engineers700Federal BuildingKansasCity,MO64106(816) 374-5275DeGROOT,WilliamUrbanDrainageandFlood ControlDistrict2480West26th Avenue,#156-BDenver,CO80211(303) 455-6277DYE,Wi11iamM.Consultant Post OfficeBox3224Estes Park,CO80517(303) 586-6154EVANS,BarbUtilitiesDevelopment Services City of Boulder1739BroadwayPost OfficeBox791Boulder,CO80306(303) 441-3240FLACK,J.Ernest Department of Engineering UniversityofColoradoCampusBox428Boulder,CO80309(303) 492-7111 orGARNER,JoeRockyMountainNews 400WertCol fax -Avenue Denver,CO80204(303) 892-5421GASKILL,HowardNewHampshire Civil Defense107PleasantStreetConcord,NH03301(603) 271-2231 (800)852-3792GERLACH,RodLoveland Daily Reporter-Herald450C1 evelcind-Avenue----Loveland,CO80537(303) 669-5050GORDON, Wi 11iamI.Larimer County Office ofEmergencyManagementPost OfficeBox1190FortCollins,CO80522-1190 (303) 221-7961GORE,DouglasFEMA/RegionVIII Building 710,Box25267Denver Federal Center Denver,CO80225-0267 (303) 235-4830GRAHAM,WayneU.S. Bureau of ReclamationMailCode753Post OfficeBox25007Denver,CO80225(303) 236-3785

PAGE 246

GRUNTFEST,EveC.Department of GeographyandEnvironmental StudiesUniversityofColorado Colorado Springs,CO80933(303) 593-3513HAGAN,PatriciaColorado Division ofDisasterEmergencyServicesCampGeorgeWestGolden,CO80227(303) 273-1773HOLDEN,BobAmericanRedCross MileHi9hChapter170SteelStreetDenver,CO80206(303) 399-0550,#79HOLDEN,LouAmericanRedCross MileHighChapter170SteelStreetDenver,CO80206(303) 399-0550,#79235HANDMER,JohnW.CentreforResourceandEnvironmenta 1 Studi esAustralianNational University Canberra,ACT2601Australia(062)494729HARRIS,KenU.S.ArmyCorps of Engineers Missouri River Division12565WestCenterRoadOmaha,NE68144-3869 (402) 221-7220HAVLICK,SpenserW.Department of Environmental DesignCampusBox314Universityof Colorado Boulder,CO80309(303) 492-6936HEIDEMAN,KenNOAA/ERL/PROFS/E23325BroadwayBoulder,CO80303(303) 497-6618HELBURN,Nicholas DepartmentofGeographyCampusBox260Universityof Colorado Boulder,CO80309(303) 492-6975HENZ,John F. Henz, Kelly&Associates1776South Jackson,#912Denver,CO80210(303) 759-1947HOOVER,Jerry,Lt.BoulderPoliceDepartment17776thStreetBoulder,CO80301(303) 441-3315HOSTETTER,C.Nelson MennoniteDisasterService21South 12thStreetAkron,PA17501(717) 859-1151HOWARD,KenNOAA/ERL/WeatherResearch prog ram/R/E22325BroadwayBoulder,CO80303(303) 497-6635HOYT,WilliamH.Department of Earth Sciences UniversityofNorthern Colorado Greeley,CO80639(303) 351-2487HUBER,CaroleJ.DepartmentofGeographyandEnvironmental Studies UniversityofColorado Colorado Springs,CO80933(303) 593-3513HUBER,JosephC.Minnesota Psychological Association AmericanRedCrossSt.PaulandMinneapolis Chapters1458GoodrichSt.Paul,MN55105(612) 774-2237or690-1973

PAGE 247

HUBER,ThomasP.Department of GeographyandEnvironmental StudiesUniversityofColorado ColoradoSprings,CO80933(303) 593-3166JARRETT,RobertJ.U.S. Geological SurveyBox25046,M.S.415Denver Federal Center Denver,CO80225(303) 236-4886JOHNSON,LynnE.Department of Civil Engineering University of ColoradoatDenver1100FourteenthStreetDenver,CO80202(303) 556-2739or494-4173JONES,Robert F. Department of GeographyandEnvironmental StudiesUniversityof Colorado ColoradoSprings,CO80933(303) 593-3513KELSH,MatthewTS Infosystems, Inc.c/oNOAA/ERL/PROFS/R/E23325BroadwayBoulder,CO80303(303) 497-6461or939-9615KIMBALL,FloydE.,Jr.FloodPlainManagementFieldOperations2617WestAndrewJohnsonHighwayMorristown,TN37814(615) 587-5600KIMZEY,Jan City of FortCollinsPostBox580FortCollins,CO80522(303) 221-6605KISTNER,RobertL.Colorado Division ofDisasterEmergencyServicesCampGeorgeWestGolden,CO80401(303) 273-1787KLASSEN,Daryle W. Larimer County Commissioner Post OfficeBox1190FortCollins,CO80522-1190 (303) 221-7003KNAPP,DavidCity of Boulder Post OfficeBox791Boulder,CO80306(303) 441-3004KNIGHT,A1RockyMountainNews400 WestCOlTaxAVenue Oenver,CO80204(303) 892-5452KOLENBRANDER,LawrenceG.Natural ResourcesManagementWestern Carolina University223StillwellCullowhee,NC28723(704) 227-7367KUSLER,Jon Attorney Post OfficeBox528Chester,VT05143(802) 875-3897LAMBERT,RonaldL.Greenhorne&O'Mara,Inc.3131SouthVaughn Way #228Aurora,CO80014(303) 755-9000LAMON,Rickie "Pete" CityofGatlinburg Post OfficeBox5Gatlinburg,TN37738(615) 436-7792LANG,LarryStateof Colorado Water ConservationBoard721Centennial Building1313ShermanStreetDenver,COB0005(303) 866-3441LEON,BillCenterforCommunityDevelopmentandDesign UniversityofColorado Colorado Springs,CO80933-7150 (303) 593-3441

PAGE 248

LIOU,JohnFEMA/RegionVIII Denver Federal Center Building710,Box25267Denver,CO80225-0267(303)235-4836McCUTCHEN,MaryB.Department of GeographyandEnvironmental StudiesUniversityofColorado ColoradoSprings,CO80933(303) 593-3513237LOMELI,BenArizona Department ofWaterResources99EastVirginiaPhoenix,AZ85004(602) 255-1566LOVE,DavidJ.DavidJ.Love&Associates,Inc.2995Centergreen Court SouthSuiteC Boulder,CO80301-5421 (303) 440-3439LOVE,NancyB.DavidJ.Love&Associates,Inc.2995Centergreen Court SouthSuiteC Boulder,CO80301-5421(303) 440-3439LOVELL,TroyLynnAlbertH.HalffAssociates,Inc.3914Sandshell Drive Fort Worth,TX76137(817) 847-1422LYONS,JamesGraduate School of Geography ClarkUniversityWorcester,MA01610(303) 752-1425MARCUS,AndrewDepartmentofGeographyUniversityof Colorado Boulder,CO80309(303)492-8311McADIE,Colin TS Infosystems,Inc.c/oNOAA/ERL/PROFS/R/E23325BroadwayBoulder,CO80303(303) 497-6719McCULLOH,JanFEMA/RegionVIII Denver Federal Center Building 710,Box25267Denver,CO80225-0267 (303) 235-4845McKEE,ThomasB.DepartmentofAtmospheric Science ColoradoStateUniversityFortCollins,CO80523(303) 491-8545MILETI,Dennis Hazards Assessment Laboratory ColoradoStateUniversityFortCollins,CO80523 (303) 491-6045 or5915MULLER,LarryA.Muller EngineeringCompany,Inc.7000West14thAvenueLakewood,CO80215(303) 232-9340 r1USGRAVE, Curt U.S.ArmyCorps of Engineers Missouri River Division PostOfficeBox103DTSOmaha,NE68101(402) 221-7218NAZARENUS,DottieCity of Fort Coll insPostOfficeBox580FortCollins,CO80522(303) 221-6605OLSON,JeromeFEMA/RegionVIII Building 710,Box25267Denver Federal Center Denver,CO80225(303) 235-4830OWEN,H.James FloodLossReductionAssociates4145MaybellWayPaloAlto,CA94306(415) 493-7198PAUTZ,MauriceE.Weather Service ForecastOfficeNOAA-NationalWeather Service10230SmithRoadDenver,CO80239(303) 361-0661

PAGE 249

PETERSON,JeromeQ.U.S.ArmyCorps of Engineers20Massachusetts Avenue,N.W.Washington,DC20314(202)272-0169PLATT,RutherfordLandandWaterPolicy Center Department ofGeologyandGeographyUniversityof Massachusetts Amherst,MA01003(413) 545-2499or2296RAINEY,Eri cM.Department of Earth Sciences University of Northern Colorado Greeley,CO80639(303) 351-2647RHODES,DavidDepartmentofPublicWorksP.O.Box791Boulder,CO80306(303) 441-3200RIDLEY,SkyeDepartment of GeographyandEnvironmental Studies University of Colorado Colorado Springs,CO80933(303) 593-3513RIEBSAME,WilliamE.Natural Hazards Information CenterCampusBox482University of Colorado Boulder,CO80309(303) 492-6312ROLD,John W. Colorado Geological SurveyRoom715,1313ShermanStreetDenver,CO80203(303) 866-2611SABADELL,J.Eleanora National Science Foundation1800GSt.N.W.Washington,DC20550(202) 357-9780SABOL,GeorgeV.1351East 141stAvenueBrighton,CO80601(303) 457-0989SCOFIELD,RoderickA.NOAA/NESDIS/Satellite Applications LaboratoryF/RA21,Room601, WWB Washington,DC20233(301) 763-8251SHORE,JamesH.,M.D.Department of Psychiatry Health Sciences CenterUniversityof ColoradoBoxC-2494200East 9thAvenueDenver,CO80262(303) 394-5248SMITH,Robert W. City of FortCollinsPost OfficeBox580FortCollins,CO80522(303) 221-6605SORENSEN,GrantR.WyomingDisasterandCivil Defense Post OfficeBox1709Cheyenne, WY 82003(307) 777-7566SORENSEN,JohnH.OakRidge National Laboratory Post OfficeBoxXOakRidge,TN37831(615) 576-2716SOULE,JamesColorado Geological SurveyRoom715,1313ShermanStreetDenver,CO80222(303) 756-5641STANTON, Uilliam P.Flood ControlandFloodPlainManagementSection Colorado Water ConservationBoard1313ShermanStreetDenver,CO80203(303) 866-3441STEINBERG,BoryU.S.ArmyCorps of Engineers20Massachusetts Avenue,N.W.Washington,DC20314-1000 (202) 272-0116

PAGE 250

SWANSON,JohnFEMA/RegionVIIIDenverFederal Center Building 710,Box25267Denver,CO80225-0267 (303) 235-4900TAYLOR,AlanCity of Boulder1739BroadwayPost OfficeBox791Boulder,CO80306(303) 441-3240THAYER,NonaFormerLarimer County Commissioner1827MichaelLaneFortCollins,CO80526(303) 482-7932THOMAS,WilliamE.LarimerCountyUndersheriff Post OfficeBox1190FortCollins,CO80522(303) 221-7102TOMS,EdA.Hydrologic Consulting Engineers4890RiverbendRoadBoulder,CO80301(303) 449-2113TRUBY,Jack Colorado Division ofDisasterEmergencyServicesCampGeorge West Golden,CO80123(303) 273-1779TUBBESING,SusanNatural Hazards Information CenterCampusBox482University of Colorado Boulder,CO80309-0482 (303) 492-6818TUCKER,DonnaF.Department of Atmospheric Science ColoradoStateUniversity FortCollins,CO80523(303) 491-8441TUCKER,L.Scott239UrbanDrainageandFlood ControlDistrict2480 West 26thAvenue,#156-BOenver,CO80211(303) 455-6277TULLY,ThomasM.Synerget icsInternationa1,Inc.6565Odell Place Post OfficeBoxE Boulder,CO80306(303) 530-2020URICK,William,IIISynergeticsInternational,Inc.6565Odell Place Post OfficeBoxE Boulder,CO80306(303) 530-2020VAN WIE, DonSystems Concept of Colorado Post OfficeBox3171Boulder,CO80307(303) 447-8352WAGONER,RichardA.National Weather Service806013thStreetSilverSpring,MD20910(301) 427-7706WALKER,Bi11DenverPost650 15th-Sfreet Denver,CO80201(303)820-1010WALTS,Dennis National Weather ServiceNOAA/ERL/PROFS325BroadwayBoulder,CO80302(303) 497-6561WHEELER,RobertL.PublicWorksandUtilitiesCity ofBou1der1739BroadwayPost OfficeBox791Boulder,CO80306(303) 441-3200

PAGE 251

WHITE,GilbertF.Instituteof Behavioral ScienceCampusBox482University of Colorado Boulder,CO80309-0482 (303) 492-6311WILLIAMS,DouglasJ.Greenhorne&O'Mara, Inc.3131SouthVaughnWay#228Aurora,CO80014(303) 755-9000WRIGHT,JamesM.Tennessee Valley Authority200Liberty Building Knoxville,TN37902(615) 632-4792WRIGHT,KennethR.Wright Water Engineers, Inc.2490West26th Avenue,Suite55ADenver,CO80211(303) 480-1700WRIGHT,RuthColoradoStateLegislature1440HighStreetBoulder,CO80302(303)866-2904 or 443-8607

PAGE 252

241APPENDIXIISUPPLEMENTALBACKGROUNDINFORMATIONWHATPEOPLEDIDDURINGTHEBIGTHOMPSONFLOODEveC.GruntfestAccordingtoseveralofthedeputiesandhighway patrolmenwhoissuedwarnings, mostofthepeople intheBigThompsonCanyononJuly31, 1976, were not warnedofficiallytoevacuate.Theperson-to-personwarningconcentratedontheareaatthemouthofthecanyon.Twopatrolmen wereinthevicinityof Draketryingtokeeptrafficfromtravellingupthecanyonandtoencourage peopletoclimbtohigherground.Anaccount ofthetypesofwarningsissuedwillshedsomelightonthesituationpriortoflood impact.TheColoradoStatePatrolinEstes Park receivedwordoftraffictie-upsinthecanyon around 7:30pm.Thiswasnot unusualforaweekendevening.Thepatrolman wenttocheck outtheproblem 7.5 milesdownthecanyon,andreportedontheradiothatthereweretrees,mud,androcks blocking U.S.Highway34. Followingan8:45pmmessage of floodingfromthepatrolman near Estes Park,theLarimer CountySheriff'sDepartmentandtheColoradoStatePatrolbeganintensivewarnings of campgroundsandmotorists.Atthattime,thepatrolman advisedthatwarningsbeissueddownthecanyon.Atthelowerendofthecanyon, whereitwasnotraining,itseemedhardtobelievethata floodwaspossible.EvensomeofthedeputieswhowereresponsibleforwarningothersthoughttheOlympusDamnear Estes Park must have broken inordertocause aflashflood.(Itheld throughtheflood,thoughthebasesufferedsomeerosionduringthestorm.)Several milesupthecanyon,justtothewestoftheNarrows,thecommunityofCedarCovesitsbelowtheroadandadjacenttotheriver.This areareceivedwarningsfromasheriff'sdeputy, a highway patrolmanwholaterlosthislifenear Drake, amemberoftheLovelandpolicedepartment,andaprivatecitizen.Tenpeople wereattheCoveredWagonCafejustonemile west of Cedar

PAGE 253

242Cove.Thecustomersfinishedtheirmealandstartedupthecanyon.Whenrockslidespreventedtheirpassage throughtoDrake,theyreturnedtotherestaurant.Onewaitresshadbeensenthomeearlybecausethebridgeleadingtoherhomeacrosstheriverwasnotoriouslylow.Theproprietorthoughtitwiseforhertogethomebeforethewater rosetoohigh.Thepeople intherestaurantdid notreceiveanofficialwarning, butthewaterwasrisinginfrontoftherestaurant.Everyonemovedtotheproprietor'shouseadjacenttotherestaurant.Whenthewaitresswholeftearlyreachedherhome,shecalledtherestauranttotellthemshewassafe.While shewasonthephone,theproprietor'shomeandrestaurantwere washedaway.Allwhowereinthehomewere swepttotheirdeaths.AttheCanyonInn near Cedar Cove, approximately20people,includingemployeesandguests,were conversing abouthowslowbusinesswasthatnight.Noonehadanexplanationforthisuntilreportswere receivedthatlandslideshadoccurred west oftherestaurant.Atapproximately 8:30pm,asheriff'sdeputycameintotherestauranttowarnpeople ofrisingwaterandpossibleflooding.Heinstructedthemtocrosstheriverandclimbupthemountainside.Thepeople tooknoactionin responsetothiswarning.TwentyminuteslaterhereturnedwiththemessagethatthedamatEstes Parkhadbrokenandthepeopleintherestaurantshouldcrosstheriverandclimb immediately. People did respondtothissecond warning.Somedrove out ofthecanyon, andothersclimbed asinstructed.Thewaterwasthreeandonehalffeetdeep intherestaurantsoonafterthewarning.Someperceivednodanger from aflashflood warning,yetresponded quicklytothemessagethatthedamatEstes Parkhadbroken. Thisadaptiveactionmaybelinkedtotheextensivemedia coverage oftheTetonDamcollapsein Idaho,fiveweeksbeforetheBigThompsonflood.Onesheriff'sdeputy involvedintheissuanceof warningsexplainedhowpatrolcarscircledtwoorthreetimesin one campground with loudspeakers.Somepeople responded immediately,includinga couplewhorememberedtheRapid City flood of 1972. Others responded followingthesecondandthirdwarnings.Atleasttwopeople did notmovefromtheircampingspotandwereamongthevictims.Drake,attheconfluence oftheNorth ForkandtheBig Thompson,washithardestbytheflood.For most peoplethere,theonly warningscamefromenvironmental cues:theriverrising,theseverityoftherainfall,or a change

PAGE 254

243inthesound oftheriver.Onestatepatrolmanwhowasnotifiedoftheproblem causedbyrisingwater west of Drake advisedseveralpeopleatDraketodrivedownthecanyonratherthantrytodriveup.Hehadnoideawhattheeventual impact oftheflood downstreamwouldbe.Itisnotknownhowmanypeople didtrytodrivedownorwhathappenedtothem. A highway patrolmanhadbeen watchingtheOlympicsontelevisionwithhiswife in Estes Parkwhenheheard aboutpotentialrockslidesfromthedispatcher.HedrovetoDraketoevaluatethesituation.At9:00hereporteda suddenriseintheriverandtoldtheStatePatroltowarnthepeople of LovelandandthoseeastoftheNarrows.Fifteenminuteslaterthedispatcherin Greeley recorded Purdy'sfinalreport,"I'mstuck,I'mrightinthemiddle ofit,Ican'tget outabout ahalf-mileeastof Drakeonthehighway. Tellthemtogetout ofthatlowareadownbelow.Andas soon asthewaterstartspickingup(static)high ground"Thedispatchertriedtorecontacthimwithoutsuccess.Later,Sergeant Purdy'sbodywasfound hiscarremained whereitwas, crushed under aslideofmudandrock(McComb,1980, p.20).Onecouplehewarnedwasreturningfromanevening in Estes Park.Theythoughthewasexaggeratingtheseriousnessofthesituationwhenhetoldthemtoget out oftheircarandclimb.Theydiedintheflood.AtleastonecoupleatWaltoniahaddeveloped a personal contingency plan intheeventthatthedamatEstes mightonedayfail.Theywere so accustomedtotheusual soundandheightoftheriverthatas soon asthesoundnoticeablychanged,theyrespondedtothisenvironmental cueandclimbedthemountain. Sixteen people diedintwoseparatemotelsatWaltonia.Theonly warning reportedwasanunofficialonefroma motel manager.Somepeoplemanagedtoescapedownthecanyonincars;othersclimbedupthemountainside.Detailsofthesituationin Waltoniaaredifficulttoascertainsinceneitherthemotel owners northeirfamiliessurvivedtheflood.IntheCedarmontand7 Pines area nearGlenComfort,nowarnings werereportedtohave beenreceived.Atone ofthefour motelslocatedinthisarea,a familyhadjusttaken aroom.Becauseitwasrainingsohard,themanagerinvitedthefamilyinsideforcoffeeandcookies.Theyacceptedtheinvitationandlefttheirbelongings inthecar,planningtomoveintotheirroomwhentherainletup. This familywasintheBigThompsonCanyononly

PAGE 255

244because they could notfinda motelroomin Estes Park.Astheyconsumedthetreatsprovidedbytheproprietorofthemotel,therivergot louder andseemedtobegettingcloser.Aftera coke machinefloatedbyandwater began seeping underthedoor,thefatherinthefamily decideditwastimetomovertohigherground.Theonlystepstotheupstairsportionofthemotel wereontheoutsideofthebuilding.Sincehecould not getoutsidesafely,hecuta hole inthesheetrockceilingandthewoodfloorabove.Hisfamily,andthatoftheproprietor,climbed out ofthemotel.Theyspenttherestofthenightonthemountainside.Themotelwasnot washed away, butthewaterrosefourfeetandthedamagetothebuildingexceeded50%ofitstotalworth.At7 Pines Motel,sixmilesfromEstes Park,twopeoplefromOhio were camping.Earlierthatdaytheirtireneededfixing,andone ofthecampershadjustreturnedfromLoveland wherehehaditrepaired.Itwasrainingso hardthattheymovedtheircamping gearintothecarandsatlisteningtotheradio.Whenthecarbeganfloatingaway, they wereabletomoveittohigherground withconsiderableeffort.Whentheychecked with a nearby moteloffice,themanagersentthembackdowntowardtherivertotrytorescuetwoyoungwomeninastreamsidecabin.Inordertogettothecabin,theyhadtocrossalowflatarea.Whentheysawa wall of water rushingdownthecanyon, they clungtoa nearbycar.Whenitbeganfloatingaway, they grabbed a shrub whichalsowasunderminedbythewater.Theywere holding onto a pinetreewhenthecabinwassweptaway.Oneoftheyoungwomenmanagedtoget outofthecabinandheldontoatreedownstream;theotheronewascrushed inthecabin.Thetwoyoungmensurvived.A busload of campersandavanfromacampoutsideEstes ParkwasreturningfromatriptoCheyenneFrontierDays. Therewasanairof excitementonthereturntripsincea dancewasscheduled.Thegroup stoppedatthepowerplantparkfora quickdinner;thentherainbegan.Afterdinnerthetwovehiclesheadedupthecanyon:onewentupRoute 34,andtheothertookthenorthforkroute.Neithervehiclegot veryfar;theirprogresswasblockedbyfallentrees,blindingrain,stoppedcars,andbouldersontheroad.ThetwovehiclesmetinDrakeanddecidedtodrivebackdownthecanyonandbacktocampviaLoveland.Theymusthave escapedjustsecondsbeforethenumerouslessfortunatecarsandtheirdriverswere swept away.Manypeople were extremely lucky, abandonningtheirautomobilesatthelastsecond.Onegroup

PAGE 256

245saidtheyhadfourflattiresandtheroadwasblocked beforetheygot outandclimbedthehillside.Imaginetheviolence theymusthave beendrivingthrough before theyfinallyescapedtohigh ground. Throughouttheevening,manytouristsdrivingthroughthecanyonmetwithlandslidesandrockfalls.Someturned backtoEstes Park or Loveland,andothersabandonedtheircarsandclimbedthecanyonwall.Thoseinthelattergrouphadthebestchanceforsurvival.Whenone hearsofthenumberofclosecalls,peoplewhoescapedatthelastsecond,itisincrediblethatthedeathtollwasnothigher.LANDACQUISITIONINTHEBIGTHOMPSONCANYONFOLLOWINGTHE1976FLOODCaroleHuberFollowingthe1976flood,SteveMcMillanoftheFlood RecoveryOfficeidentifiedlandmostsusceptibletoflooding alongtheBigThompsonRiver.Theowners oftheseidentifiedflood-proneparcelswere giventheoptionofsellingtheirland.Thedecisiontosellwascompletelyvoluntary;nopressurewasappliedtoland owners.Theidentificationprocess tooksixmonths,anditwasanadditional12months before Larimer County completedthepurchase ofparcels.ThelastForest Serviceacquisitionwasnot completeduntil1981.Theidentifiedparcelsconsistedof both undeveloped landandlandonwhichownerswere not allowedtorebuildbecausedamagetotheirhomesexceeded 50% oftheirvalue.Approximately30homeownerswere allowedtorebuildwithinthe100-year floodplainbecausetheirhomessufferedlessthan than 50% damage.Inaddition,thecounty'sFloodReviewBoard grantedthreevarianceswhichallowedreconstructioninthe100-year floodplainofhomesdamagedin excess of 50%. Propertywasappraisedandpurchasedatpre-floodvalues.Themajorityof landwaspurchasedbytheLarimer County Parks Department.AcquisitionsbytheParks Departmenttotaled124parcelspurchasedfrom98property ownersatacostof $1,547,771. Twenty-nine owners chose nottosell34parcels,theappraised valueofwhichtotaledmorethan $175,000.Fiftypercentofthe

PAGE 257

246moneyforacquisitionbytheParks DepartmentwasobtainedfromtheColoradoStateGeneral Fund,theFour Corners Regional Commission,andLarimer County.Theremainingfiftypercentconsistedof matching fundsfromtheLandandWater Conservation Fund.TheUnitedStatesForestServicealsopurchased flood-pronepropertiesintheCanyon,themajorityalongtheNorth Fork oftheBigThompsonRiver. Twenty-fourparcelstotaling956.08acreswere acquiredbytheForestServiceatacostof $860,533.Twelveowners chose nottoselltheirpropertytotheForestService.A board ofCanyonresidentsidentifiedsuitablepark landfromtheparcelsthattheLarimer County Parks Departmenthadpurchased. Basedonlocationandaccessibility,nineareaswereidentifiedassuitableparksites.Ofthesenineareas,threewereselectedtobedevelopedintoparks.Thesethreeparks --The Narrows,Fork'sParkandSleepy Hollow--were developed between1981and1984atatotalcostof $69,822(ofwhichhalfwasreturnedtotheCountybytheLandandWater Conservation Fund),andaremaintainedatanannualcostofapproximately $12,000.Atpresent,therearenoplanstodevelopanyoftheotheracquiredparcels.

PAGE 258

LARIMERCOUNTYLANDACQUISITIONINBIGTHOMPSONCANYONNo.ofNo.ofAREAParcel s PropertyOwnersAppraised CostAreaNo.1 5 3 $ 90,700AreaNo.2 0 0-0-AreaNo.3 3 3 78,800AreaNo.4 0 0-0-AreaNo.4a1 1 29,300AreaNo.5 8 3 7B,800AreaNo.61713159,960AreaNo.7 2 1 28,500AreaNo.8 2 2 42,000AreaNo.9 3 3 28,860AreaNo.10146 113,200AreaNo.112 2 31,690AreaNo.12a1211160,300AreaNo.12b2321203,450AreaNo.13(ForestServoAcq.)0 0-0-AreaNo.146 6 101,810AreaNo.15(Forest Serv.Acq.) 0 0-0-AreaNo.162 2 71,000AreaNo.17108 176,070AreaNo.1800-0-AreaNo.18a1 1 7,760AreaNo.19(Forest Servo Acq.) 0 0-0-AreaNo.19a0 0-0-AreaNo.204 477,141AreaNo.20a3 3 12,600AreaNo.211 1 6,300AreaNo.221 1 13,430AreaNo.233 2 33,100TOTALS*:12397$1,544,771 *Pursuanttothecompilation ofthesefigures,anadditionalpurchasewascompleted, bringingthetotalacquisitionbyLarimer Countyto124parcelspurchasedfrom98propertyownersatatotalappraisedcostof $1,547,771.

PAGE 259

Nt 2Land Acquisition Areas '-t GrantedI (Structures arepre-1976) mi. LarimerCounty Varianceso '7T I. -'-\ /\ :Q__l -L-uf __.1THOMPSONCANYON(EAST)BIG (D .. @:@a()-

PAGE 260

(Structures are pre-1976)LorimerCounty Land Acquisition Areas @@ Variances Granted012I I"II

PAGE 261

BIGTHOMPSONFLOOD:DRAKEARE/\.July 31,1976 100-200---300APPfUlI Scaler200'LEGENDPhysic." ;;-_ .Extent of floodwaters River courseas01 Aug. 3.1976 :-..:.:-.:. River courseasot Aug. 29. 1973Structur.1: BUlldlrlgs removed by lIaading or bymanlaler rzzzJ Buildings suffering severe damage byflooding:lulUlestatusunknown_ BUIlding receIVIngmmimalor no damage BrIdges. highway destrOyed by Hood =Bridges. highway Intact ConlpllallOnand CarlorJJaphy by G')orgc Salvador. JarnesSllanerSOUICC HoganI PC ACllal PhotosFigureA-3.. , l:J

PAGE 262

o It o

PAGE 263

252APPENDIXIIIABSTRACTSDFPAPERSNOTINCLUDEDINPROCEEDINGS1)ADECADEOFPROGRESSINFLOODWARNINGANDRESPONSECurtisB.BarrettOfficeof HydrologyNOAA/NationalWeather Service Inthepasttenyears,therehas beensignificantprogressintheimprovementofflashflood warningandresponse.MoreFederal,state,localandprivateofficialsareawareofthepotentialfora majorflashflooddisaster.TheFederalEmergencyManagementAgency(FEMA)has determinedthatthereare20,000 communitiesvulnerabletoflashfloods.Ofthese20,000 communities, over 17,000nowsubscribetotheFlood Insurance Program.Manyofthesecommunities have takenstepstomitigateflooddamagesthrough improved flood warningandresponse systems. Thereareover 65,000damsintheUnitedStates.AccordingtotheInteragency CommitteeonDamSafety,10,000 ofthesedamswouldcause a majorcatastropheiftheyfailed.Approximately 3,000damsareunsafe.ManyFederal,State,andprivateownersaretakingstepstoreducetheriskofdambreaks.Thepastdecade, a combination ofnewtechnologyandsignificantreductionsincostof microcomputers hasresultedinthedevelopmentandimplementation of automatedlocalflood warning systems.Currently,thereareover200communitiesutilizingstate-of-the-artautomated systems. Thisincreaseddemandforflood warningservicehas causedmanyFederalandStateagenciestoincreasetheirroleintheflood warningeffort.Therearenowfivevendorsactivelyinvolved intheestablishmentof automated flood warning systems.TheNational Weather Service hassignificantlyimprovedtheabilitytoforecastanddetectflashfloodevents.Theestablishmentof a 24-hourunittoforecastheavyrain(quantitativeprecipitationforecasts,orQPF)has provided advancedalertingof heavyrainfallinmanycases.Theenhanced use ofsatellitestoestimateheavyrainfallforconvective

PAGE 264

253rainstorms has increased ourabilitytodetectflashflood producing thunderstormcells.TheNESDISSynoptic Analysis Branchutilizesaninteractiveflashflood analyzertomonitormanyareasforflashfloodpotential.ThesameGOESsatelliteusedtodetectrainfallvia imagery processingisalsousedtorelayrainfallandstreamflowdatacollectedfromremote datacollectionplatforms(DCP).There arenowover 2,000DCP'scollectingrainfalldata used intherecognitionof heavyrainfalleventsandatenfoldincreaseinthenumberofDCP'sisanticipatedoverthenext 5to10years.Tenyears ago,therewerelessthan 100.Still,flooddamagescontinuetoincreaseeachyearandpeople continuetoinhabitthefloodplain.Until asubstantialincreasein hydrologic sensors occurs,manycommunities will remain vulnerabletoflashfloodevents.2)PREPAREDNESSCANREDUCEBOTHRISKANDLIABILITYJohn PatByrneColorado Department of Public Safety Division ofDisasterEmergencyServices Althoughthemagnitudeandtiming offlashfloods cannotbepredictedwithprecision,theirlocationsandrelativefrequencies canbeidentifiedfromthehistoricalrecord.Theriskoflossforthosevulnerabletotheseevents canbereducedbyactingonavailableinformation.Similarly,theobligationsof governmenttoincreaseawareness of exposure,warnof occurrence,andreducedamagewherepossiblearebestmetbyinformedaction.Potentialcoststoboth groups canbereduced where preparednessisperceived as a sharedresponsibility.

PAGE 265

2543)METEOROLOGICALASPECTSOFTHEBIGTHOMPSONFLASHFLOODOF31JULY1976CharlesF.Chappell Weather Research Pro9ramNOAA/EnvironmentalResearchLaboratoriesDescriptionsofthemeteorologicalconditionsthatproducedthedevastatingflashflood intheBigThompsonCanyonon31July1976arepresented.Thestormdevelopedwhenstronglow-leveleasterlywindstotherearof apolarfrontpushed a moist,conditionallyunstableairmassupslopeintotheFrontRangeoftheRockyMountains. Orographicupliftreleasedtheconvectiveinstability,andlightsouth-southeasterlywindsatsteeringlevelsallowedthestormcomplextoremainnearlystationaryoverthefoothills.Minimalentrainment ofrelativelymoistairatmiddleandupperlevels,lowcloudbases,andaslightlytiltedupdraftstructurecontributedtoa highprecipitationefficiencyforthestorm. MeteorologicalconditionsthatproducedtheBigThompsonFlash Flood arequitedistinctfromthoseassociatedwithtypicalsummerthunderstorms overtheRockies. Thisfactishelpingmeteorologiststoidentifyasetof meteorologicalconditionsthathavethepotentialtoproduce excessiverainsovertheFrontRangewatersheds.4)FLASHFLOODFORECASTINGRESEARCHSINCETHEBIGTHOMPSONFLASHFLOODOF31JULY1976CharlesF.Chappell Westher Research ProgramNOAA/EnvironmentalResearchLaboratoriesTheoccurrence oftheBigThompsonFlood of31July1976hada major impactonresearchtounderstandandimproveforecastsofflashflood producing storms. This research has includedtheinvestigationofthesynopticandmesoscale environmentswhichproduce excessive convectiverains,as well asdetailedcasestudiesof individualevents.This research has ledtotherecognitionof several meteorologicalpatternswhichfavorthedevelopmentofflashflood producing storms overtheUnitedStates.Meteorologistsarenow

PAGE 266

255capableofidentifyingseveralhours in advance, withsomeskill,"watch"areaswhereexcessiverainsandflashfloodsmayoccur.Thisresearchisalsohelpingradarmeteorologiststobetteridentifyandmonitor inreal-timethosestorms withflashfloodpotential.Thisburstofresearchintoexcessiverainsandflashfloodforecastinghasalsospreadtoothercountries,wheresimilarresearcheffortshaveaccelerated.5)THEPOSSIBILITYOFDEBRISBULKINGOFTHEBIGTHOMPSONFLOODJ.ErnestFlackCivil,Environmental,andArchitecturalEngineeringUniversityof Colorado RecentresearchonmUdflows,debrisandmUdflooding in mountainousterrainhas demonstratedthatconcentrationsof sedimentandothermaterialinflood watersmayexceed80%byweight insomecases.InthispaperthepossibilitythattheBigThompsonflood of1976mayhave beenincreasedin bothvolumeandpeakduetoincorporationoferoded sedimentwillbeexplored.Asyntheticflood hydrographwillbedevelopedUSin9standardhydrologic techniques of convertingrainfalltorunoff usingtheobservedandestimatedprecipitationforthe1976stormevent.This hydrographwillthenberouted downstreamandthen bulkedbytheestimatedamountof sedimenterosionthatwasin suspension duringtheflood.Thisestimateoferosionwillbebasedonthearealanddepthestimatesof scourthatoccurred duringtheactualflood.Theresultingbulked hydrographwillbecompared withtheactualflood hydrograph(s) as developedbyvarioussources.This comparisonwillgivesomeindicationofthepossibilityofsediment bulkingincreasingthehydrographsforfloodsoccurringin mountainousterrain.

PAGE 267

2566)CHANGESINEMERGENCYPREPAREDNESSINTHEBIGTHOMPSONCANYONWilliamI.Gordon,DirectorOfficeof EmergencyManagementFortCollins,Colorado Study ofBigThompsonFlood ofJuly31,1976revealed aseriesof emergency preparedness problems,someof long-termnature,otherscoincidentalandtemporary--allof whichcontributedtotheexcessivelylargecasualtylist.Sincethattime,federal,stateandlocalemergency preparednessagencieshave addressed each ofthoseproblems with a view towardinsuringthatanyfutureevent would notsuffersimilarconsequences. Problem:Correction:Problem:Correction:Problem:Correction:Residences inthefloodplain.Floodplainregulationsadopted whichrestrictbuildingresidencesinthefloodway. Fundsobtainedtopurchase landinthefloodway whichotherwisemight have been usedforresidences.Highway,parallelingriverin a narrow canyon,waswashedawaybyrushing waters whichcarriedcarsandoccupants downstream.HighwayrebuilttowithstandlOO-yearflood.Major channel improvementeffort.Someresidentsandvisitors,unfamiliarwithcharacteristicsofflashfloods,refusedtoabandontheirhomesandcars,andmanyattemptedtodrivethrough floodwaters.Signs in approachestocanyonadvisingmotoriststoclimbtosafetyintheevent of aflashflood.Safeareasalong highwaysaredesignated.Familiaritywiththeeffectsofaflashflood has changedtheattitudeoflocalresidentsandtheyarenowfullycognizant of neededprotectivemeasures.

PAGE 268

Problem:correction:257Information aboutthepotentialfloodthreatwasnot disseminatedearlyenoughtowarnresidentsandvisitors.Contract with local weatherserviceandorganizationofspotters.Fulltimeemergency managerappointed--oncall24hours a day.Sheriff'sDepartment improved communicationsandcapabilities.Emergencyoperationsplan developedandexercised.Proof of success of oureffortswasrecognized duringLawnLakeFlood of 1982.7)FLASHFLOODFORECASTING:DEJAVU1976ANDVUJADE1986JohnF.Henz HenzKelly&AssociatesDenver, ColoradoIntheauthor'sopinion,theartofflashfloodforecastingwasalmostnonexistentin1976priortotheBigThompsonFlash Flood.Fewifanypapersexistedinthescientificliteraturedealingspecificallywithflashfloodorheavyrainforecasting.Interestinthesepredictionswasheightenedbythedeadly Rapid Cityflashfloodof1972.Theauthorwasinvolved in apost-stormanalysisofthisflashflood whileatColoradoStateUniversitywithProf.LewGrant,MikeFritschandVince Scheetz. Post-storm meso-analysis ofthisstormbyseveralgroups pointed outsomekeystormingredientsbuttheseanalysesstoppedshortof providing aforecastingscenariotobe appliedoperationally.Howeverthepost-stormanalysiswassufficienttoprompt a"dejavu"forecastoftheBigThompsonpotentialfouryearslaterinanoperationalsetting.Asthestorm'spotentialunfoldedandwasrealized,conventional hourlysurfaceobservations,typedradarobservationsorremoteradarfaxreports,and"aseasoned look outthewindow"providedthekeyshorttermforecastinginputs.Bywayofcontrast,thehigh-tech1980's have providedtheoperational

PAGE 269

258meteorologistwiththeimprovedinsightintoflashfloodforecastingaffordedbynumerousexcellentresearchpapers,post-stormanalysesandmethodologies.Additionallysignificantimprovements inthepresentationof weatherradar,satelliteandsurfaceobservationshaveassistedtheweatherpredictionproblem.Remoterain and stream gage systems can monitorrainfallandverifyforecaststhoughthesesystems have been oversold as warningtools.The"vujade"referstotheintegrationoftheseobservationalimprovements with high powered personal computersandoperationalpredictionmodelstoallow highlyreliableandaccuratepredictionsofflashflood occurrence beforetheevent happens.Theconsistentapplicationoftheseadvancesintheflashfloodpredictionprogram approach in Denver has ledtoahighlysuccessfulwarning program whichwasonly dreamt ofin1976. 8)SUCCESSFULFLASHFLOODFORECASTINGINCOLORADO1983TO1985JohnF.HenzandRonA.KellyHenzKelly&AssociatesDenver, ColoradoTheUrbanDrainageandFlood ControlDistrictestablishedaflashfloodpredictionprogram in responsetothedeadlyBigThompsonFlash Flood of1976in 1979. Recentsignificantflashflooding events which occurred withintheDistrictunderscoretheabilityoftheprogramtopredictandreliablywarncommunities intheDistrictofflashfloods.Results oftheoperationalpredictionoftheCherry Creek Flash FloodofJuly1983,theDenver Mega-Rain/Hail Storm of June 1984,theJuly19,1985South Suburban CloudburstandtheCheyenne Flash Flood of AugustI,1985willbepresented.Eachofthesestorm systemswasaccuratelypredicted3-6 hours beforethestormsformedwithtotalstormrainfall,peak storm hourlyrainfallintensity,stormtrack,duration,basin coverageandassociatedsevereweatherpredicted.Inallcasesappropriatelocalgovernments wereissuedtheforecastsbeforetheevent.TheCheyenne Flash FloodcaseisespeciallyinterestingsincetheDenver areawasalertedfora "Cheyenne-type" stormpotential6-8 hours beforetheflashfloodoccurred.TheDenveralertwas

PAGE 270

259droppedbylateafternoon asitbecameapparentthepotentialwasfocussingtothenorth.Theimplications ofthis"miss" willbediscussed.9)ROLEOFTHEMEDIAINTHEBIGTHOMPSONDISASTEROF1976Daryle W. Klassen LarimerCountyCommissioner Loveland, ColoradoSomepointstobediscussed duringthispresentationinclude:1.Mediamis-understandingsanddistortionsatthetime of thecatastrophe;2.Mediacontributionto the problemsathand; 3.Methodsof minimizingmediaproblems; 4.Mediacanbe,andwere, ofgreatassistancein problem solving;and5. economic impactsuponaffecteddisasterarea.10)ACLIMATOLOGICALVIEWOFLARGEPRECIPITATIONEVENTSThomasB.McKeeandDavidChangnonDepartment of Atmospheric Science ColoradoStateUniversity Severeprecipitationevents ineasternColorado, those producingdamagingfloods, occurontheaverage once every fouryears.Theclimatology of these largeevents,theelevationfactor,theprobabilityof aBigThompson-type stormatFortCollins,as well asothermethodsof climate estimatesarepresented. Storms centeredmostoftenonthe FrontRangeandPalmer Divide areas of Colorado producethelocalizedflooding conditions such asthatexperienced intheBigThompsonFlood of 1976.

PAGE 271

26011)PUBLICRESPONSEELEMENTSFORFLOODWARNINGEMERGENCYPREPAREDNESSDennis S. Mileti Hazards Assessment LaboratoryandDepartment of Sociology ColoradoStateUniversity A review of empiricalstudiesofhumanresponsetowarnings of impendingdisasterreveals asix-stepdecisionmakingprocessthatoutlineswhatcan leadtopublicprotectiveactionsin responsetothose warnings. Thesesixstepsare:hear,understand,believe,personalize,decideandrespond. Avarietyoffactorsthatcanbeincorporatedintoemergency preparedness for flood warnings enhancethisprocess,andtheseinclude warning sourcecredibility,informationconsistency,message accuracy, informationclarity,messagecertainty,level ofdetailin information, provision of guidance concerning response, warning frequency,clarityinrisklocation,andchannel of conveyance. This papersynthesizesthestateof knowledge regardingwhatpreparedness candotomaximizetheoddsofsoundpublic responsetowarnings of flooddisasters.12)HOWTHINGSHAVECHANGEDINFORECASTINGSINCE1976MauriceE.PautzAreaManagerfor Colorado National Weather Service Forecast Office Duringthelastdecade,significantchanges inforecasttechnology as well astheintroductionofnewtoolsfortheforecastertouse,have takenplace.Theuseandimpact ofnewnumericalforecastmodels willbediscussed.Improvedmethods of radardisplaysandsevere weatherdetectionaredetailed.Verysignificantchangesandimprovements insatellitedisplaysandinterpretationarediscussed.Advancesintheunderstanding of mesoscale weather systemsanduse of dense mesoscalesurfacedata networks are explained. Recentintroductionof remote sensing atmosphericprofilershaveaddedanewdimensiontotheoperationalforecastframework. Additional remote sensing intheformofDataCollection Platforms(DCPs)forthehydrologicandflashflood programshaverecentlybeenanadditionthatprovidestheoperational

PAGE 272

261forecasterwith approximately150sitesintheStateof Colorado for automatedriverstagereadingsandprecipitationvalues.Significantnewforecasttechnologyisontheimmediate horizon fortheNational Weather Service Forecast Office inDenverbythefallofthisyear.Anewworkstation forthePublic ForecastProgramwillutilizethelatesttechnologyasdevelopedbytheProgramfor Regional ObservingandForecasting Systems(PROFS)officeoftheEnvironmental Research Laboratories(ERL)in Boulder. This workstation will enable theforecastertotime-lapsevarious combinations ofradar,satellite,nesonetandconventional data inwaysheretoforenotavailabletotheoperationalforecaster.13)NEWDISASTERRESEARCHMETHODSINMENTALHEALTHANDTHEMOUNTST.HELENSSTUDYJamesH.Shore,M.D.Department ofPsychiatry,Schoolof Medicine University of Colorado Health Sciences CenterThemajor volcanic eruption ofMt.St.Helens in1980withanexplosion ofhistoricaldimensionandsubsequent floodsbecameanacuteandlong-termdisasterthreat.A researchmethodwasdeveloped inpsychiatricepidemiologythatincluded systematicdiagnosticcriteria(TheDiagnostic Interview Schedule), community-wide sampling inthedisasteranda control community, documentation oftheimmediateandlonger-termstressresponsepatterns,andanultivariantanalysis.Morethanonethousandsubjectswereevaluated.Thevariablesincludedpsychiatricadjustment, sociodemographiccharacteristics,past physicalandmental healthhistory,presentstatesymptomatology,interpersonalnetworks,andperception ofthedisasterstress.A high exposure groupwasidentifiedbyexternalcriteria.This high exposure groupshowedasignificantincreaseinpsychiatricmorbidity.Thefindings demonstrataed a step-wise dose responserelationshipthatsuggested a progression ofseverityfromcontroltolowtohigh exposuresubjects.

PAGE 273

26214)DAMAGESCAUSEDBYGEOLOGICALPROCESSESDURINGTHEBIGTHOMPSONFLOOD,COLORADO,1976,ANDSIMILARPASTSTORMANDFLOODEVENTSINTHECOLORADOFRONTRANGEJamesM.Soule Colorado Geological SurveyTheBigThompsonflood of1976causedconsiderabledamagesthroughout the area of heavyraninfalland/or flooding, both inthefloodplainsoftheBigThompsonRiveranditstributaries,andonvalleysideslopesoutsideof streamcourses.Manyofthesedamageswerecausedbymovementofsolidsbyrapidlymovingwaterandrapidmasswasting ofearthmaterialsonslopesoutsideoffloodplains.Afterthe1976flood,theColorado Geological Surveyandothersattemptedtocompareaftereffectsofanddamagescausedbygeologic processes intheBigThompsonareatoothersimilardrainagebasinsintheColorado Front Range. Current land-usepatternsinothercanyonsindicatethatsimilardisastersarepossibleintheotherareas.15)WEATHERFORECASTINGTOOLSFORTHE1990's Dennis Walts Office of Systems Development, National Weather ServiceandPROFSProgramOffice Durin9thelate1980'sandearly1990's,theNational Weather Service(NWS)willbeunder90ing a major pro9ramtomodernizeitsfieldoffices.Thiseffortisdesi9nedtoenabletheNWStoprovidebetterforecastsandearlierwarnings for mesoscale weatherphenomenasuch astheBigThompsonFlood event.Attheheartofthismodernization pro9ramisthedevelopmentanddeployment oftwosystems:NEXRAD(NEXtgenerationRADar),a nationwide network ofsophisticateddoppler weather radarsandAWIPS-90(AdvancedWeatherInteractiveProcessingSystemforthe1990's),a systemforreal-timeingest,processing,anddisplayof meteorological datafromavarietyofsources.A functional prototype offutureAWIPS-90workstationsisbein9 developedbytheProgramforRegional ObservingandForecasting Services(PROFS).On

PAGE 274

263October1,1986thisworkstation willbeplacedintooperation intheDenver, Colorado Weather Service Forecast Office(WSFO).Itwillbeusedtosupportthepublicforecastandwarnin9responsibilitiesoftheDenverWSFOonanaround-the-clockbasis.This will providethefirstopportunitytooperationallyevaluate a subset of bothAWIPS-90capabilitiesandNEXRADproducts. Thisproject,theDenverAWIPS-90Risk ReductionandRequirements Evaluation, willalsoprovidetheNWSwiththeinformation necessarytoplanthedevelopment ofthesystemtobeused throughtheyear2000. This paper providesdetailsofthenewcapabilitiesprovidedtotheforecaster,andexplorestheeffectsofthesecapabilitiesontheforecastandwarning process.

PAGE 275

264APPENDIXIVBIBLIOGRAPHYAlbertson, M.L.,M.Porch,andG.Hurst1978"Bi9ThompsonFloodDamageWasSevere, butSomeCouldHaveBeenPrevented." Civil Engineering(February),pp. 74-77. Balke, E.C.1977"BigThompsonRiver, Colorado, TotalPrecipitationforJuly31 August2,1976." National WeatherService,September. Balog, J.D.1978"Flooding inBigThompsonRiver, Colorado,Tributaries:ControlsonChannel ErosionandEstimates of RecurrenceInterval." 6(April),pp. 200-204.1976BiyThomsponRiverTributaries:GeomorphicActivityandItsControllingFactors During1976Storm." Boulder: UniversityofColorado,M.S.Thesis.Berling,R.1977"DisasterResponsetoa Flash Flood." American Society of Civil EngineersPreprint#2987, October.Bielicki,D.E.197B"Estimation ofBigThompsonFlood Rainfall UsingInfraredSatelliteImagery." Atmospheric Science Paper #300. FortCollins:ColoradoStateUniversity,December.Bolin,R.C.1982Long-TermFamily RecoveryFromDisaster.EnvironmentandBehaviorMonograph#36. Boulder:Universityof Colorado,InstituteofBehavioral Science. Boudoures,A.1977RadioStationResponsetoDisaster:ANewRole Emerges. FortCollins:ColoradoStateUniversity,M.S.Thesis,August. Burns,R.1977"Bridge Inventory,BigThompsonCanyon, Colorado." LarimerCountyPlanning Department, January.1976"ASummaryof PresentandAnticipatedLandUseRegulations Dealing with Redevelopment oftheBigThompsonCanyon." Larimer County Planning Department, October. Caracena,F.,R.Maddox,R.Hoxit,andC.Chappell1979"MesoanalysisoftheBigThompsonStorm." Monthly WeatherReview107(January),pp. 1-17.

PAGE 276

265Changnon,S.A.,Jr.,C.Ackermann, F. White,J.Ivens,et.al.1983A PlanforResearchonFloodsandTheirMitigationintheUnitedStates.Final ReporttotheNational Science Foundation. Champafgn:-rTlinois StateWaterSurvey, March. Charney,M.1980"OrganizationandOperation of a Temporary Morgue."ThePolice XLVII(April),pp. 66-67.1978"TheTemporaryMorgueandtheIdentificationofBodies."ThePolice ChiefXLV(October), pp. 285-288. Charney,M.AndC.Wilbur1980"TheBigThompsonFlood."TheAmerican Journal of Forensic tiedi I (#2),PP:--I39-144;--Cochrane, H.,M.Stokes,H.Burgess,andM.Steinbeck1979"TheBigThompsonFlood, ACaseStudy." Proceedings of ConferenceonEmergencyPreparedness, Western Governors' PolicyOffice.Denver, Colorado. Colorado Division ofDisasterEmergencyServices1982Colorado'sVulnerabilitytoVeryHighRisk Natural Hazards, Revised.GoI den. Colorado Water ConservationBoard1985Flood Hazard Mitigation PlanforColorado. Denver,CO.1983Colorado Floodproofing Manual. Denver,CO.1981"Colorado Flood AwarenessDay;July31, 1981."PublicityPacket.Cotten,D.(editor)1976The Big ThompsonFlood, July 31, 1976. Lubbock, Texas: C.F. Boone,Publisher.Doehring, D.O.,R.U.Grozier,andJ.M. Soule1976TheBigThompsonFlood of 1976: AFieldTrip Guidebook. Boulder, Colorado: Geological Society of America.Downing,I.E.1977aFlash WarningRecommendationsforFrontRangeCommunities. PreparedfortheUrbanDrainageandFlood ControlDistrict.Boulder: UniversityofColorado,Instituteof Behavioral Science,July.1977bWarningforFlash Floods in Boulder, Colorado. Natural Hazards ResearchWorklng Paper #31. Boulder: UnlveFSfty of Colorado,Instituteof Behavioral Science. FederalEmergencyManagementAgency1983Intergovernmental HazardMitigationReportfortheStateof Utah, in responsetotheApril 30, 1983,DisasterDeclaratlon,August. Denver.

PAGE 277

266FederalEmergencyManagementAgency1982LawnLakeDamFailure&Fall River Flood. InteragencyPost-DisasterMitigationTeamReport. Denver. 1981a 1981b Evaluation ofAlternativeMeansof Implementing Section1362oftheNational Flood InsuranceActof 1968. Washington,DC.Handbookof ProceduresforFloodDisasterMitigationPlanning: CaseStudies.Washington,DC.1981cHandbookof ProceduresforFlood HazardMitigationPlanningfortheInteragency HazardMitigationTeam.Washington,DC.Ferrell,W.R.andR.Krzysztofowicz1983"AModelofHumanResponsetoFlood WarningsforSystemEvaluation."Water Resources Research19(December), pp. 1467-1475.FieldAssociates,Inc.1979Profilesof Communities with Floodplain Westport,Connecticut.GingeryAssociates,Inc.1976d Hydrology Study:BigThompsonRiverandTributaries,Larimer CountyAboveLoveland, Colorado. Englewood, Colorado, October. 1976b Special FloodPlainInformation Report:BigThompsonRiverandTributaries,Larimer County-;-COloraa:o:Englewood,Colorado-, December.Glelck,1985J."They're GettingBetterAboutPredictingtheWeather (Even Don't BelieveIt)."TheNew limes Magazine (January 30-40.ThoughYou27),pp.Graham,1982 W. andC.Brown"TheLawnLakeDamFailure:ADescriptionoftheMajor Flooding EventsandanEvaluation oftheWarningProcess."PreparedforBureau of Reclamation,Divisionof PlanningandTechnicalServices,EngineeringandResearchCenter.Denver, Colorado.Grozier,1976R.U.,eta1.TheBigThompsonRiver Flood ofJuly31-August1,1976, Larimer County, Colorado. Flood Information Report. Denver: U.S. Geological SurveyandtheColorado Water Conservation Board, October.Gruntfest,EveC.1986"WarningsforFloods with ShortLeadTimes." Pages 81-88inFlood Hazard Management:BritishandInternationalPerspectives.Norwich, England:GeoBooks.1981Changes in FloodPlainLandUseandFlood Hazard: Adjustment in DenverandBoulder,CO,1958-1979. Boulder:UniversityofColorado, Department of Geography, Ph.D.Dissertation.

PAGE 278

267Gruntfest,EveC.1977WhatPeopleDidDuringtheBigThompsonFlood. Natural Hazards ResearchWorkingPaper #32. Boulder:UniversityofColorado,Instituteof Behavioral Science.Gruntfest,E.C.,T.E.Downing,andG.F. White1978"BigThompsonExposesNeedforBetterFlood Reaction SystemtoSaveLives."Civil Engineering(February),pp. 72-74. Haas,J.E.,R.II. KatesandM.J.Bowden(eds.)1977Reconstruction FollowingDisaster.Cambridge,MA:MITPress.Henz,J.,V.Scheetz,andD.Doehring1976"TheBigThompsonFlood of1976in Colorado." lIeatherwise (December),p.278.Hill,J.C.andR.J.C. Burnash1986"ALERT(Automatic Local Evaluation inRealTime)inSanDiego-QuantumLeapin Storm Warning/DataCollectionSystems." Paper presented inLasVegas, March. Hydrology Subcommittee oftheFederal Interagency Advisory CommitteeonWater Data1985"GuidelinesonCommunityLocal Flood lIarningandResponse Systems." Reston,VA:U.S. Geological Survey.Ilinitch,R.C.andM.Titus1977"Caretakers as Victims:the Big ThompsonFloodof1976." Northampton, Massachusetts: SmithCollege,M.S.Thesis.InterfaithTaskForce1977AftermathACitizens'Survival Journal 1(#3).Loveland,Colorado,Spri ng. James,J.,J.Kreger,andR.D.Barrineau FactorsAffectingPublic AcceptanceofFlood Insurance in Larimer andWeldCounties, Colorado. Information Serres #24. FortCollins:ColoradoStateUniversity,WaterResources ResearchInstitute,Jarrett,1984R.D.andJ.E.Costa Hydrology, Geomorphology,andDam-BreakModelingoftheJuly15, 1982,LawnLakeDamandCascadeLakeDamFailures,Larimer County, Colorado.Open-File Report #84-612. Reston,Virginia:U.S. Geological Survey. Kimball, E.H.1978RecoveryoftheOlder Survivors ofthe1976BigThompsonFlood. FortCollins:ColoradoStateUniversity,M.S.Thesls.Kleher,1976J.andM.Gifford StreamFlowAnalysis oftheBigThompsonFlood. FortCollins:ColoradoStateUniversity,Department of AtmosphericSciences,M.S.Thesis.

PAGE 279

268Kusler,1982J.A.,RegulationofFlood Hazard AreastoReduceFlood Losses,Volume 3. Natural Hazards ResearchandApplicationsInformation Center SpecialPublication#2. Boulder:Universityof Colorado,Instituteof Behavi oraIScience,Larimer County Mental Health Center1976"StaffDebriefingSession."Loveland, August.LycomingCounty Planning Commission1985"BePrepared -ACitizen'sGuideforFlood Evacuation." WilkesBarre,Pennsylvania.Maddox,1977McCain,1979R.A., F. Caracena,andC.F. Chappell Meteorological Aspects oftheBi9ThompsonFlash Flood of31July,1976.NOAATechnical Report #ERL388-APCL41. Washlngton,DC:U.S. GovernmentPrintingOffice.J.F.eta1.StormandFlood ofJuly31-August1,1976inthe RiverandCacheLaPoudre RiverBasins,LarimerandWeldCounties,Colorado. U.S.Geological SurveyProfessionalPaper #1115. Washington,DC:U.S. GovernmentPrintingOffice, IkComb, D.G.1980BigThompson:Profileof a NaturalDisaster.Boulder, Colorado:PruettPublishing.1976"Oral HistoryInterviewwith JimDooney:BigThompsonDisaster."August 19.Miller,J.A.1977Families intheAftermath ofDisaster:TheBigThompsonFloodof1976." FortCollins:ColoradoStateUniversity,M.S.Thesis.Miller,L.,D.MosesandM.LaCelle1976"Caregivers as Hidden Victims:StaffReactiontotheBigThompsonFlood." Larimer County Mental HealthCenter,StaffReports. Muller, L.A.,andP.F. Mulhern1977"1976 BigThompsonFloodandFlood RecoveryPlanning."CivilEngineering (November). pp. 34-41. National Advisory CommitteeonOceansandAtmosphere1983TheNation'sRiverandFloodForecastingandWarningService,a Special ReporttothePresldentandCongress. Washlngton,DC,March. National OceanicandAtmosphericAdministration(NOAA)1985GuidelinesonLocal Flood WarningandResponse Systems.SilverSpring,Maryland: U.S. DepartmentofCommerce.

PAGE 280

269National OceanicandAtmospheric Administration(NOAA)1981ALERT(AutomaticLocalEvaluation inRealTime). PreparedbyHydrologic Services DivIsIon fortheNatIonal WeatherService.1976BigThompsonCanyonFlash Flood ofJuly31-AugustI,1976, areporttotheAdministrator. NaturalDisasterSurvey Report #76-1.SilverSpring, Maryland: U.S. Department ofCommerce,November.National Science Foundation1980A ReportonFloodHazardMitigation.Washington,DC,September.Owen,H.J.1982"FloodWarningSystem;DoesYourCommunityNeedOne?"Prepared for National Weather Service. Palo Alto,California:FloodLossReduction Associates, October.1979"InformationforLocalOfficialsonFloodWarningSystems." Prepared for National WeatherService.Palo Alto,California:FloodLossReduction Associates,May.1977"Guide for FloodandFlash Flood Preparedness Planning." PreparedforNOAAandNWS.Palo Alto,California:FloodLossReduction Associates,May.Perry,R.W.andA.H.Mushkatel1984Disaster WarningResponseandCommunityRelocation. Westport, Connectlcut:QuorumBooks.Phillipsborn,R.H.1978"IntheAftermath of theBigThompsonFlood:HazardPerception in aParallelCanyon."EcumeneX(April).EastTexasUniversity.Commerce,Texas.Platt,R.H.1984aMetropolitan Regionalism: ImplicationsforFloodLossReduction.WorkingPaper #11. Amherst: University of Massachusetts,LandandWater Policy Center.1984bFloodandFederalism:TheLimits of Conventional Response.WorkingPaper #10. Amherst: University of Massachusetts,LandandWaterPolicy Center.1980IntergovernmentalManagementof Floodplains. EnvironmentandBehaviorMonograph#30. Boulder: University of Colorado,Instituteof Behavioral Science.1979OptionstoImproveFederal Nonstructural ResponsetoFloods. Consultant Report. Washington,DC:U.S. Water Resources Council, December.Platt,R.H.andG.M.McMullen1978Post-Flood RecoveryandHazardMitigation:LessonsFromtheMassachusetts Coast. PubJlcatlon #115. Amherst: Unlverslty of Massachusetts,WaterResources Research Center.

PAGE 281

270Rahn,P.H.1984"FloodplainManagementProgram in RapidCity,South Dakota." Geological Society of AmericaBulletin95(July),pp.838-43.Rubin,1985Clai reB.etal.CommunityRecoveryfroma MajorDisaster.EnvironmentandBehaviorMonograph#41.Boulder:Universityof Colorado,Insituteof Behavioral Science. Saarinen,19821.F.(ed.)PerspectivesonIncreasing Hazard Awareness. EnvironmentandBehaviorMonograph#35.Boulder: Universlty of Colorado,Instituteof Behavioral Science. Shelton,D.C.andD.Prouty1979Nature'sBuilding Codes--GeologyandConstruction in Colorado. SpecialPublication#12.Denver: Colorado Geologlcal Survey.Showdy,1980H.MTheNational Flood Insurance Program intheLarimer County, Colorado Area. InformationSeries#44.FortCollins:ColoradoStateUniversity,WaterResources ResearcllInsLitute.Simons,D.B.etal.1978Flood of31July1976inBigThompsonCanyon, Colorado. National Research Council. Washington,DC:NationalAcademyPress Soule,1976J.M.andW.P.Rogers Geologic Hazards, Geomorphic FeaturesandLandUseImplications intheAreaof til" 1976BigThompsonRiver Flood. Environmental Geology Report#10.Denver: Colorado Geological Survey.ToupsCorporation1977BigThompsonDisasterRecovery Planning Report, Vols.1-6,November.U.S.Army1977 1976Corps of Engineers FloodPlainInformation:BigThompsonRiver, LovelandtoLarimer-Weld County Line, Colorado:LittleThompsonRlver, BoulderandLarimer Counties, near BerthOUd, Colorado.Omaha,Nebraska, June. "Post-Flood Report,BigThompsonRiver, Floodof31July-lAugust1976."Omaha,Nebraska: December. U.S. Water Resources Council1986A Unified National ProgramforFloodPlainManagement.Washington,DC.

PAGE 282

271UrbanDrainageandFlood ControlDistrict(Denver)1979"UDFCD--TheFirstTenYears," FloodHazardNews(December), pp. 1+. Waterstone,M.1978HazardMitigation Behavior ofUrbanFlood Plain Residents.WorkingPaper #35. Boulder: University of Colorado,Instituteof Behavioral Science. White,GilbertF.1975FloodHazardintheUnitedStates:A Research Assessment.Monograph#6. Boulder: University of Colorado,Instituteof Behavioral Science. Wright-McLaughlin Engineers1977"BigThompsonFloodDisaster:Final ReporttotheGovernor of Colorado." Denver,December.

PAGE 283

ThispageISblank

PAGE 284

PUBLICATIONSOFINTERESTfromtheNatural Hazards ResearchandApplications Information CenterInstituteof Behavioral Science#6CampusBox482University of Colorado Boulder, Colorado80309(303) 492-6818SPECIALPUBLICATIONS#2. Regulation of FloodHazardAreastoReduceFlood Losses,Volume3.JonKusler. 1982.300pp. $8.00 #3. FloodplainManagement,AppendixAtoVolume3 TSp A.Bloomgren. 1982.123pp. $8.00. #4. Innovation inLocalFloodplainManagement,AppendixBtoVolume3 TspiV2). JonKusler. 1982.262pp. $8.00 #5. Floodplain RegulationsandtheCourts 1970-1981.JonKusler. 1982.51pp. $5.00. #7. Preventing Coastal FloodDisasters:TheRole oftheStatesand Federar-Response. Proceedings of a NationalSymposium,May,1983. 1984.386pp. $10.00. #9. ImprovingtheEffectivenessof FloodplainManagementin WesternStateHigh-Risk Areas: Alluvial Fans, Mudflows,MudFloods. Proceedings of aWorkshop,February, 1984.1985.97pp. $7.00. #10. EvaluatingtheEffectivenessof FloodplainManagementTechniquesand communit\ Programs. Proceedings of a Seminar,April,1984.1985.143pp.8.00.#11.ManagingHighRisk Flood Areas:1985andBeyond.Proceedings oftheEighthAnnualConference of the Association ofStateFloodplain Managers, June, 1984. 1985.326pp. $8.00. #12. FloodHazardManagementinGovernmentandthePrivateSector. Proceedings oftheNinthAnnualConference of the Association ofStateFloodplain Managers,April,1985. 1986.358pp. $8.00. #15. StrengtheningLocalFloodProtectionPrograms. Proceedings oftheTenthAnnualConference of the Assoclation ofStateFloodplain Managers, June, 1986.1987.320pp. $10.00.

PAGE 285

WORKINGPAPERS#39.Effectsof a NaturalDisasteronLocal Mort9age Markets:ThePearl River Flood in Jackson,Mississippi--April,1979.D.AndersonandM.Weinrobe. 1980.48pp.$4.50.#47. DisseminatingDisaster-RelatedInformationtoPublicandPrivateUsers.ClaireB.Rubin. 1982.32pp.$4.50.#52.TheEffectsof Flood Hazard InformationDisclosurebyRealtors:TheCase oftheLowerFloridaKeys. John Cross. 1985.63pp.$4.50.#53. Local Reaction to}cquisition: AnAustralianStudy. JohnHandmer.f985.65pp. #54.TheEnvironmental Hazards of ColoradoSprings.EveGruntfest.1985. 5"Spp:$4:-50-;-------------------MONOGRAPHS#35.PerspectivesonIncreasingHazard Awareness.ThomasF.Saarinen,ed. .00:--------------#39. TerminalDisasters:ComputerApplicationsin Emergensr Management.SallieMarston, ed. 1ge6. 225pp. $10.00. #40. When theGroundFails:PlanningandEngineering ResponsetoDebris 11artha Blair.1985.110pp. $8.00. #41.CommunityRecoveryfroma MajorDisaster.ClaireRubinetal.1985. 2Spp:-$TD:"oo:-----------#45. RegionalManagementof MetropolitanFloodplains.RutherfordH.Platt,ed. 1987.347pp. $10.00.BIBLIOGRAPHIES#11. Natural HazardsandLandUsePlanning.AnnFitzSimmons. 1984.107pp. $5.50. ASelected,PartiallyAnnotated Bibliography of Recent (1984-1985) Natural HazardsPublications.David Morton. 1986.150 pp. $7.00.#12. A Bibliography of WeatherandClimate Hazards. William Riebsame,HenryDiaz,andToddMoses. 1986.410pp. $15.00.NEWSLETTER