11/20/2006

UTRCA UTRCA Flood Damage AssessmentFlood Damage Assessment

Matt Wood Matt Wood –– Water Resources TechnicianWater Resources Technician

Rick Rick GoldtGoldt -- HydrologistHydrologist

OutlineOutlineHydraulic ModelingHydraulic Modeling

FloodlineFloodline MappingMapping

Flood Damage Model SelectionFlood Damage Model Selection

Depth Damage FunctionsDepth Damage Functions

Structure DatabaseStructure Database

Stream Reach and Index Cross SectionStream Reach and Index Cross Section

Elevation EstimatesElevation Estimates

ConsiderationsConsiderations

Hydraulic ModelingHydraulic ModelingReview of existing models:Review of existing models:

Geometry Check (from HECGeometry Check (from HEC--2 Import)2 Import)BridgesBridgesCross SectionsCross Sections

Flow CheckFlow CheckIncluded boundary conditionsIncluded boundary conditions

Output CheckOutput CheckConsistency between HECConsistency between HEC--RAS and HECRAS and HEC--2 Outputs2 Outputs

Interpolation of FlowsInterpolation of FlowsNot all of the required flows were assessed in original Not all of the required flows were assessed in original modelingmodelingHECHEC--FDA requires FlowFDA requires Flow--Stage data for 2, 5, 10, 25, Stage data for 2, 5, 10, 25, 50, 100, 250 and 500 year return periods 50, 100, 250 and 500 year return periods Missing flow values (and B.C.) were calculated using a Missing flow values (and B.C.) were calculated using a logarithmic interpolation/extrapolationlogarithmic interpolation/extrapolation

HECHEC--RAS cross sections for the watershed were RAS cross sections for the watershed were digitized into GIS from hardcopy mappingdigitized into GIS from hardcopy mapping

Database of HECDatabase of HEC--RAS outputs was createdRAS outputs was created

Flow and water surface elevationsFlow and water surface elevations

2, 5, 10, 25, 50, 100, 250, 500 year returns2, 5, 10, 25, 50, 100, 250, 500 year returns

Used interpolated flows were necessaryUsed interpolated flows were necessary

Output database was joined with digitized cross Output database was joined with digitized cross sections in sections in ArcMapArcMap and exported to a and exported to a GeodatabaseGeodatabase

FloodlineFloodline MappingMapping

Flood Damage Model SelectionFlood Damage Model Selection

Two models available:Two models available:

FLDAM v2.1FLDAM v2.1

HECHEC--FDA 1.2FDA 1.2

FLDAM v2.1FLDAM v2.1

Developed by MNRDeveloped by MNR

DOS BasedDOS Based

DepthDepth--$Damage/Unit Area curves built into program$Damage/Unit Area curves built into program““Flood Damage Estimation GuideFlood Damage Estimation Guide”” Ministry of Natural Ministry of Natural Resources 1990Resources 1990

Information on newer versions is unavailableInformation on newer versions is unavailable

Support/Documentation is not readily availableSupport/Documentation is not readily available

Flood Damage Model SelectionFlood Damage Model Selection

HECHEC--FDA v.1.2FDA v.1.2Developed by HECDeveloped by HECWindows BasedWindows BasedCompatible with HECCompatible with HEC--RAS outputRAS outputContains FEMA style risk based analysis procedures Contains FEMA style risk based analysis procedures for evaluating past and future damage reduction for evaluating past and future damage reduction measuresmeasuresGIS compatible version 2.0 is in the works pending GIS compatible version 2.0 is in the works pending fundingfundingSoftware is available free of chargeSoftware is available free of charge

HECHEC--FDA was selected for use in the flood FDA was selected for use in the flood damage studydamage study

Residential DepthResidential Depth--DamageDamageOntario, CanadaOntario, Canada

Paragon Engineering Limited, Ontario Ministry of Paragon Engineering Limited, Ontario Ministry of Natural Resources, "Development of Flood DepthNatural Resources, "Development of Flood Depth--Damage Curves for residential Homes in OntarioDamage Curves for residential Homes in Ontario--VolVolI I -- Technical Report" 1985Technical Report" 1985

Uses Depth vs. Direct Structural $ Damage/Footprint AreaUses Depth vs. Direct Structural $ Damage/Footprint AreaAvailable for :Available for :

One story with and without basementOne story with and without basementTwo story with and without basementTwo story with and without basementSplit levelsSplit levelsTownhousesTownhousesMobile HomesMobile Homes

Not directly compatible with HECNot directly compatible with HEC--FDAFDAUpdate to curves recommended by PEIL for MNR in 2004Update to curves recommended by PEIL for MNR in 2004Attempting to get curves updated to DepthAttempting to get curves updated to Depth--Percent DamagePercent Damage

USACE, USAUSACE, USA

Curves Curves publisedpublised in Economic Guidance in Economic Guidance Memorandum (EGM) 04Memorandum (EGM) 04--01 Generic Depth01 Generic Depth--Damage Damage relationships, USACE 2003relationships, USACE 2003

Use Depth vs. Percent Damage Use Depth vs. Percent Damage Same as HECSame as HEC--FDAFDA

Available for:Available for:One StoryOne Story

Two StoryTwo Story

Split LevelSplit Level

*with Basement (2003) without Basement (2000)*with Basement (2003) without Basement (2000)

Include standard deviation of errorInclude standard deviation of error

Residential DepthResidential Depth--DamageDamage

Commercial DepthCommercial Depth--DamageDamage

Alberta, CanadaAlberta, Canada

IBI Group, "Fort McMurray Flood Damage Reduction IBI Group, "Fort McMurray Flood Damage Reduction Program", Phase IIProgram", Phase II--B, Final Report to B, Final Report to AthabascaAthabascaRiver Basin, Alberta Environment, Edmonton River Basin, Alberta Environment, Edmonton Alberta, 1982Alberta, 1982

Uses Depth vs. Direct Damage/Footprint AreaUses Depth vs. Direct Damage/Footprint Area

Available for:Available for:18 different commercial types18 different commercial types

Curves not entirely compatible with HECCurves not entirely compatible with HEC--FDAFDA

Industrial/Utilities Industrial/Utilities DepthDepth--DamageDamage

Structure specific DepthStructure specific Depth--Damage Relationship Damage Relationship will be developed when warranted.will be developed when warranted.

Ex// Ex// -- Pollution Control PlantsPollution Control Plants

-- RoadwaysRoadways

-- Large Industrial ComplexesLarge Industrial Complexes

Survey/Existing PlansSurvey/Existing Plans

Only used if Commercial curves do not Only used if Commercial curves do not adequately represent the structure/valueadequately represent the structure/value

Not considered at this timeNot considered at this time

May have significant impact on estimate as many May have significant impact on estimate as many of the floodplains in the area are used for of the floodplains in the area are used for agricultureagriculture

No research has been done in Ontario No research has been done in Ontario (MNR 1990)(MNR 1990)

AGRICORP AGRICORP only records damage that has occurredonly records damage that has occurred

OMAFRA OMAFRA ??

Challenge:Challenge:

Highly Dependant on:Highly Dependant on:Time of yearTime of year

Areal extent of floodingAreal extent of flooding

Duration of inundationDuration of inundation

Agricultural DepthAgricultural Depth--DamageDamage

Difficult to quantify in large scale study

Structure DatabaseStructure DatabaseCurrently being developedCurrently being developedIncludes all structures that fall within the 1:500 Includes all structures that fall within the 1:500 year flood extentsyear flood extentsContains information on:Contains information on:

Type (Type (ieie. Residential, Commercial, Industrial, etc. Residential, Commercial, Industrial, etc……))Street name and numberStreet name and numberDamage Category (Curve Used) Damage Category (Curve Used) Structure Classification <Structure Classification <-- not required by HECnot required by HEC--FDAFDAElevation of both grade, 1Elevation of both grade, 1stst floor and lowest openingfloor and lowest openingX, Y coX, Y co--ordinates of grade elevation locationordinates of grade elevation locationFootprint area (from GIS)Footprint area (from GIS)Possibly a Digital PhotoPossibly a Digital PhotoMay require structure value May require structure value for USACE Curvesfor USACE Curves

Stream Reach and Stream Reach and Index Cross SectionIndex Cross Section

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Damage ElevationsDamage ElevationsGIS GIS BasedBased Method:Method:

Why? Why? Over 4000 susceptible structuresOver 4000 susceptible structuresWhat? What? Will obtain an estimate of the lowest grade elevation for Will obtain an estimate of the lowest grade elevation for everyevery structure.structure.How? How?

-- Structures within 500yr are identified using aerial photographyStructures within 500yr are identified using aerial photographyand topographic mappingand topographic mapping-- Building footprints of identified structures are then obtainedBuilding footprints of identified structures are then obtained-- Lowest elevation at grade around footprint is determined based Lowest elevation at grade around footprint is determined based on on most accurate DEM for the areamost accurate DEM for the area

Windshield survey confirms grade elev. and estimates elev. Windshield survey confirms grade elev. and estimates elev. of first floor, lowest opening + other relevant infoof first floor, lowest opening + other relevant infoDetailed survey done on valuable structures (ex// Detailed survey done on valuable structures (ex// industrial/utility sites)industrial/utility sites)Where available: Existing Survey Data Overrides Estimated Where available: Existing Survey Data Overrides Estimated ElevationsElevations

ConsiderationsConsiderations

Most likely a number of HECMost likely a number of HEC--FDA filesFDA files

Ex// Stratford, London, Ex// Stratford, London, IngersollIngersoll

Only existing conditions will be modeledOnly existing conditions will be modeled

Data assemblage has been designed in hopes that Data assemblage has been designed in hopes that it will be compatible with future damage it will be compatible with future damage estimate software.estimate software.

All HECAll HEC--RAS files will be stored and untouched RAS files will be stored and untouched to ensure control in assessing effects of climate to ensure control in assessing effects of climate change.change.

ConsiderationsConsiderationsDecision on which structural damage curves to Decision on which structural damage curves to use for all structures.use for all structures.

Develop a plan for evaluating value of structure Develop a plan for evaluating value of structure (if USACE curves are chosen)(if USACE curves are chosen)

Need guidance on:Need guidance on:

ContentsContents

Intangible losses (including social)Intangible losses (including social)

Other losses (ex// Agricultural, landscaping, Other losses (ex// Agricultural, landscaping, Infrastructure)Infrastructure)

Questions?Questions?