Automated 12d Catchment Mapping with CatchmentSIM

Emergency Response Classificationsat Sub-Precinct Scales

David Tetley

1Presentation OutlineBackgroundStage 1 ERP Classifications (Lot Scale)Stage 2 ERP Classifications (Pixel Scale)Discussion2Why Complete Emergency Response Planning?Key component of FPRM process is managing the continuing flood risk.A key component of managing the continuing flood risk is ensuring Emergency Response Planning (ERP) is completed.Flood Emergency Response Planning Classification for Communities (2007) guideline prepared to assist in assigning ERP classifications to floodplain communities: ClassificationResponse RequiredResupplyRescue/MedivacEvacuationHigh Flood IslandYesPossiblyPossiblyLow Flood IslandNoYesYesArea with Rising Road AccessNoPossiblyYesArea with Overland Escape RouteNoPossiblyYesLow Trapped PerimeterNoYesYesHigh Trapped PerimeterYesPossiblyPossiblyIndirectly Affected AreaPossiblyPossiblyPossiblyTable 1: Response Required for Different ERP Classifications (DECC, 2007)3Current ERP Classification ApproachFrom: Flood Emergency Response Planning Classification for Communities (DECC, 2007)

4Limitations of Current ERP Classification ApproachWhat is a precinct?Broad scale classifications can make it difficult to prioritise emergency response requirements within precincts.Does not take full advantage of spatial datasets that are commonly produced as part of contemporary studies.Precinct approach focused on existing communities.5Stage 1 ERP Classification (Lot Scale)Computer program developed to automate ERP Classifications.Required Inputs:Digital Terrain Model (DTM)GIS file of sub-precincts (e.g., lots)GIS file of road networkHydraulic model water level output fileProbable Maximum Flood (PMF) extent polygonA range of default parameters6Stage 1 ERP Classification (Lot Scale)Computer program performs the following tasks:Analyses the road network and PMF extent to determine which roads serve as evacuation routes to points outside of floodplainDetermines when roadways become cut by floodwater preventing vehicular and pedestrian evacuationDetermines which precincts become isolated during the floodDetermines which precincts become flooded during the floodAssigns ERP Classifications to each precinct

7Stage 1 ERP Classification (Lot Scale)

8Stage 1 ERP Classification (Lot Scale)

1% AEP Depths (m)

LEGEND

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Stage 1 ERP Classification (Lot Scale)Vehicular evacuation route 0 hours after rainfall commences (1% AEP Flood)

1% AEP Depths (m)

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Stage 1 ERP Classification (Lot Scale)Vehicular evacuation route 2 hours after rainfall commences (1% AEP Flood)

1% AEP Depths (m)

LEGEND

11Stage 1 ERP Classification (Lot Scale)Vehicular evacuation route 8 hours after rainfall commences (1% AEP Flood)

1% AEP Depths (m)

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12Stage 1 ERP Classification (Lot Scale)Pedestrian evacuation route 9 hours after rainfall commences (1% AEP Flood)

1% AEP Depths (m)

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Stage 1 ERP Classification (Lot Scale)

1% AEP Depths (m)

LEGENDPedestrian evacuation route 18 hours after rainfall commences (1% AEP Flood)

14Stage 1 ERP Classification (Lot Scale)LEGEND

15Stage 1 ERP Classification (Lot Scale)

16Some limitations were identified in ERP Classification flow chart at small scalesAlternate ERP Classification was developed based on analysis of individual pixels (i.e., grid cells)Alternate approach considers same basic ERP factors but results are presented on a gradient of 13 classifications of increasing risk / emergency response requirementsStage 2 ERP Classification (Pixel Scale)17Definitions of Risk Gradient ERP ClassificationsCategoryDescriptionPMF ImpactsEvent Impact (e.g., 1% AEP Flood)Access CutSurroundedFloodedVehicular / Pedestrian Access CutSurroundedNo Rising Road AccessFloodedAny TimePrior to FloodingAny TimePrior to FloodingAny TimePrior to Flooding1Not flood affected2PMF IsolatedYES3PMF SurroundedYESYES4PMF liable, no expected impact (Rising road evacuation possible)YESYESYES5PMF liable, no expected impact (No rising road evacuation possible)YESYESYESYES6Isolated by vehicleYESYESYESYES7Surrounded by floodwatersYESYESYESYESYES8Flooded (Rising road evacuation possible)YESYESYESYESYESYES9Flooded (No rising road evacuation possible)YESYESYESYESYESYESYESYES10Flooded and isolated by vehicleYESYESYESYESYESYESYESYESYES11Surrounded by floodwaters and then flooded (Accessible high ground)YESYESYESYESYESYESYESYESYESYES12Surrounded by floodwaters and then flooded (No accessible high ground)YESYESYESYESYESYESYESYESYESYES13Permanently InundatedStage 2 ERP Classification (Pixel Scale)18Stage 2 ERP Classification (Pixel Scale)Time of First Inundation (1% AEP Flood)LEGEND

19Stage 2 ERP Classification (Pixel Scale)LEGEND

ERP Gradient (1% AEP Flood Existing Conditions)

20Stage 2 ERP Classification (Pixel Scale)LEGEND

ERP Gradient (1% AEP Flood Existing Conditions)21Stage 2 ERP Classification (Pixel Scale)LEGEND

ERP Gradient (1% AEP Flood with Upgraded Roadway )

22DisadvantagesSignificant amount of pre-processing may be requiredSignificant computational time (60km2, ~30000 lots & 2m pixel size = 12 hours)Information overload? 23Future WorkIncluding additional criteria to determine when evacuation routes become cutCustomised assessment of vulnerable community assets (e.g., hospitals, retirement villages, schools)Potential for different pedestrian/overland escape routes relative to vehicular escape routesOptimising software for improved run-times24ConclusionLimitations identified with ERP classification workflow when applied at small scalesAutomated ERP classification is possible at small scales and offers a range of useful information to assist with emergency response management.ERP gradient approach has potential to offer improved spatial definition of emergency response requirementsFurther improvements to computer program planned 25Questions?

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