Untitled-2.png Back Home Again in Indiana INTEGRATING DFIRM FLOOD DEPTH GRIDS WITH HAZUS-MH TO ESTIMATE LOSS AND COMMUNICATE RISK Risk MAP Eric Coughlin, GISP, CFM Sr. GIS Analyst PBSJ Presentation Outline •The Risk MAP era begins… •Pilot study using DFIRM depth grid in a “Level 1.5” HAZUS analysis to estimate loss •Compare loss estimates between HAZUS- generated H&H and DFIRM depth grid •Techniques and tools for communicating risk to a wide audience to aid in reducing loss of life and property What is Risk MAP? •Mapping, Assessment, Planning •VISION:Deliver quality data that increases public awareness and leads to actions that reduces loss of life and property •An integrated approach to identifying flood hazards and merging flood risk assessments into hazard mitigation plans (Information Redistribution) Risk MAP Goals 1.Address gaps in flood hazard data for actuarial soundness of the NFIP 2.Increase flood-risk awareness that results in a reduction of vulnerability to flooding 3.Engage in risk-based mitigation planning to reduce loss of life and property 4.Provide a digital platform that improves resource management and data sharing 5.Develop synergies to enhance decision-making through effective risk communication Risk MAP Lifecycle Risk-MAP-graphic-250.png Graphic courtesy of FEMA Map Mod ..Risk MAP Map Mod Maps hazusFl.png Risk MAP Tools Bulloch County Flood Risk Study Bulloch County Flood Risk Study STUDY GOALS 1.Identifyflood risk to communities 2.Communicateflood risk to stakeholders 3.Realizea Map Mod ..Risk MAP project (take DFIRM data into the real world) Bulloch County Flood Risk Study ga.jpg DFIRM Engineering Parameters •FEMA’s Guidelines and Specifications for Flood Hazard Mapping Partners •Hydrology –Boundaries interpolated between surveyed cross sections at scale of 1:400 with a 2- foot contour interval •Hydraulics –100-year return period Flood Depth Grids Water Surface - Ground Surface = Flood Depth hazusFl.png Using DFIRM in HAZUS •Processed DFIRM data (cross sections with WSEL + SFHA boundary) in ArcMap 3D Analyst to create depth raster •All HAZUS needs is this depth raster •Not necessary to run hydrology in HAZUS •Hydraulics step to process depth grid took 1 minute 26 seconds HAZUS Flood Model •Hydrology –10-meter NED DEM –2 sq. mile drainage area •Hydraulics –100-year return period •Total Time –32 hours (‘create study region’ through ‘run analysis’) UD Depth Grids in HAZUS 1.‘User Data’; set parameters 2.Create Scenario 3.Run Hydraulics 4.Run Analysis 5.Extract Results Utilizing a UD Depth Grid •When data is available •When project calls for enhanced data •Compare HAZUS H&H with engineering data from other methods in a ‘Level 1.5’ analysis (no local building or damage function used) •Align with Risk MAP goals HAZUS Flood Risk Assessment •What results did we want to extract from HAZUS to identify and communicate risk for a 1-percent annual chance flood using recently developed DFIRM data? –Direct physical damages to GBS –Direct economic losses by occupancy type –Agricultural crop losses –Social vulnerability Results: Total Flooded Area •Bulloch County is 682 sq. miles •DFIRM: 104 sq. miles flooded –15% of county •HAZUS: 117 sq. miles flooded –17% of county COUNTY MAP WITH FLOOD ZONE DELINEATIONS Results: GBS Damages DAMAGED BUILDING COUNTS BY OCCUPANCY TYPE (DFIRM) Occupancy Type Total in County Number of Buildings in Each Damage Percentage Range Total Damaged Per Type 1 to 10% 11 to20% 21 to 30% 31 to 40% 41 to 50% 51 to 100% (Substantial Damage) Residential (Pre-FIRM) 20,752 0 6 56 9 27 90 188 Residential (Post-FIRM) 0 3 25 2 11 53 94 Commercial 1,402 0 2 0 0 0 0 2 Industrial 402 0 0 0 0 0 0 0 Agricultural 179 0 0 0 0 0 0 0 TOTAL BUILDINGS 22,735 0 11 81 11 38 143 284 DAMAGED BUILDING COUNTS BY OCCUPANCY TYPE (HAZUS) Occupancy Type Total in County Number of Buildings in Each Damage Percentage Range Total Damaged Per Type 1 to 10% 11 to 20% 21 to 30% 31 to 40% 41 to 50% 51 to 100% (Substantial Damage) Residential (Pre-FIRM) 20,752 0 8 61 1 1 37 108 Residential (Post-FIRM) 0 5 30 0 1 15 51 Commercial 1,402 0 2 0 0 0 0 2 Industrial 402 0 0 0 0 0 0 0 Agricultural 179 0 0 0 0 0 0 0 TOTAL BUILDINGS 22,735 0 15 91 1 2 52 161 Results: Direct Economic Losses TABLE 5. DIRECT ECONOMIC IMPACTS (DFIRM) Occupancy Type Building Damage Residential $27,720,000 Commercial $2,550,000 Industrial $1,560,000 Agricultural/Other $530,000 TOTAL FOR ALL OCCUPANCY TYPES $32,360,000 TABLE 5. DIRECT ECONOMIC IMPACTS (HAZUS) Occupancy Type Building Damage Residential $16,454,000 Commercial $2,471,000 Industrial $1,164,000 Agricultural/Other $136,000 TOTAL FOR ALL OCCUPANCY TYPES $20,225,000 Results: EF Damages EXPECTED DAMAGE TO ESSENTIAL FACILITIES (DFIRM & HAZUS) Type of Facility Total Number Number of Facilities in Each Damage Classification At Least Moderate At Least Substantial Loss of Use (In Number of Days) EOC 0 0 0 0 Fire Station 4 0 0 0 Medical Care Facility 2 0 0 0 Police Station 9 0 0 0 School 21 0 0 0 TOTAL FACILITIES 36 0 0 0 Results: Agricultural Losses DIRECT ECONOMIC LOSS FOR AGRICULTURE PRODUCTS (DFIRM) Type of Crop Cumulative Dollar Value of Losses Based on Flood Duration Crop Loss with < 1 Day of Inundation Crop Loss with 3 Days of Inundation Crop Loss with 7 Days of Inundation Crop Loss with 14 Days of Inundation Corn $0 $509,000 $678,000 $678,000 Soybeans $0 $20,000 $27,000 $27,000 TOTAL FOR ALL CROP TYPES $0 $529,000 $705,000 $705,000 DIRECT ECONOMIC LOSS FOR AGRICULTURE PRODUCTS (HAZUS) Type of Crop Cumulative Dollar Value of Losses Based on Flood Duration Crop Loss with < 1 Day of Inundation Crop Loss with 3 Days of Inundation Crop Loss with 7 Days of Inundation Crop Loss with 14 Days of Inundation Corn $0 $293,000 $391,000 $391,000 Soybeans $0 $12,000 $15,000 $15,000 TOTAL FOR ALL CROP TYPES $0 $305,000 $406,000 $406,000 Results: Social Vulnerability ESTIMATED SOCIAL IMPACTS (DFIRM) County Pop. Number of Households or Persons in Each Category Households Displaced Individual Persons Displaced Individual Persons Seeking Shelter 55,983 1,379 4,138 (7%) 2,020 (4%) bulloch_pop_displaced_01 DISPLACED POPULATION ESTIMATED SOCIAL IMPACTS (HAZUS) County Pop. Number of Households or Persons in Each Category Households Displaced Individual Persons Displaced Individual Persons Seeking Shelter 55,983 1,110 3,330 (6%) 1,623 (3%) *Displaced households assumes the Georgia average of 3 persons per household Study Conclusions •Mitigation Opportunities –143 substantially damaged residential buildings ..Acquire and demolish ..Elevate ..Relocate ..Flood-proof or retrofit •Agricultural Considerations –Crops are vulnerable; further study needed •Social Vulnerability Concerns –7% of pop. displaced –Further study needed to determine geography of at-risk population –Sheltering plans should be developed Traditional Risk Communication •Prepared reports •Community officials •Public meetings •News media Risk Communication •Natural hazards are stressful •Facilitate dialog and prioritize hazard knowledge •Science + policy + common sense •Reach all populations •We have our work cut out for us… Risk Communication •An awarepublic is an empoweredpublic •georgiadfirm.com Web_Map_Viewer_Risk_Profile_w_HAZUS[1].jpg Lessons Learned •Appreciated the flexibility of UD depth grids •Use CDMS, use CDMS, use CDMS –Update population data –Update essential facilities –Use local assessor’s data where available •Study additional results: vehicles, debris, indirect economic losses, etc. •Recognized that effective communication is the key Questions? Thanks! Eric Coughlin, GISP, CFM Sr. GIS Analyst PBSJ Raleigh, NC 919-876-6888 eccoughlin@pbsj.com