HAZUS ®MH Coastal Flood Hazard Analysis FATIH C. DOGAN ABS CONSULTING

ABS Consulting HAZUS ®MH Overview Standardized, nationally applicable natural hazards loss estimation methodology Developed by FEMA, under a cooperative agreement with NIBS ( & GIS (Geographic Information System) based HAZUS-99 SR2 currently has MapInfo ® and ArcView ® versions

ABS Consulting HAZUS ®MH Components Next generation HAZUS currently under development Expanded with multi-hazard methodology for estimating potential losses from wind and flood hazards.  Flood Model (riverine and coastal flooding)  Wind Preview Model (hurricane direct damage only)

ABS Consulting HAZUS ®MH Single user GIS-based software package Designed for ArcGIS version with the Spatial Analyst extension Windows 2000 operating system Scheduled for release first quarter 2003

ABS Consulting HAZUS ®MH Flood Model Results Available formats: maps, tabular, summary reports Hazard maps – flood depth, erosion depth Building stock loss – structure and contents Lifeline damage – bridges, treatment plants Shelter requirements Indirect economic losses – market sector recovery Produced for specific return periods, suites of return periods, or annualized losses Can be exported for use with enterprise GIS

ABS Consulting 1. Define Hazard: (Flood Surface- Land Surface) 2. Define and Overlay Inventory 4. Estimate Losses 3. Determine Damage HAZUS ®MH Flood Model Methodology

Subtract ground surface from flood surface to determine flood depth throughout the study area Datum Ground Elevation Flood Elevation HAZUS ®MH Flood Model Hazard Determination

ABS Consulting Pre-storm ground surface from DEM HAZUS ®MH Flood Model Coastal Hazard Adjust ground surface to account for dune erosion Calculate flood surface grid through wave height and runup analyses Map A and V coastal flood hazard zones Calculate flood depth grid as flood surface - ground surface

ABS Consulting HAZUS ®MH Flood Model User Input Study region created through HAZUS shell DEM Return period to analyze Select shoreline(s) Segment and characterize shoreline(s) Shoreline type 100 yr SWEL and wave setup (from an FIS or other source)

ABS Consulting HAZUS ®MH Flood Model Segments & Transects Segment based on common characteristics Transects every 1000ft or so Tr 1-1 Tr 1-2 Tr 1-3 Tr 1-4 Tr 1-5 Tr 1-0 Segment 1 Segment 2 Tr 2-1 Tr 2-2 Tr 2-0 Tr 2-3

ABS Consulting Transect Profiles Query DEM along the transect with an interval of cellsize/ 3

ABS Consulting FEMA Guidelines Mean Sea Level Dune reservoir Stillwater Elevation Dune Toe Dune Peak Ridge Type Mean Sea Level Dune Peak Dune reservoir Stillwater Elevation Dune Toe Mound Type (Rear Shoulder)

ABS Consulting FEMA Guidelines (cont.) Adjustment of profile to approximate post storm eroded profile: Dune Removal Dune Retreat For a 100-year storm, the frontal dune reservoir should be at least 540sqft (or 20 cubic yards volume per along the shore) to prevent REMOVAL.

ABS Consulting HAZUS ®MH Flood Model Estimating Dune Peak and Toe Dune Peak: The highest point along the transect profile within the first 500ft landward of shoreline. Dune Toe: The most landward intersection of 10 year SWEL with the transect profile. (must be seaward of peak)

ABS Consulting HAZUS ®MH Flood Model Estimating Frontal Dune Reservoir N-year SWEL: Calculated based on default ratios (Ex: Atlantic 10yr 64%, 50yr 88%, 500yr 123%) Required reservoir to prevent removal: Based on return period and coastal area (Lake Ontario, other Great Lakes, all other areas) Res.= 0.7A+B Mean Sea Level 10 yr SWEL N-yr SWEL Dune Toe Dune Peak A B

ABS Consulting FEMA Removal & Retreat Dune reservoir Adjusted Ground Profiles Original Ground Profile Stillwater Elevation Dune Toe Dune Peak Retreat Removal

ABS Consulting HAZUS ®MH Flood Model Coastal Erosion Mean Sea Level 10 yr SWEL N-yr SWEL Dune Toe Dune Peak 1 on 50 No adj. Horizontal1 on 50 slope REMOVAL Dune Toe 1 on 50 Usually removed volume is enough to fill lower areas

ABS Consulting HAZUS ®MH Flood Model Coastal Erosion Mean Sea Level 10 yr SWEL N-yr SWEL Dune Peak 1 on 40 No adj. Horizontal at toe elev. 1 on 40 slope RETREAT Check removed volume against the required reservoir, iterate until close enough. 1 on 1

ABS Consulting Create points with z-value from the eroded transect profile Interpolate new surface grid which will be used in WHAFIS and Runup calculations to create flood surface grid. Flood surface- Eroded ground= Flood depth Subtract eroded ground grid from original ground to get “Erosion Depth Grid” HAZUS ®MH Coastal Erosion

ABS Consulting Long-term erosion – inventory location Shore protection – erosion susceptibility Buyout – inventory location Building codes – first floor elevation/ elevated structures HAZUS ®MH Coastal What-If Scenarios