The U.S. Multi-Hazards (Hazus-MH) Flood Model allows planners and other practitioners to carry out a wide range of flood hazard analyses, including:
- Studies of specific return intervals of floods (e.g., 100-year return interval).
- Studies of discharge frequencies, including analysis of discharges from specific streams and the exposure to buildings and population from the resultant flooding.
- Studies of annualized losses from flooding.
- Quick Look assessments, which allows the user to quickly evaluate potential flooding from specific flood depths at specific locations.
- What if scenarios, which allow users to evaluate the consequences of specific actions, such as the introduction of flow regulation devices, acquisition of flood-prone properties, and other mitigation measures.
The flood loss estimation methodology consists of two modules that carry out basic analytical processes: flood hazard analysis and flood loss estimation analysis. The flood hazard analysis module uses characteristics, such as frequency, discharge, and ground elevation to estimate flood depth, flood elevation, and flow velocity. The flood loss estimation module calculates physical damage and economic loss from the results of the hazard analysis.
New Features in Hazus-MH 2.1 Flood Model
- Menu options in the user interface of the three models in Hazus-MH (Earthquake, Flood & Hurricane) have been adjusted to provide greater consistency.
- In recognition of the uncertainties inherent in hurricane forecasts, the Coastal Surge analysis capability has been disabled for forecast/advisories issued more than 24 hours before the expected time of landfall.
- The Flood Model Average Annualized Loss (AAL) analysis has been reactivated with the following changes:
- The 2 and 5 year return period extrapolations have been removed from the methodology.
- The 200-year return period has been replaced by a 25-year return period in the methodology.
Refer to the Hazus–MH 2.1 Flood Technical Manual for complete details on the Flood AAL methodology.
- A riverine level 1 study region automation feature has been added to the Flood Model.
- The Flood Model is now processing Manning’s roughness coefficients dynamically based on a LULC grid as part of the Develop Stream Network process.
- The Flood Model Hydraulics process has been optimized for scenarios where a suite of return periods is being analyzed.
Hazus-MH Flood Model Applications
The Flood Model has been widely used by state and local officials for risk assessment and mitigation planning, including:
- Savannah, Georgia Flood Loss Estimates and CRS Flood Mitigation Planning (2009)
- Using Hazus to Speed Disaster Recovery From 2008 Iowa Floods (2009)
- Pennsylvania Statewide Flood Hazard Study (2007), which includes damage estimates for 10-, 50-, 100-, 200- and 500-year flood events.
- State of Maryland Flood Hazard Study (2006), which includes a vulnerability assessment of the state's built environment to riverine and coastal flooding.
- Use of Hazus-MH in the Risk Assessment of 29 Counties in Indiana (2006)