In Detail: Flood Hazard Assessment

Recommended Practice: Flood Hazard Assessment
Step-by-Step: Flood Hazard Assessment

The objective of this practice is to carry out flood hazard assessment, identify the potential flood prone areas and potentially affected infrastructure namely roads, settlements, agriculture and in-land areas etc. against flood hazard of particular return period i.e. 2, 5, 10, 25, 50 and 100 years.

This Recommended Practices uses the HEC-RAS 2D flood model. The model was developed by US Army Corp of Engineer’s Hydrological Engineering Center (HEC). The model can solve 1D and 2D flood hazard problems through 1D, 2D and 1D/2D coupling approaches.

HEC-RAS 2D requires following geometric datasets:

  • Digital Elevation Model (DEM)
  • Landcover/Landuse Map
  • Manning’s n layer
  • 2D Flow Area
  • Boundary condition lines
  • River Cross-sections (in case of 1D and 1D/2D coupling approach)
  • Embankments
  • Restricted areas (if any)  

The insights obtained through this Recommended Practice can be used by disaster management agencies and other stakeholders to plan flood rescue, relief and mitigation activities.