Methods for flood risk and vulnerability mapping: experiences from the Ratu watershed, Nepal

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The method used to assess the flood risk and vulnerability mapping consisted in:

  • Assessing vulnerability-Tools and methods
  • Field Survey and group discussions
  • Mapping for Preparedness
    The mapping was done adopting three different approaches:

-          A geomorphic approach to hazard mapping using geographical information systems (GIS) and remote sensing (RS)

-          Hazard mapping through the measurement of rainfall-runoff processes using US Army Corps of Engineers Hydrological Engineering Corporation’s River System Analysis (HEC-RAS) model

-          Social flood hazard mapping based on local people’s perceptions and experiences

The main sources of information were:

Maps, aerial photographs, satellite images, household survey, group discussions, field observation and published and unpublished documents.

GIS based software such as ArcView, ILWIS, and HEC-GeoRas were used for data processing and analysis.


IFM approach for flood mitigation in watershed scale

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A method for all stakeholders to participate in decision making. The purpose of IFM is optimum use of flood opportunities with minimum flood damages to society and environment. It is a new approach whereby all aspects of flood issues – including: technical, social, economical, environmental, Institutional and legal aspects – are considered in flood management decisions. Case study: Kan Basin” was studies for a watershed in Tehran province, Iran. Selected strategies are given to  stakeholders for them to select the final combined strategy to be implemented in the watershed. In the second category, duties of the agencies and institutions are as assigned through the prepared Incident ‍Command System (ICS) and Emergeny Action Plan (EAP) for reduction of the remained flood risk in time of the crisis.