Determination of Rivers` Flood Plain Risk`s Level by Multi Criteria Decision Making

Document Type : Research Article

Authors

Abstract

Flood plain is the preferred place for agricultural and other socio-economic activities. High density
flood plain’s residential region shows this fact. These advantages encourage societies to invade river’s
bed and right-of-way. Lots of changes occur due to this invasion and cause some morphological and
ecological damages. On the other hand, rivers are subject to floods. Therefore, determination of risk of
river’s bed and right-of-way directly relate to flooding damages and flood management plans.
In this paper, a new method for hazard and risk determination of river bed and right-of-way is
proposed. The approach is Integrated Flood Management (IFM). IFM not only concerns to river
hydraulics and technical issues, but it considers other issues like legal, environment and socioeconomic
conditions. This study tries to create a new method for determination of flood risk in the
floodplain. We have composed ordinary flood zone mapping (technically using numeric hydraulic
models) for Fordo River in Qom province in IRAN. We have also used a Multi Criteria Decision
Making (MCDM) approach, which represents IFM aspects to produce another set of flood zoning map
by IFM approach. In this procedure, we have benefited from an Analytically Hierarchy Process (AHP)
to define land use flood risks. Final map was produced by merging technical map and IFM map.
To sum up, new proposed method shows moderate and reasonable zoning instead of hydraulic flood
hazard and risk mapping because it uses more criteria for determining the level of flood`s risk in
floodplain. Furthermore, this method is more reliable for flood insurance and early flood warning
systems or flood damage mitigation, particularly in metropolitan areas.