Flood Hazard Zonation using Spatial Multi-Criteria Evaluation (SMCE) in GIS (Case Study: Omidieh - Khuzestan)

Abstract

This study aims to discover the risk reasons, effective in flooding and the flood-susceptible areas. The researcher uses GIS and SMCE to identify the watershed of Omidieh and Bidboland 1262.25 Km2 area. So, the researcher first examines the causes affecting flooding. These reasons included: slope, land use, geology, erosion rates, soil texture, average annual rainfall, drainage density and vegetation of the area. Then, after describing data collection, Boolean and Fuzzy rules standardized the reasons in the SMCE model. Analytic hierarchy process (AHP) determined the weight of each case. The next step was to integrate GIS layers by designing a criteria tree which resulted in the composite index map with fuzzy values (from 0 to 1). As a result, areas with values closer to one, equal to 466.025 Km2, were flooding-susceptible areas. The results show that about 62% of zonation area runs zero-​risk while the remaining areas have a higher potential of flooding in a Northeastern – Southeastern strip. This higher risk is because of less time focus, higher slope, and lower permeability of surface ground. Low vegetation, closeness to oil and gas installations and residential areas are other reasons. The potential for more flooding included 13% low risk, 23% moderate risk and 2% high-risk. To control and reduce the risk of flood damage, officials should take special measures.