Mapping of Flood Risk Zones in Ala River Basin Akure, Nigeria

Abstract

Floods are water induced disasters that lead to temporary inundation of dry land and cause serious damages in the affected location such as loss of lives and properties and destruction of infrastructures. Nigeria has experienced a lot of flood incidences and the impact of flood has also increased due to population growth coupled with uncontrolled developmental practices. The result of this is pressure and congestion in urban land areas. This in turn forces a considerable number of people to settle in unsafe areas with inherent risk to flood which is the case in Ala river basin, Akure, Ondo state. The aim of this research study to make an assessment of flood risk vulnerability in Ala river basin area. Multicriteria Evaluation methods were used to analyse flood vulnerable areas. The causative factors of flood within the basin taken into consideration includes slope, distance to drainage, drainage density, soil type and land use. Geographical information system was integrated with Fuzzy Logic to classify the various causative criteria. Fuzzy overlay was used to generate the flood risk map in Ala river basin identifying low, medium and high flood risk zones which would be made available to policy and decision makers as a decision support system in tackling flood.