Application of Particle Swarm Optimization based Fuzzy AHP for Evaluating and Selecting Suitable Flood Management Reservoir Locations in Adamawa Catchment, Nigeria

Seasonal flooding arising from current climate changes is a major problem in Adamawa catchment. Flood management reservoirs is a useful tool to catch flood, prevent jump, reduce congestion of runoff in the plains, and implement a long-time solution to the existing flood threats. This study applies Particle Swarm Optimization (PSO) based Fuzzy AHP to model flood reservoir site selection in Adamawa catchment located in the Upper Benue River Basin of Nigeria. Nine essential criteria and constraint were identified based on literature, and evaluation by experts. Weighted Linear Combination algorithm was modified and used to aggregate information from the factors and constraint. Pairwise Comparison Matrix (PCM) was obtained and weights for each of the PCM were determined using a Fuzzy Analytical Hierarchical Process (AHP) based PSO algorithm. MATLAB software was used to implement the PSO algorithim to derive the weights in the PCM. Consistency of generated weights obtained is not above 0.00213. The method resulted to a reservoir sites suitability map. Analysis of the proposed best reservoirs shows that, the maximum height of reservoirs corresponding to cross section of reservoir locations varies from 3m to 11m; width of reservoir varies from 140m to 680m; the maximum storage capacity varies from 66,768 m3 to 4,242,975m3; maximum surface area of the reservoir varies from 11,602m2 to 955,871m2. Field verification was conducted and most of the identified sites correspond with field based studies. Potential impacts of the candidate sites were identified and baseline survey data obtained in the field were engaged to establish the present state of the environment, taking into account changes resulting from natural events and from other human activities before arriving at top ranking sites. This present study has provided solution to the flood problem in Adamawa catchment through selection of suitable location for siting flood mitigation reservoirs.