Potential dam sites selection using integrated techniques of remote sensing and GIS in Imo State, Southeastern, Nigeria

Abstract

Water is an essential natural resource that is vital for sustaining every form of life existence. Availability of groundwater is spatially and temporally dependent upon the terrain of an area. In order to improve efficiency and effectiveness in water availability, supply and use, the construction of water harvesting structures across streams/watersheds is gaining drive in recent years. The increase in demand for water has led to the construction of water storage dams for various purposes such as community and industrial use, irrigation, flood control, hydropower and river canalization. Safety is the key consideration than cost and capacity as the failure of a dam often results to severe loss of lives and properties, hence the need to consider some important criteria for suitable dam siting. In this study, potential sites for construction of dams in Imo State, Nigeria, have been identified by using geographical information system and remote sensing techniques which were integrated with fuzzy logic to achieve the study objectives. Climatic and geophysical factors such as rainfall, runoff, stream order, soil type, geology type and land use were considered. These factors assigned fuzzy membership classes according to their contribution in locating suitable dam sites. The fuzzy members for all the factors were combined using the fuzzy overlay technique to produce the suitable dam site selection map. Majority of the selected sites were located in the northwestern part of Imo State which is characterized by high elevation and gentle slope.