Dam Sites Identification using Multi-Criteria Analysis and Spatial Weighted Overlay. The Case of Kapseret Sub-County, Kenya

Abstract

Water shortage is a common phenomenon in many parts of Kenya in the dry season, including the Kapseret Sub-County. However, water harvesting has seldom been practised, despite its high potential to alleviate water shortages in the dry season. This is largely influenced by a lack of access to dams and pans. The objective of this study was to identify potential dam sites for water harvesting in Kapseret Sub County, Uasin Gishu County, Kenya. Multiple criteria analysis and weighted overlay were performed on ArcGIS to map suitable sites for the location of dams. The multiple criteria considered in site suitability analysis were land use and land cover (LULC), slope, and proximity to streams, institutions, roads, and airports. Digital Elevation Model (DEM) of 30 m resolution was downloaded from the USGS website and used to process stream network, slope, and contours. Landsat 8 satellite imagery taken on January 2022 were downloaded from the USGS website and used to generate LULC data. It was established that the Kapseret basin has moderate to highly suitable zones for dam siting, covering 74.66% of the area with only 25.34% of the land being unsuitable. Further analysis using contours identified four potential dam sites with a combined capacity of 3,436,500 m3. The study concluded that the potential for water harvesting is high in the area as significant portions of the land are generally suitable for dam siting. It was recommended that action be taken by the county and other stakeholders to develop dams in suitable zones so as to increase access to water, particularly in the dry season when there are shortages.