Multi-Criteria Analysis for Effective Rain Water Harvesting Site Identification in Konso Zone, Ethiopia

Abstract

The Konso area of southern Ethiopia has limited resources and is highly vulnerable to climate change. Traditional agriculture practices in this region are adversely affected by water scarcity. The purpose of this study is to determine the most effective site for rainwater harvesting (RWH) through multi-criteria analysis combined with Geographic Information Sysytem. The decision-making criteria used in this study included rainfall, land cover, curve number, topographic wetness index, slope, distance from agriculture, lineament density, geology, and road and city distance. These criteria are categorized into five suitability levels based on their significance for rainwater harvesting using an analytical and hierarchical process (AHP). The study also mapped the restricted area, which includes the built-up area and water accounting for ≈6% of the total area. The area with very high suitability for RWH is ≈658 km2, representing 28.3% of the total area. The suitability model is validated by cross-checking existing RWH ponds with the appropriate map. It is found that most of the existing RWH ponds are located within high to moderately suitable zones, accounting for 92.6% of the total area. This research highlights the effectiveness of integrating MCA with GIS in identifying suitable RWH sites, especially in arid, semi-arid, and data-scarce areas. The weighted overlay process (WOP), available data, and methods are utilized to achieve this goal.