Targeting runoff hotspots for sustainable rainwater harvesting in arid regions

Rainwater harvesting (RWH) is a crucial strategy for enhancing water availability in arid regions and supporting local livelihoods, including those of Bedouin communities. Rainwater. This study focuses on Wadi Sudr, located opposite Ras Sudr city in the Sinai Peninsula, to identify optimal RWH sites and recommend suitable harvesting techniques. A weighted spatial probability model (WSPM) was developed within a Geographic Information System (GIS) framework, incorporating eight morphometric parameters. Two scenarios were evaluated: 1) equal weighting of all factors and 2) analytical hierarchy process (AHP) based weighting. The resulting maps classified the watershed into five RWH potential categories. Scenario 1 (equal weighting) identified 49.6% of the area as high or very high potential. In contrast, Scenario 2 (AHP-based) refined this to 18.2%, emphasising the role of basin shape, slope, and valley floor area. High- and very high-priority zones guided recommendations for two surface storage dams in Al-Mleha, with capacities of 25,000–30,000 m³, and Al-Athamy, with capacities of 70,000–80,000 m³, sub-catchments, complemented by cisterns to support remote communities. By integrating GIS, WSPM, and AHP into a unified framework, this study delivers a replicable methodology for prioritising RWH in arid regions, balancing efficiency with accessibility to strengthen sustainable water resource management.