Multi-criteria decision support system for selecting the rainwater harvesting technique in wadi systems, Sinai, Egypt

Recently, some areas are exposed to water scarcity and floods, and rainwater harvesting (RWH) is a practical solution, particularly in arid and semi-arid regions. The Wadi Watier basin located in South Sinai, Egypt was selected to identify the appropriate RWH techniques. Five alternatives were proposed: a dam with a reservoir, a storage pond, an underground tank, wadi bed cultivation, or a Jessor system. The hydrological model was built using the WMS software to determine the runoff volume at the proposed RWH sites. Multiple criteria were identified and classified based on their suitability degree. Then, an Analytic Hierarchy Process (AHP) was used to assign the effective weight of each evaluation criterion. The AHP revealed that the wadi slope and initial cost have the highest evaluation influence of 20%, followed by the wadi width of 15%. The rainfall volume, social acceptance, and cost revenue have moderate influences with weights from 8 to 11%. Finally, the storage ponds and underground tanks recorded the highest suitability evaluations at the selected RWH sites, at 65.4 and 62.7%, respectively. The dam with a reservoir recorded 49.3%, which is considered medium suitability, while wadi bed cultivation and Jessor systems were classified as low suitability evaluations with 42.7 and 41.7%, respectively.