Identification of Optimal Rainwater Harvesting Sites in the Al-Karak Basin, Southern Jordan

This study aims to identify optimal rainwater harvesting (RWH) sites in the Al-Karak Basin, southern Jordan, with a focus on improving existing systems in arid and semi-arid regions (ASARs). These regions are increasingly affected by the impacts of climate change, including rising temperatures, declining rainfall, and higher evaporation rates. Such factors reduce water retention capacity and compromise the long-term effectiveness of RWH systems. Advanced analytical tools were employed to simulate runoff and generate RWH suitability maps, supported by detailed two- and three-dimensional (2D/3D) reservoir analyses. The Soil and Water Assessment Tool (SWAT) was calibrated and validated using observed discharge data from 2010 to 2017 using the SWAT-CUP tool. Calibration and validation results indicate robust model performance, with NSE and R2 values of 0.65 and 0.66 and 0.74 and 0.84, respectively ?