Geospatial techniques for identifying optimal rainwater harvesting sites to enhance agricultural productivity in hyper arid areas

The increasing demand for freshwater, combined with limited availability and the exacerbating effects of climate change, poses significant global challenges to sustainable water supply. Addressing the widening gap between water supply and demand necessitates the adoption of innovative and sustainable water management strategies. As a renewable and locally available resource, rainwater holds considerable potential to alleviate water scarcity in arid and semi-arid regions. This study explores rainwater harvesting (RWH) as a practical strategy to address the annual groundwater deficit in the State of Qatar. A Geographic Information System (GIS)-based approach was employed to assess the potential of RWH implementation. The analysis integrated ground-based observations with satellite-derived datasets to identify suitable locations for RWH. To enhance the accuracy of the suitability mapping, legal constraints such as urban areas, parks, and farms as well as protective buffer zones were applied, resulting in a refined delineation of land realistically available for RWH development. The findings indicate that approximately 59 % of Qatar's land area is potentially suitable for RWH initiatives. Of this, 1.27 % was classified as 'very highly suitable', 27.27 % as 'highly suitable', and 49.50 % as 'moderately suitable'. Assuming the installation of engineered RWH wells with a recharge efficiency of 40 % and annual rainfall of 67 mm, the estimated net groundwater recharge from these three suitability classes could reach approximately 107 million m³ annually. These results highlight the substantial contribution that RWH can potentially make toward reducing Qatar's national freshwater deficit. The outcomes of this research support the strategic expansion of RWH infrastructure and provide a basis for informed decision-making in future water resource planning across the country.