GIS-Based Multi-Criteria Analysis for Identifying Suitable Rainwater Harvesting Sites to Enhance Groundwater Recharge: A Case Study of the Western Wellfield in Thaqban Area, Sana’a, Yemen

Groundwater depletion in the Sana’a Basin, Yemen, has intensified due to over-abstraction, rapid urbanization, and limited natural recharge. The Western Wellfield, which supplies a significant portion of Sana’a City’s domestic water demand, has experienced substantial groundwater level declines, highlighting the need for sustainable recharge interventions. This study evaluates the potential of rainwater harvesting (RWH) for enhancing groundwater recharge in the Thaqban area using a Geographic Information System (GIS)-based Multi Criteria Decision Analysis (MCDA) integrated with the Analytic Hierarchy Process (AHP). Ten thematic criteria were considered, including rainfall, runoff depth, slope, geological media, soil texture, land use/land cover, drainage density, distance to wadis, distance to groundwater wells, and groundwater depth. The criteria were weighted using AHP and combined through a weighted linear combination (WLC) approach to generate an RWH suitability map. The results show that 1.34% of the study area is highly suitable for RWH implementation, 37.60% is moderately suitable, 58.21% is marginally suitable, and 2.85% is unsuitable. Highly suitable areas are mainly associated with permeable geological formations, favorable topography, and proximity to production wells. This study demonstrates the usefulness of GIS-MCDA techniques for identifying priority recharge zones and supporting sustainable groundwater management in arid environments.