Geotechnical Assessment of Seepage and Rainwater Harvesting Feasibility at Beit Al Rush Earth Dam, Southwest Bank, Palestine

Abstract

Water scarcity in Palestine is becoming increasingly severe, as massive areas face semi-arid conditions due to extended droughts in the eastern Mediterranean region and limitations on water access. With limited surface and groundwater availability, earth dams have been considered a practical solution for water harvesting and have gained a mitigation strategy. This study presents a comprehensive geological and geotechnical evaluation of the Beit Al Rush earth dam, located in the southern West Bank in the Hebron Governorate. Despite initial expectations of storing 130,000 m³ of water annually, the dam failed shortly after construction due to complete water loss within days. To assess its feasibility for rainwater retention, integrated geotechnical fieldwork and laboratory analyses were conducted, including borehole drilling, trial pits, infiltration testing, and soil classification. GIS techniques were used to create spatial maps of geological features, watershed boundaries, and topographic elements. The geological review revealed that the dam site is located within karstified carbonate rock formations that are underlain by fractured marly limestone and covered by highly permeable alluvial soils. Hydrologically, the region receives an average annual rainfall of about 350 mm. The steep, rugged topography facilitates rapid surface runoff. Geotechnical results demonstrated high permeability rates (3.958 * 10-3 cm/sec) in surface soils and bedrock layers, confirming the site's unsuitability for effective water retention. The study recommends remedial measures, including grouting fractured zones, applying impermeable liners, and improving compaction to enhance storage capacity. These findings emphasize the critical role and importance of geological and geotechnical