GIS-based multifactor analysis for positioning water harvesting sites integrated with managed aquifer recharge

Abstract

Runoff loss to the sea and seawater intrusion into coastal aquifers represents a dual hydrologic phenomenon in many coastal regions, and the coastal zone of Lebanon is a typical example. In this respect, an integrated management approach must be adopted to mitigate the impact of this geo-environmental problem through surface water harvesting and recharging (SWHR) into the beneath rock formations. However, positioning suitable sites, for surface water harvesting, from which water can be artificially/spontaneously recharged, is often a challenging. This study handles this challenge with innovative multi factor method using GIS to identify the optimal sites for SWHR. For this purpose, thematic maps were analyzed and systematically integrated, while data retrieved was mainly from satellite images (e.g., Sentinel-2, SRTM, etc.). The obtained geospatial data represent main factors controlling surface water flow regime, infiltration potential and other relevant environmental factors. Being converted to GIS digital files with various levels of impact “weight coefficients” on SWHR, these factors were systematically manipulated; and thus 28 sites were identified and hydrologically characterized and 13 of them were emphasized as primary ones. The produced SWHR sites' map serves decision-makers to take proper actions for water management in coastal zones whether in the investment of surface water or the mitigation of seawater intrusion.