Integrated Water Harvesting and Aquifer Recharge Evaluation Methodology Based on Remote Sensing and Geographical Information System: Case Study in Iraq

Water harvesting (WH) and aquifer recharge (AR) have been promoted in recent decades as solutions to the overexploitation of groundwater resources in many countries around the world. Remote sensing (RS) and geographic information system (GIS) technologies with multi-criteria decision analysis (MCDA) enable the analysis of many parameters to identify potential WH and AR sites and suitable zones for site-specific and cost-effective recharge structures. Iraq is located within an arid and semiarid region and thus suffers from water scarcity and absent surface water resources. The use of RS and GIS technology for detection of appropriate sites for WH and AR could potentially increase water availability. The criteria selected for determining appropriate WH and AR areas were runoff, drainage, geology, groundwater depth, slope, soil texture, and land use/land cover. The selection of these criteria was found to be more important and more frequent in a literature review for WH and AR, and the weightage of each criterion should be based on the opinion of experts. The obtained results indicated only five optimum sites for check dam construction for WH, due to their locations in suitable land class, slope (< 15%), and soil type (sandy clay loam) conducive to soil and water preservation and groundwater accretion. Six optimum sites were proposed for AR to build percolation tanks, due to their locations within the outcrops of the Al-Dammam and Um Erdhuma Formations because these formations contain fractures, which recharge groundwater directly. In addition, the selected sites were situated in sandy silt loam soils (which are highly appropriate for recharging groundwater systems) barren land with slope of < 10%, and second- and third-order drainages. These prevent damage to percolation tanks owing to high runoff rate. Many sites of wells and boreholes were chosen at outcrop locations of the Al-Dammam and Um Erdhuma Formations because of directly infiltrating runoff water into the aquifer and to decrease the velocity of runoff water and protect the check dam from corruption.