Multi-criteria analysis using satellite images and the GIS for mapping groundwater recharge zones in Saudi Arabia: a case study of the Riyadh Region

Water scarcity is well pronounced in arid and semiarid regions where potential evapotranspiration exceeds precipitation. Saudi Arabia is one of the most water-scarce regions worldwide where there are only 2 billion m3 of annual renewable freshwater resources, besides 24 billion m3 of freshwater withdrawal, especially from the aquifers with fossil water. In Saudi Arabia, floods often occur and the harvest of flood water for groundwater recharge became an issue of discussion; however, this requires determining groundwater recharge potential (GWRP) zones where water naturally percolates and feeds the depleted aquifers. This study aims to produce a detailed (digital) map for GWRP zones for the Riyadh Region by using a multicriteria approach where datasets were derived from satellite images (Landsat 7 ETM+, Spot-5, and Aster) associated with thematic maps and field surveys. The geo-information system (GIS) was also used to manipulate and integrate the geospatial data layers which represent the controlling factors on GWRP. Results show five classes of GWRP zones, where about 36,448 km2 (89.2% of the Riyadh Region) belong to high and very high GWRP. The resulting map will be key information for decision-makers to select suitable localities for groundwater artificial recharge techniques as an adaptive measure for the changing climate.