DELINEATING GROUNDWATER POTENTIAL ZONES IN JAZAN REGION, SAUDI ARABIA: A GIS AND REMOTE SENSING APPROACH USING ANALYTIC HIERARCHY PROCESS

Abstract

In arid countries such as Saudi Arabia, groundwater is an essential source of fresh water. The Jazan region is one of the Saudi Arabian regions and has the highest population density in the country. This region relies on groundwater as a source of fresh water, and the demand for this source has increased by 11,000 m3/day over the past 13 years. To meet this demand, identifying groundwater potential zones (GWPZ) becomes crucial. This dissertation aims to delineate GWPZ in 94% of the Jazan region using remote sensing, GIS, and the analytic hierarchy process (AHP), and ten thematic layers were generated for this purpose. Notably, incorrect classification and ranking of vegetation and water spectral indices (e.g., NDVI, NDWI, and NDMI) and a spatial correlation between them and the LULC thematic layer were observed in recent published studies. To address this, two thematic layers, CVWI (a combination of these indices) and MLULC (CVWI merged with land use/ land cover), were suggested. Two methods, AHP and weighted overlay analysis, were conducted, resulting in two GWPZ maps that were validated against regional observation well data. Findings revealed that merging vegetation and water indices with land use/ land cover in a single thematic layer yielded a better performing model compared to using them separately in the overlay analysis. It was determined that 62% of the study area in the Jazan region is categorised as a high potential zone. This differed from earlier studies, which allocated more area to zones of very high potential.