HYDROGEOLOGICAL INVESTIGATIONS OF THE GROUNDWATER RESOURCES IN WAJID AQUIFER SYSTEM, SOUTH WESTERN PART OF SAUDI ARABIA: APPLYING HYDROGEOCHEMICAL, GROUNDWATER MODELING AND ISOTOPES TECHNIQUES

Abstract

According to National Water Strategy MoEWA, 2021, Saudi Arabia water requirements were estimated in 2015 to be about 24.8 billion cubic meters with a constant annual increase of 7% with the agriculture sector being the largest consumer of water in the Kingdom (84% of the total water demand). Nowdays, water use in the agricultural sector reflects an socio-environmental challenge due to its dependence on non-renewable resources, which represent 90% of the total water supplied to this sector. Since the beginning of the agricultural development in the early 1980s, the natural flow system within the study area, particularly in the most prolific Wajid aquifer, has been altered considerably, mainly due to massive groundwater abstractions within the area of Wadi Ad Dawasir. The last comprehensive groundwater study covering the study area dates back to a period that preceded the agricultural development. The present work was compiled by examining all relevant data that have become available since the last studies. Thus, it provides the basic framework for the mathematical groundwater model to be developed within the scope of this work. The Wajid Aquifer System is one of the most important groundwater aquifers in Saudi Arabia. Data obtained from deep exploratory wells suggests that the aquifer system extends over a much larger area than estimated. The subsurface extent of the sandstones reaches the eastern shores of the Arabian Peninsula.