Assessment of Groundwater Resources in the Hard Basement Rocks of Yemen, Al Bayda City Case Study

Abstract

The present study was carried out with the aim of assessing the availability of groundwater in a typical hard basement complex area in Yemen, the catchment area of Al-Bayda city catchment in the mountainous region of the country. The main objective of this study is to evaluate and quantify the groundwater resources available in this area. The available regional data on climate, topography, and geology as well as ASTER and Landsat imaginary data were collected, reviewed, and analyzed together with local hydrogeological studies and well inventories and then used to identify the general geohydrology of the catchment, characterize the local aquifer system, assess the groundwater situation and quantify the available groundwater in the study area. The results of this study show that the aquifer system accounts for only about 5 % of the entire catchment area and has a total thickness of 10 - 30 m. This aquifer has a small lateral extent and is interrupted by faults, dykes, and plutonic intrusions. Limited amounts of groundwater occur in isolated bodies along the main wadis at the base of the aquifer system. The groundwater level in these bodies has dropped by 19 m since 1983, on average by 0.5 m per year. Groundwater recharge for the current state is estimated at 1.95 million m3/year, which is only 3% of the total annual precipitation. The total amount of groundwater withdrawn is estimated at 2.2 million m3/year, which is 80% below the current (2023) total annual demand of around 11 million m3. The study underlines the need to implement an urgent action plan to improve groundwater recharge through water extraction techniques. The research results can be used for the improvement and development of water resources in this area in particular and in the Yemen region in general.