HYDROGEOLOGICAL INVESTIGATIONS IN BASEMENT TERRAINS USING GEOLOGICAL, GEOMOR-PHOLOGICAL AND GEOPHYSICAL METHODS, WESTERN HAMISSANA AREA, NE SUDAN

Abstract

This study aims at identifying target zones for groundwater exploration in basement terrains using geological, geomorphological, and geoelectrical methods. The study area is located on the northwestern side of the Red Sea Hills in the western Hamissana area. It is part of the Arabian Nubian Shield (ANS), which dates to the Pan-African Era. The study area is covered by Precambrian basement rocks which are overlain by alluvial deposits. The climate in the region is arid. As a result, severe water shortage is experienced. The geological and geomorphological investigations were carried out to locate potential sites for groundwater prospecting. On this basis, three categories of groundwater potential zones were delineated as good, moderate, or poor. The electrical resistivity method using vertical electrical sounding (VES) technique was used to determine the vertical geological profile of the study area. The sequence was revealed to consist of four zones: a high-resistance unsaturated zone, an intermediate-resistance water-bearing formation, a low-resistance wet weathered basement, and high-resistance fresh basement rock. Catchment boundaries were delineated using digital elevation models, and potential locations for surface and subsurface dams were proposed to improve the groundwater recharge.