HYDROGEOLOGICAL CHARACTERISTICS AND GROUNDWATER ORIGIN OF THE MIDDLE EOCENE FRACTURED CARBONATE AQUIFERS AT WADI EL TARFA BASIN, EASTERN DESERT, EGYPT

Groundwater represents the main source of water supply in Wadi El Tarfa area. Wadi El Tarfa is one of the largest basins in the Eastern Desert which located east of the Nile River and has a surface area reaches 4939 Km. The geologic setting plays a vital role in groundwater occurrences, quantity and quality. The evaluation of the groundwater resources at Wadi El Tarfa has been achieved through the detailed studies of geomorphological, geological, hydrogeological and hydrogeochemical characteristics. The groundwater is available from two water bearing formations; Maghagha marly limestone aquifer and Samalut limestone aquifer which occur under free water table conditions. The groundwater of Maghagha aquifer is recorded at depth ranges from 38.95 m to 59.27 m and the salinity varies from 862.54 mg/l to 978.47 mg/l. The depth to the water of Samalut aquifer varies from 10 m to 80 m and the salinity ranges from 227.51 mg/l to 2545.11 mg/l. The transmissivity ranges from 19.82 m/day to 4125.60 m/day. The collected groundwater samples were chemically analyzed and interpreted. The groundwater origin has been determined through the stable isotope analysis for some selected samples. Finally, the best sites for groundwater exploitation from Samalut aquifer at Wadi El Tarfa basin have been determined.