Abstract
Abstract The Nubian Sandstone Aquifer System (NSAS) is one of the largest aquifer systems in the world, covering approximately 2.2 million km2 in Northeast Africa. It extends for over 1,500 km in the East-West direction and 1800 km in the North-South direction across Chad, Egypt, Libya, and Sudan. Near the oasis of Kufra, NSAS reaches a maximum thickness of more than 4000 m. The hydraulic head ranges from 570 m above sea level west of Darfur to 78 m in the Qattara depression. The total volume of freshwater stored in the NSAS was estimated at 450,000 km3, of which around 14,000 km3 are recoverable. Thirty years ago, the four NSAS countries laid the building blocks for cooperation in managing the shared aquifer system. Egypt and Libya started the process in the early 1980s and culminated in 1991 with the establishment of the Joint Authority for the Study and Development of NSAS (JA-NSAS). The constitution of the Joint Authority was adopted in 1992. Sudan joined the Joint Authority in 1996, and Chad followed suit in 1999, making all riparian states members of JA-NSAS and abiding by the principles of the joint management of this important transboundary basin. The functions of JA-NSAS include the periodic collection of field data, carrying out supplementary studies on the state of the aquifer, preparing plans for water resource development, proposing and implementing joint policies for the rational utilization of water resources and assessing their environmental impacts at the national and regional levels, and organizing training courses and capacity building. Over the past 30 years, more than 30 meetings of the Board of Directors have been held to set general policies and follow up the activities of the subsidiary offices in the Member States. International and regional organizations such as IFAD, UNESCO, IAEA, IDB, GEF were approached for funding regional hydrogeological studies and devising strategies for the sustainable exploitation of the shared aquifers, elaborating socio-economic studies, updating the mathematical model and database, and preparing a Strategic Action Program. Major steps have been taken thus far to enhance institutional capacity and secure the flow of technical information. They include establishing a common network of production and monitoring wells, developing mathematical models capable of simulating various exploitation scenarios, and signing a protocol for monitoring and exchanging groundwater information. Data on annual extraction, water quality and water levels from the regional monitoring network, as well as the socio-economic and environmental data and drilling results are systematically entered into the Nubian Aquifer Regional Information System (NARIS). Keywords: Nubian Sandstone Aquifer System, Joint Authority, Transboundary Aquifers, Groundwater Management.