A General Study of the Water Resources Aquifer System Ghadames and Murzuq Basins - Libya

الملخص

The Murzuq and Ghadames Basins region, located in southwest Libya. Both basins are of high importance for hydrogeological systems, in North African Aquifer System Figure1. Bounded by Tibisti-Al Haruj to the east and Hoggar to the west, with extensions into Niger as the Djado Basin and Nafusa Uplift in the north. Both basins' surfaces are characterized by arid climatic conditions, experiencing extreme temperatures, minimal rainfall, and occasional torrential storms, underscoring the importance of their groundwater resources for sustainability.
Ghadames Basin is part of the Northwestern Sahara Aquifer System extends across Libya, Tunisia, and Algeria, highlighting its significance as a transboundary water resource.
The aquifer systems in the two basins encompass a variety of geological formations. The Murzuq Basin contains Upper, Middle, and Lower aquifers, ranging from Cambro-Ordovician to Cretaceous formations, with the Nubian and Post-Tassilian aquifers being extensively utilized for irrigation and domestic use. Similarly, the Ghadames Basin features the Senonian, Eocene limestone, and Turonian aquifers, which provide critical water supplies, but with varying mineralization and recharge dynamics influenced generally by geological and climatic factors. Hydrogeological assessments for both basins reveal significant variations in transmissivity, water table depth, and storage coefficients, showcasing ancient groundwater isotopic signatures indicative of minimal recent recharge.
Hydro-chemical analyses highlight diverse water qualities across both basins. In the Murzuq Basin, groundwater ranges from fresh to moderately saline, with Na-Cl and Mixed-HCO3 facies predominating, while the Ghadames Basin displays mineralization gradients linked to more recent recharge zones and the salinity challenges near areas like Oued Rhir and Ouargla. Both basins face significant challenges, including declining water levels, salinity intrusion, and contamination risks due to uncontrolled groundwater extraction and agricultural activities. In the Ghadames Basin, the impacts of large-scale projects like the Great Man-Made River further strain the non-renewable groundwater resources.
This study provides a regional comprehensive review of the hydrogeological and hydro-chemical characteristics of both Murzuq and Ghadames Basins, emphasizing the need for integrated, sustainable water management strategies and transboundary cooperation, particularly in the Ghadames Basin. Advanced monitoring, alternative water sources, and policy reforms are critical to mitigating over-extraction and ensuring the long-term viability of these vital water resources.