Hydrodynamic characterization of karst springs: case of Ras El Maa Spring (Northern Rif, Morocco)
In Morocco, the issue of water resources arises with clarity. In the 1960s, the Moroccan state adopted a strategy for the development and protection of this valuable resource. However, difficulties in water management increased as a result of demographic pressure on water resources, leading to problems of water scarcity in many areas of the Kingdom, especially in low-rainfall areas. The main objective of this study was to obtain a better knowledge of the hydrodynamic functioning of the karst aquifers that are found southeast of the city of Chefchaouen (northern Morocco). In this region, the karst groundwater is important for drinking water supply and irrigation. From the hydrogeological point of view, the karstic springs that are the subject of this study have considerable flows, which can exceed the 100 L•s-1 during flood periods. Aquifer recharge occurs primarily by rainwater and to some extent by snowmelt in the mountain peaks (for example the peak of Jbel Lakraa at 2,159 m, and that of Jbel Tissouka at 2,122 m). The springs with the greatest flow occur at the lower altitudes, especially at the dorsal-flysch contacts. The hydrodynamic functioning of the Ras El Maa, Maggo and Chrafate springs showed a very inertial, poorly drained and poorly karstified system. The Maggo springs present a very high recession coefficient, which is likely due to the presence of karstic cavities in the Jbel Lakraâ massif. The total volume of the groundwater reserves, obtained from the recession curves of the four springs, is approximately 10 million m3. Nevertheless the dynamic volumes from the Ras El Maa spring alone constitute 5 million m3.