The use of remote sensing for water protection in the karst environment of the tabular middle Atlas/the causse of El Hajeb/Morocco

Deep water bodies constitute the strategic water reserves of Morocco. These natural resources are used in many activities such as irrigation in agriculture, and, more importantly, they are the source of fresh drinking water for the local population. However, these resources are vulnerable to anthropogenic and natural phenomena due to ongoing climate change and the increase in population growth. To contribute to the recent initiative for the protection of the karstic environment of water springs in the Tabular Middle Atlas of El Hajeb, the present research work aims to characterize different karst landforms in Liassic carbonate rocks of the Tabular Middle Atlas in the Causse of El Hajeb, where pollution identified in water samples in this region originates. Satellite imagery (Sentinel-2, Landsat, Terra-ASTER, ASTER-GDEM) and GIS tools were used. Based on surface reflectance of dolomite and limestone, especially in shortwave infrared, we delineated the extent of carbonate rocks and areas with intense human activities. Fractures affecting these Liassic rocks were extracted mechanically and manually after the application of Sobel operator filter in N, S, NE and SW main directions. The results show an improvement and a better understanding of the hydrogeological system of this karst environment, in particular the location of new faults identified in NESW and NW-SE fault systems which involve infiltration of surface water and groundwater drainage respectively. The percolation of slightly acidic water through these fractures has gradually created cavities and sinkholes which are believed to be the origin of turbidity observed during the analysis of the water springs.