Hydrogeology of a Complex Aquifer System in Semi-Arid Mountainous Region: The Eastern Upper Guir Basin in the High Atlas (Morocco)

Abstract

The eastern part of Morocco, surrounded by the High Atlas chain close to Errachidia, represents a very sensitive area in a semi-arid context. Average annual rainfall does not exceed 300 mm/year. Most of the regional water resources are linked to the aquifer systems in the Atlas area. The study site coincides with the Eastern Upper Guir Basin, one of the main rivers in Eastern Morocco. This basin is located close to the eastern border of the Moroccan High Atlas. The geology of the basin consists mainly of Jurassic and Cretaceous formations. The structure of the basin is strongly affected by the Atlasian tectonics. This results in successive large synclines separated by major W-E faults. The hydrogeological system of the basin is accordingly constituted by sub-basins associated with each syncline and separated by faulted anticlines, whose overlapping faults act as semi-impermeable barriers. This compartmentalization causes the very complex functioning of the whole system. The study undertaken, based on structural, meteorological, hydrogeological, hydrochemical and isotopic data, allowed us to advance significantly in the understanding of this system. The compartments behave as hydrogeological sub-units but remain interdependent on each other. The recharge of the aquifer system is essentially associated with the rains and snowfalls at high altitudes. This is consistent with the stable isotope results. Important development projects are planned in this region, associated with a drastic increase in water demands. Groundwater suitability was assessed using the WHO standards for drinking purposes and the SAR (sodium adsorption ratio) for irrigation. Complementary investigations should be considered to further the results presented here and move towards a quantitative assessment and management of the water resources.

Exploring the land use and land cover change in the period 2005–2020 in the province of Errachidia, the pre-sahara of Morocco

“…It plays also a recharge role for the southern part of the Jurassic aquifer of the High Atlas (Ben-said et al, 2017). The groundwater of the Tafilalet is a considerable water resource (Bouaamlat et al, 2016) and the aquifer recharge is basically related to the high altitudes precipitations (Abdelfadel et al, 2020). Rainfall events in the High Atlas are also in the origin of frequent fluvial sediment driven towards the Tafilalt Basin (Herzog et al, 2021).…”

“…More particularly, the Errachidia province is understudied in terms of the application of LULC, NDVI, NDWI, and EVI. The most recent relevant study conducted in the area on water resources was about the hydrogeology of a complex aquifer system in the Upper Guir Basin near Errachidia (Abdelfadel et al, 2020). Using field measurements and descriptive statistics, this last study recommended the orientation to quantitative assessment of the water resources.…”

Hydrochemical evolution and groundwater quality assessment of the Tinejdad-Touroug quaternary aquifer, South-East Morocco

“…Considering the importance of groundwater resources in southern Morocco, scientists have recently conducted a considerable amount of research to study the hydrogeological and hydrogeochemical features of the adjacent regions. These include papers on the Ziz basin by (Lgourna et al, 2015;Roubil et al, 2022), Guir basin by (Abdelfadel et al, 2020) the Middle Ziz aquifer by (Mehdaoui et al, 2019), and the Tafilalet plain by (Bouaamlat et al, 2016;El Ouali et al, 2023). Therefore, the quality of groundwater in the Tinejdad-Touroug region was investigated in this study in order to assess its suitability for domestic and irrigation purposes.…”