Quantitative and Qualitative Assessment of Groundwater from Semi-Arid Zones in the Context of Climate Change, Example of Essaouira Region, Morocco

Abstract

This study aims to assess the effect of climate change on water resources in semi-arid environments, taking the Essaouira region as an example. Analysis of climate data shows a downward trend in precipitation of 12 to 16% and an increase in air temperature of 2.3 °C over the past three decades. The piezometric study shows a continuous drop in the piezometric level which exceeds 12 m for the Cenomanian-Turonian aquifer, 17 m for the Plio-Quaternary aquifer, around 8 m for the Barremian-Aptian aquifer and 5 m for the Hauterivian. Hydrogeochemical analysis shows that (i) the groundwater mineralization is controlled by the dissolution of evaporitic and carbonates minerals, by the reverse ions exchange phenomenon, and by the marine intrusion, especially at Plio-Quaternary aquifer; (ii) the groundwater quality in the study area deteriorates gradually over time and space. The isotopic technique shows that (i) the groundwater recharge in the study area is ensured by precipitation of oceanic origin without significant evaporation and that (ii) climate change has no remarkable effect on the isotopic content of the groundwater of the study area. However, the results of this article reflect that the Essaouira basin is very vulnerable to climate change.