Evaluation of climate change impact on groundwater from semi-arid environment (Essaouira Basin, Morocco) using integrated approaches

The water resource is one of the main bases for the economic development of such a country. In recent decades, this resource has experienced a qualitative and quantitative degradation under the effect of global warming, especially in zones under arid and semi-arid climate as the case of Morocco. A better understanding of the relationship between climate change and its impacts on the availability of water resources involves a climatological analysis (rainfall and temperature), a piezometric, hydrogeochemical, and isotopic approach. In this investigation, the area taken as an example is the Essaouira Basin. Trend analysis of rainfall and temperature series shows that rainfall and temperature show a downward trend of 12% and an upward trend of 0.9 (for the period 1950-2015) to 1.5 degrees C (for the period 1988-2004), respectively. The piezometric study shows a downward trend following the shortening of recharge periods and recurrent drought. The hydrogeochemical approach indicates a deterioration of groundwater quality with an increase in salinity. This degradation is due to the marine intrusion and to the decrease of the recharge rate of aquifers caused by the decrease of precipitations under the climate change effect. The isotopic approach shows that climate change has no effect on the isotopic content of the groundwater in the study area.