Vulnerability and impact of climate change processes on water resource in semi-arid areas: In Essaouira basin (Morocco)

Abstract

Since the 50s, many changes are observed in the global climate namely; the warming of the atmosphere and ocean decreased the extent of snow and ice, and rising sea levels. In addition to population pressure, the Maghreb countries suffer from drought, which accentuates the phenomenon of desertification; soil erosion and salinity, leading to salinization and depletion of water resources. In Morocco, climate change causes soil erosion as a result of desertification resulting in siltation of dams, worsening of salinization soles and water resources. The Essaouira Basin the subject of this study focuses on the Atlantic coast of Morocco in the southeast of the city of Essaouira. Climate aridity and intensive exploitation due to uncontrolled pumping for irrigation have caused a drastic decrease in the piezometric level of the aquifers in Essaouira basin, and have seriously degraded groundwater quality. This basin is characterized by a semi-arid climate with average annual rainfall of around 300 mm/year and temperatures average 20 °C. Considering the importance of the Essaouira aquifer in the supply of the region in groundwater, a study was done to quantitatively and qualitatively assess the impact of climate change on water resources in the area. Aquifers characterizing this area are Cenomanian-Turonian of the upstream and downstream Plio-Quaternary, separated by the Tidzi diaper. The piezometric maps pelvis were made (90-09). Geochemistry shows that these present Sodium-chloride facies. The electrical conductivity ranges from 700–7000 μS/cm. The concentration of 18O; 2H; 3H and 14C were measured, a local meteoric right close to the global meteoric right characterizing ocean precipitation was determined and the age of groundwater is determined. The Essaouira Basin is very vulnerable and sensitive to climate change because its charge is entirely dependent on rainwater.