CLIMATE CHANGE IMPACT ON WATER RESOURCE IN MOROCCO; CASE OF ESSAOIURA BASIN

Since the 50s, many changes are observed in the global climate namely; the warming of the atmosphere and ocean, decrease in 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 and 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, accentuation the salinization of soils and water resources. The Essaouira Basin, object of this study, is located on the Atlantic coast of Morocco in the southeast of Essaouira city. This basin is characterized by a semi-arid climate with annual rainfall of around 300 mm / year and average temperatures of 20 ° C. Given the importance of the Essaouira aquifer in supplying drinking water to the city of Essaouira and neighboring communities, a study was done to quantitatively and qualitatively assess the impact of climate change on water resources. The aquifers characterizing this area are the Cenomanian-Turonian in upstream and Plio-Quaternary in downstream separated by the diapir Tidzi. The piezometric maps were made (1990-2015). The study of the chemistry of water shows that they have type facies Na-Cl (1990-2009), Mg-Cl and Cl (2015). The salinity varies from 80-3500 mg / L. 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 home is entirely dependent on rainwater.