Morocco's coastal aquifers: Recent observations, evolution and perspectives towards sustainability

During the last decades, the coastal areas of Morocco have witnessed an intense socioeconomic development associated with a continuous population growth and urban extension. This has led to an overexploitation of coastal aquifers leading to a degradation of their water quality. In order to obtain large scale overview on the quality status of Morocco's coastal aquifers (MCA) to assist national water managers to make informed decisions, a comprehensive scrutinization of the MCA against common indicators and using unified methods is essential. In this study, databases from thirteen MCA were analyzed, using multivariate statistical approaches and graphical methods in order to investigate the degree of mineralization in each aquifer and to identify the main salinization processes prevailing in groundwater. The results showed that the dominant groundwater types are Na-Cl, Ca-Mg-Cl, Ca-Mg-SO4, Ca-Mg-HCO3 and Ca-HCO3-Cl. The Gibbs diagram and the seawater contribution (0-37%) indicate that the mineralization is mainly due to the seawater intrusion and water-rock interaction. The salinity degree diagram illustrates that almost all groundwater samples are located in the moderate to very saline zone, indicating that MCA are recharged by water from variable sources. The groundwater quality assessment shows a deterioration, particularly by seawater intrusion and significant nitrate pollution. The temporal evo-lution confirm that the MCA are influenced by seawater namely in the Atlantic part. The Wilcox and USSL di-agram indicate that the majority of sampled water are unsuitable for irrigation uses. In addition, and by referring to the WHO and the Moroccan standards for water potability, large number of samples from the groundwaters of the MCA is not fully adequate for drinking purposes. A set of management actions (e,g., artificial recharge) are proposed in order to mitigate the effect of groundwater overexploitation and seawater intrusion to ensure the sustainability of MCA.

Automated summary

Coastal areas of Morocco have experienced intense socioeconomic development, leading to overexploitation of coastal aquifers and degradation of water quality. The study analyzed databases from thirteen MCA using statistical methods to investigate mineralization and salinization processes. Results showed that groundwater in MCA is mainly affected by seawater intrusion and water-rock interaction, with most samples located in the moderate to very saline zone. Actions such as artificial recharge are proposed to mitigate groundwater overexploitation and ensure sustainability.