Contribution to the Hydrogeochemical and Bacteriological Knowledge of the Aquifer Systems of the EL Oued Area (Northern Rif, Morocco)

The study is the first in the El Oued region. It was based on a descriptive statistical approach to analyze and process hydrogeochemical and bacteriological data of groundwater draining detrital and carbonate sedimentary geological formations to develop water quality classes for the aquifers in the study area and to valorize them. The study area is in northern Morocco, in the northern Rif. The latter is a part of the Flyschs aquifer and a part of the Calcareous-Dorsal of the Rif chain southeast of the Tetouan city. The principal Calcareous-Dolomitic and detrital geomorphic unit formations provide an important reservoir in the study area. Recharge of these aquifers is deeply linked to the direct precipitation. The atomic spectrometry and the titrimetric methods analyzed fifteen groundwater samples from springs, boreholes, and hand-dug wells. They were the subject of a physical–chemical (EC, temperature, pH) measurement in situ, a chemical-bacteriological analysis (Ca2+, Na+, K+, Mg2+, TAC, TDS, Cl−, HCO3−, SO42−, NO3−, fecal coliforms) in the laboratory, and a hydrochemical study. The aquifers in the study area are generally of two types: fissured aquifers and porous media aquifers. The physicochemical and bacteriological data show that the water in the aquifer system of the study area was generally clear of Nitrate and of excellent to very good quality. These results were confirmed by the Water Quality Index (WQI ≤ 41.46) and the Principal Component Analysis (PCA). Three geochemical water facies were distinguished: a calcium chloride dominated water (Numidian Flysch), a calcium bicarbonate dominated water and a calcium magnesium bicarbonate dominated water (Beni Ider Flysch, Limestone and Dolostone). Based on the Electric Conductivity (EC) and the sodium percentage (%Na) classification, 93.34% of the water samples were considered excellent and 6.66% were considered as good for irrigation purposes. While, based on the EC and the SAR classification, 26.7% and 73.3% of groundwater samples indicate excellent and a good to somewhat good water quality, respectively.