Assessment and modeling of surface water quality for drinking and irrigation purposes using water quality indices and GIS techniques in the Inaouene watershed, Morocco

Water scarcity and environmental degradation are among the primary challenges in arid and semi-arid regions, such as Morocco. This study aimed to assess the quality of surface waters in Inaouene, considering their potential use for human consumption and irrigation, by incorporating water quality indices into a Geographic Information System. To achieve this, water samples were collected during the wet seasons, followed by the examination of 26 physico-chemical and bacteriological parameters. The results revealed spatial variations in the parameters studied compared to the standards established by the World Health Organization. Water quality upstream of the watershed is influenced by urban and industrial discharges, while it improves downstream due to dilution by other tributaries. The chemical analysis uncovered various facies within the watershed. In the east, it exhibits a chlorinated-sodium nature, transitioning to chlorinated-sulfate and calcic-magnesian facies. In the west, it corresponds to bicarbonate calcic and magnesian facies. According to the analysis of the Water Quality Index, the waters have been divided into two categories, one corresponding to the sample Ech1, indicating poor water quality, while the remaining stations have good water quality. The Irrigation Water Quality Index was employed to evaluate the quality of water designated for irrigation through the analysis of various parameters. The results indicated that most of the samples displayed low restriction. However, sample Ech1 was classified as having severe restriction. Using a combination of different indices is proving effective in providing accurate information on the water quality of Oued Inaouene in northern Morocco.