The aim of this present study was to evaluate groundwater quality in the upstream part of the Essaouira basin. A detailed geochemical study of groundwater region is described, and the origin of the chemical composition of groundwater has been qualitatively evaluated, using multivariate statistical methods (PCA, HCA), and Water Quality Index (WQI) was used to determine the suitability of water for drinking. To attempt this investigation, 38 samples were analysed for various physicochemical parameters such as temperature, pH, TDS, Na, NO₃, K, Ca, HCO₃, Cl, Mg, and SO₄. The results obtained showed that the facies characterizing the study area was a combination of Ca–SO₄ and mixed Ca–Mg–Cl. Hydrochemical approach based on the bivariate diagrams of major ions indicates that the origins of groundwater mineralization are the result of (I) evaporite dissolution; (II) cation-exchange reactions; and (III) evaporation processes. The WQI values range from 82.3 to 390.9, and therefore the water samples can be categorized into five groups: excellent water to water unsuitable for drinking. In global, 61% of the groundwater sampled had poor water quality, 18% were very poor water quality, 16% are unsuitable for drinking, and just 6% represent a good quality. However, the results of this paper indicate that most water is not safe for drinking and needs further treatment.

In this study, hydrogeochemical analyses were combined with geographic information system (GIS) tools to investigate salinization sources of groundwater in the downstream part of the Essaouira basin, and to analyze the spatiotemporal trends in groundwater quality. To assess groundwater suitability for drinking purposes, the quality of sampled water was compared with the World Health Organization (WHO) and the Moroccan guidelines. Wilcox and US salinity laboratory (USSL) diagrams were used to evaluate groundwater suitability for irrigation. Hydrogeochemical analyses revealed that groundwater is of Na-Cl and Ca-Mg-Cl types. The analyses of the correlation between the chemical elements showed that the water–rock interaction and the reverse ion exchange are the major processes impacting groundwater degradation in the study area. The study of groundwater suitability for drinking and irrigation purposes shows that groundwater quality in the study area is permissible, but not desirable for human consumption. Additionally, groundwater is permissible for agricultural use but with high-salinity hazards. The spatial distribution of the physicochemical elements shows a general upward gradient from the north to the south and from the east to the west. The trend in groundwater quality during the last five years shows a shifting in the quality from the mixed Ca-Mg-Cl to the Na-Cl type.

The 2030 Agenda for Sustainable Development aims to reach 17 Sustainable Development Goals (SDGs). The SDGs 6 deals with water security, which refers mainly to ensure availability and sus-tainable management of water. The present study aims to enhance reservoir performance under climate change to deal with water scarcity. For this purpose, we proposed a new methodology where precipitation and evaporation data provided through temporal downscaling are leveraged by a real-time management algorithm coupled with the Hydrologic Modeling System (HEC-HMS). The real-time dam management algorithm is based on water balance equation and rule curves. It provides information about (1) dam storage, (2) dam release, (3) dam evaporation, (4) dam diversion, (5) spilled water volume, (6) emergency spilled water volume, (7) dam inflow, (8) irrigation demand, (9) irrigation shortage, (10) dam siltation, (11) dam hydropower produc-tion, (12) hydropower energy income. The developed approach has been applied to the Hassan Addakhil multipurpose reservoir in Morocco. The result shows that the dam reliability and resili-ence have increased from 40% to 70% and from 16% to 66%, respectively, while the vulnerability remained constant. Additionally, this study has pointed out that the installation of a hydropower plant is an opportunity to produce clean electrical energy and generate an income enough to cov-er different costs related to dam management and maintenance. Therefore, the real-time man-agement tool developed in the framework of this project can significantly enhance reservoir per-formance.

Groundwater resources are becoming increasingly vulnerable to human activities and climate change due to high water demand, intensive abstraction, and increased evapotranspiration associated with changes in precipitation amounts and patterns. In semi-arid mountain watersheds, groundwater recharge estimation is affected by substantial uncertainty due to the complexity of hydrological processes and the limitations of individual methods. Process-based models, satellite-derived water balance approaches, and groundwater-level analyses capture different components and scales of recharge, and no single method can fully represent recharge dynamics. To address this, this study applies an integrated framework combining SWAT+ hydrological modelling, remotely sensed water balance components, and the Water Table Fluctuation (WTF) method in the Ourika watershed, originating in the High Atlas of Marrakech and draining into the Haouz plain (Morocco). The dominant land use types of the watershed are grasslands and bare lands. The inputs of the SWAT+ model were prepared using the SRTM 30m digital elevation model (DEM). The improved maps of land use land cover from (ESA CCI LC) products were used to test different scenarios and their impact on the water balance. The soil characteristics are determined from FAO soil maps and the Harmonized World Soil Database and hydraulic characteristics are determined using the SPAW model. Daily rainfall is measured at gauge stations, and the meteorological variables such as daily wind speed, relative humidity, solar radiation, and temperature are collected within the watershed. The model was calibrated using daily stream flow data using Sequential Uncertainty Fitting (SUFI-2), which is one of the programs incorporated into R-SWAT interface. The annual recharge, calculated through the physically-based SWAT+ model, was compared to the estimated one using a remote sensing-based water balance approach. For this latter one, the water balance elements were calculated using satellite-derived datasets from GPM (precipitation), SEBAL (actual evapotranspiration), SMAP (soil moisture storage change), and NRCS-CN (runoff). This method provides spatially distributed estimates of recharge and enables direct comparison with SWAT+ outputs. In addition, the Water Table Fluctuation (WTF) method derived from piezometric time series was used as an independent field-based evaluation of recharge dynamics. The integration of both modeling and remote sensing approaches enhances the understanding of recharge dynamics in semi-arid environments and supports the development of sustainable groundwater management strategies in the Ourika watershed.