The estuary ecosystem’s health and ecological integrity are essential for preserving environmental quality, habitats, and economic activity. The main objective of the present study is to comprehend the wave hydrodynamic impact on the Oued Sebou estuary, which is situated in the Kenitra region on Morocco’s north Atlantic coast in North Africa. Specifically, it focused on the dredging effect (caused by sand extraction) on the wave motion and its impact on the estuary environment. Different scenarios of wave-propagation simulations were carried out, varying the significant wave height, in deep water (from 1.5 to 4 m), and considering the bathymetry before and after two dredging cases of 2- and 4-m depths. The change of wave height at the Oued Sebou estuary shoreline was simulated by using the third version of the Simulating Waves Nearshore Model (SWAN). The SWAN model formulates the wave evolution in terms of a spectral energy balance on a structured grid. The effect of dredging on the wave spreading in addition to the flow hydrodynamic structures were extensively analyzed. According to the simulated results, the dredging activities in the Oued Sebou estuary mainly affect the river mouth and the southern breakwater area, increasing the potential erosive action. The areas at the northern coastal strip and near the northern breakwater are subject to possible accumulation of sediments.

Résumé :La nappe de Rhis Nekor est considérée comme la plus importante nappe alluviale de la zone méditerranéenne. Néanmoins, elle est confrontée à des pressions naturelles et anthropiques majeures, notons l'aridité de la région, le développement de l'activité agricole, la vulnérabilité à l'intrusion marine ainsi que son faciès chloruré-sodique et/ou potassique à sulfaté-sodique ce qui constitue un enjeu majeur pour ses ressources en eau. Le recours à la modélisation hydrogéologique a servi d'outil d'aide à la décision. Le modèle issu de cette étude a permis de simuler le comportement hydrodynamique de la nappe durant une période allant de 1972 à 2007. Les premières années de simulation montre une forte dépendance de la nappe aux sollicitations due à la mise en place du barrage Mohammed Ben Abdelkarim El Khattabi. A partir de cette date, les fluctuations piézométriques de la nappe sont fortement dépendantes au régime des précipitations et aux autres sources d'apport. Les scénarios établis ont permis de faire des simulations futures (jusqu'à 2027) traduisant les sollicitations diverses auxquelles la nappe pourrait être confrontées, d'où une éventuelle intrusion marine qui se met en place.

Oil spills are one of the most hazardous pollutants in marine environments with potentially devastating impacts on ecosystems, human health, and socio-economic sectors. Therefore, it is of the utmost importance to establish a prompt and efficient system for forecasting and monitoring such spills, in order to minimize their impacts. The present work focuses on the numerical simulation of the drift and spread of oil slicks in marine environments. The specific area of interest is the Azemmour estuary, located on Morocco’s Atlantic Coast. According to the environmental sensitivity index (ESI), given its geographical location at the intersection of the World’s Shipping Lines of oil transport, this area, as with many other sites in Morocco, has been classified as a high-risk area for oil spill accidents. By taking into account a range of factors, including the ocean currents, the weather conditions, and the oil properties, detailed numerical simulations were conducted, using the hydrodynamic TELEMAC-2D model, to predict the behavior and spread of an oil spill event in the aforementioned coastal region. The simulation results help to understand the spatial–temporal evolution of the spilled oil, the effect of wind on the spreading process, as well as the coastal areas that are most likely to be affected in the event of an oil spill accident. The simulations were performed with and without wind effects. The results showed that three days after the oil spill only 31% of the spilled oil remained on the sea surface. The wind was found to be the main factor responsible for oil drifting offshore. The results indicated that rapid action is needed to address the oil spill before it causes significant environmental damage and makes the oil cleanup process more challenging and expensive. The results of the present study are highly valuable for the management and prevention of environmental disasters in the Azemmour estuary area. The findings can be used to assess the efficacy of various response strategies, such as containment and cleanup measures, and to develop more effective emergency response plans.

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