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Abstract Over the time it has become a challenge to protect Mariout Lake from pollution and violations. As it is of a great economic and environmental value, the only outflow water source for the lake and all its inflows is Al Max pump station, which raises the water from the Al Omoum Drain to the Mediterranean Sea. By observing the way the station is managed and the geographic nature of the area, it is noted the disappearance of the embankments between Al Omoum drain and Al Max pump station as a result of the fishermen’s cutting the banks of the basins dividing the lake to freely move between the lake basins, which led to the withdrawal of large quantities of water from inside the Lake to the Mediterranean sea by the pump station without considering the allowable discharges that can be pumped to the sea and not affecting the lake. On the other hand, the withdrawal of large amounts of water without calculating the actual daily discharges resulted in the addition of great pressure on Al Max station. The station is designed to operate on certain discharges, which are the discharges of the agricultural drains in the regions of Alexandria and Al Behira collected in Al Omoum drain. As a result of the continuous pressure on the station, a reduction in its efficiency caused the pumps to be prone to stop, putting the entire area at risk of drowning. A hydrodynamic numerical model is used to study the current status of the Mariout Lake. The lake basins are subjected to the discharges coming from the agricultural drains and the point sources discharging directly to the Lake. Simulation of the flow circulation inside the main basins of Mariout Lake is done using Delft3D hydrodynamic model which is calibrated and validated knowing values of the water depths in different locations across the basins. The results of these simulations show a good match between the simulated and observed data for water velocities. Once the ability of the model to simulate the hydrodynamics of the lake is testified, the model is being used to simulate water depth, exchanged flows and velocities. Many scenarios were made to enhance flow in the lake and to determine the optimum solution to separate Al Max pump station from the lake. Results show the need for the composition of embankments between Mariout Lake and Al Omoum drain, while constructing number of feeding vents at chosen locations. By this, it will be ensured that Mariout Lake will not be exposed to drought at summer times, and that Al Omoum drain and El Max pump station will not be in danger of drowning due to pumping out excess water from Mariout Lake during heavy rainstorms. The study recommends also the construction of bridges on the desert road to allow water to pass between the basins freely. In addition, the dredging of the bed of the lake t will significantly help in raising the water level in the basin thereby increasing the self-purification rate in the lake and allowing the lake to accommodate more discharges. |