Hydrodynamic and Water Quality Modeling of Lake Mariout (Nile Delta, Northern Egypt)

Abstract

Egyptian coastal lakes, which represent about 25% of the Mediterranean total wetlands, are not only one of the most valuable ecosystems in the world but also some of the most threatened as they receive the wastewater discharged from the watershed. Lake Mariout was one of the most important shallow coastal lakes north of the Nile Delta of Egypt that produces between 50 and 70% of the total fish production of the coastal lakes, but it was widely used to drain industrial wastes, sewage, and agriculture drainage. As a consequence of the environmental degradation, it has changed from being the most productive fishery resource of the four major Egyptian brackish water lakes to the least productive in a couple of decades. Over the past few years, water quality and hydrodynamic modeling of lakes, lagoons, and rivers has become an important tool for managing water resources, especially in modeling the dispersion of pollutants. The objective of the study is to build a hydrodynamic and water quality model of Lake Mariout, to show the current status of the lake which is subject to pollution from the agricultural drains and the point sources discharging directly to the lake. That objective is achieved through simulating the flow circulation inside the main basin of the lake and the transport and advection of the pollutants and then identifies and develops the most critical surface drainage water quality indicators to simulate and predict the temporal and spatial variation of pollution. The model proved to be an effective tool for the water dynamics, water quality simulation, and evaluating different scenarios of such shallow lake.