Manzala lake is a model example of shallow water bodies exposed to huge amounts of drainage water containing organic and inorganic pollutants, which can be thrown in it directly or indirectly. This research aims to assess the water quality condition of Manzala Lake using the method of water quality index. The existing situation of the lake water quality is evaluated and used as a baseline for comparison with the lake water quality condition under different modeled scenarios of enhancement. To calculate the lake indices, a 3-D hydrodynamic numerical model is developed, coupled to a water quality module for the lake using the Delft-3D modeling system. The weighted arithmetic mean method is used to calculate the water quality index of the lake. The results of the model simulation imply that the improvement in the water quality of the lake is directly proportional to the increase of sea lake interaction and the reduction of the polluted effluents from drains. The optimum water quality index is achieved by reducing the water level in the lake via decreasing the effluents from the Bahr Al-Baqar drain and enhancing the density current from seawater to the lake by increasing water depth inside the lake by dredging the total area of the lake. All obstacles due to human interaction inside the lake must be removed in addition to constructing a new inlet through the Mediterranean Sea. It is concluded also that the lake is on the threshold warning of heavy metals according to the metal index method. |
