الفهرس 
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Abstract
Lake Manzala is the largest Egyptian coastal lake and is considered the most valuable fish sources in Egypt. Water quality status of the lake has been degraded in the last decades due to the progressive increasing of industrial, municipal and agricultural wastewater discharges from six main drains are; Bahr El-Baqar, Hadous, Elserw, Mataria, Fareskour and Ramsis. The Lake recives about 5.5 BCM per year from polluted drain water in spite of the Lake has only two effective outlets to the sea and one to the Suez Canal. Lake water, fish and sediments are contaminated with heavy metals (Mn, Cd, Zn, Pb and Cu) and with high amount of (TVB) and (FCB). The main objectives of this work are; to produce a total water quality management plane for Lake Manzala, to develop a (HD), (AD) and (ECO Lab) model for Lake, under data scarcity, using MIKE21 modelling system and then using the calibrated model to assess water quality status and eutrophication level of Lake Manzala by conducting the TRIX index, to test ten water quality management scenarios and to study and evaluate the impact of two new projects under construction on Lake Manzala. The first is to divert Bahr El-Baqar drain to Sainai then treating drain water and using the treated water in land reclamation, while the second is to dredge basins in front of the main lake outlets to the sea (El-Gamil 1 and 2) at level (-2.50) and dredging the outlets itself and a three kilometres channels from the outlet to inside the lake at level (-3.00) which is called Radial Channels Project. The simulated parameters are (water depth, temperature and salinity) and (BOD, DO, NO2, NH3, PO4, NO3, Chl-a and TP). The proposed model was calibrated with observed data for one year (August 2010 to August 2011) collected from five record stations for water levels and hydrodynamic and water quality data were collected from eleven field record stations at Lake Manzala. The model results showed good agreement with the observed data. The first group for water quality management scenarios is for Bahr El-Baqar drain (four scenarios) are for reduction drain inflows to lake by (50%, 75% and 100%, respectively) and treatment 50% from nutrients load (NO2, NO3, NH3, PO4 and TP) from drain water. The second group is for lake outlets, (four scenarios) where constructin radial channels for El-Gamil 1 and 2, the second and the third are adding new outlet to the sea (El-Gamil 3 and 4) in two different possitions while the fourth is adding new outlet (El-Gamil 3) with radial channels for three outlets (El- Gamil 1, 2 and 3). The last gruop is a combined between two groups, by reducing Bahr El-Baqar drain inflows by 75% and using radial channels while the second is the same but the inflow reduction is 100%. The results showed a significant improvement in Lake Manzala water quality status when reducing the drain inflows to the lake and small improvement in water treatment and radial channels while no improvement when adding new outlets because of the great pollution comes from drains. The diverting project of Bahr El-Baqar drain will enhance water quality status of Lake Manzala by about 55% for one year after finishing the project and nearly the whole lake turned to high water quality status and low eutrophication level in TRIX index, while Radial Channels Project will improve Lake Manzala water quality status by about 12% and enhance Lake water quality status and eutrophication Level.