Simulation of eutrophication in Shenzhen Reservoir based on EFDC model

The three-dimensional hydrodynamic and eutrophication model of Shenzhen Reservoir was developed based on EFDC framework. Model calibration and validation were conducted with two sets of independent observed data of water flows,water levels,and water quality in 2009 and 2010 2011. The model represented the hydrodynamic processes and the spatial and temporal distributions of water quality satisfactory. Subsequently,three scenarios were configured to provide decision makings for eutrophication control,included removing 100% nutrients from all tributaries,increasing by 50% of water flows,and removing 50% nutrients from Dongjiang. As shown by the modeling results,the maximum chlorophyll-a concentrations were decreased by 1. 0%, 16. 4% and 46. 3%,respectively,the average chlorophyll-a concentrations were decreased by 1. 3%,29. 8% and 29. 9%,respectively. Therefore,there is no water bloom in Shenzhen Reservoir so far because water has been exchanged quickly,although there has been eutrophication threats because of the large numbers of nutrients entering into the reservoir from Dongjiang. Increasing water flows and removing nutrients from Dongjiang can significantly improve water quality and effectively reduce the risk of water bloom in the reservoir.