Assessing the eutrophication risk of the Danjiangkou Reservoir based on the EFDC model

As the source reservoir of the middle route of China's South-to-North Water Diversion Project, the Danjiangkou Reservoir suffers from eutrophication threatens. Thus, it is necessary to develop an eutrophication model for local water resource management. In this study, a three-dimensional (3-D) eutrophication model for the Danjiangkou Reservoir was constructed. The model is different from the existing models for its embedded sediment diagenesis model with fine grids, and it was calibrated and verified by DO, NH4-N, TN,TP and Chl a. The calibrated model was applied to 9 scenarios regarding the variations of a number of key factors, such as water diversions, the increases in TN and the decreases in inflows. The spatial-temporal patterns of trophic status were analyzed and the potential areas of algae bloom were identified. The results will be helpful for local water quality management and provide a valuable example for other similar research.