Simulation of eutrophication in Shenzhen Reservoir based on EFDC model

Abstract

基于EFDC模型构建了深圳水库三维水动力和富营养化定量模拟模型.分别用2009年和2010 2011年流量、水位和水质等观测数据对模型进行了校正和验证,准确地反映了深圳水库的水动力和水质变化过程.在此基础上,假定支流污染截排、水库调度和降低东江引水污染负荷3种情景进行深圳水库富营养化数值模拟,3种情景下库中Chl.a峰值浓度分别降低1.0%、16.4%和46.3%,平均浓度分别降低1.3%、29.8%和29.9%.深圳水库具有良好的交换能力,尚未出现水华暴发,但入库营养盐负荷高,存在较大的富营养化风险;在目前沙湾河污水已经截排的基础上再实施支流污染控制,对水质改善和藻类控制作用已不明显;水库调度和削减东江引水污染负荷对深圳水库水质和富营养化改善明显,能够有效降低水华发生的风险.;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.