Author(s): Jingqiao Mao; Peipei Zhang; Lingquan Dai; Huichao Dai
Linked Author(s): Jingqiao Mao
Keywords: Optimal operation; Multi-reservoir system; Environmental water demand; Dongting Lake
Abstract: River-connected lakes play important roles in flood control, drought mitigation, water quality maintenance, and biodiversity conservation of watersheds. However, their ecosystems’functioning and stability might be sensitive to the altered flow regimes due to dam construction and flow regulation. Dongting Lake of China is a large shallow lake directly connected to Yangtze River in the middle region, of which its ecosystem functions have been threatened and disturbed by the upstream water resource development. In the study, an optimization model that considers both the basic human needs and environmental water demand (EWD) of Dongting Lake is developed for the operations of a multi-reservoir system. The system covers the world’s largest water resource project (Three Gorges Reservoir built on the upper Yangtze River) and two large reservoirs situated on the tributaries of Dongting Lake. The optimal target in pursuit of the ecological objective is to maximize the EWD satisfaction of Dongting Lake, which has been estimated from the analysis of long-term hydrological data. We use a support vector machine-based model to examine the response of lacustrine hydrological conditions to reservoir operation and inflow of other tributaries. The optimization is carried out for different scenarios, and the results show that: (i) the existing operation policy have been resulted in significant hydrologic alteration in the natural flow regime; (ii) an optimal joint operation policy proposed in the study could increase the general EWD satisfaction rate of Dongting Lake from 89. 4%to 96. 9%; (iii) the overall degree of lake’s EWD satisfaction is mainly affected by the operation of Three Gorges Reservoir.
Year: 2015