Optimization of water quality evaluation method in Three Gorges Reservoir area under different hydrological conditions

Abstract

Abstract. In order to solve the problem of lack of unified evaluation criteria for water quality evaluation in the Three Gorges Reservoir under different hydrologic condition, hydraulic retention time and flow rate were calculated wih the hydrological data of 6 intact hydrological years after the 175 m impoundment in the Three Gorges Reservoir using the concept of segment capacity. Results indicate that the hydrological conditions of the Three Gorges Reservoir have obvious spatial and temporal differences. The whole river should be evaluated according to the river standard during the wet season. In the dry season, the upstream of Wanxian should be evaluated according to the river standards and the downstream of Wanxian should be evaluated according to lake standard. The tributary bay should be evaluated according to the lake standard. The conclusion obtained by this evaluation method is consistent with actual situation of the reservoir, providing a theoretical basis and technical support for the targeted protection of water environment in river-type reservoirs.