Research on the Middle and Lower Reaches of the Yangtze River and Lake’s Hydrological Alterations Based on RVA

Abstract

On the basis of river-lake relationship analysis, this paper chose the middle and lower reaches of Yangtze River where the Poyang Lake locates as the study area. The storage variable of Three Gorges Project was deduced to hydrological stations at the lower reaches. The natural runoff processes of hydrological stations were restored. Then RVA method was applied to analyze the hydrologic alterations of river channels at the hydrological stations before and after reservoir operation. The analysis result indicated that Hankou hydrological station and Datong hydrological station at the lower reaches had medium changes after operation of the Three Gorges Project. The hydrological regimes of Hankou hydrological station, Hukou hydrological station and Datong hydrological station in different periods before and after operation of Three Gorges Project were analyzed, the water exchange between Poyang Lake and the middle and lower reaches of Yangtze River was investigated, and the relevant results indicated that the inflow of lower reaches river channel decreased during impoundment of Three Gorges Project, the water level of river channel dropped, and the outflow from the lake increased, which was the major reason behind water deficiency of Poyang Lake area. The recommendation is to optimize the Three Gorges Project’s water storage scheme, so as to improve the river-lake relationship at the middle and lower reaches of Yangtze River.