Study on water-sediment variation in Poyang Lake Basin and simulation of water-sediment out of Lake
Since the 1950s,the climate of Poyang Lake Basin has changed,human activities have become increasingly frequent,precipitation,runoff capacity and sediment yield capacity have changed significantly.Based on the data of the control stations for"five rivers"entering the lake and the Hukou hydrological station in the lake controlling water and sediment out of the lake,the Mann-Kendall test method and the double cumulative curve method were used to determine the time point of the annual sediment load mutation,and then the cumulative slope variation analysis method was used to quantify the influence of precipitation,runoff yield capacity and sediment yield capacity on the sediment load of Poyang Lake.On this basis,a multi-method coupling water and sediment simulation model based on variational mode decomposition,LSTM neural network and complete stepwise sampling technique and its evaluation method were proposed,and a specific water-sediment simulation model for the Hukou Station was established.The results show that the climate change factors represented by precipitation change have little effect on the change of sediment discharge into the lake or the change of sediment deposition in the lake area.The main influence is from the human ac-tivity factors.However,the specific influences from human activity are diverse.The contribution rate of human activities to the a-mount of sediment entering the lake is on the rise,but the contribution rate to the amount of sediment deposited in the Poyang Lake area during the same period shows a firstly decreasing then increasing trend.The water-sediment simulation analysis shows that the simulation process of monthly runoff and sediment discharge at Hukou Station was in good agreement with the measured process,and high simulation accuracy was obtained.The water levels of Hukou and Xingzi Stations have little contribution to the improvement of simulation accuracy.
water-sediment variationwater-sediment simulationattributional analysisPoyang Lake
万方数据
维普
