Study On Sediment Depositon In A Channel-type Reservoir Using A Sediment Transpot Model

The sediment deposition of Channel-type reservoir combines both characteristics of river and lake,due to Channel-type reservoir's characteristics of both river and lake.Altash reservoir is taken as a case to study the sendimentation of the Channel-type reservoir.Altash hydro project is a large(1)scale conservancy project according to Chinese criteria for the classification of reservoir,which is a comprehensive utilization project of flood control,irrigation,power generation and other functions.The main function is the flood control and irrigation,taking into account the comprehensive utilization of power generation.Altash reservoir is the key project of Yarkand River Basin in planning.Reservoir storage quantity of suspended sediment averaged over many years is 29.93 million t by mass,and 23.02 million m3 by volume,storage quantity of bed load sediment averaged over many years is 3.85 million t by mass and 1.72 million m3 by volume.Annual sediment runoff(V/WS)is 86.06.According to the national standard,the design reference period is less than 100 years of damming building structure.Sedimentation problem of Altash resevior is very serious.This paper use the simulation method to study the sedimentation characteristics of Altash reservoir.The HEC-RAS model was established and verified by the experimental results of a physical model.The sediment deposition pattern and the amount of sediment deposition were calculated.Altash reservoir sedimentation pattern is delta deposition morphology.By comparing the sediment deposition under different operation regulations,the results shows that the amount of sediment depositon is less under the second operation regulation,and the resevior can retain larger storage capacity.This research is of certain guiding significance for determining the operating mode for Altash reservoir.This paper also stdudies the sediment deposition by changing the water level on the basis of the second operation regulation.The results show that the sediment deposition process is almost the same as the change of the water level in the flood period,but the difference of deposition amount is relatively large.When the water level of the flood period is lower,the total amount of the deposit is smaller,and the total amount of sediment deposition is relatively larger in contrast,and the operation mode of the reservoir has a certain reference value.