Influence on deposition in Three Gorges reservoir caused by regulation optimization of flood-controlled water level

Regulation optimization of flood-controlled water level for the Three Gorges reservoir can improve much the overall benefit,but it may also cause an increase in sediment deposition and an unfavorable change in navigation conditions.This paper studies these influences with a one-dimensional sediment mathematical model and a two-dimensional sediment mathematical model.This study shows that the reservoir deposition will develop faster,while the difference in deposition rate under the influences is little during the first 100 years of reservoir operation.In different river reaches simulated,the influences on deposition volume are different,in absolute quantity the volume changes in the downstream reaches are the greatest,and in relative quantity the change in the region downstream to the backwater zone is the greatest.In the backwater zone,the influence on navigation downstream to Tongluoxia is little,and even upstream to this station,the influence is actually not significant because of the strong erosion effect caused by impoundment of the reservoirs upstream and by an decrease in sediment inflow.