DOWNSTREAM NEAR DAM RIVER BED PROTECTION STUDYFOR GEZHOUBA HYDRAULIC PROJECT

摘要

Since Gezhouba Hydraulic Project is builded, its downstream near dam middle-low water levelrnbegins to decline. After Three Gorges Project begins to store water, clear water discharging will result inrnnew scour-sediment changes in the river bed of two dams river section and downstream GezhoubarnHydraulic Project from above to end, in some period, water level of downstream Yichang station riverrnsection will decline further. When small discharge appears in Yangtze River and further water levelrndeclining in Yichang station will not make Sanjiang navigable depth fulfil design standard, the navigationrnsafety of ship locks in Gezhouba Hydraulic Project is threatened. Therefore, in the mean time ofrndischarging compensation flow from Three Gorges Project and increasing downstream navigable depth,rnbased on the river section’s scour rule, engineering methods should be carried out to prevent river bed ofrndownstream Gezhouba Hydraulic Project from scour, to prevent near dam water level from declining. Inrnthis article, based on sediment research data, prototype observation data and the river section's scour rule ,rnthe control river section which results in near dam water level decline is confirmed，full section bottomrnprotection is carried out in the river bed to find the effect of field test which prevent near dam water levelrnfrom declining in low water period. Prototype observation data indicates full section discontinuousrnbottom protection carried out in near dam river bed of downstream Gezhouba Hydraulic Project isrnadvantageous to prevent water level from declining.