Pacific Bay Power Plant Tailrace Channel Dredging Program Of Study

After the flood discharges in 1995, parts of downstream channel is silted up in TaiPing Wai PowerStation. It raises the water lever, and decreases the work of generating unit. In order to increase generating electricity benefit, the powerstation would like to excavate downstream channel. To choice good excavating scheme, this article engages in hydraulic model tests and numerical simulation on the movable bed.Based on the study before, dimensional analysis is used to get similar rule of the silt movement. Limitations of the similar relations based on the experience formulas of silt movement directly is overcomed. According to the similar rule, a movable bed model for downstream channel and the particle size distribution of the model silt in the channel and the scour hole are designed. A theoretical method of size distribution in the scour hole is devised. The results of the model tests both in scour and deposit are basically similar with the prototype, and the movable bed tests of some good excavating schemes have been finished.This article also finishes numerical simulation of one dimension on the movable bed. The results of physical model and numerical simulation are agreement roughly. The scale effects due to unsimilar bed risistance is discussed in detail, and the correct way of scour depth is supposed.At Last, a new transport rate formulas of uniform or nonuniform bed load is given.