Abstract: This research is to verify the difference of scour pit pattern on downstream movable-bed between model test and prototype, and to investigate the evolution of scouring in the downstream. With scattered granules to simulate the scoured bedrock, we chose three typical working conditions to re-play the scour in downstream of flood discharge section of the Three Gorges dam since impoundment. We found that the simulated scour topography was consistent with that of prototype measured under typical operating conditions at different stages, which demonstrated that the evolution of scour pattern is related with the geological characteristics of bedrock. Moreover, upstream water elevation, discharge, and scour time largely affect the scour pattern in downstream of the dam. 

Key words: Three Gorges dam, flood discharge section, downstream movable-bed, scattered granules, scour, topography