Abstract: As reservoir sedimentation is very serious in China, remarkable achievements have been made in the study of reservoir desilting, but few are about the desilting under small flow. In this article, hydraulic model test with movable bed was carried out and a scheme of desilting in the presence of guide wall was proposed. Guide wall is proved advantageous in desilting under small flow rate through analyzing the desilting effect in the presence of guide wall under different flow rates. Moreover, desilting tests in the presence and in the absence of guide wall under different flow rates suggest that water depth is influential in the scour effect, and the water depth should be less than 1m to achieve the optimal result. Under large flow rate, guide wall is not as effective as that in small flow rate; hence different measures should be taken in different conditions. This research provides a new idea for reservoir desilting both under small flow and comprehensive conditions.

Key words: reservoir sedimentation, model test, desilting with guide wall, velocity distribution, water surface profiles