Abstract: Vegetation is an important feature of natural rivers.Based on the flume experiments with aluminum cylinders simulating rigid vegetation and the laser Doppler velocimetry,the influences of vegetation submergence and density on the velocity distribution are investigated in this study.The analyses indicate that the mean streamwise velocity can be expressed by a function of flow discharge,channel width,water depth and vegetation density for non-submerged vegetated flows.For submerged cases,it is difficult to fi...