A STUDY ON MANNING'S COEFFICIENT OF RIGID UNSUBMERGED VEGETATION UNDER OPEN CHANNEL CONSTANT GRADUAL FLOW CONDITION

摘要

A series of experiments were carried out to study the hydraulic resistance of rigid unsubmerged vegetation in open constant gradual channel flow. Flow depth and velocity were measured in the density of 54, 108 and 202 reed stems per square meter within a range of discharge values. The results demonstrated that the back-up water height increases with the reed density, while the velocities show an opposite trend. The phenomenon can be explained by the relationship between Manning coefficient and the vegetation density parameters.