Predicting Influence of Bank Vegetation on Channel Capacity

Abstract

A theoretically based method for taking into account the effects of bank vegetation on channel-flow parameters is outlined. It can be used to predict what effect changes in bank vegetation will have on the discharge capacity of a channel and to make comparisons of bank-vegetation effects between channels. Using the analysis on individual channels may aid in gauging the true impact of bank vegetation on in-bank flow capacity and in deciding whether the beneficial effects of bank vegetation in stabilizing banks outweigh any adverse effects that result from the potential reduction in discharge capacity. Using this method, the effect bank vegetation has on channel discharge capacity is shown to decline rapidly as the width-to-depth ratio of channels increases. When seasonal growth of vegetation is simulated the effect on channel discharge capacity is shown to be less than 10% for channels with a width-to-depth ratio greater than 16.