Predictions of bulk velocity for open channel flow through submerged vegetation

Vegetation is of great significance in river ecosystems in terms of hydrodynamics, water environment and ecology. The question of how to predict the bulk velocity in channel flow through submerged vegetation is currently a hot topic in hydraulics research. The present study addresses this question. The various formulae used for bulk velocity estimation in previous work were reviewed and compared. The main novelty of this paper is that a new expression of friction factor is proposed as a function of two dimensionless factors, and the number of tuning parameters is less than that in previous work. A comparison of measured and calculated data was conducted for flow through submerged rigid and flexible vegetation. The comparison showed that the proposed new model can make more accurate predictions than previous models. It is envisaged that the proposed formulation can be usefully employed in eco-hydraulics predictions.