Effects of aquatic and bank-side vegetation on hydraulic performance of small streams

Abstract

We consider effects of bed and bank-side vegetation on hydraulic resistance of small streams, and develop simple quantitative relationships for predicting and quantifying these effects using the normalized plant characteristics. We conducted two field studies to explore effects of submerged aquatic and bank-side vegetation on stream hydraulics. In the first study, we examined the effects of aquatic plant biomass, stature and architecture on hydraulic conditions in five small streams representing a range of channel dimensions, flows and aquatic plant assemblages. In the second field study, we created experimental floods in a small stream to examine the effects of submerged bank-side vegetation on hydraulic conditions. The results of the studies and the relationships presented in the paper may be used to provide initial estimates of resistance coefficients for hydraulic modelling, predicting effects of aquatic weed management and bank-side planting on flood levels, and designing naturalisation and enhancement projects for small streams.