The effect of instream logs on bank erosion potential: a flume study with multiple logs

Abstract

Riparian trees can reduce bank erosion rates, but once a tree falls into a river it can increase local bank erosion. However, the influence of multiple logs, that hydraulically interact, on near-bank velocities has not been investigated. This paper reports flume experiments of the near-bank velocity changes and water level changes produced by multiple in-stream logs with equal and unequal spacing. The results suggest that the near-bank velocity increase caused by a single log can be reduced, and even reversed, by multiple logs. This reduced near-bank velocity mainly results from wake interference between the logs, rather than from the effect of backwater, and it varies systematically with th..