Downstream frontal velocity reduction resulting from baffles

Abstract

Debris flows occur in mountainous regions during rainfall and can result in disastrous consequences to downstream facilities if appropriate mitigation measures are not taken. Common mitigation measures include flow impeding structures within the flow path. An array of baffles is a type of flow impeding structure used primarily to reduce the mobility of landslide debris. However, they are usually designed on an empirical and prescriptive basis and the degree of impedance resulting from an array of debris flow baffles is not well understood. This paper presents a series of systematic flume tests examining the influence of baffle row number on reduction of debris frontal velocity. Photoconductive sensors installed at the base of the flume channel have been used to measure the average frontal velocity of the debris flow downstream of the array of baffles. Results show that one row is ineffective in reducing the debris frontal velocity. Two to three rows of baffles exhibit notable frontal velocity reduction.