Effect of plan layout on the sediment control efficiency of slit-check dams for stony type debris flows mitigation

Abstract

There has been an increasing acknowledgement of debris flows as one of the most relevant geomorphic modifiers of many steepland valleys and fans. Despite it being a well-known phenomenon, debris flows are somehow unpredictable and complex to simulate. Due to several past harmful debris flows worldwide, there are already a significant number of mitigation structures with water and sediment control functions, which are essential features of short-term countermeasures against debris flows. This paper is based on laboratory experiments carried out to test slit dams (open-type retention dams), usually used as a structural countermeasure to mitigate debris flows in steep torrential channels. Flume tests were conducted using a straight channel to assess the influence of different slit-dam solution types on the sediment retention efficiency against stony-type debris flows. Inspired by common slit dam solutions, two different piers layouts in plan view were tested. The experiments were performed with two different discharges and two different slopes. Experimental results about the sediment control efficiency are presented for the different tested solutions.