Scale Modeling of Wooden Debris Accumulation at a Debris Rack

Abstract

To prevent damages due to transported wooden debris during a flood, the debris is often retained in defined zones upstream of populated areas using a debris rack. Because thorough numerical modeling of the debris accumulation process is still challenging given the randomness of debris accumulation and the interaction between sediment and wooden debris, one main tool to study debris retention structures involves small-scale modeling. The main purpose of this experimental study is to analyze various aspects regarding the modeling of wooden debris and to provide information on reducing the laboratory effort. The focus is on the various factors influencing the accumulation process and the backwater rise and whether or not it is important to model them properly in small scale. The results indicate a significant effect of the approach-flow Froude number on the debris accumulation process, whereas the debris properties have only a minor effect on the resulting backwater rise so that effects of debris mixture are negligible.