Estimating the depth of deposition (erosion) at slope transitions on alluvial fans

A typical flood mitigation structure on an alluvial fan consists of a dike/ channel system that deflects the flow away from the area requiring protecti on. Such a structure results in a change in channel slope from steep to mil d when the flow first encounters the structure and from mild to steep when the flow is released at the downstream end of the structure. These slope ch anges result in sediment deposition at the point where the flow encounters the structure and erosion at the point of release. In designing the structu re, the length and maximum depth of deposition (erosion) are critical varia bles that must be estimated. A simple model to estimate these variables is proposed and developed. The hypothesized model has been used to estimate th e length and depth of deposition (erosion) on several projects in southern Nevada.