The Effects of Urban Development on Sedimentation

Abstract

Channels are the main conduit for floodwater conveyance in a watershed. The channel geometry can change due to a high peak discharge, which causes erosion and subsequent deposition that can change the downstream channel geometry. Urban development can lead to increases in peak discharge, and therefore, channel erosion and flood hazard. The purpose of this research is to assess the effect that urban development has on erosion and downstream deposition. A hydrologic model was built to simulate the effect urban development has on erosion volumes and depths of downstream deposition at the watershed outlet. The results indicated that the amount of erosion and deposition exhibit a non-linear relationship with the level of urban development. Therefore, developing watersheds should plan for a non-linear increase in flood hazard. The model developed can be applied to any watershed with knowledge of some basic regional and local characteristics. Guidelines for the model application were also developed.