Data Analysis and Numerical Experiments of Riverbed Evolution in Lower Reach of Arase Dam

Abstract

Yusuke YOSHIMORI, Kazuaki OHTSUKI and Yasuo NIHEIA measure to reduce the environmental impacts of dams is a dam removal which has been conducted in Arase dam, Kuma River. However we have poorly understood influences of dam removal or construction on riverbed evolution in lower reach of dam. In this study, we attempted to clarify the response of riverbed evolution after dam removal or construction by data analysis for long-term monitored riverbed and 1D analysis for riverbed evolution under various sediment supply conditions. The numerical results indicated that the propagation process of riverbed evolution to the downstream direction seemed to be a kind of diffusion process. Using this results, we can simply evaluate the riverbed evolution in lower reach after completing removal of Arase dam.