中流域における平瀬の物理特性とその評価

抄録

To understand the dynamics of the bar’s structure and river bed materials is essential in order to protect and revitalize the river environment in the middle reach. Up to this date, there has been much research that focused on the structures and their potential as eco-habitats of gravel bars, riffles, and pools, but not runs. Generally runs are considered as a uniform environment, but some studies show that runs are rich environment for some species. This research focuses on runs’ structure and potential as eco-habitat.

As a first step, we have done field researches to clarify the relationship between runs and surrounding topography such as a pool or a sand-bank. Then numerical model that is called River2D was used to estimate the river flow in the flood condition. Based on the results of these analyses, the followings are clarified. Fine gravels tend to deposit in the inner bank, and the amount of the fine gravels is related to the types of gravel bars. Sands also tend to deposit in the inner banks, but the amout of sands in the runs are related to the types of pools and bank protection.