植被指数の定量解析による砂州の植生域変動の予測

抄録

The vegetation on a sand bar is strongly dependent on secure flood control and conservation of the river environment, which are therefore extremely important in watershed management. In this paper, the change of vegetation on the sand bars was examined on the Kita River, Miyazaki Prefecture, Japan. Firstly, a new function was proposed to describe the relation between the dimensionless tractive force and the vegetation index which expressed the vegetation coverage and abundance of vegetation on the sand bars. This function was applied to qualitatively analyze the change of vegetation on the sand bars. The simulated results clarified the history of vegetation destruction and restoration on three sand bars of the Kita River over the past 41 years. Secondly, the function was applied to predict the change of vegetation after ten years on two sand bars excavated in the river improvement work in 1999. The predicted results indicated that the change of future vegetation deeply depended on the maintenance of excavated ground surface elevation of the sand bars.