Author(s): K. Yoshida; S. Maeno; S. Fujita; S. Matsuyama
Linked Author(s): Keisuke Yoshida
Keywords: Vegetation management; Vegetation dynamics model; Field observations; Prediction of the vegetation condition
Abstract: Forestation in rivers has recently been of concern in Japan. It generally reduces river flow capacity, damages lower reaches with driftwood, and changes ecosystems. As one countermeasure against forestation, maintenance work is carried out continuously in Japan, cutting down growth on sandbars in rivers. However, sandbars often become covered with vegetation after several years. Therefore, it is necessary to elucidate vegetation dynamics in rivers to facilitate their effective management. This paper describes a model of vegetation dynamics and its application to the Ohara area in the lower Asahi River in Japan. We verified its reproducibility based on field observations. Then we predicted aspects of the forestation process in the river for the decade beginning in 2013. Results for validation calculations showed that our model can fundamentally reproduce vegetation conditions in this area. The predicted results demonstrated that the vegetation established more thickly and that the vegetation height is expected to become 12 m in the area in 2022. Vegetation less than 5 m tall will be washed out. Vegetation more than 10.5 m tall exhibited little impact by floods of 3400 m3/s if no vegetation exists in the upper area of Ohara area.
Year: 2014