Measurement and characteristics of mountain stream wash loads in the Rokko Mountains

Keiji TAMURA, Yasukazu KOSUGE, Taro UCHIDA, Yoko NAGATA, Ken’ichirou KOSUGI, Takahisa MIZUYAMA

Abstract

pressed as a relationship between the product of the average gradient in the basin, D, and the area of the basin, A. It is expected that the relationship will depend on the geology of every region. 2) The current mechanisms for the generation and loss of wash loads in the mountain streams of the Rokko Mountains are thought to be based on the discharge of wash load components in riverbed sediment when stream water rises and the capture of these components when the water recedes. 3) When the environments that generate sediment in the basins change and the bare land ratio ra increases, α changes by orders of magnitude. 4) When slope failure and sediment discharge occur, the bare land ratio ra increases. However, when a riverbed gravel wash load capture mechanism is held, α does not increase. Conversely, it is predicted that when the wash load floating capture mechanisms are saturated, α increases.

Key words

mountain stream, wash load, turbidity, riverbed sediment, Rokko Mountains