Author(s): Muhammad Farid Maricar; Muhammad Islamy Rusyda; Haruyuki Hashimoto; Hiroyuki Nagano

Linked Author(s): Muhammad Islamy Rusyda

Keywords: Flood; Woody debris; Driftwood; Woody debris accumulation; Woody debris jam; Loss coefficient

Abstract: Log accumulation at a few bridges without a pier along the Nayoshi River in Tsuwano Town, Japan was produced during the 2013 flood event. The purpose of the present study is to investigate the characteristics of log accumulation at a model bridge in laboratory flume experiments. A model bridge without a pier was used in the experiments. The experiments showed that releasing log pieces into the flow generated log accumulation and backwater rise at the model bridge. The number of accumulated log pieces increased with the number and length of released pieces, although the data were scattered. The condition of log accumulation at the model bridge without a pier was examined. Simultaneous contact of a flowing log piece with the bridge deck and the flume bed is found important for the initial log accumulation at the model bridge without a pier. The backwater rise became higher with the number of log pieces accumulated at the model bridge. Head loss due to obstructions in river can be expressed by ‘loss coefficients’. The concept of loss coefficient due to the log accumulation was introduced for the discussion of the backwater rise. It is found that the loss coefficients became larger with volume of accumulated log pieces.

DOI:

Year: 2018