STUDY ON PREVENTING DOWNSTREAM MOVEMENT OF BARS IN MEANDERING ROCK-BED RIVERS

Abstract

For preserving a comfortable river ecosystem, it is important to restore the riffle and pools within engineered channels, where should play a role in the habitat diversity. It will be no easy task to restore the pool-riffle and bars in flat rock-bed river which is lightly covered with gravels, as contrasted with in the gravel river. Kinoshita and Miwa (1974) proposed the condition for preventing downstream movement of bars in meandering gravel rivers. This work is intended to apply this condition to meandering rock-bed rivers. By depositing sand and gravel in meandering section, it will be assumed to generate some bars in spite of rock-bed rivers. We investigate the validity of the Kinoshita and Miwa’s condition by experimental and numerical survey in mobile-bed and fixed-bed channel. For mobile-bed, we reconfirmed that the Kinoshita and Miwa’s condition is valid. For rock-bed, we derive the condition of deposition of sand in meandering section by relating with the ratio of meander length to channel width and the angle of meander.