Author(s): Muto Yasunori; Sumida Hideyuki; Tamura Takao
Linked Author(s): Yasunori Muto
Keywords: Bed evolution; Experiment; Falling works; Sand bar; Dam removal
Abstract: There often exists a conflict between flood alleviation and environmental preservation in river management. One of the important issues is how to design and construct river-crossing structures such as dams, weirs and falling works. Some attempts in order to restore and/or compensate discontinuity of the river by the structure have been adopted, however its effect on river bed morphology is not well explored yet. In this study a series of laboratory experiments were conducted to study effects of falling works improvement by partial removals on evolution and instability of the bed. For the upstream reach how a sand bar configuration is changed according to modifying the position of the falling works removal is of particular interest. For the downstream reach, in addition, how change of sediment supply from the upstream by the removal will affect the local scour and bed configuration is studied. The results clearly show that the position of the removal strongly influences both the sand bar formation in the upstream and the shape of scour hole in the downstream. This indicates that, although special care is necessary from the viewpoint of channel stability, the partial removal can contribute the river regime being restored to its natural condition.
Year: 2013