Author(s): Takahisa Shinjo; Yuuichirou Fujita; Jun-Ichiro Takahama
Linked Author(s):
Keywords: Sedimentation; Sediment concentration; Accumulation curve of sediment volume
Abstract: Sakuma dam reservoir constructed in 1957 for power generation has reduced its initial total storage capacity of 327 Mm3 to 213 Mm3 in 2002 due to the largesse sedimentation volume of 114 Mm3 in Japan, which may cause inundation in the upstream area raising by riverbed there. In order to mitigate this flood damage, a few countermeasures are being attempted to degrade the riverbed such as dredging removal and flushing by running water with lowering the storage level, the latter of which is called artificial activation of sediment transport. The riverbed has, however, not been degraded sufficiently, hence accumulated reservoir data of flow discharge, cross sectional surveying and grain size distribution were examined to clarify actual state of the sedimentation and efficiency of flushing by river flows with lowering of the storage levels, namely “artificial acceleration of sediment transport”. The results show that a technique using accumulation curves of volumetric changes of cross sections for individual grain sizes can express well the actual states of annual sediment movement. in the reservoir
Year: 2005