Sand deposition after flood to cause troubles around barrages, whose sill elevation is lower than that of former river bed, 1: Analysis of sand deposition process during a flood stage
1991
Miwa, H. (Iwate Univ., Morioka (Japan). Faculty of Agriculture)
The barrages have been built to follow the new design standards authorized by the Ministry of Construction in these 10 years. Some of them have had troubles caused by deposition of sand and gravel on the sill of barrages after big flood. These kinds of cases are studied to analyze; 1) field observation, 2) surveying maps, 3) aerial photographs, and 4) experiments in a hydraulic laboratory. This study revealed such conclusions as follows: 1) The new design standards enforced engineers to design and construct barrages with their sill elevation equal to that of "planned" river bed, which is lower than former one. 2) Dredged and mined reach of river bed around a barrage is usually the length of channel width respectively in upstream and downstream direction. 3) But dredged area mentioned above is not so sufficient that sand and gravel accumulate on the sill of the barrage during big flood
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