Abstract
A huge deep pool called ’Bentenbuchi’ existed in the Yadagawa river which flows the northern part of Hyogo prefecture until the 1970s. However, the Bentenbuchi pool is filled with sediment and has disappeared as of 2013. In this study, the cause of disappearance of the Bentenbuchi pool and the mechanism of the disappearance were examined. First, from the comparisons of the aerial photographs from the 1970s, it was shown that the Bentenbuchi pool has disappeared after the installation of the Ono weir in the 1980s. Then, 2-dimensional riverbed variation analysis with consideration to the existence or nonexistence of the weir was performed. From the results of analysis, it was specified that the installation of the Ono weir is the cause of disappearance of the pool, and the mechanism was also clarified.
