NATURE FRIENDLY BANK PROTECTION WORl(S USING SANDBARS WITH BOULDERS IN THE JYOGANJI RIVER
2012 Volume 18 Pages 233-238
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2012 Volume 18 Pages 233-238
It has been observed in the Jyoganji river, which is one of the most rapid stony rivers in Japan, that bars in front of banks are eroded and washed away by concentrated flow along concrete revetments. To prevent bar erosions from floods, upstream side of bars were protected by boulders. The protection work has been found to contribute significantly to the stabilization ofriverbed and banks under flooding.
This paper shows the results of field experiments conducted to verify the effectiveness of the protection works under the different conditions in flow discharge (Q = 8 & 15 m3/s) as follows: (1) In the experiments for un-protected alternating bars, the erosion and washing away process reappeared as observed in the Jyoganji river. (2) It was confirmed that the protection works were effective even under the large discharge condition (Q = 15 m3/s).
