VERIFICATION OF FIELD RECOVERY TECHNIQUES AGAINST THE BED DEGRADATION IN THE ASA RIVER

Abstract

Shale-bed exposures caused by progressive riverbed degradation, seriously affect river safety and proper management in the Asa river. In order to recover riverbed level, the field experiments, that arranged big stones to capture transporting sands and gravels during flood, have been conducted for about six years since 2009. It was ascertained that riverbed level had been stable in the field experiment sections even after the 2015 flood that exceeded the average annual maximum discharge. Riverbed recovery technique using arranged big stones was verified to be valid.