超過洪水による中小河川の河道災害

Abstract

From a viewpoint that river improvement works shoud be effective even underexcess flood conditions, river channel damage caused by 1988 flood was studied in afew small to middle sized rivers in the western part of Shimane Prefecture, as anexample, in order to evaluate functions of river improvement works for damagereduction. Fundamental experiments were carried out to clarify failure mechanismsof revetment, which is the commonest works for river improvement, due to excessfloods. Failere patterns of revetment in the experiments were very similar to thoseproduced by overbank flow in small-middle sized rivers. Channel bed variationwere surveyed in curved reaches where large amount of sediment deposit and severedamage of revetment were observed. Transevers sloes of inner bank deposit couldnot be predicted by several equations of previous investigators.