Paper (In Japanese)
A STUDY ON THE NATURE OF SEDIMENT RUNOFF IN ZERO-ORDER BASINS AT STEEP SLOPE AND EXTRACTING METHOD OF DANGEROUS BASINS
2022 Volume 78 Issue 4 Pages 306-320
Details
2022 Volume 78 Issue 4 Pages 306-320
Sediment runoff at steep slopes is one of the serious problems about sediment disasters caused by heavy rains. Establishing proper methods for its risk assessment has today become an urgent issue to combat the problem. This study, by conducting a field survey and topographic reading in three locations affected by Heavy Rain in July 2018 and with different foundation geology, investigates how different topographic characters and different foundation geology of zero-order basins are related to sediment runoff from them. As a result, we find that sediment runoff from zero-order basins is closely related to the development of basins. It tends to occur at zero-order basins which have a loose sediment layer with less than 20 Nd and more than 1.1m depth. We observe no correlation between sediment runoff and foundation geology or ground material. Zero-order basins with a high risk of sediment runoff can be extracted by topographically monitoring the total valley length and the maximum b/a which increases with the development of valleys.
