CHARACTERISTICS OF GRAIN SIZE DISTRIBUTION OF RIVERBED AND THEIR DETERMINING FACTORS

2016 Fiscal Year Final Research Report

• Project/Area Number: 26870153
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Geography; Hydraulic engineering
• Research Institution: The University of Tokyo
• Principal Investigator: Chibana Takeyoshi 東京大学, 大学院工学系研究科(工学部), 准教授 (10372400)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 日本列島の地域区分 / 粒度分布 / 代表粒径 / 平均年最大流量 / 河床材料の移動頻度 / 空隙率

Outline of Final Research Achievements

By observing all class A rivers in Japan, Japan island is divided into 18 regions. We selected target sites from Segment M, 1 and 2-2 of several regions and examine the relationship between representative diameter and Shields number under the mean annual maximum discharge. Consequently, it was clarified that the size distribution and the movement frequency of riverbed material depend on the geomorphological condition of each region. Representative diameter in Segment M and 2-2 is quite different, but the shape of size distribution is quite similar when relatively coarse material is contained. We found that the distribution pattern makes porosity as small as possible.On the other side, the size distribution in Segment 1 is relatively uniform and the frequency of movement is relatively low.

Free Research Field

河川工学