Measuring the flow and Manning's roughness coefficient of mountain streams

• ASANO Yuko

  The University of Tokyo Forests, Graduate School of Agricultural and Life Sciences, The University of Tokyo

• HOSHINO Shinichiro

  Graduate School of Agricultural and Life Sciences, The University of Tokyo

• UCHIDA Taro

  Research Center for Disaster Risk Management, Erosion and Sediment Control Division, National Institute for Land and Infrastructure Management

• AKIYAMA Koichi

  Token C. E. E. Consultants. Co., Ltd.

Bibliographic Information

Other Title

• 山地河道における水の流れとマニングの粗度係数の実測
• サンチ カドウ ニ オケル ミズ ノ ナガレ ト マニング ノ ソド ケイスウ ノ ジッソク

Abstract

Improved flood prediction in mountainous catchments requires knowledge of the hydraulic characteristics of mountain streams. The flow and flow resistance of steep mountain stream channels are not well understood because of a lack of measured data. Therefore, we simultaneously measured discharge, using a v-notch weir and the water depth 50 m downstream of the weir in a small natural channel, in the Aono Research Forest of the Arboricultural Research Institute of the University of Tokyo Forests on the Izu Peninsula, Japan. The Manning's roughness coefficient decreased almost one order of magnitude from 1.88 to 0.14 as the water depth increased. Moreover, the coefficient was large and decreased dramatically with increasing water depth as the water surface was below the top of most of the gravel in the stream bed(maximum water depth<0.2 m). Once the water surface was above most of the gravel (>0.2 m), the coefficient then changed little with increasing water depth. The minimum Manning's roughness coefficient observed was similar to previously reported values of 0.09 to 0.23 in steep step-pool channels under high flow conditions. These findings indicate that the roughness characteristics of steep mountain streams can exceed a Manning's roughness coefficient of 0.1.

Journal

• Journal of the Japan Society of Erosion Control Engineering

  Journal of the Japan Society of Erosion Control Engineering 65 (1), 62-68, 2012

  Japan Society of Erosion Control Engineering

Keywords

• discharge
• Manning's roughness coefficient
• mean velocity
• mountain stream
• step-pool channel
• water depth

Details

• CRID: 1390001205479841152
• NII Article ID: 10030600401
• NII Book ID: AN0012035X
• DOI: 10.11475/sabo.65.1_62
• ISSN: 21874654
• ISSN: 02868385
• NDL BIB ID: 023787753
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I023787753
• Text Lang: ja
• Data Source:
  • JaLC
  • NDL
  • CiNii Articles
  • KAKEN
  • Crossref
• Abstract License Flag: Disallowed