Title: Effect of roughness coefficient on discharge and flow depth by using hydraulic model for Nethravathi River Basin, India

Authors: Pramodkumar Kappadi; M.K. Nagaraj; Paresh Chandra Deka

Addresses: Department of Applied Mechanics and Hydraulics, National Institute of Technology Karnataka, P.O. Srinivasnagar, Surathkal, 575025, India ' Department of Applied Mechanics and Hydraulics, National Institute of Technology Karnataka, P.O. Srinivasnagar, Surathkal, 575025, India ' Department of Applied Mechanics and Hydraulics, National Institute of Technology Karnataka, P.O. Srinivasnagar, Surathkal, 575025, India

Abstract: The river stage and discharge are dynamic due to various factors affecting the flow characteristics in a natural channel. The channel roughness plays an important role since it is not a constant parameter and varies along the length of the river. The objective of the present study is to assess the variation of Manning's roughness coefficient on flow characteristics of Nethravathi River. In the study, 1D Saint-Venant equation-based HEC-RAS hydraulic model was used to simulate the effect of roughness coefficient (Manning's coefficient n) on discharge and stage of river flow. The model result showed good consensus between model computed flow discharge values and observed flow discharge measured at downstream gauging station. The study found that the computed stage values increased whereas the associated peak discharge decreased with the increase in Manning's roughness coefficient. The stage-discharge rating curves revealed that Manning's n value is relatively more sensitive at higher discharge values.

Keywords: hydraulic model; roughness coefficient; HEC-RAS; discharge and stage.

DOI: 10.1504/IJHST.2021.112661

International Journal of Hydrology Science and Technology, 2021 Vol.11 No.1, pp.114 - 124

Received: 02 Jan 2019
Accepted: 14 Jun 2019
Published online: 26 Jan 2021 *

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