Hydraulic Model Development using HEC-RAS and Determination of Manning Roughness Value for Shatt Al-Rumaith

Muthanna Journal of Engineering and Technology

Volume (4), Issue (1), Year (30 June 2016), Pages (09-13)


Research Article By:

Ameera Mohamad Awad

Corresponding author E-mail: ameer.wisam2005@gmail.com


Selection of appropriate Manning’s coefficient is critical to the accuracy of computed water surface profiles. Moreover, estimation of channel roughness parameter is of key importance in the study of open- channel flow particularly in hydraulic modeling. Hence, it is essential to calibrate the channel roughness coefficient for open channel whether natural or artificial. In the present study, it is attempted to calibrate the value of Mannnig’s “n” coefficient by comparing the computed water surface profiles with observed one, using HEC-RAS steady flow model for shatt al-Rumaith channel in Al-Muthanna (Iraq). For this calibration, the flows for the year 2014 has been considered. It is found that the value of Manning’s roughness coefficient for shatt al-Rumaith shows a good agreement between the computed with observed water surface profiles, is n=0.023 and n= 0.04 for main channel and floodplain respectively.

Keywords: Manning’s roughness coefficient, HEC-RAS model, calibration, water surface profiles, shatt Al-Rumaith.

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