MUTHANNA JOURNAL OF ENGINEERING AND TECHNOLOGY (MJET)
Hydraulic Model Development using HEC-RAS and Determination of Manning Roughness Value for Shatt Al-Rumaith
Research Article:
Ameera Mohamad Awad*
Department of Civil Engineering , College of Engineering , University of Al- Muthanna.
E-mail addresses: hudamohammad20@gmail.com
ABSTRACT
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 AlMuthanna (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=0.023and n= 0.04 for main channel
and floodplain respectively
Keywords:Manning’s Roughness coefficient , HEC-RAS model ,Calibration , water surface profiles, shatt Al-Rumaith