Analysis of Manning coefficient for small-depth flows on vegetated beds

✍ Scribed by R. García Díaz

• Book ID: 102265553
• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 140 KB
• Volume: 19
• Category: Article
• ISSN: 0885-6087
• DOI: 10.1002/hyp.5820

✦ Synopsis

The limitations of Manning's formula are analysed when it is in extreme conditions, and more specifically with smalldepth flows on natural-vegetation beds. A thorough analysis is made of research carried out on macro-rough beds, placing particular emphasis on vegetated beds. Research carried out to date on the roughness of vegetated beds and macro-roughness is commented on, including that carried out at the Laboratory of Hydraulics and Hydrology of the Forestry Engineering Faculty (Polytechnic University of Madrid). The work was done in two phases, the first in a laboratory channel with artificial vegetation and the second in natural beds. The results of the experimental research allow the development of a new approximate method of determining Manning coefficient according to the Froude number. This method may be applied in extreme conditions, both in small depths and steep slopes. It was proved that the Manning coefficient depends not only on roughness height, but also on depth and slope values; thus, it is advisable to choose the appropriate method for its calculation.