ROUGHNESS CHARACTERISTICS OF ROCK-LINED CHANNELS

This investigation was to improve the design of rock lined channels. By an extensive review of the literature it became apparent that there exist important functional relationships between Manning's n and the Froude number, Reynolds number, relative roughness, and slope. To establish these relationships, over one hundred independent field and laboratory data-sets were subjected to statistical analysis. Results revealed that for rough channels n is influenced by the Froude number and the slope. In smooth channels (y > 6 D sub 50) n is primarily controlled by the Reynolds number. Based on these results the selection of the proper roughness factor n for drainage channels lined with larger rocks may be aided by the relationship n = 0.38 (S to the 0.57th power)/F where S is the channel slope and F is the Froude number of the flow. This formula is for the initial determination of the magnitude of n. As a consequence of these results, the maximum Manning's n for large channels specified in the ODOT Location and Design Manual was recommended to be changed from n = 0.06 to n = 0.04. (Author)

  • Corporate Authors:

    University of Akron

    Department of Civil Engineering
    Akron, OH  United States  44325-3905

    Ohio Department of Transportation

    P.O. Box 889
    Columbus, OH  United States  43215

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Simon, A L
    • Sarikelle, S
  • Publication Date: 1980-7-1

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 47 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00334673
  • Record Type: Publication
  • Report/Paper Numbers: FHWA/OH-80/007 Final Rpt.
  • Contract Numbers: St Job No. 14310(0)
  • Files: TRIS, USDOT, STATEDOT
  • Created Date: Sep 16 1981 12:00AM