Author(s): Wrc Myers; Jf Lyness; Jb Cassells
Linked Author(s):
Keywords: Compound channels; Flow resistance; Conveyance estimation
Abstract: The estimation of roughness and conveyance in river channels is complicated by variations in geometry and boundary roughness. Estimating flood flows is particularly difficult because of compound cross-sectional geometries and because of the difficulties of flow gauging. Results are presented of a laboratory study aimed at suggesting a method of estimating roughness coefficients for compound channels. Stage discharge relationships and Manning’s n values are presented for trapezoidal and compound cross-sections having smooth, sand and surface penetrating roughness patterns. It is then suggested that a possible methodology for Manning’n estimation in compound channels is by means of a comparison with channels of simple shape which may be known or easily estimated. Graphs of Manning’s n ratio are presented, which may point the way to such methods and may be capable of extrapolation to prototype situations when more field data are available.
Year: 1999