Turbulent Velocity Profiles and Boundary Shear in Gravel Bed Rivers

Abstract

Vertical profiles of turbulent streamwise velocities in gravel bed rivers are investigated. Field measurements made at high and low flows with electronic pitot tubes show logarithmic velocity profiles to extend over much of the flow depth. For the gravel bed rivers studied the velocity at 0.6 of the total depth was generally a good indicator of depth-averaged flow velocity. An unambiguous definition of flow depth is adopted to deal with situations where the bed is uneven or moving. When hydraulic roughness