Sedimentation of particles in horizontal channels in turbulent flow is commonly encountered in industrial processes. Investigations showed that the sedimentation velocity of particles in horizontal channels is nonsymmetrical along the cross-section of channels due to gravity. In this work, new expressions for the calculation of the sedimentation velocity of particles and the thickness of the sediment layer at the bottom of a horizontal channel are suggested. The entrainment and the transport rates of the particles from the sediment layer are also determined, and it was found that the entrainment rate is proportional to the square power of the friction velocity and inversely proportional to the viscosity of the flow. Comparisons of the suggested equations in this work with published data from the literature showed good agreement. (C) 2004 Elsevier B.V. All rights reserved.