A 3D numerical model for calculating how and sediment transport in open cha
nnels is presented. The flow is calculated by solving the full Reynolds-ave
raged Navier-Stokes equations with the k - epsilon turbulence model. Specia
l free-surface and roughness treatments are introduced for open-channel flo
w; in particular the water level is determined from a 2D Poisson equation d
erived from 2D depth-averaged momentum equations. Suspended-load transport
is simulated through the general convection-diffusion equation with an empi
rical settling-velocity term. This equation and the flow equations are solv
ed numerically with a finite-volume method on an adaptive, nonstaggered gri
d. Bed-load transport is simulated with a nonequilibrium method and the bed
deformation is obtained from an overall mass-balance equation. The suspend
ed-load model is tested for channel how situations with net entrainment fro
m a loose bed and with net deposition, and the full 3D total-load model is
validated by calculating the how and sediment transport in a 180 degrees ch
annel bend with movable bed. in all cases, the agreement with measurements
is generally good.