  We present a study of sediment transport in the creeping and saltation
regime. In our model, a bed of particles is simulated with the conventional
event-driven method. The particles are considered as hard disks in a 2d domain,
with periodic boundary conditions in horizontal direction. The flow of the
fluid over this bed of particles is modeled by imposing a force on each
particle that depends on the velocity of the fluid and its height above the
bed. We considered two velocity profiles for the fluid, parabolic and
logarithmic. The first one models laminar flow and the second corresponds to
turbulent flow. For each case we investigated the behavior of the saturated
flux. We found that for the logarithmic profile, the saturated flux shows a
quadratic increase with the strength of the flow, and for parabolic profile, a
cubic increase. The velocity distribution functions are used to interpret the
results.
