A morphological model for the development of local-scour holes behind
structures is developed, based on the 2-D Navier Stokes and convection
-diffusion equations. The bed-load (transport) and the concentration a
t a reference level close to the bed are prescribed using a stochastic
al approach for the instantaneous bed shear-stress. The standard devia
tion of the latter is closely related to the turbulence energy in the
mixing layer and to the bed turbulence. The computed developments of l
ocal-scour holes in scale models and in prototype are compared to meas
ured developments. Reasonable results regarding flow velocities, sedim
ent concentrations and bed configurations as function of time are obta
ined, promising reliable predictions for local-scour holes in practice
.