A frequency-domain Boussinesq model with good linear shoaling, improve
d linear dispersion characteristics and a dissipation formulation to a
ccount for wave breaking is extended to include the computation of the
vertical structure of the horizontal velocity. The extended model is
used to predict bottom velocities and resulting velocity variance and
skewness in (partially) breaking irregular waves. The comparison of me
asured and computed velocity moments indicates that for moderately lon
g waves the spectral Boussinesq model can be successfully used for sed
iment transport purposes. For shorter waves the crest velocity values
of the higher waves are significantly underestimated, and as a result
the velocity skewness as well. (C) 1997 Elsevier Science B.V.