This paper builds on the now classical discussions by Bowen [1980] and Bail
ard [1981] on the applicability and implications of Bngnold's [1963] sedime
nt transport model to nearshore profile modeling. We focus on the morpholog
ic implications of both the strengths and weaknesses of Bagnold's model, is
olating the transport terms that are well predicted (i.e., mean flow terms)
from those that are not well predicted (i.e., transport due to correlation
s between flow and sediment load). We factor Bagnold's model into a dimensi
onal transport magnitude and a nondimensional term. The nondimensional term
describes the relative importance of transport due to undertow, gravity, a
nd correlations between flow and sediment load. The transport magnitude lar
gely determines the response time of nearshore profiles. For typical nearsh
ore environments this response time was estimated to vary as a function of
incident rms wave height (H-rms) from similar to 500 years (H-rms similar t
o 0.5 m) to 2 years (H-rms similar to 3 m). The relative importance of comp
eting transport mechanisms is shown to depend strongly on the relative wave
height (defined as the ratio of the rms wave height to the local depth). S
implified nearshore transport parameterizations that are a function of this
variable were derived and were interrogated for the existence and form of
equilibrium profiles. Several differences from previously computed equilibr
ium profiles were noted. First, because the relative wave height saturates
in natural surf zones, equilibrium profiles converge to a relatively flat p
rofile near the shoreline. Second, under some situations a seaward sloping
equilibrium profile may not exist. Third, the long response times combined
with unknown stability of an equilibrium profile make it difficult to asses
s the physical connection between theoretical equilibrium profiles and prof
iles observed in nature.