Figure 12. Diagram of beach states using time exposure video images modified from Lippmann and Holman (1990). Numbers
indicate the percent of time that the nearshore morphology is unbarred, linear, mildly crescentic, or crescentic
during FRF experiments has also
procedures, and models for use by
2000). Other authors developed
spurred the development and valida-
the Corps. For example, FRF data
novel methods for using sonars to
tion of models for alongshore
were used in the development and
accurately monitor bottom bed forms
momentum balances (Feddersen et
validation of the SBEACH (Larson
(Gallagher et al. 1998b; Thornton et
al. 1998; Lentz et al. 1999), sand
and Kraus 1989) profile change
al. 1998).
bar generation and migration
model and GENESIS (Hanson and
The Duck location has served as
(Sallenger et al. 1985; Holman and
Kraus 1989) a shoreline change
an ideal site for the extension of
Sallenger 1993; Thornton et al.
model. Corps Districts use software
these findings to other locales world-
1996; Gallagher et al. 1998a), wave
and survey procedures developed or
wide. The variability in waves, cur-
energy transformation (Lippmann,
tested at the FRF. Wave observa-
rents, and morphology at Duck has
Brookins, and Thornton 1996; Elgar
tions have contributed to more real-
allowed hypotheses developed using
et al. 1997), and the vertical struc-
istic wave modeling. Instrument tests
data from the FRF to be validated
ture of cross-shore currents (Haines
and evaluations conducted at the
elsewhere. For example, the fact
and Sallenger 1994; Faria et al.
FRF have led to more robust and
that Duck experiences both reflec-
2000). There is little doubt that the
reliable gauging at remote Corps
tive and dissipative conditions
existence of the FRF has resulted in
sites. Video techniques developed at
allowed the establishment of a rela-
publications that have extended our
the FRF are being used in innova-
tive scaling for infragravity motions
understanding of the complex inter-
tive ways to address unique Corps
with respect to offshore incident
actions between hydrodynamic and
problems. Continued use of the
wave conditions (e.g., Holman and
morphodynamic processes.
Duck data set will raise the level of
Sallenger 1985; Howd et al. 1991;
sophistication of the next generation
Holland and Holman 1999). Interpre-
Importantly, this research is lead-
of Corps nearshore numerical
tation of the extensive data collected
ing to improved technology,
models.
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