Google+
Facebook
LinkedIn
Twitter
Digg
StumbleUpon
Home
Download PDF
Order CD-ROM
Order in Print
Home
>
Costal Inlets Research Program
>
> Figure 1. Schematic illustration of rip current development near a groin due to changing wave direction.
IMPLICATIONS OF MORPHODYNAMIC TIME SCALE FOR COASTAL PROTECTION
One-Line Modeling
MorphoTimeICCE04
Page Navigation
1
2
3
4
5
6
7
COASTAL
ENGINEERING
2004
2621
Breaking
Waves:1
a)
Beach
.
Breaking
Waves:2
Rip
Current
b)
.
Figure 1.
Schematic
illustration of
rip
current
development
near
a groin
due
to
changing
wave
direction.
this
rip
current,
sediment
is
transported
offshore
and
may
become,
at
least
partly
and
locally,
lost
from
the
nearshore
system.
The
plan
shape
gradually
approaches
a
new
equilibrium
shape
at
which
point
the
longshore as
well
the
rip
transport
approaches
zero.
This
transition
plays
a central
role
for
the
functioning
of
the
groin
(system).
Despite
this,
there
are
no
design
guidelines
that
take
the
variability
of breaking
wave
direction
into
account.
This
paper
discusses
the
impact
of changing
wave
direction
on shoreline
evolution
and
associated
offshore
sediment
losses
through
the
application of analytic
solutions
as
well
the
numerical shoreline
change
simulation model GENESIS. It is shown
that
1)
there
is an inherent
morphodynamic time
scale
associated
with
groin
compartments,
2)
the
offshore
losses
are
proportional
to
the
offset
between
the
forcing
and
the
response,
and
3)
losses
are
at a
minimum
when
changes
in
the
forcing
are
of
the
same
temporal
scale
as
that
of
the
response.
Shoreline
change
in
the
vicinity
of
disturbances
that
alter
transport
alongshore
is
controlled
by
the
gross
transport
rate
as
well
as
the
net
(Bodge,
1992). Kraus
et al
.
(1994)
investigated
the
functioning
of a single
groin
as a
function
the
ratio
of
the
net
transport
rate
Q
n
to
the
gross
Q
g
.
The
study
showed
that
the
impoundment on
the
updrift
side
increases
with
the
ratio
Q
n
/
Q
g
while
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business