Environmental Engineering Reference
In-Depth Information
(a
)
(b
)
10
0.2
0.1
5
0
0
-0.1
-5
-0.2
-10
-0.3
-15
1980
1985
1990
1995
2000
2005
0
200
400
600
800
1000
Time (years)
Cross-shore distance (m)
U1
V1
H1
H2
H3
(c
)
5
4
3
2
1
0
-1
-2
0
1
2
3
4
Wave Height (m)
G1
G2
G3
Fig. 16.9
Results of the canonical correlation analysis (CCA) betweenwave height probability density functions (pdfs)
and beach profiles: (a) temporal amplitudes of the first CCAmodes (U
1
and V
1
); (b) spatial amplitudes of the first three
CCAmodes for profile elevation (H
1
H
3
); and (c) wave height amplitudes of the first threeCCAmodes for wave height
pdf (G
1
G
3
).
hydrodynamics is calculated assuming the bed
level remains constant. Then the sediment trans-
port is calculated according to the results of the
hydrodynamicmodule. Following on fromthis the
bed level is then updated according to the predic-
tions made by the sediment transport module.
Further details of this modular approach can be
found in Johnson and Zyserman (2000), Zyserman
and Johnson (2002), Karambas and Koutitas (2002)
or Pedrozo-Acu
˜
a et al. (2006).
An important consideration when dealing with
hydro-morphodynamic models is the fact that
morphological evolution happens on a longer
timescale than hydrodynamic evolution. Hydro-
dynamics can vary greatly over one wave period
whereas the morphodynamics requires a greater
timescale to evolve. To overcome this problem an
appropriate time step needs to be chosen to update
the bathymetry; typically this is a longer time step
than that of the hydrodynamics. In order to show
how uncertainties with regards to this selection of
the time step can be avoided, this section intro-
duces a sensitivity test of this parameter and its
effects on the induced bed level changes. This
is done with results from the morphological
model presented in Pedrozo-Acu ˜ a et al. (2006).
