Appendices
313
3
BH 2
Z =
1
1
(108)
(s --1) 2 • D 2
With dimensions the same as for (107), D however in (108) is the sediment mean
diameter in the beach face near SWL.
For a storm beach surf zone, the cross-sectional water area is given by Sitarz as •
1
2
3.4g 2 • H l T l
A=
3 3
1
l
(109)
(S --1) 2 " D 2
wherein"
T l = significant wave period
3
m
g = 9.81 ---T
D -- median sediment diameter across surf zone
s as in (107) and H 1 as in (109).
3
If d~ is t surf zone mean depth"
A
ds=-Z
Z and ds can be overlain to predict likely beach degradation. However,
recognizing a realistic mean energy input and a stable profile for sediment size
remains problematic given that swell waves vary hourly and weekly in height.
When an offshore bar forms, a fully fledged swell profile can only be labeled such
after the bar has been entirely swept back to the beach and only then is the bed
'In equilibrium". Moral • cross-sections should be made at the end of the period
of swell.
313
3
BH 2
Z =
1
1
(108)
(s --1) 2 • D 2
With dimensions the same as for (107), D however in (108) is the sediment mean
diameter in the beach face near SWL.
For a storm beach surf zone, the cross-sectional water area is given by Sitarz as •
1
2
3.4g 2 • H l T l
A=
3 3
1
l
(109)
(S --1) 2 " D 2
wherein"
T l = significant wave period
3
m
g = 9.81 ---T
D -- median sediment diameter across surf zone
s as in (107) and H 1 as in (109).
3
If d~ is t surf zone mean depth"
A
ds=-Z
Z and ds can be overlain to predict likely beach degradation. However,
recognizing a realistic mean energy input and a stable profile for sediment size
remains problematic given that swell waves vary hourly and weekly in height.
When an offshore bar forms, a fully fledged swell profile can only be labeled such
after the bar has been entirely swept back to the beach and only then is the bed
'In equilibrium". Moral • cross-sections should be made at the end of the period
of swell.