72.0 
@0.0 
B.0 
NUTT 
24.0 
12.0 
| 
= 
= 
= 
a 
=a 
= 
[—-———] 
== 
_ = 
== 
— =m 
uw = 
~— =a 
(a) 
z =< 
fa) 
on => 
— = 
n [I 
no i] 
Ww [=] 
oI 
Oo i= 
enh 
i) 
a i 
——} 
= ———<—} 
= am 
i————F 
=I 
_ = 
~< —— 7) 
< oa 
aa 
= <= 
= 
a 
<= 
<= 
el 
= 
=a 
==] 
ea 
| 
el 
TUT 
RECURRENCE INTERVAL (YEARS) 
DESIGN C: 30-FT BERM WIDTH HURRICANES AND NORTHEASTERS 
Figure 48. Maximum recession-recurrence design curve for combined 
hurricanes and northeasters for Design C: 30-ft berm width 
Variability Factor 
175. The recession-recurrence analysis procedure developed for this 
project treated storm descriptors in a stochastic (random) manner. The beach 
was idealized as having a known cross-section, and longshore variability of 
the beach profile was neglected. In nature, the hydraulic eroding forces and 
the beach profile will individually exhibit longshore variability. These 
separate variabilities are site-dependent and also change in time. Therefore, 
it is impossible to quantify, in a deterministic manner, the mesoscale detail 
of the longshore variation in erosion potential due to storm action. 
176. Although an estimate of the longshore variability in storm erosion 
potential cannot be calculated at present, it is possible to arrive at an 
estimate based on measured variations. Birkemeier et al. (1987) and Savage 
and Birkemeier (1987) examined the variation in erosion associated with 588 
different profiles at seven East Coast localities for 13 storms. A variabil- 
ity factor was defined to encompass 75 percent of the observed change. This 
value can be interpreted as the multiplier of the median required to include 
98 
