26 
LEGEND 
— p208 941017 1200 
——p208 941208 1200 
p208 950323 1536 
--~p208 950522 1200 
---p208 950616 1200 
——p208-954008—4200, 
Lu 
© 
< 
© 
x 
° 
=) 
ey 
— 
200 400 600 800 
Distance Offshore (ft) 
Figure 22. Beach profile evolution at sta 208 
Beach Profile Equilibrium 
The shape of the beach profiles at the hot spot in comparison with the 
equilibrium profile is useful in assessing whether additional cross-shore 
adjustment and consequential shoreline retreat will occur. Dean (1977, 1991) 
has demonstrated that an equilibrium profile relationship, y = Ax”*, can be used 
to estimate the equilibrium beach profile shape, where y is water depth and x is 
distance seaward of the shoreline. The empirical shape factor, A, has been 
shown to be related to the median sediment diameter, d;, (Moore 1982). Using 
the equilibrium profile relationship and available sediment grain-size 
distributions, an assessment of the beach profile’s approach to cross-shore 
equilibrium is made. 
Sediment characteristics 
The median grain size diameter of the beach fill was quantified to specify an 
equilibrium beach profile. Sediment samples were collected between October 
1994 and January 1995. Four sediment samples were collected at 200-ft 
alongshore intervals between sta 246 and 276 with sampling locations at the 
backshore beach, midberm, mean high water, and mean low water. The analysis 
of the sand samples indicates that grain sizes across the beach fill poorly sorted 
(with exception of the mean low water samples), as expected for a newly placed 
beach fill that has not been subjected to much wave activity. 
Chapter 3 Beach Profile Evolution 
