EM 1110-2-1100 (Part V)
31 Jul 2003
EXAMPLE PROBLEM V-4-3
FIND:
Sectional fill volume (fill volume per unit length of shoreline) required to widen
the dry beach by 30 m.
GIVEN:
Preproject beach profiles are representative of healthy (sediment-rich) conditions.
Berm height of 2.5 m and depth of closure of 6 m.
Fill material (composite median diameter) same as native beach sand.
SOLUTION:
Equation V-4-6 gives
' 255 m 3/m
V ' 30 2.5 % 6
˙
(d) Sectional volume computations in situations when the fill and native sediments differ should be made
by considering differences between the existing profile and the design profile shape as outlined in Part V-4-
1-f-(4) and illustrated in Figure V-4-17. The BMAP software provides capabilities for calculating sectional
fill volume in cases where native and fill sediments differ in median grain size.
(e) Equilibrium profile concepts also can be used directly to make preliminary estimates of required fill
volume, when the native and fill sediments have differing composite median grain sizes. While not
recommended for final fill volume computations, these methods provide valuable insight regarding the
implications of using fill material with different grain size characteristics. Dean (1991) defines three basic
types of nourished profiles. Figure V-4-19 shows an intersecting profile, where the profile after nourishment
intersects the native profile at a depth shallower than the depth of closure; a nonintersecting profile, where
the nourished profile does not intersect the native profile before closure depth; and a submerged profile,
where after equilibrium there is no dry beach. A submerged profile is a special case of a nonintersecting
profile which occurs when insufficient volume is placed to fully develop the underwater equilibrium profile.
Dean (1991) shows that whether a profile is intersecting or nonintersecting is determined by the following
inequality:
3/2
3/2
AN
AN
< 1 , Intersecting profile
W
%
DC
AF
(V-4-7)
> 1 , Nonintersecting profile
For fill material different from the native beach sand, cross-sectional volume requirements should
be estimated with consideration given to the differences in profile slope given by equilibrium profile
parameters for native and fill sands, respectively (see Table III-3-3 for values of the A parameter for
different sand sizes), fill sand that is finer than the native material will always produce a
nonintersecting profile according to Equation V-4-7. Fill sand that is coarser than native sand may
Beach Fill Design
V-4-43
Previous Page
