EM 1110-2-1100 (Part V)
31 Jul 2003
6
Preproject profile
4
Postconstruction profile
Design profile
2
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-2
-4
-6
-8
0
100
200
300
400
500
Distance from Baseline, m
Figure V-4-2. Schematic illustration of preproject, postconstruction, and design profile
maintenance program can greatly enhance the survival and effectiveness of beach grass. Part V-4-1-i
provides more detailed information on dune stabilization.
(d) Preliminary estimates of dune height, width, and side slope for a beach nourishment project can be
made based on characteristics of natural dunes in the vicinity of the project. To be most effective, the crest
height of the dune should be above the limit of wave runup for the types of storms for which protection is
sought, and the beach berm in front of the dune must be of sufficient width to withstand the erosion associated
with these types of storms. If the berm in front of the dune is too narrow, the dune can quickly erode, even
for relatively frequent storms, and the benefits of the higher dune elevations will be lost. The design dune
height and width (along with the width of the berm) are usually selected based on results of an iterative
process in which the benefits are compared with the cost of each configuration. Part V-4-1-f provides more
detail on the dune/berm design process. Sometimes other factors such as real estate acquisition issues or
aesthetics are factored into the selection of dune crest elevation and width.
(3) Nearshore berm. Beach-fill projects are usually constructed via direct placement of sand on the
beach. Sometimes, in an effort to reduce cost, or because of limits in available dredge equipment, or in
response to concerns with direct placement of fill material on the beach, material is placed offshore in an
underwater berm (i.e., bar). Nearshore berm creation is intended to simulate storm bar formation by creating
an artificial shore-parallel bar to dissipate storm wave energy before impacting the beach. If the berm is
V-4-4
Beach Fill Design
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