EM 1110-2-1100 (Part V)
31 Jul 2003
Beach Fill Design
V-4-1. Engineering Aspects of Beach-Fill Design
a. Project objectives.
(1) The primary function of a Federal beach nourishment project is to provide improved protection to
upland structures and infrastructure from the effects of storms. Figure V-4-1 shows how storms damage
upland property. The top panel shows the beach under normal wave and water level conditions. The letters
mhw and mlw denote the mean high and low water lines, respectively, which represent the normal range of
tidally-induced water level fluctuations. The elevation of the natural beach berm is above the normal high
tide elevation. Under nonstorm conditions, breaking waves are confined to the seaward face of the berm.
The berm and dune act as a protective buffer between upland structures and the water and waves. Sites with
little or no sand buffer are candidates for shore protection projects. The middle panel shows the beach during
a storm. The water level is elevated above the normal range. This exposes higher beach elevations to the
action of breaking waves, which erode the berm and transport the sand offshore and along the beach. Sand
moved offshore during the storm continues to aid in dissipating wave energy; it often forms a shore-parallel
bar system. In this panel, a scarp forms on the seaward face of the dune, but the dune remains relatively intact
and protects the structures behind it. Had there been no dune, or a much narrower berm, the structure may
have been damaged as shown in the bottom panel. The lower panel shows a more severe condition, in which
even higher water levels and wave action have completely eroded the dune. Some of the dune material is
transported offshore. Some is transported onshore and deposited as a result of wave runup and overwash
processes. The exposed structure is subject to damage by undermining, flooding, and by waves breaking
directly on it.
(2) A beach nourishment project typically involves constructing a wider beach and/or more substantial
dune to reduce storm damage relative to the level of damage that would have resulted without the project. The
level of storm protection provided by a nourishment project is not an absolute measure due to the
uncertainties in the frequency of high intensity storms. There is always some chance, or risk, that a storm will
cause property damage even with the project in place. The level of protection, reduced in the aftermath of
a major storm, will remain compromised if proper poststorm maintenance is not performed. The level of
protection will also be compromised if scheduled periodic renourishment, which is usually a key element of
the design, is not performed when needed.
(3) The wider beach created through construction of a nourishment project also provides recreational
benefits. Enhanced recreational opportunity can also be a project objective.
b. Project features. Beach nourishment projects typically involve construction of one or several of the
following features: berm, dune, feeder beach, nearshore berm, dune stabilization (i.e., sand fences or
vegetation), or structural stabilization (i.e., groins). There are also several aspects of a beach nourishment
project that specifically address the future integrity of the dune/berm. These include: periodic renourishment,
advance nourishment, and emergency maintenance. These project features are discussed in more detail in
the following paragraphs.
(1) Beach berm.
(a) The beach berm is the primary feature of most beach nourishment projects. Most beaches have a
natural berm or berms. The lowest berm closest to the water is formed by the uprush of wave action during
the ordinary range of water-level fluctuations. Sometimes, several berms will be noticeable at slightly higher
Beach Fill Design