ERDC/CHL CHETN IV-__
DRAFT 23 March 2005
Coastal Barrier Island Breaching, Part 2:
Mechanical Breaching and Breach Closure
By Ty V. Wamsley, Nicholas C. Kraus
US Army Corps
of Engineers
describes case studies of the mechanical closure and creation of coastal barrier island breaches.
Emphasis is on breaches that form near inlets, with examples also given of breach opening for
environmental enhancement. Part 1 in this technical note series reviews the causes of breaching
and measures to prevent breaching (Kraus and Wamsley 2003). Subsequent technical notes will
describe models under development in the Coastal Inlets Research Program for predicting the
inception and evolution of breaches.
BACKGROUND: In a coastal context, a breach is a new opening in a narrow landmass such as
a barrier spit or barrier island that allows water to flow between the water bodies on each side.
Every year around the coast of the United States, breaches occur at barrier islands, barrier spits,
and closed river mouths. Breaches occur naturally or they can be purposefully dug or dredged,
and a breach may have positive or negative environmental consequences. Unintended breaching
of barrier islands and barrier spits is often a serious concern to society.
The U.S. Army Corps of Engineers (USACE) is routinely called upon to permit coastal breach
closing and opening operations. In emergencies, the USACE may take an active role in
designing and supervising mechanical closure or opening of breaches. Mechanical cutting of
breaches typically requires local, state, and federal permits. Discharges of dredged material or
fill into wetlands or other waters of the United States are regulated by the USACE under Section
404 of the Clean Water Act. The USACE has permit authority under provisions of Section 404
of the Clean Water Act (33 U.S.C. 1344) and under Section 10 of the Rivers and Harbors Act of
1899 (33 U.S.C. 403), the latter concerning navigable waters.
Breaches can: cause loss of property due to flooding, wave attack, and erosion; loss of
navigability in adjacent inlets sharing the same water body as the breach; destroy roads,
highways, utilities, and other infrastructure; and create environmental concern over loss of
habitat and unwanted increases or decreases in water level and salinity. Breaches usually enlarge
rapidly, increasing the complexity and cost of breach closure construction with time. Therefore,
it is often desirable to mechanically close breaches in the most timely and efficient manner
possible. Breaches that occur adjacent to or near Federal navigation projects with jetties are of
particular concern, and an overview of this situation is given next.
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