channel narrowed, the currents became stronger, and the depth increased. The strong shear stress
scoured material from both banks. With the losses on the north side replenished by the dredge,
the inlet migrated south, even with the makeshift revetment provided by the local concerns.
Figure 5. The Buxton breach, 29 January 1963, looking toward the sound (Wilmington
District 1963).
On 17 February, the second dredge finally reached the site. The two dredges pumped a
combined 55,000 cu yd over a 3-day period to close the breach. The second dredge provided
enough pumping capacity to overcome the breach flow. The Wilmington District (1963) noted
that "it seems quite clear that the incremental rate of discharge provided by the (second dredge)
spelled the difference between futility and success". All sand was pumped from the north breach
bank.
The Buxton Inlet experience taught that if a breach is to be closed by pumping alone, the
pumping capacity must be sufficient to overcome scour as the breach closes. In addition, to
reduce channel migration, the breach should be filled from both sides, or the bank opposite the
fill operation should be revetted in some way.
Moriches Inlet, New York. Moriches Inlet is located on the south shore of Long Island, NY,
45 miles west of Montauk Point and 80 miles east of New York City. The inlet connects
Moriches Bay to the Atlantic Ocean and is protected by two rock jetties. A northeast storm in
January 1980 breached the barrier island approximately 1,000 ft east of Moriches Inlet. The
initial breach width observed on 16 January was estimated at 300 ft, and the depth was
approximately 2 ft mean low water (mlw). The breach was surveyed on 20 January and had
widened to 700 ft with an average depth of just over 3 ft mlw. The breach continued to grow,
and by the fall of 1980 it was approximately 2,900 ft wide with a maximum depth around 10 ft
mlw. Current velocity in the breach prior to its closure was estimated at as much as 5 ft/sec.
The breach caused local concern about increased exposure to storm flooding in the backbay, as
well as possible harm to the shellfish industry due to increased bay salinity. As a result, the New
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