At the Fish Pier the tide range was 3.6 ft (1.1 m) and has increased to 4.6 ft
maximum ebb and 3.2 ft/s (1.0 m/s) at maximum flood (U.S. Army Engineer
Division, New England, 1989). The ebb flows reach their maximum near low
water and are confined to the main channel, while the maximum flood current
occurs near high water and the flows are spread out over the swash platform
(FitzGerald and Montello 1993).
Storms have played an important part in shaping the coastline in this area.
Extratropical northeasters and tropical storms both have impacted the area. Nauset
Spit was breached on 2 January 1987, during a severe northeaster that coincided
with a perigean spring tide (Liu et al. 1993). The storm surge allowed overwash of
the spit in a low spot with few dunes. As the storm subsided the next day, a mean-
dering surge channel was present in the overwash fan allowing water to flow in
and out of Chatham Harbor throughout the entire tidal cycle. Oblique aerial
photographs taken a few days after the storm indicated that the dominant flow was
toward the bay, with a small flood shoal forming. Two more northeasters occurred
in January and February 1987, resulting in the growth of the breach to 1,706 ft
(520 m) by March (Liu et al. 1993). Major storms have continued to impact the
coast since the breach that have been a driving mechanism in inlet morphology
change. Hurricane Bob in August 1991 and the Halloween Storm in October
1991are examples.
Problem
The Town of Chatham's mainland shoreline, located on the west side of the
bay, was a relatively stable inner-estuary shoreline before the inlet formed. The
Chatham Harbor area and mainland bay shoreline became exposed to the direct
force of ocean waves and enhanced tidal currents after the inlet formed. The
shoreline from Andrew Hardings Lane to the Hawthorne Hotel (south of Caflin
Landing) was eroded some 175 ft (53 m) landward, with the loss of two town
landings and nine homes (U.S. Army Engineer Division, New England, 1989),
until the shoreline was armored. A complex multishoal flood delta formed in
Chatham Harbor and has evolved into a channel shoaling and migrating problem
over time. Maintaining a navigation channel to the Fish Pier, Chatham's main
commercial fishing port for some 80 commercial fishermen has proven difficult
and has restricted the response capability of the U.S. Coast Guard which operates
out of the Fish Pier.
In September 1987, Congress requested that the U.S. Army Corps of Engi-
neers undertake a study of the new breach and to determine the feasibility of
alternative measures to reduce shoreline damage and navigation hazards
(U.S. Army Engineer Division, New England, 1989). The U.S. Army Engineer
Research and Development Center's (ERDC) Coastal and Hydraulics Laboratory
(CHL), formerly known as the Coastal Engineering Research Center (CERC), had
assisted the New England District, formerly New England Division, in a 1989
study of the first 3 years of evolution of the new inlet (Weishar, Stauble, and
Gingerich 1989). To maintain a navigation channel, the New England District
developed a plan to dredge the anchorage at Aunt Lydia's Cove and to dredge an
6
Chapter 1 Introduction