Fort Fisher Revetment Project Nears Completion (March 1996)

[Originally published in the March, 1996 – FPHPS Newsletter]

At last month’s [Feb, 1996] meeting of the Federal Point Historic Preservation Society, Mr. Bill Dennis, a civil engineer with the US. Army Corps of Engineers – Wilmington District, presented a thorough site history and review of the Fort Fisher revetment project to a well-attended audience. Mr. Dennis, a native of New Jersey, began his slide presentation and discussion with a quick overview of the Federal Point area and how changes in its shape led to a need for a protective seawall to save the fort.

In 1761 a hurricane drastically reshaped Federal Point when it opened a passage known as New Inlet between the ocean and the Cape Fear River.

New Inlet, however, later played an important role during the Civil War as an entrance for sleek, fast blockade runners to slip past the Union fleet and enter the river under the protective guns of Fort Fisher. These ships were able to successfully deliver their valuable cargoes to Wilmington and on to the rest of the Confederacy until early 1865.

The Rocks2

‘The Rocks’ from Battery Buchanan to Zeke’s Island

Following the war, Federal Point again underwent a major transition in appearance when the US. Army Corps of Engineers closed New Inlet to improve river navigation. During the 1870s and 1880s the Corps built a stone structure known as “The Rocks” in two sections across the inlet and swash that still exists today.

The upper section of the dam extended from Battery Buchanan on Federal Point to Zeke‘s Island, a distance of 5,300 feet. The continuation of the lower section known as the Swash Defense Dam from Zeke’s Island to Smith’s Island [Bald Head Island], a distance of 12,800 feet, made the entire closure just over 3 miles in length.

Ft Fisher vs Erosion

Erosion at Ft. Fisher

In addition to the natural deterioration of Federal Point, serious erosion problems occurred near Fort Fisher alter the state intentionally removed coquina rock from the shore just north of the earthworks during the 1920s for use as road construction fill. Since that time approximately 200 yards of sea front has been lost to wave action.

This loss forced the state in the early 1950s to realign the very same highway that had been built with the use of the coquina rock. The North Carolina Highway Department, and later aided by local communities, then began dumping concrete and other large construction debris along the sea front near Battle Acre. As a further means of slowing erosion at Fort Fisher, the state placed a line of rocks along the shoreline in 1970. Storms since that time showed the revetment to be too short. Shoreline erosion continued at a rate of nearly 10 feet per year.

Since the end of the Civil War the ocean has claimed nearly half of the fort.

A more substantial solution to the site erosion problem came in 1995 when matching federal and state funds for a larger revetment project became available. The state and Corps of Engineers approved a plan for a permanent seawall based upon a design of Mr. Dennis.

After two years of planning, an acceptable design called for the construction of a 3,040-foot seawall to extend from south of Battle Acre to north of the Fort Fisher mounds.

Bids went out for the construction of the seawall. Selected for the construction project was Misener Marine Construction, Inc. of Tampa, Florida, at a bid of 4.6 million dollars.

Fort Fisher Rocks and BeachWork on the project began in June 1995, and included a multi-layered rubble revetment with circular tie-ins to natural ground on both ends of the site.

Beginning on the south end, the construction company dug a trench to 3.5 feet below mean sea level in which to lay the revetment ends. Within the trench at both ends, and along the shoreline, a fabric liner was first applied topped by a layer of gravel. Slightly larger bedding stone was then applied and finally a layer of armor stone.

The armor stone, weighing approximately two tons apiece, came from a quarry near Raleigh, while the smaller bedding stone was mined near Castle Hayne.

Approximately 68,000 tons of rock form the seawall.  Along Battle Acre the revetment overlaid most of the preexisting rubble. To prevent the new stone from washing into the sea from the sloping shoreline, Misener Marine placed a line of concrete sta-pods at the toe of the protective stone. Nearly four hundred of the pods, weighing 5 tons each and shaped like a tri-pod, were interlocked in a parallel row to the shoreline.

Reventment - Ft FisherSticking slightly above the water, marine algae soon covered the sta-pods.  On December 15 , 1995, Misener Marine placed the last rock in the revetment—nearly three months ahead of schedule.

The revetment rises slightly above the natural ground elevation at about 12-15 feet above sea level. Behind the revetment, sand was placed to form a gentle slope from the crest of the revetment to the existing ground. Currently landscaping with trees and scrubs is occurring near the revetment.

3,200-foot seawall completedat Fort Fisher Museum and Earthworks.

3,200-foot seawall completed (April, 1996)
at Fort Fisher Museum and Earthworks.

A security fence, walkway with stairs leading down to the beach on either end, and two observation gazebos are being constructed. The landscaping and construction projects are expected to be completed by April.

The new revetment should halt the ocean-side erosion of Federal Point for the next fifty years.

Mr. Dennis summarized his work on the design and construction of the seawall project when he jokingly indicated, “It took a Yankee to finally save Fort Fisher.”

 

March 1996 Newsletter (pdf) – Federal Point Historic Preservation Society

Changes to the Federal Point Landscape – webpage – Federal Point Historic Preservation Society

US. Army. Corps of Engineers:
Revetment stability study,  Fort Fisher State Historic Site