Mantoloking Sea Wall
Owner New Jersey Dept. of Environmental Protection, Bureau of Coastal Engineering
Lead Design Firm Mott MacDonald
General Contractor EIC Associates Inc.
In October 2012, Hurricane Sandy destroyed large parts of the New Jersey shore town of Mantoloking, and an emergency plan was needed to restore it. In order to prevent future damage from similar storms, construction of a sea wall began along the town’s oceanfront.
“This project will help protect a segment of coastline that was breached during Superstorm Sandy, especially offering protection to Route 35 and residents and businesses that were battered,” says New Jersey Dept. of Environmental Protection Commissioner Bob Martin. “Coupled with the forthcoming coastal protection project by the U.S. Army Corps of Engineers, this particularly vulnerable section of the Jersey shore will be more resilient for future severe weather events.”
Mantoloking’s 11,000 ft of oceanfront retreated roughly 40 ft, with a loss of about 500,000 cu yd of sand. By the summer of 2014, only 200,000 cu yd had been recovered, leaving homes and businesses vulnerable.
Public works crews used bulldozers to create and maintain artificial sand dunes as a temporary protective measure against storm damage until a more permanent and reliable protective measure could be put in place.
Construction of the permanent structure began in July 2014, with crews using specialized pile drivers to embed 45-ft-long steel sheets along the beach at the foot of the Mantoloking Bridge.
Roughly 150 ft of sea wall was constructed per day, with the toe of each sheet driven to 30 ft below sea level. The top elevation of the wall matched the Federal Emergency Management Agency’s 100-year storm level, and any steel sheeting exposed above ground was later covered with sand to further secure the area.
“Typically, we expect that if it stays buried in the sand, it should last for 100 to 150 years, and if it is exposed to the surf, we’re looking at a lifespan of 50 years,” says Robert Mainberger, project manager at Mott Macdonald. The project was completed in early 2015.