Looking out from a walkway in Davis Park, a community on New York’s Fire Island, a barrier island off Long Island’s south shore, dredgers pump sand onto the shore and spread by bulldozers at a steady clip. Seems simple enough. Not quite; much takes place before a grain of sand reaches shore.
Work & Resources
“Dredging and placing sand has several components that require a great deal of planning and resources,” commented Robert Vohden, project manager, adding, “Just mobilizing a dredge can cost several million dollars, and acquiring real-estate easements can take several years.”
Fire Island is said to be the only significant barrier island in the U.S. without paved roads to go with its all-sand beaches. Davis Park is a hamlet on Fire Island in the Town of Brookhaven in Suffolk County, off the south shore village of Patchogue, Long Island, which lies within the Fire Island National Seashore.
Hurricane Sandy Impact
In 2012, Fire Island residents and business owners watched their coastline being severely damaged by Hurricane Sandy. With the passage of the Disaster Relief Appropriations Act of 2013, the Army Corps’ New York District began ongoing coastal storm risk management projects and studies in the Northeast, including the Fire Island Inlet to Moriches Inlet Stabilization Project, referred to as FIMI. The Army Corps moved forward with the project that some residents, business owners and elected officials applauded.
This is one element of the project replenishing sections of 15 miles of coastline damaged by Hurricane Sandy. Dunes, home relocations and public-access walkways round out a comprehensive $281 million flood-risk reduction project expected to be largely complete by summer 2020.
The process of beach replenishment (or nourishment) is a technique involving pumping sand onto an eroding shoreline for the purpose of reducing storm damage and increasing protection to coastal development and infrastructure.
Two hopper dredges are being used for the project. A hopper dredge is the source where a huge ‘vacuum’ sucks up sand and water. The intake travels through grating which filters out debris. The sand and water flows through an underwater pipe to the beach. The dredged material continues through a pipe that runs down the beach to the work area. The material gushes out the end of the pipeline into a ‘basket’ that serves as a fine-screen filter which eliminates debris. In all, more than seven million cubic yards of sand will be placed on shore when the project is complete.
Sand Pumping Creates Display, Pumping 24/7
Sand pumps around the clock, but not continuously. Inclement weather, rough seas and mechanical issues can halt operations. In early September as Hurricane Dorian was churning off the east coast, dredging was halted and both vessels took refuge in New York Harbor until marine conditions improved. (For a time, Dorian generated swells of 10-12 feet; seas greater than four feet hinders dredging operations.)
It can take months from the time a dredging contract is signed until sand begins flowing: due to insurance and bonding, assembling a crew, loading provisions, travel to the work site (often hundreds of miles), laying steel pipes on the ocean floor and the beach, and setting up the work site itself.
Dredges working on a project of this magnitude are not ordinary size vessels. In fact, luxury notwithstanding, you can find most anything on these huge vessels found on a cruise ship, such as sleeping areas, full kitchen facilities, medical unit and office space. These dredges weigh hundreds of tons and are equipped with extremely powerful engines and pumps needed to transport the sand to shore.
When it all comes together, there’s a lot of action. During a recent site visit by project manager Robert Vohden, along with New York District engineers and Public Affairs staff, sand was pumping on shore as a pile driver was pounding poles for walkways, sections of pipe were being moved, and bulldozers spreading sand to the proper contour of the beach. When complete, people and property behind the beach will have reduced risk of flooding and damage from severe storms and tidal surges.