A long-awaited Army Corps of Engineers plan for handling sediment from Long Island Sound dredging projects would continue to use four open-water disposal sites, but seek ways to divert larger-grain sands to beach replenishment projects, and use suitable fine grains for wetland and environmental restoration.
The Corps manages 52 navigation projects along the 105-mile sound, and has long been under pressure from environmental, fishing and other interests to rely less on dropping sediment on the disposal sites.
An avowed goal of the draft dredge materials management plan (DMMR) is "reducing or eliminating the disposal of dredged material in Long Island Sound." But that could lead to more beneficial use of sediment – and work for dredging and workboat companies – if future funding comes through.
“Collectively, these federal, state, local and private dredging activities total about 53 million cubic yards over a 30-year period,” the report notes. “However, only a portion of these are likely to be dredged in that period, as future actions are contingent on federal and non-federal budget decisions.”
Most sand dredged in and around the sound already goes to beach replenishment projects, “and that practice is expected to grow in the future,” according to the report. In the wake of hurricane Sandy in October 2012, the federal government stepped up spending for beach rebuilding and flood control projects to protect ocean and bayside towns from future storm surges.
Dredged materials that do not pass toxicity tests for pollution will continue to be handled by treatment disposal in containment sites – practices that have grown since the 1990s, when the Corps and U.S. Environmental Protection Agency had to deal with polluted sediment from deepening projects in the New York-New Jersey harbor complex.
Finer grain materials that do pass the tests could still be placed on the open-water disposal sites, but the DMMP looks to use hem more for beneficial uses – such as capping former disposal areas to confine pollutants, or using them to restore coastal wetlands.
Dredged materials from New York Harbor were used in 2012-2013 for restoring islands in New York’s Jamaica Bay, where accelerated erosion threatens to destroy much of the wetlands by 2025. Instead of being treated as a disposal problem, wildlife and coastal conservation agencies are looking to dredged sediments as a means to build up wetlands threatened by sea level rise, which is picking up its pace along the mid-Atlantic coast.