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    Thursday, June 08, 2023

    EPA study finds New London dredge disposal site ideal

    New London - The current dredge disposal site about 3.5 miles south of New London Harbor is the most suitable location for handling sediments that clog navigation channels, harbors and marinas, based on a physical oceanographic analysis of 11 sites in eastern Long Island Sound.

    Results of the analysis, conducted for the Environmental Protection Agency by Frank Bohlen and Grant McCardell of the University of Connecticut Marine Sciences Department, were presented Tuesday during a meeting at Fort Trumbull State Park.

    Among the 30 attendees were several marina owners who emphasized their need to have convenient sites open for depositing dredge material.

    Bohlen, professor emeritus of marine sciences, said that based on tidal action, storm surge, fresh water inflow from rivers, current action and other factors, fine-grain sand deposited at the New London site stays in place more than in the other sites evaluated. He provided a detailed explanation of how the study reached its conclusions.

    "New London was the only site in eastern Long Island Sound with a maximum bottom stress below .75," he said, referring to the number for the optimal measure of stress found to keep sediments relatively immobile.

    The EPA, in conjunction with the Army Corps of Engineers, is evaluating the environmental impact of designating one or more new disposal sites in the eastern sound after the New London site and Cornfield Shoals, off Old Saybrook, close as scheduled in 2016. The analysis includes consideration of continuing to use either of these two sites, as well as four other areas: Clinton Harbor and the nearby Six Mile Reef; an area off Niantic Bay; and another off Orient Point, Long Island. The analysis by Bohlen and McCardell included five additional sites. The Cornfield Shoals site, he found, had the highest propensity for sediment deposited there to move elsewhere.

    Christian McGugan of Grenmor Marina and Marine Contracting in Mystic said he is concerned that New York State could object to the redesignation of the New London site because of its proximity to Fishers Island, or to any other site that is chosen. The objection could be brought under the federal Coastal Zone Management Act.

    "This could set off an appeal process that no small marina operator could bear," he said. He said alternatives being studied to handle dredge spoils, such as using uncontaminated material to rebuild shoreline areas and marshes, are impractical, and having to transport material to the central Long Island Sound dredge site near New Haven would double the cost of dredge projects.

    Jean Brochi, project manager for the Ocean and Coastal Protection Unit of EPA Region 1, said other areas that will be studied before a final decision on a site include impacts on sea floor habitats and capacity of various sites. About 13.5 million cubic yards of sediment is expected to be dredged from the eastern sound through 2028.

    A draft version of the environmental analysis, called an environmental impact statement, is scheduled to be released in the spring, she said. A final version, including a designation of one or more disposal sites or a "no action" alternative in which no area would be designated, is slated for December 2016.


    Twitter: @BensonJudy

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