The offshore disposal site for dredge material off New London Harbor would remain open after its current planned closing date this December and would be expanded, under a proposal announced Wednesday by the Environmental Protection Agency.

The EPA said the New London site, located between the mouth of the Thames River and the southwestern end of Fishers Island, would be expanded to receive up to 27 million cubic yards of dredge material.

The eastern half of current site, which totals about 1 square mile, is at capacity, but the western half would remain open and two adjacent areas would be added, bringing the total of the new open area to 1.5 square miles, said Mel Cote, chief of the surface water branch of the EPA's New England office.

The total capacity of the new site exceeds the expected amount of sand and silt that will need to be dredge from harbors, channels and marinas over the next 30 years — about 22.6 million cubic yards — but the excess capacity will provide the eastern sound with a disposal site for decades and avoid the lengthy process of finding a new one, Cote said.

 The proposal, along with a draft Supplemental Environmental Impact Statement, was released Wednesday for public comment.

“We’re pleased the EPA recognizes the need to maintain the option for open water disposal of dredge materials,” said Dennis Schain, spokesman for the state Department of Energy and Environmental Protection, which had advocated for continued availability of disposal sites.

“Connecticut’s ports, harbors and marinas depend on periodic dredging, and it’s not always practical to find beneficial reuses for those materials, even though that is a top priority,” he said.

Environmental groups had been advocating for an end to offshore disposal of dredge materials in the Sound, arguing that the material could be reused for beach and marsh rebuilding projects, among other onshore uses.

The EPA said that along with keeping the New London site open, it also is proposing to set restrictions on its use so that as much material gets reused onshore as possible.

A second disposal site in eastern Long Island Sound — at Cornfield Shoals off Old Saybrook — would be closed in December to most types of dredge materials, under the EPA’s proposal.

Cote said that under the proposal, the Cornfield Shoals site would only be available for small private projects.

There are two additional open disposal sites in the central and western Sound.

The EPA said it will receive comments on the proposal through June 27.

Four public hearings also will take place: two on Long Island on May 25 and two in Groton on May 26.

Cote said that, depending on the content of public comment, the size and boundaries of the New London site could be adjusted or the proposal for the Cornfield Shoals site reconsidered.

A possible site in Niantic Bay is not under consideration, but that also could be reconsidered, Cote said.

The New London site, however, "has been demonstrated to be the best containment site in the eastern Long Island Sound," Cote said. "Material that's put there stays put."

In a news release, the agency said it determined that keeping the New London site was necessary “because there are currently no disposal sites designated for long-term use in the eastern Long Island Sound region, the dredging needs exceed the available capacity at existing sites, and the regulations require EPA designation for any long-term dredged material disposal site.”

The EPA said that while it is committed to developing and promoting the alternatives to open-water disposal, it is still necessary for some projects.

Periodic dredging of harbors and channels is essential for ensuring safe navigation and facilitating marine commerce and recreation, the EPA said.

The proposal would make the disposal site available for future projects requiring disposal.

Authorization to dispose at the site requires project-specific approvals and must meet stringent requirements, the EPA said.

Dredge material that is found to be toxic cannot be dumped in the Sound.

After the public comment period concludes, the EPA will issue a final decision this summer.

j.benson@theday.com

 More information:

The EPA's proposal for the eatern Long Island Sound dredge disposal site can be found at: http://1.usa.gov/1NBeHpe.

Public hearings on the poposal will take place from 1 to 3 p.m. May 26 and from 5 to 7 p.m. May 26 at the Avery Point campus of the University of Connecticut, Room 308 of the Academic Building.

Comments can be emailed to ELIS@epa.gov, or mailed to Jean Brochi, USEPA, 5 Post Office Square, Suite 100, Mail Code: OEP06-1, Boston, MA 02109.