For nearly 30 years, when Suffolk County dredged waterways on the East End, much of the dredge spoil was deposited in a seven-acre area at Indian Island County Park in Riverhead.
And officials say that when it rained, contaminants from that dredge spoil leached into nearby Terry Creek, a tributary of Peconic Bay.
The dumping of dredge spoil began in 1947 and continued until 1975, according to County Legislator Ed Romaine (R-Center Moriches).
Now, Mr. Romaine says, the county has a plan to remove some 25,000 cubic yards of dredge spoil and cut a new channel to the creek.
“This will reduce the amount of contaminants that flow into the bay from this dredge spoil site and recreate a marsh system that was here previously by connecting this area to Terry Creek,” Mr. Romaine said.
“This also will potentially help to eliminate an existing mosquito problem that we have here,” he added, “because the water is not free-flowing. When you open it up to the creek, you have a tidal flow, and it’s hard for mosquitoes to breed in water that’s flowing.”
The spoil, piped into the site over the years, is now so thick that water can’t seep through it and the area sometimes looks like a pond, according to county parks department employee Nick Gibbons.
Mr. Romaine said it’s not known what contaminants the spoil contains. He said it probably contains phosphates and nitrogen from fertilizer, and contamination from gasoline and agricultural chemicals, but will have to be tested to determine where it should be taken once it’s removed from the site.
Removal would involve scooping up the spoil and carting it to an out of town landfill approved for such materials, then breaking down a dike surrounding the dredge site so that a new channel can be created connecting it to the creek, Mr. Gibbons said. Some trees would have to be removed and a culvert installed so a walking path could be created on the site, Mr. Romaine said.
The new cut will probably be about 20 feet wide and about a quarter-mile long, he said.
Funding for the project will come from a $900,000 state Environmental Facilities Corporation grant and the county’s quarter-center sales tax, which is used for environmental projects, Mr. Romaine said. The total cost will be about $1.2 million, he said.
The project still needs approval from the state Department of Environmental Conservation and will then have to be put out to bid, so the exact starting time isn’t certain, Mr. Romaine said. He said he was hoping work could begin this year.