Town to Launch Stormwater Runoff Remediation at Mill Pond

The Town of Brookhaven in November will launch a stormwater mitigation project designed to regulate how rainfall affects Setauket's Mill Pond, supported in part by the New York State Department of Environmental Conservation.

A spokeswoman for the DEC said Wednesday said about 20 leeching basins will be installed around the pond, which will control approximately 90 percent of precipitation during an average rainfall. Leeching basins are concrete containers that are slotted on the sides to allow accumulated stormwater to seep into the ground.

"Reducing stormwater into Mill Pond will reduce the sediments, nutrients, pathogens, litter, and other pollutants that are washed into the pond during rain events, and subsequently, into Conscience Bay," Aphrodite Montalvo, citizen participation specialist for the DEC, told Patch in an email.

Montalvo said the DEC has awarded a $99,000 grant to the Town of Brookhaven Highway Department for the project via the Clean Water/Clean Air Bond Act. The town will match the grant, bringing the total fund for the project to $198,000.

On Friday the project garnered praise from Robert Reuter, vice president of the Frank Melville Memorial Foundation, the private organization which owns the bottom of the pond and the surrounding parkland.

"We're very excited to see that project going on," Reuter said.

Related to the stormwater project, the Frank Melville Memorial Foundation is planning a dredging project that is expected to help return the pond to its original depth and preserve the habitat of the species that live there.

Reuter said Friday that the depth of Mill Pond – originally a man-made pond dating back to colonial times, when it was used to make ice – was about eight and a half feet at its deepest point. The stormwater runoff that the DEC is trying to mitigate has contributed to the accumulation of sediment material in the pond. Built up over the years, that sedimentation has reduced the pond's depth to "almost nothing" in some places, Reuter said, and in other places just a few feet deep. Where it is most shallow, the plant species that normally grow vertically at greater depths have been growing horizontally across the top of the water.

"It's not a dangerous, invasive plant, but it usually grows at a greater depth," Reuter said. "That's what gives it the appearance of being kind of scum-covered, especially on the south end."

One of the obstacles in the way of the dredging project has been the DEC's requirement that the source of the sedimentation be resolved. Reuter said the drainage work being done along Main Street as well as the new stormwater remediation project have helped clear that roadblock, although there are still several other steps to be taken before dredging can begin.

Mill Pond feeds into Conscience Bay, where much of the bay's shoreline is the territory of the Incorporated Village of Old Field. Because village residents are frequently concerned about the environmental vitality of Conscience Bay, mayor Michael Levine praised both of the projects as worthy ideas.

"All of these projects are absolutely great for the health of Conscience Bay," he said, "and if the Town of Brookhaven would like to come into the village and install some more of these leeching basins, I personally will welcome the town with open arms and a big hug."

Editor's note: This story has been updated from a previous version which said the project was a state DEC project. It is in fact a Town of Brookhaven project.