Posted on January 19, 2017
By Peregrine Frissell, greenwich time
When Greenwich announced in December plans to dredge the silt-clogged pond in Binney Park, residents familiar with the pond’s condition wondered whether the town would also take steps to slow the flow of silt into it so it doesn’t just fill back up again.
To that end, they also wondered what had happened to money budgeted to build silt traps at the pond.
The town set aside $1.2 million for the 2015-16 fiscal year to design and construct sediment traps. Officials said the traps would reduce the need for dredging in the future.
To date no traps have been installed.
Department of Public Works Commissioner Amy Siebert said recently the funds are still in place, but the timing and coordination of the project have changed.
”Originally, we anticipated constructing the traps first, with dredging to be done separately as a second project,” Siebert said. “Discussions with regulatory agencies indicated that the preferred approach was to execute the construction and dredging together.”
The town has used the funds in hand to complete the design of both the sediment traps and the dredging as a combined project, Siebert said.
“Additional funds are needed to execute the dredging, which is to be done in conjunction with the (trap) construction project,” she said.
The Department of Public Works is requesting $3.5 million in the 2017-18 budget to dredge the pond and construct and install the silt traps in one move.
“Our goal, although one can never be sure just how the permit chips will fall, is that we’d be able to get going on this work in Summer 2017, provided the capital budget request is passed,” Siebert said.
As part of the permitting process, the material to be removed will have to be tested before dredging can begin.
The silt, projected to be about 9,500 cubic yards, could contain contaminants that require special care in disposal.
Tests of the sediment on the floor of the pond were conducted back in June 2015 by the Los Angeles-based engineering firm AECOM. Five samples were taken from different locations in the pond, and PCBs were found in three of them.
In one of the samples, the level of PCBs was higher than 1 milligram per kilogram of soil, the level at which disposal options become restrictive. The report said the silt at that level would not be classified as hazardous waste, but would not be used, for example, as on-site fill.
The report also said the pond has been affected by its location, downstream of I-95 and surrounded by local, heavily trafficked roads.
“Based on the results of this investigation, it appears that the sediment has been impacted by constituents associated with petroleum releases,” the report reads. “Binney Park pond is located downstream of Interstate 95 and storm water run-off from major roadways may contain petroleum-related compounds. In addition, vehicle releases of petroleum products along nearby highways or surface roads may travel through storm water conduits and be released to the pond. … In general, the environmental characteristics of the sediments found in Binney Park Pond are consistent with the environmental quality of sediments found in similar urban/suburban settings.”
Despite the report, new tests will have to be performed before dredging takes place. The results of such tests are only good for one year, said Patricia Sesto, director of the town’s Inland Wetlands and Watercourses Agency.
The town previously commissioned a test to determine where the silt settling in the pond is coming from. The results showed that the lion’s share comes down Cider Mill Brook, portions of which cross over into Stamford.
The town has had talks with Stamford officials, urging them to rein in any erosion on their side of the border, Siebert said. She said talks will continue and improvements will hopefully be made as municipal budgets on either side of the border allow.
Source: greenwich time
