New Canaan commission approves two pond maintenance dredging permits

The New Canaan Inland Wetlands Commission on Nov. 17 unanimously approved two applications to hydraulically dredge private ponds as routine maintenance.

Matt Voigt of New England Aquatic Services told the commission the Onoke Ridge pond at 1541 Owen Oak has filled with leaves and detritus and will be cleaned using a trailer-mounted pump and a 5-inch suction nozzle. "We have, I think about 300, 350 cubic yards of material wet that we're estimating in the pond itself," Voigt said, adding that material should dewater to about 100–150 cubic yards for off-site removal. He estimated the dredging would take about two weeks, weather permitting, and said the method leaves much of the pond water in place so wildlife can use untreated areas as refuge.

For the larger pond on Indian Rock Road, Voigt said the contractor will use a floating, cable-driven dredge and will stage dewatering tubes on-site. Because that pond is part of a stream system, he said turbidity curtains and lined dewatering areas with silt fences will be used to limit downstream impacts; the project is expected to take three to four weeks, followed by several months of dewatering prior to hauling material off-site.

Director of Inland Wetlands Kathleen Holland recommended a standard special condition for both permits requiring an inspection by the consultant and submission of a final compliance report to staff after dredged sediment is removed and the dewatering area has been stabilized. Holland told the commission that because the work is confined to the pond basin and does not disturb shorelines, the proposals qualify as pond maintenance.

Commissioners questioned equipment access and whether the work would affect nearby dams. Voigt said the equipment pulled behind a pickup is light, that larger dump trucks will remove the dewatered material, and that his crews will avoid working near any dam infrastructure.

Both permits were approved by voice vote with no dissents. The commission recorded the approvals as unanimous and attached the consultant-inspection and final-compliance-report requirement to each permit.

The commission noted the projects are maintenance work initiated by private homeowners and that staff will coordinate site inspections during and after implementation to verify compliance with erosion-control and restoration measures.