Conservation Commission grants order for Lowell sewer-separation outfall at 639 Aiken Ave

The Lowell Conservation Commission on Feb. 26 approved a City of Lowell standard Order of Conditions for a notice of intent by the Lowell Regional Wastewater Utility to install a mainline drain conduit and a new outfall near 639 Aiken Avenue to divert large inflow sources from Humphreys Brook and the Billings Street wetland to the Merrimack River (DEP 2060840).

The project is part of an eight-year sewer-separation program the utility said is mandated by the U.S. Environmental Protection Agency and the Massachusetts Department of Environmental Protection under a consent decree. "This is an eight-year project mandated by the EPA and MassDEP in our consent decree," said Evan Walsh, engineering manager at the Lowell Regional Wastewater Utility. Walsh said the work is intended primarily to reduce combined sewer overflows; "additional benefits will include less street flooding and sewer backups into people's properties."

The approved first phase installs a large-diameter conduit that the utility described as ranging from a 5-by-8-foot box culvert to a 36-inch pipe and will run from the outfall near Bunker Hill up Bunker Hill Avenue and along several streets including Barker and Billings before reaching Humphreys. The commission record shows permanent impacts to resource areas at the Bunker Hill outfall and riverfront: commissioners confirmed an impact of 852 square feet at the outfall. The utility said most disturbance will be at the outfall location and that other work in the commission's jurisdiction will be within the 25-foot riverfront area but outside wetland limits.

Walsh outlined construction and environmental controls for the outfall installation: a cofferdam will surround the work area; dewatering will be routed through a filter sock and either returned to the river (subject to water-quality checks), discharged to ground, or routed into a nearby sewer manhole for treatment at the plant. A compost filter sock will be placed to the ordinary high water line. The utility said it will remove topsoil and invasive plants from disturbed areas and that proposed work will result in a net gain for flood storage.

At Humphreys Brook, the project will replace an existing, deteriorated trash rack and will perform machine work from the street and hand work in the wetland inlet; the utility stated that no heavy equipment will enter the wetland there. The project team said it has coordinated with MassDOT, the U.S. Army Corps of Engineers, EPA, MassDEP, FEMA and the Department of Conservation and Recreation.

Commissioners asked about dewatering locations and monitoring. Walsh said dewatering near the outfall would enter the combined sewer and go to the treatment plant; dewatering near Billings or Humphreys would route to sewer manholes and be treated. He also said a resident engineer from CDM Smith will be on site to ensure daily inspection logs of hydraulic controls are kept by the contractor or the RE.

The utility said the first phase is scheduled to finish in 2027 with final paving in 2028; construction is expected to start in late summer or early fall pending permanent approvals and an anticipated contract award after June 30. The project is expected to be funded by the State Revolving Fund (SRF).

The commission closed the public hearing with no public comments and voted to issue the City of Lowell standard Order of Conditions. The motion to grant the order was made by Commissioner Downs and seconded by Commissioner Laput; the vote was recorded as in favor.