Rebuilding a trout highway near Furnace Brook in Cornwall

CORNWALL — Passersby on Route 4 in Cornwall Bridge no doubt wondered why a fire truck was parked on a bridge just east of the Route 7 intersection on the afternoon of Sept. 11. Furnace Brook passes below, and they might have suspected some sort of rescue.

They would have been correct, in a way.

It was a rescue of trout that have been unable to migrate upstream into the brook from the Housatonic River to spawn in early fall or simply cool off in the summer. 

Furnace Brook flows from Coltsfoot Valley to Cornwall Bridge, mostly along the Route 4/Furnace Brook Road corridor. It drains a 13.3-square-mile watershed. About 1,000 feet from its confluence with the Housatonic, it passes under Route 4 through a 120-foot box culvert. Unimpeded by rocks or winding banks, the water velocity is high in the culvert. Few trout can swim against the current.

Michael Jastremski, Water Protection Director for the Cornwall Bridge-based Housatonic Valley Association (HVA), said the issue was addressed in the early 1990s with the installation of wooden baffles inside a low stone wall constructed to one side of the culvert as a fishway. 

“The internal flow controls were damaged by a major flood not long after that,” Jastremski said. “It was never fixed.”

With funding from the Natural Resource Damages Fund, HVA bought Alaskan Steeppass aluminum baffle systems that now line the fishway to create a durable, efficient way to slow water speed. The 450-pound units were hauled over the side of the Route 4 overpass last week — attracting quite a bit of attention along the way.

But most of the work is being done out of sight, with access to the brook and from the yard of Joanne Wojtusiak, who Jastremski said has been very gracious. The project was expected to take about two weeks.

Partners in the effort are the Inland Fisheries Division of the Connecticut Department of Energy and Environmental Protection and the Housatonic Fly-Fisherman’s Association.

Engineering was done by Princeton Hydro LLC.

“It will be very exciting to see large numbers of trout heading upstream for the first time in 20 years,” Jastremski said. “They should start heading upstream to spawn toward the end of the month, and that will last for four to six weeks.”

Activity will be monitored. One method — not harmful to the fish — is to send an electrical current through the water to temporarily stun them. The fish are then netted, counted, tagged in some cases and released.