Even the trout are seeking relief from summer’s heat

CORNWALL — Every year, the state Department of Energy and Environmental Protection (DEEP) Inland Fisheries Division stocks the Housatonic River with 18,000 rainbow and brown trout. And every year, hundreds die due to heat stress in the warmest summer months, when the river runs slower and shallower. 

The remedy is called a thermal refuge or, put more simply, a deep pool where cool water can collect. 

Fishermen know this is where they will find trout, bass and other large game fish.

Trout Unlimited (TU) wants to install a refuge just upstream of the Covered Bridge in West Cornwall, where Mill Brook sends fish — and much colder water — into the river. The plan is to create a deep pool where cold water can collect. Placement is crucial, and engineering will be needed to find or configure a spot where natural scouring will occur, so the pool will not need to be scooped out again.

The goal is not to provide a better place to fish, but to protect the trout and, by extension, the health of the river, according to a contingent of TU and Department of Energy and Environmental (DEEP) Fisheries Division representatives. They gathered July 15 with local selectmen Gordon Ridgway and Richard Bramley, and business owner Ian Ingersoll, along the bridge that spans Mill Brook at its confluence with the river. Ingersoll has long advocated for the river and helped create the tiny parks by the Covered Bridge.

Those parks, which include trees planted to help cool the river, were installed in the wake of the 2011 replacement of the  old Mill Brook span, which had been destroyed by Hurricane Irene.

The construction included a small rock jetty to protect the bridge from river flooding and a fish ladder to help trout retreat to the brook.

Some refuges occur naturally. There is quite a large one a bit upstream of Mill Brook that also serves as a ready water supply for firefighters. Ridgway and Ingersoll said protecting that is a priority.

Tracy Brown, the Northeastern Restoration Coordinator for Trout Unlimited, said a study is needed first to determine how deep the existing pools are and the potential impacts of changing rock formations. 

“It’s an important tool,” she said. “We need to avoid scouring the rest of the river.”

Jim Fedorich, of the Northwest Connecticut Trout Unlimited chapter, said one possible approach is to straighten and extend the jetty, to widen the current of cold water that hugs the east (or brook) side of the river. 

An experienced boater who has spent a lot of time on the Housatonic, Fedorich said most boaters stay toward the more natural channel toward the western shore. The jetty would not be a hindrance, and boaters would travel over refuge pools without noticing.

The next step is to raise funding, with a rough estimate of $50,000. That includes about $10,000 for the study. Costs will be driven by ease of access to the dig site and whether or not needed materials can be found on site. 

Funding sources may include Trout Unlimited money, a grant from the Housatonic Fly-Fisherman’s Association and possibly local donors and the GE PCB cleanup fund.

This all leaves the project in a very preliminary phase.

Michael Humphries, of the DEEP, who was joined by colleague Don Mysling, said a trout refuge there would be the most important one in the area, followed by one at the convergence of Furnace Brook and the Housatonic in Cornwall Bridge. 

The difference in water temperature there is not so pronounced, since the brook, which begins in the Mohawk Mountain area, is not as shaded as Mill Brook and does not take as steep a downhill course.

There, Humphries said, a refuge 30 to 40 feet long and about 5 feet deep can hold up to 500 trout seeking to cool off.

An elaborate fishway was installed by the Housatonic Valley Association just upstream in the brook last September. It allows fish to make their way back into the cooler brook to spawn. Humphries is involved in a follow-up study to evaluate its operation. Falling leaves clogged traps last year, preventing a determination. New approaches are being devised.