The beep, beep, beep of an excavator last week was a clear sign restoration work had begun on the Norwalk River at Schenck’s Island, bringing to fruition a two-year effort to improve fish habitat.

The work being shepherded by the Mianus chapter of Trout Unlimited is likely to bring about some clearly identifiable changes, not only in the physical appearance of the river but in what is in it and above it.

There almost certainly will be more trout, but while Wilton probably won’t see any eagles — the tree canopy is too dense — “you could get osprey here,” Brian Cowden told The Bulletin last week.

He and Lance Bigelow are co-owners of Trout Scapes River Restoration, which is doing the in-river work — digging out deep pools of water and using the material excavated to create point bars, also known as gravel bars, as well as placing large boulders strategically along a half-mile stretch within Schenck’s Island.

“We’re defining the thalweg,” Cowden said, a German word meaning the deepest part of the river. A deep channel is essential to a healthy river during periods of low flow, he explained.

Conversely, during rainstorms, stormwater flows into the river from roads and lawns introducing warm water, sediment and pollution. Building up the banks adds protection.

An excavator from Trout Scapes River Restoration digs a channel in the Norwalk River as part of a river restoration project headed by the Mianus chapter of Trout Unlimited.

Media: Jeanette Ross

The new point bars will be a boon to anglers, who can stand on them and cast to the deeper pools where larger fish tend to congregate.

“We’re also making insect habitat,” he added, pointing to the riffles. “The cobbles are big enough so the water ripples,” thus oxygenating it.

They are also introducing some tree limbs in the water. “You want woody recruitment,” he said, but not a logjam.

“Fish and insects like wood in the river. Certain insects only hatch on wood,” he added.

All this is essential for insects which provide food for bats and birds as well as fish.

Excavation

The Norwalk River is “fairly typical of East Coast rivers,” Cowden said. It’s in a densely populated area — “the longest lived-in area of the country” — with many old dams and stormwater systems.

“Had man not done anything here, this would not have been necessary,” Cowden said.

“But it’s restorable,” he said. “As obsolete dams are removed, you will see more fish,” perhaps even striped bass and river herring, ocean fish that could come here to spawn.

The heavy work was being done with a medium-sized track excavator maneuvered by cowboy-hat-wearing operator named Ron Weekes, who came east from Trout Scapes’ home base in Montana. He has more than 30 years working in rivers, Cowden said.

The excavator, as big as it is, weighs less per square inch on the bottom of a stream than a person standing there, Cowden said. It is brought out of the river each night and refueled on land.

As it scratched and clawed the compacted river bottom, Cowden said no material, other than some boulders, are being added. The boulders are the by-product of development work done in Wilton over the past several decades and have been stored at the transfer station.

The gravel Weekes is moving around will be beneficial to trout that like to build their nests — called redds — in them. The fish will make depressions in the gravel, lay their eggs and then leave, with the eggs hatching in the spring. Unlike salmon, trout can spawn and live for several years.

When the in-river work is done, which is expected to be completed before the end of this week, the banks will be reseeded with a native riparian seed mix. Volunteers from Trout Unlimited will also be placing the limbs and root wads of dead ash trees, cut down at Schenck’s Island, along the banks to further enhance fish habitat.