Trout Unlimited Restoring River Channels to Improve Trout Habitat Along the Musky

Posted on by Brian Cowden, Trout Unlimited

A trout fisherman casts his fly rod in a section of the Musconetcong River in Warren County Trout Unlimited restored. Photo By Meghan Jambor

An important and often misunderstood part of Trout Unlimited’s work in New Jersey is its stream channel restoration projects.

Brian Cowden is the Musconetcong Home Rivers Initiative Coordinator of Trout Unlimited. Courtesy of Brian Cowden

More obvious, perhaps, is the impact of obsolete dam removal and the planting of native trees and shrubs can have to improve and restore fish and wildlife in a river ecosystem. In fact, all three techniques are employed by Trout Unlimited and our partners to return the 47-mile Musconetcong River, which flows from Lake Hopatcong to the Delaware River, to a place where both trout thrive and fishermen, kayakers and hikers recreate.

When poor aquatic habitat is restored, the insects that fuel the river’s ecosystem rebound to greater abundance then most anywhere else on that same river, and the anglers follow suit.

Those stretches that Trout Unlimited and our partners have restored are now some of the most popular fishing locations for trout in the state. Fly fishing anglers flock to these newly restored reaches because the insects their flies imitate are in such abundance, but spin anglers also love these areas for the abundance of trout living in them. Often these fish move in quickly after restoration and grow larger than those in surrounding water due to the food supplies that take up residence in the restored channels.

Trout Unlimited’s role

Trout Unlimited focuses its in-channel restoration work on stretches of river that were severely impacted by man’s interference by such past practices as channelizing a river to prevent flooding or when we built too many homes and businesses in or adjacent to our floodplains.

When the latter occurs, rain waters flash off all of the roofs and roadways and enter our streams and rivers in greater than normal velocities, carrying in excess sediment and actually widening banks while depositing sediment in the stream bottom.

Over time, our streams and rivers become overly widened and clogged with sediment in these reaches, which in turn reduces aquatic habitat for the insects and the fish that depend on them as food. Once we have these conditions, aquatic life deteriorates over time and trout and other animals including stream-side birds, wood turtles, otters, and many others suffer as the food chain breaks down.

One stream channel restoration project that Trout Unlimited took on in the winter of 2012 was on two adjoining private properties over a nearly one-mile stretch of the Musconetcong River in lower Washington Township in Warren County. The river’s channel had been altered and moved onto adjacent farm lands prior to 1930 and the result was a widened, shallow channel with few cobbles showing and no riffles, runs or pool habitat. Although the downstream property’s owners allowed public fishing access, you would very seldom encounter any anglers, even on stocking days.

Today, that section sees anglers in strong numbers daily and the landowners have enjoyed sharing their river with others. In fact, both husband and wife have taken up trout fishing themselves and enjoy warm evenings catching trout in their own backyard.

The process

Degraded channels are restored using a somewhat invasive technique that involves a large track machine with a hydraulic bucket, the same equipment used to dig a foundation.

A track machine operator tamps down on a restored point bar along the Musconetcong River in Finesville. Courtesy of Brian Cowden

Trout Unlimited hires a design and build firm to perform this work with a machine operator that only works in river channels. That expertise in only working in river restoration is critical to the overall success of the project.

The track machine operator, implementing a design plan permitted by New Jersey Department of Environmental Protection’s Division of Land Use, moves cobbles and sediment in the river’s bottom to form riffles, runs and pools. Large boulders are added to stabilize any new pool, riffles or run habitats that we restore.

The restoration plans in these degraded channels includes narrowing them back to their pre-degraded widths to allow better sediment transportation in all flows.

When river channels fill with sediment during low flow conditions, the channels become increasingly shallower over time. When that happens and we have a flood, the river widens its banks, further slowing down sediment transportation and adding that sediment to the river’s bottom which continues the downward spiral to our aquatic habitat.

Pool habitat is built and maintained by the installation of boulders made into an upstream facing weir which directs the river’s flow and maintains scouring in the pool so that sediment won’t simply fill up our restored pools in a few short years or less. This pool habitat ensures cooler water during warm summer months that trout need for survival while keeping them safe from overhead predators like bald eagles, great blue herons and ospreys. Trout often spawn near the tails of pools and in riffles, as well.

The payoff

The end result of restoring degraded river channels is a tremendous biological uplift. Within the first year, we find that the aquatic insect populations in our restored waters are unlike the surrounding river up or downstream in both increased numbers and diversity, proof that removing excess sediment leads to greatly increased habitat for insects and the fish that feed on them, including our native brook trout as well as both wild brown and rainbow trout and state-stocked trout of all three species.

Trout Unlimited and our partners monitor the success of these projects by taking baseline water quality samples and annual sampling for three to five years post restoration. Our sampling has shown that we are now seeing some “zero-tolerance species” of stoneflies which are a key indicator species of clean, cold water.

Scott, a Trout Unlimited intern, shows off a caddis fly, an indicator of clean water, along the Musconetcong River near a Trout Unlimited restoration site. Photo by Meghan Jambor

One such insect, the 3-inch-long giant black stonefly (Pteronarcys dorsata) had never before been documented in the Musconetcong River, but was identified in some of the most pristine headwater tributaries in that watershed.

Following the stream channel restoration project Trout Unlimited completed during the winter of 2012, that giant stonefly is now found in the main river in our restored waters.

And trout are on the prowl for that big meal….

Trout Unlimited is North America’s leading coldwater conservation organization, working to protect and restore our native trout and salmon fisheries.  New Jersey is home to native brook trout, the state’s fish, and the Musconetcong River and its watershed remains home to this beautiful species. Brian Cowden is coordinator for TU’s Musconetcong Home Rivers Initiative and lives in Flanders, NJ.

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