Trout Unlimited NEW JERSEY STATE COUNCIL

Trout Unlimited NEW JERSEY STATE COUNCIL


August 21, 2013

Insect life in restored river channels in the Musky

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An underwater close up of cased caddis covering a rock in a restored site on the Musky

When TU takes on a river channel restoration project, we do so with the utmost care for the river’s health.  We work on channels that have been degraded and hold excess sediment due to past land use practices.  These include farming too closely to the stream, channelization, removal of stream side vegetation that leads to eroding banks, or when a dam is removed and the upstream impoundment requires channel restoration.  Working closely with our partners at the Musconetcong Watershed Association and using a grant from the Natural Resources Conservation Service, we are studying the effects of these projects over a three year time frame that began earlier this year.  We will be studying the sites using baseline data and then post restoration data gleaned over the 3 year period.  In our study, insects (benthic macro invertebrates), pH, dissolved oxygen, temperature, and turbidity will be tested amongst other water quality indicators.  Our goal is to demonstrate the effectiveness of these projects for the overall health of the river.

By manipulating the bed of the river with a wide track machine, we remove excess sediment that has covered up insect life in the channel over decades and this flush of sediment is what sets up the habitat for greatly increased insect life.  Just as importantly as removing excess sediment is making the natural processes of the river function properly again so that the channel no longer fills itself in with sediment.  This creates a “biological lift” to greatly increase the health of the river and it impacts the river over more than just the restored stretch as our studies are beginning to demonstrate.  Stay tuned for published details of our studies in coming months.

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    This underwater photo is pre-restoration of the same site. Note the sediment choking out aquatic insect life.
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    This species of stonefly is now very common in the faster water sections of our restored channels.
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    We are also seeing an increase in clinging mayfly species which prefer low sediment and more cobbles which is encouraging.
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    The bottom is paved in caddis and when you turn over these cobbles, you find lots of mayflies and stoneflies.
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    Covered with caddis!
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    A conglomeration of aquatic insects.