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TCTU SPONSOR
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| Vermillion River |
10/13/2009 |
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TCTU leadership had expressed an interest in trying some alternative stream habitat techniques that did not incorporate structures or riprap, so I helped put together a design that would rely more on establishing better vegetation, along with some shaping of streambanks to allow for more stability during and after vegetation establishment. I wanted to try a suite of approaches on the site to assess not only the benefits to the stream of various practices, but also the cost/benefit. Overall, the goal is to establish deep rooted vegetation that can stabilize streambanks, so that over time the stream can narrow and deepen. Undercut banks will eventually form as well, and the resulting channel will have better trout habitat. Half of the project site will be planted in native prairie grasses, sedges, and wildflowers, the other half of the project will have trees and shrubs planted. We will assess the relative benefits of both types of streamside vegeation over time for both streambank stability and fish utilization. Native prairie plants or trees will have deeper roots than the previous plant cover at the site, a near monoculture of reed canary grass. Assessment of ongoing maintenance needs to sustain native vegetation in both cover types will also be done.
All bank treatments were intended to allow vegetation to establish nearer to the waterline, so that roots can protect the entire streambank, and to reduce the slope of the banks to provide better stability. On the minimal end of the spectrum of treatments, we simply sloped the streambank and installed an erosion blanket at the toe. A more involved approach at other locations was to install encapsulated soil lifts at gradual slope, which will likely provide better initial stability than sloping. At other locations, encapsulated soil lifts were placed atop either brush-sized or large woody material. The woody material is intended to provide not only better initial stability to the streambank, but also to provide more instant cover for fish. At some locations, encapsulated soil lifts were built to narrow the stream in areas where naturally filling was already occurring.
Photos of the project
Blog Comment From: Jeff Hastings
Nice job of documenting a project well done!! Very impressive!
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