A Rough Bundle of Brushwood

For me, gardening is a cathartic process. As Hugh Prather aptly said, “I touch the Earth and the Earth touches me.” The Earth and I are connected in a symbiotic relationship. This relationship is nurtured daily in my backyard. Our yard provides us with the opportunity to be an environmental steward 365 days a year. As an environmental steward, I am entrusted to care for the natural environment. I choose to care for the land by planting with a purpose, reestablishing biodiversity in our little piece of the ecosystem, and protecting the creek  from the effects of further streambank erosion. In this post I will focus on streambank stabilization practices that employ nonstructural, bioengineering measures such as fascines or wattles used together with vegetation as the methods of choice for protecting the streambank from further erosion.

Our property is located in the Bull Creek/Bull’s Brook Watershed. In general, watersheds drain the land  into a specific river, lake, or creek. Our land drains into Bull Creek, which then makes its way into the Upper Des Plaines Watershed. Today, much of suburban and urban land is covered with impervious surfaces such as roads and parking lots. These impervious surfaces reduce the soil surface area available to filter the rainwater runoff. The watershed surface’s inability to filter the water poses not only the threat of flooding but also endangering the health of the creek by allowing polluted runoff, including natural pollutants such as sediment, to enter the watershed.

Land Plat with Designated & Divided Restoration Areas in Green

To reduce the threat of  flooding and mitigate polluted runoff, we set out to incorporate streambank stabilization techniques into our riparian/prairie restoration plan. As previously referenced on our “About” page, Integrated Lakes Management (ILM) prepared a riparian evaluation that included site-specific recommendations. One of ILM’s recommendations for stabilization of the steep hill slope on the southeast corner of our property included using a technique referred to as bank shaping. Bank shaping is used to prevent creek undercutting via reduction of the bank’s slope. Earth movers, permits, and a lot of money are needed to facilitate the creation of this gradual drop in land contour along the riparian edge. That being said, this technique is clearly not accomplished by a DIY so we decided to address the erosion problem by building and installing fascines in conjunction with planting deep-rooted vegetation for soil stabilization.

Bioengineering techniques such as fascines or wattles are used to stabilize slopes. Slope stabilization is accomplished by shortening the slope face which results in runoff velocity reduction and an increase in trapped soil erosion particles. This method of streambank stabilization can use either live or dead plant cuttings or a combination of live and dead vegetation or inorganic materials, to produce living, functioning systems that provide habitats, sediment control, as well as prevent hill slope, streambank, and lakeshore erosion. Live fascines are constructed out of a bundle of dormant sandbar willow or dogwood cuttings that take root on the slope in the spring, whereas fascines made of dead, woody branches never take root but provide planting areas by reducing the hillside slope. Given the ample supply of dead brushwood at our disposable, we have chosen to construct and install brushwood fascines as part of our streambank restoration project. Fascine construction was accomplished in the following manner:

  1. Sixty to seventy, 5 to 8 foot long, dead branches with diameters of between 1/2″ and 2″ were gathered from our property to assemble about 10 fascines.
  2. The branches were trimmed to remove side and secondary branches.
  3. Five to eight branches of similar length, but varying diameters, were laid across the yard cart, alternating the orientation of tip to cut end.
  4. The alternating branches were tied together every 1 to 2 feet using non-biodegradable twine to form a bundle or log having a diameter of  around 8 to 10 inches.

Selected Brush Material for Fascine

Trimmed Brush

Tied Brush Bundle

Close Up of tied Brush Bundle

Close Up of Tied Brush Bundle

Installation of the fascines on the cleared, hillside slope was the next order of business. The fascines were  easily installed with the help of a hand shovel, shovel or a pick ax if the soil was particularly heavy, sledge hammer, and a bit of manual labor.

Fascine Drawing

First, a shallow trench was dug into the hillside that runs parallel to contour at the base of the slope. The removed soil was placed on the upslope of the trench. The trench was made deep enough to bury 1/4 to 1/2 of the fascine below the soil surface.  When more than a single fascine was needed to run the length of the trench, the fascines were overlapped to form a seemingly continuous brush bundle. Untreated, eighteen inch, wooden stakes purchased from Lowes were used to anchor the fascines at 2-3 foot intervals. The stakes were pounded into the down-slope soil and angled slightly away from the fascines. For extra stability, wooden stakes were pounded through the middle of the fascine at a 45° angle to the slope,  as well as driven into the up-slope soil and staggered over the down slope stakes pinning the bundle in place. Finally, the up-slope soil from the trench excavation was shoveled back over the top of the fascines and into the trench.

Installing a Fascine

Pinning the Brush Bundle

Additional trenches were dug up-slope of the initial line of fascines. The distance between trenches depends upon the slope of the site and the soil type. Our site has a very, steep slope (1.5 : 1) and loose, arid soil.  Experts recommend that the fascines be installed in rows 3-5 feet apart on loose soil that is very prone to erosion. However, on other sites where the slope is not as steep and soil not so loose, 5-7 feet between rows may be sufficient. Generally speaking, a good rule of thumb is to stand on the first row and dig the next trench as far up the slope as you can comfortably reach. As a result of this trench location method we ended up with fascine rows 2-3 feet apart.

Multiple Fascine Rows

Hopefully, the multiple rows of fascines installed along the steep, creek side slope we will do there job and trap sediment and reduce soil erosion. In addition to the fascines, we have planned on installing deep rooted native grasses and forbs to further stabilize the slope as well as act as a runoff filter. The combination of the fascines and the deep rooted native plantings should go a long way toward restoring, protecting, and sustaining the riparian environment.

  • Ohio Stream Management Guide.ODNR.com. Ohio Department of Natural Resources, n.d. Web.  1 Dec. 2011.
  • Using Stabilization Techniques: to control erosion and protect property.” tva.com. Tennessee Valley Authority, n.d. Web. 30 Nov. 2011.
  • Bull Creek Subdivision Erosion Control Plan.” Waukegan, IL: Integrated Lakes Management,  2009. Print.
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