Red River Riparian Project
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Turtle River (Petsinger Site)
At this site, the lack of woody vegetation had left the stream bank vulnerable to severe erosion, a situation compounded by
groundwater seep above the base flow elevation of the river. Between 1978 and 1995, the river migrated approximately 3.5
feet per year to the east until it was only 80 feet from a nearby county road. When this bioengineering project was initiated
in 1995, the site had a vertical bank 14 feet high.
To stabilize the bank and stop further migration toward the road, several bioengineering techniques were implemented.
The first step was to create a stable slope for the vegetation. The 14-foot vertical bank was reshaped to a 3:1 slope, using
the waste material from the top as fill at the toe. Riprap was then installed along the toe to the bankfull elevation. Bioengineering
practices were installed as part of a workshop featuring the Natural Resources Conservation Service's (NRCS) bioengineering team from
Michigan. Willow fascines and a brush mattress were installed along the 300-foot length to armor the bank and to begin the revegetation
process.
Serendipitously, this project coincided with the largest flood of the century in the Red River Valley and thus sparked a new
appreciation for river systems. It has also been well positioned to offer solutions that recognize the characteristics of a
naturally stable river system.
Although some maintenance was required each spring in 1996 and 1997, the project bioengineering has survived spring
floods and a 17-inch rainstorm in July 2000. The lessons learned from experience at the Turtle River site include the following:
- Soil-plant material contact is best provided by using water to place the soil over brush mattresses and fascines. Sponsors used a power washer to wash in the soil placed by the backhoe.
- The loose fill used at the toe can be susceptible to erosion, especially in the first season. The site appears to have responded well to the repair work, but adding roughness to the toe would have helped.
- Deer and beaver find willow sprouts irresistible. At the Turtle River site, time will tell whether animals were detrimental to the survival of the willows.
The following series of photographs depict the restoration of the Petsinger Site. Click on an image for a larger version.
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This photo was taken before work began. The river had been eroding the bank away at a rate of nearly 3.5 feet per year. This rate of erosion continued through 1995 and had created a nearly vertical cutbank 14-feet high, approximately 80 feet from a local county highway. |
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Soil bioengineering crew. |
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Restoration began in October of 1995 with bioengineering techniques. The vertical slopes were reshaped to a 3 to 1 slope for stability. Boulder riprap, a brush mattress, and live willow stakes were used to strengthen the stream bank. |
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1996 - after one year. |
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1997 - after two years -- Brush mattress and rip rap installed at the site. |
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1998 - after three years. |
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Vegetation regrowth following the restoration activities. |
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1999 - after four years. |
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Aerial view of the site soon after the completion of the restoration effort. |
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Signage is put in place to highlight the site and the partners involved in the effort. |
| This site is located downstream of a USGS gage station. On June 13, 2000, USGS provisional data (subject to revision) measured a gage height of 20.69 feet, the highest historical height. The streambank in the area of restoration showed no severe erosion from the flooding, while areas upstream and downstream showed severe erosion. The three photos below were taken one month after the flooding. |
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Following a spring flood event that damaged the initial restoration effort, rock rip rap was installed to add increased stability and protection to the toe of the slope. These photographs were taken two years after the restoration activity began. |