Photo 9 MNRR Canoeists Floating Past the Bank Stabilization

Photo 8 June 2009

Environmental ConcernsThis specifi c stretch of the Missouri River, near Vermillion, South Dakota, is designated as the Missouri National Recreational River (MNRR) under the Wild and Scenic Rivers Act. The National Park Service (NPS) had concerns with conventional riprap bank stabilization applications and the ability to preserve the outstandingly remarkable values of the MNRR. To address these concerns, the bioengineered bank stabilization incorporated a soil-choked stone toe, 115 cottonwood and cedar tree locked logs, 48,000 unrooted willow plantings, and 59,300 rooted red osier dogwood plantings. This type of locked-log and willow planting bank armor stabilizes the eroding bank while maintaining the aesthetic characteristics of the MNRR and providing aquatic and terrestrial habitat diversity.

Permitting RequirementsThe U.S. Army Corps of Engineers (the Corps), South Dakota Regulatory, expedited the Section 404 permitting process so that the project construction could fi t within the threatened and endangered species time restrictions. This project required extensive coordination with the Bureau of Reclamation; Lewis & Clark; NPS; the Corps; U.S. Fish and Wildlife Service; South Dakota Game, Fish and Parks; South Dakota Department of Environment and Natural Resources; and South Dakota State University.

DesignTypical locked-log installations place the log at a 90-degree angle from the bank or point the log slightly upstream, with the rootwad in the waterway. This is reversed in our application for two reasons. First, the downstream orientation allows debris and ice to fl ow freely during these high-fl ow and ice-out conditions. Second, placing the rootwads in the revetment stabilizes both the log and the revetment.

ConstructionAfter grading the bank back to stabilize the slopes, the contractor placed 5,120 feet of stone toe revetment. Red cedar or cottonwood locked logs (113 total) harvested from the bank were locked into the stone toe, orientated slightly downstream to allow shedding of ice and debris. Throughout the riprap, 49,000 unrooted willow poles were integrated and 59,300 rooted stock

plants (cottonwood and red osier dogwood saplings) were planted along the upper bank. All of the exposed revetment was covered with soil and seeded with native grasses and forbs. The revetment also included animal travel corridors to allow wildlife to access both the river and the upland. Result

Constructed in the winter of 2007-2008 and followed by a wet spring 2008, the bank stabilization now blends seamlessly into its surroundings. This project serves as an example of using bioengineering techniques for bank stabilization on a major river system to protect infrastructure from lateral migration, yet preserving the natural state and restoring usable habitat for fi sh and migratory birds. In May 2009, this project was awarded the U.S. Department of Interior Partners in Conservation Award in recognition of outstanding conservation achievements attained through collaboration and partnership with others.

Project PurposeLewis & Clark Regional Water System (Lewis & Clark) is in the process of developing a high-quality three-state water supply system to serve the growing needs of southeastern South Dakota, southwestern Minnesota, and northwestern Iowa. In order to protect the well fi eld adjacent to the Missouri River (approximate river mile 777.8 to 776.7), Lewis & Clark would require a 5,120-foot-long bank stabilization.

BIOENGINEERED BANK STABILIZATION: Restoring eroded vertical bank to usable habitat in the Missouri National Recreational River

Omaha, Nebraska 68114Phone: 402-399-4983Fax: 402-399-1111Email: meagan.hall@hdrinc.com

Meagan HallHDR Engineering, Inc.

Approximate Well LocationSite B

Approximate Well LocationSite C

Approximate Well LocationSite D

VermillionSouth Dakota

HWY 50

319th Street

HWY 50

Missouri River

Dixon County,Nebraska

Clay County,South Dakota

South Dakota

Nebraska

Iowa

Minnesota

Project Location

Missouri River

Platte River

Source: USGS 7.5 Minute Quandrangle; Maskell Nebraska

LegendWell Site Locations

Site B

Site C

Site D

1 0 10.5Miles

Figure 2 Plan Cross-Section

Photo 2 Placing Stone Toe Revetment

Photo 3 Installing Locked Logs Photo 4 Soil Choking the Revetment

Photo 6 Rows of Willows Along BankPhoto 10 Canada Geese Using the Bank Stabilization

Photo 5 Planting Willows

Figure 1 Project Location

Photo 1 Existing Bankline

Photo 7 May 2008