Courtesy Photo | Andy Meier, U.S. Army Corps of Engineers, St. Paul District forester, and Dr. Chuck...... read more read more
“We’ve dug a lot of holes,” said Aaron McFarlane, Corps biologist, “and that’s just the beginning.”
Upper Mississippi River Restoration program
The Corps is moving dirt near Conway Lake, a habitat rehabilitation and enhancement project immediately upstream of Lansing, Iowa. Conway Lake is one of the ongoing restoration projects under the Upper Mississippi River Restoration program, or UMRR.
One component of the UMRR program is island building to restore lost habitat. Over the 35 years of the program, this has included a granular, or sand, base that is topped with fine-grained sediments consisting of slit and clay typically dredged from backwater areas. This approach mimics natural conditions in which fine sediments are deposited in floodplain soils during flood events and natural conditions throughout the Mississippi River Valley. While restoration sites are successfully planted with grass species, many sites have exhibited slow growth, low survival and at times substantial tree mortality. Now, spurred on by the efforts of McFarlane, researchers are beginning to change that narrative.
New research and development at Conway Lake, in partnership with the Engineer and Research Development Center, or ERDC, is looking at different baseline soil characterizations. Three different experiment test areas have been established as part of the Conway Lake project. Each test plot has a different depth of fine material placed over the sand base. The ultimate goal, said McFarlane, is to better understand the science of soil conditions and how it relates to vegetative response.
The work on research and development started this field season at Conway Lake, and that work will be leveraged for additional work at the McGregor Lake restoration project, near Prairie du Chien, Wisconsin. If funding can be secured, this will be a long-term research project that will inform future restoration projects. “This collective effort will help inform multi-million-dollar decisions for the UMRR program and help us maximize the ecosystem restoration benefit throughout the district,” said Zach Kimmel, program and project manager.
Ultimately, the UMRR program will have to weigh the benefits of the more expensive soil blending to see if the results are worthwhile. The blended soil can currently cost up to three times as much as a sand base, but the team also expects that costs may be reduced as new techniques are explored and implemented. “These studies will show what the soil looks like just after being constructed, and then we can watch them develop and observe how they change. I hope we can learn along the way, implement small improvements over time, and in the end greatly increase the likelihood of successfully establishing the prime habitat we are aiming for. This is a great example of adaptive management,” McFarlane said.
While there are no results from Conway Lake yet, ERDC has concluded its testing from soil samples that were taken from natural islands in Pool 5, near Fountain City, Wisconsin, and Pool 10, near Guttenberg, Iowa, and man-made islands in Pool 8, near La Crosse, Wisconsin, and Pool 9, near Eastman, Wisconsin.
This research showed that in natural sites, there are looser, less dense, less compacted soils with higher amounts of sand in them in general, and they are mixed with fine soil organic matter. This supports the idea that a blended soil base more closely mimics a natural island setting.
The ERDC Partnership
The St. Paul District is conducting experimental soil studies in partnership with ERDC, leveraging existing programs to inform the future of island building in the Upper Mississippi River.
McFarlane completed a six-month detail with ERDC University, which has been instrumental in kickstarting this research and creating those additional connections, Kimmel said.
“This soil data? It was a concern of a lot of other biologists, but it’s difficult to complete that research at a project level. With the ERDC University detail, I was able to start that initial research and establish a partnership with a lab that had an expertise in soil. Then, I was able to bring that back to the district and continue that partnership,” McFarlane said.
Programs being leveraged for the soil testing includes the Regional Sediment Management Program, Engineering with Nature, Dredging Operations Technical Support, and Dredging Operations and Environmental Research Program
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Story was originally published on Pages 11-12 of the Fall 2021 issue of Crosscurrents. It may also be found at https://www.mvp.usace.army.mil/Portals/57/docs/Public%20Affairs/Crosscurrents/2021/Fall%202021_final.pdf
| Date Taken: | 12.02.2021 |
| Date Posted: | 12.06.2021 15:40 |
| Story ID: | 410545 |
| Location: | ST. PAUL DISTRICT, MN, US |
| Web Views: | 78 |
| Downloads: | 0 |
This work, Partnerships on the Upper Mississippi River advance soil research, by Melanie Peterson, identified by DVIDS, must comply with the restrictions shown on https://www.dvidshub.net/about/copyright.
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