Project Proponent. St. Paul District, Corps of Engineers, 332 Minnesota Street, Suite
E1500, St. Paul, Minnesota 55101.
Project Authority. Section 128 of the Water Resources Development Act (WRDA)
2020, directs the Secretary of the Army (Secretary) to implement a demonstration
program to determine the causes of, and implement measures to effectively detect,
prevent, treat, and eliminate harmful algal blooms (HABs) associated with water
resources development projects. Section 128 requires the Secretary to consult with
federal and state agencies, and leverage data and activities of the Secretary carried out
through the U.S. Army Corps of Engineers (USACE) Engineer Research and
Development Center (ERDC) pursuant to Section 1109 of the WRDA of 2018 (33
U.S.C. § 610).
Project Location. The proposed project would be conducted in three stormwater ponds
in the Minneapolis, MN metropolitan area (Figure 1).
Summary of the Proposed Project. Researchers with University of Minnesota Twin
Cities and University of Minnesota Duluth are studying the efficacy of modified clay
removal methods for HABs in ponds and lakes. The proposed alternative would use
physical clay treatment methods to remove HABs on stormwater pond sites within
Minneapolis, MN. The modified clay used specifically for this study includes a synthetic
clay known as laponite, and a modified naturally occurring clay known as kaolinite.
Field trials would be conducted in three stormwater ponds in the Minneapolis, MN
metropolitan area (Figure 2). These ponds were chosen because of their size, ease of
access, and history of algae blooms. To conduct the study, two 330-gallon (1250 L)
intermediate bulk container (IBC) totes would be placed at opposite pond shores at
ponds B and C. IBC totes would be fitted internally with a custom-made mechanical
stirrers and equipment necessary to spray a clay-water mixture onto the surface of each
pond. Researchers would conduct laboratory-scale trials using pond water prior to
conducting field trials to determine the laponite and kaolinite loading required to achieve
80% algae removal.
After the application of modified clay technologies to the ponds, samples would be
retaken 2 and 72 hours after the trial and then weekly for the next 8 weeks. Samples
would be analyzed for total algae, cyanobacteria biomass, and other variables to analyze
the efficiency of laponite and kaolinite at removing HABs within the stormwater ponds.
It is anticipated that this work would either take place in the summer of 2026 or 2027.
Summary of Environmental Impacts. The proposed action would have temporary
minor adverse effects to recreation and temporary minor benefits to water quality,
biological productivity, and aesthetic value within the project area. Affected resources
would be expected to recover from any adverse effects shortly after conclusion of the
project. The project would have no effect on federally-listed species. The Corps
determined the project will have no effect to historic properties, which is currently
being coordinated with the Minnesota SHPO. Overall, this project would provide
valuable experience and results for other HAB studies covered under Section 128 of
WRDA 2020.
Report. A Draft Environmental Assessment that describes the project and the
environmental impacts in detail is available to the public and can be viewed at
https://www.mvp.usace.army.mil/Home/Public-Notices/. The report includes a Draft
Finding of No Significant Impact.
Review and Comment. If you have any comments on the Environmental Assessment
they should be provided before the expiration date of this notice. Persons submitting
comments are advised that all comments received will be available for public review, to
include the possibility of posting on a public website.
Questions on the project or comments on the Environmental Assessment can be
directed to CEMVP_Planning@usace.army.mil. Please address all formal written
correspondence on this project to District Engineer, St. Paul District, Corps of
Engineers, ATTN: Regional Planning and Environment Division North, 332 Minnesota
Street, Suite E1500, St. Paul, Minnesota 55101.
