Project Proponents: US Army Corps of Engineers St. Paul District and US Fish and Wildlife Service Big Stone National Wildlife Refuge
Project Authority: The Big Stone Lake – Whetstone River Project was authorized by the October 27, 1965, Flood Control Act (Public Law 89-298), to be constructed substantially as recommended by the Chief of Engineers in House Document No. 579, 87th Congress, 2nd Session. House Document No. 193, 88th Congress, 2nd Session, contains Supplementing information related to land acquisition for the National Wildlife Refuge System. Public Law 89-72 (1965) added recreation as a specific purpose to be considered at all Federal reservoir projects.
USACE operates and maintains the Highway 75 Dam near Odessa, Minnesota in coordination with the U.S. Fish and Wildlife Service pursuant to a water control manual, which includes a cooperative agreement, a general plan and 1975 Memorandum of Understanding (MOU) between the two agencies. The dam is integral to the Big Stone National Wildlife Refuge and was completed in 1974. Improvements to the upstream Minnesota River channel and modification to the existing Big Stone Lake outlet control structure were completed in 1987. The project was designed to be multipurpose in that it not only provides flood control, but also a means for the enhancement of migratory wildlife.
Sustainable Rivers Program: The proposed project is funded by the Sustainable Rivers Program (SRP). SRP is a nation-wide initiative and partnership between the Corps and The Nature Conservancy (a global environmental nonprofit) that looks at various watersheds and is focused on enhancing the environment through coordinated Corps-managed reservoir operations modifications. The SRP began in 2002, as an effort to find more sustainable ways to manage river infrastructure to maximize benefits for people and nature. The focus of the SRP is determining unique flow requirements for rivers and then creating operating plans for dams that achieve environmental flows to revive and sustain critical ecological functions and habitat for species.
Science from SRP sites is proving that re-operating dams and modernizing other river infrastructure as part of whole-river system increases the benefits they provide, particularly when done in coordination with stakeholders and Tribal partners.
Project Location: The proposed action would be located at the Highway 75 Dam near the Big Stone National Wildlife Refuge (Refuge) in Lac qui Parle County, Minnesota.
Summary of the Proposed Project: The St. Paul District is working in collaboration with the Refuge on the proposed Highway 75 Drawdown. The purpose of the proposed project is to improve wildlife conservation and habitat within the East Pool of the Refuge by conducting a gradual growing season drawdown every few years. The gradual drawdown, which will be performed by USACE, would expose mudflats across several hundred acres for the primary benefit of providing shorebird habitat and reducing invasive carp numbers. The proposed drawdown would begin following spring runoff (estimated around beginning of May) and run through approximately the end of October. A full drawdown is defined as reaching a target elevation of 942.3 feet. During an average year, the maximum discharge would be approximately 1,200 cfs and a full drawdown expected to be reached by mid-August. If a full drawdown is not reached by the end of September, then a full drawdown would not be possible that year. The primary flood control purpose of the Highway 75 Project would not be impaired to accommodate a drawdown of East Pool.
To maximize wildlife habitat values, the 7,000 linear foot trans-basin channel would be dredged by the Refuge to the as-built dimensions of elevation 942.0 feet, a 45-foot bottom width and 3:1 side slopes. Before dredging, the Refuge would test the material for contamination. If clean, approximately 60,000 cubic yards of dredged material would be placed over 32 acres of uplands and spread to an average depth of one foot. A seed mix would be spread over the material to stabilize the soils and to prevent it from washing back into the reservoir. The seed mix would include forbs and legumes favorable to pollinators, monarchs, and grassland birds. If the material is not determined to be suitable for upland disposal based on testing, the Refuge would need to dispose the material offsite in an approved location.
Summary of Environmental Impacts: Drawing down the Highway 75 project area during the growing season would 1) promote shorebird habitat, 2) promote the growth of desirable wetland vegetation, 3) reduce invasive carp abundance, and 4) improve habitat conditions for an abundance of wetland dependent species. However, any potential operating changes to the Highway 75 Dam would be consistent with current flood risk management and other authorized purposes of the Highway 75 Project. The proposed project would have minor, temporary adverse effects to air quality, water quality and noise, but have beneficial effects to aquatic habitat, wildlife, and recreation.
The proposed project will have no effect on federally listed species or their designated critical habitat. The proposed project may have effects on historic properties. No determination of effects on historic properties may be made until such survey for the identification and evaluation of site can be made. Therefore, the St. Paul District, the Refuge, and the Minnesota State Historic Preservation Office have agreed that under Section 106 of the National Historic Preservation Act of 1966, as amended, per its implementing regulation 36 CFR Part 800 a Programmatic Agreement is an appropriate course of action and its completion is in process.
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 project drawings, a Draft Finding of No Significant Impact, and letters of coordination from regulatory agencies.
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 draft Environmental Assessment can be directed to LeeAnn Glomski at LeeAnn.M.Glomski@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.