Bassett Creek Main Stem Lagoon Dredging Project - Phases I & II
Golden Valley and Minneapolis
Project Number: BC-7
Project Status | Proposed
PHASE II: A scope and budget for the feasibility study were approved by the BCWMC in August 2025 and the study got underway soon thereafter. A public open house on phase II will be held on Thursday, February 19th, 4:00 - 7:00 p.m. at The Trailhead (1221 Theodore Wirth Parkway). The draft feasibility study is slated to be presented to the BCWMC at their meeting on May 21, 2026.
COMPLETED PHASE I: After a detailed feasibility study, in May 2020 the BCWMC approved implementation of the project to dredge all 3 lagoons to a depth of 6 feet (Alternative 2-all). A public hearing was held September 17, 2020; there was no public input received at the hearing and the project was officially ordered by resolution. The project was implemented (designed and constructed) by the BCWMC in close coordination with the Minneapolis Park and Recreation Board. Project design at the 50% phase were approved in December 2021. 90% designs were approved in June 2022. Construction began in early January 2023 and dredging was completed in March. Site restoration was completed in spring/summer 2023. A final report and recommendations for future dredging projects was presented in December 2023.
Project Funding | Grant Funded
The cost of the original project (Phase I) in 2023 was approximately $1.5M with funding coming from a Clean Water Grant ($250,000) from the MN Board of Water and Soil Resources, a $74,000 Hennepin County Opportunity Grant, and funds were collected through ad valorem property taxes collected over 2021, 2022, and 2023 by Hennepin County on property within the Bassett Creek Watershed.
Estimated costs of the second phase of the project are approximately $2M.
Project Description
PHASE I (2023) This project removed sediment that collected in three of the seven “lagoons” created along the Main Stem of Bassett Creek in Wirth Park, between Golden Valley Road and Highway 55. These lagoons were originally created in the mid-1930s by Civilian Conservation Corps crews. A 2015 study found that the lagoons remained relatively unchanged until the early 1990s, when large amounts of sediment began to appear in the lagoons. The sedimentation appeared to slow or stop by the mid-1990s. The sedimentation in Lagoon “E” (immediately to the east of the chalet and parking area) was of concern to City of Minneapolis and Minneapolis Park and Recreation Board (MPRB) staff because the sedimentation may be contributing to flooding of the parking lot and a short section of Theodore Wirth Parkway. The sedimentation resulted in the creation of new “islands” in the creek/lagoons that reduced the flow capacity and floodplain storage of the creek.
The project was originally designed to remove almost 40,000 cubic yards of accumulated sediment by excavating the lagoons to a 6-foot depth. However, the project actually resulted in only the removal of 25,650 cubic yards and a depth of less than 4 feet. Still, the project resulted in a reduction of approximately 390 pounds of total phosphorus and 101,000 pounds of total suspended solids per year that previously flowed downstream in the creek and into the Mississippi River. The cost benefit analysis of the completed project calculates a cost of $210/pound of total phosphorus/year removed. Due to high levels of toxic substances in the sediment, all dredged material required landfill disposal.
Additional project benefits include improved flow capacity and floodplain storage, and improved habitat for fish and macroinvertebrates.
Options for PHASE II of the project are being studied in 2026 including dredging additional sediment from lagoons D, E, and F (building on the original project in 2023), dredging accumulated and contaminated sediment from lagoon G to recreate the original lagoon built in the 1930s, stabilizing the creek channel through lagoon G and restoring the adjacent wetlands that have formed over time, or a combination of these options.
Project Announcements
The BCWMC will hold a public open house regarding options for phase II of this project on Thursday, February 19th at 4:00 - 7:00 p.m. at The Trailhead (1221 Theodore Wirth Parkway, Minneapolis). Park users, neighborhood residents, and other members of the public are invited to learn about this proposed project and provide their input and insights. Open house flyer
More Information
PHASE I DOCUMENTS:
Final Report (Dec 2023)
Project FAQs and Project Flyer
90% Designs and Design Review Memo (June 2022)
EAW Findings of Fact and Record of Decision (Jan 2022)
50% Designs and Design Review Memo (Dec 2021)
Environmental Assessment Worksheet (Nov 2021)
Resolution Ordering the Project (Sept 2020)
Feasibility Study Report (no appendices) (May 2020)
Feasibility Study Report Appendices (May 2020)
Presentation of Feasibility Study (May 2020)
Feasibility Study Proposal (approved July 2019)
