Minnetonka
Project Overview:
Lake Rose is a small, shallow lake primarily amongst residential properties in Minnetonka. In 2022, the district conducted a lake water quality study to identify potential projects to improve the health of Lake Rose. The study found that while water quality has generally been improving, additional efforts are needed to further reduce nutrient inputs. Phosphorus in Lake Rose comes from multiple sources, including stormwater runoff from the watershed, inflow from the upstream Wing Lake, and internal loading from nutrient-rich sediments. A 2023 feasibility study evaluated potential management strategies and identified two key approaches: alum treatment to reduce internal phosphorus loading from sediments, and enhanced street sweeping within the Lake Rose subwatershed to reduce external nutrient inputs.
The Nine Mile Creek Watershed District Board of Managers ordered the Rose Lake Improvement Project in December 2023. The projects on this lake seek to improve the water quality and specifically reduce the amount of phosphorus, an algae producing nutrient, in this lake.
Project Details:
The district completed a combination of activities in 2024 to help reduce the amount of nutrients contributing to poor water quality in Lake Rose and improve overall lake health:
Enhanced street sweeping
The City of Minnetonka is currently doing an additional fall street sweeping in the Holiday, Wing, and Rose sub-watersheds in addition to its routine spring street sweeping. In the future, the watershed district will assess if additional sweeps are needed to help reach water quality goals for the lakes, and, if needed, how to implement additional sweeps.
Project Updates:
The district has made several attempts to move forward with the planned alum treatment. A bid was received in 2024; however, the project could not proceed due to low water levels. In 2025, bids were not solicited after the contractor indicated they would be unavailable. In early 2026, a new request for bids was issued, but no responses were received.
As a result, the alum treatment will not move forward in 2026
Community Engagement:
A public open house was held on December 5th, 2023, at the Minnetonka Community Center. This was a drop-in event where residents could view informational posters and ask staff questions about the proposed water quality projects. Other community engagement events were held during the development of the water quality study
Project Timeline:
- August 2022: Water quality study complete
- December 2023: Feasibility study complete
- December 2023: Project ordered by watershed district
- 2024 and beyond: Monitoring and evaluation
- 2024: Water Quality Monitoring Report 2024: Lake Rose
- TBD in 2027: Aluminum treatment
Resources
Holiday, Wing, and Rose Lake Studies
Questions?
Contact Jordan Wein, Water Resources Project Manager, at 952-800-8307 jwein@ninemilecreek.org