Lotus Lake Water Quality Improvement Project
About the Project
Background
The Minnesota Pollution Control Agency (MPCA) regulates water quality standards for lakes and streams in Minnesota. A waterbody that does not meet water quality standards is designated as "impaired" and must undergo study to determine the sources of pollution and how much a pollutant needs to be reduced in order to meet water quality standards. The plan to address the impairment is called the total maximum daily load (TMDL).
Lotus Lake is considered impaired for nutrients. The Lower Minnesota River Watershed TMDL: Part II (MPCA 2020) reported that a total phosphorus (TP) reduction of 47% (541 lbs/yr) was needed for Lotus Lake to meet water quality standards. The portion of the Lotus Lake watershed within the City of Chanhassen was identified as the only major contributor of external TP to Lotus Lake.
Purpose
The Lotus Lake Water Quality Improvement Project was a study that RPBCWD began in 2022 to identify projects within the Lotus Lake watershed that would achieve the TP reduction identified in the TMDL. The results of the study are presented in the 2024 feasibility report and include recommendations for five best management practices (BMPs) that would achieve the desired TP reduction.
The table below lists the five project areas (BMPs) identified in the 2024 feasibility report.
| Project area | Location | Proposed project | Working title of project |
| LL_1 | North Lotus Lake Park | Infiltration area | North Lotus Lake Park Water Quality Improvement Project |
| LL_3 | Meadow Green Park | Stormwater outlet modification | Pending |
| LL_7 | Meadow Green Park | Stormwater diversion and extended detention | Pending |
| LL_8 | Frontier Trail outlot | Infiltration improvements | Pending |
| Kerber Pond Ravine | Pond outflow area on east side of Kerber Pond | Ravine stabilization | Pending |
The figure below shows the five potential project areas (BMPs) identified in the 2024 feasibility report. Next steps are to develop preliminary designs for the projects and determine potential timelines for implementation.
Related Documents
Summary
A feasibility study was completed in 2024 that identified five projects that together would achieve a reduction in total phosphorus as prescribed by the Lotus Lake TMDL.
