Meadow Lake Watershed Potential Project

In the Spring of 2019, the Shingle Creek Watershed Management Commission (SCWMC) informed members of the Meadow Lake Watershed Association (MLWA) that there was potential to conduct a in-lake treatment project in Meadow Lake to address ongoing internal phosphorus loading issues. 

The SCWMC, MLWA and city staff met in May of 2019 to discuss what the potential project timeline would be and what this project may look like. Data had been collected previously on Meadow Lake that shows the lake has a very high internal phosphorus loading, making it a viable for the Shingle Creek Commission's in-lake treatment project program. The Shingle Creek Watershed Management Commission would fully fund this project, although the city will be looking at external phosphorus loading and may contribute funding to address any external issues. 

The City will be holding an open house on July 30th to discuss the potential project on Meadow Lake. Representatives from the city, the city engineer, and the watershed engineer presented information regarding the potential project and answered many questions residents may have. The presentation and FAQ's are located in the "Open House Materials" and "Open House Discussion" sections below.

The watershed engineers are currently working on a grant application for this project. The results of the grant application will be discovered in January of 2020. If awarded and authorized by the property owner's on Meadow Lake, the monitoring of Meadow Lake would begin in Spring of 2020 with the winter drawdown beginning in September of 2020. If the grant is not awarded, the project would begin in Spring of 2021.

Project Information

In general, the potential project would involve a winter draw down of Meadow Lake, beginning in September of either 2020 or 2021. Prior to the draw down, water quality will be measured for the entire Spring/Summer/Fall to establish accurate base line data. A draw down allows for mucky lake bottom sediment to be exposed to winter weather, which will help compact the sediment. In addition, a full draw down will kill a majority of the curly-leaf pond weed in the Lake. Following the draw down, at least 2 years of water quality monitoring will take place to determine how the lake reacted to the draw down. It is possible a shorter, summer draw down would be necessary to see the desired effects on the lake, plant, and fish ecology.

Once the desired effects are seen, a dosage of chemical treatment will be determined, such as an alum treatment. At this time, this could take place in either Year 4 of the project, or later on. Watershed engineers will carefully monitor the lake to determine the correct timing, chemical, and dosage prior to any application. The intention of the chemical dosage is to "lock-in" the lake bottom sediments that have been compacted by the draw down, to prevent sediment release over time. 

Overall, if this project moves forward, it is the Shingle Creek Watershed Management Commission and the City's goal to thoroughly study Meadow Lake over the next 4 to 8 years to ensure that the lake's functions are fully understood prior to any draw down or any chemical treatment. 

Supplemental Watershed Information


The most recent lake data can be found in the SCWMC 5-year TMDL report. 

- Full 5-year Report
- Summary Report

This report is assembled by the Shingle Creek Watershed engineers every 5 years to review any progress made towards addressing the TMDL (total maximum daily load) assigned to a water body by the state. Meadow Lake is currently listed by the MPCA as impacted for Nutrients. This means that the phosphorus concentrations in the lake exceed the allowable daily levels. Information regarding the state's listing of Meadow Lake can be found below.

- MPCA Meadow Lake Website

The Meadow Lake Watershed Association has many useful sources of information assembled on their website, which can be reached by visiting the link below.

- Meadow Lake Matters

The city of Plymouth has recently treated Bass and Pomerleau lakes with Alum. CCX media has a story with video of the alum treatment available below. 

- Plymouth Alum Treatment

Open House Materials

A copy of the presentation given can be found below. The presentation was given by Diane Spector who is a water quality scientist with Wenck Engineering, the Shingle Creek Watershed Commission engineer.

- Open House Presentation


The SCWMC in partnership with other local watershed districts recently published a helpful brochure that highlights actions individual property owners can do to address local watershed issues. A digital copy can be found below, or hard copies are available at Public Works.

- 10 things you can do to protect Minnesota's lakes, rivers, and streams

Open House Discussion
Would a full dredge of Meadow Lake be more effective long-term than treating the existing lake sediment?

A full dredge of the sediment of Meadow Lake is feasibly impossible. Not only would this work cost upwards of 1.5 million dollars, the DNR would not permit this work to occur. Partial dredging of the 'deltas' of sediment near the storm water inlets to the Lake has been permitted in the past and if necessary will be part of this project. 

Many residents have planted native shoreline plantings on Meadow Lake. How would a full winter draw down or a potential summer draw down affect these assets?

During the winter draw down it is likely that residents will see native shoreline plantings die off. These plants typically have deep roots and a strong, healthy seed bank. One of the main purposes of the draw down is to kill the invasive curly-leaf pond weed in Meadow Lake. This plant prevents the native vegetation in the lake from flourishing. Watershed engineers expect that the Spring after the draw down that residents would see native shoreline plantings return not only on the shorelines of the lake but in the lake bed as well.  

​How does the golf course pond to the southeast of Meadow Lake interact with the lake itself?What work will be done to this drainage basin to prevent any negative impact to Meadow Lake?

​City staff are in the preliminary stages of investigating the golf course pond. The pipe between Meadow Lake and this pond will likely need to be replaced during the winter draw down. Staff expects to need to draw down this pond as well to prevent fish refuge in the deep well of the pond over the winter. Sediments may need to be excavated or chemically treated to prevent phosphorus release into Meadow Lake. A fish barrier may need to be installed if fish can not be controlled by other means. 

There is a healthy turtle population in Meadow Lake. How will a winter draw down affect the turtles and what measures will be taken to protect them?

The DNR non-game wildlife specialist will review this project prior to any action. The permit for the draw down requires that the lake be fully dry by mid-September to promote turtle migration prior to any deep freeze. On other draw downs, fencing has been installed to direct turtles to specific areas of refuge, or turtles have been physically relocated. 

75% of lake-shore properties are required to 'sign off' on the draw down for the DNR to permit the project. What would happen if residents did not want this project and nothing was done to address the internal phosphorus of Meadow Lake?

Currently the curly-leaf pond weed is identified in about 55% of the lake. Without treatment, this will continue to rise until the weed is located in 100% of the lake. When the curly-leaf pond weed dies in early summer, it leaves the lake without any vegetation. The fish in the lake begin to feed on the sediments and on the zooplankton, which greatly decreases the clarity of the water, and increases the chlorophyll (algae) content in the lake. This increases the likelihood of blue green algae developing in Meadow Lake, which is toxic. Overall, the lake would continue to deteriorate and would get increasingly difficult and more expensive to treat.

The city has performed an alum treatment in the past. There were a few years of better water clarity after the treatment, but the lake returned to its turbid state. What would be different with this treatment?

When Meadow Lake was treated previously, engineers did not know nearly as much about the correct dosing levels. In order to prevent any adverse or unknown effects, the dosing levels of alum were much, much less than is currently recommended. The watershed will be collecting at least 2 years of data after the winter draw down to ensure that the dosing is correctly calculated. It is possible that in order to determine the correct dosing that more data is necessary, and the alum treatment will be delayed until the watershed engineers can determine exactly what treatment is necessary to correctly treat the lake sediment. 
DRAFT Grant Application and Feasibility Study

Copies of the Clean Water Fund grant application and of the project's Feasibility Study are available below. The grant application is due by September 7th, and results will be known in early January.