Burandt Lake in Carver County southwest of the metro area is popular for recreation with lakeshore owners, but plagued by high levels of phosphorus that cause algae blooms. Algae can make the water unsightly and smelly for swimming, paddling and fishing. Some forms can even make animals and people sick.
This lake, which is 10 to 24 feet deep and covers 92 acres, is on the mend, thanks to a multi-pronged approach by state agencies and local partners.
This approach is like a health checkup for lakes and rivers, starting with water monitoring as a checkup, a study for prognosis with a prescription for restoration, and steps taken to achieve better lake health.
Water monitoring found that the phosphorus levels in Lake Burandt from 56 to 98 parts per billion, well above the water quality standard of 40 parts per billion. Because the phosphorus levels violated the standard, the MPCA placed Burandt Lake on the impaired waters list, kicking off a process to restore the lake.
The first step was a study called a Total Maximum Daily Load, which determines the maximum amount – or load – of a pollutant that a water body can accept and still meet water quality standards. The Carver County Water Management Organization led this study for Burandt Lake. In this case, the maximum amount is the water quality standard – 40 parts per billion – of phosphorus.
The study also figures the reductions needed to meet standards. For Burandt Lake, phosphorus loads into and within the lake need to decrease by 32 to 66%, depending on annual precipitation, to achieve the water quality goal.
The study identified the sources of phosphorus as stormwater running off developed and agricultural land, along with failing septic systems and degraded wetlands. The lake’s bottom sediment also contains phosphorus that causes algae when stirred up by wind and boat propellers.
With the prescription in hand, Carver County and partners are now taking steps to improve water quality with an innovative stormwater project.
The county is leading a partnership with the Carver County Soil and Water Conservation District, Water Management Organization, City of Waconia and the Waconia School District to implement a major water reuse project that should remove the lake from the list of impaired waters.
The reuse system is a three-phased project that will retain and reuse an estimated 1.25 million gallons off eight acres, to irrigate the Waconia High School football field and adjacent ball fields:
- The first phase included the installation of one storage tank, a cell that pretreats runoff, and a pipe network for future expansion.
- Phase two of the project received $200,000 from the Clean Water Fund established by the Legacy Amendment. This stage included the installation of three storage tanks.
- Two additional storage tanks will be installed in the final phase.
Reducing the stormwater also reduces the amount of nutrients flowing into the lake. Before this project began, almost 62 pounds of phosphorus flowed into Burandt Lake with stormwater runoff from this part of the lake. Once all three phases of this stormwater project are complete, that level should drop to about 14 pounds a year – a decrease of 77%.
The reuse project fits in directly with efforts to increase this kind of the use of runoff in the county. The project also fits with the Carver County Groundwater Plan which includes using stormwater runoff to help preserve the groundwater supply.
In addition, reducing phosphorus will help restore water quality in Burandt Lake and downstream because the lake discharges to Carver Creek, which flows into the Minnesota River.
This project is a great example of how state agencies like the MPCA and Board of Water and Soil Resources can work with local partners like Carver County to use the Clean Water Fund to restore waters based on scientific studies and long-term efforts.