DEEPHAVEN, MN - Wondering about the health of lakes across the west metro?
Well, you're in luck. The Minnehaha Creek Watershed District (MCWD) has released its 2012 Lake Grades, documenting the condition of 71 lakes and bays across the District.
The report is based on data collected by the MCWD, Three Rivers Park District, Minneapolis Park and Recreation Board and citizen monitors.
The MCWD bases its lake grades on water samples taken from May to September. It records data on three water quality parameters: Water clarity, algae growth and nutrients. To collect the data, staff:
- Measure water clarity by lowering a disk on a rope, a Secchi disk, into the water and recording the depth the disk disappears and reappears, and then averaging the two readings;
- Test for levels of Chlorophyll-a, an indicator of algae growth;
- Test for levels of Total Phosphorus, which can promote excessive plant growth
District staff average the scores of the three parameters to determine a lake grade on a curved scale from A to F.
- Lakes with an A grade are generally healthy and characterized by beautiful clear water. These lakes are well-suited for recreational activities of all kinds throughout the summer. A total of 21 lakes/bays (30 percent) received an A grade in 2012.
- Lakes with a B grade are also good for swimming and recreation, but late summer algae blooms may cut the season short. Twelve lakes/bays (17 percent) earned a B grade in 2012.
- The C grade signifies an average quality lake that may not be ideal for swimming, boating, and fishing due to summer algae growth. A total of 18 lakes/bays (25 percent) received a C grade in 2012.
- When a lake gets a D or F, it has limited water transparency, severe algae problems and very limited recreational use. A total of 15 lakes/bays (21 percent) received a D grade in 2012 and five lakes received an F (7 percent).
The 2013 lake sampling season got underway this week and MCWD staff will begin collecting even more data on the health of District lakes and streams. In addition to testing for water clarity, algae growth and nutrients,
MCWD also will begin documenting the presence of aquatic plants. It will start this work on Halsted Bay, Kelser's Pond, Church Lake and Turbid Lake in the Six Mile Creek subwatershed and will expand this monitoring effort to other subwatersheds of the District.
"The District recognizes that a variety of factors affect the health of our lakes and streams," said Kelly Dooley, MCWD Water Quality Specialist. "By expanding our monitoring effort, we hope to get an even clearer picture of the status of these ecosystems that will help guide future decisions on water quality improvement projects, education and outreach."
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