Twin Cities Lake Water Quality
During the 2008 season, MCWD’s water quality staff will continue collecting water quality data for 34 lakes and 12 streams in the watershed. There will also be water depth measurements at 10 stream monitoring sites. Additionally, a comprehensive scan of Lake Minnetonka’s water depth will be recorded for the creation of a detailed map of the underwater contours of the lake. The most recent publicly available map of this sort was created in 1957.
To calculate lake grades, MCWD’s water quality monitoring staff measure water clarity, nutrient levels, and algae growth throughout the open water season. Those results are averaged into a numerical score which is translated into a lake grade between A and F.
Lakes are graded on a curve; the C grade means that a lake is typical for lakes in the seven-county Twin Cities metropolitan area. C lakes may not be ideal for swimming, boating, and fishing due to summer algae growth. Lakes in the A grade range have clear water and are suitable for recreational activities. B-quality lakes are considered good for recreational use but may suffer from algae growth later in the season. Lakes stamped with an F have...