Monitoring water quality is important for Minnesota lakes, helping us determine whether or not we are making progress in cleaning up our waterways. It reveals the health and composition of streams, rivers, and lakes at a snapshot in time, as well as over week, months, and years.

You might assume that in Minnesota, the land of 10,000 lakes, the state monitors the health of these waters every year. But because of the large size of area to assess, the state relies on residents who are willing to do it as a side passion.

Twice a month, residents or volunteers with the Minnesota Pollution Control Agency will use a Secchi disc, a white plate, to understand the state of a lake. The instrument will be slowly lowered into a lake until it’s not visible. After a set period of time, the disk will be brought up to the surface for a marking and a measurement.

Another tool used by monitors once a month is a vertical integrated sampler. This collects a column of water for chemical and biological analysis.

The samples are then poured into a bucket and sent over to a laboratory to check for two things: chlorophyll a, an element of a plant used in photosynthesis, and phosphorus, which can limit plant growth.

A few threats that volunteers monitor for are the presence of aquatic invasive species, like Eurasian watermilfoil or zebra mussels. Zebra mussels are filter feeders, and their activity can harm some fish species that prefer murkier waters. Eurasian watermilfoil is a weed that grows very thick and will choke out native species and degrade habitats for fish.

And even though a grass lawn close to the water’s edge may be aesthetically appealing, it’s best to leave bull rushes or natural vegetation to help wildlife and preserve water quality.

You can get more information on being a citizen lake monitor by visiting the Minnesota Pollution Control Agency website.

By — Hanky Hazelton