Volunteer water monitors collect valuable data used by agencies and organizations across the state to protect and manage Minnesota’s waters. Data collected by volunteers can be viewed in a variety of ways.

A total of 1,367 volunteers collected data during the most recent monitoring season. The number of lake volunteers has decreased slightly over the past few years, with the number of stream monitoring volunteers remaining fairly stable since 2011.

Water clarity data

Water clarity is the primary measurement taken by our volunteers. Water clarity readings for lakes and streams are grouped into ranges, from poor to excellent.

These categories serve as benchmarks for comparing readings across lakes and streams in Minnesota. For the most recent monitoring season, more lakes were in the “Excellent” category than in previous years. The largest percentage of stream sites were in the “Very good” category, similar to previous years. A higher percentage of lakes fall into the “Excellent” category than streams, while more streams were in the “Fair” and “Poor” categories.

Water clarity trends

One of the uses for water clarity data is to determine water quality trends over time. To analyze water clarity data on a lake or stream, a minimum of eight years and 50 points of data collected between May and September is needed. Water clarity may vary from year to year in response to changes in rainfall amounts, watershed runoff and many other factors. Using datasets with more than eight years of data help to account for these factors.