Water Quality Monitoring
Protect our Water Quality with “Shoreland Best Management Practices”
If you live at the lake, you can make a significant impact — pro or con — on Lake Vermilion’s water quality. How we each manage the shoreland on our property affects the lake we share. Check out these Shoreland Best Management Practices Fact Sheets assembled by University of Minnesota Extension. They cover a wide range of topics, including landscaping, erosion, septic systems, water wells, construction, lawn & gardens, woodlots, and wetlands.
Water Quality Definition
The federal Clean Water Act requires states to designate beneficial uses for all waters and develop water quality standards to protect each use. The MPCA has set standards in 4 areas:
- Beneficial uses – can people/animals/aquatic life use the water; is the water suitable for drinking, wildlife, navigation, aesthetic enjoyment, and industrial/agricultural uses
- Numeric standards – amount of specific chemicals and/or pollutants allowed in the water and still OK for use; what is acceptable (MN Rules chapter 7050 detail water quality standards); can encompass elemental (mercury for example) and biological (the presence of Eurasian milfoil, zebra mussels, starry stoneworts, curlyleaf pondweed, spiny water flea, and rusty crayfish as examples) analyses SEE ELEMENTAL ANALYSES sheet
- Narrative standards – statements of unacceptable conditions in and on the water such as floating debris, scums, oil films, or algae blooms
- Antidegradation protections – extra protection for high quality or unique waters (waters better than what is necessary to protect aquatic life and recreation) for future generations to enjoy; examples are waters of the BWCA, Voyageurs National Park, parts of Lake Superior, and the St. Croix River designated ORVW’s (outstanding resource value waters)
The EPA, through NARS (National Aquatic Resource Surveys), has also suggested water quality standards by measuring 4 areas:
- Secchi Depth – a measure of water clarity
- Total Phosphorous, TP – a nutrient which can trigger problematic algal blooms
- Total Nitrogen – same as TP
- Chlorophyll-a – a measure of algal population
Water Quality Monitoring – Recent Reports
Historical Lake Vermilion Water Quality Data
Secchi Disk Data
Historical Secchi transparency data, which date back to 1976, reveal a significant improvement in transparency based on 26 summers of data. During this 32-year period, the summer mean Secchi has improved from near 5 feet in the late 1970s to 8 feet in the late 1990’s. Mean values after 2000 have improved further to the 9-foot range.
The MPCA has compiled this historical Secchi data in an easy-to-read format here. While the data are from a single site in Big Bay near Pine Island, they are representative of the trends seen at other sites in Lake Vermilion.
Historical Secchi data from all monitoring sites in Lake Vermilion will be tabulated in the future.
Carlson Trophic State Index
The Minnesota PCA has developed an overall assessment of Lake Vermilion’s trophic status based on measurements of phosphorus and chlorophyll-a levels from the 2000 Lake Assessment Report and on recent Secchi disk data (see above). The Carlson Trophic State Indices computed from each of those methods are in close agreement, ranging from 46 to 51 (on a scale that ranges from 20 to 80). That places Lake Vermilion midway between the mesotrophic and eutrophic states.
For more detail on what the trophic state means and on the underlying data, click here.
For More Information on Water Quality Monitoring or to Volunteer
For more information on our overall water quality monitoring program or to volunteer to assist in this ongoing effort, please contact activity coordinator Craig Beveroth.