For many years now, members of your lake association have been measuring water clarity by recording secchi disk transparency. This is done by lowering a white disk into the water and measuring and recording the depth at which the disk is no longer visible. This is done several times throughout the summer. Secchi data from 1981 to the present can be found on the DNR Lake Finder website at www.dnr.state.mn.us/lakefind/index.html. Enter our lake and click on go, under water clarity.
In 1991 our lake association teamed with the MPCA to enter into their lake assessment program (LAP). The LAP program consisted of a detailed study of our water by taking monthly water samples throughout the summer to gather water chemistry data. This data is then analyzed and converted into a Carlson Trophic Status Index (TSI) score. The Carlson Trophic Status Index (TSI) is a tool used to summarize several measurements of water quality into one index value, which can be used to compare a lake to other lakes, or to compare historic/future data as a measure of degradation or improvement.
Trophic state is defined as the total weight of living biological material (biomass) in a waterbody at a specific location and time. Time and location-specific measurements can be aggregated to produce waterbody-level estimations of trophic state. Trophic state is understood to be the biological response to forcing factors such as nutrient additions, but the effect of nutrients can be modified by factors such as season, grazing, mixing depth, etc.
In many ways, the index can be viewed as a measure of the potential for algal productivity. Since most people value lakes with low algae productivity, the lower the TSI value the healthier the lake.
A considerable amount of data has been collected through water sampling done throughout the years. In 2003, 2005 and 2006 the Lake Association began taking part in a water sampling program provided by the Crow Wing County Outdoor Corps. The program is managed by the University of Minnesota Extension Service and is designed to train local high school students in limnology and sampling protocol. Additional sampling was done by your lake association in 2008 , 2009 and 2010. The results for 2009 & 2010 can be found on the RMB Environmental Laboratories website at www.rmbel.info/Reports/ReportsQuery.aspx.
The downside to water sampling is that the results are hard for most if us to understand, it takes a considerable amount of a volunteers time, it can be costly and over the years the data has become scattered and as a result has not been compared on a long term basis.
Late in 2009 all of our scattered historic water sampling data was given to the MPCA to be included in their new water quality data management system. The implementation of the new system should take place in the spring of 2011.