2018 Cooperative Lakes Monitoring Program  

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The 2018 Cooperative Lakes Monitoring Program (CLMP) report was issued and can be reviewed by clicking the button at the bottom of this post.  The results of the report cover the transparency, Phosphorus content, and Trophic Status.  This year’s program also included an Exotic Aquatic Plant Watch.

Transparency is measured using a Secchi disk, a very simple but effective method to determine water clarity. Phosphorus concentration is determined by taking water samples and sending them to a lab for processing. Phosphorus is one of the critical nutrients for algae growth and is important to monitor.  The Trophic Status Index (TSI) is a single figure used to assess the nutrient enrichment of a lake.  

The average Secchi depth is 16.7, which is the same as previous years.  The summer phosphorus sample is 6 parts per billion, which is lower than previous years. The TSI is also lower than previous years at 33, which is influenced by the Secchi depth and the phosphorus content.

The departure in phosphorus and TSI from previous years does not reveal any trends. It is normal for values to fluctuate from year to year. The purpose of the CLMP is to monitor lakes to prompt action when a clear trend in either direction appears. The next step would be to identify the mechanism causing the trend and come up with a solution.

The Exotic Aquatic Plant Watch surveyed multiple locations around the lake to identify and document the extent of invasive aquatic species. As of August 24th 2018, Gratiot Lake does not contain any of the invasive aquatic plant species on the watch list. For a complete list please review the report below.