The key takeaways from the 2020 monitoring season are:
• Shadow Lake continued to have fairly clear water, with moderate nutrient concentrations and algal growth. • Long-term trends suggest that water quality in Shadow Lake has been declining over time, with increasing phosphorus and chlorophyll concentrations, and shallower Secchi depths. In, contrast, the data also suggests that nitrogen concentrations have been decreasing over time. • An algal bloom was sampled for toxin testing in March. Toxin testing found very low concentrations of algal toxins, well below the Washington State Recreational Guidelines.
Please see below for a link to the full 2020 Shadow Lake Monitoring Report.
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The average of these three TSI indicators during the growing season can be used to place lakes in one of three broad categories: <40 = oligotrophic (low productivity), 40 to 50 = mesotrophic (moderate productivity) >50 = eutrophic (highly productive).