The key takeaways from the 2021 monitoring season are:
• Allen Lake had fairly high nutrient concentrations, high algal growth, and less-clear water. • Long-term trends suggest that water quality in Allen Lake has generally been improving over time, though there has been considerable variation from year to year. Overall, nitrogen, phosphorus, and chlorophyll concentrations have decreased, and Secchi depths have gotten deeper. • An algal bloom was sampled for toxin testing in May and September. Toxin testing found microcystin present in the September sample, at concentrations well below the Washington State Recreational Guidelines.
Please see below for a link to the full 2021 Allen 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).