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Lake Monitoring Details <br />VLAWMO staff work with volunteers to collect samples from the lakes at two -week intervals from May through <br />September. At the time of collection, volunteers measure water transparency with a Secchi disk (SDT), evaluate the <br />physical and recreational conditions of the water, and if available, take a lake level reading. The samples are stored in <br />coolers and brought to the Ramsey County Department of Public Works Limnology Lab by VLAWMO staff for <br />chemical analysis. Parameters measured at the lab include Total Phosphorus (IP), and Chlorophyll -a (Chl A). The <br />data from these tests aid in the determination of the state of the water quality in a particular lake. Standards for water <br />quality are set by the US Environmental Protection Agency (EPA) and enforced through the MPCA. <br />A measure of the lake health and lake age is Carlson's Trophic State Index (TSI), which measures the productivity <br />level of a lake or degree of eutrophication. As a lake ages, it becomes more eutrophic, however human impact speeds <br />up the process. High TSI values correspond to poorer water quality. <br />TSI <br />TP (µg/L) <br />Chi A (µg/L) <br />SDT (m) <br />Oligotrophic <br />3-10 <br />2-5 <br />2.4-3.66 <br />Mesotrophic <br />18-27 <br />8-10 <br />2 <br />Eutrophic <br />30-50 <br />11-15 <br />1.2-1.5 <br />Hypereutrophic <br />>50 <br />>15 <br /><1.2 <br />Water quality grades are given to each lake based on standards established by the Metropolitan Council. The <br />standards give a range to each letter grade for the June — September averages of TP concentration, Chl A <br />concentration, and SDT. The overall lake water quality grade is the average of the grades for each parameter. Other <br />indicators of lake condition, such as aquatic plant growth or invasive species are not factored into the grades. As of <br />2007, the letter grades assigned to VLAWMO water bodies are as listed below: <br />Lake Name <br />Grade <br />TSI Status <br />Amelia <br />B- <br />Mesotrophic <br />Birch <br />B <br />Mesotrophic <br />Gem <br />C <br />Mesotrophic — Eutrophic <br />Gilfillan <br />C <br />Mesotrophic — Eutrophic <br />Goose <br />F <br />Hypereutrophic <br />Tamarack <br />D- <br />Hypereutrophic <br />Wilkinson <br />D+ <br />Eutrophic - Hypereutrophic <br />VLAWMO's summer intern began to enter data into the MPCA STORET program which makes the determination <br />of impairment. It is likely that some of VLAWMO's lakes will receive the impaired designation in the future and that <br />a TMDL study will need to occur. <br />Recommendations for Future Lake Monitoring <br />The addition of DO & water temperature data provided considerable information to VLAWMO's monitoring <br />program. Ramsey Washington Metro Watershed District and Ramsey County Limnology Lab collect turbidity, <br />conductivity, and pH data on the lakes the monitor. VLAWMO should consider collecting this data as well. To do <br />