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<br /> <br />Gem Lake News Page 2 of 6 <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> A report on storm water runoff in the city was <br />recently completed by the Ramsey <br />Conservation District for the Vadnais Lake <br />Area Watershed Management Organization <br />(VLAWMO). The report was recently presented <br />to the City Council for review by Stephanie <br />McNamara of VLAWMO. In most sections of <br />the City of Gem Lake, storm water is properly <br />running off, bringing a minimum of pollutants <br />into the water body of Gem Lake. (Gem Lake is <br />a 22 acre lake, with a much larger wetland <br />area around it, and an average depth of nine <br />feet.) However, the report did highlight that one <br />area of the city's business section has certain <br />topographical features that do not allow for <br />optimal runoff and/or on-site absorption of <br />storm water. <br /> <br />This part of town is contributing more than an <br />average amount of pollution to the lake. The <br />report suggests various options to retrofit the <br />area so that storm water gets absorbed where <br />it falls and less pollution reaches the lake. <br /> <br />The report was discussed in more detail at the <br />City Council Meeting on June 19. <br />The Ramsey County Conservation District <br />divided Gem Lake into three main sections. <br />Sections One and Two comprise most of the <br />residential sections of the city. These sections <br />were determined to consist primarily of low <br />density housing and large <br /> <br /> <br />Storm Water Run Off Increases Pollution in Gem Lake <br /> <br /> <br />open spaces with plenty of green space. <br />Due to these factors, it was determined that <br />they are contributing very little in terms of <br />total phosphorous (TP) and total suspended <br />solids (TSS) that reach the water body of <br />Gem Lake. Due the green space, most of <br />the potential pollution coming from storm <br />water runoff is being properly absorbed in <br />place. <br /> <br />With the Gem Lake business district, <br />particularly in the area surrounding the <br />County Road E and Highway 61 <br />intersection, the amount of impervious <br />ground cover (blacktop, etc.) means that <br />storm water runoff doesn't have a chance to <br />sink into the soil. Instead, it ends up in Gem <br />Lake or its surrounding wet lands. <br /> <br />The Ramsey County Conservation District <br />suggested various ways to retrofit sections <br />of the business district in order to cut down <br />on pollution. Suggested methods include <br />the incorporation of grass swales and bio- <br />filtration into areas there are large swatches <br />of parking lots and blacktop. Installing a <br />grass swale would require replacing turf <br />grass with native plants that improve <br />filtration. Bio-filtration improves the ability of <br />the soil to absorb and filter potential <br />pollution. The report will be discussed in <br />more detail at city council meetings this <br />summer and fall. <br /> <br />McNamara's presentation to the council <br />emphasized that Gem Lake is now <br />considered in impaired lake by the State of <br />Minnesota due to increasing levels of <br />phosphorus and other pollutants that are <br />making it to the lake. The study shows that <br />approximately 86% of the pollution is <br />estimated to come from storm water run-off, <br />also called watershed load. The amount of <br />phosphorus in the lake has gone up over <br />the last 10 years and now needs to be <br />addressed. State Law requires that cities <br />with impaired lakes develop plans to reduce <br />pollution. In our case the phosphorus levels <br />would need to be reduced by 24% in order <br />to bring Gem Lake and its large surrounding <br />watershed into average levels of water <br />quality and off the impaired list. <br /> <br />(continued on page 4) <br /> <br /> <br />