2012-02-16_AgendaPacket - Laserfiche WebLink

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tLake Vegetation Management Plan ® Variance Requested by Cooperator ® Variance Approved (see Section VI) Section I: Lake Information Name: Owasso DOW Number: 62005600 County: Ramsey Fisheries Area: East Metro Surface Acres: 393, MN DNR Littoral Acres: 293 Classification: General Development Cooperator(s): Lake Owasso Association, Grass Lake WMO, City of Shoreview, City of Roseville and the MN DNR. Section II: Water Quality and Plant Community A. Water Quality ® Total Phosphorus: 79 ppb Date: 2000 -2009 June -Sept Summer Ave. ® Chlorophyll -a: 17.9 ppb Date: 2000 -2009 June -Sept Summer Ave. ® Secchi Disc: 1.46 meters Date: 2000 -2009 June -Sept Summer Ave. Narrative (describe water quality concerns, quantify TSI, NOTE if impaired or if TMDL exists): Carlson Trophic Status for Total Phosphorus: 67 (TSI(TP) = 14.42 ln(TP) +4.15 Carlson Trophic Status for Chlorophyll-a: 59 (TSI(CHL) = 9.81 ln(CHL) + 30.6 Carlson Trophic Status for Secchi Disk: 55 (TSI(SD) = 60 -14.41 ln(SD)) Overall Trophic Status: Eutrophicl7.9 Lake Owasso is a eutrophic lake. The amount of aquatic plant control in acres has remained the same or has decreased since 2000. The watershed district has been addressing water quality problems in the Lake and throughout watershed as has commissioned a major update of watershed management plans. B. Plant Community: Narrative (describe plant community, list plant surveys, include a table of percent frequency, and make sure to note rare species and species of concern): The Grass Lake WMO conducted a point- intercept plant survey in June 2010, which is the only recent plant survey that has been conducted on Lake Owasso. The Grass lake WMO also had conducted a plant survey in May, 2007. The June 2010 plant community was dominated by Eurasian Watermilfoil which is a non - native plant. Some other common and abundant aquatic plants found in the survey were Elodea, Slender Niad, and Chara. In 2007 Eurasian Watermilfoil (EWM) was found in 23% of the sites but in 2010 it was found at 54% of the sites sampled, a 135% increase in abundance. In 2007 curly -leaf pondweed (CLP) was found at 71% of the sample sites but it makes up only 17% of the points sampled in 2010, a decrease of 76% abundance. Currently, Lake Owasso is dominated by Eurasasin watermilfoil, the lake also has a fairly low occurrence of Curly leaf Pondweed at this time. We want to continue the trend of decrease in abundance of CLP, and we also want to see a decline in abundance of Lake Owasso LVMP