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Lake Owasso Task Force 12/18/96 minutes attending: Deane Anklan, Peggy Egli, John Gramer, Kate Linder, Sheila Prok. Jim Stark, Jim Vanous, Gary' Wood, Steve North absent: Betty Wolfangle guests: environmental panel, below chair. Gary Wood meeting begun, 7:05 PM 1. Approval of minutes from 12/4/96. The irunutes were unanimously approved. with the following correction: Kate Linder was present on 12/4 and was absent on 11/13/96. 2. Environmental panel -task force questions. Panelists: identifier Ed Musielewicz -Natural Resources Conservation Service EM Terry Noonan -Ramsey County Public Works Department TN Tom Peterson -Ramsey County Soil and Water Conservation District TP Joel Schilling -Short Elliot Henderson, Inc. JSch Dave Zappetillo - DNR Metro Fishery DZ 1 . What effects do weed and algae control hay e on aquatic ~ egetation, shorelines, and purple Icx~sestrife? What would be the effect nn aquatic vegetation, eater qualiq, and nay igable area if control was reduced to currently recommended ]erel s? DNR's division of Fish and Wildlife is responsible for plant management. Owasso treats 28%r of its 247-A littoral area (s l5' depth), while current law allows on1}' 15%, so that 37 A is "grandfathered" for weed control. The entire lake is 349 A., Aquatic plants and algae require nutrients (nitrogen, phosphorous, and potassium) for growth. Excess nutrients increase algal growth. The relative significance of external vs. internal nutrient sources is hard to predict, but addressing the source (nutnent inputs) vs. the s}'mptom (undesired weeds and algae) is the best approach to control. Most herbicide treatment is done from 5/1 to 7/15. Timing is critical because the herbicides kill by contact with vegetation. Early-season plants such as curly leaf pondweed normally die in June; as some species die others emerge throughout the growing season to utilize released nutrients. The August algal bloom is promoted by light, warmth, and release of nutrients from decomposing rooted plants. In-lake weed control would not affect purple loosestrife. Aquatic plants are good fish habitat but can be a hazard to boats or swimmers. -(DZ) Owasso's aquatic vegetation is less abundant than many other county lakes. About 24 to 31% of the lake (32-44% of the littoral area) has plants. Plant volume in the water column is 3-14%r in summer. Most species diversity and growth through July is in the SW end; elsewhere, flat, shallow-bottom areas contain mainly Chas, aloes-growing plant. Growth and species diversity (corntail, native milfoil, lily, Chas) increase in the mid- and E-basins by Aug.-Sept.. It is "unusual." that Owasso's shallow mid-basin. has so little plant cover. Owasso and Johanna have the highest weed control in the county. Some county lakes are 100% littoral, covered with vegetation, but are still considered recreational lakes (E. Silver, Island). Snail has open areas that have never been sprayed; White Bear and Snail are the clearest lakes. -(TN) 2 . Discuss the relationship bet~~een turbidit}~, aquatic vegetation, and fish populations. Fish populations were most recentl}' surveyed in 1996 but data are not yet available. Fish populations vary over time with environmental conditions. Most. Owasso fish are not impacted by turbidity (resuspended solids and/or algae). Walleye and crappie like turbid water, muskie are sight feeders but tolerate some turbidit}', and large-mouth