Laske Owasso Task Force - Laserfiche WebLink

Home

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 P11�1 1. Approval of minutes from l2/4/96. The minutes 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: identifrer Ed Musielewicz - Natural Resources Conservation Service DVl Terry Noonan - Ramsey County Public Works Department TN Tom Peterson - Rarnsey 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 ha��e on aquatic ��egetation, shorelines, and purple lcx�sestnfe? What would be the effect on aquatic vegetation, water qua4ity, and na��igable area if contr�l w•as reduced to currentl} r�ecommendedlevels? - . DNR's division of Fsh and Wildlife is responsible for plant management. Owasso treats 28°Io of its 247-A littoral area (s l5' depth), while cunent law allows only 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 signi�icance of external vs. internal nutrient sources is hazd to predict, but addressing the source (nutrient inputs) vs. the symptom (undesited 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 aood 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�4% of the tittoral area) has plants. Plant volume in the water column is 3-14% in summer. Most species diversity and growth thmugh July is in the SW end; elsewhere, flat, shallow-bottom areas contain mainly Cht�a, a low-growing plant. Growth and species diversity (corntail; native milfoil, lily, Chc�a) 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 between turbidity, aquatic vegetation, and fish populations. Fish populations were most recently 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 turbidity, and large-mouth