2000-06-08_AgendaPacket - Laserfiche WebLink

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MANAGEMENT STRATEGY Management Goal for Lake Owasso The management goal for Lake Owasso is to: Maintain the high quality of Lake Owasso and provide recreational use. Management Objectives Objective #1 Maintain high water clarity. Objective #2 Prevent Eurasian watermilfoil from becoming problematic. Objective #3 Provide safe and pleasant recreational uses. Objective #4 Find a solution for low lake levels. Objective #5 Coordinate lake management. Management Actions Objective #1 Maintain high water clarity. Lake Owasso's high water clarity is due largely to the `Shallow Lake Bonus,' meaning the lake's native aquatic plants provide an enviromnent that results in less algae and greater water clarity than expected based on the lake's phosphorus content. Thus, to maintain the lake's clarity requires two things: 1) continued protection of native aquatic plants and 2) the prevention of Eurasian watermilfoil or other exotic species. The lake's phosphorus content is not expected to increase because the watershed is no longer urbanizing and provisions for stormwater treatment are being implemented (GLWMO'). There are threats to protecting the lake's aquatic plants. The following is a list of concerns that generally threaten aquatic plants and apply to Lake Owasso: - Mechanical cutting and removal -some small-scale, private operations -Boat damage -water skiing and large (greater than 20 hp) motors - Herbicide use -nuisance aquatic plant control - Extreme water level fluctuations - Changes in fish populations and stocking All of these `threats' have been in play for a long time and lake clarity has not been affected, thus it is reasonable to proceed assuming the lake will stay clear. The prudent management strategy is to keep close tract of possible changes to the lake's condition so prompt mitigative actions can occur in the event of a change. Action tlu-esholds are proposed to be used to indicate a significant change in lake condition and result in a re- evaluation of the lake management activities: Threshold Description Water clarity The summertime average Secchi disk transparency is less than 8 - 9 feet. Phosphorus The sutmmertime average phosphorus concentration exceeds 37 - 40 ppb. Chlorophyll The summertime average chlorophyll concentration exceeds 11 - 13 ppb. Native Plants A significant departure from a contemporary baseline. Because we lack a contemporary aquatic plant assessment, we do not know what the aquatic plant