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651 Hale Avenue North Oakdale, Minnesota 55128 Table 4. Summary of the Recommendations and Main Findings of the Lake Owasso Use Attainability Analysis telephone: 651.]]0.8448 facsimile: 651.]]0.2552 www. e o ri a c. coin Recommendation Main Findings ofthe UAAthat Supportthe Recommendation Howwas Recommendation Prioritized inthe UAA Where is Recommendation Contained in 2011 Watershed Management Plan External Load Source: Internal Loading from Watershed Waterbodies Additional monitoring in the deepest portions of the - Grab samples collected between storm events at County Road [(Cenral 1. Water and phosphorus budgets developed for Lake Owasso for various Implementation Activity 1.La— Develop Subwatershed Studies Implementation Activity 1. Lb— Conduct plan amendment to incorporate Central Park— east wetland, the Central Park — west Park — west wetland) during the summer of 2008 indicated that the climatic conditions indicates that internal loading from contributing TMDL wetland, and the Charlie Pond system. concentration of the wetland was significantly higher between storm events waterbodies ranges from S to 9 percent that the concentrations observed during actual storm events, indicating the Implementation Activity 1.20.c — Consider barley straw treatment for lake Emily (addresses phosphorous loads for all waterbodies in potential "internal" loading of TP within the wetland (due to carp activity, phosphorus release from sediments, and other biological activity in the contributing watershed) wetland). Implementation Activity 1.32.a— Short - circuiting on Charlie Pond Implementation Activity 1.19.f— Barley straw treatment on Bennett Lake - "Because the specific sources of these "internal" loads (internal loading from waterbodies in the contributing drainage area) are not fully understood at (addresses phosphorous loads for all waterbodies in contributing this time, additional monitoring and studies are recommended for several of watershed) these water bodies to more completely understand the systems. The focus of these studies will be additional water quality monitoring, quantifying the potential impacts of the sediments on the phosphorus load, and the observations of carp activity in some of these waterbodies." (page xlvi). Fisheries( carp) impacts study on water goal ity. - 2001 M DN R fi sh survey i ndicates that small numbers of carp are present in I mplementati on Activity 1.4.c— Develop regional approaches to carp Lake Owasso. mgmt Implementation Activity 1.4.d — Keep up to date on other efforts to manage carp Implementation Activity 1. 19.1h — Explore fish management goals for Bennett Lake Implementation Activity 1.19A — Fish kill to restore balance in Bennett Lake Implementation Activity 1.31.a —Carp management in Central Park Wetlands Sediment Core Collection and Analysis Internal Loading Water Quality Monitoring in Lake Owasso — Shallow Area - Internal phosphorus loadingfrom thebottom sediments(of Lake Owasso) Implementation Activity 1.2.b— Develop optionsto Protectshallow portions of Lake Owasso identified during analysis of dissolved oxygen levels during the summer months Implementation Activity 1.9.a — Build fund to address internal loading as - "Additionally, anecdotal evidence indicates that motorboat activity results in needed the resuspension of bottom sediments in shallow areas of the lake." (page Implementation Activity 1.9.c —Carp management xxii) It is unclear what role mixing and resuspension in the shallow areas of Implementation Activity 1.9.e —Wind mixing the lake have on the overall water quality in Lake Owasso (page xliv). Implementation Activity 1.9.f —Test impacts of establishing no wake - The predicted total phosphorus concentrations based upon the lake's zone specific conductivity and alkalinity are lower than the total phosphorus Implementation Activity 1.9.g — Evaluate alum treatment concentrations for monitoring sites 5401 and 5403 indicating that some improvement in lake water quality may be attainable. CLP Management Plan - In 2007, approximately 52% of the lake was covered by CLP and review of 1. Lake user survey indicated that residents have concerns about Implementation Activity 1.9.a —Build fund over 5 -year period historic macrophytes surveys and other reports indicates that CLP has been macrophyte interference with recreational uses of the lake as well as Implementation Activity 1.9.6— Use LAC to assist LOA with vegetation present in the lake since 1981. decreasing lake clarity. issues - The relationship in Lake Owasso suggests that the algae concentrations in 2. Water and phosphorus budgets developed for Lake Owasso for various Implementation Activity 1.9.d— Evaluate options for CLP Lake Owasso are not directly controlled by total phosphorus and are climatic conditions indicates that internal phosphorus loads range from Implementation Activity 1.10.a— Address spread of aquatic invasive impacted by zooplankton grazing to some extent. 50 to 57 percent species 3. Implementation of a CLP management plan — "In -lake modeling indicates that the control of CLP will have the most significant impact on the total phosphorus concentrations and water clarity in Lake Owasso during the summer months, for all climatic conditions." External Load Source: Watershed Runoff Structural Recommendations :'Though no one specific - BMPs were evaluated to comparetheir relative effect on the total 1. Water and phosphorus budgets developed for Lake Owasso for various I Implementation Activity 1.1.a— Subwatershed Studies An Equal Opportunity Affirmative Action Employer Emmons & Olivier Resources, Inc. water I ecology I community