CITY OF EAU CLAIRE: Half Moon Endothol 2


The City of Eau Claire proposes to conduct a second, whole-lake application of the herbacide Endothall, in the form of Aquathol K, to Half Moon Lake in Eau Claire County to control Curly Leaf Pondweed. Major project elements to include: a) chemical treatment, b) pre- and post-treatment plant surveys, c) pre- and post-treatment water quality monitoring, d) re-evaluation of phosphorus inputs from storm sewers, and e) final report.

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Aquatic Invasives Grant
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Reports and Documents
The aquatic plant community of a lake is full of complex interactions that contribute to the overall health of an aquatic ecosystem. Every level of the aquatic food chain from bacteria and invertebrates to fish and waterfowl are dependent upon aquatic plants to some degree for their survival (Engel, 1985; Wetzel, 2001). Photosynthesis and respiration are important in maintaining clear waters (Engel, 1990). Aquatic plants stabilize sediments and absorb wave action which in turn prevents turbidity caused by suspended sediments. Light penetration, excess nutrients from run-off, wave action and lake morphometry all affect the plant community of the littoral zone (Barko 1988; Duarte and Kalff, 1986). The importance of aquatic plants in an aquatic ecosystem creates the need to study the diversity, density and distribution of the aquatic plant community as well as an examination of the factors impacting the plant community.
Management to reduce internal phosphorus (P) loading and algal growth to improve underwater light condition for native aquatic plants has been threefold for Half Moon Lake, Eau Claire, Wisconsin (James et al. 2002). Motor boat activity has been restricted on the lake to reduce P resuspension. Canopy-shading of native macrophytes and P recycling caused by curly-leaf pondweed decomposition were controlled by annual early spring herbicide treatments during the years 2009-2013 to selectively target this species with minimal impact to native plants. Finally, P release from sediments was managed during the year 2011 (application occurred during 15-18 June, 2011) using buffered alum-aluminate to drive algal productivity toward P-limited growth. The goal was to decrease internal P loading from sediment by at least 90% in order to reduce algal biomass and increase light penetration. The objectives of this interim letter report are to describe limnological conditions and aquatic macrophyte response in 2014 to overall lake rehabilitation
Activities & Recommendations
Grant Awarded
Grant ACEI-148-14 awarded
Control Invasive Species
Monitor Water Quality or Sediment
Monitor Pre and Post Treatment