The lake and its shorelines
The Ministry of the Environment, Conservation and Parks confirmed a blue-green algae bloom on Leonard Lake on September 28, 2018, which led to the lake being classified as vulnerable in the Muskoka Official Plan and to a District causation study (District Municipality of Muskoka, n.d.-c). The District reports that the studies found development was not the cause of the reported water quality indicators, that the primary cause of the reported bloom was climate change, and that the lake has been removed from the vulnerable list (District Municipality of Muskoka, n.d.-a).
The District scheduled Leonard Lake for water quality monitoring in 2025 (District Municipality of Muskoka, 2025). The Muskoka Watershed Council’s 2023 report card gives it an average total phosphorus of 5.9 µg/L for 2001 to 2022, and grades its phosphorus trend “Not Stressed” (Willison, 2023). None of the 36 conservation authorities in Conservation Ontario’s directory is named for Muskoka (Conservation Ontario, n.d.); the District monitors lake water quality through its Recreational Water Quality Monitoring Program, part of its Lake System Health program (District Municipality of Muskoka, n.d.-b).
Which municipality a property sits in also matters day to day: it sets the zoning, issues building permits, and sets the municipal share of property tax. On Leonard Lake that is the Township of Muskoka Lakes.