District’s Community Planning Services Committee held a special statutory public meeting in May regarding proposed changes to Muskoka’s Official Plan which, if approved by District Council, will add five new lakes to its list of vulnerable lakes in Muskoka.
The lakes to be added due to confirmed blue-green algae blooms in 2021/2022 are Fawn Lake in Bracebridge and Huntsville, Mary Lake in Huntsville, Menominee Lake in Lake of Bays and Huntsville, Muldrew Lake in Gravenhurst and Paint Lake in Lake of Bays. Other lakes which also experienced algal blooms are already on the list, noted District Planner Brittany Manley.
The proposed amendment would also remove Barron’s Lake in Georgian Bay from the list because it no longer shows a long-term trend of phosphorus concentrations over 20 micrograms per litre.
The District determines lake vulnerability from a recreational water perspective when:
- There is a long-term statistically significant increasing trend in total phosphorous concentrations;
- A long-term total phosphorous concentration of greater than 20 micrograms/litre and
- A blue-green algae cyanobacteria bloom, confirmed and documented by the province and/or public health.
Water bodies included on the list are subject to the District’s enhanced protection policy. To be removed from the schedule, “it has to be demonstrated that total phosphorous indicators are not present for three years of monitoring, if applicable, or a causation study concludes that development is not the primary cause of the water quality indicators presence,” said Manley.
Protection policies—such as increased building and septic system setbacks, a site-specific soil investigation, construction mitigation, and other requirements at the lower-tier municipal level such as a development impact study on a vulnerable lake—have already been put in place for the lakes that experienced a bloom in 2021/22. Adding them to the schedule will simply reinforce the approach, explained Manley.
The five lakes to be added would bring the total list of lakes considered vulnerable from a recreational water perspective in Muskoka to 22.
The District is currently concluding five causation studies undertaken in 2021, which may change the approach for determining lake system health. “Staff anticipate that the results will provide a watershed perspective that may lead to other recommendations, including a more comprehensive policy review of the lake system health and causation study policy,” she added.
Feedback received at the time of the meeting included support for including Fawn Lake in the OP amendment and a future causation study. Concern for algal bloom on Muldrew Lake and ensuring it does not become a reoccurring problem. Another comment involves the District’s causation studies and lake health programs and the need to revise current programming in light of the effects of climate change as well as a question regarding the monitoring process for lakes listed as vulnerable and site alteration regulations. The following correspondence was shared at the public meeting (pdf).
Anyone wishing to make comments on the proposed amendment can do so before it’s voted on by District Council. For further information or to provide a comment contact Brittany Manley at brittany.[email protected] or by telephone at 705-645-2100 x4122.
The lakes in yellow are already on the vulnerable lakes list, the lakes in green are proposed to be added and the lake in red is proposed to be removed.
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