With a long-standing commitment to protecting recreational water quality within the local watershed in their Official Plan, the District Municipality of Muskoka needs to keep their models and planning policies current. To do so, they retained HESL to complete an update and revision of the program recommended by Dr. Hutchinson (then with Gartner Lee Ltd.) and adopted by District Council in 2006.

The update and revision of the original program involved:

• Revising the model to reflect changes in the scientific basis and assumptions.
• Updating the water quality records for the 160+ lakes in the model and testing for trends in concentrations.
• Comparing the model predictions to the measured water quality records.

When we concluded that the model was not reliable, we advised discontinuing use of the model for lake management and developed new Official Plan policies for water quality protection. 

We recommended that planning policies should:

• Place greater emphasis on the excellent long-term record of water quality measurements maintained by the District.
• Provide for lake-specific “causation studies” in response to measured changes in water quality instead of the previous phosphorus-centred approach favoured by the Province.
• Implement higher minimum standards and Best Management Practices for development or redevelopment on all lakes to protect all aspects of water quality and aquatic and terrestrial habitat.

The June 2019 update to the Muskoka Official Plan saw adoption of all HESL planning policy recommendations. The District Municipality of Muskoka implemented the newly revised program and actively uses it, per our recommendations. Water quality remains stable and excellent.