Madoc Sewage Lagoon Report - February 2026
The Madoc sewage lagoon has been a topic of interest for lake residents for a long time. The lagoon plays a vital role in managing wastewater discharge into Moira Lake. The MLPOA recently completed an extensive report reviewing current performance of the Lagoon, identifying critical gaps in testing, and recommending enhancements.
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Why It Matters for Moira Lake
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While the lagoon meets its mandatory Environmental Compliance Approval (ECA) limits for key parameters, it does not align with the voluntary Provincial Water Quality Objectives (PWQO) designed to protect lakes like Moira. The PWQO limit for phosphorus in lakes is 0.02 mg/L, while the lagoon can discharge up to 1.0 mg/L — 50 times higher and still be within ECA limits. Monitoring downstream of the discharge point shows frequent PWQO exceedances for phosphorus, and occasional ones for Carbonaceous Biochemical Oxygen Demand (CBODâ‚…).
These conditions are consistent with the nutrient enrichment (eutrophication) that fuels: algal blooms, aquatic weed growth, and sediment accumulation.
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Copies of the full report (79 pages), the Report Summary (13 pages) and a short briefing note (3 pages) are available below.