The Ontario provincial government has announced plans to widen the runway at Billy Bishop Toronto City Airport to enable jet service, a move that a City of Toronto report says could diminish water flow in the Inner Harbour. The report, released on July 10, warns that the proposed expansion may curtail the natural circulation that helps flush sewage and other pollutants from the harbour, potentially affecting water quality.
Billy Bishop Airport currently accommodates turboprop aircraft, but the province’s proposal seeks a longer runway capable of handling larger jet planes. City officials examined how the physical changes to the airport’s footprint might alter wind patterns and water movement within the harbour. Their findings indicate that a reduced flushing capacity could leave contaminants in the water for longer periods.
The Inner Harbour, a central feature of Toronto’s waterfront, relies on regular water exchange to dilute and carry away waste. According to the city’s assessment, the runway widening could create a barrier that slows this exchange, thereby limiting the harbour’s ability to naturally cleanse itself. The report does not provide specific measurements of the anticipated reduction, but it emphasizes the importance of maintaining the existing flow to protect the harbour’s ecological balance.
Provincial authorities have not yet responded to the city’s concerns, and the project remains under review. The airport’s expansion is part of a broader strategy to increase air service capacity, but the city’s analysis highlights a potential environmental trade‑off that will need to be addressed before any construction proceeds.