The following is a press release from the International St. Lawrence River Board of Control:
Lake Ontario levels have been dropping rapidly compared to average rates through the months of June and July. The Board has been releasing the unprecedented outflow of 10,400 m3/s (367,300 cfs) since 14 June and, despite wet conditions, Lake Ontario levels have fallen 30 cm (12 in.) since peaking in late May. Lake Ontario levels remain above the IJC’s high level threshold and the Board will continue releasing high outflows with the intent to provide all possible relief to Lake Ontario shoreline riparian interests, while balancing the impacts on other affected stakeholders on the St. Lawrence River.
The Board met on 1 August 2017 to assess current and forecast hydrologic conditions. Total inflows to Lake Ontario have remained very high for this time of year, as have Ottawa River flows into the St. Lawrence River. Levels of Lake St. Louis (near Montreal) set a new record high for the month of July and remain close to record levels for this time of year. Since water levels on Lake St. Lawrence decrease with higher outflow from Lake Ontario, the unprecedented outflow from the Moses-Saunders Dam have resulted in well below average levels on Lake St. Lawrence. Furthermore, as water levels on Lake Ontario decline and the outflow remains at 10,400 m³/s, velocities in the upper St. Lawrence river will increase resulting in hazardous conditions for shippers and recreational boaters.
Given these conditions, the Board discussed current and future outflows from Lake Ontario. The Board understands that high water levels and high outflows continue to impact the public and businesses on Lake Ontario and the St. Lawrence River. Currently the impacts of falling levels and increasing current velocities in Lake St. Lawrence and the St. Lawrence River are increasing as Lake Ontario levels drop. In the interest of providing all possible relief to riparian owners, while balancing the safety risks associated with increased current velocities, outflows from Lake Ontario will need to be gradually reduced in the near future.
The Board, in consideration of impacts to public water uses, riparian landowners and businesses, commercial shipping and recreational boating will maintain the current record outflow of 10,400 m3/s (367,300 cfs) until 8 August, providing conditions remain safe. However to maintain safe conditions in the system, the outflow is expected to be reduced to 9,910 m3/s (349,970 cfs) on or before 8 August. This new outflow will be a record high for that time of year to provide all possible relief from high water levels in Lake Ontario while balancing the impacts downstream. Water levels are expected to continue to decline rapidly into the fall throughout the system, and outflows from Lake Ontario will remain high. The Board, in conjunction with its staff, continues to monitor and reassess conditions on an ongoing basis.
