OSWEGO — Water levels on Lake Ontario are declining steadily for the first time since March as warmer, drier weather continues and international regulators maintain record-high outflows.

The International Lake Ontario-St. Lawrence River Board (ILOSLRB) plans to maintain record-high outflows through the Moses-Saunders Dam, exceeding those prescribed in the much-maligned Plan 2014 water management strategy, in an effort to further drop the water levels on Lake Ontario and provide relief to shoreline property owners and municipalities.

The Lake Ontario water level is down nearly three inches from the record-high 249.08-foot mark hit on June 15. According to the most recent data from international regulators, Lake Ontario waters fell to 248.85 feet July 7, which is about 31 inches above average for this time of year.

Water levels first peaked June 6 at 249.08 feet and remained above 249 feet throughout the month of June, equaling the high water mark on three other occasions, before finally dipping below 249 feet July 1. Lake Ontario water levels continued to decline throughout the last week, dropping nearly 2.5 inches between June 26 and July 7. 

In a Monday press release, the International Joint Commission (IJC) — the bi-national body that oversees shared waterways between the U.S. and Canada — said ILOSLRB, which is overseen by the IJC, reached a consensus to maintain the roughly 367,300 cubic feet per second (cfs) outflows through the Moses-Saunders Dam.

ILOSLRB has decided to maintain record outflows for longer this year than during the last major flooding event in 2017. Officials said Monday the record outflows would be maintained until Lake Ontario water levels drop more than one foot and fall below 247.7 feet. 

Water level forecasts from ILOSLRB, which are based on historical water supply conditions from 1900 to 2008, indicate under average conditions the lake would fall below 248 feet by mid-August.

Outflows through the Moses-Saunders Dam have remained at or near record levels since mid-June, according to ILOSLRB data, and the net total supply of water entering Lake Ontario has dropped to around 321,000 cfs, far below the 431,200 cfs highs of mid-April and 390,900 cfs in late June.

ILOSLRB notified the shipping industry it plans to continue outflows above the normal safe navigation limit into the fall “to continue lowering Lake Ontario levels at an accelerated rate.” According to the IJC, mitigation measures have been implemented to allow safe navigation to continue at the higher flows, which are expected to continue to lower Lake Ontario water levels and provide relief from the high water.

‘The intent of (ILOSLRB) is to lower water levels as much as possible prior to winter,” the IJC said in a statement Monday. “It should be noted that (ILOSLRB) can only control outflows and not the water supplies to Lake Ontario. While the higher outflows will accelerate the rate of lowering that would otherwise occur, it is not possible, this year or any other, to lower Lake Ontario to a predetermined 'safe' water level by the onset of winter.”

Several outflow strategies above 367,300 cfs were considered, according to the IJC, which noted additional increases would require a shutdown of shipping on the St. Lawrence River between St. Lambert and Cape Vincent.

The economic costs of disrupting the supply chain of the Great Lakes-St. Lawrence economy is estimated at $50,000,000 per day, according to the IJC release, which also noted potential impacts to recreational boating, downstream shoreline property owners and wildlife habitats and breeding grounds.

Maximizing outflows beyond the current record-high levels would likely speed the short-term recovery of Lake Ontario, but the IJC said that strategy and the current record-high flows reach similar lake levels by the end of the year.

“Maintaining the current major deviation strategy will provide comparable benefit by the end of the calendar year, without creating $1.4 billion in economic damages,” IJC officials said.

Lake Ontario reached a record high of 248.05 feet in May 2017, following the adoption of Plan 2014. Two years later the record was surpassed when the lake reached 248.98 on May 31 before continuing to rise.

Shoreline property owners and elected officials have blamed the IJC and Plan 2014 for the high waters.

Plan 2014 was adopted by the IJC in 2016 and designed to protect against extreme water levels, restore wetlands and prepare for climate change. The IJC said the plan would return "more natural variations of water levels" to Lake Ontario and the St. Lawrence River to restore ecosystem health.

U.S. and Canadian commissioners said no water management plan could have prevented flooding this year, which the IJC attributes to heavy rainfall and inflows from Lake Erie.

The IJC, however, asked the Great Lakes-St. Lawrence River Adaptive Management (GLAM) Committee to expedite an ongoing review of Plan 2014. ILOSLRB plans to release a statement later this week describing the extents of the GLAM assessment.

More information on hydrologic conditions, water levels and outflows are available on the ILOSLRB’s website and Facebook page.

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