Lake Ontario outflows being reduced, no further shoreline damage expected

Aug 23, 2019

The international board that helps manage water levels on the Great Lakes announced it is reducing outflows. This means the International Joint Commission's International Lake Ontario-St. Lawrence River Board will be letting less water from Lake Ontario through the Moses-Saunders Power Dam into the upper St. Lawrence River.

Record high water levels flooded homes and businesses, knocked down seawalls and tore up docks this summer. The IJC set record high outflow rates for more than two months.

On Wednesday, though, it slowed those rates to give some relief to commercial shippers. Andrew Kornacki, a communications officer for the board, said it has been able to reduce outflows because the water is going down in the lake.

"This is the natural progression of water levels on Lake Ontario," he said via phone. "You see them rise in the spring, level out in summer, declining in the fall and into the winter, so you’re seeing that seasonal decline."

Typically the board has to balance the needs of people upstream and downstream when deciding how much water to let out. Kornacki said reducing the outflows will lower the velocity of water flowing through the channel, which is important.

"Not just for shipping, but also for recreational boaters, people using that waterway, people swimming in it," he said, "and the impacts that it would have to riparian shoreline owners to ensure that velocity wouldn’t do further damage downstream."

“There’s been a tremendous amount of impact to the commercial navigation and the supply flow chain to the tune of roughly about $280 million to date," said board member Tony David. "There have been speed and vessel restrictions imposed during the higher outflows."

The board is reducing the outflows by about 10,000 cubic feet per second, which adds up to about a centimeter over the course of a week. Water levels on Lake Ontario have dropped 10" in the last month and are expected to drop by another foot by mid-September.