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St. Lawrence River Water Levels – Spring 2017

April 14th, 2017 | Posted by Lee

St. Lawrence River Water Levels – Spring 2017

The snow and ice are gone, and the beauty of River this time of year is drawing us all to it – whether for a walk along its banks, or to the end of the dock. And boaters are anticipating the day they launch. However we get to the River, it’s pretty clear the water is higher than we’re used to seeing this time of year.

Naturally it leads to questions about why and what will the higher level mean for this summer?

Is the water level of the River higher than usual this year?

Yes and No

Yes – It is a little more than 18” above its recent (1918 – 2016) average for this time of year and about 6” higher than last year.

No – Not in the bigger picture. The River is actually around 6” below the level it would be if were undammed and still allowed to run unobstructed.

Why are water levels higher than last year?

The water in the St Lawrence is higher than last year because the supply of water flowing into the river has been greater.

The River is not an isolated water body, it is part of a large, complex system. When looking at the level of the River, it is important to look at where its water comes from and the other factors that influence levels. It is fed by the outflow from Lakes Ontario and Erie, snowfall, and rainfall and runoff. And at times it must be controlled due to conditions on the lower river below the Moses-Saunders Dam.

According to the International Lake Ontario-St. Lawrence River Board,

A series of storm events passed through the Lake Ontario-St. Lawrence River system from April 4-10, resulting in significant precipitation across the region. Some eastern parts of the Lake Ontario basin received as much as 3.2” (80mm), while areas around the St. Lawrence River near Montreal saw as much as 3.5” (90mm) during the same series of events. . . The wet conditions have resulted in rapidly rising water levels throughout the Lake Ontario and St. Lawrence River system. . . To prevent . . . levels from rising further and causing more extensive damage [below the dam], the International Lake Ontario-St. Lawrence River Board reduced outflows from Lake Ontario in accordance with Plan 2014.

What is Plan 2014 and what does it have to do with water levels on the St. Lawrence River?

When the Moses-Saunders Dam was built in the 1950’s it meant the St. Lawrence River no longer ran wild and a plan for managing its levels and flows had to be developed. That plan – Plan 1958DD – in operation for over 50 years, led to the loss of 64,000 acres of wetlands, the destruction of critical habitat and the decimation of key species like Black Tern and Northern Pike. In the 90’s it became clear a new plan was needed to stop the slow death of the River.

A new plan – Plan 2014 – was implemented just this past January after years of study, community input and review by the governments of Canada and the United States. It is intended to set water levels more in tune with the natural conditions.

By allowing for a more natural cycle of high and occasional low water, Plan 2014 will improve the overall health of the River and restore critical wetland habitat and species, and provide greater economic opportunities for the River region’s tourism-based economy. This Spring’s water levels are on track with Plan 2014 and should begin to have positive results.

What will Plan 2014 mean for water levels in the future?

Water levels have and will always fluctuate. It is important to understand that while we on the River tend to like our water levels to be on the higher side, the health of the St. Lawrence depends on having a variety of levels including some infrequent low levels. In a very few years, likely 6 or fewer years per century, levels will drop below the long-term average when water supplies to the River are naturally lower. These occasional low levels are essential to the health of the fish, the wildlife and the wetlands of the St. Lawrence River.

Will Plan 2014 mean a longer boating season?

Most of the time yes, but not always. Overall, it’s clear that Plan 2014 will extend the boating season. Over the last hundred years, the boating season under Plan 2014 would have been 23 weeks or longer in 51 out of every 100 years.

Click here for more information on Plan 2014

Click here for more news from the International St. Lawrence River Board of Control

Please consider becoming a member of Save The River to support our education programs and advocacy for a healthy St. Lawrence River –

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