Briefings on St Lawrence Seaway Water Levels

Credit: Harry Valentine
Credit: Harry Valentine

Published Apr 22, 2020 6:51 PM by Harry Valentine

The international authority that overseas water levels along the St Lawrence Seaway between Montreal and Lake Ontario recently hosted briefings to explain the situation involving elevated water levels along waterways and lakes located upstream of Montreal. Among the objectives of The International Joint Commission is to prevent coastal flooding along the shores of major cities such as Montreal and Toronto.


Since prior to 1900, the American weather office has kept records of rainfall falling over the watershed region for the Great Lakes and St Lawrence River. Since 2018 and after, the office has recorded the highest levels of precipitation. Officials connected with the commission are undecided whether the recent increase in precipitation is a cyclical occurrence or whether it is the start of a long-term trend resulting from climate change. The City of Montreal is especially vulnerable as the confluence of the Ottawa River and St Lawrence River occurs to the west side of the city island.

A massive watershed region located to the north of the Ottawa River supplies water into that river, with the possibility that the increase in precipitation over the watershed area for the Great Lakes might have extended over the Ottawa River watershed area. During the spring of 2019, the Ottawa River overflowed and caused widespread damage to coastal areas. A hydroelectric power dam located on the Ottawa River between Montreal and Ottawa can serve as a control dam, except that water volumes result in the dam overflowing its sluice gates and requiring some upstream control of water flow rate.

Control Dams

The international commission that regulates water flow rate between Lake Ontario and Montreal along with the Canadian interprovincial commission that regulates water flow rate along the Ottawa River use existing hydroelectric dams to regulated water flow rate - except that the recent increase in precipitation has overwhelmed traditional methods of flow control. With regard to tributaries that flow south into the Ottawa River, prior to 1965 all hydroelectric power dams located inside the province of Quebec were privately owned. Nationalization of hydroelectric power opened the door for the provincial government to develop supersize hydroelectric dams to generate power for export.

While a few privately owned hydroelectric power dams once operate in Ontario, electric power generation is a part of a government monopoly. Governments prefer developing mega projects. Recent advances in small site and low-head hydroelectric power generation could allow for private development of such installations along many tributaries of rivers that feed into the Great Lakes, St Lawrence River and Ottawa River, provided that state and provincial governments were to allow and possibly encourage such development. The present regulatory regime is hostile to such development, even actively discouraging such development for environmental reasons.

Public Concerns

During the 2019 flood along the Ottawa River, citizens inquired about the ability to control water flow rate into the headwaters of the Ottawa River. Citizens also inquired about controlling water flow volumes from the Upper Great Lakes into Lake Ontario and the St Lawrence River; except that jurisdiction of water volume entering the Great Lakes and Ottawa River is outside of the jurisdiction of the international and interprovincial commissions that oversee these bodies of water. The inability of frozen ground to transfer spring-time melt-water into the water table is a contributing factor to seasonal flooding.

During the summer months, many of the regions that lie within close proximity to the tributaries which flow into the major rivers and lakes, experience low water table levels that require deep drilling to gain access to water to supply farms, villages and small towns. If the recent increase in precipitation is a long term development resulting from climate change and not a cyclical occurrence, Canadian provincial and American state authorities have jurisdiction to develop strategies to transfer massive volumes of spring flood water into the water tables, or encourage private citizens to do so.

Vessel Navigation

This year (2020), the St Lawrence Seaway opened for navigation at a later date than usual, a strategy to release large volumes of water downstream. At certain locations along the waterway between Montreal and Lake Ontario, higher volume water flow rate induces water currents that pose a danger to ship navigation and requiring the assistance of tug boats to tow ships through problematic stretches of river. To deal with 2019 flooding along the Ottawa River, the national minister of transportation suspended boat operation between Montreal and Ottawa until flood waters receded.

It is perhaps a forgone conclusion that during the 2020 navigation season, the COVID-19 virus lockdowns will affect ship traffic between the Gulf of St Lawrence and the Upper Great Lakes. Advances in artificial intelligence and related developments in autonomous vehicle operation would likely be adapted for application in vessels that navigate inland waterways, where coastal based telecommunications is within close proximity. Much American and Canadian economic activity depends on waterway vessels that carry bulk freight at much lower cost per unit of weight and per unit of volume that both and railway modes. 

Alternative Possibilities

During the public briefing, the commission was asked about alternative options to reduce water flowing from Lake Erie into Lake Ontario. Waterfront property flooding around the shores of Georgian Bay and Lake Huron prompted brief discussion about either restricting water flow from Lake Superior into Lake Huron, or even pumping water uphill into Lake Superior. Other options included diverting extra water from Lakes Erie and Ontario into the Erie Canal and Hudson River, pumping water from either Lakes Erie or Michigan into the Mississippi River and even from Lake Superior to Hudson Bay.

Based on a long-term trend in precipitation between 1900 and 2015, Canadian environmental activists have long opposed the transfer of water from Lake Michigan into the headwaters of the Mississippi River following the annual spring flooding along that river. It is presently unknown whether the recent post-2018 increase in precipitation over the Great Lakes and St Lawrence River watershed region is a cyclical or long-term event. If it is a long-term occurrence caused by climate change, transferring more flood water into the water tables and into other diversion channels may be future options.

Groundwater Sector

Several municipalities pump groundwater into overhead storage tanks to provide municipal water to their citizens. Many breweries, the bottled water industry, the soft-drink beverage industry and even farms also use groundwater in their production. The municipalities and industries that pump groundwater are usually located far from large lakes and far from major rivers. They are located near tributaries that flow into larger rivers and into lakes. During the annual spring flood season, frozen ground restricts the volume of water that soaks into the ground. Transferring floodwater into groundwater requires the installation of special piping.

Municipalities, farm groups and industries that pump for groundwater have the option of installing the special piping that could transfer large volumes of springtime floodwater into the local water tables. Their willingness to do so would provide the precedent as to how to do so successfully and provide a basis to implement such strategy across entire regions. It would reduce downstream seasonal flooding and if the increased precipitation is a long-term occurrence instead of a cyclical event, transferring excess water into the water tables would become a necessary strategy by which to manage future flooding.


The recent flooding along the St Lawrence Seaway and also around the shores of Lake Huron and Georgian Bay is the result of higher that usual precipitation and the need to restrict water flowing downstream from Lake Ontario. Uncertainty regarding the increase in precipitation restricts implementation of long-term strategies to reduce the severity of the flooding, such as various water diversion possibilities. If it is a long-term occurrence, Great Lakes state and provincial governments could encourage private transfer of flood water into the water tables and development of new private small-site hydroelectric power stations.

While the International Joint Commission may regulate water flow rate along the St Lawrence Seaway, the authority required to implement strategies to reduce the volume of water that flows into the Great Lakes and St Lawrence River is outside of their regulatory authority.

The opinions expressed herein are the author's and not necessarily those of The Maritime Executive.