Manipulating Great Lakes Water Levels

By Dan MacFarlane

Daniel Macfarlane is an Associate Professor in the School of the Environment, Geography, and Sustainability at Western Michigan University.He is also a senior fellow at the Bill Graham Center for Contemporary International History, University of Toronto, and President of the International Water History Association. His research and teaching focus on the Great Lakes-St. Lawrence Basin. Macfarlane is the author or co-editor of six books, including Natural Allies: Environment, Energy, and US-Canada Relations (forthcoming August 2023) and The Lowest Great Lake: An Environmental History of Lake Ontario (forthcoming 2024).

In the first essay, Macfarlane discussed the role of the International Joint Commission in fostering harmonious relations between the U.S. and Canada regarding their boundary waters.

Environmental and energy issues have always been key to US-Canada relations and diplomacy – that is the central point of my new book Natural Allies: Environment, Energy, and the History of US-Canada Relations. Going back to the nineteenth century, no two nations have exchanged natural resources, produced transborder environmental agreements, or cooperatively altered ecosystems on the same scale as the United States and Canada. In this post, the second in a series that draws from Natural Allies to highlight transborder issues that concern the Great Lakes, I will address water levels and diversions.

Over the last century and a half, the United States cooperated to radically engineer water environments in the Great Lakes-St. Lawrence basin. The Chicago Sanitary and Ship Canal was the first large-scale diversion out of the Great Lakes basin. Opened in 1900, this engineered waterway reversed the flow of the Chicago River away from Lake Michigan. The volume of water taken out is referred to as the Chicago Diversion (which for most of its history has been held at well under its maximum capacity of 10,000 cubic feet per second).

The outflow of Lake Superior was dammed and regulated not long afterward; Lake Ontario is the only other Great Lake that was dammed and officially regulated (in the 1950s as part of the St. Lawrence Seaway and Power Project). The International Joint Commission, covered in the previous post in this series, regulates the levels of these lakes. Lake Erie is partially affected, though not officially regulated, by the Niagara remedial works and power diversions. There has been talk of doing the same for Lake Huron by installing works in the St. Clair River, which would affect Lake Michigan as well.

Between the late nineteenth century and the early Cold War, Niagara Falls was progressively modified to create both power and beauty. Diplomatic talks to create the St. Lawrence Seaway and Power Project finally came to fruition in the 1950s, which is when the Niagara River Diversion Treaty also took effect.

Scientific understanding of “natural” lake levels evolved during the Cold War. By then, engineers and government experts had acquired a more solid understanding of the causes of Great Lakes fluctuations. The IJC completed several reference studies on Great Lakes water level issues. The IJC advised the governments in its landmark 1976 report Further Regulation of the Great Lakes that protection against high and low levels was best achieved through systematic management using all the tools available. IJC studies contended that the high economic and environmental costs did not justify the benefits of further artificial regulation of the other Great Lakes. 

In 1985, the IJC finished a report on consumptive water uses and diversions. This study demonstrated that consumptive uses (agricultural irrigation, bottled water, and other packaged beverages), which had not been considered significant because the volume of water in the system is so large, could collectively have a noticeable impact. In fact, these cumulative “death by a thousand straws” scenarios potentially withdrew more water from the lakes than diversions. 

However, the 1985 study also concluded that climate and weather affect levels of the lakes far more than existing anthropogenic diversions and uses, recommending that the governments not consider the manipulation of existing diversions to either intentionally raise or lower levels. The IJC’s final recommendations in a 1993 report included a range of actions, such as promoting shoreline management measures, but recommended against further attempts to regulate the Great Lakes. 

These studies also showed that engineering interventions in the Great Lakes-St. Lawrence Basin had cumulatively lowered water levels by several feet, but natural forces were still the prime determinant. Depending on which lake one considers, the maximum range of water level fluctuations has only been about four to seven feet in the 150 years since records have been kept. 

Emboldened by the various water megaprojects built in the early Cold War, such as those in the Niagara and St. Lawrence Rivers, engineers had promulgated even bolder water control plans that involved the bulk export of water, especially to the US Southwest. The two most infamous are NAWAPA and GRAND. 

Wary of new water diversion threats, the US Great Lakes states, along with Ontario and Quebec, signed the Great Lakes Charter in 1985. Any plan proposed in any Great Lakes state or province that involved new consumptive uses or diversions had to give prior notice to, and seek the approval of, all other states and provinces. However, this Charter was a non-binding good faith agreement, and holes soon appeared. For example, the possibility of bulk exports out of the Great Lakes basin surfaced (e.g., the Nova Group in 1998 proposed sending Great Lakes water by tanker to Asia). 

The 2001 Annex to the Great Lakes Charter committed the parties to develop binding regulations to ensure no net water loss through diversion or consumption – or through adverse impacts on water quality. In 2005 the Great Lakes-St. Lawrence River Basin Water Resources Compact was forged amongst the Great Lakes states and the federal government, coming into effect in 2008. The Great Lakes-St. Lawrence River Basin Sustainable Water Resources Agreement, which added Ontario and Quebec, was also inked. Though the American compact has the force of law, the companion agreement involving the two Canadian provinces is non-binding. 

These two accords banned new or increased water diversions out of the Great Lakes-St. Lawrence basin, with some strictly controlled exceptions. The states and provinces party to the accords also pledged to use a consistent standard to review proposed uses of water and withdrawals, including consumptive uses within the basin, as well as develop and implement water conservation and efficiency programs. 

This was a major improvement. But concerns remain. For example, there are legitimate worries that under international trade accords, such as NAFTA and its successor, efforts by governments to protect and conserve their water resources might be ruled as discriminatory practices. That the recent compact might also commodify water worries some, as does the fact that it does not limit the export out of the basin of packaged water or beverages in containers smaller than the average office water cooler. Plus the Chicago Diversion was lamentably grandfathered in.

But the upside is that there is a more watertight legal system for preventing most types of diversions out of the Great Lakes. This is especially timely since climate change is fueling droughts in more water-scarce areas of the continent, increasing the likelihood that those regions will come calling for Great Lakes water.