Hydrology: Everything You Need To Know About Lake Erie’s High Water Levels

The Lake Erie shore has been a victim of high water levels over recent years. Floods have occured occasionally in the last century, but their occurrence has been steadily increasing over the years. In the winter of 2019-2020, Turkey Point and other Lake Erie shorelines were flooded nearly half a dozen times.

Flooding on the shoreline is due to a combination of high winds and high resting water levels. High winds cause the lake to slosh, from one end to the next until the water is returned to normal. High winds have been a common occurrence on the Lake forever; they come and go, but high winds with a combination of high-water levels can cause issue on land.

Graphic showing Great Lakes water balance components.
Figure 1.1 - Source: US Army Corps of Engineers

High water is caused by high inflow or low outflow - or a combination of the two. These categories have multiple contributors, which leads to a more length and complex explanation found throughout the remainder of this article.


According to the Great Lakes Commission (GLC) 79% of the Lake Erie's water flows in from the St.Clair Lake and Detroit River. The remaining inflow into Lake Erie is comprised of direct precipitation and runoff which account for 11% and 10%, respectively. 

Inflow from the Detroit River

The Detroit River transports water from Lakes Superior, Michigan-Huron and St. Clair into Lake Erie.

According to US Army Corps of Engineers (USACE), Michigan-Huron, St. Clair, Erie & Ontario are 11, 6, 6 & 3 inches higher respectively than they were at this time last year, and 36, 34, 32 & 19 inches, respectively, above their long term April average. Lake Superior is down 1 inch since this time last year.

Lake Superior and Lake Ontario are the only two lakes with regulated outflows via manmade structures and modification of these flows require approval by the International Joint Commission (IJC), who has a record of being sued for mismanaging water flows. The IJC has commissioned two water regulatory plans which include Plan 2012 and Plan 2014 which were put into place to help regulate the outflows of Lake Superior and Lake Ontario, respectively. These plans mainly focus on restrictions, making it more difficult for outflows to take quick effect on lake levels, in hopes of inducing said benefits.

The other lakes' outflows are mainly governed via the hydraulic characteristics of the outlet rivers. River hydraulic characteristics are dynamically change during high flow periods and over time. Dredging and piers have been incorporated into outlet rivers to help decrease this variation. There are also various major and minor diversions around the Great Lakes which have uses that range from municipal use to water travel (canals).

Referencing the lake levels in 2020 as of May, it can be noted that 4 Lakes have rising levels - some more extreme than others. Lake Superior is the only lake that has shown negligible water level increases to date. Instead, Lake Superiors water levels are maintaining, and occasionally dropping. Recall Figure 1.1 where evaporation and outflow are the main two methods of removing water from a body of water. Surely from January to April there hasn't been much evaporation in Lake Superior. Instead, aggressive outflows are the only possibility. See diagram below.

Figure: Lake Superior Water Balance. Source: GLISA 2014.
Source: National Geographic

A 2018 article by the Chicago Tribune reports, "Last year, the amount of water released from Lake Superior into lakes Michigan and Huron was the highest in 32 years." Looking at the reported outflow rate below, you can see the current outflow is 330 cubic metres per second or 87,000 gallons per second above the average.

Source: International Lake Superior Board of Control

The regulation plan of Lake Superior outflows is administered by the International Lake Superior Board of Control. In summary, the plan set by the IJC requires that Lake Superior to not rise above 602 feet above sea level. At the time of writing, Lake Superior is at that maximum and because of legislation set forth by the IJC, the lake is forced to increase flow into Lake Michigan-Huron. Perhaps a more detailed outflow equation is required to regulate the flows to have less negative effects downstream.

It is interesting that flows are set by a function of Lake Superior's levels and not Michigan-Huron's levels, which is the receiving lake. It would make sense for the flows to be set based on a function of lake levels downstream and work towards keeping annual averages consistent among the more populated lakes.

Adjusting the rate of outflow with a new formula is the long term solution, but mild tweaks will take years to see effects downstream. The outflow of Lake Superior will need a more dramatic reduction for the short term and then be followed by a new formula for the long term.

Source: IJC

If Lake Superior cannot handle their water levels and the IJC is unwilling to loosen constraints, the Long Lac diversion and the Ogoki diversion (both of which were built to push water from the Hudson Bay to Lake Superior) could be throttled, blocked or reversed to help protect the Great Lakes by reducing the overall inflow into the water course.

The Waboose Dam, which spans 1700 feet (which is 450 longer than the Hoover Dam for visual reference), was built by Ontario Power Generation. The Ogoki River naturally flows into James Bay (part of the Hudson) but the Waboose Dam was built to divert water into the Great Lakes to fuel the hydroelectric plant at Niagara Falls via Lake Nipigon. The Ogoki River flows at a rate of 4,273 cubic feet per second.

The further you analyze upstream, the more problems unravel, such as the flows from James Bay but that's more of a concern to those managing Lake Superior's inflows. Ideally restricting outflow at Lake Superior would be in best interest for downstream lakes Michigan-Huron, St. Clair, Erie and Ontario and a great first step towards a solution.

According to the Manitoulin Expositor, "The Georgian Bay Great Lakes Foundation asserts that the IJC has ignored similar outcries from several sectors over the last 14 months to push for cutting back inflows from the Long Lac and Ogoki Diversions. The Ontario government cut back inflows from these diversions in 1952, 1973 and 1985 in reaction to public outcries in previous high water periods."

Note that in the above figure, record-high Lake Superior outflows were set in 1951 and then the government responded in 1952 by restricting diversions. The government has shown throughout history they are capable of responding to and aiding with a solution to high water levels in a timely manner.

Surface Runoff

Surface runoff accounts for 10% of the inflow into Lake Erie. Surface runoff has been increasing steadily due to increased urbanization. Urbanization changes areas that were once permeable into non-permeable surfaces such as buildings and roadways. Non-permeable areas do not encourage infiltration into the soil and the water which would have previously infiltrated into the groundwater is introduced into the local stormwater control system (ie. storm sewer, swales and/or tributaries). The excess water then travels through the control system to the ultimate receiver.

When developing new subdivisions each county has their own municipal engineering regulations which the development must be in conformance with before breaking ground. The majority of counties require that the post-development stormwater runoff flows do not exceed the pre-development flows. The most common method to accomplishing this is by implementing a stormwater management pond to store the water and release it at a controlled rate. The downside to this method is that the pond simply stores the excess water and then releases it into the ultimate receiver at a controlled rate over an extended period of time which actually increases the flow into the ultimate receiver from the newly developed area. Other stormwater management practices that are being developed to help promote increased site infiltration and reduced runoff are infiltration basins, bio-swales and pervious pavement. Increased runoff is a large factor in the increased lake levels and perhaps counties need to adjust their regulations when it comes to managing stormwater within proposed developments.

Given these smaller watersheds are relatively close to the lake, they're fuelled by similar precipitation as to what the lake receives, as discussed below.

Direct Precipitation

Many people are under the perception that the recent high-water levels are due to increased precipitation in the area. According to the Great Lakes Commission only 11% of Lake Erie’s inflows are due to direct precipitation. This section will analyze whether there has been increased precipitation within the Great Lakes region over the past decade.

On the West end of Lake Erie, we have Leamington. The figure below outlines the quarterly (seasonal) precipitation in the Leamington area from 2015 to 2020. The yearly data was not used because it is only halfway through the year and the total precipitation in the year of 2020 was shown to be significantly lower than average. Referencing the total precipitation graph for Leamington there is not significant evidence to justify an increase in precipitation in the first quarterly.

Leamington annual precipitation. Source: WeatherStats.ca

The seasonal precipitation data was also analyzed for City of Welland which is located on the east end of the Lake. Similarly, to Leamington there is not sufficient evidence to justify an increase in precipitation within the region over the first quarterly.

Welland annual precipitation. Source: WeatherStats.ca

Looking around the Great Lakes' watershed, even as far North as Sault Ste. Marie, there is not sufficient evidence that rainfall is significantly increasing to result in such drastic, yet constant water level increases.

In conclusion, there are no obvious patterns for significantly increased precipitation around Lake Erie.


According to USACE, the outflow from Lake Erie is not regulated, but instead, controlled exclusively by the hydraulic characteristics of the outlet rivers, being the Niagara River and the Welland Canel. The Niagara River accounts for about 95% of the outflow, while the Welland Canal is responsible for the remainder.

By adjusting the hydraulic characteristics of the main outflow (the Niagara River), river engineers are able to increase or decrease the outflow. Controlled diversions are another option to increase and regulate outflows, which are often proposed. To those who argue river outflows cannot be modified, recall in 1887 when engineers not only modified the flow of but rather entirely reversed the flow of the Chicago River. You can view the entire appendix of all hydraulic modifications including dredging and construction on the USACE website.

In 2019, there was a proposed diversion to route 7 million gallons a day to Wisconsin. It was claimed that the Chicago River dropped the lake levels 2.5 inches alone and "a few more diversions the size of the Chicago River could drop lake levels a foot." These diversions would require regulation (which we have no shortage of within Lake Erie) to ensure the proper outflow rates. When water levels sufficiently drop, these outflows could be restricted. The more controllable diversions a lake has, the more controllable the water levels will be.

The International Control Dam is operated by Ontario Power Generation and controls the water diversions from the Niagara River and dispatches the water between the New York Power Authority and Ontario Power Generation. This dam must ensure enough water flows over Niagara Falls such that a solid curtain of water is always shown and is obviously capable of increasing or decreasing flow over the falls.

In addition to diversions and the International Control Dam, engineers mention how the hydraulic characteristics of the Niagara River control the outflow via the Niagara River. This above figure is an example of how outflows are restricted on the Niagara River. West of the I-190 there are piers in the Niagara River. We are not suggesting for these piers to be removed (and this is just an example for your education) but we are suggesting that engineers are correct when they say flows of the Niagara River are managed via the hydraulic characteristics of it.


Myth 1: Lake Erie's high water is due to climate change and rising sea levels.

First and foremost, we are located on Lake Erie, not the sea. Melting glaciers from the poles do not affect the inflow to Lake Erie. However, the melting ice does cause the ocean levels to rise which are rising at a rate approximately of 3mm per year. This means that it will take 8 years for the average sea level to rise 1 inch.

Compare a 1-inch increase in sea level due to climate change to the last 8 years of lake levels, which have jumped several feet, and the effect of climate change on the lakes can be assumed to be negligible.

The Great Lakes are also significantly above sea level with Lake Erie being approximately 175 meters above sea level. Ultimately, the significant difference in elevation means that Lake Erie is not affected by an increase in sea level.

Climate change is a slow and consistent change, and what we're experiencing on the Great Lakes is neither of that. Nonetheless, Prime Minister Justin Trudeau chose to take this opportunity to attack the opposition on a core value of his party instead.

It's convenient for politicians to play the climate change card, but I think most people can see through their agendas after looking at the data.

Myth 2: This is due to excessive rainfall.

Occasionally the water levels rise due to heavy rainfall. Rainfall causes high runoff, which attributes to a small fraction of a lake's inflow. While it is indeed true that high water levels are caused partly by high precipitation, it is not the core reason. High water levels are due to a combination of increased inflow from watersheds, runoff, and precipitation.

Here we have annual total precipitation data for Norfolk County, courtesy of Environment and Climate Change Canada. Norfolk County was chosen because of its centralized location on Lake Erie’s shoreline.

The above figure shows the precipitation by year in Norfolk County. The last 5 years have not had significant or abnormally high annual precipitation. It can be seen that precipitation fluctuates by year and there is no significant correlation to an increase in annual precipitation within the Norfolk County region over the past decade.

However, the data on the lake levels can be referenced below, courtesy of the USACE. It's quite clear that from approximately 2014 onward, lake levels began rising steadily. Ultimately, the precipitation data doesn't reflect the significant increase in lake water levels.

I can't blame some of those who argue high precipitation because some newspapers with mild credibility report such, but what they don't say is while rain causes an increase in the short-term, it is insignificant in the big picture.

For example, if the lake were to rise 20 inches over a 6-month period, 2 inches could be from rainfall and 18 inches from other sources. It is factual for a newspaper to report the lake is rising due to rain. Their claims are not false, but they are deceiving to the reader.

In conclusion, after looking at the graphs above there is not significant evidence to support the long-term correlation between precipitation and lake levels.

Myth 3: Inflows and outflows cannot be controlled.

If inflows and outflows couldn't be controlled then there wouldn't be so many governing committees. This article has set forth a number of mechanisms to govern and modify lake levels.

Myth 4: The water used to be higher back in the 1980s.

Thankfully the US Army Corps of Engineers has the data to knock this myth down too. In their latest bulletin:

Lake Erie continued its seasonal rise from February to March, rising about 2 inches to a level of 573.98 feet. This level was a new record high monthly mean water level for March, surpassing its previous record set in 1986 by 3 inches.

The levels have now surpassed those levels from 1986, so this is simply no longer true.

More importantly, what happened in the 80s? Public outcry. The people spoke up, the government made changes and things went back to normal until the government decided to push the envelope again. This brings us here.

Myth 5: Water levels are high so that freighters can ship easier/cheaper.

We took this question to marine engineer Bernie Johnson, who is currently the Director of Special Projects at Algoma Central Corporation and has decades of experience leading the build of ships around the world.

"It tends to be a double-edged sword with water levels. When levels are high you would think you could load deeper but there are almost always river and lock transits that limit draft. Also, increased water tends to increase flow in the rivers which is another negative. I actually know of a port that was closed due to high water flow for a couple of weeks last summer. Outside of possible dock or shoreline or current flow issues associated with high water, I would think the ports would be relatively neutral about this on the great lakes." he concluded.


While precipitation, runoff and climate change have effects on water levels, the increasing water level on Lake Erie since 2014 is largely due to legislation set forth by the IJC which forces the International Lake Superior Board of Control to release more water into Lake Michigan-Huron. Since water levels are a complex problem, made of many attributing factors, we can't blame the high levels entirely on Lake Superior, but we believe it's the easiest and most controllable and actionable next step.

What's Next

High water has been a problem many times in the past, and generally government has responded once there was sufficient public outcry. We must call out myths the government chooses to feed the population, and educate those around us. We cannot let the government tell us what they want us to hear, but instead resort to the facts. We must see through their political games and excuses. The water levels in Lake Erie are controllable.

Additional Reading

Data compiled by author Josh MacDonald. BSc, University of Toronto. Edited by Brett Pond. W.Eng 4th-Year Student, University of Guelph