Much-needed rain in the Great Lakes basin helped water levels recover somewhat this summer. Higher than average precipitation throughout most of the region in July left Lakes Erie and Ontario with above average water levels for this time of year, according to the most recent monthly water level report by the U.S. Army Corps of Engineers (USACE) Detroit District Office.
Despite the rain, the other three Great Lakes remain below their long-term averages. Lakes Michigan and Huron, the hardest hit by extreme low water levels this past year, received the least rain last month and remain 19 inches below their long-term average.
All of the lakes are now leveling off and beginning their normal seasonal decline through late fall and early winter. USACE forecasts Lakes Michigan and Huron to remain lower than normal for the next six months.
The extreme low levels earlier this year left many asking, “Where did the water go?” The answer is that it simply evaporated. The surface of the Great Lakes acts like an enormous evaporating pan under the right conditions. As explained in a previous post, the lack of ice cover in 2011-12 and record-breaking warm temperatures created ideal conditions for high rates of evaporation on Lakes Superior, Huron, and Michigan. These lakes had already been fluctuating below average levels for 15 years. A severe drought prevented the lakes from replenishing themselves, and water levels reached record lows.
Another reason the water levels on Lakes Michigan and Huron are lower than normal is the past dredging and erosion in the St. Clair River that resulted in a 10- to 15-inch (25- to 38-centimeter) lowering of water levels. These historic losses were never offset with mitigation measures. The only dredging that occurs today is to keep rivers at authorized depths for navigation. Recent studies show this is not the cause of low water.
Even though this is well documented by the agencies that have been monitoring water levels, going back to 1918, various theories about possible causes abound, especially online. Some of these theories and misleading facts get repeated so often, they become mythic. As the lakes begin their seasonal decline, a little myth-busting is in order.
Myth 1: Water levels are declining because companies are pumping millions of gallons of water from springs every day in northern Michigan, and it’s being bottled up and taken away.
On a recent Water Currents post on lake levels, commenter Bob wrote:
No mention is made about the companies that are pumping millions of gallons of water, “legally”, every day, out of springs in northern Michigan. These springs are connected to the lakes and yes the water is being “bottled up and taken away”.
Although groundwater extraction is an important concern for reasons that I won’t elaborate here, there is really no comparison with the amount of water lost through evaporation. John Lenters, a lake and climate scientist at the University of Nebraska–Lincoln, helped put some of these numbers in perspective in a previous post on the topic. “On average, Lake Superior loses 29 billion gallons of water PER DAY through evaporation,” he told me. His calculation is based on the annual average rate, but he notes that the daily evaporation rate can be ten times higher during the late fall.
The difference between evaporation from the largest of the five lakes and pumping rates in Northern Michigan is roughly a factor of 1,000 or more he says.
Myth 2: Water from the Great Lakes is secretly being shipped to China.
In a comment that was removed from this post due to other offensive language, someone wrote:
THE CHINESE ARE TAKING OUR WATER AND LEAVING US WITH THE [TOILET] WATER!! TANKERS WITH OUR FRESH WATER IN HUGE BLADDER-LIKE TANKS TO PUT INTO THEIR [AQUIFERS] THAT THEY HAVE ABUSED AND ARE NOW DRIED UP!!
Perhaps this is better categorized as a conspiracy theory. Its origins go back to concerns raised when opening the Great Lakes to international shipping in the 1950s. The myth is perpetuated today in the blogosphere and sometimes includes the detail that bladder tanks are being used to transport the water in the holds of ships bound for China.
All ships entering and leaving the Great Lakes must pass through the Great Lakes St. Lawrence Seaway System, where shipping traffic and cargo loads are closely monitored as ships pass through the lock system. In 2012, the Seaway Corporation logged 1,491 downbound transits through the Lake Ontario-Montreal section with a total cargo load of 18.9 million metric tons. According to the Seaway Corporation, traffic headed out the St. Lawrence River in 2012 carried 17,760 metric tons on average.
If water was secretly being shipped, these sea-going freighters would need to be converted over from carrying dry cargo such as grain, coal, and iron ore to be able to carry liquids such as water. Using the example from Lake Superior, even if each ship could carry 2.5 million gallons of water in bladder tanks, it would take more than 10,000 ships a day leaving Lake Superior to equal the amount of water lost to evaporation in one day. This would create quite a traffic jam at the Soo Locks!
Myth 3: Water is being diverted to the Mississippi River (or through a pipeline to western states).
On a recent post, commenter Peter wrote:
“Global warming causes low lake levels” ya and Santa is warming the north pole. It must not have anything to do with man made things, like a massive new water pipe line going into the southern states…
Water diversions in the Great Lakes basin are regulated by appropriate state, provincial and federal government authorities. The International Joint Commission (IJC) approves and provides regulatory orders for projects that affect levels and flows on the other side of the international border. I already busted this myth in a previous post but will summarize it again here.
Studies show that “the Chicago diversion is more than offset by a diversion into Lake Superior from Canada.” More water evaporates from the Great Lakes than flows over the Niagara Falls every year, according to the IJC. If there were a secret pipeline pumping water from the Great Lakes, it would have to be massive. I think someone might notice a project of this scale.
Myth 4: Just blame it on the weather (or Mother Nature).
Reader Peter also wrote:
Record low rain falls, and a climate that goes through cycles some of them thousands if mot millions of years old, (lo[n]g before man) and its impossible to know what cycle we are in…
It’s true that the weather plays a major role in water level fluctuations. The lakes respond rapidly to changes in weather, with the contrast between this year and last serving as an excellent example. Experts have been quoted blaming the weather for low lake levels in everything from this blog to the New York Times and in NBC News reports, but as described in detail in a previous post about how climate change and variability drive water levels on the Great Lakes, just blaming the weather is not the full story.
What is rarely mentioned is that these weather events, including more frequent droughts, warmer air temperatures, and even extreme weather events such as the flooding in the western portion of the Great Lakes basin this spring, are part of longer-term climate trends. There is no question that lake temperatures are warming and winter ice cover is decreasing. Both are consistent with global trends and are related to climatic factors that affect water levels in the Great Lakes. Given the well-documented trends in the region, it would be difficult to show that human-induced climate change is not having an effect on lake levels. There’s no denying that we humans share some of the blame.
Myth 5: There’s nothing that can be done.
In response to reader Peter and others, it’s true that there is no simple fix to the problem of extremely low (or high) water levels in the Great Lakes region. Not only is this the largest freshwater system in the world, the supply of water that sustains the lakes is affected by global climate change. A recent report by the IJC states:
Climate change poses new challenges for adapting to fluctuating Great Lakes water levels. Although the future is not certain, increases in temperature and alterations in patterns of precipitation are likely to affect water levels in the Great Lakes-St. Lawrence River system. There is strong evidence that in the future we will likely experience more extreme water levels – both high and low – that are outside the historical range experienced over the past century.
Further complicating matters is the fact that natural variation in the water levels is essential for maintaining a healthy ecosystem. Extended periods of extreme low or high water not only affect shipping and waterfront property, it also impacts sensitive fish and wildlife habitat throughout the region.
Current water control structures at the outlets of Lakes Superior and Ontario do very little in controlling the overall supply of water in the basin. Engineering or other solutions come with a big price tag and have yet to gain acceptance as feasible options.
Short of slowing or reversing global climate trends – something that would require a major societal shift away from fossil fuel dependence, which few people seem to be talking about – an adaptive approach to management of water levels is being promoted. Earlier this month, the International Joint Commission released a report and invited public comment on a proposal to establish an Adaptive Management Plan for the Great Lakes and St. Lawrence River Systems. The deadline for comments is August 31.
The record low water levels this past year provide a glimpse of what the future may hold for some of the greatest lakes on Earth. If this concerns you, read the IJC report, comment on its recommendations, and get involved with this and other Great Lakes restoration efforts aimed at finding solutions.
Lisa Borre is a lake conservationist, freelance writer, and avid sailor. With her husband, she co-founded LakeNet, a world lakes network, and co-wrote a sailing guide called “The Black Sea” based on their voyage around the sea in 2010. A native of the Great Lakes region, she served as coordinator of the Lake Champlain Basin Program in the 1990s. She is now an active member of the Global Lake Ecological Observatory Network.