Great Lakes water levels

The other night on the telephone I was asked about the water levels in the Great Lakes. As anyone in Michigan or other states on the Lakes knows, the water levels have been down significantly in recent years.

I answered that I didn’t know for sure, but that we’ve had a lot of rain (which obviously puts more water into the lakes and into the rivers and streams which empty into the lakes) and more overcast days and cooler temperatures than we have in the past couple of years (which limits evaporation).

I said that the biggest reason I suspected a significant rise in lake levels was that I haven’t heard a single word about it in the local papers. And I added that it must be up more than a little, or else we’d be hearing about how the water level was up but “not as much as expected”.

Well, a quick google gives us this:

I live near Lake Michigan. As you can see, the level of Lakes Michigan and Huron (green line) are up almost 3/4 of a meter (2 or 2.5 feet) over the level from last year at this time.

As this long-term chart shows, the variance on Lakes Michigan and Huron is about four feet or so, from 176.0 to 177.2 meters. The long-term mean (1900-1990) is about 176.6 and we’re currently sitting at about 176.3, with somewhere around 176.1 overall for the year. (I’m eyeballing it from the charts so cut me some slack.)

In other words, we’re running a little low but it’s nothing to get excited about. As the historical chart shows, virtually all of the 1970s, 1980s, and 1990s were well above the historical levels. So when the pendulum swings the other way (as it’s bound to do from time to time) no one younger than 40 years old even remembers the lake ever down where it’s been for the past couple of years.

In 1998 or 1999, when the levels were down, a co-worker about my age who also runs a charter fishing boat on Lake Michigan was complaining about needing to get his boat slip dredged. He thought it was the end of the world and that it wouldn’t be long until there wasn’t any more fishing on Lake Michigan due to lack of water access. I pointed out that things were bound to come back, and that levels had been higher than normal for decades, leading marinas to expand based upon extraordinary levels instead of prudent averages.

“Lake Michigan is lower now than it’s been in over thirty years!” he just about shouted at me. “This isn’t some temporary bump in the road! Thirty years! It hasn’t been this low in THIRTY YEARS! Do you know what that means?”

“Yes,” I told him. “It means when your dad was in high school the water level was right were it is today.”

End of discussion.


  1. I was talking with a guy who lived in Door County, WI about lake levels. There is a cycle to them. It has been a few years since I had the conversation, but I remember 1995 was a good time to buy lake froint land. I think levels were going into a low cycle.

  2. I live near Lake Superior. What you said about the cycle of water levels is true. The info you gave did not include Lake Superior but, I think, would hold true for the entire Great Lakes region. Here is an Canadian site that has a graph that indicates the level of the lake back to 1918: The site states: ‘These fluctuations result from persistent low or high net basin supplies. They result in extremely low levels such as were recorded on some lakes in 1926, the mid-1930s and mid-1960s, or in extremely high levels such as in 1952, 1973 and 1985-86. More than a century of records in the Great Lakes basin indicate no regular, predictable cycle. The intervals between periods of high and low levels and the length of such periods can vary widely and erratically over a number of years, and only some of the lakes may be affected. The maximum recorded range of monthly water-levels, from extreme high to extreme low, have varied from 1.2 metres for Lake Superior to over 1.8 metres for the other lakes. The ranges of levels on Lakes Michigan-Huron, Erie and Ontario reflect not only the fluctuation in supplies from their own basins, but also the fluctuations of the inflow from upstream lakes.’