Lake Levels

February 10th, 2013 at 2:00 am by under Bill's Blog, Weather

   The first image is the MODIS Great Lakes satellite image from Weds. (Feb. 6).  You can see ice in Green Bay, some ice east of Chicago and there is ice up toward the Mac Bridge.  There’s a fair amount of ice on Saginaw Bay and on Lake Erie, which despite being the Great Lake that is farthest south, often has the highest percentage of surface ice cover of any of the Great Lakes because it’s the shallowest of the Great Lakes.  The second image from NOAA (here’s another image) shows Great Lakes ice as we enter the 2nd week of February.   You probably heard that Lake Michigan has reached it’s lowest water level since records began in 1918.  The article cited “USACE (Army Corps of Engineers) says below-average snowfall last winter, combined with a hot dry summer, contributed to more evaporation and the record low levels”.  Let’s explore that statement a little.  Lake Michigan is down 15″ in the past year.  Season snowfall last year in G.R. was 51.2″, below the current average of 74″ (that average went UP 2″ when the new 30-year averages were implemented (1981-2010)…the decade of the 2000s was the snowiest decade EVER in G.R.).  First, with a snow/water equivalent of 15 to 1, that would only amount for a 2″ drop (assuming that the watershed had similar low snowfall totals) on the lake, not 15″.  However, we shouldn’t look at snowfall.  A better measure would be total precipitation (rain and snow).  If we had below average snowfall, but above average rainfall – then Lake Michigan’s water level would probably go UP instead of down and you couldn’t blame a substantial loss of water like that on a lack of snowfall…well…read on.

Precipitation for G.R. was ABOVE AVERAGE in G.R. in December 2011 AND in January, February and March of 2012.   Yeah, it was dry during the summer, but on those really hot days in July, look at how light the wind was.  With calm or very light winds, a cooler layer of air with higher relative humidity would have been sitting over the lake water.  Also, precipitation for Grand Rapids over the last 2 years has been ABOVE AVERAGE.   Precipitation in 2012 for G.R. was 33.85″.  That was 4.42″ below the 1981-2010 average of 38.85″ (or 88.45% of average).  Precipitation in 2011 for G.R. was 45.09″ or 6.82″ ABOVE average (or 116% of average).  That average precipitation for G.R. has been increasing.  The average we used for G.R. from the 1941-1970 data was 32.39″.  Part of the increase is changes in land use.  We have now planted the Midwest in corn and soybeans and yields have increased as we now plant individual plants very close together.  I’ve talked before about transpiring corn and soybeans and how much water they can add to the air.  If you’re old enough to remember corn fields back in the 1950s you’ll know that they plant corn plants much closer to each other now than they did back then.  Look at the graph on this page and you can see the increase in yield per acre.  Even in a drought year like last year, the average yield per acre is higher than it was for any year back in the 1980s.   Side note, the Texas State Climatologist, Dr. John Nielsen-Gammon states in this article that “There is no evidence that climate change contributed to the lack of rainfall, because rainfall has risen over the past century…”   If you look at the 2012 Climate Summary for Muskegon, the average wind speed was 8.9 mph and the average humidity was 67%.  This chart from the National Climate Data Center gives an average annual relative humidity for Muskegon of 64% (lower than last year).  Now, Muskegon is just one location.  I don’t have time to do a detailed study on the Lake Michigan/Lake Huron Watershed.  About 30% of the equation for the later level of Lake Michigan/Huron (for lake-level purposes these 2 lakes are really one big lake, connected at the Mac. Bridge) is water that comes down the St. Mary’s River from Lake Superior.  Lake Superior’s water level has not dropped like Lake Michigan/Huron, as it’s unchanged from one year ago (compared to the 15-inch drop in Lake Michigan/Huron).  You may also see in related articles that Lake Erie has also dropped quite a bit (down 20″ in the past year).  That’s true, but Lake Erie fluctuates to a much greater degree than Lakes Michigan, Huron or Superior.  Lake Erie is only 4″ below average water level, which means with a 20″ drop, it was actually 16″ above average one year ago.

So, let’s look elsewhere.  Read this article from the Milwaukee Journal.  The first sentence says:  “Pressure is mounting on the U.S. and Canadian governments to explore ways to restore water levels on Lakes Michigan and Huron that have been lowered nearly two feet due to historic dredging on the St. Clair River.”   Again that’s “…due to historic dredging on the St. Clair River.”  The article also says:  “the federal government has long acknowledged that this human meddling in the riverbed has led to a permanent drop of about 16 inches from Michigan and Huron’s long-term average.”   and “…a Canadian conservation group created by property owners from northern Lake Huron’s Georgian Bay hired its own engineering firm to conduct a study of what was going on in the St. Clair River back in 2004. That study said the water lost from the lakes by expanding the river channel was actually much greater than 16 inches – and getting worse.” Thanks to Dan Egan for the work he did on this article.  He went beyond just retyping a press release.   While some are blaming lower snowfall for a single winter or the general “climate change” for the 15″ drop in a year of Lake Michigan’s water level, maybe that’s only part of the answer, or not the answer at all.

While, I’m at it…one more point.  Look at this climate page from the GRR NWS.  This is a comparison of the 1971-2000 30-year climate averages for Grand Rapids and the current 1981-2010 climate averages.  Look at snowfall.  The average snowfall for Grand Rapids went up!  By eliminating the 1970s and adding the 2000s, the average snowfall increased from 72.2″ to 74.9″.  People my age remember the big blizzard of 1978 and the cold winters from 1976 to 1979 when we had few thaws and the snow hung around longer.  However, those winters were not average.  The winter of 1976-77 was the coldest winter in G.R. in the last 100 years.  The following winter we had the big Blizzard of ’78, followed by the coldest February and the 5th coldest March ever…and in 1979, Lake Michigan pretty much froze over.  That was an unusual trio of cold winters, not average winters.   While we were below average for snowfall last winter, that’s hardly been the trend.  I wish I had more time to study this issue myself.  I grew up about two miles from Lake Michigan and I remember the low water of the mid 1960s and the high water of 1986-1987.  The water level of a lake like Lake Michigan is a complicated conglomerate of many different variables.  The below average snowfall of last winter does not explain a 15-inch drop in the water level of Lake Michigan.

11 Responses to “Lake Levels”

  1. Jack says:

    Hee ,Hee, FIRST, And a CUE for THIS THREAD…… Listening To : Reddog / Down, Down, Down – YouTube

    ► 4:43► 4:43
    Great Tune…Enjoy….BILL !!!! ;-)

  2. Dan says:

    So, while the snow pack can be a decent contributor to Lake Michigan’s water level, there are clearly other factors that contribute to the deficit. fixxxer: Please return the water that you have been siphoning off! Just kidding, fixxxer!
    What can a decent snow pack and a wet Spring contribute in a few months to put a dent in the deficit? I’m talking about averages. Can be very difficult to nail down, I’m sure there is quite the variance year to year.
    I continue to be amazed at how much Lake Michigan affects our weather here!!
    Thanks Bill for the interesting information!

    1. ResourcefulNana says:

      Wow, Lake St. Clair must be a HUGE hole in the ground now that the dredging is complete. Are there any figures to help me understand? For example, if we removed one inch of water from the entire surface area of Lake Michigan/Huron, how many gallons would that be? and Lake St. Clair is believed to be “holding” 14 or so inches of the two combined Great Lakes? I must agree that there has to be several contributing factors. Has anyone explored the flow of the surface waters (rivers and streams) that feed L. Mich and Huron? I live in the St. Joseph River watershed in St. Joseph County==the most irrigated county east of the Mississippi. Part of the watershed had numerous flood warnings last spring (Portage River south of Vicksburg), yet by summer, we barely had enough water to float a kayak in places. The flow was extremely slow and low. Farmers are pulling water from both surface and ground water sources. And even when I was surrounded by irrigation systems last summer in the dry heat, I could feel the moisture being pulled from my skin in a way I’m not accustomed to. My hunch is the air was pulling moisture from surface water and plants at a similar “higher than usual” rate. And, since warm air holds more water than cold air, it was carried away and dumped somewhere else. It’s fascinating to see that for the most part, Michigan is the only state that drains into the Great Lakes and so the flow of our rivers into the lakes must have some impact on the lake levels. It might not matter much how much precipitation falls, it might matter more how much of that precipitation flows from the rivers into the Great Lakes.

      1. Bill Steffen says:

        Each inch of water on Lake Michigan represents 390 billion gallons. Water flows from Lake Huron through the St. Clair River and into Lake St. Clair then out of Lake St. Clair down the Detroit River to Lake Erie. I don’t know how accurately you can measure the volume of water going down the St. Clair or Detroit Rivers. The City of Chicago is allowed to drain 3,200 feet per second of water from Lake Michigan. About half of this is for the city water supply and the other half to drain down the Chicago River (which takes water southwest eventually to the Mississippi River.

  3. Navyvet1977 says:

    Thank you Bill for all your info on this issue. I remember in’77 I was in great lakes Ill. going through my basic training. That was the coldest winter I remember. Especially the snow storm. Windchills were way below zero. And you mentioned the high water levels of ’86-’87. I believe it was ’86 when we had all that heavy rain. And I believe that was also the year we had a scare about the possibility of the Hardy Dam breaking. My grandparents had a cottage on the white river in white cloud and the flooding waters of the river washed away a one lane bridge upstream.

  4. kapper7780 says:

    so many people so quick to think they have the answer without looking at all of the possibilities. I remember in the high water days hearing the experts saying that it would take years and years for the water levels to get back to anything near normal and that hundreds of homes were going to be lost and towns go under water. and now people have bigger beaches than ever. so if the dredging is the cause then maybe is the new average and its time to move the docks plant some new dune grass and wait for the dredging to fill in.Then in twenty years when the water comes back up start the process all over again.

  5. Brad (Lawrence) says:

    Good reading Bill. Lots of interesting stuff you posted. I have been reading many articles in the past few weeks about this. One of the news articles I came across actually states the ACOE was saying that a lack of normal snowfall in the last decade was a contributing factor. When I saw this, I was stunned. I remeber you saying that we have had one of the snowiest decades on record from like 2001 to 2011. I have been searching for the article, and If I find it, I will post a link.

  6. Brad says:

    Regarding the last post, it would be cool to see a “mean duration of snowpack” stat. It should correlate with temperatures, but we could probably answer whether our more recent snowpacks are of shorter duration relative to those in the “past.” We could look at average snow depth, etc. too.

  7. BJ says:

    Thank you Bill for the excellent post. This was so interesting to read. I was looking at Lake Michigan-Huron water levels since 1918 and the years 1926 and 1964-65 also had pretty low levels. I wonder what conditions were present in those years for the levels to drop so low?
    Thank you again for the information. I like looking at the satellite photos of the Great Lakes. We are lucky to live in Michigan.

    1. DanielG says:

      Excellent point BJ, you beat me to the punch. I also remember 1964/65 and Grand Haven having a very large beach and a long walk to the water for an 11 year old. Also remember the 80′s at Kirk Park in Ottawa county when there for all practicle purposes NO beach at the south end, the water was right up to the dune face!
      What was the weather/water interface and its correlation to the Great Lakes water levels back then? Someone with WAY more expertise may be able to come up with an answer…

  8. Erik says:

    How many gallons of water does it take to make lake Michigan rise one inch?
    According to Darryl Enriquez of the Milwaukee Journal Sentinal, 1 inch of water depth in Lake Michigan accounts for 390 BILLION gallons of water.

    He also reports that “The loss of an inch of water in the other lakes translates in billion of gallons as follows: Lake Superior, 550; Lake Huron, 400; Lake Erie, 170; and Lake Ontario, 130″

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