June 4, 2010
New figures from Army Corp of Engineers show Lake Michigan/Huron/Georgian Bay water levels are on downward trend – well below the long-term average of other
Newest figures show water levels declining
The latest figures on
The newest monthly report just posted by the U.S. Army Corp of Engineers says water levels on Michigan-Huron in May were 14 inches below the long-term average levels. All other
More worrisome is that the Army Corp is projecting levels on Michigan-Huron could be below chart datum by the end of the year. Chart datum, also known as low water datum, is the reference point used on navigational charts to measure the depth of water throughout the lakes.
At the end of May, Michigan-Huron was about five inches above chart datum. The latest projections suggest the water could drop below chart datum in October.
You can see the Army Corp graphs here: USACE - Monthly Bulletin of Lake Levels for the Great Lakes - June 2010
Anyone who has looked at the water level graphs over the years notices a familiar pattern on how the levels change within a year – they start off low in the winter, go up steadily in the spring and then start dropping off gradually from July until the end of the year.
What’s unusual about this year’s graph for Michigan-Huron (and therefore, Georgian Bay) is that the normal down-up-down line has been replaced by almost a flat line. The typical rise in the spring hasn’t happened. The Army Corp is predicting a very slight rise in June and July, followed by the usual late-season decline.
Michigan-Huron levels are already about eight to 10 inches lower than they were a year ago.
