Lake Michigan and Lake Huron lost almost 14 trillion gallons in past year; Why?
Posted on October 7, 2021
News Article from MLive. Read full news article HERE.
Most of the Great Lakes continue to have declining water levels from the record-high levels over the past few years. The water level decline of Lake Michigan and Lake Huron has been the most amazing.
Remember: Lake Michigan and Lake Huron share the same water level because the lakes are connected by free-flowing water through the Straits of Mackinac.
The water levels have been gradually increasing on Lake Michigan and Lake Huron since 2014. Lakes Michigan-Huron basically peaked last July in this recent water level rise. Now in the past year, Lake Michigan and Lake Huron are declining rapidly.
Lake Michigan and Lake Huron water levels (in red) looking back to September 2019. (Data from U.S. Army Corps of Engineers)
The U.S. Army Corps of Engineers has measured the decline in water levels on Lake Michigan and Lake Huron at 17 inches since July 2020.
One inch of water on Lake Michigan and Lake Huron represents 800 billion gallons of water. Getting out the big-number calculator shows a 17-inch decline is 13.6 trillion gallons of water on Lakes Michigan and Huron.
Why? Keith Kompoltowicz, hydrologist with the U.S. Army Corps of Engineers - Detroit, says it’s easy to explain. Dry weather is the cause of the fast lake level decline. The lack of precipitation this winter, spring and early summer was the cause. Kompoltowicz reminds us the biggest drivers of water levels on the Great Lakes are precipitation, evaporation and runoff.
The image below shows much of Michigan has had only 75 percent to 90 percent of normal rainfall. The drainage basin of Lake Michigan and Lake Huron is most of Lower Michigan, and parts of Wisconsin, Illinois, Indiana and Ontario.
Percentage of normal precipitation in the past year. (NOAA)
Kompoltowicz says the best way to see the dryness is to look at the U.S. Drought Monitor map from the height of this summer’s dryness.
Drought status on June 8, 2021
On June 8, most of Michigan was at least in moderate drought, and a large area was in severe drought.
Another oddity Kompoltowicz points out is the highest water level of this year. So far, Lake Michigan and Huron have been at their highest watermark in January 2021. If January remains the peak, it will mark only the third time since 1918 for a beginning-of-the-year high water level.
The water-level graph also shows the official water level forecast for the next six months. We certainly don’t have to worry about record high water levels anytime soon. Lake Michigan and Huron are forecast to continue to fall another 12 inches by January 2022. If we stay dry and the lakes fall to the lower end of the possibilities, the lakes will only be about six inches above the long-term average water level.
How quickly water levels can change on the Great Lakes.
