Rainfall Means Higher Water Levels

Rainfall in Chicago and over the Midwest has been far above normal for more than a year, and its good news for Lake Michigan.

“The evidence is showing the water levels are higher than last year,” said Kurt Hettinger of the Shedd Aquarium.

Hettiger explains that as the water level rises, there are immediate benefits for fish habitat in Lake Michigan.

“Its good, affects shallow water, better breeding grounds,” said Hettiger.

While the replenishment can have a huge impact on the overall health of the lake over time, the lake level going up doesn't secure the future of the lake indefinitely.

“It’s a cyclical thing. It's been shown every 15 to 20 years lake levels fall and rise,” said Hettiger.

Just two years ago, lake levels dropped to within three inches of the record low set in 1964. The reason for the recent rise can be found in climate data: two snowy years back to back in Chicago and an extremely wet spring. It’s important to remember that rain that falls over the Chicago area drains mostly to the Mississippi River but not into Lake Michigan. But Chicago’s wet weather comes from the larger regional pattern which does affects the lakes' drainage basin. And, it's that wet weather pattern that has replenished Lake Michigan.

“They are back up, but they are not at normal,” said Hettiger.

The lake is still about eight inches below the long-term average. With the forecast for a wet spring and summer in the upper Midwest along with snow melt, its possible levels could rise of up to another four inches before autumn. But even with rising lake levels, urban runoff and water usage still impact water quality in Lake Michigan and Hettiger warns that conservation should continue.

“Even though they are risings, we were at record lows. Realize the lakes are vulnerable,” said Hettiger.