July 2022 Water Level Update

 

Lake Michigan water levels have now peaked for the season, with 0 inches of change from June to July. Though Lake Michigan is now about 25 inches below the highest monthly water level recorded for June in 2020, the Lake is still about 9 inches above the long-term average water level. Water levels are expected to remain level until the seasonal decline in the fall.

Watch the USACE’s “On the Level” Youtube channel for monthly updates and information about the Great Lakes’ water levels and forecasts from Detroit District Hydraulics and Hydrology experts.


 

Water Levels on Lake Michigan-Huron

 

Here are five things to know about water levels on Lake Michigan for June to July 2022.

 

What are the current water levels on Lake Michigan?

The water level of Lake Michigan as of July 8, 2022, was at an elevation of 577.5 feet above sea level (from the International Great Lakes Datum). To put this level into perspective, here are some statistics for Lake Michigan relative to the period of water level records measured from 1918 to present (statistics from USACE’s Weekly Water Level Update and USACE’s Water Level Summary).

Compared to… Current Water Levels are…
One month ago 0 inches higher
One year ago 7 inches lower
Long-term June monthly average (1918 to 2021) 9 inches higher
Record June monthly mean (set in 2020) 25 inches lower

 

What is the outlook for future water levels?

Water levels on Lake Michigan have increased by about 0 inches from June to July. The USACE is projecting that water levels will remain level and predict no change through mid-August 2022 (see the water level forecast issued for June 2022 below). The leveling water levels are a seasonal occurrence. In the springtime, water levels gradually increase due to precipitation and runoff from snow melt. Additionally, evaporation decreases due to the increasing air temperatures while the water is cool causing water levels to peak around mid-summer. In an average year, water levels vary seasonally by about one foot from a peak in summer to a low in winter, though every year is different. You can read more about this as well as other myths about water level fluctuations in this blog.

Six-month water level forecast for Lake Michigan issued for this month. Source: U.S. Army Corps of Engineers. https://www.lre.usace.army.mil/Missions/Great-Lakes-Information/Great-Lakes-Water-Levels/Water-Level-Forecast/Monthly-Bulletin-of-Great-Lakes-Water-Levels/


 
What is behind Great Lakes water level fluctuations?

The story of Great Lakes water level changes is told by Net Basin Supply. Net Basin Supply (NBS) accounts for the water going into a lake in the form of precipitation and runoff minus water leaving a lake due to evaporation of water from the lake surface. In general, when Net Basin Supply is positive, more water enters the lake than leaves, causing a rise in lake levels. When Net Basin Supply is negative, more water leaves the lake than enters, causing a drop in lake levels. Click here for more detail.

 
What is making water levels peak?

Since record highs in 2020, the Great Lakes water levels have been trending downwards. This trend has continued through 2022 and water levels are lower than they were at the same time in 2021. The graph below visualizes the monthly difference from the long-term average NBS for the past five years. Red bars represent below average NBS, whereas blue bars represent above average NBS. Since the peak water level averages in 2020, the NBS has gradually decreased due to more water leaving through evaporation than entering the lakes through precipitation and runoff. Despite below-average NBS in April, May, and June, water levels remain above the long-term average for Lake Michigan.

This image shows NBS relative to long term average NBS for the past 5 years. https://www.lre.usace.army.mil/Missions/Great-Lakes-Information/Great-Lakes-Information-2/Basin-Conditions/#lkmih

 
Places you can find more relevant information:

  1. Our Coastal Hazards page for details about the impacts of high water levels, including erosion, flooding, and navigation issues.
  2. Our blog post Resources for Great Lakes Coastal Property Owners: Where do I start? has links to many resources to help
    • understand coastal hazards
    • weigh the risks coastal hazards pose to property
    • understand options for addressing these hazards
    • get started on implementing actions if necessary.
  3. The Great Lakes Water Budgets from the University of Michigan gives more information about what makes the lakes go up and down.
  4. The US Army Corps’ Great Lakes Information page has tons of details on view water level data, water level forecasts, basin conditions, outflows, etc.
  5. Our Resource of the Month on US Army Corps of Engineers Monthly Bulletin of Great Lakes Water Levels.