Lake Michigan seasonal water levels rise – the good, the bad and the ugly?
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EmailLake Michigan has rebounded from a record low in 2013. What are some of the issues now that the seasonal rise has begun?
Following the winter season, information from the coordinated gauges on Lakes Michigan (and Huron – as you know, they’re just one big hydrologic lake joined at the Straits of Mackinaw!) show the annual seasonal rise has begun. This rise typically begins in April as snow has melted from the Lake Superior and Michigan watershed areas and, combined with spring rains, and the waters are more fully entering the Great Lakes. A wonderful long-term data set exists for lake levels on Lake Michigan-Huron and typically a 12 inch seasonal rise from the winter low levels into summer highs occurs.
Fellow Michigan Sea Grant Extension Senior Educator Steve Stewart recently reviewed why Great Lakes water levels change over different periods of time in earlier Michigan State University Extension articles (What’s up [or not], with Great Lakes water levels/Part 1, What’s up [or not] with Great Lakes water levels/Part 2), and looked at 2015 predications basin-wide in Great Lakes water levels for the summer of 2015 - what’s up (or not)?.
The most recent six-month predictions by the U.S. Army Corps of Engineers show that Lake Michigan will probably stay in the area of 7 to 9 inches above the long-term average each month. Lake Michigan also has the highest variation of all the Great Lakes which is about 6-feet, 4-inches from the record monthly high (October, 1986, 582.35) to the record monthly low (2 years ago, January, 2013, 576.02). Many commercial shippers, recreational users, marinas and others describe a “sweet spot” of plus or minus 1 foot from the long-term average where access to the water, ability to load & carry cargo, and harbor mouth entrances is optimal.
If the lakes were to rise more than current models project and Lakes Michigan-Huron were to remain consistently over 12 inches above the long term average, educators at Michigan Sea Grant, NOAA, and other US/Canadian agencies may begin to change terminology and use the term “high” water and issues with coastal erosion could be paramount. However, even at today’s levels, localized places have significant erosion concerns.
In the tip of Leelanau County, near the Village of Northport, a prized coastal beach and access area is currently in danger due to erosion. Christmas Cove public access, a key Leelanau Township Park which was just recently expanded, is now at risk due to bluff erosion over the winter. The Township is currently trying to raise funds and install an emergency interlocking steel sheet pilings at a cost of about $100,000 to protect a parking lot and restroom facilities.
Extended winds and storms kick up the waves which eat away at shoreline; and often just a few storms can do 80 to 95 percent of annual yearly erosion. Cities, townships, villages and shoreline owners need to be aware of three scenarios:
- The Lucky Scenario: no major extended storms and lake levels stay within the sweet spot
- The Likely Scenario: some extended storms occur and lake levels may go up or down from the sweet spot. Some damage will occur.
- The Perfect Storm: an extended storm, just the right direction for a long-period of time will occur with extensive precipitation, high levels and have major and long-term impact.
It may be impossible to fully prepare for a perfect storm scenario, but we would do well to take a good look and keep a good watch for likely impacts in 2015 and into 2016.
The Great Lake coasts are wonderful yet dynamic places to visit, enjoy, live and recreate. Let’s enjoy the current “sweet spot” levels as we conduct business, bring our families to swim and recreate, and watch with awe and amazement the power of wave energy along our shorelines.
