BLUE NOTES BY KEVIN SHAFER - JULY 2019

If you have been to the lakefront this summer, you may have asked, “Where did our beaches go?” This is the question being asked along the Lake Michigan shoreline throughout Wisconsin. Of course, the beaches are still there, but the water level of Lake Michigan is at record-breaking highs. The U.S. Army Corps of Engineers reported on July 5 that Lake Michigan’s water surface is three feet above Lake Michigan's long-term July average. The Lake is four inches higher than in May 2019 and 15 inches higher than this time in 2018. The Corps predicts these high levels to continue through August with another two-inch increase. The beaches are still there; they are just underwater. 

These high levels not only are affecting our recreational opportunities, but they are also posing problems for property owners along the shoreline, the Port of Milwaukee, marinas, and utilities, like the Milwaukee Metropolitan Sewerage District (MMSD). MMSD treats the wastewater from 1.1 million people and discharges this cleaner water into Lake Michigan. As part of the cleaning process, MMSD must pump the water into the Lake. With these high Lake levels, MMSD must use more energy to pump this water into the Lake, which increases routine operational costs.  

Another problem that MMSD faces due to high Lake levels is that Lake water also backs up the rivers closer to the Lake, which then can cause Lake water to flow backward into the Deep Tunnel system though some overflow points. Normally at these locations, a wall prevents flows from exiting the sewer system, unless we have a major rain event. These walls also prevent the Lake from backing up into the Deep Tunnel. At one location, the Lake levels have overtopped the wall and are pushing about 10 million gallons per day into the Deep Tunnel. During dry days, this volume is easily pumped out of the Deep Tunnel, treated, and discharged to the Lake. This imposes additional energy costs due to the extra pumping and exacerbates MMSD’s efforts to reduce overflows during heavy rains. MMSD is currently rectifying this problem, but there is a cost to fix this.

MMSD is also responsible for flood management in the region. Widening the river floodplain, removing concrete, and storing floodwaters are all mitigating approaches that MMSD employs. All our rivers drain into the Lake. High lake water levels cause higher water elevations in the downstream portions of the rivers, making the mitigating approaches less efficient and making it more likely that river flooding might occur.

Besides these larger impacts, MMSD also uses boats to sample and clean our waterways. With higher water levels, there is less room under bridges, causing our boats to have to wait for the bridges to be raised. This requires increased MMSD personnel work time, resulting in more costs. The next time you hear that Lake Michigan water levels are high, or you drive by and see a smaller beach, understand that there are many challenges these higher water levels create. With these challenges come additional costs and operational challenges, not only for MMSD but for everyone who lives in the Great Lakes. 
 

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