Shoreline erosion along Lake Michigan in the northern suburbs has been an issue for decades, but new research indicates the situation could be getting worse.

Eight decades’ worth of aerial and satellite imagery taken over Illinois’ northern lakefront reveals that some stretches of shoreline are retreating at unprecedented rates, including Illinois Beach State Park, where acres of sprawling dunes and wetlands are now underwater.

The northern stretch of the park’s 61/2-mile long beach is arguably the hardest hit piece of coastline in the state. From 1939 to 2014, the shoreline has retreated more than 600 feet, the span of two football fields — an average of 8 feet per year, according to state geologist Ethan Theuerkauf.

In a little more than two years, from 2014 to 2016, erosion has accelerated dramatically, with the loss of 184 feet of beach. That’s an average of 84 feet a year.

Change in sand at Illinois Beach State Park

Erosion and sand gain at Illinois Beach State Park near the Wisconsin border accelerated in the last two years as compared with the previous 77 years. Here are readings for four locations along the shoreline of the park.

Location	Sand change rates		Total sand change
Feeder Beach		-8 feet/year -38 feet/year	-631 feet -84 feet
17th St.		-8 feet/year -84 feet/year	-619 feet -184 feet
21st St.		-6 feet/year -43 feet/year	-462 feet -95 feet
Dead River		2 feet/year 20 feet/year	168 feet 45 feet

Source: Illinois State Geological Survey

Farther south, in Waukegan, there’s been an emergence of dune land over time. Since 1939, the breakwater featured on the city’s seal has trapped enough sand to push the suburb’s waterfront 860 feet into the lake, growing at a rate of 11 feet each year, Theuerkauf said.

The ebbing beachfront at the state park in Zion and the emerging lakeshore in Waukegan exemplify the paradoxical changes occurring along the Illinois shoreline due, in part, to lakeside development beginning about two centuries ago.

Before human interference, sand naturally drifted along the shoreline unobstructed from Wisconsin to the present-day Indiana Dunes.

Illinois Beach State Park

As piers and harbors were built, sand became trapped in some places, depriving beaches farther south. When sand-starved beaches began to wither, communities began to install shore protections to keep their sand, which further impeded sand flow.

“What we found out is this is a much more complicated dynamic than we ever thought,” said David Bucaro, of the Army Corps of Engineers’ Chicago district. “Originally, the thought was, when you have erosion, you have to protect that shoreline.

“But when you do that, you actually cut off sand supply. When you protect one shoreline, it will have impacts elsewhere and it ends up unraveling. That’s what we have. We have so much development, we no longer have a naturally functioning system.”

As shore protections were installed in southern Wisconsin to protect against bluff erosion, less sand has drifted south of the state line to nourish Illinois Beach State Park. At the same time, the park’s mostly natural waterfront continues to hemorrhage about 188,000 cubic yards of sand each year, according to a draft of a study by the Army Corps of Engineers.

Waukegan’s North Beach Park collects 43,000 cubic yards of sand a year thanks to the city’s breakwater. But as North Beach Park grows, the municipal beach that the breakwater was meant to protect has shrunk considerably. The city’s longstanding commercial shipping industry has been crippled because sand perennially clogs its harbor.

The impediment to sand flow means North Shore suburbs south of Waukegan get about 78 percent less sand than they did prior to significant lakeshore development, according to a draft of an Army Corps of Engineers report.

Though the most noticeable concern is lost sand on land, an even more disturbing trend — and a chief reason why erosion is getting worse — lies underwater.

Waukegan

Over the decades, the man-made interruption of the southward sweep of sand has left some sections of the lake bottom bare. Violent waves during storms are digging the uncovered clay lake bed deeper, allowing for larger, more powerful waves.

The irreversible process, known as “downcutting,” is what led scientists in the 1990s to suggest that erosion was rapidly accelerating.

“As it goes through time it gets worse and worse,” Theuerkauf said. “It doesn’t bounce back.”

Researchers believe climate change, which is blamed for more powerful weather events, could play a factor. Only this year has the state begun monitoring beach erosion before and after powerful storms. But, in looking back at past events, the coincidence between heavy sand loss and strong weather events is evident.

Looking at the northern part of Illinois Beach State Park, preliminary findings indicate it lost 27 to 62 feet of shoreline between 2010 and 2012, a period coinciding with fall storms in 2010 (dubbed the “Chi-Clone”) and 2011. About 27 feet of erosion is likely the result of Hurricane Sandy, the huge 2012 storm whose effects reached into the Midwest. The Halloween 2014 storm that brought 20-feet waves also contributed to beach erosion.

Though the data aren’t a perfect snapshot of weather-related erosion, it shows that “storms clearly drove erosion in the recent past, and you can hypothesize that if we had more frequent and intense storms in the future that enhanced erosion would ensue,” Theuerkauf said.

In recent years, the threat has become enhanced as lake levels surged from record lows in 2013 to about 1 foot above average starting in 2015. The higher level not only swallowed up more beach, but also created the potential for taller waves.

In response to a sand shortage, many shoreline communities resorted to the expensive practice of purchasing sand from inland deposits. For a number of years since 1998, the state tried to alleviate the erosion at Illinois Beach State Park by placing sand dredged from Waukegan Harbor.

A year and a half ago, a collective of North Shore communities and environmental agencies was formed to address erosion issues. The Illinois Department of Natural Resources hopes one of the group’s first major actions will be cutting a deal to provide dredged sand to beaches in other communities, said Diane Tecic, program director of the Illinois Department of Natural Resources’ Coastal Management Program.

With a dearth of sand in some places and an abundance in others, a fix may seem simple. But permitting and regulatory roadblocks involving sand movement make an answer more complicated. Chief among those hurdles is the Clean Water Act, given that contaminants like asbestos can be found in some lakeside sand deposits.

Although members of the Illinois EPA are working with the North Shore group, recycling sand is a “Band-Aid” approach that needs to dovetail into a more nuanced, long-term solution, Tecic said.

“Just moving sand around year to year is a money drain,” Tecic said. “There may be some sand movement forever, but not this amount. Maybe there’s something we can do to keep sand in place for a longer period of time, but those kinds of things require that we know more about the dynamics.”

It’s an ironic turn of events considering that for ages, sand has been considered an immeasurable resource, only recognized by beachgoers for its propensity to get caught in shoes or sizzle bare feet on hot, summer days.

Earlier this year, Illinois State Geological Survey surveyed Lake Michigan’s shoreline from Kenosha to the Illinois-Indiana state line with an electromagnetic array in an effort to give researchers the most complete picture to date on how much sand is in the lake and where it’s located. The project could shed light on whether there are large off-shore sand deposits.

Experts like Charles Shabica, a retired earth sciences professor at Northeastern Illinois University, said there very well may be a significant amount of sand to be reclaimed in Lake Michigan.

“Once you’re in water 18 feet or deeper, it’s hard for waves to move sand back to shore,” Shabica says. “Sand stays there and moves off-shore, because the lake is like a bowl, and sand has the tendency to want to roll downhill.”

However, even if that’s the case, Shabica said a venture of that caliber would likely be too expensive.

In the absence of spending constraints, coastal engineers and researchers would like to replicate sand-management efforts in Galveston, Texas, where the coastline was devastated in the aftermath of Hurricane Ike in 2008. After voluminous reports on the beach, officials poured tens of millions of dollars into strategic sand placement.

While there’s still much to be done before any modifications would be made to Illinois’ lakefront, the North Shore sand think tank, which has reached out to partners across state lines, hopes to start the conversation on a regional approach to maintain beaches.

“What I’m hoping for our effort is that we can find some novel strategies,” Tecic said. “We’ve got a lot more technology now and hopefully we can come up with some other ideas that are going to be workable or less costly than armoring everything.”

Sources: IL Dept. of Natural Resources, US Army Corps of Engineers, EPA

tbriscoe@chicagotribune.com

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