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Shoreline erosion is a ‘regional problem.’ Why is a regional solution for the North Shore so elusive?

As part of his job, George Russell frequently visited Sunrise Beach in Lake Bluff to monitor the receding shoreline. On one walk, he found some odd-looking lumber that had washed up onto the beach.

Russell, now retired from his post as Lake Bluff’s village engineer, knew the wooden planks with long nails were a sign that some homeowner’s bluff had failed — certainly as a result of waves eating away at the toe of the bluff, creating an unstable slope.

“The (planks) were clearly the remnants of someone’s staircase or deck system that was located on a bluff that just collapsed,” Russell said. “It was fresher-looking lumber.”

Many coastal experts and public officials throughout the North Shore say a ruined staircase or deck system may be just the beginning of the potential damage posed by a changing Lake Michigan shoreline.

While lake levels rise and fall in cycles, the lake’s sharp swing from a record low to record highs in just six years has some lakefront managers wondering if this represents a new normal.

“We are seeing within the past decade more intense storms and greater fluctuation in lake levels,” said David Bucaro, outreach manager for the U.S. Army Corps of Engineers. The past six years marked the greatest rate of change in a century of record-keeping, he said.

In A Changing North Shore, Pioneer Press has examined the consequences of rising Lake Michigan water levels and an eroding shoreline, and the choices facing suburban homeowners trying to protect prime real estate and public officials working to preserve treasured community assets.

It’s a problem that is very much top of mind for leaders and residents, but experts say long-term fixes remain elusive for the region.

One reason lakefront storm damage has been grabbing headlines lately is that existing breakwaters and onshore protections were not designed for the statistically improbable combination of lake levels and wave heights battering beaches and parks.

That’s why a storm surge in January over-topped breakwaters and revetments, twisted guardrails at a Lake Bluff beach and flooded structures constructed on dry land.

Shoreline protection designs are based on “hind-casting” and use past history on lake levels, wave heights, wind speed and direction as a proxy for what will happen in the future, Bucaro said.

“That works fine if the future is going to mimic the past,” Bucaro said. “But if we think the future is going to be more intense, more variable or more dynamic, then that is not the right way to go. The problem is that, at this point, we don’t have a better method.”

Protections are not designed for extreme conditions because as lake levels decline, an over-engineered breakwater or barrier detracts from the natural beauty of the lakefront, and waves bouncing off the structure can accelerate erosion of properties nearby, area engineers say.

As of June, Lake Michigan-Huron’s water level was 582.16 feet above sea level, which is how the Great Lakes water levels are calculated. The previous June high water record was 581.79 feet, set in 1986, according to the U.S. Army Corps. July’s average level was 582.19 feet, according to the data. Provisional data for August shows the lake levels largely unchanged so far this month.

“We are at a point now where any sort of storm or wave action, any sort of wind, can cause some significant and very impactful things along the shoreline,” said Keith Kompoltowicz, chief hydrologist for the U.S. Army Corps of Engineers’ Detroit District.

The rapid rate of erosion has forced area park districts and municipalities along the North Shore to grapple with whether to further buttress shorelines, add offshore breakwaters or take on bluff stabilization projects to halt bluff slides and the loss of prized beachfront.

Conversely, the cost of doing nothing — or waiting too long — could prove irreversible for North Shore communities and the region, according to coastal engineers. To complicate matters, each community has a unique geography that requires independent analysis and site-specific solutions, as well as different constraints on how to pay for it all.

“Each of these communities works individually, which totally makes sense,” said Diane Tecic, coastal management program director for the Illinois Department of Natural Resources. “This is their land. They have to do what they have to do to protect that land. The problem is that Lake Michigan is a large system and it is a regional problem.”

‘This is a longstanding issue’

In the battle against erosion, sandy beaches provide a crucial line of defense. But along the North Shore, less sand is arriving naturally in the wind-driven currents of Lake Michigan that flow from north to south.

Land-use changes along the Wisconsin shoreline are one reason less sand has reached North Shore beaches, Tecic said. The sand transport known as the “littoral drift” also is interrupted by structures at Waukegan Harbor and the Great Lakes Naval Station that date to the late 1800s and early 1900s, respectively, researchers and engineers have noted.

“This is a longstanding issue: How to manage our shoreline when we in Illinois have such an altered shoreline and so many different breakwaters?” Tecic said.

Once the sand lining the nearshore lake bed is gone, waves dig into the cohesive clay that was deposited by glaciers, creating deeper water at the shoreline that bring higher and more damaging waves onto the shore, according to coastal engineers.

“If you lose the clay, the beach gets pushed to the west and gets smaller because the underlying soil is gone,” said William Weaver, vice president of AECOM, a geotechnical and coastal engineering firm that recently completed erosion studies for Lake Forest and the Lake Bluff Park District. “If the waves reach the bluffs behind where the beach used to be, the bluffs start to erode very quickly.”

The loss of clay already has taken a toll on Lloyd Beach in Winnetka, a non-swimming beach used for boating and other forms of recreation.

Sand deposits are thin near the shore and total less than one foot in some locations, according to consultant Jon Shabica. The Park District applied to the Illinois Department of Natural Resources last fall for permission to construct three stone breakwaters and a seawall at the beach.

The beach is closed to visitors with the south end gone. According to the Winnetka Park District, just a small area of beach exists on the north end, but it is often overtaken by waves.

Lloyd Beach’s vulnerability to erosion and the ramifications were pointed out nearly four decades ago by the U.S. Army Corps of Engineers.

In a 1982 draft reconnaissance report, the Corps predicted the beach, then 60 feet wide, would continue to recede at about three feet a year and could be gone in two decades, depending on lake levels and storm intensity.

“Eventually, all recreational activities may no longer be possible at the park,” the report stated.

But while erosion control received lots of attention when lake levels rose to record highs in the 1980s, the sense of urgency faded during the prolonged period of low water that followed.

“We went about 12 years with below-average lake levels and everyone thought that was the new norm,” Bucaro said. “There was not a whole lot of planning that was being done.”

‘You need to truly understand the problem’

After erosion at Highland Park’s Rosewood Beach claimed large quantities of sand, threatening the beach’s boardwalk and infrastructures, park district officials scrambled to add thousands of tons of protective sand in October ahead of storms that would have almost certainly caused structural damage.

In Lake Bluff, a task force was looking at how to phase in $5 million in erosion remedies to spread out the cost, when a storm surge in January flooded a guardhouse, destabilized a revetment and claimed beach sand down to the clay in one cove.

For Tecic, the state’s director of coastal management, it was a huge storm event on Halloween five years ago that underscored the need for a regional strategy.

The state had just spent about $1 million to add quarry sand to Illinois Beach State Park near Zion, only to see the storm wash it away. It was clear to Tecic that spending a million dollars annually to replace sand at the state park was not a sustainable strategy, she said.

At the same time, an overflow of sand was clogging Waukegan Harbor on the north side of a pier, leading the U.S. Army Corps of Engineers to dredge the harbor to allow passage of commercial vessels. South of the pier, beaches were starved of a protective sand covering.

Working with the Alliance for the Great Lakes, IDNR’s coastal management program brought together public land owners from Evanston to Waukegan and commercial users of Waukegan Harbor in 2015 to brainstorm solutions.

As a result of the collaboration, four participating communities volunteered to receive clean sand dredged from Waukegan Harbor as part of a federal pilot program testing ways to make beneficial use of dredged sand and sediment. The joint application from Evanston, Glencoe, Lake Bluff and North Chicago was one of 10 selected nationally and the only one on the Great Lakes.

A study released by the Army Corps earlier this month details the plan to dredge 60,000 cubic yards of sand from the harbor next summer, place it onto a barge and then transport it to the area beaches.

Tecic is also hopeful that research into near-shore hydrodynamics will yield data useful to local communities as they work to identify solutions to erosion and, perhaps, make a case to their federal legislators for funding.

“It is one thing to say, ‘We have lost beach.’ But it is another thing to really understand how fast it is moving,” she said. “There are some places that lose beach and then they get more back.”

Tecic said data also is needed to assess the effect of storms, wave heights and wind directions and how structures affect the natural processes.

“If you want to come up with a sustainable solution, you need to truly understand the problem, so you don’t come up with solutions or strategies that are going to exacerbate the problem,” she said.

Bucaro said the Army Corps’ coastal hydrology laboratory in Vicksburg, Va., is investigating ways to incorporate future conditions into coastal designs for the Great Lakes rather than rely solely on historic experience.

“By basing the future on what has happened in the past, we as engineers may be underestimating the forces these structures could be subjected to in the future,” Bucaro acknowledged.

As stewards of the Lake Michigan shoreline, public land holders along the North Shore feel a weight of responsibility for protecting their towns’ treasured assets. But the extreme storms of late have been a humbling reminder that the forces of Lake Michigan are beyond their control.

In Highland Park, boaters who use a launch at Park Avenue Beach frequently remind park district officials of the consequences of allowing a disintegrating barge-breakwater to fail completely. That would leave a quiet beach cove unprotected from lake turbulence and signify an end to recreational boating at the location, many boaters contend.

“We are sure this is not the legacy that the park board wishes to leave for future generations,” said Laura Knapp, the current commodore of the North Shore Yacht Club, earlier this year. “If the park district makes the investment now, the community will have use of this asset for years and years to come.”

By making that investment, she added: “Today’s citizens, their children and their children’s children can continue to take pleasure in this really beautiful spot.”

gbookwalter@chicagotribune.com

kcullotta@chicagotribune.com

This is the third of a three-part series on how erosion is impacting the North Shore.

Part 1: As Lake Michigan waters rise, erosion poses an existential threat to North Shore towns and homeowners

Part 2: A lot of money for ‘a bunch of rocks’: The costs of combating erosion are forcing North Shore communities into hard choices