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Chicago takes a weather beating as lake levels rise

Chicago takes a weather beating as lake levels rise

High tide and 4-meter waves are eroding the shores of Lake Michigan in the city of Chicago.

The city's beaches and parks are disappearing under record water levels. Fall gales are sending 12-foot waves against Lake Shore Drive. Federal, state and city agencies are fighting to shield the coastline, and infrastructure repair is taxing a city that already has little money.

Like other major coastal cities, Chicago cannot afford to lose the fight. The Lake Michigan shoreline is the city's raison d'être, giving meaning to its title as the capital of the "Third Coast."

The water has chewed up millions of cubic meters of sand and earth on the north and south coasts of the city. Last week, the Chicago Department of Transportation and the Chicago Park District began an emergency shoreline protection project in Juneway Beach, about 10 miles north of downtown, with additional projects to follow in others. nearby beaches.

A city spokeswoman said the lake is about 1 meter higher than average for the month of November, and one centimeter below the record water mark in November.

"People who don't frequent the lake in the winter will see a very different shoreline than what they remembered at the end of last beach season," said Rob Moore, a Chicago-based climate adaptation expert at Natural Resources.

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On the south side near Jackson Park, where pedestrian and bike paths flood or simply disappear, the Army Corps of Engineers will begin building a massive rip barrier along the lakefront north of the future Barack Obama Presidential Library. The city will also extend 1,500 meters of “jersey barriers” along eight lakefront sections to mitigate wave action and flooding.

“Making sure the lakefront remains open and accessible to all Chicagoans is our top priority,” said Chicago Acting Transportation Commissioner Tom Carney when the first round of flood control projects was announced in September. .

Experts say the Lake Michigan assault on Chicago is being driven by climate change.

Near-record rainfall fell over the basin in 2018 and 2019, tilting the lake's balance between water inputs and evaporation, and raising lake levels to their highest level since 1986. Lake storms are more frequent and accumulate higher. power, posing additional risks for boaters, fishermen, and lakeside residents, businesses, and tourists.

"This is the type of year that may be more typical than not," said Don Wuebbles, professor of atmospheric sciences at the University of Illinois and lead author of a recent report examining the impacts of climate change on the Great Lakes. Wuebbles said the primary weather signal in the basin is one of greater instability, both in precipitation and lake levels, with dramatic rises and falls marked by extreme events.

Scientists project that high tide will last through spring, exacerbating Chicago's climate risk as the winter storm season intensifies.

And while flooding and coastal erosion will be the city's main challenges, inland flooding from winter gales is part of the city's history. In February 1987, a 70 mph north wind produced 20-foot waves that sent water across Lake Shore Drive toward nearby residential buildings.

If the challenges of Chicago's shoreline seem daunting, it's even worse on Lake Michigan's east shore, where homes teeter on the lake's high cliffs and water surrounds small towns along a severely rugged shoreline (Climatewire, August 22nd).

Conditions are less dangerous along the hardened shoreline of downtown Chicago, Moore said, where much of the shoreline is already encased in concrete and lined with piles and liners.

"But it's a real problem further south and north of the city, where you have a lot of private lakefront property," he said. "It's actually causing all kinds of problems, the most immediate of which is that there is a lot less space between the lake and people's houses."

While solutions to high lake levels are costly but feasible today, Chicago could face a much tougher future with regards to climate change over the next century. This is because the city is experiencing relative sinking, or falling, towards the lake due to what is called "isostatic rebound."

Scientists say the phenomenon, which is occurring very slowly, involves the upward lift of northern land masses that were compressed by glaciers during the last ice age. Since the glaciers receded, the northern Great Lakes basin has risen while the lower reaches of the basin, including Chicago, are declining relative to lake levels.

Scientists say that by the end of the century, average Lake Michigan levels will be about 10 centimeters higher at Chicago's Navy Pier than today, even without a further increase in precipitation.

Reprinted from Climatewire with permission from E&E Electronic News. E&E provides daily coverage of essential energy and environmental news at www.eenews.net.

Video: Caught in storm Lake Erie (October 2020).