What Are Those Giant Structures Out In Lake Michigan?

There are six water cribs remaining in Chicago, but only two are still in use. So what might happen to them in the future?

Curious City Water Cribs Thumb
The Wilson Avenue water crib in 2016. David B. Gleason
Curious City Water Cribs Thumb
The Wilson Avenue water crib in 2016. David B. Gleason

What Are Those Giant Structures Out In Lake Michigan?

There are six water cribs remaining in Chicago, but only two are still in use. So what might happen to them in the future?

Earlier this summer, eighth grader Aiden Singleton was biking near Wilson Avenue Beach with his mom when he spotted a giant structure, almost like a house made of stone, out in Lake Michigan.

Aiden asked his mom, Danielle, what the structure was, but she wasn’t sure, either. So they turned to Curious City to find the answer.

Recently, Curious City met up with Aiden, Danielle and former executive director of the Metropolitan Water Reclamation District of Greater Chicago Dick Lanyon so that Aiden could learn more about these structures.

The short answer is they’re water cribs — and unfortunately there’s no way to explore them.

Water cribs are structures that help channel lake water into tunnels where it can then be carried into the city. Below the structures that you can see from the shore, “you have intake gates and screens that keep out things you don’t want, like logs and floating objects,” Lanyon said.

The cribs help protect the quality of the water and regulate the rate of intake. After the water is carried to the city, it’s then cleaned at a filtration plant and used for “drinking water, firefighting and all the water that comes out of the tap,” Lanyon explained.

Chicago started building these tap water sources in the 1860s under the guidance of an engineer named Ellis F. Chesbrough. It was a great engineering feat that allowed the city to use water further out from shore, which was a lot less polluted than the water along the shoreline. In the early days it was pumped straight from the lake into people’s homes but in 1945 the city built filtration plants to help treat the water.

Lanyon said originally there were nine water cribs but now there are only six left in the Chicago area, some of which have been inactive for years. Today only two are still in use because the city has two filtration plants and so only needs two cribs.

The Wilson Avenue water crib that Aiden spotted is no longer active, but you still can’t get anywhere near it. According to Lanyon, that’s partly because of terrorism concerns. After all, if you contaminate a city’s water supply, it can have devastating effects. So no one is allowed near Chicago’s water cribs, particularly the active ones.

When it comes to inactive water cribs, Lanyon said the security risk “is pretty minor, since they’re not in use.” But even an inactive water crib is “a piece of public infrastructure that the city owns. So they’re just protecting their property.”

As far as the inactive water cribs go, several ideas have been floated for how to repurpose them. Preservation Chicago has argued for them to be reused as restaurants or museums.

Questioner Aiden has an idea of his own: “I think maybe we could use them for building an airport out there, like a landing strip where then you would sail into the city.”

More about our question asker

Curious City Water Cribs Questioner Bio
Aiden and Danielle Singleton at Montrose Beach. Maggie Sivit / WBEZ

Aiden Singleton is a rising 9th grader who lives with his mom, Danielle, his father and his sister in Kankakee, Illinois. He’s looking forward to attending the Illinois Math and Science Academy in the fall.

For fun, Aiden enjoys composing music, learning to code and writing stories. In fact, he is currently finishing his first novel.

Danielle Singleton was born and raised in Chicago. In their spare time, she says she and her family love “riding our bikes, and my husband just got his pilot’s license so we fly over the lake all the time.”

So the next time they spot a water crib from the sky, they’ll know exactly what it is.

Monica Eng is a reporter currently living in Chicago. Follow her @monicaeng

Sophia Lo is Curious City’s multimedia intern. Follow her @sophiamaylo