Chicago is built on a swamp, which means that its proximity to Lake Michigan has always required engineers to devise ingenious solutions to the problems that proximity causes.
Now that climate change is causing the lake’s water level to oscillate wildly at historically unprecedented rates, those methods are suddenly becoming unsound:
THAT AFTERNOON TYRONE VALLEY, lockmaster at Chicago Harbor, got a call. There was big trouble brewing in the river.
Mr. Valley, 56 years old, had just worked an overnight shift at the lock, and he was looking forward to having the week off. But his crew needed him back because the rains that had been pounding the city for three days were threatening Chicago in a fashion no one had experienced.
He hopped into his red Ford F-150 and started the hourlong drive back from his home in Joliet (yes, named after that Joliet). Along the way, his crew called him with alarming updates: Water was rising menacingly fast against the riverbanks in the heart of Chicago. “There were a few curse words exchanged on that drive,” Mr. Valley recalled.
Tyrone Valley, lockmaster.
River managers have a trigger point for opening the lock gates — reversing the river’s flow into Lake Michigan — in order to protect downtown Chicago from disaster. That trigger is typically 3.5 feet above Chicago’s official ground level, which, in the universe of river managers, is considered 0 feet.
Normally the river, as measured on giant white rulers tiled on the lock’s walls, ranges between 2 and 3 feet below ground level. That’s about where it had been when Mr. Valley had headed home that morning.
But there was a problem.
Three days earlier, a relentless storm had dropped a record 24-hour rainfall for that date. The tunnels and reservoirs had done their job helping to contain the deluge. But then, a second storm hit while the reservoirs were still holding water from the first storm.
That meant the storm water and sewage had to be released straight to the river. And it was too much for the river to handle.
By 5:23 p.m. the river level hit +3.5 feet, the point under normal conditions to open the lock gates and reverse the river into Lake Michigan. Messy, yes. But not as messy as letting sewage-laced water pour into downtown. However, this time conditions weren’t normal.
Lake Michigan’s level at that moment was at a record high for May — well above the river. So opening the lock wasn’t an option, because that would have sent lake water pouring into the river, flooding the city.
At 6:16 p.m. the river hit +3.8 feet. Then, less than 10 minutes later, it hit +4 feet, a number “we thought we’d never see,” said James Duncker, a hydrologist with the United States Geological Survey.
At that moment, Mr. Valley was standing along the lock wall, helpless. The sewage-laced muck smelled “like rotten eggs,” he said.
Then, at 6:54 p.m. the river surged to +4.6 feet, putting it about five inches above the level of the lake. Finally, Mr. Valley had options again.
Testing the lock at Chicago Harbor.
He gave the order, and his crew opened the immense steel lock gates. A whoosh of water carrying all manner of waste — trees, chunks of dock, litter, toilet flushes — blasted into Lake Michigan.
In mere minutes, the suddenly reversed river, roaring like a freight train, dropped below lake level. This was a new problem; If the gates stayed open, lake water would slosh back into the river, further flooding the city.
There was nothing in the playbook for this scenario. Mr. Valley and the lock operators had to wing it, pinching the gates closed to let the river again rise above the lake, then swinging them open again to let the swollen river drain into the lake.
Again and again, the crew repeated these steps. They were, almost literally, bailing out a flooding downtown Chicago by flapping the steel gates.
“We just did it on the fly,” Mr. Valley said.
Still, it was not enough. The river kept climbing, eventually peaking at +5.12 feet a little after 7 p.m.
The resulting floodwaters not only submerged the bustling Lower Wacker Drive, one of the city’s main arteries, but also knocked out the electrical power at the nearby Willis Tower (formerly the Sears Tower) all the way up to the aircraft warning lights atop its tusk-like antennas. A city hotline fielded more than 1,500 distress calls from residents whose basements were flooded.
This is snippet from an amazing piece of in-depth reporting and analysis of just one of the uncountable crises that climate change is bequeathing on us, and even more so on our children, and their children, and so on and on.
It’s very much worth reading in full.