Updated at 1:30 p.m., June 6 with revised river crest forecast from the National Weather Service — The Mississippi River at St. Louis is expected to crest at 45.8 feet by Saturday afternoon.
A group of tourists posed for a selfie under the Gateway Arch midday Wednesday, while just a few feet away, murky floodwaters from the Mississippi crept up the riverfront steps.
Flooding has continued unabated for more than 80 days along rivers in the St. Louis area. Most major waterways, including the Mississippi, Missouri and Illinois rivers, are expected to crest Friday — with peak floodwaters in some regions rivaling records set in 1993.
As she observed the rising water along the banks of the Mississippi, Valley Park resident Cindy Derse couldn’t help but remember the last time she saw floodwaters this high.
“In ‘93, the water came up the Arch steps even higher,” said Derse, who visited the Arch Wednesday afternoon. “It was even more massive — really incredible, just the force of nature.”
The Mississippi River in St. Louis is expected to crest Saturday at 45.8 feet, about four feet short of the record set in 1993.
Hydrologists from the U.S. Geological Survey are measuring flows, or the volume of water, along the Mississippi River this week. The data they collect from river gauges and acoustic equipment can confirm or adjust the National Weather Service’s predictions about the height and timing of river crests, said Trent Legg, a USGS hydrological technician.
“I’ve measured here before,” Legg said, standing on a bank in Illinois near the Interstate-70 bridge. “It’s as high as I’ve [ever] been on it.”
It’s also possible that the forecast could change, depending on how the flood affects levees and other manmade structures along the river.
“If you have a levee break or some kind of restriction on the river, that can change those numbers,” Legg said.
Floodwaters have overtopped about 20 levees so far, according to the U.S. Army Corps of Engineers.
Others, including the Nutwood levee on the Illinois River near Hardin, have suffered serious breaches.
The “huge gaping hole in the levee” caused a substantial drop in the Illinois River near Valley City and Grafton late Tuesday, said Mark Fuchs, hydrologist with the National Weather Service.
“It does appear the [Illinois] river is beginning to rebound at all those points,” he warned.
For now, Fuchs said he hopes this week’s river crests will be highest of the season — but the possibility of severe summer flooding remains.
Snowmelt from the Rockies may put additional pressure on reservoirs along the Missouri, many of which are already nearing capacity.
The Missouri River Basin is also expected to receive “above average” rainfall this summer, said Fuchs.
“As history has shown us, we have seen years where our biggest rainfall events that caused the biggest flooding took place in June and July,” Fuchs said, citing the floods of 1993 and 2008. “We’ll have to keep an eye on this for a while.”
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