More than seven inches of rain — with sporadic heavy downpours thrown into the mix — within a 72-hour stretch from midnight on May 15 until late on May 17 resulted in widespread street and basement flooding in Riverside, Brookfield and North Riverside.
The Des Plaines River in Riverside crested around noon May 18 at 10 feet, but with more rain in the forecast for late Monday into Tuesday, it was not clear at press time whether that would be the high-water mark for this event.
As it was, the 10-foot crest was the second highest ever recorded in Riverside, trailing only the crest recorded in 2013, when the Des Plaines River hit 11.28 feet.
“I don’t think this one was as bad as that one,” said one longtime resident of Groveland Avenue, who was out surveying the river level opposite his home on Monday morning.
That storm resulted in about seven feet of water in the man’s basement, he said. This time, it was about four feet. Neither flood however, compared to 1987, he said, when the home’s entire front stoop was submerged.
Back in 1987, the crest reached 9.9 feet and local officials are using this storm to collect new flood data in order to predict the impact of future events. The removal of the Fairbank and Hofmann dams in 2012 has changed the hydrology of the river, with higher crests now need before severe flooding occurs in Riverside.
“We’re doing a lot of aerial photography with our drone, documenting where we’re at with [a crest of] 10 feet,” said Riverside Fire Chief Matthew Buckley, who said the village has just a few aerial photographs of the 2013 flood.
Although the river did not overtop the bank at the corner of Park Place and Groveland Avenue, both Lincoln Avenue and Groveland flooded, with village closing the storm sewer outfall at Groveland Avenue to prevent the river from back-flowing into the neighborhood.
By late Monday morning after the crest stabilized at right around 10 feet, the village began pumping water from Groveland Avenue into the river to reduce street flooding there.
The river did overtop the bank south of Forest Avenue, inundating lower-level condo units and driveways and flowing into the West Avenue/Pine Avenue area. Public Works Director Edward Bailey said that the flood water reached about a third of the way east down Pine Avenue.
Meanwhile, the Riverside Police Department was forced to abandon its temporary substation at the Scout Cabin as flood waters came up quickly after a heavy downpour early in the evening of May 17.
“We were barely able to get the squad cars out,” said Police Chief Thomas Weitzel.
The river started topping the bank near the Scout Cabin at about 5:30 p.m., said Weitzel, who added that they needed to use the fire department’s boat to reach the Scout Cabin to retrieve equipment and personal items left behind by officers later that night.
By the morning of May 18, the flood water reached into the front yards of some residences across from the Scout Cabin on Fairbank Road, with a swift current racing past in Indian Gardens.
Swift changes on Sunday evening
In at least one respect, the 2020 flood is similar to the one in 2013 in that river levels were already high when the storm May 16-17 dumped an additional 4.6 inches of rain onto ground that was completely saturated from a 2.5-inch rainstorm on May 14-15.
The first wave of rain had swollen the Des Plaines River to flood stage by the time the second wave hit.
“Mother Nature hit us pretty good,” said North Riverside Public Works Director Tim Kutt, who added that he’d never seen such widespread street flooding in that village.
“I haven’t seen this much water on the streets in 33 years,” said Kutt. “I’ve seen a lot of flooding, but not every street and over the curb. I don’t think I’ve seen one worse than this one.”
The first reports of street flooding began rolling in around 4:45 p.m., with Riverside and Lyons shutting down First Avenue between 31st Street and Ogden Avenue just after 5 p.m. due to high water near the railroad bridge.
At about 8 p.m., a motorist went around the barricades and decided to brave the standing water under the bridge. Riverside firefighters rescued him from his vehicle a short time later. The car remained floating around under the bridge well into the morning on May 18.
Other major and arterial streets followed suit. Beginning around 5:45 p.m. and well into the evening, Ogden Avenue flooded. Brookfield closed down the area near Ogden and Prairie avenues for a time when sewers overflowed there.
Washington Avenue began flooding in spots along its length around 6 p.m., with the village shutting down the street at Prairie Avenue, Morton Avenue and Kemman Avenue. The 3500 block of Forest Avenue, despite the new pump station and reservoir, did get water.
The reservoir, according to Village Engineer Derek Treichel was filled to its rim – the first time it’s ever reached capacity since being constructed in the wake of the 2013 flood – by 6:30 p.m. on May 17.
Although Salt Creek hadn’t overtopped its banks in the 3500 block of Forest Avenue, the level of the creek was just inches from doing so by Monday morning. The water level reached the underside of the Washington Avenue bridge, but the structure wasn’t in any danger, according to Treichel, and was not closed to traffic as of May 18.
“We’re monitoring it hourly,” Treichel said.
Other intersections closed to traffic as sewers surcharged on the evening of May 17 included 31st Street and Prairie Avenue and 31st Street and Grand Boulevard. Residential side streets throughout Brookfield also filled with water as sewers surcharged.
Salt Creek did overtop its banks in the vicinity of Southview and Arden avenues in the Hollywood section of Brookfield, and high water forced evacuation of some homes in the Cech Terrace section of Lyons, accessible only through Hollywood.
In Riverside Lawn, the incorporated section of Riverside Township wedged between the river and 39th Street, flood waters reached almost to its southern border. While homes right along 39th Street were spared, those homeowners closer to the river were swamped by flood waters.
Cook County began buying up residential properties and demolishing the homes after the 2013 flood, and most property owners to the opportunity to sell rather than face another one.
A handful of houses remain along Stanley and Gladstone avenues, and nearly all of them were surrounded by water on May 18.