The sewer system in Calumet City needs upgrades, the city engineer said Tuesday, but he said no infrastructure could handle the deluge that hit areas of the south suburbs Sunday.
“We’re looking at almost 9 inches in a little less than 3 hours,” said Ken Chastain, Calumet City’s engineer. “We’re looking at flooding that never occurred (before) in Calumet City.”
The rain overwhelmed the city’s ancient sewer system, and the water filled streets and basements, although it was not immediately clear how many properties were affected. Chastain said flooding affected all seven of the city’s wards.
“It was a 500-year event over an extremely small area,” he said, indicating that type of storm is exceedingly rare. “It was an incredible amount of rain.”
National Weather Service radar estimates show between 8 and 10 inches of rain fell in and around Calumet City.
In South Holland, 5.7 inches were measured and the service reported rainfall of 5 inches in Harvey and a bit more than 4 inches in Oak Forest. Other suburbs such as Hazel Crest and Phoenix recorded 4 inches, according to the service.
Any assistance from the federal government for affected residents and business owners would take an emergency declaration from the governor and presidential approval, according to the Federal Emergency Management Agency.
FEMA opened a temporary disaster recovery center Sept. 14 in Calumet City to assist residents affected by storms that moved through central Illinois and the Chicago area and caused flooding June 29 through July 2.
The worst of the floods earlier this summer happened in suburbs such as Cicero, although Calumet City saw some flooding problems as a result of the storms, Chastain said.
FEMA’s Calumet City office is open through Thursday, with personnel able to help with things such as applying for grants for home repairs and low-cost loans to cover uninsured property losses, according to FEMA. The office is open to any Cook County resident impacted by the late June flooding.
The office isn’t able to assist with residents affected by Sunday’s storms under the current emergency declaration, according to Nicole Wilson, a FEMA spokeswoman.
Gov. J.B. Pritzker’s emergency declaration that covered the late June storms was approved by the Biden administration in August. It would take another such declaration to free up federal help for this weekend’s flooding, she said.
In the meantime, she said FEMA advises impacted property owners to record any damages, including taking photos, and keeping receipts of work done to remediate damage.
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Chastain said Calumet City’s sewer system couldn’t handle the amount of water that fell in such a short time, and the city has proposed fixes carrying a price of more than $100 million, including new sewers and stormwater detention ponds.
“Nothing could be designed for that,” he said of the Sunday storm.
South Holland saw an “unprecedented rainfall, with an astonishing 6 inches of rain falling in just 2 hours,” Julia Huisman, a village spokeswoman, said Tuesday.
Flooding caused some temporary street closings, and the village received 30 calls from residents who had water in their basements, she said. Some of those were due to lack of overhead sewers or failed sump pumps, she said.
The Metropolitan Water Reclamation District said despite the heavy rainfall totals, its reservoir at the Thornton Quarry was just a bit more than 12% full, holding just under 1 billion gallons. The reservoir has a capacity of nearly 5 billion gallons, and holds a combination of stormwater and sewage, as many communities served have combined sewer systems.
The district said “few local sewers have capacity to handle these rain totals” and move the water into the district’s Deep Tunnel system, of which the Thornton Reservoir is part.
Chastain said Sunday’s rain and subsequent flooding impacted all of Calumet City’s seven wards, “which was very unique.” Three quarters of the city’s sewer system uses combined rain and sewage lines.
He said there are “systemic, structural deficiencies” in the city’s sewer system that Calumet City is seeking outside funding to correct.
Chastain said while major storm events causing flooding used to be uncommon, “they’re going to happen with climate change more often,” and that Calumet City and other municipalities need to cope with them.