Why St. Louis sees street ‘geysers’ during flash floods


ST. LOUIS – FOX 2 News has obtained more incredible video documenting St. Louis’s ‘geyser’ problem.    As seen again this week, the city’s ancient sewer system can blow holes in streets and pop manhole covers during flash floods.    

A video from 2018 shows air and water pressure from flash flooding exploding large portions of pavement on Rutger Street just south of Downtown. One can hear chunks of pavement raining down on a nearby car.   

Video from the same spot last year shows new manhole covers popping up and down, releasing the air and water pressure in spurts during another flash flood event, with no more explosions.  

“Basically letting the sewers breathe is what we’re doing,” said Sean Hadley, a spokesman for the Metropolitan St. Louis Sewer District (MSD).   

The covers are on hinges and are too heavy to lift without tools. Barriers prevent people from parking over them on the low-traffic side street. Grates have also been added for additional drainage and venting. 

The $45,000 worth of improvements are a much better alternative than the costly street and car repairs, let alone potential injuries.    

“We came out and we put some vents in,” Hadley said.  

“We installed some new, hinged manhole covers so, when that air pressure and all that water lifts, it pushes the manhole cover up slightly. It lets the air out. It lets the pressure go out and then water can subside and go where it needs to go.” 

There are at least 5-6 other places in the city where the ‘geyser phenomenon’ has been reported, according to MSD.   

The lessons learned on Rutger Street should help fix the problems everywhere else. The intersection of Arkansas and McKean in south St. Louis is a repeat offender.   

Resident Sacha Heath caught video of geysers this week and a year ago, in the exact same spot.   

“You hear the water exploding. It sounds like steam. Then chunks of asphalt are flying in the air,” she said.  

Much of the newer stormwater and sewage system feeds into centuries-old ‘brick’ portions, Hadley said. When the pressure escapes through the brick joints, it can lead to exploding pavement during hundred-year flood events like there was this week.   

Prior to people capturing these ‘geysers’ with their cell phones, they may have been dismissed as an urban legend, a long-time MSD worker said.  

The videos are also critical in coming up with solutions.   

For instance, the hinged manhole covers and parking barriers on Rutger Street won’t work for the high-traffic intersection at Arkansas and McKean.   

The videos give MSD engineers a precise location where the problems occur and give them a place to start when it comes to stopping the geysers for good.   

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