What's causing Route 28 to flood? PennDOT might have found the reason

PennDOT is investigating the possibility that illegal dumping in Pittsburgh’s Troy Hill neighborhood is behind recent flooding along Route 28 near Pittsburgh’s 40th Street Bridge, an official said Monday.

Cheryl Moon-Sirianni, PennDOT’s District 11 executive, said crews were in Troy Hill Monday to see whether a report of illegal dumping is true. They’re also checking to make sure storm pipes draining into the Allegheny River are clear.

Moon-Sirianni said the flooding is happening during heavy rain at the site of the former Millvale Industrial Park that was demolished as part of a $180 million reconstruction of Route 28. The project wrapped up in 2014.

Officials have attributed the flooding to silt and debris running off a hillside and clogging drainage ditches on the hillside and a drain for a stormwater retention pond along the highway. Troy Hill sits atop the hill.

“We’re hearing potentially there might be some dumping that’s occurring at the very top of the hill that’s either clogging or burying the inlets,” Moon-Sirianni said. “I don’t have the answer to that yet.”

She said crews were on scene Monday to inspect the entire hill in an attempt to pinpoint the problem.

Route 28 was closed for most of the day Thursday between the 40th and 31st street bridges after a storm dumped more than 2 inches of rain on the region. Traffic backed up for miles, leaving motorists stranded for several hours. It marked the second time in two months that the road flooded.

Drivers caught in a similar flood May 29 had to be rescued by first responders after their vehicles were trapped in the water.

“Our environmental and maintenance folks are working on a solution,” Moon-Sirianni said. “They’ve reviewed it. They have some ideas. They’re looking to make sure what the problem is first before fixing it.”

Engineers on the Route 28 reconstruction designed a series of drainage ditches and inlets to capture stormwater running off the hill, and Moon-Sirianni said the system should work well.

“We thought our design was going to work well and I do think that, once we find a solution, the design is a solid design,” she said.

She speculated that the fix could be more frequent cleaning of the retention pond and drains. It also could include placing larger rocks to line the drainage ditches.