The rain poured down last Thursday for about four hours, dumping as many as seven inches of water in some parts of the Akron area. The slow-moving storm resulted in a “very, very, very heavy rainfall in a very short period of time,” said Raelene Campbell, a meteorologist with the National Weather Service.
“When you’re dumping that much water, things can easily get overwhelmed,” Campbell said.
And that’s exactly what happened. The resultant flooding closed roads, stranded cars and left businesses and residents cleaning up a sudden influx of water and mud.
Could the city have prevented some of the fallout?
It’s possible, said Rob Scarlatelli, the water reclamation services manager for the City of Akron. But such an effort includes a cost.
The city’s stormwater capacity is currently built for a once-every-decade storm — or a storm that has a 10% chance of coming each year. That means storm sewer pipes in residential neighborhoods tend to have a 12-inch diameter.
Those pipes could be made bigger, Scarlatelli said, but they’re also more expensive. A 12-inch storm sewer costs about $175 a linear foot to install; going up to a pipe with an 18- or 24-inch diameter — and more capacity — could cost between $200 and $250 a foot.
“You have to decide, is it worth designing for an event that’s not the norm?” he said. “What is the right design to design it to? How big is big enough?”
The last time the city experienced a similar flooding event was more than a decade ago, in 2013.
By Scarlatelli’s calculations, this was a once-in-500-year storm — a calculation that means there was a 0.2% chance that the rain would come so heavy, and so fast, regardless of how many times a century it happens.
“It seems to happen more often than the numbers would show,” Scarlatelli said.
Can Akron protect against the fallout of extreme rain events?
Campbell called last week’s storm “super problematic” because it sat over an urban area without much green space to absorb the water, sending the rain into creeks that overflowed their banks.
“There was little to no flow; it just did not move,” she said. “It was sitting right there and dumping in one spot. There was no moving of the storm.”
Across the footprint of the National Weather Service’s Cleveland office, which goes from Toledo to Erie, Pennsylvania, and south to Mt. Vernon and Canton, Campbell said there are typically one or two similar flooding events each year.
Scarlatelli said the west and northwest sides of Akron were hit the hardest. The city showed an accumulation of 4.1 inches of rain in two hours at a Copley Road rain gauge and 3.52 inches in two hours in Merriman Valley. Over the course of the evening, 4.5 inches of water fell at Copley Road and 5.2 inches fell in Merriman Valley.
Scarlatelli said when new properties are built in the city, they’re required to have onsite water retention to help mitigate some of the effects of building.
That helps, he added, but “there’s really not a lot you can do. There really isn’t.”
Summit Metro Parks works to increase ability to absorb rainfall, slow down waterways
At Summit Metro Parks, planners are doing what they can to help improve the capacity for water runoff that makes its way into local parks. Mark Szeremet, a park planner and the interim chief of planning, said the park system recently worked to increase wetlands and slow down rushing rivers at Sand Run Metro and Cascade Valley Metro parks.
Most of the work proved to be successful in last week’s storm, he said. While there was some mud, water and debris in a parking lot off Cuyahoga Street, near the newly restored barn, Szeremet said it was easily cleaned up the next day in time for an event reservation at the barn.
Szeremet said the damage at Sand Run Metro Park was minor as well, so they “feel good about it.”
“Instead of doing something major, like a road reconstruction or a trail reconstruction, we’re just really moving some rock that moved during the storm back into place,” Szeremet said.
Improved culverts — which allow water to flow under roads and trails — are no longer channeling water to specific points, Szeremet said, but allowing streams and rivers to meander more and create their own paths. The park system has also worked to allow waterways to meander more, which slows down the water and helps reduce erosion. There are also more than 100 acres of new wetlands, giving water somewhere else to go for large storm events like the one last week.this one.
That’s a good thing, Szeremet said, because the park system is expecting more large rain events more often.
“I think climate change is doing that,” he said. “I don’t think we’re surprised anymore. You just wait to see what it looks like in the morning, when the light comes out.”
He said the improvements the parks made were largely enough to contain last week’s storms. “The rain that came down was so isolated,” he said, “that certain streams took on a lot of water, and other streams took on no water. So when it hit the bigger watershed, everything seemed to work out.”
But “if we got two more inches of rain,” he said, “who knows?”