It would cost “hundreds of millions” of dollars to use natural stormwater absorption methods to reduce flooding in areas of Pittsburgh to help comply with a federal mandate to reduce sewage overflow into the city’s rivers, Mayor Bill Peduto said Monday.
But that’s a fraction of Alcosan’s $2 billion to $3 billion proposal to expand its sewage plant and large sewage and stormwater holding tanks under the rivers.
“If we’re able to hold the water where it lands and not put it into the broken system, we won’t need as many pipes,” Peduto said following a public meeting on flooding hosted by Councilwoman Darlene Harris of Spring Hill. “The question is, do we build it with a bunch of pipes, which would be the most costly option, or do we look at common-sense solutions with green infrastructure and lower that total cost.”
If Alcosan and state and federal regulatory agencies approve, the Pittsburgh Water and Sewer Authority’s “Clean and Green” plan would take five to 10 years to implement, Peduto said.
Alcosan is under a federal mandate to cut in half by 2026 the estimated 9 billion gallons of sewage each year that overflows its sewer system during heavy rain and goes into the rivers.
Peduto, Allegheny County Executive Rich Fitzgerald and environmental groups such as the Sierra Club and Clean Rivers Campaign have lobbied for so-called green infrastructure, which would use such things as rain gardens and swales to collect rainwater and let it seep naturally into the ground.
James Stitt, PWSA’s director of planning, said the authority has determined that the city’s most flood-prone watersheds contain about 3,600 acres of rooftops, sidewalks and parking lots that cause rainwater runoff and flooding.
“If we can control about half of it, about 1,800 acres of that impervious surface with green infrastructure … then we will be able to manage a significant amount of the overflow,” Stitt said.
Stitt said the fix would require a series of green projects across the city totaling about 183 acres — about half the size of Allegheny Cemetery. Projects for flood-prone Washington Boulevard alone would cost $76 million to $260 million, he said.
City officials said they will implement better planning and training for public safety personnel to deal with the type of flash flooding that killed four people trapped in their vehicles on Washington Boulevard in 2011.
Public Safety Director Wendell Hissrich said police, firefighters and paramedics have been trained in water rescue and that the city would offer additional training next year.
Public Works Director Mike Gable said the city is working to repair a broken warning system to prevent motorists from driving onto Washington Boulevard during heavy rain.
Gable said warning lights that flash when water on the boulevard rises are now working, but three gates that block streets leading to the boulevard are not yet operable.
Police and Public Works employees have barricaded the streets during recent rains, Gable and Hissrich said.
Bob Bauder is a Tribune-Review staff writer. Reach him at 412-765-2312 or firstname.lastname@example.org.