It has taken nearly three years, but Philadelphia’s ambitious plan for controlling stormwater has just won approval from the state Department of Environmental Protection. The city’s 25-year, $2 billion plan aims to reduce rainwater runoff into sewers by 85 percent largely using “green infrastructure,” but at a cost to ratepayers.
Philadelphia, like many older cities on the East Coast and in the Midwest, has a combined sewer system, which means rainwater flowing through storm drains ends up in the same pipes as raw sewage. While it’s supposed to go through sewage-treatment plants to get cleaned up, it often doesn’t.
“When it rains, even the tiniest amount, those pipes can overflow very quickly,” said Howard Neukrug, Philadelphia Water Department Commissioner.
That overflow means raw sewage bypasses treatment facilities and flows straight into area waterways, including the Schuylkill and Delaware rivers.
Federal order to reduce runoff
Ten years ago, Congress told cities with combined sewer systems to come up with plans to reduce that runoff. For most cities, that meant installing more pipes and beefing up sewage-treatment facilities. Philadelphia is also taking those measures, but the core of the city’s plan is different.
“We’re going to be looking to use our funds that normally would be spent to expand sewer systems but instead reduce demand on the existing sewer systems,” Neukrug said.
Reducing demand means helping the ground absorb rain again, as soil naturally did before asphalt and cement covered urban areas. The city’s plan includes using porous pavement instead of standard asphalt, planting rain gardens and sidewalk containers full of water-absorbing plants, as well as installing rain barrels.
It has already planted gardens at some playgrounds and installed underground tree irrigation systems around the city, but with official approval the city said building a “green infrastructure” can begin in earnest.
Greener by a third
“In all, we’re going to green one-third of the city of Philadelphia over the next 20 years,” Neukrug said. “It’s quite a big challenge that we have in front of us.”
The individual techniques the city is using aren’t new, but the breadth of the plan is.
“Philadelphia is the first city in the country to attempt to use green infrastructure on a city-wide scale as the core of their approach to dealing with sewer overflows,” said Larry Levine of the Natural Resources Defense Council a national nonprofit. “It puts Philadelphia on the leading edge as a city that others should look to.”
The plan calls for keeping 85 percent of rainfall out of the storm sewers.
To fund the so-called “Green City, Clean Waters” initiative, the Philadelphia Water Department expects to hike rate-payer’s water bills 2 and a half percent each year. It has already begun charging businesses different rates, depending on how much runoff their properties produce.