Instead of sending all of its storm water straight down the sewer and into the river as quickly as possible, Philadelphia is re-imagining itself as a leader in urban water management. The city is planning to spend $1.6 billion over the next 20 years to overhaul its methods of dealing with the billions of gallons of rainwater it receives each year.
“This is the most significant use of green infrastructure I’ve seen in the country, the largest scale I’ve seen. We commend Philadelphia for breaking the ice.” – Jon Capacasa, Environmental Protection Agency
Rainwater runoff tends to overwhelm the storm water system, sending raw sewage directly into the five rivers and creeks which surround the city, because the sewer system combines the runoff from streets and wastewater with water from bathrooms and kitchens. What’s needed is a way to absorb or slow down the runoff to ease the pressure on the sewer system.
The city’s proposal will use rain gardens, porous pavement, green roofs, and additional tree planting to deal with the water. According the Philadelphia Water Department, implementing these changes will generate more jobs and higher property values, as well as decrease the energy used.
The plan (3,369 pages long) is still being analyzed by environmental experts and regulators, with the EPA having the final say on it. According to the Natural Resources Defense Council’s water expert, Nancy Stoner, the plan is workable in theory, but “It’s the scaling up that’s new. That’s what’s really exciting.”
In dealing with the water from a traditional way of thinking, the city would have had to build massive underground tunnels, expand the city’s sewage plants, or separate the storm-water and sanitary water lines. Aside from being inefficient, those methods would have been extremely expensive and involved the massive reconstruction of 1600 miles of pipes.
Philadelphia’s plan is to replace much of the concrete and asphalt along streets and parking lots with permeable pavers, rain gardens, and mini-wetlands, slowing down the flow of runoff and keeping the water from rushing straight down the storm drains and overloading the sewer system.
The newest storm water plan, which has taken about 12 years to complete, will reduce overflows by 80%, and the reception it has received from many residents has been very positive. Originally the city was looking for three neighborhoods to partner with and have a few blocks rebuilt, but because of such a positive response they are working with 14 neighborhoods.