PHILLY SHOWS CHICAGO A GREEN ER WAY TO MANAGE STORM WATER
Philadelphia has more to teach Chicago than the right way to make cheesesteaks. It also has set an example in stormwater management the Chicago area should follow to reduce flooding, make water ways cleaner and give a welcome economic boost to struggling communities.
In every election cycle, including the recent Illinois primary election, some candidates for the Metropolitan-Water Reclamation District talk up the need for reducing storm water runoff without building bigger sewers or more costly treatment plants. It’s called “green engineering.”
But time after time, too little is accomplished before the next election cycle rolls around. Rainwater that would soak into the ground in a natural setting instead falls on impervious pavement or buildings and flows directly to the nearest waterway or basement. Basements flood, and overwhelmed treatment plants release untreated wastewater into Chicago area waterways.
It doesn’t have to be that way. Philadelphia is a river city like Chicago that also has large swaths of older neighborhoods crisscrossed by “combined” sewers, which carry both rainwater and sewage. As in Chicago, that means when increasingly heavy storms overwhelm the treatment system, the overflow into waterways carries untreated sewage and polluted runoff.
But instead of building larger sewers and new treatment plants, Philadelphia decided to put its chips on what environmentalists call nature- based infrastructure. It has built hundreds of subsurface storage projects, rain gardens, planters, stormwater tree trenches, porous pavement projects, swales and green roofs that reuse stormwater or intercept it and let it absorb into the ground or evaporate.
Seven years into its 25- year “Green City, Clean Waters” project, the city’s green engineering system now manages to keep 1.5 billion gallons of polluted water from running each year into the Schuylkill and Delaware rivers and smaller waterways. By the time the project is completed, planners hope to add another 6 billion gallons of retention, reducing stormwater pollution by 85 percent and making the rivers fishable and swimmable.
In the MWRD’s service area, which has roughly the same borders as Cook County, scattered green infrastructure has been installed in parks, forest preserves, municipalities, schools, alleys and parking lots. The MWRD has given away free rain barrels, and at the Chicago Flower & Garden Show this month at Navy Pier, the agency showed off its green infrastructure techniques to the public. But so far, its efforts, along with those of municipal governments, amount to little more than a drop in a bucket.
Partly that’s because the MWRD’s focus has been on completing its decades- long Tunnel and Reservoir Project, a monumental “gray engineering” undertaking that, when finished, will divert billions of gallons of stormwater into tunnels and reservoirs after heavy rains. The water remains there until it can safely be pumped out and treated, and TARP already is making a significant difference. But engineers say more must be done to address remaining flooding issues.
Additional gray engineering won’t be the answer. Federal and state dollars to help pay to expand treatment capacity and replace old sewers have dried up. Going forward, the MWRD and local municipal water agencies need to get better at green engineering.
Philadelphia does it by placing strict requirements on new construction, retrofitting public property and using financial incentives to encourage private landowners to retrofit their property aswell. Commercial land owners whose bills once were based on meter- recorded water usage noware charged for how much water runs off their property. Bills are reduced if landowners install green infrastructure, and the city offers grants to help pay the cost of installing it.
To keep the program effective, the Philadelphia Water Department monitors the maintenance and performance of green infrastructure on both public and private land.
The additional green spaces created as part of green engineering mitigate against asthma attacks and heat stress and help the ecosystem and make the city more vibrant. The decentralized nature of green infrastructure has made it easier for the city to steer maintenance and other work to a variety of startup businesses that are owned by and employ minorities, women and the disabled. Those businesses also bring revenue to disadvantaged neighborhoods, officials say.
Philadelphia has two structural advantages thatmade it easier to create a large green infrastructure program. Unlike the Chicago area, where the responsibility for stormwater management is shared by the MWRD and dozens of municipalities, it has a single agency in charge. The Philadelphia Water Department also does its own billing, which makes it easier to reduce bills in exchange for the installation of green infrastructure on private property. In the Chicago area, sewage treatment costs are lumped into property tax bills along with schools and other local governments.
Those are hurdles that can be overcome. The Chicago area is ahead of Philly in gray engineering, but it sure needs to catch up on the green variety.
Philadelphia has built hundreds of subsurface storage projects, rain gardens, planters, stormwater tree trenches, porous pavement projects, swales and green roofs.