Green City, Clean Waters Promo from GreenTreks Network on Vimeo.

Big news! On June 1st the City of Philadelphia and the Philadelphia Water Department [PWD] signed an ambitious agreement to authorize PWD to use green infrastructure strategy to reduce combined sewer overflows and improve water quality in the surrounding waterways.  This effort is part of their Green City, Clean Waters Plan.

This initiative authorizes PWD to spend around $2 billion on green infrastructure projects over the next 25 years. These could be anything from tree-and-stormwater plantings, to rain gardens, to porous pavements, and more — anything that helps capture, store, and/or infiltrate rainwater on-site.

Philadelphia is currently out of compliance with the Clean Water Act’s TMDL regulations. When they did a cost benefit analysis of their needs and potential solutions, however, they realized that they could not build and pipe their way out of their stormwater problem. Piping out every drop of runoff from the entire city of Philadelphia is simply not sustainable with their current tax base.

The city already has an existing gray infrastructure system for emergency flooding; in order to increase the total (grey and green) system capacity, funneling $2 billion in to green infrastructure is actually the least expensive option. According to a press release from the city, “PWD has softly launched the plan over the last few years to develop green infrastructure designs that work best in the Philadelphia landscape. These early projects serve as public demonstrations for citizens and provide the PWD and its many partners with early opportunities to monitor and improve the efficiencies of these practices.” Featured projects can be seen here.

In order to reach this momentous agreement, Philadelphia had to reconceive their stormwater problem as a stormwater opportunity (corny, perhaps, but true). Instead of treating stormwater as a waste product to discharge, they recognize stormwater as an asset to water plants, restore soils and recharge their groundwater. Trees get much larger, and more plants flower and wildlife habitat is protected and enhanced. With these changes come improvements in air quality, property values (and a greater tax base…), safety, and summertime temperatures. Philly has decided to “wet its uplands” again, and they will reap incredible benefits and savings as a result.

Naturally, we’re very excited by this. Among other things, this agreement signals the significance of green infrastructure to municipalities throughout North America and adds further credibility to an already-strong movement toward sustainable design and low-impact development. Congratulations are due to the City of Philadelphia and the Philadelphia Water Department for championing this extremely important initiative.

We believe that green infrastructure has come to the rescue just in time for Philly. Our hope is that big street trees are the beginning of fulfilling that promise.