By Matt Peterson

PHILADELPHIA (CBS) — Storm water runoff from rain and thunderstorms is the number one cause of pollution to waterways in urban environments. And in an old city like Philadelphia, where a combined sewer is used, the city’s water department is taking steps to keep the water clean.

“What this program does is try and capture all of that rainwater and either recycle it or release it over a slower period of time, so that we never bypass the sewer treatment plants and that really is a powerful thing in reducing downstream pollution,” Douglas Carney, Senior Vice President for facilities design and construction, said.

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Each time Philly gets a rain storm, water is collected and stored in a facility at Children’s Hospital of Philadelphia. It’s then recycled and used to water the plants and trees in the rooftop and ground level gardens.

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So far in August, Philadelphia has received just shy of three inches of rain. But that’s just a drop in the bucket for a system that can hold up to 100,000 gallons of water or 100 percent of the water that hits the site.

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The design is award-winning beside CHOP’s sixth floor outdoor garden. Designers also built an underground parking garage with a 2.6 acre green roof on top.

It’s not only beautiful, it also allows easy access for the public, employees and most importantly, patients.

This outside-the-box thinking won the hospital the 2017 “Stormwater Pioneers” Award.

“The greatest thing about receiving that award from the City of Philadelphia was getting recognition from the Water Department and the city that CHOP is a thought leader like all of our physicians are in the clinical areas, but also in the area of sustainability and preserving the natural resources for future generations,” Carney said.

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CHOP hopes the example they set with the Buerger Center will be an inspiration for sustainability not just in Philadelphia, but across the country.