_ECO Water

_Green Infrastructure

Drexel's Franco Montalto is searching for better ways to deal with problematic urban storm water.

_Franco Montalto

Montalto is an associate professor of civil engineering, with research interests in the effects of built infrastructure on societal water needs, green design and more.

Franco Montalto says the “greening” of an urban area can do more for a city than just add aesthetic value. He says it can also provide solutions to major infrastructure problems, especially when it comes to dealing with excess water resulting from stormy weather.

“In a city like Philadelphia, you get a lot of runoff generated, and that gets into the sewer,” says Montalto, a Drexel assistant professor of engineering. “That’ll cause raw waste water to overflow into adjacent rivers and potentially also back up in people’s basements. It’s illegal, and we need a long-term solution for it.”

Thanks to two grants from the National Science Foundation and partnerships with the Philadelphia Water Department and the New York City Department of Parks and Recreation, among others, Montalto is monitoring the impact of urban green infrastructure solutions implemented in Philadelphia and New York, and has even simulated scenarios should the cities continue to expand their green commitments.

Montalto notes that cities such as Chicago, Milwaukee and Portland have implemented multi-billion dollar underground tunnels and tanks to capture the excess runoff. But he says there’s a more efficient—and less expensive—way to deal with excess water.

Philadelphia and New York City have, respectively, committed to retroactively greening about 40 percent and 10 percent of their impervious surfaces during the next 25 years.

Between the two cities, Montalto continues to monitor as many as 25 green infrastructure sites, including so-called “Greenstreets”—vegetated spaces within a city that were historically built for beautification purposes that are now being designed to manage street runoff.

By installing a sensitive scale—a weighing lysimeter—beneath a portion of a Greenstreet to monitor changes in mass, Montalto says he is able to measure directly how much water is actually evaporated from that green space. He already has weighing lysimeters in two different “greened” traffic islands in Queens, N.Y., in Alley Pond Park, one of the last old growth forests in New York City, as well as on a green roof at the Ethical Culture School in Bronx, N.Y. This fall, he will be adding five new lysimeters to the roof of the Jacob Javits Convention Center in Manhattan, which will soon host the second largest green roof in the nation.