Better coordination between transportation planners and utilities’ stormwater management is the aim of a new guide produced by the National Association of City Transportation Officials (NACTO).

The Urban Street Stormwater Guide is meant to be a resource for city engineers and policymakers to use to do a better job of incorporating green infrastructure into redesigned streetscapes and other transportation projects. While there are many how-to technical guides on installing green infrastructure, few focus on exactly how to best integrate those features alongside the necessary transportation components on a street, says Corinne Kisner, NACTO’s director of policy and special projects, in a report by Governing magazine.

“This is becoming an increasingly urgent problem in cities nationwide and worldwide, frankly,” she says of managing urban runoff.

NACTO developed the guide with input from transportation and water experts in several cities, and it includes examples of how different cities have tackled the green infrastructure component in transportation projects. For example, during construction of a light rail project that connected the downtowns of Minneapolis and St. Paul, the two cities planted 1,000 trees and included gardens and other features to absorb rain along the route. Officials estimate that it cuts stormwater runoff in half.

But NACTO’s guide also focuses on how green infrastructure works best in a comprehensive approach throughout a city, rather than just an add-on to an individual project. Philadelphia’s water utility was involved in the development of the guide and is also a perfect case study, as it has worked alongside the city’s streets department since 2011 to complete 124 different green infrastructure projects, which have turned 550 acres of impervious surfaces into an area than can now handle as much as 1.5 inches of runoff.

“The key seems to be advanced planning and coordination, as public projects can take years to design, bid and construct,” Joanne Dahme, of Philadelphia’s water department, told Governing magazine. “Syncing up our needs with those of other public agencies and private agencies can be challenging. But with experience, we improve.”

Kisner notes that installing green infrastructure is often well worth the initial investment.

“What’s neat about stormwater infrastructure, though, is it’s one of the few assets that really appreciates over time,” she told Governing magazine. “As the plants establish themselves, they can absorb more stormwater, which can be really beneficial.”

Source: Governing magazine