Municipal officials hope to submit a final “green first” plan for dealing with the region’s stormwater management problem to the U.S. Environmental Protection Agency by the end of this year.
The plan relies heavily on green infrastructure, which involves planting trees and restoring the natural water cycle.
“These are ecologically engineered systems that would deal with stormwater in a more naturalistic way and deal with the stormwater at the source where it falls, where it collects in a more distributed manner across the city,” said James Stitt, manager of sustainability at the Pittsburgh Water and Sewer Authority.
The traditional gray infrastructure approach revolves around channeling water into sewer systems.
City of Pittsburgh Chief Development Officer Kevin Acklin said that approach has led to flooding, sewer backups in residents' basements and sewage making its way to the rivers, resulting in violations of the federal Clean Water Act and a subsequent consent decree between the Allegheny County Sanitary Authority and the EPA.
The original plan submitted to the EPA used a “gray first” approach, adding more pipelines and holding tanks for stormwater. Acklin said it also would have required substantial disruption of the city’s riverfronts where development is booming.
“(A green first approach) allows us to leverage development in neighborhoods that have been disinvested to seed further investments,” he said. “It improves air quality and heat indexes in the city when you have more green infrastructure, and just enhances the overall quality of life in the city while solving a major stormwater problem.”
The plan identifies several watersheds around the city that could most benefit from green infrastructure investment.
For example, much of the rainfall from Oakland, Squirrel Hill and Greenfield ends up in the small, low-lying neighborhood of Four Mile Run, just south of Schenley Park. The plan calls for using the park as a “green sponge,” said Stitt, and could involve constructing wetlands and restoring the Panther Hollow stream channel.
Acklin said green infrastructure is less expensive than gray, causes less disruption for residents and commuters and beautifies neighborhoods.
In Schenley Park, the Pittsburgh Parks Conservancy worked with the city to establish a hillside flower meadow which absorbs rainwater from Squirrel Hill that used to drain into sewer pipes.
“Amenities and features within the parks that people would like to see and would like to have in their neighborhoods can be built as part of these projects so that they’re getting a lot more out of green infrastructure than flood control and stormwater management, even though that is an important driver too,” said Heather Sage, director of community projects for the Conservancy.
Stitt said small projects such as these throughout the city and county will have a huge impact on the amount of water making its way into the region’s aging sewer system.
“Every drop counts,” he said.