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Track 1 Day 1: Callahan


Green Stormwater Infrastructure for Combined Sewer Overflow Control

Wednesday March 20, 2019
3:00 to 3:30 pm


Bernadette Callahan, Stantec Consulting Ltd.


The Philadelphia Water Department’s (PWD) Green City, Clean Waters program is a 25-year plan proposing to create, or recreate, natural landscapes to absorb stormwater runoff from impervious surfaces, reduce combined sewer overflows, and to meet regulatory requirements.

Through this program, Philadelphia is meeting the challenge of complying with ever-increasing water quality and quantity requirements and reducing combined sewer overflows, while providing cleaner waterways for its residents. This is not an easy task given the aging infrastructure, regional and global changes such as development and climate change, as well as timing and affordability.

This presentation will provide an overview of the PWD’s ongoing program, discussion of GSI systems designed and constructed to date, and discussion of lessons learned that may be applicable to other jurisdictions. Using select project examples, the presentation will highlight how GSI—specifically, vegetated systems—met stormwater quantity and quality goals while greening neighborhoods, restoring waterfronts, improving outdoor recreation and educational spaces, and enhancing the quality of life for all residents.

In addition, the presentation will stress the importance of both community outreach and community involvement in the ongoing success of these systems and the overall program.


Learning Objectives

1. The audience will obtain an understanding of how green stormwater infrastructure can be used to meet stormwater goals while providing a host of other social, environmental, and economic benefits beyond stormwater management.

2. The audience will obtain an understanding of how Green City, Clean Waters works, unique partnerships/funding opportunities, and the importance of community outreach and involvement for a program of this magnitude.

3. The audience will obtain an understanding of different solutions that are available to address combined sewer overflows, and why Philadelphia chose green stormwater infrastructure with targeted traditional gray infrastructure for their program.


Bernadette Callahan

Bernadette Callahan

For more than a decade, Bernadette has focused much of her attention on urban land development, permitting, and green stormwater infrastructure design (GSI).

Since its inception in 2011, Bernadette has led the Stantec team in our work with the City of Philadelphia Water Department’s (PWD) Green City, Clean Waters program. The initiative represents the largest GSI program ever envisioned in the US, with a 25-year investment of $2.4B from PWD and the Pennsylvania Environmental Protection Agency. It outlines Philadelphia’s long-term plan for the reduction of combined sewer overflows through investments in GSI.

An associate in Stantec’s Philadelphia office, Bernadette is responsible for the planning, design, and management of a variety of public and private sector projects. Prior to joining Stantec, she performed in-house stormwater consulting reviews for PWD.