21 st -Century Water Solutions: How U.S. Cities are Using Green Infrastructure to Curb Stormwater Runoff and Resulting

1. 21st-Century Water Solutions: How U.S. Cities are Using Green Infrastructure to Curb Stormwater Runoff and Resulting Combined Sewage Overflows

2. Stormwater Runoff is a Symptom • Impervious surfaces, and therefore runoff, increase with development • Need to address the problem: development • Green infrastructure practices can address 21st-century development challenges

3. Green Infrastructure is a Solution A cost-effective, sustainable, environmentally friendly approach to wet weather management Benefits include - reduced volume of stormwater runoff - reduced water treatment needs - reduced grey infrastructure needs - reduced flooding - improved water quality

4. Chicago’s Progressive Agenda • One of the world’s largest wastewater collection/Rx systems coupled with development • 1970 start for $3.4B tunnel storing 2.5B gallons • Green Roof program 1+ million square feet • Green Alleys replace asphalt with permeable paving • Green Technology Center

5. Milwaukee Measures its Plan • 14-38% reduction in annual CSO volume with downspout disconnection, rain barrels, and rain gardens in residential areas • 22-76% reduction in annual CSO volume with green roofs, rain gardens, and green parking lots in commercial areas

7. Philadelphia is the Pioneer • Invest more in green than grey infrastructure • Rely on green infrastructure for most of required overflow reduction • Include enforceable requirements for city retrofit • Leverage investments from the private sector to help satisfy pollution reduction requirements

8. Summary of Literature • Grey infrastructure mitigation is limited to end-of-pipe problems • Green infrastructure offers opportunity to develop new areas and retrofit existing developed areas—and provide multiple benefits • Growing evidence that in many cases its equally or more economically efficient