Urban Stormwater Retrofit Program Highlights

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1 Urban Stormwater Retrofit Program Highlights Delaware Estuary Environmental Summit 2007 Prepared and Presented by: Liz Feinberg Project Funding: William Penn Foundation PA Coastal Zone Management Program

2 Conventional stormwater management......focuses on rate control largely ignoring quantity and quality Concrete channels flush stormwater quickly to a basin s outfall rapidly discharging large volumes of unfiltered stormwater directly into streams. Uncontrolled stormwater picks up pollutants in its path eroding land and stream banks on route.

3 Eroded Streams and banks Impaired Streams Impacts of Uncontrolled Stormwater Management Reduced Base Flow & Dry Streambeds Economic Damage & Public Safety

4 Stormwater Best -- Better -- Management Practices Objectives: Retain stormwater by holding it onsite longer Infiltrate stormwater into the ground Evaporate stormwater into the air Disperse/ Diffuse/ Divert stormwater Filter runoff to reduce pollutant loads Prevent stormwater runoff pollution Protect natural hydrology Restore hydrologic conditions

5 The Big Challenge... Southeast Pennsylvania is developed and urban; therefore, improving stormwater management means... STORMWATER RETROFITS

6 PEC s Stormwater Retrofit Technical Assistance Program Worked with over 50 sites in 25 municipalities Developed retrofit concepts for 15 sites in Darby- Cobbs, Chester-Ridley-Crum and the Neshaminy watersheds Retrofit design concepts incorporate BMPs into existing developments Design Team: Borton-Lawson Engineering and Cahill & Associates

7 Basin Retrofit Design Concept Retrofit Concepts: Remove channels Install earthen berms to extend flow path Construct forebay Raise orifice to retain small storms Replace turf grass with native plants Other Retrofits: Install level spreader

8 Stormwater Basin Retrofit Concepts Naturalizing an existing basin Weir plate on outlet control structure can be a cost effective basin retrofit

9 Parking Lot Retrofit Urban Case Study Site: Norwood Borough, Municipal Parking Lot

10 Retrofit Concept Site: Norwood Borough Recommendations: Create one-way traffic pattern to reduce drive aisle width Install 10 wide Vegetated Bioretention Island

11 Bioretention / Bioinfiltration BMPs Cahill & Associate s design detail. Example of Bioretention Island using curb cuts

12 Parking Lot Retrofit Urban Case Study Site: Yeadon Borough Municipal Building & Lot

13 Retrofit Concept Site: Yeadon Borough Hall Recommendations: Install Porous Pavement and Subsurface Infiltration Bed Connect downspouts to Subsurface Infiltration Bed

14 Example: Parking Lot Infiltration Trench Stone Infiltration Trench conveys runoff into subsurface storage/infiltration bed

15 Urban Stormwater Retrofit Case Study Site: Rutgers Avenue School, Swarthmore Borough

16 Retrofit Concept Site: Rutgers Avenue School,Swarthmore Borough Recommendations: Excavate Infiltration Trenches on existing parking lot Disconnect Downspouts into a Rain Garden Install Subsurface Infiltration bed below football field

17 Retrofit Concept Site: Second Ward Park, Upper Darby Twp. Recommendations: Porous Pavement basketball courts and subsurface Infiltration Bed Tree Trench to capture runoff and provide subsurface storage, infiltration, & biofiltration Basin designed as Rain Garden / Biofiltration Area

18 A Retrofit Demonstration Site: Ward Two Park, Upper Darby Township Project completed Fall 2006

19 Retrofit Concept Site: Folcroft Industrial Park, Sharon Hill Borough Recommendations: Stormwater Filters Rain Gardens /Biofiltration Areas Bioretention Swales Landscape Restoration Level Spreaders at outfall pipes

20 Other BMPs: Non-Structural BMPs Good Housekeeping and Pollution Prevention BMPs Clean Streets Clean Streams

21 BMPs have multiple benefits Control erosion and sedimentation Filter runoff non-point pollutants Increase infiltration and groundwater recharge Stabilize stream flows Protect streams from thermal impacts of runoff Enhance landscapes Provide natural habitat

22 Improved Stormwater Management restores, protects, and enhances creeks and rivers in the Delaware Estuary

23 Thank You!