GREEN STREETS Lessons Learned from Philadelphia and New York City November 16, 2015 Maine Stormwater Conference.
Acknowledgements Jillian Simmons, PWD Sufian Khondker, Arcadis Mike Moscariello, Arcadis Anwer Ahmed, Arcadis Mark Van Auken, Arcadis Fernando Pasquel, Arcadis
Outline Program Objectives Drive Standards Implementation Approach Design Methodology Site Considerations Aesthetics / Landscape Construction / Maintenance
Why Target Public Right-of-Way? Streets represent: A large portion of City owned impervious area Retrofit opportunities Control Access
Program Objectives Drive Design Standards New York City Program: Manage 1 stormwater runoff from 10% Impervious Surfaces in combined sewer areas system-wide, focus on high concentration in CSO priority areas Implementation Approach Standardized ROWB and Green Streets designs Design Methodology Systems designed for storage/infiltration; no underdrain connections Site considerations Focus on street projects and pilots for schools, public housing and other city properties Landscape Standardizing plant palette based on performance Construction Oversight is key, many projects are bid with construction as part of CM contracts
Program Objectives Drive Design Standards Philadelphia Program: Manage runoff from ~40% of impervious surface in combined sewer areas Implementation Approach Standardized process Design Methodology Maximize capture/storage volume; always include underdrains Site Considerations - Need to look at all GI opportunities across entire CSO area Landscape Standardizing plant palette based on performance Construction Oversight is key; ongoing education and outreach with construction inspectors and contracting community
Implementation Approach Standardization to facilitate implementation Failure and success are learning opportunities Leverage funding Set up project tracking systems early Images: Standardization of design resources on Philadelphia Water Department website. Standard NYC ROWB.
Logging & Tracking Spreadsheet
Potential ROWBs
Design Methodology Understand the regulatory requirements Stormwater quantity/quality LTCP requirements TMDLs Incorporate redundancy Stone columns in NYC Underdrains in Philadelphia Images: Stone columns used in NYC to promote infiltration. Underdrain depicted in rendering of stormwater tree trench Stormwater bumpout with prolonged standing water.
Design Methodology Keep it simple Include a safety factor to allow for flexibility during construction Design for full surface elevations Looks for innovative solutions and use project team s experience (ET, Inverted canopies) Images: Standard NYC ROWB detail. Rendering of stormwater curb extension in Philadelphia
Site Considerations Know your existing conditions, consider site history Factor site usage into BMP selection Perform comprehensive geotechnical investigations and locate all utilities Images: Tablet-based application for field verification in NYC. Interpreting GPR imagery in NYC. Historical graveyard discovered during excavation of a rain garden in Philadelphia.
Utilities
Aesthetic / Landscape Limit plant lists based on past performance Include a maintenance warranty, be prepared for plant replacement Include aspects that provide a public benefit Reuse existing materials and native plants Images: Philadelphia rain garden with creative reuse of concrete pathways in riprap. Naturalized landscape design in Philadelphia rain garden.
Construction Translate lessons learned during construction into design improvements Proper construction and inspection is critical Consider timing, phasing and seasonal restrictions Images: Construction of stormwater tree trench in Philadelphia (left). Empty stormwater planter in late fall (right).
Maintenance & Performance Think about maintenance at beginning of project inflow, outflow and landscaping Incorporate access vehicular and pedestrian Keep systems offline during plant establishment period Design appropriate energy dissipation Images: Blocked off trench drains to a rain garden (left). Large rock splash pad in rain garden (right).
Summary Political support Significant investments Well structured programs Adaptive management approach
Fernando Pasquel Arcadis fernando.pasquel@arcadis.com 703 842 5621 Mark Van Auken Arcadis mark.vanauken@arcadis.com 330 515 5678 Thank You. Nobember 16, 2015 18