Philadelphia Green Streets Design Manual
This is a good example of:A city manual for integrating stormwater management & landscaping into existing rights of way
Philadelphia released a Green Streets Design Manual (Feb 2014) to introduce park-like, functional infrastructure back into the city’s paved landscape. The manual covers a list of suggested practices and the specifications needed to meet multiple goals from myriad agencies that have responsibility over streets.
Philadelphia contains over 2,500 miles of streets that produce large quantities of polluted stormwater runoff. The city decided to use green infrastructure techniques to better manage stormwater runoff with the following objectives in mind:
- To find more cost-effective alternatives to conventional “gray infrastructure” using concrete pipes;
- To better manage more frequent and severe storms;
- To make investments visible at the street level, which is difficult to do with buried pipes;
- To improve transportation networks with more attractive, multiple-duty infrastructure for all travelers;
- To improve air quality and lessen the severity of urban heat island effect that comes with heat waves during summer months; and
- To achieve federal mandates for water quality goals. Philadelphia still handles combined waste water from sewers and stormwater in a single pipe. During heavy rainstorms, this combined water spills into streets and waterways, presenting environmental and health hazards. The city’s green infrastructure approach seeks to reduce the occurrence of these overflows by keeping stormwater out of underground pipes.
Because streets and street design are governed by a varied set of Departments, civic associations, utility providers, land owners and agencies, the key to the success is to develop a seamless process to bring the elements of stormwater management, street engineering and landscape design together to produce a functional, attractive and cost-efficient project.
The Manual presents information on:
- Overview: an introduction to stormwater management and street design in Philadelphia
- Practices appropriate to Philadelphia
- How & Where to locate green infrastructure practices
- Design requirements & specifications
- Implementation, policy and procedure (including maintenance and funding)
The Water Department’s Green City, Clean Waters program includes a 25-year commitment to manage more than one-third of the impervious cover within parts of the City served by combined sewers. The city has a goal of creating close to 10,000 “Greened Acres.” A Greened Acre represents one acre of impervious cover that is retrofitted with green infrastructure and can manage at least the first one inch of stormwater runoff.
Practices: The design manual provides flexible design guidance for eight types of practices: stormwater tree trenches, stormwater trees, three types of stormwater bump-outs, permeable pavement, green gutters and stormwater drainage wells.
Application: The manual not only shows practices, but also depicts how practices can be applied in Philadelphia neighborhoods:The city allows non-government entities (i.e. developers) to design and construct green infrastructure practices within the right-of-way (a green street); once built, they are with accepted by the Water Department.
URL link to Main Resource:http://www.phillywatersheds.org/what_were_doing/gsdm
Project Location :Philadelphia, Pennsylvania, US
Stage:City of Philadelphia, Philadelphia Streets Department, Philadelphia Parks & Recreation, Philadelphia City Planning Commission, Pennsylvania Department of Transportation (PennDOT)
Steering Committee: Pennsylvania Environmental Council, Delaware River Waterfront Corporation , Philadelphia Horticultural Society, Old City District, Philadelphia Department of Licenses and Inspections, Southeast Pennsylvania Transit Authority (SEPTA), PGW, PECO, Philadelphia Fire Department