Green Infrastructure Typical Details and Specifications for San Francisco — Review of the Development Process and 3 years of Lessons Learned
The Wastewater Enterprise Urban Watershed Management Program of the San Francisco Public Utilities Commission recently completed a phased development process for Green Infrastructure (GI) Typical Details and Specifications for the City of San Francisco. The typical details and specifications were developed to be robust yet flexible to support public and private sector design teams in developing construction-level drawings for GI projects in separate sewer and combined sewer areas, and on private lands or in the public realm. They are tailored to address San Francisco-specific design conditions – such as extreme density, rigorous ADA requirements, and narrow, steep streets – while remaining flexible enough to be broadly applicable to most project conditions. The development of the GI typical details harnessed the experiences from a multi-disciplinary team, and included inter-agency coordination to help inform and resolve existing City codes and policies. The typical details and specifications have been in use for nearly three years and have allowed for a collection of observed ‘lessons learned’ and ‘successes’ that will be helpful to other jurisdictions embarking on this process.
The development process was multidisciplinary and involved work across numerous city agencies. Details and specifications were developed by a diverse team of civil and structural engineers, landscape architects, construction managers and planners with an eye toward clear communication, design flexibility, facility performance, constructability, and maintainability. The development process included City inter-agency workshops and agency peer reviews, which provided the City with a forum to resolve gaps and conflicts within the codes and requirements of San Francisco’s many city agencies.
Each suite of details (e.g., roadside bioretention planters, permeable pavement) includes designer notes and guidelines that provide the user with design tools to properly adapt drawings to address site-specific conditions and performance goals. The comprehensive set of typical details include a wide range of configurations for permeable paving, bioretention facilities, subsurface infiltration, and a breadth of components that act as a ‘kit of parts’ to customize the GI based on site considerations.
Accompanying specifications were also developed for permeable unit pavers, pervious concrete, porous asphalt, and bioretention soil media. These specifications are the culmination of a series of workshops and collaboration with local suppliers, local testing laboratories, industry representatives, and City staff with a goal of producing high quality installations in the City while providing allowances for innovation. Infiltration testing methods and several other guidance documents were also developed to support design teams in San Francisco.
This presentation will focus on the development process, overview of the GI typical detail framework, lessons learned during the development process, and observed implementation challenges/successes during the first three years of public release and use by the development community. Specific topics will include the approach to inter-agency coordination and workshops, feedback loops, why “typical” instead of “standard”, coordination with material suppliers and industry representatives, and key GI design and construction considerations.
Ken Kortkamp acts as the stormwater program manager at the San Francisco Public Utilities Commission for the City of San Francisco. Ken is a civil and water resource engineer with over 20 years of private sector and public sector experience focusing in sustainable site development, green infrastructure design, and policy development. He oversees implementation of stormwater management on projects subject to the Stormwater Management Ordinance and coordinates development agreement for all redevelopment areas. He collaborates with city agencies to shape city-wide green infrastructure policies; from stormwater BMPs, living roofs, permeable paving, and non-potable reuse.
Alice Lancaster is a civil engineer at Herrera in Seattle Washington, offering specialized expertise in innovative stormwater management. For 18 years, she has worked with western Washington jurisdictions to develop green infrastructure (GI) policy, design guidance documents, and engineering standards that reflect the latest science and engineering advances. As a senior designer, Alice has developed basin-wide GI retrofit plans and GI design packages for private and public projects, including complex right-of-way retrofits. She enjoys collaborating with jurisdictions outside of the Pacific Northwest to share ideas and lessons learned.