Monday, March 22, 2010

San Francisco Stormwater Management Ordinance

BOMA San Francisco Members:

We kindly request your feedback on the San Francisco Stormwater Management Ordinance that would amend the San Francisco Public Works Code to require the development and maintenance of stormwater management controls for specified activities that disturb 5,000 square fee or more of the ground surface including, but not limited to, the construction, modification, conversion, or alteration of any building or structure and associated grading, filling, excavation, change in the existing topography, and the addition or replacement of impervious surface.  The measure will also create a Stormwater Management Plan to verify that no additional run-off will be created by a new development/project, and that any such new run-off is being properly treated or mitigated in an approved fashion.

You can download the ordinance, here. Please pay attention to page 3, Section 147.1 (c) and page 5, Section 147.2.  The measure is scheduled to be considered at the Board of Supervisors on Tuesday, March 30th; email Ken Cleaveland, BOMA San Francisco's Director of Government and Public Affairs at with any comments you may have.

What are Stormwater Design Guidelines?

The Port of San Francisco (Port) and the San Francisco Public Utilities Commission (SFPUC) are developing the San Francisco Stormwater Design Guidelines (“Design Guidelines”).  The Design Guidelines will improve San Francisco’s environment by reducing pollution in stormwater runoff in areas of new development and redevelopment. The Design Guidelines will be applied in areas of San Francisco served by separate storm sewers that discharge directly to local lakes or San Francisco Bay.  Given current trends in development, at this time mostly Bay waterfront parcels will be affected.

Please click here to review the Stormwater Design Guidelines.

What is stormwater runoff and why is it a concern?

Stormwater runoff is rainwater that flows over the land surface and through collection pipes.  In vegetated areas such as forests, fields and wetlands, rainwater seeps slowly into the ground, limiting runoff.  However, when rain falls on paved concrete and other hard (impervious) surfaces such as those found in most of San Francisco, it runs off quickly and is conveyed by pipes and other drainage features.  Though starting as relatively pure rainwater, stormwater runoff collects pollutants as it flows over impervious surfaces.  For example, runoff from parking lots picks up oil and grease from leaking engines, copper from worn brake linings, and zinc from tires. Although most runoff in San Francisco flows into the combined sewer system and receives treatment at the city’s two sewage treatment plants, there are a few areas in the city that discharge directly into  San Francisco Bay or other surface water such as Lake Merced without receiving any treatment.  These polluted stormwater flows can be detrimental to aquatic and other life.  The Design Guidelines will help improve San Francisco’s environment by reducing pollution in water that runs to the bay or other waters from newly constructed facilities.

How can San Francisco help reduce the detrimental impacts of stormwater runoff? 

One way to help reduce the detrimental impacts of stormwater runoff is by changing the way we approach new construction.  New development and redevelopment projects can be designed to minimize pollutant exposure within the project area.  Through careful pre-construction planning and designing, new development and redevelopment projects can be built to:

  • Minimize impervious surfaces, which would allow more rainfall to soak into the ground
  • Reduce the volume and intensity of storm water runoff, which would reduce flows that end up in the receiving waters 
  • Convey and treat storm water runoff using landscape features and other “green” systems  to provide treatment to the pollutants in the runoff

Studies performed around the world show that proactive site planning and design is the most cost-effective approach for reducing stormwater pollution.

What is San Francisco doing to address stormwater impacts associated with new development and redevelopment projects?

As the owners and operators of San Francisco’s storm drain systems, the Port and the SFPUC have teamed to develop the San Francisco Stormwater Design Guidelines.  The  Design Guidelines will apply to new development and redevelopment in areas of San Francisco served by separate storm sewers (e.g., storm sewers that discharge directly to receiving waters).   The Port and the SFPUC invite you to participate in the development of the Design Guidelines.

Is San Francisco required to develop Stormwater Design Guidelines?

Yes - a Clean Water Act discharge permit administered by the State Water Resources Control Board requires local agencies to develop programs for the control of stormwater runoff for the life of a project (“post-construction control” of stormwater).  The Design Guidelines will comply with the mandate of this permit, while at the same time providing a vehicle through which planners, designers, engineers and developers can work together toward a more sustainable city.

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