San Francisco Waldorf High School

The San Francisco Waldorf High School is an independent school located in the West Portal neighborhood. Coffman provided civil engineering services for the phase I expansion which included a 10,000-sf gym, courtyard, driveway entrance, parking lot reconfiguration, and utilities. Specific design work included: site planning and layout, erosion and sediment control, demolition, earthwork, grading, drainage, stormwater management and treatment measures to meet the City requirements, stormwater control plan, ADA paths of travel, public water main upgrade/replacement, utilities, and associated details to support the bidding of the project. Permit coordination was also provided for new fire service and public water main upgrade with the San Francisco Public Utilities Commission (SFPUC) Water Department.

A unique aspect of the project was meeting stormwater requirements for the new gym and parking lot improvements on a steep slope. The city code didn’t allow for stormwater infiltration systems to be installed with 100 feet of the start of a 15% or greater slope and eliminated all possible locations for a stormwater infiltration system.

However, after reviewing the geotechnical report, our civil engineers saw that the site soils were sandy and requested that the geotechnical engineer do a perc test to determine if the steep slope setback could be reduced. With the results of the perc test, the geotechnical engineer determined that the slope setback could be reduced to 50 feet making a stormwater infiltration system feasible. This resulted in the installation of a smaller detention system and cost savings for the owner.