San Francisco's Sewer System Improvement Program aims to build new infrastructure that can infiltrate more water down into the ground, thus shaving off the peak flow. SSIP has plans for the streets east of the Panhandle. On Saturday morning, Raphael Garcia of the SF PUC led about 40 residents, as well as other employees from PUC and SF MTA, on a walking tour of Oak and Fell Streets, starting at the east end of the Panhandle and extending three blocks to Scott Street. At Baker and Oak, just in front of Mt. Zion Baptist Church, a rain garden will be installed in the curbside lane on Oak starting at the northwest corner of the intersection and extending about 16 feet long. The plants in the rain garden will be maintained by the PUC and will be planted with colorful California native plants, chosen for medium stature (not above hip level) and for habitat for creatures like the tiger swallowtail and black phoebe.
Rather than installing rain gardens directly adjacent to the Panhandle Park, the south side of Oak Street was chosen as a site to optimize the effects and capture a greater flow of water. Other factors taken into consideration were the potential for shading, leaf debris, and impact on tree roots if the city were to implement rain gardens directly next to Panhandle Park. The material that goes beneath the new PUC rain gardens will not just be regular dirt; it'll be "engineered media" that can handle the "urban slobber" coming in with the water flowing from the city streets while supporting the mycorrhizal fungi that begins to filter and clean the water as it percolates down to our ground water, far below the surface.
Since there are expectations for extensive engineering changes to improve traffic safety at the intersection of Baker and Oak, SF MTA staff on the tour explained that bulbouts will be constructed on the park side of this intersection.
Construction of the rain gardens is expected to start in early summer 2014.
|Raphael Garcia of PUC speaks at the location of another planned rain garden|