El Cerrito Green Streets Rain Gardens
Water Quality Improvement
The El Cerrito Green Streets Pilot Project officially concluded on November 30, 2012. Click on these links to view or download the Final Project Report, the Final Water Quality Monitoring Report, and the As-Built Construction Documents.
This successful project retrofitted the conventional public right-of-way (street edge and sidewalk area) with a series of stormwater treatment cells (aka rain gardens) at two sites along San Pablo Avenue in El Cerrito, CA.The 750 linear feet of rain gardens (19 individual treatment cells in all) were constructed in 2010, on the east side of the 10200 & 11000 blocks of San Pablo Avenue. Curb cuts direct flows from the adjacent street and sidewalk areas into depressed bioretention cells. The cells are planted with native drought-tolerant plant species in a bed of amended soils.The soils, plants, and microbial organisms within the rain gardens slow runoff and naturally filter pollutants before the stormwater is discharged into Baxter and Cerrito Creeks and eventually to the San Francisco Bay.
The purpose of this pilot project not only was to directly improve local water quality, but also to promote public awareness of stormwater pollution, and expand local governments’ existing stormwater management toolbox to include green infrastructure approaches. Therefore, the project also included performance monitoring, community outreach, and technology transfer to local governments.
Post-construction wet weather sampling of stormwater influent and effluent was conducted during four storm events over the 2011-12 water year. These samples were analyzed to quantify the pollutant removal efficiencies of the rain gardens. Monitoring results indicate the gardens are successful in reducing concentrations for a variety of urban runoff pollutants such as PCBs, pyrethroids, suspended sediments, methyl mercury, and copper.
Outreach activities occurred throughout the project’s planning, construction and monitoring phases. To ensure the long-term performance of the rain gardens, all appropriate city staff were trained in best maintenance practices. Many of the outreach materials developed for the project, such as video podcasts, interpretive signage at the sites, and educational pamphlets will continue to provide meaningful information about the art and science of green streets.
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