EL CERRITO -- An innovative project installed by the city to cleanse storm water naturally before it reaches San Francisco Bay is serving as an inspiration for a similar, but larger project planned for El Cerrito and six other East Bay cities.

Contractors will rip up pavement at a string of sites along San Pablo Avenue through El Cerrito, San Pablo, Richmond, Albany, Berkeley, Emeryville and Oakland, and install 3-foot-deep landscaping beds, as much as 100 feet in length and six to seven feet wide, between the sidewalk and the street.

The beds contain special soil mixes and drought-resistant plants to absorb toxins from water that flows off rooftops, sidewalks and streets.

Rain garden and explanatory panel on San Pablo Avenue in El Cerrito.
Rain garden and explanatory panel on San Pablo Avenue in El Cerrito.

The water percolates through special purifying soil mixes and gravel and into perforated pipes at the base of the beds and from there is released into storm drains that lead to the Bay, said Josh Brandt, project manager for the sponsoring agency, the Oakland-based San Francisco Estuary Project.

"We have to pull up the pavement and dig below the gutter lines, allowing storm water to get in and soak in," Brandt said.

The water treated through the beds will reduce but not eliminate the flow of untreated water that cascades into the storm drains from the East Bay hills, according to Yvettah Ortiz, El Cerrito's interim public works director.

In 2010, El Cerrito created what has become the pilot project for the latest initiative by installing the water cleansing beds, which it refers to as "rain gardens," near the intersections of San Pablo Avenue and Madison Avenue and San Pablo and Eureka Street.

"(The Estuary Project) saw the success of what El Cerrito has done and reached out to other agencies interested in similar types of (systems)," Ortiz said.

The new El Cerrito beds will be placed at the intersections of San Pablo and Moeser Lane and San Pablo and Stockton Avenue.

Rain garden installation on San Pablo Avenue at Eureka Avenue in El Cerrito. Similar installations will be coming to neighboring cities under a program to
Rain garden installation on San Pablo Avenue at Eureka Avenue in El Cerrito. Similar installations will be coming to neighboring cities under a program to treat storm runoff before it enters the Bay.

Construction is expected to begin in early fall, starting in Oakland and Emeryville and then moving north, Ortiz said.

The project is expected to cost about $4 million, with about half of that coming in Caltrans mitigation funding from the Bay Bridge eastern span construction project, Brandt said.

"Caltrans couldn't treat the storm water on the bridge on-site, so it had to find an alternative off-site," Brandt said. "It's a nice solution."

The project is also receiving grants from the federal Environmental Protection Agency and the state Department of Water Resources.

"After a two-year funded period to allow the plants to become established, all the sites go back to the cities for long-term maintenance and care," Brandt said.

El Cerrito is taking other steps to reduce pollution from rain water runoff including intercepting garbage before it flows into the storm drains, Ortiz said.

"One thing we are doing to meet Regional Water Quality Control Board requirements is to install traps inside the storm drain inlets to capture trash before it goes into the drains," she said.

The city is also about to begin another rain garden project along the Ohlone Greenway south of Fairmount Avenue. Water that flows into a storm drain on Fairmount Avenue will be directed into a rain garden set in the natural landscape.

"It will be a natural setting, rather than a concrete box," Ortiz said.