Three street intersections along Central Avenue will be getting a makeover to render them better for the environment. The intersections will incorporate bioretention facilities, which are special soil and vegetation features that help filter out harmful chemicals from stormwater runoff before the stormwater flows into the Bay. 

On July 5, after a decade of planning and funding efforts, the city council gave the go-ahead to begin work in 2024 on the “Central Avenue Safety Improvement Project.” 

The city’s approval comes after the U.S. Environmental Protection Agency (EPA) awarded $1.47 million to the city for the project. The EPA funds, along with a matching amount from the city, will allow the city to incorporate the bioretention facilities. “This EPA water quality grant represents the last incoming monies for this corridor improvement project, which now totals $22 million,” said Gail Payne, Project Manager and Senior Transportation Planner for the city.

The project area runs on Central Avenue from the intersection at Encinal Avenue to the intersection at Pacific Avenue. 

Four intersections in the project area were initially planned for reconfiguration as a roundabout with bioretention facilities, but only three will receive the upgrade. The three reconfigured intersections along Central will be at Pacific Avenue, Taylor Avenue, and Ballena Boulevard. The intersection at Sherman/Central/Encinal lacks funding for a roundabout and bioretention areas, according to Payne, and will instead receive the same types of upgrades as other intersections. 

Intersection of Central Ave. and Ballena Blvd.

Among other features in the rest of the project, traffic lanes on Central Avenue will be reduced from four to three with a center turn lane and a two‐way separated bikeway will be constructed adjacent to schools.

Bioretention facilities “are landscaped depressions that treat on-site stormwater discharge from impervious surfaces such as roofs, driveways, sidewalks, parking lots and compacted lawns,” explains the EPA on its website. “They are used to collect stormwater and filter it through a mixture of soil, sand and/or gravel.”

Approximately 15 bioretention units are proposed in the curb bulb-outs located around the three new roundabouts, with footprints ranging from 25 to 2,300 square feet. These nature-based units are designed to filter runoff from 70 acres of paved, or impervious, surfaces along the roadway.

The bioretention facilities will also serve as trash capture devices performing the same function as the hundreds of screen baskets already installed in street storm drains around the city.  Alameda’s bioretention facility funding is one of 24 Bay Area clean water projects totaling over $50 million recently funded by the Biden Administration.

Intersection of Central Ave., Taylor Ave., and Third St.

Intersection of Pacific Ave., Central Ave., and Main St.

Bioretention facility on Orion Street at Alameda Point.

Originally published in the Alameda Post.