“Bioretention” is a broad term. “Rain garden” is still broader. Indexed here are projects with relatively small depressed areas designed to retain water for a short time in order to slow down and reduce storm runoff peaks, as well as reduce pollution. A common slogan is “slow it, spread it, sink it.”

Keeping a runoff pattern reasonably similar to what existed before development generally requires some 3-5% of the project area, as well as excavation and plumbing: Raised drains to prevent flooding, underdrains to carry heavy flows to storm drains, and layers of crushed rock and highly permeable soil.

Not indexed here are (a) larger ponds or (b) projects with bioretention areas that are a relatively small part of a more complex system. Large parking areas, for example, often have both elongated swales and small corner bioretention areas.

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Alameda County Juvenile Justice Center
bioretention area surrounded by McDonald's drive-though lanes
Berkeley: McDonald’s
Albany School District’s Cougar Field
Arbor and plantings in runoff basin at JC Penney store, AntiochPenney’s, Antioch; Lowes, Concord
Swale at Rose Garden shopping center, Danville
Rose Garden
shopping center

El Cerrito Sidewalk Rain Gardens

El Cerrito City Hall
Rain Garden and Street Trees that filer runoff, Doyle Hollis Park
Emeryville: Doyle-Hollis Park
Basin retains runoff on slope at Belmont Terrace, Martinez
Martinez: Slowing runoff on a slope

Oakley City Hall
Parking lot runoff flows to colorful landscaping.
Pittsburg City Hall and Richard E. Arnason Justice Center

Pleasant Hill: Hidden Creek
Rain garden colors harmonize with building color scheme
San Pablo: Shopping area at El Portal Drive and San Pablo Avenue

UC Berkeley: Grinnell Glade
Large rain garden planted with bands of differently-hued vegetation
Walnut Creek: AAA and Varian Headquarters
Rain Garden at Walnut Creek Library
Walnut Creek Downtown Public Library

Walnut Creek: North Creek Church