Via Blue and Green Cities, an article on Los Angeles’ green infrastructure:

In California, the Southern California Water Replenishment District estimates that in a single year alone, Los Angeles loses 58 trillion gallons of water to the ocean. To collect some of this excess water off the city’s impervious surfaces, the city is designing and constructing ‘green streets’, which are streets that reduce, treat, and capture stormwater runoff close to its source. One green street being constructed is the Laurel Canyon Boulevard Green Street Project which will see a series of vegetated infiltration swales and dry wells along the northeast side of Laurel Canyon Boulevard. During storm events, these swales and dry wells will capture and treat stormwater runoff from an approximate 123-acre drainage area and infiltrate it into the San Fernando Groundwater Basin. During a normal year, the project has the potential to replenish 13 million gallons of rainwater annually into underground aquifers.