City of Alhambra Green Street Feasibility Study

Herrera led the stormwater management and landscape architecture design for a Green Street Demonstration Project on Main Street in the City of Alhambra, California. The project includes a series of bioretention cells along the southern street frontage and in the center medians totaling nearly 23,000 square feet of treatment area, as well as reconfigured parking and roadway striping, to provide water quality treatment and infiltration to 21 acres of contributing development area while enhancing the streetscape and reducing heat island effects. The stormwater management design also includes infiltrating runoff from an additional 16 acres of tributary area through a system of 7 drywells. The project will provide multiple benefits to the neighborhood and surrounding environment including beautifying the street, reducing stormwater runoff volumes and pollutant loads, reducing pavement area, improving pedestrian facilities, enhancing open space, enhancing native plantings and habitat, as well as a demonstrating to the public of the benefits of green infrastructure. Herrera also developed a project monitoring plan to evaluate and verify BMP performance, and both capital and life-cycle costs to build, operate, and maintain the facilities throughout their lifetime. The project design was used as the foundation for a feasibility study, which was submitted for funding in 2022 under LA County’s Safe Clean Water program.

All Photos Courtesy of Toole Design.