Stormwater Management & Water Quality

Interstate 880/5th Avenue Overhead Seismic Retrofit Project | City of Oakland, California

Existing Project Site
Existing Project Site
Caltrans District 4
Project Description:
Caltrans initiated the Interstate 880/5th Avenue Overhead Seismic Retrofit Project, which includes the complete retrofit and replacement of an existing Interstate 880 freeway structure over Lake Merritt Channel in the City of Oakland. The new structure would meet current seismic standards. The San Francisco Bay Regional Water Quality Control Board issued 401 Water Quality Certification to Caltrans for the project on June 30, 2005, and the certification required Caltrans to mitigate for the project's anticipated post-construction stormwater impacts through provision of an alternative compliance, off-site treatment project in partnership with the City of Oakland.

A standard Austin Vault Sand Filter (AVSF) includes a sedimentation basin and a sand media filter placed adjacent to each other within a below-grade vault. For this project, WRECO is assisting Caltrans in designing non-standard, aboveground AVSFs to fit in the project site, which is constrained by freeway bents. The innovative designs have sides of equal length and feature nested chambers, with the sand media filter chamber set in the center of the sedimentation chamber. Furthermore, the aboveground design eases maintenance access and reduces construction costs.
Key Tasks:
Water Quality Support Services, Stormwater Treatment BMPs Design of the Austin Vault Sand Filter and Biofiltration Swale, Contract Change Orders and Construction Support
Rendering of the AVSF
Rendering of the AVSF
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