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Big Blue Bus Upgrade

Santa Monica, California

Stormwater Treatment


City of Santa Monica


KPFF Consulting Engineers Los Angeles, CA


Blois Construction Inc. Oxnard, CA



Technical Description:

  • (2) Stormwater Management StormFilters
  • (2) CON/SPAN Detention Systems

Facilities and parking area upgrade incorporates high volume detention and treatment

The Big Blue Bus provides bus service to the City of Santa Monica, CA. Recently it upgraded its facilities to include a parking expansion of the existing 6.5-acre bus terminal. The increase in impervious area created a need for a stormwater management solution that would meet the City of Santa Monica stormwater requirements.

There were many site challenges that needed to be overcome when it came to the detention system. Requirements stated that no water could leave the site. Due to space constraints, a below-grade solution was needed. The ability to accept adequate loading had to be considered, as the parking lot would be used for large buses and fire trucks. The detention system also had to be below 15-ft due to possible contaminated soils.

The project engineers chose a CON/SPAN concrete detention system from Contech Engineered Solutions. The precast arch unit would be installed on cast-in-place strip footings with a paved invert, which is a thin nonstructural section of concrete that provides a closed bottom for the vault. This allowed the system to be used for detention. Providing continuous footing would also ensure no differential settlement.

The City of Santa Monica required that EPA treatment benchmarks for metals, solids, trash and debris, and oils and grease in stormwater runoff be met for this project. In order to achieve this level of treatment, the Stormwater Management StormFilter system — another product of Contech — was chosen.

Technical Description:

  • (2) Stormwater Management StormFilters
  • (2) CON/SPAN Detention Systems

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