Stormwater Detention with an Integrated Pump Station

As housing demand continues to grow throughout the Bay Area, developers must maximize every square foot of usable land while still meeting stormwater management requirements. At The Orchard townhomes in Danville, California, every inch mattered as Trumark Homes worked to deliver 124 new residences.

To preserve precious surface area for homes and amenities, the project’s stormwater detention system needed to move underground. At the same time, the development still had to satisfy Low Impact Development (LID) and Best Management Practice (BMP) requirements for stormwater treatment.

The result called for a space-efficient solution that kept critical water management infrastructure out of sight while maximizing the property’s developable area.

With developable land at a premium, a traditional above-ground detention basin would have consumed valuable real estate that could otherwise be used for housing. The project team needed an underground detention system to squeeze along the edge of the property within a narrow construction corridor.

Meeting LID and BMP requirements added another layer of complexity. Stormwater collected within the detention system needed to be moved to an above-ground bioretention basin sitting atop the StormVault for treatment, but there wasn’t enough room for a conventional pump station with a separate wet well and valve vault.

Accommodating both detention and how to move the stormwater without sacrificing additional buildable space presented a design challenge.

Jensen Infrastructure supplied a 240’ long, single-cell precast concrete StormVault detention system that provided nearly 20,000 cubic feet of underground storage while fitting along the edge of the property. Measuring approximately 12’ high and just 7’ wide, the H-20 rated system maximized developable land without compromising stormwater capacity.

To address the project’s LID and BMP requirements, the StormVault was manufactured with an integrated pump station located within the center module. Capable of pumping 247 gallons per minute, the system moves stormwater directly to the bioretention basin above for treatment.

By integrating the pump station into the detention structure, the project eliminated the need for a separate wet well and valve vault. The space-saving design created a more efficient stormwater system while preserving valuable surface area for additional homes and community amenities.

Need to fit underground detention in a tight space? Contact Jensen Infrastructure today.