Doing More with Less: Stormwater Runoff is Turned into a Design Opportunity

A series of case studies illustrating cost-effective, sustainable design solutions that save materials, energy and water.

Cypress College is reshaping its campus to better support students and faculty. A new Science, Engineering and Math (SEM) facility created an opportunity to reshape the grounds around the facility, but the project required a system to treat stormwater runoff, which often means expensive and/or unsightly concrete biofiltration vaults or random and disconnected bioretention basins with imported soil media and subdrain systems.

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The stormwater treatment strategy was integrated into the site plan and larger goals for the facility.

LPA’s integrated team developed a water-quality treatment system to consolidate stormwater runoff from the building into two large infiltration basins that were shaped to fit naturally within the site, freeing space for a more cohesive landscape design and creating connections to the campus’s pedestrian flow.

The integrated design process started with alignment of the new building along existing pedestrian corridors to consolidate open space. Below the site, engineers discovered granular subsoils, which required the use of deep pile foundations to support the structure and provide seismic resiliency.

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Native plants were specifically chosen for the site and soil.

But the same granular subsoils provided the civil engineering team with an opportunity to design a stormwater treatment system that allows water to infiltrate directly into the existing soils, eliminating the need for unsightly concrete vaults or more expensive bioretention basins with imported soil media. Infiltration basins are not a new treatment system, but LPA’s integrated teams worked closely to design this more traditional water-quality system so that it blended seamlessly into the landscape design to provide both form and function.

“Bioretention basins don’t always look great after construction,” says LPA civil engineering Design Director Andrew Christiansen. “They often stick out like a sore thumb and are easily identified on a site, due to sketchy construction and inconsistent, poorly executed plantings.”

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The design added form and function to the site.

To design the water-quality system, LPA’s integrated team managed the flow path for every drop of water from the time it hits the roof until it infiltrates into the soil at the basins. Consolidation of runoff into two large basins maximized efficiency and minimized excavation and earthwork, particularly the need to import select soils and gravel. The larger basins facilitated a more consistent plant layout across the site and eliminated interruptions to the landscape scheme often caused by multiple, smaller bioretention basins or concrete vaults.

The design developed by LPA’s integrated team successfully blended a traditional water-quality solution into the site design to create a beautiful setting for outdoor learning programs as well as an enhanced student experience on the growing campus.