Expo Rail Maintenance Facility, Santa Monica, CA


Expo Rail Maintenance Facility, Santa Monica, CA


Kiewit Construction for the City of Santa Monica


Stormwater Harvesting


April 2016


When the City of Santa Monica began planning a nearly 80,000 square foot, state of the art Operations and Light Rail Vehicle Maintenance Facility for the L.A. Metro, they needed to reduce stormwater runoff on the property by California ordinance. However, they also wanted to collect the stormwater for non-potable reuse, which along with other sustainability initiatives, led the City to pursue LEED Gold certification for the project. This would be achieved by installing solar thermal panels, providing bike racks and preferred parking for fuel efficient and carpool vehicles, utilizing natural daylight in the facility, and installing a stormwater harvesting system, among other efforts.

Stormwater Harvesting
City of Santa Monica


The City of Santa Monica needed to include a significant stormwater detention system to reduce stormwater run-off for the facility in their construction plans, and as a LEED Gold project, the team also wanted to find a way to use the detained stormwater for non-potable application at the facility.


Wahaso provided a system design to treat harvested water to California Title 22 standards so that it could be safely used to irrigate the landscaping and to provide water to wash the train cars. Wahaso’s supply partner, Oldcastle Precast, provided the 800,000-gallon Storm Capture cistern and the NSBB pre-filtration for the collected rainwater and stormwater. The system uses OptiRTC technology to monitor weather events and manage cistern levels so that detention capacity is always available for a storm event, while avoiding the unnecessary discharge of rainwater.


With an estimated demand of 5,500 gallons of water per day, the system is expected to save 1.2 to 1.6 million gallons of water per year while greatly reducing stormwater run-off from the entire property. The harvested water helps to reduce potable water use by over 40% at the facility and provides over 50% of the municipal water that would have been needed for landscape irrigation.

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