Sustainable water infrastructure project addressing Santa Monica’s drought resilience

A California city known for its startup scene is on the cutting edge of water supply sustainability after completing an innovative infrastructure project late last year.

The City of Santa Monica’s Sustainable Water Infrastructure Project (SWIP) opened in November 2022 as a key part of its Sustainable Water Master Plan, which aims to improve the city’s water supply resilience in an era of ongoing drought.  

The SWIP uses a huge water tank to capture and treat stormwater. An underground, one-million gallons-per-day advanced water treatment facility processes wastewater, stormwater, dry-weather runoff and brackish groundwater for non-potable uses, such as landscape irrigation and toilet flushing. Furthermore, capturing stormwater keeps any potential contaminants – oil, paint and plastics – out of the ocean. (Pictured right, construction of the SWIP’s 1.5 million gallon stormwater harvesting tank.)

Eventually, when California regulations allow it, SWIP will be able to treat recycled water to local drinking water standards. Currently, the city relies on imported water for 30-40% of its drinking water. 

“A key component of the city’s One Water approach is to leverage alternative water supplies, such as stormwater harvesting and municipal wastewater, and technology innovations to bolster local water supplies and enhance drought resiliency,” said Sunny Wang, the city’s water resources manager.

The city expects the SWIP will someday produce enough drinking water to supply approximately 20% of the city’s population.

In capturing stormwater and runoff, the city anticipates SWIP will improve local water quality by diverting 100 million gallons of pollution annually away from the Santa Monica Bay. The city worked closely with the Regional Water Quality Control Board to establish regulations for stormwater treatment and groundwater recharge.

Located on Santa Monica’s Main Street, between the Civic Auditorium and courthouse, the SWIP looks like a parking lot adorned with planters from the surface street (pictured right). The planters mask air vents that emit filtered air from the treatment plant, eliminating any odors from being detected by passersby.

The project also included upgrading the Santa Monica Urban Runoff Recycling Facility, known as SMURRF, making it the state’s first project that directly injects treated stormwater into a groundwater basin, boosting local groundwater supply.

In all, the SWIP project cost $96 million. Funding came from different state and county sources, including:

•    $75 million from the State Water Resources Control Board through clean water state revolving funds, including $8.77 million through the Prop 1 Stormwater Grant
•    $19 million from the Metropolitan Water District of Southern California through its Local Resources Program
•    $7.5 million from the Los Angeles County Department of Public Works (through its Measure W’s Safe Clean Water Program)

“As water and climate resiliency become increasingly important topics for all of us, the City of Santa Monica is committed to maximizing its local water resources and reducing its reliance on imported water through projects such as SWIP,” Wang said. “The SWIP is a model of innovation as it brings multiple sources of water together, including stormwater, dry weather urban runoff, brackish groundwater, and municipal wastewater, to provide a sustainable local water supply.”