The city of Santa Monica won the 2023 Helen Putnam Award for Excellence in the Public Works category. For more information about the award program, visit www.helenputnam.org.

Like many communities, Santa Monica has adopted new water supply management strategies to reduce the effects of climate change. California’s higher-than-average temperatures, heat waves, devastating wildfires, and historic droughts have tested the reliability and availability of water supplies — particularly in cities that rely on imported water.

“For decades, the city of Santa Monica has been chipping away at water self-sufficiency,” Mayor Gleam Davis said. “Water self-sufficiency is an ambitious goal that is achieved through a diversified water program where we capture and treat as much water as we possibly can locally.”

As part of its updated Sustainable Water Master Plan, the city opened a water purification facility in 2022 to create a diverse, sustainable, and drought-resilient local water supply. “By importing less water from the Colorado River and Delta, Santa Monica will be more resilient as water scarcity in the region only worsens,” Davis said.

The city’s efforts also address depletion and quality issues in the local groundwater aquifer, reduce stormwater pollution in Santa Monica Bay, lessen the city’s energy footprint, protect its water supply against natural disasters, and maintain affordability for consumers.

Investing in climate resiliency

One notable part of this plan is a $200 million Sustainable Water Supply Program that leverages alternative water supplies. This includes stormwater, dry weather urban runoff, impaired groundwater, and municipal wastewater, all of which can provide a diverse, sustainable, and drought-resilient local water supply. 

The program aims to increase local water supplies from 60-70% to roughly 90% by summer 2024. This would reduce the city’s reliance on imported water supplies from the oversubscribed State Water Project and the Colorado River. Key to this plan is the $96 million Sustainable Water Infrastructure Project (SWIP), a first-of-its-kind water recycling and potable reuse project with three elements:

• A 1.5 million gallon stormwater harvesting tank.
• A 1 million gallon per day advanced water treatment facility.
• Upgrades to an existing runoff recycling facility.  

“Protecting our future is what SWIP is all about,” Davis said. “The project will actively combat the effects of climate change on our water supply and push Santa Monica closer to our one water future.”

The project can draw on stormwater, urban runoff, brackish groundwater, and municipal wastewater during dry periods to produce highly purified water that recharges local groundwater aquifers.

Generous funding support from various sources made the project possible, including a revolving loan from the state, as well as state and regional grant dollars. “Projects of this size, scope, and complexity take partnership,” Public Works Director Rick Valte said. “We are thankful for our funding partners to make this innovative project a reality.” 

Leading the way in sustainable innovation

The Sustainable Water Infrastructure Project is in a highly urbanized area but is completely underground to minimize its impact on the community. The facility uses a multi-barrier purification process that includes biological treatment and multiple filtration steps using ultrafiltration, cartridge filtration, and reverse osmosis. Water is then disinfected with ultraviolet light, advanced oxidation, and chlorine. The result is safe, high-quality purified water that exceeds federal and state drinking water standards.

Santa Monica collaborated with several state agencies, including two divisions of the California State Water Resources Control Board, to implement the project and advance the needed regulatory framework. The project established treatment requirements for directly injecting treated stormwater/urban runoff into groundwater aquifers, as opposed to using vast amounts of land to slowly percolate the untreated stormwater back into the ground.

The project was recognized on the global stage at the 2024 Global Water Awards. It received the Distinction Award in the Water Reuse Project of the Year category — second only to the overall winner, the United Arab Emirates.

“We are very proud to deliver several first-of-its-kind innovations in the state of California,” Valte said. These first-of-their-kind innovations include:

• The first stormwater harvesting project to directly inject treated runoff/stormwater for potable reuse in California.
• The first membrane bioreactor and cartridge filter treatment system granted pathogen removal credits in potable reuse applications in California.
• A completely underground facility designed to treat a blend of wastewater/stormwater and meet groundwater recharge standards all within one facility. 

These innovations make it easier to advance stormwater capture and reuse and can serve as a roadmap for other water utilities. The facility can produce up to 1,650 acre-feet per year of purified water — roughly 10% of the city’s water supply.

City officials estimate the facility diverts over 40 million gallons of pollution away from Santa Monica Bay each year. It also improves the city’s ability to maintain affordable water rates. The city’s local water supply historically costs 30% less than imported water supplies. 

“The SWIP is a model of innovation for other cities and municipalities as it brings multiple sources of water together, including stormwater, dry weather urban runoff, brackish groundwater, and municipal wastewater, to provide a sustainable and drought-resilient local water supply,” said David Nahai, Los Angeles Regional Water Quality Control board vice chair.

As water and climate resiliency become increasingly important, Santa Monica is committed to maximizing its local water resources, protecting the environment, and reducing its reliance on imported water. Projects like the Sustainable Water Infrastructure Project are essential to turning that commitment into a reality.

City officials are already planning for new ways to achieve 99% water self-sufficiency. 

Sunny Wang is the water resources manager for the city of Santa Monica. He can be reached at  sunny.wang@santamonica.gov.