Creating a Sustainable Water Resource to Combat California Droughts

WSP USA is part of a design-build team constructing a facility that will recharge a natural groundwater aquifer and boost the region’s reserve water supply.

Work is under way on the Sterling Natural Resource Center (SNRC) in the City of Highland, California, a state-of-the-art facility that will provide a sustainable new water supply for residents in the San Bernardino region.

When completed in late 2021, the SNRC will be capable of treating up to 10 million gallons of water every day, recharging the local Bunker Hill Groundwater Basin and significantly boosting the region's water independence by optimizing natural resources and turning wastewater into a previously untapped, sustainable water source.

WSP USA is a sub-consultant to the prime design consultant Arcadis for the project, working on behalf of the East Valley Water District. The project team is led by Balfour Beatty and also includes Ruhnau Clarke Architects, Trussell Technologies and Inframark.

“Our aquifers are thirsty,” said Zack Isnasious, WSP project manager. “The Bunker Hill Basin is at historic lows, yet (East Valley Water District Board President) Chris Carrillo said that it still allows six million gallons of water to leave this region every single day to go to another place where they use it. The Sterling Natural Resource Center is going to stop that.”

The SNRC is being constructed on 14-acres, which includes a treatment facility on the eastern side of the property, while an administration center is being constructed on the western section of the property. The administration center will include a multipurpose hall to host local events, a park, water bodies and an amphitheater.

“The new facility is going to create some fantastic opportunities for the surrounding community, with space that can be used for education and training,” Isnasious said. “The property will also enhance the natural beauty of the neighborhood and establish an important new habitat for the endangered Santa Ana sucker fish,” Isnasious said.

The Santa Ana sucker is a freshwater fish found in only a handful of Southern California streams. It is listed as endangered by the International Union for Conservation of Nature.

Invaluable Resource

The need for facilities like the SNRC became abundantly clear in 2015, while California was in the midst of a prolonged six-year drought—one of the most intense and dangerous in state history—that made water conservation an essential part of life for residents.

When completed, the $180 million facility will turn wastewater into a potable resource, while also storing a significant water supply that will provide the region with an invaluable reserve when facing severe and sustained drought conditions.

SNRC will be able to first treat eight million gallons of water each day when it opens, and eventually expand to a capacity of 10 million gallons a day.

“The facility will replenish the Bunker Hill Basin with recycled water, and will be able to store hundreds of millions of gallons of water,” Isnasious said. “This is going to be transformative to the natural health and independent sustainability of this region.”

The facility’s reach will include three cities—San Bernardino, Highland, and Redlands—as well as other areas in the County of San Bernardino.

One of the biggest challenges to the plan has been coordination of efforts between multiple entities involved, as well as securing the necessary permits for the major flood control channels and waterways.

One of the innovations WSP developed for the project should improve the sewer connection for the system. WSP is diverting sewer from the existing sewer collection system to the new 48-inch major trunk sewer over 1.5 miles to meet the operation phasing of the treatment plant and to ensure proper system start up.



The Sterling Natural Resource Center will turn wastewater into a potable resource while also providing the region with an invaluable water supply reserve.

Serving as a Model

Though SNRC will bring significant improvements to the local water supply, the effort is literally a drop in the bucket compared to what the Environmental Protection Agency (EPA) believes will be needed to protect and maintain water supplies over the long term estimating that drinking water and wastewater infrastructure needs expansion and upgrades exceeding $700 billion.

“U.S. population growth is straining many of the country's wastewater treatment plants, which is a critical public health concern that needs to be addressed sooner rather than later,” Isnasious said. “But the success of the SNRC facility could serve as a model for how other communities across the country could protect and expand their own water supplies for future generations.”

The American Society of Civil Engineers (ASCE) reported that more than a million miles of drinking water pipes installed in the first half of the 20th century are still being used and have exceeded their useful life. These aged pipes have been responsible for most of an estimated 240,000 water main breaks that occur every year, wasting about two trillion gallons of drinkable water. ASCE said it will take an investment approaching $300 billion over the next 20 years to adequately address these problems.

“Replacing these outdated pipes with new and more efficient systems could create opportunities for these communities to alleviate many of their water and wastewater concerns and improve the quality of life for citizens who depend upon that infrastructure,” Isnasious said.

Active Engagement

One of the goals of the SNRC project has been to maintain active engagement and participation with residents who will benefit from the facility, ensuring that there is an understanding of why it is important, answer questions and address concerns, and prepare citizens for what they can expect to occur during installation and construction.

“The community has been engaged from the first day we started the job,” Isnasious said. “East Valley Water District created social media websites for community to provide suggestions and to watch live camera on the construction sites and provide feedback. They’ve also developed a fly-through video of the project rendering, to show the community how the constructed facility will look.”

He said construction of the aeriation basins and influent pump station began in late 2018, and currently the sewer collection system has been out for bid by specialized contractors.

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