As drought-plagued western states watch their water sources literally dry up, California is digging deeper to tap the most basic source of all: groundwater.

Amid a worsening drought scorching much of the western U.S., California’s numerous and varied potential drinking water sources are becoming unusable or, when purchased from Colorado or other districts, too costly. As reservoirs, rivers and washes dry out, state water resource administrators are boosting use of alternative supplies to ensure water keeps flowing.

California drought
PARCHED | The megadrought impacts every area of the state, California’s Dept. of Water Resources says. Record dry conditions, which include reduced snowmelt, now extend through much of the western U.S.

Groundwater is the “abandoned child of the water system because we have not been very meticulous in the way we gathered data or managed or protected it,” says Newsha Ajami, chief development officer for environmental research at Lawrence Berkeley Lab in Berkeley, Calif., and a longtime state drought expert.

But more reliance on groundwater is problematic for a variety of reasons.

Many groundwater wells—not monitored or managed until California enacted the Sustainable Groundwater Management Act in 2014—have simply been overdrawn.

Moreover, it was common practice during the 1940s and 1950s for industrial facilities, manufacturers and even dry-cleaners to dump chemicals and waste underground, leaving a legacy of pollution that renders some groundwater undrinkable.

Los Angeles is able only to consistently draw from 41 of 115 wells in the San Fernando Basin, a collection of regional underground aquifers that currently provide about 10% of city water supply. This has caused a 50% reduction in its historical groundwater supply. But the LA Dept. of Water and Power says the basin has the potential to provide as much as 21% of city water.

As a result, the department is working with federal and state officials, potentially responsible polluted site owners and a slew of engineering and construction firms on multiple remediation projects to return a more significant portion of groundwater supply to the drinking water system. Concentrated in the San Fernando Valley, these projects are using a combination of granular activated carbon tanks coupled with ultraviolet advanced oxidation when needed to clean up pollutants that have remained in the basins for decades.

Municipal Supply Wells with Contaminants at or above Safe Drinking Water Levels
The California Water Board says that hundreds of drinking water wells throughout the state have been contaminated. Not all can feasibly be remediated, says board member Sean Maguire. California now has a statewide effort underway to map all high- and medium-priority groundwater basins.

State Water Resources Control Board member Sean Maguire, a civil engineer and former consultant, says the department has been a “real leader” in transforming water that was formerly off limits for use into a future significant portion of the city water portfolio. 

The U.S. Environmental Protection Agency established four Superfund sites within the valley in the mid-1980s, and efforts to identify responsible parties and remediate the groundwater basin have continued since then. 

Some toxics, mainly detritus from manufacturing facilities that provided parts for aircraft, include a veritable alphabet soup of volatile organic compounds (VOCs), including trichloroethytlene, perchloroethylene, petroleum compounds and heavy metals.

Also present is 1,4 dioxane, often found in paint-stripping products, as well as hexavalent chromium, which is both naturally occurring and contained in some consumer and industrial products such as coatings and plastics. Many of these chemicals are in large enough quantities that the water is not safe to drink unless it is treated. 

Complex Sites

Efforts to clean up contaminated groundwater sites have been complicated by the discovery of additional VOCs as well as by changing geological conditions that have caused a plume of contaminants to spread to new areas. 

water remediation

TIGHT QUARTERS | One remediation project is squeezed into a city block in a residential North Hollywood neighborhood. The construction crew has had to make adjustments, such as storing materials offsite, to work efficiently onsite.

“People don’t realize these [groundwater] basins are so large across so many different geographical and jurisdictional boundaries,” Ajami says. “People use them for different purposes. So it’s really important to make sure that everybody who uses these basins is mindful of how they use them to make sure they are not overusing them or diluting them in different ways.” Because plumes do not always stay in one place, people can be affected in areas far away from where the original contamination occurred, she adds.

water remediation

TIGHT QUARTERS | The UV treatment facility at North Hollywood.

The LA Dept. of Water and Power negotiated settlements with Lockheed Martin and Honeywell in 2018 and 2019, respectively, that require the manufacturers to pay for cleanup of regional groundwater Superfund sites containing Cold War-era pollution.

In 2021, the department negotiated a second settlement with Honeywell to expedite work. Together, the agreements could generate more than 5 billion gallons of drinking water from groundwater annually for the next several decades, department officials say. EPA is overseeing the work at these sites, which is ongoing. 

Projects Underway

The department has initiated construction projects to remediate three sites within the basin that collectively comprise the San Fernando Groundwater Remediation project: North Hollywood West, North Hollywood Central and Tujunga Well Field. The latter is located in the eastern basin, closer to the rim of the San Gabriel Mountains. 

EPA now is contemplating a fourth site in the basin’s southern well fields, depending on the outcome of an ongoing remedial investigation.

The department is overseeing work to comply with a federal framework for coordinated responses to hazardous waste cleanups. The interim response actions being implemented at the three sites currently under construction are the result of individual remedial investigation and feasibility studies, the department says. 

The total cost of the three projects already under construction is set to top $700 million, but may be higher if a fourth treatment facility is built in the southern well fields near Pollock. 

North Hollywood, Calif., project site

HEAVY LIFT | At the North Hollywood, Calif., project site (above), the construction crew opted to use one large crane that could be placed in a central location, rather than multiple smaller cranes.

The department has received about $309.8 million in grant funds through California’s Proposition I initiative, a 2014 voter bond measure that authorizes the state water control board to fund up to 50% of major water infrastructure projects. Department consultant Hazen & Sawyer developed the remedial plan for the North Hollywood West facility, which will treat 16,000 acre-ft annually. Agency employees are completing construction work.

For the other two sites now being built—North Hollywood Central, with an annual treatment capacity of 28,000 acre-ft, and Tujunga Well Field, with annual treatment capacity of 43,000 acre-ft—the department opted to use progressive design-build. Kiewit is the prime contractor, and Stantec is engineer. Design work finished in March 2021, with construction set to wrap up by summer 2023. 

The North Hollywood Central and Tujunga projects use a similar approach to treat the contaminated wells, although site geography differs. Both use granular activated carbon tanks for volatile organic compounds, with that technology and ultraviolet advanced oxidation for wells contaminated with T1,4 dioxane. All treated water is disinfected using a combination of  chlorine, fluoride and ammonia before it is piped into the drinking water distribution system.

Tight Space

While the Tujunga site spans several acres, the North Hollywood site is just a 150-ft x 130-ft city block surrounded by homes that were inhabited until recently. “The treatment train and the technology is the same here as at Tujunga, says Blake DePaola, Kiewit project manager for the North Hollywood site. “We’re just on a much more reduced footprint.” The smaller footprint, however, has required considerable coordination and logistical planning with no room for storage of equipment and materials, he says. 

Working directly adjacent to residential properties presented another challenge at North Hollywood, DePaola says. Although the water department was able to purchase most properties closest to the treatment facility through a buyout program to be able to build all the structures that were needed for the project, the rapid rise of COVID-19 and ensuing eviction moratoriums presented added hurdles, DePaola says.

The delivery method allowed construction to stay on schedule, says Jose Rubalcava, department civil engineer and design manager for the basin groundwater remediation project. “We didn’t have to wait until the design was fully complete, go out to bid and then award it to a contractor,” he says. Having the contractor on board early allowed input into the project’s overall design, and enabled better design and construction team collaboration.  

Diversifying Portfolios in Face of Climate Change

sustainability demonstration sustainability demonstration
GREEN FUTURE | L.A. Mayor Eric Garcetti (top photo, holding sign) called for 100% of the city’s wastewater to be recycled by 2035. Above, a protester at the May 12 California Coastal Commission vote on a new desalination plant in Huntington Beach.

Beyond groundwater, California is ramping up programs to recycle water supplies for drinking, aquifer replenishment and agricultural uses. The Los Angeles Dept. of Water and Power and LA Sanitation and Environment have developed an ambitious plan to achieve Mayor Eric Garcetti’s 2019 Green New Deal goal to recycle 100% of available wastewater for beneficial reuse in Los Angeles by 2035.

The $16.8-billion program, called Operation NEXT, includes multiple projects, but at its heart is the retrofit of the Hyperion water reclamation facility with advanced treatment processes to produce 217 million gallons per day (mgd) of purified recycled water. The existing plant treats an average daily flow of 260 mgd to secondary treatment standards, with about 27% of that used for irrigation and other non-potable uses.

According to Rafael Villegas, water department program manager for Operation NEXT, some version of the plan has been around for almost 20 years. But it had not progressed beyond the idea stage until recently, propelled by intensifying effects of climate change and more demand for local water sources. 

The department is partnering with other agencies to conduct pilot studies and demonstration projects to evaluate how membrane bioreactors, biological activated carbon and other technologies perform in producing drinkable recycled water. 

Because the state currently does not have regulations for direct potable reuse, California agencies are conducting these pilot studies and demonstration projects to help “inform the regulatory process” when rules are expected to come out sometime in 2023.

The water and sanitation departments and other partners will have a better sense of “what can and what can’t be approved” for full-scale projects, Villegas says. 

The water department recently hired Jacobs to evaluate its pilot projects and develop an Operation NEXT master plan. Rich Nagel, a Jacobs vice president, notes that getting the mix of technologies right is important. Los Angeles “is looking at a combination of indirect and direct potable … so what is the right treatment for the purpose? Not overtreating, or undertreating, but [finding] the right level.” 

Desalination Option

At the same time, desalination continues to be an option, or at least a consideration, although the California Coastal Commission’s rejection last month of a new proposed Poseidon facility last month was a blow to advocates. The firm has a $900-million operating plant in Carlsbad. But other smaller desalination facilities have been built, including one in Santa Barbara. Another is being considered in the Doheny Beach area outside of Los Angeles. 

Desalination “can definitely be part of the portfolio in California,” says Newsha Ajami, chief development officer for environmental research at Lawrence Berkeley Lab in Berkeley, Calif. “But is there a way that we can do this in an environmentally thoughtful way” when there is sufficient demand for it? she asks, noting that “there are still so many opportunities to reuse water multiple times.”

Whatever technologies are adopted, a paradigm shift is necessary, suggests Villegas. The coming years will challenge water agencies to think more creatively about water. Historical tree-ring data show two major megadroughts in California over the past 2,000 years. One lasted 120 years, the other was 70 years long. 

Although it is unknown how long the current drought will last, climate change and rising population levels will only exacerbate pressure on existing systems and infrastructure, according to Villegas. “The model we have for water supply today—we’re going to have to revisit that and think differently about it,” he points out. “How does an organization change to get itself ready to be able to take on a program of this size considering everything else that we already do?”


By Pam McFarland

Keeping on Track

Because of deadlines associated with the Prop 1 funding, Stantec delivered the design through a series of packages. This enabled Kiewit to start and complete work sooner, says Mike Watson, a senior vice president and major projects lead in Stantec’s water group. The firm provided separate packages for each site, and within those, developed 27 separate design packages to provide Kiewit more flexibility in planning and building treatment facilities and related infrastructure. He says the work “could not have been done” otherwise in the time allowed, with supply-chain and COVID-19 related constraints.  

The department had anticipated being able to demolish nearby properties at the North Hollywood site. But the project team could not locate the UV treatment process train where planned, due to the pandemic and other circumstances. It instead installed the system where existing chemical disinfection units were and built a temporary chemical disinfection system to keep the facility running. 

At the Tujunga site, Kiewit drastically reduced the time the wells would be out of service—to just six weeks—by adding a 30-in.-dia pipe to convey about 27 million gallons per day of water from three wells without any contamination to the water distribution system, says Daron Toll, Kiewit project manager at the Tujunga site.

Originally, the construction team would have had to close off the water supply for the project’s entire duration—nearly two years to allow for the wells and associated infrastructure to be tied into the plant, and for treatment systems testing and commissioning. But with three non-contaminated wells, that plan was not palatable, he says. Crews added the pipe to allow water from non-contaminated wells to bypass the new treatment trains and flow into disinfection and then the water distribution system. 

Beyond Los Angeles

Groundwater contamination extends beyond the San Fernando Valley basin, with hundreds of wells throughout California thought to be contaminated. 

But with pumping and treating contaminated groundwater a costly endeavor, Maguire of the state water control board says some wells are simply too contaminated to treat.  “It’s really a case-by-case scenario,” he says. “Is it too hot to touch, or is it [a site] that we can address and rely on in the near term as drinking water or for agricultural supply?”

Preventing Well Depletion

Many groundwater wells have also been overdrawn. The state’s 2014 sustainable groundwater law prevents overreliance on the same wells to the point of depletion. It requires agencies dependent on high- and medium-priority basins in California to develop plans for how best to manage their groundwater resources. 

Under the law, the groundwater-dependent agencies must be able to recharge as much as they pump within 20 years. According to the Water Control Board, bringing pumping and recharging into balance will create a “drought buffer” during dry periods. “Before [the law], groundwater usage was basically the Wild West. You could pump it and use it and you didn’t have to tell anybody about it,” says Steve Stuart, a principal hydrogeologist at Encinitas, Calif.-based consulting firm Dudek. 

Drinking Water Distribution System

DRINKABLE | Treated groundwater at the sites will go through disinfection with chlorine, ammonia and fluoride before being pumped into the drinking water distribution system

The firm was involved in early discussions related to the groundwater management law, and wrote nine sustainability plans for basins in southern California, he says, adding that some of the plans could prove controversial and even be litigated because they place limits on how much water can be drawn from groundwater sources, and by whom. 

In June and November 2021, the state Dept. of  Water Resources released its assessments of the first six of the 42 plans submitted in 2020, with the rest released in January. Plans that have been approved can move forward to implementation. 

To gain a better understanding of changing geological conditions in the groundwater basins, California is mapping them using drones and helicopters equipped with airborne electromagnetic technology. Building on work begun at Stanford University, the water resources agency says it is collecting data to develop continuous images of large aquifers, which will provide a standardized dataset to implement the law. 

The data will also help the state and local water agencies identify potential basins where additional groundwater recharge or replenishment projects could be done. 

Funding Mechanisms

More than 32% of non-petroleum-contaminated groundwater sites in California are not being addressed because there is no responsible party linked to the pollution, or that entity or entities cannot pay for the cleanup, according to California’s water board. 

However, some groundwater remediation efforts in the state may now be accelerated by an infusion of funding from the federal Infrastructure Investment and Jobs Act enacted last November. It allocates $55 billion for water and wastewater infrastructure, including $10 billion for remediation related to Per- and Polyfluoroalkyl Substances (PFAS). Some PFAS chemicals have been found in groundwater wells in California. 

The infrastructure funding law also significantly boosts funds available through state revolving loan programs. 

Additionally, a variety of state and local programs exist to support new infrastructure projects, including the Site Cleanup Subaccount program, known as SCAP, which provides grants to sites that pose an immediate risk to a community.  

Community Support

Environmental groups have been supportive of the cleanup efforts. The Sierra Club has advocated at the local and state levels for funding to support the San Fernando basin cleanup program and others like it, says Charming Evelyn, co-chair of the advocacy group’s California Water Committee. “We are a big proponent of cleaning up groundwater and reusing it as a local source … and [we advocate] for water agencies to get the funding they need to keep the water system clean,” she contends.

Of contaminated sites not being addressed, nearly half are located in disadvantaged, underserved or rural communities, the water board says. A continuing concern is that smaller agencies may not have the resources or technical expertise to launch major capital programs.  

A small agency that may serve only 2,000 people “cannot raise rates to cover the costs” for the work that is needed, Evelyn says. 

Also, some of the people most harmed by groundwater contamination are indigenous or people of color who live in under-resourced areas, she says. Smaller or disadvantaged communities “should be at the front of the line to make sure they get the money that they need,” Evelyn adds. “Unfortunately, this is not the way that it works. So it’s a scramble.”