California hasn’t recycled enough water, they say the state should treat and reuse more wastewater to help address the chronic shortage in the Colorado River, according to a new report by UCLA researchers.
Researchers analyzed data from large wastewater treatment plants in seven states that rely on the Colorado River water and found that California recovered only 22% of its treated wastewater. This lags far behind the two driest states in the country: Nevada, which is recycling 85% of its wastewater, while Arizona reuses 52%.
this ReportAccording to 2022 data, other states in the Colorado River Basin are found to be behind, with New Mexico recovering 18%, Colorado 3.6%, Wyoming 3.3%, and Utah less than 1%.
With federal support, California and other states should expand investment in water recycling facilities to help the requirements facing the region, researchers say Greatly reduce water use To prevent the reservoir from falling from falling Key Level. They say the Southwest needs to prioritize water recovery to accommodate drought Become more intense and lasting Global warming.
“We are facing a hotter, drier future and we need to actively recycle water if we want to ensure sustainable, resilient water supply,” said Noah Garrison, a water researcher at the UCLA Institute of Environmental and Sustainability.
“There is a huge opportunity here,” the garrison said. “We need to create these new, resilient water sources.”
Research shows that in these seven states, an average of 26% of municipal wastewater is recycled.
If California and other states pursue the goal of recycling 40% or 50% of wastewater, this would go a long way to address the gap between supply and demand between rivers, the researchers said. They calculated that if each state even reached 30%, that would generate more than 450,000 acres of water each year—almost as much as the total annual use in Los Angeles.
“The moderate gains in these moisture reuses could have a huge impact on Colorado,” said Mark Gold, an adjunct professor and director of water scarcity solutions at UCLA’s Natural Resources Defense Commission.
The greatest potential lies in California, which uses more Colorado River water than any other state. Water flows to the aqueduct and canal Desert farmland and cities from Palm Springs to San Diego.
Some urban wastewater in Southern California is Treatment and reuse Irrigate golf courses and parks, while Orange County has a system Purify wastewater And put it in the groundwater basin for use as drinking water.
Other treated wastewater is Drain into rivers or oceans.
Penstocks at a genetic pumping plant near Lake Havasu transports Colorado River water to Southern California.
(Brian van der Brug / Los Angeles Times)
The researchers compiled statewide data for all seven states in the Colorado River Basin, including river-dependent and other river-free areas.
Researchers say 29% of wastewater is currently being recycled from Ventura to San Diego County, the researchers said. Establishing three large planned water recycling projects will enable the area to be reused by more than 56%, according to state data.
Once fully built, these three facilities are planned Santiago,,,,, Los Angeles and Southern California’s metropolitan water areawill greatly increase local water supply. The report said the total cost of the three projects and the new water distribution system could exceed $25 billion.
Although the cost will be huge, building these projects should be seen as important infrastructure improvements, Gold said.
“We obviously do not manage water in a sustainable way, and the water recycled is very critical, like the way we do it,” Gold said.
The researchers say the work will require significant state and federal investments and should be carried out urgently.
The Colorado River provides water to cities from Denver to Los Angeles, 30 local tribes and agricultural communities from Rocky Mountain to northern Mexico.
Since 2000, the river has long been overused due to persistent dryness and its reservoirs have dropped sharply. The average flow of rivers has shrunk by about 20% since 2000, and scientists estimate that half of this decline is half the Caused by global warming Powered by fossil fuel combustion.
As temperatures increase, flow drops are expected to worsen.
The U.S. canals bring Colorado River water into California’s Imperial County.
(Caroline Cole/Los Angeles Times)
“We are unable to take on the advancement of water recycling due to the importance of reliability and climate resilience,” Gold said.
The average difference between average supply and demand between rivers is estimated to be between 2 million acre-foot and 4 million acre-foot, Gold said. A large portion of this can be offset by recycling more water.
“But without major federal and state investments, that wouldn’t happen,” Gold said.
The researchers called on the Federal Environmental Protection Agency to set water reuse goals and asked the state government to commit to the goals (such as 30%, 40%, or 50%) and to work with other agencies to obtain funding. They also said states need to collect better data on water recycling.
Several states lack basic information and researchers had to call the treatment plant alone to understand how much water is being processed and reused.
“The lack of sufficient data is a major obstacle,” the garrison said. “The fact that what is happening is hardly aware of is a real and growing problem.”
Researchers say there is a U.S. in California The most comprehensive regulations On the recycled water, other states are also led to track data about reuse. They said the country adopted ambitious water recovery targets in 2009 National Strategy adopted in 2022.
“The real problem is that in 15 years, we have made little progress,” the garrison said. “It’s time for California to start investing heavily in this area, especially given the uncertainty surrounding the water in the Colorado River Basin.”
Board Chairman E. Joaquin Esquivel said that over the past few years, the state water control board has provided $1.4 billion to projects that will produce an additional 125,000 acres of recycled water each year.
“The increased recycling water is a top priority for the state and a key part of the governor’s Newsom strategy, which is the expected 10% water supply by 2040 due to hotter, dryer conditions,” Esquivel said in an email.
He said that despite the huge progress made by the state and Southern California institutions in recent years, “continuous investment and initiatives are essential to leverage the full potential of recycled water and simultaneously reduce dependence on the Colorado River.”
