Scientists: California needs more groundwater data
The more scientists study California’s declining supplies of groundwater, the more they’re emphasizing one basic point: We still don’t know nearly enough about the water in our aquifers, and we need a lot more data.
That was one of the main takeaways in separate research by two groups of Stanford researchers last week.
In one study, scientists used data from thousands of oil and gas wells to examine water deep beneath the Central Valley and calculated there are vast quantities of groundwater more than 1,000 feet underground – the maximum depth considered in previous estimates. Their research underscored the fact that no one is monitoring deep aquifers despite the threat of potential contamination by the oil and gas industry.
In another report, researchers surveyed a group of water managers across California and found many agencies lack the data they need to adequately make decisions about groundwater.
For one thing, most areas of the state don’t have meters on all of the wells that are running, “so the agencies that are trying to manage that groundwater have no idea how much groundwater is actually being pumped out of them,” said Tara Moran, a researcher who leads the sustainable groundwater program as part of Stanford University’s Water in the West program.
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She said her group found in their survey that “a lot of data are either missing or highly uncertain,” and that the information collected often isn’t shared between agencies to enable decision-making.
The results show just how far California has to go as water managers take steps to follow through on the landmark 2014 law that aims to bring about sustainable management of groundwater.
And while the latest research reveals major gaps in groundwater data, other efforts to boost statewide controls on well-drilling have recently foundered. A bill that would have clamped down by prohibiting the drilling of most new wells in California’s most water-stressed areas, encountered strong opposition and died in the Legislature last week.
With aquifers under enormous strains during California’s five-year drought, scientists have been pointing to a need for better estimates of the amounts of water that can economically be pumped, as well as more information about water quality, salinity, natural recharge and the amounts being extracted, among other variables.
Moran said the new research on deep groundwater, in which she didn’t participate, shows how information from oil and gas wells can be valuable in helping to fill in some of the blanks. She said the study also highlights the considerable uncertainty that remains.
“We really don’t know enough about our groundwater systems,” Moran said.
Water deep underground
To study California’s deep reserves of groundwater, Stanford scientists Mary Kang and Robert Jackson looked to the main industry that regularly cores thousands of feet into the Earth: oil and natural gas. They analyzed information from 360 oil and gas fields across eight counties, including depth data for more than 34,000 oil and gas wells.
In their research, which was published in the Proceedings of the National Academy of Sciences, they expanded on previous estimates by going as deep as 3,000 meters, or nearly 1.9 miles, beneath the farmland of the Central Valley. Based on the data, they calculated the quantity of fresh groundwater at 2,700 cubic kilometers, nearly triple the amount in previous estimates.
It’s not clear how much of that water might be economically feasible to pump and use in the future. Much of the water is deeper underground than existing wells can reach.
Then there’s also the issue of salinity. Some of the deep groundwater has higher salt concentrations than water found at shallower levels, so desalination or other treatment would be necessary. In their estimate, the researchers included water with total dissolved solids of up to 3,000 parts per million, much saltier than the drinking water delivered to taps, which has total dissolved solids under 1,000 parts per million.
Nevertheless, the scientists said their estimates show substantial water reserves that may be usable in the future and that ought to be monitored and protected.
“There is quite a bit of groundwater that’s of good enough quality that we could potentially use with relatively little treatment, or less treatment than we thought,” said Kang, a postdoctoral researcher at Stanford’s Earth System Science Department.
While the scientists call it a “windfall” of water, they also say their findings raise some concerns. If California keeps drawing water from deeper underground, that would accelerate the sinking of land in some areas. The ground has already been sinking by about a foot and a half per year in parts of the Central Valley due to heavy pumping, causing damage to canals and other infrastructure.
Kang and Jackson also found many cases of oil and gas activities occurring in aquifers with usable water. More monitoring is crucial, Kang said, to determine whether those vulnerable aquifers are being contaminated.
In Kern County, for example, where the petroleum industry has flourished alongside agriculture, the researchers discovered about one-fifth of oil and gas projects are occurring in underground freshwater sources, while the remainder are occurring in aquifers with more saline water.
Due to the risk of potential contamination of usable water, Jackson suggested state officials consider requiring additional permits and data.
“We’re lucky to have some extra water, but we need to think about how much to use, how much to save and how to protect it for the future, too,” said Jackson, a professor of environmental science who has carried out other research on fracking and water quality.
“We’re proposing a conversation about how best to use this freshwater resource,” Jackson said. “We’d like to see more data collection and data transparency for groundwater in general.”
Jay Famiglietti, the senior water scientist at NASA's Jet Propulsion Laboratory in Pasadena, said hydrologists have known that basins such as the Central Valley hold large quantities of brackish and saline water deep down.
He said using data from oil and gas fields is a great idea and researchers should do more of it. But taking those estimates from small-scale well fields and scaling them up to the entire Central Valley is difficult, he said, and there is a great deal of uncertainty.
Famiglietti, who is also a professor at the University of California, Irvine, said the study “points to the fact that we need a comprehensive, detailed hydrogeological exploration program, not only in California but in the other major aquifers of the United States.”
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“The important message is that someday it may be economically and technologically and environmentally feasible to extract that water,” Famiglietti said. “And for that reason, we should begin thinking about protecting those waters today.”
How much of California’s deep groundwater is actually going to be usable will depend on a variety of questions ranging from economics to geology, said Peter Gleick, president of the Oakland-based Pacific Institute. “There’s a huge difference between a theoretical estimate of how much groundwater there may be and a practical estimate of what we might ever be able to tap into.”
During the drought, farms in the San Joaquin Valley have been pumping heavily to make up for the lack of surface water, and thousands of people in rural communities have been left with dry wells.
“Even if there’s a lot down there, we know that our current use is unsustainable in many parts of the valley,” Gleick said. And if Californians eventually decide to use deeper reserves, they’ll be consuming more of the “fossil water” that has been underground for tens of thousands of years.
“This is more like oil in the ground than it is like water in a river or a reservoir,” Gleick said. “It’s not renewable.”
Insufficient data
To diagnose the gaps in California’s groundwater data, Moran and other Stanford researchers prepared a survey and distributed it by email through two listservs that focus on groundwater issues.
They received responses from about 100 people and focused their analysis on answers from about 50 of those people who have management authority over a specific area. The participants included employees of water agencies, officials of county, city and tribal governments, and farmers.
In one question, the participants were asked which improvement would most help them better manage groundwater. The top answer, with 46 percent, was “additional data.”
In another question, 58 percent indicated they see a need for “standardized data collection methods and a common data-sharing platform.”
“Right now you could have 15 or more agencies within a groundwater basin all collecting their own data in their jurisdictional area, but they may not be sharing it with other agencies,” Moran said. “So if you actually need to make decisions at the basin scale about how to manage, those data ultimately need to be integrated between agencies and shared.”
The survey involved researchers with the Water in the West program and also the Stanford Law School. They found that many local agencies in California don’t have dedicated groundwater monitoring wells.
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Based on the survey, Moran and her colleagues recommend a list of changes for agencies to build upon the requirements in the 2014 Sustainable Groundwater Management Act.
Among other things, they suggest local agencies should expand networks of monitoring wells; meter more wells to track the amounts pumped; and use their authority under the groundwater law to monitor private wells.
They’re also calling for state and federal officials to require local agencies to use consistent monitoring standards and a common data platform so that information can be shared and used better.
Legislation scrapped
California’s groundwater law gives local agencies a long grace period to meet various requirements – in many cases until 2022 to adopt plans for sustainable water use, and an additional 20 years to bring aquifers into balance.
Despite the law, a well-drilling boom has continued in areas where groundwater levels have been dropping. A bill introduced by Sen. Lois Wolk, D-Davis, would have clamped down by prohibiting the drilling of most new wells in places where aquifers are in “critical overdraft,” and by requiring cities and counties in other areas to start requiring permits.
The bill, SB 1317, was strongly opposed by a variety of influential organizations, such as the Agricultural Council of California, the Association of California Water Agencies and the California Building Industry Association.
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The legislation was pulled from consideration last week before it reached the Water, Parks, and Wildlife Committee. Craig Reynolds, Wolk’s chief of staff, said supporters were far short of the necessary votes.
Debi Ores, an attorney and legislative advocate for the Visalia-based Community Water Center, said her organization backed the bill because it would have slowed the declines in the state’s most vulnerable aquifers.
“What we’ve learned is people are very protective over their ability to pump groundwater however they choose,” Ores said, “regardless of whatever the negative impacts that pumping may have on their neighbors or the basin as a whole.”
Contact Ian James at ian.james@desertsun.com or on Twitter: @TDSIanJames.
More information
Stanford scientists’ study of deep groundwater in California
Stanford report: “From the Ground Down: Understanding Local Groundwater Data Collection and Sharing Practices in California”