As drought persists, crucial groundwater supplies dwindle

The cap of a well used to monitor groundwater samples in Gilroy. (Photo: Matthew Corley, via Shutterstock)

More than 60% of  California’s groundwater wells are operating at below-normal levels, endangering much of the Golden State’s population that relies on the precious resource.

Although relatively unknown to many Californians, who see water supply in terms of rivers, streams and reservoirs, groundwater is a hugely vital source that is largely invisible.

“[Groundwater] represents anywhere from 40 to 60 percent of our total water supply in the state. During dry years, it’s approaching 60-plus,” said Tim Godwin from California’s Department of Water Resources (DWR). “Upwards of, like, 85% of our populace relies on groundwater in some capacity or another.”

A mere 10% of wells are functioning at above-normal levels.

But California’s groundwater supply is being gradually depleted and over-extracted.

Across California,  nearly two-thirds of groundwater wells are operating below-normal levels, while only 26% are operating at acceptable levels, according to the DWR’s California Groundwater Live tracking website.

A mere 10% of wells are functioning at above-normal levels. Much of the depletion is occurring within the Sacramento Valley, the San Joaquin Valley and the Central Valley, the centers of California agriculture.

Groundwater is water stored “within the small spaces between soil particles and fractured rock,” according to California’s DWR. This water is accessed via wells and pumps and makes up 38% of California’s water supply. This percentage jumps to 46% during dry and drought years as “municipal, agricultural, and disadvantaged communities” depend on groundwater to live.

Godwin spent his entire career working in groundwater and continues to do so in 2022.

California’s DWR, established by the state Legislature in 1956, manages the state’s water resources to ensure water supply and human and natural environments are all maintained and protected. The department also manages the State Water Project (SWP), the vast system that supplies water to nearly 27 million Californians and 750,000 acres of farms.

Additionally, the SWP provides “flood control, hydroelectric power generation, recreational opportunities, and ecosystem enhancements,” DWR notes.

Godwin is the technical and policy adviser to the deputy director for the Sustainable Groundwater Management Office at the DWR. He is a supervising engineer and geologist who is a self-described hydrogeologist. Godwin spent his entire career working in groundwater and continues to do so in 2022.

The Sustainable Groundwater Management Act (SGMA) is the program that Godwin highlighted as the forefront governmental effort to regulate groundwater usage and move groundwater wells and basins toward more acceptable and sustainable levels.

“[SGMA] really focuses in on what we determine to be as high and medium priority basins within the state. Those high and medium priority basins represent approximately 96% of the total pumping in the state,” explained Godwin.

We still had many concerns with the three-bill package and that is why Farm Bureau asked the governor to veto the measures at the time.”

SGMA is made up of three bills, AB 1739, SB 1168 and SB 1319, signed in 2014 by Gov. Jerry Brown requiring local agencies to form Groundwater Sustainability Agencies (GSAs) to develop Groundwater Sustainability Plans (GSPs). These GSPs are made to reach long-term sustainability in groundwater basins at a local level.

The California Farm Bureau (CFB) was a force in amending the SGMA, establishing greater language to protect groundwater rights, as well as increased timelines for local entities and relaxed requirements for specific basins. The bureau remained opposed to the bills making up the SGMA, asking the governor to veto the measures.

“Although local management is consistent with our policy, Farm Bureau and other agricultural organizations actively worked to resolve a number of issues in the act,” the group noted on its website.'”

The Bureau added:  “Notwithstanding the amendments we secured, we still had many concerns with the three-bill package and that is why Farm Bureau asked the governor to veto the measures at the time.”

The CFB worked to protect local farms and ease regulations on them from the proposed and enacted SGMA.

Over-pumping groundwater sources, however, can lead to dangerous consequences.

Regions like the San Joaquin Valley have a unique geology with a surplus of clay in the soil that eventually compresses after the water in the ground is extracted, says Chris Austin, founder and editor of  Maven’s Notebook, a respected water policy website.

This compression causes the land on top to gradually sink, resulting in a phenomenon known as land subsidence.

“Land subsidence is a big issue in the San Joaquin Valley,” Austin said.

“You can either add more groundwater supply or you just simply are reducing the amount that is pumped.” — Tim Godwin

When extraction is above replenishable levels, the ground can, over time, sink.

Austin notes that the Sacramento Valley doesn’t experience as much of a problem with subsidence as the soil lacks the clay that would compress and lead to sinkage.

As harmful as subsidence is, though, it is not without its potential solutions.

“Step one: we need to reduce the pumping. You can either add more groundwater supply or you just simply are reducing the amount that is pumped,” Godwin said.

How can California add to or recharge its groundwater? Godwin says we need to look where the depletion has already occurred.

“We have a tremendously large storage vessel right under our feet,” Godwin explains. “We’ve depleted our aquifer systems for decades now and there’s a lot of available space to recharge these waters and make those waters available through groundwater pumping.”

The main factor preventing California from reaching its proposed solutions to the groundwater crisis? Money.

Groundwater recharge occurs by increasing water supply into an aquifer through means such as redirecting water via “canals, infiltration basins, or ponds,” according to the United States Geological Survey (USGS). Irrigation furrows, irrigations wells and sprinkler systems can also function for artificial recharging of groundwater.

“Recharge is, I would say, low-hanging fruit when it comes to opportunities to store more water. Its not only storing more water but it’s storing water in a way that is really isolated from the effects of evaporative processes,” said Godwin.

The main factor preventing California from reaching its proposed solutions to the groundwater crisis? Money.

“There’s nothing stopping this, honestly. The challenge is funding,” said Godwin. “These projects are not inexpensive.”

Godwin explains how allocating water into groundwater systems is very costly, as is treating water quality to be suitable for drinking.

The quantity of groundwater is a concern integral to California’s water supply, but the quality of the water may be of concern as well.

California’s historic drought continues unabated and its consequences are readily apparent, even to the average consumer.

“We also are experiencing more and more domestic wells going dry, so people’s drinking water sources are becoming impaired because of groundwater depletion,” said Godwin.

In March, Gov. Newsom signed Executive Order N-7-22 to declare a drought emergency in all of the state’s counties as a result of “extreme and expanding drought conditions.” The order notes climate chance as a factor serving to increase the drought’s impacts on California’s community, environment and economy.

The front line against the drought’s effects on groundwater remains the DWR’s GSAs and their local programs to combat groundwater depletion. Over 260 GSAs were created, said the DWR, in over 140 basins, and more will continue to be formed as fit the state’s water needs.

“They’ve all taken tremendous strides in the right direction to define what sustainability is in their local basins and start to develop those projects and actions that are going to help them achieve that sustainability by 2040,” Godwin said.

Without this sustainability, the drying up of wells, reduction of water in streams and lakes, water quality decline, increased costs of pumping and lans subsidence are all potential ramifications of excessive groundwater pumping, summarizes the USGS.

The quantity of groundwater is a concern integral to California’s water supply, but the quality of the water may be of concern as well. Godwin, though, says Californians shouldn’t worry too much.

He continues to say that, as groundwater wells extract deeper into the ground, the quality of the water declines and concentrations of nitrate and arsenic tend to rise. These, Godwin says, are concerns for the GSAs across the state to keep in mind when implementing their plans.

“However, SGMA also incorporates that for agencies to be aware of groundwater quality conditions and to manage their basins as to not cause those conditions to get worse,” he said.