A sudden sinking event is putting California’s water crisis back in focus

California farmland starts sinking faster

Imagine farmland dropping while you are standing on it. New research found that parts of the Sacramento Valley sank abruptly during California’s 2020–2022 drought as heavy groundwater pumping lowered underground water levels.

Researchers found subsidence exceeding 1 foot per year in some areas, with the fastest rates approaching 20 inches annually. The concern is especially serious because researchers found that large areas had shifted into predominantly irreversible compaction, permanently reducing part of the aquifer’s storage capacity.

The aquifer crosses a critical threshold

The Sacramento Valley has experienced land subsidence before, but researchers found something unusual beginning around 2021. Ground movement suddenly accelerated after groundwater levels fell below thresholds that underground sediments had previously experienced.

That distinction matters. Some land can rise again when aquifers refill, but severe compaction can permanently squeeze layers of clay and sediment. Once that happens, part of the underground space that once stored water can disappear.

Some of the damage cannot rebound

The Sacramento Valley study identified particularly severe sinking in agricultural areas of Colusa, Glenn, and Yolo counties. Researchers say some areas crossed from mostly reversible movement into permanent land subsidence during the drought.

That makes this more than a changing landscape. Permanent compaction can reduce groundwater storage while shifting canals, roads, wells, and other infrastructure. It can also change how water moves across low-lying farmland during floods.

Groundwater pumping changes the ground

Subsidence starts beneath the surface. When large amounts of groundwater are pumped from an aquifer, pore water pressure falls. That causes more of the weight of the overlying sediment to be carried by the aquifer’s grain structure, which can compact fine-grained layers and lower the land surface.

During smaller changes, the ground may rebound after groundwater returns. If water levels fall far enough, however, fine-grained sediments can compact permanently. That leaves the surface lower, which can reduce the aquifer’s future storage capacity during dry years.

Drought pushes farmers toward wells

Why pump so much groundwater? During dry periods, farms often receive less water from rivers, reservoirs, and canals. Wells serve as an important backup, helping keep crops alive when surface water supplies are limited.

That creates a difficult tradeoff for growers. Pumping protects crops and farm income in the short term, but excessive withdrawals can lower groundwater levels and increase subsidence. California’s repeated droughts have made that balance harder to manage.

Sinking can shrink water storage

An aquifer is not simply a giant underground lake. Water occupies pores and spaces between layers of sand, gravel, silt, and clay. Heavy pumping can squeeze some of those spaces closed.

That is why irreversible subsidence creates a double problem. Permanent compaction lowers the land surface while also reducing the pore space available to store groundwater.

Fun fact: Researchers estimated roughly 158 cubic kilometers of loss of Central Valley groundwater storage from predevelopment conditions through 2019.

Canals can lose carrying capacity

Sinking land can cause trouble far beyond the field where groundwater was pumped. Canals rely on carefully planned elevations and slopes to move large amounts of water, so that uneven subsidence can reduce their carrying capacity.

California has already seen this problem farther south. California water officials reported in 2025 that subsidence had reduced the California Aqueduct’s capacity by as much as 44% in affected reaches, limiting the state’s ability to move water efficiently during both wet and dry periods.

California has seen worse before

The Sacramento Valley findings are alarming, partly because California already knows what severe subsidence can do. The San Joaquin Valley has experienced decades of sinking, largely linked to groundwater withdrawals.

Historic declines there reached many feet in some locations, damaging canals and changing land elevations. Researchers now worry that northern Central Valley areas could follow a similar path if groundwater levels repeatedly fall below the point where permanent compaction begins.

California’s groundwater law has a deadline

California responded to long-term groundwater problems by passing the Sustainable Groundwater Management Act, or SGMA, in 2014. The law created a new framework for managing heavily used groundwater basins through local agencies.

Those agencies develop plans intended to avoid major problems such as chronic groundwater declines and significant land subsidence. Most affected basins are expected to reach sustainable conditions by the early 2040s.

Fun fact: SGMA was California’s first statewide framework requiring long-term sustainable management of major groundwater basins.

Wet winters cannot fix everything

Rainy years help recharge aquifers, but they cannot automatically undo permanent damage. The study showed that affected areas failed to rebound as groundwater levels recovered seasonally during 2021 and 2022. Lead author Stacy Larochelle has since said that newer observations suggest many locations still have not returned to their earlier elevations despite wetter years following the drought.

That is why managers increasingly focus on capturing water during periods of heavy rain in California. Managed aquifer recharge sends excess surface water underground, helping rebuild groundwater reserves that farms and communities may need during future droughts.

Satellites reveal changes from space

Researchers did not rely only on wells to detect the sinking. They combined groundwater records with high-resolution satellite measurements that can track tiny changes in land elevation across large areas.

That gives scientists a broader view than individual monitoring stations alone can provide. Repeated satellite observations can reveal where subsidence is accelerating, helping water agencies identify trouble spots before sinking causes more damage to farms, roads, canals, or other infrastructure.

California agriculture depends on water

The sinking matters nationally because California is an agricultural powerhouse. Irrigation supports millions of acres growing everything from fruits and nuts to vegetables, rice, and other crops that reach stores across America.

Groundwater becomes especially important when surface supplies fall short. But protecting agriculture over the long run means balancing today’s pumping with tomorrow’s water needs, infrastructure, groundwater storage, and the aquifers’ ability to withstand future droughts.

For another water update tied to drought risk, groundwater pressure, and future supply, see why scientists warn nine U.S. regions could face severe shortages by 2035.

The sinking sends a warning

The Sacramento Valley is not disappearing overnight, but the sudden acceleration sends a warning. Once underground sediments are permanently compressed, simply waiting for another rainy winter may not restore everything that was lost.

California now faces a long-term choice: conserve more groundwater, expand recharge, improve monitoring, and adapt farming where needed. The goal is to keep water available without allowing the land and the aquifers beneath it to keep shrinking.

For another California water update tied to housing growth, limited supplies, and local planning, see why an I-5 city is moving ahead with hundreds of new homes despite shortages.

Could California’s sinking land be the warning sign that water problems are getting harder to ignore? Share your thoughts and drop a comment.

This slideshow was made with AI assistance and human editing.

Read More From This Brand:

• New Mexico water shortage hits town and immigration detention center
• Idaho water shortage puts irrigation, towns, and food supply under pressure
• Water shortages push a Texas city closer to being the first in the U.S. to run dry