CORCORAN, Calif. — Earlier this year, as floodwaters rushed toward the San Joaquin Valley city of Corcoran — home to roughly 20,000 people and a sprawling maximum-security state prison — emergency workers and desperate local officials begged the state for help raising their levee.

Farmers, meanwhile, were frantic as the basin’s phantom lake reemerged for the first time in 25 years and floodwaters surged onto croplands that had not flooded in modern times. The same overpumping that was sinking Corcoran had caused geologic transformations across the basin. What was once high ground suddenly wasn’t; infrastructure critical to drainage had in some cases shifted; water flowed in unexpected ways.

It was an assessment they’d doubled down on in reports to state regulators, despite evidence that the ground had been sinking in some places at a rate of more than one foot a year, fracturing roads and irrigation channels and depleting drinking water stores. Since 2015, Corcoran has experienced nearly 5 feet of subsidence, while areas just outside the town have sunk as much as 6 feet. Before the 2017 emergency work, the 14-mile earthen levee that protects the town had been repaired twice by the U.S. Army Corps of Engineers, in 1969 and 1983.

Now, the state is finally trying to enforce the requirements of a nearly 10-year-old law limiting groundwater pumping that major landowners in a half-dozen regions — including the Tulare Lake Basin — have blatantly resisted. In October, state water regulators announced they’re taking the first step toward putting the Tulare Lake region on “probation” for its lack of progress.