Southern California and the neighboring Southwestern states have been overallocating water from the Colorado River for decades. And the day of reckoning for such an unsustainable approach to water management has finally arrived (see this month’s article on the Colorado River).
But there’s another seemingly endless supply that Californians have drawing down for more than a century — the aquifer underlying the San Joaquin Valley from Kern to Merced Counties(1). Reality, however delayed in its acknowledgement, finally intervened. After decades of delay, in 2014 the California legislature passed the Sustainable Groundwater Management Act (SGMA), requiring overlying groundwater pumpers in significantly overdrafted basins to bring their groundwater basins into balance (the standard is avoid “undesirable” results).
With two or three million acre-feet of average annual “overdraft,” that job is just as hard as bringing California’s Colorado River overuse into balance. Unfortunately, an unintended consequence of passing SGMA has been to motivate some water users to divert even more water from already overallocated surface water systems – rivers and streams, that is – in order to make up for their over-extraction of groundwater…