DEEP BENEATH the bleached-out, dusty surface of the drought-stricken West is a stash of water sequestered between layers of rock and sometimes built up over centuries.
Officials in the Colorado River basin states have long treated this liquid treasure as a type of environmental retirement account — an additional supply of water they can raid to get through the driest years and make up for the chronic overuse of the rivers themselves.
In recent years, the withdrawals have taken on even more importance: At least 60 percent of California’s water now comes from underground, some researchers say. Arizona, staring down imminent rationing of Colorado River water, pumps nearly half its supply from aquifers.
But in allowing their residents to tap underground resources this way, regulators and legislators in Southwestern states have ignored an inconvenient truth about how much water is actually available for people to use: In many places, groundwater and surface water are not independent supplies at all. Rather, they are interconnected parts of the same system.
The science has been clear for the better part of a century. Drawing groundwater from near a stream can suck that stream dry. In turn, using all the water in streams and rivers lessens their ability to replenish the aquifers beneath them. Farmers who drill new wells to supplement their supplies with groundwater are often stealing water from their neighbors who hold rights to the rivers above them. This understanding has been the foundation of the U.S. Department of the Interior’s water accounting for decades, and was used by the U.S. Supreme Court to decide one of the most significant water contests in history.
Yet California and Arizona — the two states water experts say are facing the most severe water crises — continue to count and regulate groundwater and surface water as if they were entirely separate.
“States have their own take on this. Or they choose to not address it at all,” said Stanley Leake, a hydrologist with the U.S. Geological Survey and a leading expert on properly accounting for the connection between ground and surface waters in the West. “In some cases they pretend that there is no connection.”
Leaders in California and Arizona acknowledge that their states have done this, at least in part to avoid the grim reckoning that emanates from doing the math accurately. There is even less water available than residents have been led to believe.
If these states stopped effectively double-counting their resources, they would have to change laws, upend traditional water rights and likely force farmers and cities to accept even more dramatic cuts than they already face — a political third rail.
“The politics of water are more challenging than any other issue the state faces,” said Fran Pavley, a California state senator who helped draft a much-praised package of state laws passed last year regulating groundwater withdrawals for the first time.
Tucked into Pavley’s package was a little-noticed provision that explicitly prohibits California state regulators from addressing the interconnection between groundwater and surface water in local water plans until 2025, a compromise meant to give local water agencies a leisurely runway to adjust to a new way of counting.
Pavley said the prospect of more immediately acknowledging the overlap between ground and surface waters threatened to derail the legislation entirely, triggering fierce opposition from the Agricultural Council of California, the California Chamber of Commerce and other industry groups.
“Those who have unlimited water supply don’t particularly like the idea of changing that,” she said. “You can’t manage what you don’t measure.”
Arizona law, too, treats groundwater and surface water as unconnected, as does Arizona’s state water plan, which purports to account for water resources and to estimate how many years of supply remain. Its authors know better, Arizona’s top water official acknowledged, but rewriting them to be more truthful would be politically impossible and economically damaging.
“We know for a fact that pumping aquifers can dry up rivers,” said Thomas Buschatzke, the director of the Arizona Department of Water Resources, who says his policy is bound by the Legislature and court rulings. “But it is the law … it would be a huge upset to the economy to do away with that.” . . .
Denial is a primitive but very strong response to problems. In this situation, denial means that when states eventually have no choice but to face reality they will be in a much worse position to find solutions. The “huge upset to the economy” that truthful and accurate reporting of reserves would cause is nothing to the upset that will occur when the West truly does hit the brick wall and run out of water. But better not to think about that, yes? Just let it happen…