A simple instrument with a weight and a pulley confirmed what hydrologist Michelle Sneed had suspected after seeing more and more dirt vanish from the base of her equipment each time she returned to her research site last summer. The tawny San Joaquin Valley earth was sinking a half-inch each month.
The reason was no mystery. “There are wells up and down this road,” Sneed said, nodding toward a two-lane byway that cut across the flat agricultural landscape.
Parts of the San Joaquin Valley are deflating like a tire with a slow leak as growers pull more and more water from the ground. The land subsidence is cracking irrigation canals, buckling roads and permanently depleting storage space in the vast aquifer that underlies California’s heartland.
The overpumping has escalated during the past drought-plagued decade, driving groundwater levels to historic lows in some places. But in a large swath of the valley, growers have been sucking more water from its sands and clays than nature or man puts back for going on a century.
They are eroding their buffer against future droughts and hastening the day, experts warn, when they will be forced to let more than a million acres of cropland turn to dust because they have exhausted their supplies of readily available groundwater…
The Central Valley aquifer extends for about 400 miles under the Sacramento and San Joaquin valleys. The subterranean water, some of which seeped into the ground 10,000 to 20,000 years ago, is California’s biggest reservoir. Yet it has been largely unregulated and unmonitored. Most of the more than 100,000 wells that pierce the valley floor are unmetered and landowners have taken what they wanted.
Scientists estimate that since the first wells were drilled by settlers more than a century ago, pumping has depleted Central Valley groundwater reserves by 125 million acre-feet. That is about 4 1/2 times the capacity of Lake Mead, the biggest surface reservoir in the country. About 20 million acre-feet of that loss occurred in the last decade.
Until last year, California didn’t have a statewide groundwater law, making it an outlier in the West. The legislation, intended to end unsustainable groundwater use, won’t do that any time soon. Agricultural interests opposed the regulations, which call for the creation of local groundwater agencies that have more than two decades to fully comply.
In the meantime, it’s easier for growers to keep pumping than rein in their use. “Telling people they have to stop irrigating is a huge economic thing,” said Charles Burt, chairman of the Irrigation Training and Research Center at Cal Poly San Luis Obispo. “Guys are going to get their guns out…
Read the article for measured, sensible solutions – which, of course, don’t mean a damned thing in American politics. And it will be politics that resolves whatever is implemented in California. Short-term politics, short-term economics, short-term profits – which have always been the bane of Agriculture, whether it’s in the American West growing alfalfa or palm-nuts in Indonesia.
You don’t have to be a cynic to expect that verifiable science means nothing to producers who worry most of all about commodity prices and hedge funds.