The NY Times story on the 05 June 15 business page opened a whole new chapter in the book of California groundwater managment stupidity (oxymoron alert). Upstream newcomers can drill like crazy near rivers and reservoirs to lower them before the water can go into irrigation canal intakes going to senior water right holders. Even better, pump so hard that ground subsidence will lower the canal so much that water no longer will flow down it.
This is a great example of laissez-faire capitalism desperately needing a government nanny to step in and regulate the bejezus out of the private sector before it destroys itself along with the state’s groundwater resource. California passed some voluntary regulations (oxymoron alert) last year but the rules don’t kick in for 25 years. An estimated ~20 years of groundwater are left.
This is straight out of Garrett Hardin’s 1968 classic ‘Tragedy of the Commons’,
http://www.sciencemag.org/content/162/3859/1243.fullThe dueling water users depicted here are a struggling almond grower from Punjab ($383,987 in EWG cotton subsidies, $14 million annual sales, $8 million 2nd home in Pebble Beach) and a family alfalfa farm ($11,522,057 in USDA subsidies, $3.7 million annual profit on $25 sales) with the ultimate senior water rights.
Here you can look up individual farm gov’t subsidies in the Environmental Working Group data base,
http://farm.ewg.org/. It is not clear where the public benefit derives when 80% of almonds and alfalfa are exported to Asia. Trickle-down?
It is not clear how more urban sacrifice -- sponge baths, landscaping ripped out — will change what these farmers know full well is a race to the bottom: reckless and irreversible depletion of groundwater. It reminds me more of massive food exports to England during the height of the Irish Potato Famine — only with water.
The Times had a rosy quote about subsidence reversibility from USGS hydrologist and INSAR expert Michelle Sneed. Not believing Sneed was a denier, I chased down her scientific publications, soon finding she had said the exact opposite: "As groundwater levels drop, clay deposits move closer together and space for groundwater is lost. You can never get the deposits to go back."
http://pubs.usgs.gov/sir/2013/5142It all depends on the basin; CA has some 575 of them with varying degrees of characterization. The situation here is a water table perched over Corcoran clay. Shallow wells (remember them?) access that groundwater. These can be replenished by irrigation with surface water, the more wasteful the better, if you don’t mind a whole lot of selenium, sea salt and farm chemicals.
Deeper wells access a second pool of deeper groundwater, not an underground lake but rather water filling pores in silt and clay. [This is the exact opposite of Glen Canyon dam where the Navajo sandstone pores are being massively and irreversibly hydrated.] Once removed, the weight of ground overhead causes pore compaction.
The resulting subsidence — an astonishing half meter per year in places -- is irreversible: the groundwater reservoir cannot be renewed by pumping or infiltration, it has been strip-mined by one generation of unsustainable agriculture.
The Times ran a most excellent map of regional subsidence. USGS provides extensive resources explaining how the map was made from satellite insar; we use interferometry quite a bit on the Greenland forum for ice sheet velocity and thinning. See methodology section of
http://pubs.usgs.gov/sir/2007/5251/index.htmlThe article offers a great quote from “Mr.” Famiglietti (a Princeton Ph.D in engineering and full professor, not worthy of the same respect as the Times’ Dr. Kissinger):
“California passed stronger regulations last year but the rules won’t have any real effect for 25 years or more, says Jay Famiglietti, senior water scientist at the NASA JPL. “You drill a well on your property, you draw it out, even if it means you draw from under your neighbor’s property,” he says. “You’re drawing water from every direction.” In a normal year, Mr. Famiglietti says, 33 percent of California’s water comes from underground, but this year it is expected to approach 75 percent. Since 2011, he says, the state has lost eight trillion gallons from its overall water reserves, two-thirds of that from its underground aquifers.
We can’t keep doing this,” Mr. Famiglietti says.
http://www.nytimes.com/2015/06/07/business/energy-environment/california-farmers-dig-deeper-for-water-sipping-their-neighbors-dry.html
