28 Jul 2014

Your groundwater accountant is calling

Six months ago, I suggested a few ways to deal with the drought in the western US. Besides raising prices to reduce demand -- my first suggestion, always -- I mentioned that California needed to end unsustainable groundwater pumping ("overdrafting") by farmers.*

I and others have called for better controls on groundwater since at least 2009. In that same year, Tim Quinn (head of ACWA, which represents big water agencies and many irrigation organizations) estimated that overdrafting would increase from the "normal" rate of 2 million acre feet (California gets 40MAF per year) to 4 MAF, so we're talking from bad to worse.

How are farmers responding to this existential threat? In 2008, the California Farm Bureau said:**
We encourage landowners in critically overdrafted areas to continue to devise and implement, under local control, groundwater management plans. We believe that local control over groundwater management is best accomplished through existing water entities or new water entities formed by local landowners for the purpose of groundwater management.
That policy position, as I predicted in a 2009 post ("Chronicle of a Death Foretold") has failed, as we see from this recent update:
A new study by University of California, Irvine and NASA scientists finds more than 75 percent of the water loss in the drought-stricken Colorado River Basin since late 2004 came from underground resources. The extent of groundwater loss may pose a greater threat to the water supply of the western United States than previously thought.
This story is based on the GRACE project led by Jay Famgletti at UC Irvine,*** which continues to reveal how deep a hole we've dug for ourselves. farmers have dug for themselves. GRACE data say that 75 percent of the 51MAF overconsumption of water has come from groundwater, i.e., 41 MAF in the last ten years.

Those numbers refer to the southern Colorado River Basin, not California. They are probably representative and may even be better less worse than California's numbers.

Why do we care? Groundwater helps in drought because we can draw on multiple years of storage when surface water flows and storage are below trend. That "dry-day fund" has allowed many people to ignore the current drought and helped farmers make money without surface water deliveries, but it's going fast and it's VERY HARD to replace.

Bottom Line: Groundwater depletion is a precondition for environmental collapse, economic disruption and outbound migration. Plan accordingly.

* I repeated that advice two weeks ago at my Reddit AMA.
** I'm quoting from the blog post, but the source -- CFBF's "policy guide" -- is NOT posted online
*** Read this great interview with Jay. Then pack your bags to leave California.

H/Ts to DPG and RM


daniel said...

Sad that I missed your AMA, seems it had some great questions/answers. Keep it up!

Frogasaurus Rex said...

It's often not productive to point fingers and play the blame game. How about offering solutions instead of telling people they are bad for doing what they know how to do.

Change comes when people realize there is a better way. But when they are told they are bad it's harder to look at new solutions.

David Zetland said...

@Frogasaurus -- I've said *many times* what to do, but you're right that it bears repeating:
(1) Establish "sustainable" withdrawal limits for each aquifer. These can be as simple as "the wellhead will not drop, on average, each year"
(2) Monitor g/w use for all
(3) Allow users to trade 10-25% of their permitted withdrawal, to increase flexibility without overwhelming local hydrology.

I'll note that some California aquifers are sustainably managed by individuals or groups. Management is better is most western states.

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