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The 60 Million Acre-Foot Hole - A Memorable Moment from the California Assembly Groundwater Hearing

Barry Nelson

Posted February 2, 2011

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If I had to pick one moment from yesterday’s excellent Assembly oversight hearing on groundwater, it would be when Dave Orth, from the Kings River Conservation District, showed this graphic to the committee.

Change in GW Storage Graphic.png












It’s from a 2009 USGS report  and shows that the cumulative overdraft in the Tulare Basin since 1960 is greater than 60 million acre-feet. That is a staggering number! If we were to try to fill that hole with Delta water alone, it would take more than a decade of CVP and SWP pumping at current rates. (That would mean no Delta water for Westlands, the exchange contractors, Silicon Valley, Southern California and others. I suspect that they would object.) And that’s assuming that Tulare Basin farmers stopped using SWP water to irrigate their crops – but devoted all of that water to groundwater recharge instead. Clearly, the solution to this problem is long-term management.

The take-away message was clear -- the greatest overdraft problem in California is in the Southern Central Valley. Interestingly, that’s also where some of the state’s worst groundwater contamination is located.    

There’s an irony here – the greatest resistance to state-wide groundwater management has traditionally come from agriculture. Yet this graphic shows that agriculture has the most to lose if we don’t make more progress toward a coherent management system. That’s why the Kings River Conservation District is working to improve groundwater management. In fact, in agriculture today, there’s a groundswell of recognition of the need to make dramatically greater progress in this arena.  

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Ray WalkerFeb 3 2011 07:59 PM

Irony ... you got to love it ...

CA has long since been offered a totally NEW fresh water Source of a million acre feet EACH YEAR. US Guess ( fondly USGS ) estimates are very close to the same number ...

How CA can ignore a free confidential disclosure of such a vast natural resource that has been guaranteed not to damage the environment or the water rights of others is ...cough ... irresponsible.

To add insult to injury, CA could utilize the air space in Lake Mead to accumulate surplus and contribute to a 2000 megawatt renewable energy source ( $1 Billion/year) in a facility that is already constructed,bought and paid for, but that would require communication/coordination with the Bureau of Reclamation which has no interest in being creative either.

Considering the risk ( zero - its free info) to reward, one can only wish in one hand (and watch aquifer depletion in the other) that CA will take a tiny step forward to avoid the same quagmire ( groundwater depletion) that took down the South Platte, Arkansas and Rio Grande Rivers in the same last 60 years!

Who cares ... ?
Retired Water Rights Analyst

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