Why I think 3 million acres of irrigated land will go out of production by, say, 2040.

It is my contention that about three million irrigated acres in California will go out of production in the next few decades. My estimate is the highest I have seen.

I break it down as follows: annual overdraft in the SJV is between 4.5-5MAF. When that stops, either because groundwater management agencies bring the basins into balance or because groundwater will drop too low to economically pump, about 1.5M acres will not have irrigation water available to them.

I believe the droughts we are seeing now will be our future normal climate and we will receive very little useable precip. I believe urban users will use political power to claim more of what we do get and to protect adorable fishies. That gets me another million acres.

I believe the Delta will succumb to sea level rise, storm tides and floods on the Sacramento River. That’s another 300,000 acres.

I add these and round up, and arrive at 3 million irrigated acres retired, down from our current 9.5ish million irrigated acres.

Here is Dr. Burt, guessing that 1 to 1.5 million irrigated acres will go out of production. The PPIC/U.C. Davis crew must have a prediction, but I couldn’t find it handily. I’ll put it in this post if someone points me to it.


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4 responses to “Why I think 3 million acres of irrigated land will go out of production by, say, 2040.

  1. Anonymous

    guess we won’t know for another 25 years, but I wouldn’t put my money on any of your calculations. 300,000 acres in the Delta out of production because of sea level rise, storm tides and floods? Don’t count on even 1/30th of that.

  2. Pacific flyway

    Sacramento valley will be fine. The central valley will be solar parks, server farms, high density mixed-use human settlements and, of course, the bullet train.

  3. onthepublicrecord

    I should also have listed habitat restoration.

    See, this is great. Now that I’ve spelled it out, you can disagree with parts and use your assessment of those to evaluate my whole credibility. That’s the benefit of specificity.

    Pacific flyway:
    I think that 3 million acres of ag will remain in the SJ Valley. The independent irrigation districts on the San Joaquin are still pretty water-rich. Some of the Friant will do OK. But we’ll see!

  4. jaylund

    Some back of the envelope calculations seem pretty irresistible. See our Resistance is Futile post on CaliforniaWaterBlog last year. I’d guess for total land going out of production, about 1/2 of urban land expansion in the Central Valley, maybe 100,000-300,000 acres retired from accumulating salinity in the San Joaquin and Tulare basins, maybe 40-100,000 acres in the Delta due to flooding and habitat restoration, maybe as much as 100,000 other acres due to habitat restoration, and 500,000-1.5 million acres lost to lack of water (some of which might be lost to salinity or urbanization anyway). Perhaps, 600,000 – 2 million acres total, or something about this magnitude. Most of this lost farmland will not have the highest value, so economic losses will be much less than proportional. Some of it will become terrestrial habitat. Not all of this will reduce water use (conversions to wetlands or open water, for example). As has occurred throughout history, California and its agriculture will continue to change, becoming a smaller proportion of the state’s economy, and being responding to strong export and domestic markets for its products (as it has since Richard Dana’s time in the 1830s). Still, it seems likely that continued shifts to more profitable crops and better groundwater management will sustain agriculture as a major water user and a profitable base for many rural economies, with the exception of some areas.