Gravity Satellites Show a Huge Groundwater Loss in California

By Andrew Moseman | December 16, 2009 12:37 pm

CaliforniaSat220Groundwater levels around the country have been sinking as wells for drinking water and irrigation pull water out of aquifers faster than they can naturally recharge. Now, using gravity-measuring satellites, NASA and California researchers have documented the extent of water loss in California’s Central Valley, and the results aren’t good.

The measurements show the amount of water lost in the two main Central Valley river basins within the past six years could almost fill the nation’s largest reservoir, Lake Mead in Nevada [AP]. The total is about 30 cubic kilometer; one cubic km contains more than 264 billion gallons of water.

The team used the GRACE satellites to measure tiny fluctuations in the planet’s gravitational field. Researchers have used these satellites to track changes in ice sheets, but turning these orbiters on California allowed them to see how much the pull on the planet had lessened there, and thus how much water had been lost from the ground.

The satellites can detect changes in the amount of water in a region but not how much is left. Regardless of how much water remains in the aquifer, the researchers note that a declining water table will degrade water quality and will eventually force Californians to drill deeper wells [Science News]. That’s bad news not just for Californians: the Central Valley accounts for an estimated one-twelfth of the nation’s agricultural production.

“The numbers we’re getting out of this analysis point to groundwater use at unsustainable rates,” said Professor Jay Famiglietti of the University of California, Irvine. “It’s leading to declining water tables, decreased crop sizes, and continued land subsidence – something that has been going on in the Central Valley for decades” [BBC News].

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Image: NASA

CATEGORIZED UNDER: Environment, Technology
  • badnicolez

    Shouldn’t those reservoirs start refilling now that water has been cut off from large areas of the Central Valley…or will the farmers use more groundwater from wells now?

  • rabidmob

    Do you mean the man made reservoirs?

  • Fatkid

    If we paid now for the resources used to put that burger and fries on the table, I wouldn’t be so fat! Who has twenty dollars for a hamburger?

  • lyllyth

    It would be way nice if those farmers would start using drip irrigation instead of broadcasting sprinklers, where like, 70% of the water evaporates rather than going to the crops.

    But you know, they like, totally stole the Colorado River fair and square for their Aqueduct in the first place, right?

    Who cares how they use it, or that it no longer reaches its delta, or that the whole ecosystem that used to live there has been permanently extinct since the Aqueduct’s inception.

    Great Public Works!

  • torres

    Who the hell wrote this? “The team used the GRACE satellites to measure tiny fluctuations in the planet’s gravitational field. Researchers often use them(WHAT?) to track changes in ice sheets, but this(?) turning these orbiters on California allowed them to see the(?) how much the pull on the planet had lessened there, and thus how much water had been lost from the ground.” I get what you are saying, but take the time to write more clearly.

  • Bill J

    We definately should try to understand the gravity of the situation!!

  • Doug Nusbaum

    Here is a test for you liberals out there. And most scientists are liberals. Make a list of really serious problems. Rank order them. Now point to ones that do not have some massive government program as their origin.

    How much different would our entire ecology be if the government had not built all those (free) highways and super-highways so that we could have a great spread out culture not amenable to mass transit — mass transit that the subsidized (via free highways) automobile companies help destroy.

    Now we have all those government water programs. That is working out well in the long run.

  • Randee

    Idiots, using up the earth’s resources is not a right or left political concept… and it’s good thing most scientists are liberal, that leaves you ‘less-intelligents’ to do politics & religion.

  • Eliza Strickland


    Yep, there were a couple of typos in that sentence. Thanks for catching them — I’ll fix them now.

  • wcfloyd

    Oh No!!! California now has a gravity shortage! Wait til National Enquirer, Sac Bee & Mercury get hold of this! :-)

  • draftedin68

    Rice, rice, rice!

    I live in a part of California that is literally afloat in rice fields.

    The acreage now used for rice was greatly increased a few years ago due to repeated droughts in S.E. Asia.

    The sad facts are that even though rice is a HUGE water waster, most all of the rice is exported, the rice is federally price-supported and the water is subsidized.

    Two years ago, our naturally soft water (from wells) began to reek.

    I know – just a coincidence.

  • frank

    Seems like we always take a scientific fact and try to make a political point of view known. Scientists try to do things to correct problems and to make the existence of man on this planet better. Maybe we need to recognize that as the earth changes we must change to accomodate it or we will ruin it.

  • Marguerite Capp

    Since when does Colorado River water end up in the Central Valley? The Colorado River is used in Las Vegas and Los Angeles!!!! The farmers in the Central Valley get their water from the Sacramento River, the San Joaquin River, and the Tulare Lake when it overflows. If you want to give someone a bad time, give those folks in Vegas and LA a bad time about their swimming pools! And if you want to eat fruit and veges in the future, then you’d better support those farmers instead of the urbanites. Building huge houses in areas which go completely dry for 8 to 10 months out of the year is a really stupid idea.

  • critters

    Something you all seem to be missing or forgetting is that ALL of California have suffered serious droughts in recent years. It is not just rain that falls in the valleys that provides groundwater. Summer melt from the snow in the mountains is the main contributor to water for the valleys. Currently, the snowpack is above average for water content in the Sierras, however, it is not even close to replenishing California’s water supply. We need several years of better than average snowfall to recover.

    We must adapt to the changing climate. Unfortunately, the problem is not as simple to solve as raising the price of a hamburger or reducing the number of rice fields. Waste of water is widespread and the solution comes down to each individual being responsible for wise usage of this precious resource.

    I’ve seen horrible wastage of water in the cities of CA. Lawns of businesses and homes are green and watered to the point of being sloppy-wet even in the late summer and early fall when water levels are the lowest. Despite decades of metering water, too many people still insist on washing their cars every weekend and not using low flow shower heads and think that all they have to worry about is a higher water bill at the end of the month.

    Those of us on California farms and ranches that have to pull our water from wells (and even rivers and canals) let our lawns go dry, take sponge baths instead of showers, and if it’s yellow, let it mellow EVERY summer so that we have enough water to drink, and to be able to water the livestock for your hamburgers, grow the hay to feed those hamburgers (and your horses), and grow the grain that you eat in your bowl of healthy, organic cereal every morning. Our vehicles get washed in the winter rains and snows. For us, it’s not a matter of a higher water bill at the end of the month, it’s a matter of having any water at all when we turn on the faucet. And yes, there are still those farms and ranches that waste water. But we ALL have to be responsible for our water usage.

  • Carolyn

    Marguerite is absolutely correct. There are a lot more rivers than those she named but none of them is the Colorado. The water supplies in the San Joaquin Valley (and the foothills, where I live) come from rivers sourced by snow melt. Not all of the water loss comes from usage in the Valley, either. The California Aqueduct funnels a lot of it to LA.

  • Mike

    Come on people…don’t dump all your hate on LA. Places like Atlanta are just as bad if not worse, and they were really hurting in their recent drought. Also, cities like San Antonio are suing places like Austin, trying to get to their water supplies, currently Austin’s reservoirs are very low. There are endless suburbs in those areas too with huge, wasteful green lawns. Don’t forget the pools in Phoenix or Vegas…

    Things are changing in LA…more and more lawns are being landscaped with succulents native pants and rock gardens as well as giving up grass space. In fact, so much water use has decreased that old water pipes all over the city are bursting because they can’t handle the pressure.

  • john raguso

    I guess we’ll have to wait until there is a water shortage disaster— people starting to die in the streets— before something begins to be done.

  • Dorian

    They’re not detecting water loss from aquifers, they’re detecting Californians migrating to Washington.



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