Earth Matters

Goodbye Groundwater: GPS and Satellites Reveal an Oft-Unseen Aspect of Drought

September 26th, 2014 by Kathryn Hansen

Science Cover_GRACE

Drought-induced depletion of groundwater is no longer an issue that’s out of sight, out of mind.

Research by scientists from Scripps Institution of Oceanography, published this week in Science, describes a GPS technique used to measure drought-induced uplift of land in the western United States. The uplift measurements were used, in turn, to calculate the deficit in surface and near-surface water for the area, which they estimated for March 2014 to be 240 billion tons. That’s equivalent to a 4-inch-thick layer (10 centimeters) of water over the region, or the current annual mass loss from the Greenland Ice Sheet.

GPS is not the only way to measure land displacement caused by the loss of ground and surface water. Scientists have long used the Gravity Recovery and Climate Experiment (GRACE) satellites to estimate groundwater depletion around the planet, as noted by Marcia McNutt in a related editorial.

GRACE’s achievements even graced the cover of the same issue of Science (pictured above). The image shows California’s loss of fresh water (red) from 2002 through 2014. Drought has drained the region of more than 3.6 cubic miles (15 cubic kilometers) of fresh water in each of the past three years.

The image was updated from a version that initially appeared alongside research in 2013 by James Famiglietti of NASA’s Jet Propulsion Laboratory and University of California, Irvine, and Matthew Rodell of NASA’s Goddard Space Flight Center.

Read more to learn about how GRACE is used to view Earth’s water supplies, or how U.S. groundwater on July 7, 2014, compared to the average from 1948 to 2009.

8 Responses to “Goodbye Groundwater: GPS and Satellites Reveal an Oft-Unseen Aspect of Drought”

  1. Fern Henley says:

    North America Water and Power Alliance (NAWAPA) was placed in the minds of citizens by John F Kennedy and the Parsons engineering firm 50 years ago to meet the challenge of drought and related conditions. To survive we must quickly initiate this program as well as other rain enhancement systems available.
    As planet Earthchanges made human life possible we now have reached an impasse in which planet is becoming uninhabitable if terraforming is allowed to continue without human intervention. What an exciting challenge!

    • horst obrien says:

      what I don’t understand is that we don’t build salt water conversion plants!

      • derrick says:


      • Sunwyn Ravenwood says:

        Horst, there are desalination plants but they are expensive to build and run, they use a lot of energy, the water they produce is more expensive than groundwater or river water, and they produce a large quantity of toxic brine. Removing the salt from the water doesn’t make it disappear, it just concentrates the salt in the remaining water. This is easy to discharge from a ship, but a stationary plant which sends the brine back into the sea must be discharged through a long pipe to get it away from the coast, and where it is discharged the toxic brine spreads out, killing everything around it.

      • Nancy says:

        In countries like the US, with heretofore abundant water supplies, the energy cost is prohibitive. As climate change progresses, this equation may start to balance out.

  2. Hela Kochbati says:

    Hello dear all,

    It will be nice to export this study to the region of North Africa with your expertise and our national specialists.

    Thanks and Best regards.

  3. Sandra Carolan says:

    I’m searching for the correct audience to expand the use of Energy passive Groundwater Recharge Product (EGRP) that was invented in Michigan. Parjana needs research partners to validate the quantity of recharge for this negative pressure system (based on the human body) that was invented to waterproof a residential home. It works on gravity, vacuum and hydrostatic pressure; and requires no maintenance.
    This is GOOD news coming out of DETROIT. Please ask for Sandra if you can provide appropriate contacts that can be a catalyst for implementation; and PI’s who would be interested in research partnerships as multiple applications are pursued.
    I would like to see pilot project areas where recharge can be measured (perhaps by GRACE), with the data published so that this Green Infrastructure technology can be implemented on a wider scale in areas of concern. The numerous benefits of handling storm water naturally on site begin with energy use reduction, runoff mitigation, groundwater recharge and water and soil quality improvement, but have a much wider application. We have installers in MI, CA, and the UK with over 150 effective installations commercially.

  4. dolores lorez johannes gregory says:

    gracias que pasen un buen dia