A new study 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 study is the first to quantify the amount that groundwater contributes to the water needs of western states. According to the U.S. Bureau of Reclamation, the federal water management agency, the basin has been suffering from prolonged, severe drought since 2000 and has experienced the driest 14-year period in the last hundred years.
The study has been accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union, which posted the manuscript online today.
The research team, led by NASA and University of California, Irvine, scientists, used data from NASA’s Gravity Recovery and Climate Experiment (GRACE) satellite mission to track changes in the mass of the Colorado River Basin, which are related to changes in water amount on and below the surface.
Monthly measurements of the change in water mass from December 2004 to November 2013 revealed the basin lost nearly 53 million acre feet (65 cubic kilometers) of freshwater, almost double the volume of the nation’s largest reservoir, Nevada’s Lake Mead. More than three-quarters of the total — about 41 million acre feet (50 cubic kilometers) — was from groundwater.
“We don’t know exactly how much groundwater we have left, so we don’t know when we’re going to run out,” said Stephanie Castle, a water resources specialist at the University of California, Irvine, and the study’s lead author. “This is a lot of water to lose. We thought that the picture could be pretty bad, but this was shocking.”
Water above ground in the basin’s rivers and lakes is managed by the U.S. Bureau of Reclamation, and its losses are documented. Pumping from underground aquifers is regulated by individual states and is often not well documented.
“There’s only one way to put together a very large-area study like this, and that is with satellites,” said senior author Jay Famiglietti, senior water cycle scientist at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, on leave from UC Irvine, where he is an Earth system science professor. “There’s just not enough information available from well data to put together a consistent, basin-wide picture.”
Famiglietti said GRACE is like having a giant scale in the sky. Within a given region, the change in mass due to rising or falling water reserves influences the strength of the local gravitational attraction. By periodically measuring gravity regionally, GRACE reveals how much a region’s water storage changes over time.
The Colorado River is the only major river in the southwestern United States. Its basin supplies water to about 40 million people in seven states, as well as irrigating roughly four million acres of farmland.
“The Colorado River Basin is the water lifeline of the western United States,” said Famiglietti. “With Lake Mead at its lowest level ever, we wanted to explore whether the basin, like most other regions around the world, was relying on groundwater to make up for the limited surface-water supply. We found a surprisingly high and long-term reliance on groundwater to bridge the gap between supply and demand.”
Famiglietti noted that the rapid depletion rate will compound the problem of short supply by leading to further declines in streamflow in the Colorado River.
“Combined with declining snowpack and population growth, this will likely threaten the long-term ability of the basin to meet its water allocation commitments to the seven basin states and to Mexico,” Famiglietti said.
Coauthors included other scientists from NASA’s Goddard Space Flight Center, Greenbelt, Maryland, and the National Center for Atmospheric Research, Boulder, Colorado. The research was funded by NASA and the University of California.
GRACE is a joint mission with the German Aerospace Center and the German Research Center for Geosciences, in partnership with the University of Texas at Austin. JPL developed the GRACE spacecraft and manages the mission for NASA’s Science Mission Directorate, Washington.
The American Geophysical Union is dedicated to advancing the Earth and space sciences for the benefit of humanity through its scholarly publications, conferences, and outreach programs. AGU is a not-for-profit, professional, scientific organization representing more than 62,000 members in 144 countries. Join our conversation on Facebook, Twitter, YouTube, and other social media channels.
NASA monitors Earth’s vital signs from land, air and space with a fleet of satellites and ambitious airborne and ground-based observation campaigns. NASA develops new ways to observe and study Earth’s interconnected natural systems with long-term data records and computer analysis tools to better see how our planet is changing. The agency shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet. To learn more about NASA’s Earth science activities in 2014, visit: http://www.nasa.gov/earthrightnow.
Notes for Journalists
Journalists and public information officers (PIOs) of educational and scientific institutions who have registered with AGU can download a PDF copy of this accepted article by clicking on this link: http://onlinelibrary.wiley.com/doi/10.1002/2014GL061055/abstract
Or, you may order a copy of the final paper by emailing your request to Peter Weiss at email@example.com. Please provide your name, the name of your publication, and your phone number.
Neither the paper nor this press release is under embargo.
“Groundwater Depletion During Drought Threatens Future Water Security of the Colorado River Basin”
Stephanie L. Castle: UC Center for Hydrologic Modeling, University of California, Irvine, CA, USA; and Department of Earth System Science, University of California, Irvine, CA, USA;
Brian F. Thomas and John T. Reager: UC Center for Hydrologic Modeling, University of California, Irvine, CA, USA; Department of Earth System Science, University of California, Irvine, CA, USA; and NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA.
Matthew Rodell: Hydrological Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA;
Sean C. Swenson: Climate and Global Dynamics Division, National Center for Atmospheric Research, Boulder, CO, USA;
James S. Famiglietti: UC Center for Hydrologic Modeling, University of California, Irvine, CA, USA; Department of Earth System Science, University of California, Irvine, CA, USA; and NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA.
Contact information for the authors:
James Famiglietti: +1 (818) 354-0052, firstname.lastname@example.org
Stephanie Castle: +1 (949) 436-0730, email@example.com
+1 (202) 777-7507
NASA Headquarters Contact:
+1 (202) 358-0918
NASA Jet Propulsion Laboratory Contact:
+1 (818) 354-0474
University of California Irvine Contact:
+1 (949) 824-3969
Peter Weiss | AGU News
NASA sees development of Tropical Storm 11P in Southwestern Pacific
11.02.2016 | NASA/Goddard Space Flight Center
Southwest sliding into a drier climate
11.02.2016 | National Center for Atmospheric Research/University Corporation for Atmospheric Research
Today, plants and microorganisms are heavily used for the production of medicinal products. The production of biopharmaceuticals in plants, also referred to as “Molecular Pharming”, represents a continuously growing field of plant biotechnology. Preferred host organisms include yeast and crop plants, such as maize and potato – plants with high demands. With the help of a special algal strain, the research team of Prof. Ralph Bock at the Max Planck Institute of Molecular Plant Physiology in Potsdam strives to develop a more efficient and resource-saving system for the production of medicines and vaccines. They tested its practicality by synthesizing a component of a potential AIDS vaccine.
The use of plants and microorganisms to produce pharmaceuticals is nothing new. In 1982, bacteria were genetically modified to produce human insulin, a drug...
Atomic clock experts from the Physikalisch-Technische Bundesanstalt (PTB) are the first research group in the world to have built an optical single-ion clock which attains an accuracy which had only been predicted theoretically so far. Their optical ytterbium clock achieved a relative systematic measurement uncertainty of 3 E-18. The results have been published in the current issue of the scientific journal "Physical Review Letters".
Atomic clock experts from the Physikalisch-Technische Bundesanstalt (PTB) are the first research group in the world to have built an optical single-ion clock...
The University of Würzburg has two new space projects in the pipeline which are concerned with the observation of planets and autonomous fault correction aboard satellites. The German Federal Ministry of Economic Affairs and Energy funds the projects with around 1.6 million euros.
Detecting tornadoes that sweep across Mars. Discovering meteors that fall to Earth. Investigating strange lightning that flashes from Earth's atmosphere into...
Physicists from Saarland University and the ESPCI in Paris have shown how liquids on solid surfaces can be made to slide over the surface a bit like a bobsleigh on ice. The key is to apply a coating at the boundary between the liquid and the surface that induces the liquid to slip. This results in an increase in the average flow velocity of the liquid and its throughput. This was demonstrated by studying the behaviour of droplets on surfaces with different coatings as they evolved into the equilibrium state. The results could prove useful in optimizing industrial processes, such as the extrusion of plastics.
The study has been published in the respected academic journal PNAS (Proceedings of the National Academy of Sciences of the United States of America).
Exceeding critical temperature limits in the Southern Ocean may cause the collapse of ice sheets and a sharp rise in sea levels
A future warming of the Southern Ocean caused by rising greenhouse gas concentrations in the atmosphere may severely disrupt the stability of the West...
09.02.2016 | Event News
02.02.2016 | Event News
26.01.2016 | Event News
11.02.2016 | Life Sciences
11.02.2016 | Physics and Astronomy
11.02.2016 | Earth Sciences