Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How climate change will affect western groundwater

18.02.2016

By 2050 climate change will increase the groundwater deficit even more for four economically important aquifers in the western U.S., reports a University of Arizona-led team of scientists.

The new report is the first to integrate scientists' knowledge about groundwater in the U.S. West with scientific models that show how climate change will affect the region.


Water can reach and recharge a groundwater aquifer various ways. Precipitation can percolate directly into the aquifer; water from streams and runoff can percolate into the aquifer; water from irrigating crops can percolate deep into the soil; and water from melting snowpack and from mountain streams can flow into the valley below and then percolate into the aquifer.

Image courtesy of David Stonestrom, U.S. Geological Survey

"We wanted to know, 'What are the expectations for increases and decreases in groundwater as we go forward in this century?'" said lead author Thomas Meixner, a UA professor and associate department head of hydrology and water resources. "In the West, 40 percent of the water comes directly from groundwater."

Climate models predict that in general, wet regions will become wetter and dry regions will become drier. The Southwest is expected to become drier and hotter.

"Aquifers in the southern tier of the West are all expected to see slight-to-significant decreases in recharge as the climate warms," Meixner said.

Groundwater is already being withdrawn from the aquifers of California's Central Valley, the central and southern portions of the High Plains and Arizona's San Pedro faster than the groundwater is being recharged.

Climate change will make the groundwater deficits worse in those aquifers, the researchers report.

For the Death Valley and Wasatch Front aquifers, the effect of climate change on the balance between usage and recharge isn't so predictable.

In contrast, western aquifers at about the latitude of Boulder, Colorado and further north are likely to be recharged faster than people withdraw the water, the team reports. The northern aquifers the researchers studied are the northern High Plains, the Spokane Valley, the Williston Basin and the Columbia plateau.

"In the long term, pumping has to equal recharge. You can get there through slow social adjustment. You could slowly decrease water withdrawal by conservation and efficiency," Meixner said. "Or you can hit bottom and have farm abandonment and dry wells."

"It's a social decision as to who gets the water," Meixner said. "The southern regions of the western U.S. must be prepared to adapt to a much drier future."

The team's research article, "Implications of projected climate change for groundwater recharge in the western United States," is now online and is scheduled for publication in the March issue of the Journal of Hydrology. UA Associate Professor of Atmospheric Sciences Christopher Castro is a co-author. A list of all seventeen authors is at the bottom of this release.

The report is an outgrowth of a workshop held at the U.S. Geological Survey's John Wesley Powell Center for Analysis and Synthesis. The National Science Foundation and USGS funded the workshop.

To synthesize existing knowledge and predict how climate change would affect western groundwater, Meixner gathered 16 experts in climate change and in hydrology of the western U.S.

Predictions at the major river basin or several-state level can be useful for developing water policy, the team wrote. However, the team found predictions from existing studies were either at a global scale or at the local level, not at the regional level.

To create regional-scale predications, the scientists synthesized existing studies and applied current knowledge of recharge processes. The team studied eight economically important western aquifers for which studies about their groundwater recharge budgets existed. In addition, models of how climate change would affect recharge were available for four of the aquifers.

To compare all eight aquifers, the team developed a uniform classification scheme for the components of groundwater recharge. The scientists identified four different components of groundwater recharge: diffuse, focused, irrigation and mountain system.

Some types of recharge are more easily affected by human behavior and water policy than others. Human decision-making can easily affect irrigation recharge, water that percolates deep into the soil from irrigating crops, and focused recharge, water that reaches the groundwater from streams or runoff.

In contrast, human behavior has a much smaller effect on diffuse and mountain-systems recharge. Diffuse recharge comes from the precipitation that falls on a specific spot and then percolates down into the groundwater.

Much of the mountain-systems recharge comes from snowpack, Meixner said. As the snow melts, the water fills mountain streams which end up in the flatlands below. Snowmelt can also percolate into the soil and eventually reach the valley below as the water moves downhill through the bedrock underlying the mountains.

The San Pedro aquifer in southeastern Arizona is one example of an aquifer where the human use of groundwater will increasingly outstrip recharge as the climate warms, the researchers report. Much of the San Pedro's current recharge comes from mountain-system recharge, which the scientists expect will dwindle as more precipitation falls in the mountains as rain rather than snow and as the region dries.

When more groundwater is pumped than is replaced by recharge, rivers can be sucked dry, as happened to the Santa Cruz River in Tucson, Meixner said. Once the Santa Cruz flowed year-round; now in Tucson the river has water only after heavy rains.

"What you would expect to see is that climate change will exacerbate problems in the Southwest on the recharge end," Meixner said.

"Our study reveals that the western U.S. needs to redouble efforts to manage water resources to maximize benefits to individuals and society," he said. "We can't be wasting water."

###

Author list for "Implications of projected climate change for groundwater recharge in the western United States."

Thomas Meixner, University of Arizona, Tucson; Andrew H. Manning, U.S. Geological Survey, Denver; David A. Stonestrom, USGS Menlo Park, California; Diana M. Allen, Simon Fraser University, Burnaby, British Columbia, Canada; Hoori Ajami, University of New South Wales, Sydney, Australia; Kyle W. Blasch, USGS, Boise, Idaho; Andrea E. Brookfield, Kansas Geological Survey, Lawrence; Christopher L. Castro,University of Arizona; Jordan F. Clark, University of California, Santa Barbara; David J. Gochis, National Center for Atmospheric Research, Boulder, Colorado; Alan L. Flint USGS, Sacramento, California; Kirstin L. Neff and Rewati Niraula, University of Arizona; Matthew Rodell, NASA Goddard Space Flight Center, Greenbelt, Maryland; Bridget R. Scanlon, University of Texas, Austin; Kamini Singha, Colorado School of Mines, Golden; Michelle A. Walvoord USGS, Denver.

Related websites:

Thomas Meixner
http://www.hwr.arizona.edu/users/tmeixner

USGS John Wesley Powell Center for Analysis and Synthesis
https://powellcenter.usgs.gov/

Researcher contact:

Thomas Meixner
520-626-1532
tmeixner@email.arizona.edu

Media contact:

Mari N. Jensen
520-626-9635
mnjensen@email.arizona.edu

http://uanews.org 

Mari N. Jensen | EurekAlert!

Further reports about: Geological Survey groundwater recharge water resources

More articles from Earth Sciences:

nachricht Devils Hole: Ancient Traces of Climate History
24.05.2017 | Universität Innsbruck

nachricht Supercomputing helps researchers understand Earth's interior
23.05.2017 | University of Illinois College of Liberal Arts & Sciences

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

Physicists discover mechanism behind granular capillary effect

24.05.2017 | Physics and Astronomy

Measured for the first time: Direction of light waves changed by quantum effect

24.05.2017 | Physics and Astronomy

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>