Subscribe free to our newsletters via your
. Earth Science News .


Subscribe free to our newsletters via your




















WATER WORLD
How climate change will affect western groundwater
by Staff Writers
Tucson AZ (SPX) Feb 18, 2016


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. For a larger version of this image please go here.

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.

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Groundwater is already being withdrawn from the aquifers of California's Central Valley, the central and southern portions of the High Plains and Arizona's San Pedro faster than the groundwater is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

.


Related Links
University of Arizona
Water News - Science, Technology and Politics






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
WATER WORLD
Beavers bring environmental benefits
Stirling, UK (SPX) Feb 17, 2016
Beavers are beneficial to the Scottish environment, say academics from The University of Stirling. A study into the ecology and habitat engineering of beavers reintroduced to a site on Tayside in 2002 has found the creatures can improve biodiversity, minimise pollutants and reduce downstream flooding. Examining head water streams which drain water from 13 hectares of Scottish countryside, ... read more


WATER WORLD
Turkish warplanes enter Greek airspace ahead of NATO migration operation

Australian hospital refuses to return asylum baby to Nauru

Erdogan threatens to send refugees to EU as NATO steps in

Characterizing the smell of death may help rescue workers at disaster sites

WATER WORLD
Body temperature triggers newly developed polymer to change shape

Light used to measure the 'big stretch' in spider silk proteins

Making sense of metallic glass

Not your grandfather's house, but maybe it should be

WATER WORLD
Rising Seas Slowed by Increasing Water on Land

Southwest sliding into a drier climate

Study finds fish larvae are better off in groups

Testing detects algal toxins in Alaska marine mammals

WATER WORLD
Ice sheet modeling of Greenland, Antarctica helps predict sea-level rise

150,000 Antarctica penguins die after iceberg grounding: study

Clams help date duration of ancient methane seeps in the Arctic

Penguin parents: Inability to share roles increases their vulnerability to climate change

WATER WORLD
Kansas State University researchers staying ahead of wheat blast disease

DNA rice breakthrough raises 'green revolution' hopes

Enhanced levels of carbon dioxide are likely cause of global dryland greening

Livestock donations to Zambian households yield higher income, improved diet

WATER WORLD
5.8-magnitude quake hits New Zealand city: USGS

Tragic tales of loss in Taiwan as search for quake survivors ends

New app turns smartphones into worldwide seismic network

One dead in Portugal floods as cyclist swept away

WATER WORLD
It takes more than a village to build a house

DR Congo announces ivory trafficking arrests

Gloom hangs over African mining as China growth slows

Sudan names new military chief amid Darfur clashes: ministry

WATER WORLD
Easter Island not destroyed by war, analysis of 'spear points' shows

South Africa's Sterkfontein Caves produce 2 new hominin fossils

Neanderthal DNA has subtle but significant impact on human traits

Light and manganese to discover the source of submerged Roman marble




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News








The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.