Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Past droughts geographically widespread in the West, according to tree-ring data

19.08.2005


When it’s dry, it’s dry all over, according to a new analysis of more than 400 years of annual streamflow in the Upper Colorado and Salt and Verde river basins.



By using data from tree rings, University of Arizona researchers conclude that water supply for those western rivers fluctuated in synchrony during periods of severe drought. The study goes back almost 800 years in the Salt-Verde basin and covers waterways from the states of Arizona, Colorado, New Mexico, Utah and Wyoming.

The project’s overall conclusion is that severe droughts and low-flow conditions in one basin are unlikely to be offset by abundant streamflow in the other basin.


"Prior to the findings from this study, the conventional wisdom was that runoff from the Colorado River would be available to make up for deficits on the Salt and Verde rivers during times of extreme drought," said Charlie Ester, Salt River Project’s manager of Water Resource Operations. "The bottom line is that the Upper Colorado Basin and the Salt and Verde basins work together as one entire region."

Tree-ring-based reconstructions of streamflow can peer back into time much further than the records available from stream-flow gauges. Ester said such reconstructions could provide important insights into the hydrologic variability of a river basin over time.

The findings represent just the first phase of a study partnered by SRP and The University of Arizona’s Laboratory of Tree-Ring Research. UA scientists Katherine K. Hirschboeck, an associate professor of climatology, and David M. Meko, an associate research professor, conducted the tree-ring analysis.

The study’s second phase, which will begin this month, will take a closer look at more recent history when scientists from the tree-ring lab will re-core trees in the Salt and Verde watersheds to gather new data from the last 40 years, a period when the watersheds have experienced both record wet and record dry episodes. The findings of the second phase will likely be available in the summer of 2007.

Key project conclusions from the tree-ring study:

  • Extreme events, either low flows or high flows, tended to occur simultaneously in the Upper Colorado and Salt/Verde river basins;
  • Such synchronous low-flow and high-flow events tended to cluster in time;
  • The longest continuous period when both basins had extreme low-flow years was three years;
  • Within any four-year period, having either high flow or low flow for two consecutive years occurred more than 20 percent of the time;
  • For the Salt/Verde river basin, the recent drought is similar to that experienced in the 1950s;
  • The tree-ring record reveals that between 1200 and 1903, the Salt/Verde river basin had at least eight droughts as severe as the 1950s drought.

Ester said the findings will help devise an assessment tool for implementing the project’s results into operational water supply decision-making.

Hirschboeck said the study’s findings offered some revelations for the Laboratory of Tree-Ring Research’s scientists. "Dave and I were surprised that the two distant basins, the Upper Colorado and the Salt/Verde, were so much in synch during periods of extremely high or extremely low flow." She added, "The recent joint drought, while severe, is not unprecedented when compared to those in the previous five centuries."

The findings of the first phase are being shared with representatives of various federal, state and local agencies such as the National Weather Service, U.S. Bureau of Reclamation, Arizona Department of Water Resources, Central Arizona Project and cities in the Phoenix metropolitan area.

The tree-ring study in partnership with The University of Arizona is the one of many initiatives taken by SRP in response to an ongoing drought that is in its 10th year. Even counting this past winter when 2,017,580 acre-feet of runoff – the first above-normal runoff season since 1998 -- filled the reservoirs on the Salt and Verde rivers, stream flows into the Salt and Verde have been below normal for eight of the last 10 January-through-May runoff seasons.

Phoenix-based SRP is the largest provider of water to the greater Phoenix metropolitan area.

The University of Arizona’s Laboratory of Tree-Ring Research was established in 1937 by A. E. Douglass, the founder of modern tree-ring science.

Mari N. Jensen | EurekAlert!
Further information:
http://www.arizona.edu

More articles from Studies and Analyses:

nachricht Multi-year study finds 'hotspots' of ammonia over world's major agricultural areas
17.03.2017 | University of Maryland

nachricht Diabetes Drug May Improve Bone Fat-induced Defects of Fracture Healing
17.03.2017 | Deutsches Institut für Ernährungsforschung Potsdam-Rehbrücke

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Northern oceans pumped CO2 into the atmosphere

27.03.2017 | Earth Sciences

Fingerprint' technique spots frog populations at risk from pollution

27.03.2017 | Life Sciences

Big data approach to predict protein structure

27.03.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>