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

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 whe n 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 research was funded by SRP, the city of Phoenix and the U.S. Bureau of Reclamation.

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.


'"/>

Source:University of Arizona


Related biology news :

1. Anti-bacterial additive widespread in U.S. waterways
2. NCAR analysis shows widespread pollution from 2004 wildfires
3. Climate change drives widespread amphibian extinctions
4. Exotic crab poised for widespread UK invasion
5. Vitamin D deficiency widespread during pregnancy
6. Yellowstone microbes fueled by hydrogen, according to U. of Colorado study
7. Brain networks change according to cognitive task
8. Morning grogginess more debilitating than sleep deprivation, according to CU-Boulder study
9. Biodiversity key to sustainable biofuel according to University of Minn. researchers findings
10. Good times ahead for dinosaur hunters, according to U of Penn scientists dinosaur census
11. With cellulosic ethanol, there is no food vs. fuel debate according to MSU scientist
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:1/20/2016)...   MedNet Solutions , an innovative SaaS-based eClinical ... research, is pleased to announce the attainment of record-setting ... result of the company,s laser focus on (and growing ... it,s comprehensive, easy-to-use and highly affordable cloud-based technology platform. ... MedNet growth achievements in 2015 include: , ...
(Date:1/15/2016)... JUAN, Puerto Rico , Jan. 15, 2016 /PRNewswire/ ... companies big and small to find new ways to ... driven culture. iOS and Android ... device based on biometrics, transforming it into a hardware ... request that users swipe their fingerprint on their KodeKey ...
(Date:1/11/2016)... , Jan. 11, 2016 Synaptics Incorporated ... interface solutions, today announced that its ClearPad ® ... (TDDI) products won two separate categories in the 8 ... Innovator and Best Technology Breakthrough. The Synaptics ® ... a simplified supply chain, thinner devices, brighter displays and ...
Breaking Biology News(10 mins):
(Date:2/9/2016)... ... February 08, 2016 , ... ... services, announced today the launch of its revamped and improved website. In an ... service solutions, the redesigned website will better communicate how the company designs and ...
(Date:2/9/2016)... ... February 09, 2016 , ... The publishing industry has ... publishing is one of the popular publication models that has received wider acknowledgement ... and 3000+ International Conferences across the globe, OMICS International is all ...
(Date:2/9/2016)... LONDON , February 9, 2016 ... replace paper and protect IP   E-WorkBook ... will be rolled out in Germany ... and protect valuable IP. Users will be able to search ... or experiment as part of the application, to boost collaboration ...
(Date:2/8/2016)... , Feb. 8, 2016 /PRNewswire/ - BIOREM Inc. (TSXV: BRM) ... top ten finalists for clean technology companies in the TSX ... top 10 companies listed on the TSX Venture Exchange, in ... gas, clean technology & life sciences, diversified industries ... weighting given to return on investment, market cap growth, trading ...
Breaking Biology Technology: