In an example of the challenges water-strapped Western cities will face in a warming world, new research shows that every degree Fahrenheit of warming in the Salt Lake City region could mean a 1.8 to 6.5 percent drop in the annual flow of streams that provide water to the city.
By midcentury, warming Western temperatures may mean that some of the creeks and streams that help slake Salt Lake City’s thirst will dry up several weeks earlier in the summer and fall, according to the new paper, published today in the journal Earth Interactions. The findings may help regional planners make choices about long-term investments, including water storage and even land-protection policies.
Earth Interactions is jointly published by the American Geophysical Union, the American Meteorological Society, and the Association of American Geographers.
“Many Western water suppliers are aware that climate change will have impacts, but they don’t have detailed information that can help them plan for the future,” said lead author Tim Bardsley, with NOAA’s Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado Boulder. “Because our research team included hydrologists, climate scientists and water utility experts, we could dig into the issues that mattered most to the operators responsible for making sure clean water flows through taps and sprinklers without interruption.”
Bardsley works for the CIRES Western Water Assessment, from the NOAA Colorado Basin River Forecast Center in Salt Lake City. For the new paper, he worked closely with colleagues from the city’s water utility, the National Center for Atmospheric Research (NCAR), NOAA’s Earth System Research Laboratory and the University of Utah.
The team relied on climate model projections of temperature and precipitation in the area, historical data analysis, and a detailed understanding of the region from which the city utility obtains water. The study also used NOAA streamflow forecasting models that provide information for Salt Lake City’s current water operations and management.
The picture that emerged was similar, in some ways, to previous research on the water in the Interior West: Warmer temperatures alone will cause more of the region’s precipitation to fall as rain than snow, leading to earlier runoff and less water in creeks and streams in the late summer and fall.
“Many snow-dependent regions follow a consistent pattern in responding to warming, but it’s important to drill down further to understand the sensitivity of watersheds that matter for individual water supply systems,” said NCAR’s Andy Wood, a co-author.
The specifics in the new analysis—which creeks are likely to be impacted most and soonest, how water sources on the nearby western flank of the Wasatch Mountains and the more distant eastern flank will fare—are critical to water managers with Salt Lake City.
“We are using the findings of this sensitivity analysis to better understand the range of impacts we might experience under climate change scenarios,” said co-author Laura Briefer, water resources manager at the Salt Lake City Department of Public Utilities. “This is the kind of tool we need to help us adapt to a changing climate, anticipate future changes and make sound water-resource decisions.”
“Water emanating from our local Wasatch Mountains is the lifeblood of the Salt Lake Valley, and is vulnerable to the projected changes in climate,” said Salt Lake City mayor Ralph Becker. “This study, along with other climate adaptation work Salt Lake City is doing, helps us plan to be a more resilient community in a time of climate change.”
CIRES is a joint institute of NOAA and CU-Boulder.
Among the details in the new assessment:
Temperatures are already rising in northern Utah, about 2 degrees Fahrenheit (1.1 degrees Celsius) in the last century, and continue to climb. Summer temperatures have increased especially steeply and are expected to continue to do so. Increasing temperatures during the summer irrigation season may increase water demand.
Every increase in a degree Fahrenheit (0.56 degrees Celsius) means an average decrease of 3.8 percent in annual water flow from watersheds used by Salt Lake City. This means less water available from Salt Lake City’s watersheds in the future.
Lower-elevation streams are more sensitive to increasing temperatures, especially from May through September, and city water experts may need to rely on less-sensitive, higher-elevation sources in late summer, or more water storage.
Models tell an uncertain story about total future precipitation in the region, primarily because Utah is on the boundary of the Southwest (projected to dry) and the U.S. northern tier states (projected to get wetter).
Overall, models suggest increased winter flows, when water demand is lower, and decreased summer flows when water demand peaks.
Annual precipitation would need to increase by about 10 percent to counteract the stream-drying effect of a 5-degree increase in temperature.
A 5-degree Fahrenheit temperature increase (2.8 degrees Celsius) would also mean that peak water flow in the western Wasatch creeks would occur two to four weeks earlier in the summer than it does today. This earlier stream runoff will make it more difficult to meet water demand as the summer irrigation season progresses.
If you are a journalist with a press subscription to AGU journals, your subscription will not provide access to this paper.
Journalists and public information officers (PIOs) of educational and scientific institutions can view the paper’s abstract at http://journals.ametsoc.org/doi/abs/10.1175/2012EI000501.1 However, for access to the full paper, you must request a PDF copy of this article by sending an email to Thomas Sumner 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.
“Planning for an Uncertain Future: Climate Change Sensitivity”
Peter Weiss | American Geophysical Union
Innovative genetic tests for children with developmental disorders and epilepsy
11.07.2018 | Christian-Albrechts-Universität zu Kiel
Oxygen loss in the coastal Baltic Sea is “unprecedentedly severe”
05.07.2018 | European Geosciences Union
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
20.07.2018 | Information Technology
20.07.2018 | Materials Sciences