Posts tagged increase
Climate change could dry up Salt Lake City watersheds
Nov 1st
challenge Salt Lake City’s water supply
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.
“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.”
Among the details in the new assessment:
- Temperatures are already rising in northern Utah, about 2 degrees Fahrenheit 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 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 temperature increase 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.
Authors of the new paper, “Planning for an Uncertain Future: Climate Change Sensitivity Assessment Toward Adaptation Planning for Public Water Supply,” are Tim Bardsley, CIRES Western Water Assessment; Andrew Wood, NCAR and formerly of NOAA’s Colorado Basin River Forecast Center; Mike Hobbins, NOAA’s Earth System Research Laboratory, and formerly NOAA’s Colorado Basin River Forecast Center; Tracie Kirkham, Laura Briefer, and Jeff Niermeyer, Salt Lake City Department of Public Utilities, Salt Lake City, Utah; and Steven Burian, University of Utah, Salt Lake City.
Earth Interactions is jointly published by the American Geophysical Union, the American Meteorological Society and the Association of American Geographers.
CIRES is a joint institute of NOAA and CU-Boulder.
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Boulder Transit Center improvements to open Saturday
Oct 4th
On Saturday, Oct. 5, the Boulder Transit Center is scheduled to reopen to bus, bike and pedestrian traffic, thanks to funding from the 2011 voter-approved Boulder Capital Improvement Bond, a Colorado Department of Transportation (CDOT) FASTER grant, and the Regional Transportation District (RTD). The area around the Boulder Transit Center area has been under construction since late May 2013, with buses and passengers temporarily relocated to 14th Street between Arapahoe Avenue and Canyon Boulevard.
The Boulder Transit Center Area Improvements will provide better access and accommodations for buses, bicycles, and pedestrians, including:
- saw tooth bus bays for improved transit operations and passenger access;
- crosswalk bulb-outs to shorten pedestrian crossing distances;
- new urban design elements throughout the area; and
- through-traffic restrictions to minimize conflicts.
BTC before improvements
To enhance the efficiency of bus operations and increase pedestrian safety, the one-block section of 14th Street between Walnut Street and Canyon Boulevard has been permanently closed to auto traffic.
“The Boulder Transit Center improvements are made possible through regional cooperation and in direct response to community input,” states RTD Board Director Chuck Sisk, District O. “This is a vital bus transit hub that will see more than 600 scheduled bus departures daily.”
“With these improvements, the Boulder Transit Center is better prepared to accommodate the regional service increases anticipated with the addition of FasTracks Bus Rapid Transit on US 36,” said Director of Public Works for Transportation Tracy Winfree. “We appreciate passengers’ patience during the construction of these enhancements.”
For more information about the Boulder Transit Center Area Improvements, visit bouldercolorado.gov/bond-projects and select “Downtown Improvements” or call 303-441-3266.
For bus routes and schedules, visit www.rtd-denver.com or call RTD’s Telephone Information Center at 303-299-6000 or 303-299-6089 for the speech and hearing impaired.
–CITY–
More rain to come this evening
Sep 14th
Flash Flood Watch in Northeastern Colorado
Active for next 1 day, 8 hours Locations: Boulder And Jefferson Counties Below … Show more
Posted 5 hours, 47 minutes ago – National Weather Service
- How likely:
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The original text for this alert has been automatically reformatted to correct capitalization.
Potential for flash flooding in the mountains, and in and near the foothills this afternoon through Sunday afternoon.
A weak upper level trough will move slowly across the area this afternoon through Sunday. Meanwhile a cool front will move across Northeast Colorado late tonight and increase upslope flow.
Scattered showers and thunderstorms will develop this afternoon and linger into the early evening hours. Rainfall amounts will range from one quarter inch to one half inch. However stronger thunderstorms could produce up to an inch or more of rain in less than 45 minutes in a few locations.
There will be a lull in activity this evening however rain and a few thunderstorms may increase in the northern foothills and mountain areas north of I-70 after midnight as upslope flow develops. Additional rainfall amounts of one half inch to one inch may occur between midnight and 6 am Sunday morning in some locations. For Sunday there will be periods of rain along with a few thunderstorms in the mountains and in and near the foothills. Additional rainfall amounts of 1 to 2 inches could occur in some locations by late Sunday afternoon.
Thus if this additional heavy rainfall occurs then there could be more flash flooding as the ground is extremely saturated.
Flash Flood Watch in effect from noon MDT today through Sunday afternoon.
The National Weather Service in Denver has issued a Flash Flood Watch for portions of central Colorado, North Central Colorado and northeast Colorado, including the following areas, in central Colorado, Jefferson and West Douglas Counties above 6000 feet/gilpin/clear Creek/northeast Park counties below 9000 feet and south and southeast grand/west Central and Southwest Boulder/gilpin/clear Creek/summit/north and West Park counties above 9000 feet. In North Central Colorado, Larimer County below 6000 feet/northwest Weld County, Larimer and Boulder counties between 6000 and 9000 feet and South and East Jackson/larimer/north and northeast Grand/northwest Boulder counties above 9000 feet. In Northeast Colorado, Boulder and Jefferson counties below 6000 feet/west Broomfield County.
- From noon MDT today through Sunday afternoon.
- Additional rainfall amounts of 1 to 2 inches with up to 3 inches will be possible in the mountains, and in and near the foothills through Sunday afternoon. At this time the best chance of heavier rainfall appears to be from late tonight through Sunday afternoon. However Scatttered thunderstorms this afternoon into the early evening hours could produce up to an inch of rain in less than 45 minutes in some locations which could lead to flash flooding as well.
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