'This is frightening'
- 'This is frightening'
By PHIL WHITE
Star-Tribune correspondent Friday, October 06, 2006
LARAMIE -- Recent drought and climatic warming, whether natural or
human-caused, are having significant effects on Wyoming�s water
supplies, the deputy state engineer said at a water conference at the
University of Wyoming Thursday.
Harry LaBonde said the drought has forced his office to restrict water
use on some streams that have not been regulated in many years, if
ever, and to enforce restrictions sooner in the season.
He said that only unusual precipitation in the Colorado River�s lower
basin avoided a "call" upon the upper basin states in 2005 pursuant to
the Colorado River Compact, which allocated certain amounts of water
to each of the states along the Green and Colorado rivers. LaBonde
said that Lake Powell in southern Utah, which stores water to meet
demands of the downstream states, was at only 38 percent of capacity
in 2004, down from 94 percent in 1999.
Mike Besson, director of the Wyoming Water Development Commission,
said Wyoming should expect to see 30 percent less water in the not-too-
�This is frightening,� he said. �We will have to reduce our use.�
One way to do that, he said, is to substitute wind-generated electric
power for coal-fired generation, which requires large amounts of water
for cooling. Besson also mentioned a system used in Arizona where
water is spread over alluvial layers and soaks in, returning to the
He said groundwater will become a more important source of water as
the climate changes. �The next big hurdle will be quantifying the
groundwater," he said.
Several speakers said the higher temperatures being experienced in
recent years have caused an earlier runoff of mountain snowpack, which
means less water is available during crucial parts of the growing
season. Besson said the water has been coming off about 35 percent
sooner than historic levels.
He also said the state needs to move forward with reservoirs to retain
more water in the state, especially in the Green River Basin. He said
his office began evaluating 24 opportunities for dams in 2000 and has
identified two proposals as the most promising for increased storage
in the Ham�s Fork drainage of the Green River: raising the Viva
Naughton dam and placing a new dam in the Dempsey Basin.
State climatologist Steve Gray said Wyoming is the fifth-driest state
in the nation, averaging only 6 or 7 inches of precipitation per year
in the basins of the southwest quarter. Wyoming is in the seventh or
eighth year of a severe drought, he said, which has exposed the
vulnerabilities of the state�s water supply.
�The majority of the water comes from a single source, mountain
snowpack,� Gray said, �and the mountains comprise only about 7 percent
of the state�s land area.�
Gray said scientists agree that global warming is at least in part due
to human activities such as burning fossil fuels, deforestation and
�If we continue with business as usual,� he said, �scientists predict
that temperatures will rise up to 6 degrees Celsius.�
Very small changes in average annual temperatures can have large
effects on water use in Wyoming, he said.
Noting that some scientists predict increased precipitation in Wyoming
from the temperature increase, Gray warned that the increase in
evaporation from a rise of only 2 degrees in temperature would offset
a 15 to 20 percent increase in precipitation. That kind of warming, he
said, would cause more of the state�s precipitation to come in the
form of rain instead of snow, further reducing the storage effect of
Gray said tree ring studies of streamflow in the Colorado River show
huge fluctuations over the past 1,100 years. However, the levels of
precipitation enjoyed by that drainage in the 20th century, before the
onset of the drought, were far above the historic means, he said.