[env-trinity] KQED Bay Area Public TV 11 10 2010
bwl3 at comcast.net
Fri Nov 12 08:49:05 PST 2010
Running Dry? California Water Supply at Risk
By Gretchen Weber
Lake Mead is the largest reservoir in the country. It's located on the
Colorado River, which provides water for about 27 million people in seven
states, including millions of Californians. In fact, California gets more
than a trillion gallons of water from the Colorado River each year, directly
from Lake Mead via the Colorado River Aqueduct which snakes across the
Eighteen million people in Southern California are dependent on the Colorado
for 40% of their water. And for some agricultural operations, that
percentage is more like 100. Needless to say, it's a critical source of
The thing is, after 11 years of dry conditions in the region, Lake Mead
dropped to its lowest level ever in October. And so far, it's stayed there.
Since Hoover Dam was completed in the 1937 the water level has never been so
low. As of today, it's at 38% of capacity. And it's not just Lake Mead
The whole Colorado River storage system is at just 55% of capacity, so
forget just filling it up with water from upstream. Of course, winter's on
its way, and with that, precipitation, so the lake shouldn't stay quite so
low for long. And, thanks to a wet year, Northern California's reservoirs
are doing well.
But when you think about this water shortage in terms of population trends
and the changing climate, the future for water in the Southwest looks grim.
Population areas supplied by the Colorado River are some of the fastest
growing in the country. So demand is going up.
At the same time, scientists and water managers say the supply will go down.
The region is expected to get warmer and drier in the coming decades, which
means less precipitation, and more specifically, less snow. Which means
that of the precipitation that does come, more will come as rain, which is
harder to capture and store for use throughout the dry summer months.
In fact, studies show that the river's flow is likely to decrease 10-15% in
coming decades due to climate change, according to the Bureau of Land
Management's Terry Fulp, and, he said, the demand is already outpacing the
"The supply and demand curves have crossed," he told me last May.
The question of just how long the Colorado River can continue meet the needs
of seven states with growing populations, depends on how quickly those
supply and demand curves are diverging. Scientists have given varying
estimates of when Lake Mead will go dry, but recent studies estimate a 50-50
chance that it could happen before 2057. (Earlier studies had estimated it
as soon as 2021.) The state's population is expected to increase by half,
to nearly 60 million, by 2050.
So, Californians, what happens then? And what should we be doing now to
prepare? It might be worth thinking about. In 2060, taking shorter showers
and turning off the water when you brush your teeth might not be enough.
Byron Leydecker, JcT
Chair, Friends of Trinity River
PO Box 2327
Mill Valley, CA 94942-2327
415 383 4810 land
415 519 4810 mobile
<mailto:bwl3 at comcast.net> bwl3 at comcast.net
<mailto:bleydecker at stanfordalumni.org> bleydecker at stanfordalumni.org
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