Geoscience Reference
In-Depth Information
h e i lm goes on to describe the region's rapidly declining water table,
the result of more groundwater being pumped out of the ground than could
be replenished by rain and runof . h e region was pumping an estimated
170 million gallons of groundwater per day. It was said, however, that the
Colorado River could provide one billion gallons of water per day—over
six times the amount they actually needed at the time. It is not surprising,
then, that during California's prolonged and deep Dust Bowl drought voters
approved a bond to fund the 242-mile Colorado River Aqueduct, which was
completed in 1941.
In Northern California, the city of San Francisco began looking eastward
to the Sierra Nevada for a more reliable source of water in the early twentieth
century. h e city set its sights on the Tuolumne River and proposed to dam
the Hetch Hetchy Valley in Yosemite National Park. A battle between the
Sierra Club (led by John Muir) and the city of San Francisco (with Gif ord
Pinchot, the i rst chief of the U.S. Forest Service) lasted between 1902 and
1913. In 1913, the city was authorized to build a dam on the Tuolumne River,
transforming the Hetch Hetchy Valley into a large reservoir for San Francisco
and other Bay Area cities—a project that would not be fully completed
until 1934.
Two decades later, the California Aqueduct was built to bring water
from the wetter northern half of California to the San Joaquin Valley and
Los Angeles. h is project was part of the larger “Central Valley Project”
funded by the Roosevelt administration during the Great Depression. h ese
twentieth-century water projects led to a population explosion in California,
from 500,000 in 1920 to over 37 million in 2012.
In the Southwest, much of its population growth would not have been
possible if not for water development, particularly of the Colorado River.
h e Colorado drains rain and meltwater from states in its upper drainage
basin—Wyoming, Colorado, Utah, and New Mexico—and brings this
water into the deserts of the lower basin, including Nevada, Arizona, and
California (see i gure 31). In the past, it was a capricious river: a sleepy stream
one day but (following a winter storm or a summer monsoon downpour) a
raging torrent the next.
h e taming of the Colorado River began with the construction of Hoover
Dam in the 1930s, followed by numerous other dam projects on the Colorado
in the following decades. h ese water projects have reduced devastating l ash
l oods but have also decimated the native i sh species that were adapted to
the natural conditions on the river. h
e Colorado now provides water and
