Water was more important than gold or silver or copper in the
development of the American West. West of the 100th meridian,
a year usually produces less than twenty inches of rainfall. Water
was the lifeblood of the arid Plains. The availability of cheap
water is an environmental factor that has made possible for such
western cities as Los Angeles, Phoenix, and Salt Lake City to
At first, many farmers believed that "water follows the
plow." They deluded themselves that if they planted trees
and built farms, rainfall would surely follow. It did not.
Windmills allowed late 19th century farmers to tap into
underground aquifers. In the 20th century, canals, aqueducts,
and the damming of rivers transformed a vast, arid region into
a region of sprawling cities and the nation's richest farmland.
Today, there are 1,200 major dams in California alone.
During the Great Depression, the construction of dams provided
employment to the jobless and a cheap source of electric power.
In the 1930s, five major water projects were constructed simultaneously,
including the California Central Valley project that drained Tulare
Lake, the largest freshwater lake west of the Mississippi. When
the Hoover Dam was built during the Depression on the Colorado
River, it was the largest dam on earth, standing 726 feet high.
It was surpassed by the Grand Coulee Dam, which stretched 4,290
feet across the Columbia River and created a 150-mile-long lake
as its reservoir. It opened in 1942 and for some time was the
world's single most powerful source of electricity. It was not
until the 1970s, that environmentalists begun to convince policy
makers of the negative ecological consequences of extensive dam
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