The Dammed - The Ripple Effect: The Fate of Freshwater in the Twenty-First Century - page 155

seepage. Silt that normally flows downstream is trapped behind dams, which chokes the
flow of nutrients and water, clogs hydroelectric turbines, and dooms reservoirs to short
life spans.
Dams require constant maintenance, and without it they become hazardous.
Between 2005 and 2009, there were 132 dam failures across the United States , and a
further 434 serious “incidents,” which could have led to disaster without intervention,
according to the Association of State Dam Safety Officials (ASDSO). From 1998 to
2008, the number of dams considered “deficient”—meaning they are susceptible to col-
lapse—rose 137 percent, from 1,818 to 4,308.
Dam opponents point to a few dramatic failures as proof that dams are not to be
trusted. The most infamous was the Johnstown Flood, caused by the rupture of the
South Fork Dam in western Pennsylvania by heavy rains in 1889: when the dam burst,
it sent 4.8 billion gallons of Conemaugh River water rushing downstream, which killed
over 2,200 people and caused $17 million worth of damage. (The flood was named after
a town wiped out by the flood.) Another notorious flood was caused by the collapse
of the St. Francis Dam , northwest of Los Angeles: it gave way at three minutes before
midnight on March 12, 1928, sending twelve billion gallons crashing towards the Pacif-
ic, and killing about 600 people. The St. Francis was designed by William Mulholland,
the legendary head of the Los Angeles Department of Water and Power; he accepted re-
sponsibility for the tragedy, which destroyed his career.
The chance of a twenty-first century Johnstown Flood or St. Francis disaster are
minute, government officials say, and state and federal agencies have put emergency
plans and safety regulations in place. But “the lack of funding for dam upgrade has be-
come a serious national problem,” ASDSO charges. “The number of dams identified as
unsafe is increasing at a faster rate than those being repaired.” To repair the most critical
dams will cost $16 billion, and take a dozen years, the association estimates; the price
to recondition all US dams could be $50 billion. At this writing, Congress was debating
a massive economic stimulus package that contained a $40 billion investment in infra-
structure, including dams, roads, bridges ports, rail and water systems.
An early debate over dams stands as a defining moment for the environmental move-
ment. In 1912, San Francisco proposed building the Hetch Hetchy Reservoir , inside the
remote northwestern corner of Yosemite National Park, to meet the city's growing de-
mand for power and water, including for fire protection (in 1906, the devastating San
Francisco earthquake and an ensuing conflagration killed some three thousand people).
But damming a valley on national parkland required federal approval, and the decision
to grant it was sharply disputed. The fight galvanized dam opponents and split the nas-
cent environmental movement into two factions: protectionists, led by John Muir , who
held that nature is sacrosanct and that humans are intruders; and the more established