The Treatment - The Ripple Effect: The Fate of Freshwater in the Twenty-First Century - page 43

(a parasitic microorganism), respectively. That same year 69 people died and an estim-
ated 403,000 were sickened by a Cryptosporidiumoutbreak in Milwaukee tap water, in
the largest recorded outbreak of waterborne disease in US history. A year later, Las Ve-
gas suffered the nation's second-largest outbreak of Cryptosporidium,which killed 43
people and sickened 132 more. Between 2001 and 2006, another eighty-five minor out-
breaks of waterborne illness may have been partly the result of sewage contamination.
It rains or snows in New York City every three and a half days on average, providing
forty-four inches of precipitation a year. Before the city's surfaces were sealed by con-
crete and tarmac (which began two centuries ago), rain filtered into the soil and wet-
lands and was sucked up by vegetation. But as New York City expanded, impermeable
streets and buildings increasingly covered absorbent earth. Between 1970 and 2000,
more than nine thousand acres of land were paved over. Even the soil in some city parks
and athletic fields has become so tightly compacted by heavy use that it is nearly imper-
meable. And in the twentieth century, 90 percent of New York's spongy wetlands were
destroyed to make room for development. As a result, most of the city's precipitation
washes directly into the sewers.
On an average sunny day, New York City residents discharge about 1.4 billion gallons
of sewage , made up of household waste, street runoff, and industrial effluent, into more
than seven thousand miles of sewer pipe. The system was carefully designed so that
most of this wastewater flows by gravity alone. After being processed at one of fourteen
pollution control plants, the treated effluent is flushed back into local rivers and the har-
bor. In a downpour, New York's sewage system can absorb the crucial first five minutes
of sustained rain—the “five-minute flush”—when storm water surges through the pipes
and rushes into treatment plants. But if the rainfall is sustained or arrives in an intense
burst, trouble can quickly build up in the system.
A drought in 2002 kept CSOs to a minimum and local waters were relatively clean.
But the rainy summers of 2003 and 2004 caused so many CSOs that New York waters
were declared unhealthy, and beaches were repeatedly closed. The swimming leg of a
triathlon was canceled due to the pollution from CSOs.
Most notorious was the sultry afternoon of August 14, 2003 , when a massive power
outage—caused by surging electricity demand, computer malfunctions, and power lines
snagged in trees in Ohio—led to a rolling blackout that knocked out electricity to
roughly 45 million people in the Northeastern and Midwestern United States, and an-
other 10 million in Canada. In New York, most of the city's wastewater treatment plants
used backup generators to keep functioning. But at two plants, the generators did not
work, and 30 million gallons of untreated human waste was illegally discharged into the
city's waters. This led to a massive increase of fecal coliform in New York Harbor and