Hurricane Sandy

stirred up enough sediment to cloud New York City's water supply.

According to The New York World, the city's water supply experienced levels of high turbidity (extra sediment, no extra charge!) in late October as the storm rocked the aging infrastructure of the Catskill-Delaware watershed, violating the Clean Water Act for 105 minutes.The city is allowed five of these violations in a ten-year period before a filtration plant costing as much as $10 billion has to be built. So far, there have been three such events since 2005.[See update below]

“Turbidity is an issue that the city needs to worry about,” Eric Goldstein, head of the National Resources Defense Council told the World. “The system is sensitive, and maybe even extra-sensitive to turbidity from storms. It’s a definite warning sign.” A Yale University study linked powerful storms caused by global warmed to increased turbidity levels in watersheds.

High turbidity can weaken the effectiveness of the disinfecting chemicals in the water supply, causing intestinal problems in those with weaker immune systems. A Harvard study showed that high turbidity in the water supply correlates to a higher emergency room admission level.

The cost of the filtration plant could cost each household $157 a year by 2018, but what's $157 when you're completely under water?

[UPDATE] Eric Goldstein, the director of the NRDC's New York division, writes to point out that New York City is not on the verge of violating the Safe Water Drinking Act.

It is true, as your headline states, that “Global Warming Is Affecting NYC’s Drinking Water.” And your story correctly quotes me as identifying turbidity as a serious threat to New York City’s priceless and irreplaceable water supply. But the article’s conclusion that a recent turbidity exceedance following Hurricane Sandy means that the city is on the verge of violating the Safe Drinking Water Act’s filtration avoidance provisions is inaccurate. Turbidity is indeed a long-term threat to water quality in New York City’s Catskill and Delaware systems and to many other supplies as well. And the impacts of the climate crisis are likely to make the turbidity problem more challenging in years to come. But to say all that does not mean that New York City faces a short-term threat of having to spend billions and billions of dollars to install massive filtration equipment for its Catskill and Delaware system. The article unfortunately misinterprets the complex and technical details of the Safe Drinking Water Act and its implementing regulations. The best long-range strategy for safeguarding our upstate water supply remains cost-effective pollution prevention—taking steps to protect vulnerable land parcels from development, preventing industrial activities on watershed lands and preserving the rural character of the region. Of course, addressing the root cause of our climate crisis—the burning of fossil fuels—makes sense not only to protect our water supply from turbidity problems but for many other sound ecological and economic reasons.

Another official who works closely to monitor the city's water supply adds that the New York World's story is "inaccurate" because the three events cited do not actually qualify as "events" under the Safe Drinking Water Act. "We have some of the best drinking water in the world—we're one of five sites in the country that the EPA has granted a waiver of filtration requirement," the official said.