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August 15, 2007

DiNapoli Urges NYC to Better Safeguard Its Drinking Water Supply

Leaking Tunnel Now at Higher Risk of Failure

The New York City Department of Environmental Protection (DEP) should expedite its plans to repair leaks in the Delaware Aqueduct System’s Rondout-West Branch Tunnel (RWB), which each day leaks up to 35 million gallons of clean drinking water, according to an audit report State Comptroller Thomas P. DiNapoli released today.

The tunnel carries water from the 63-year-old Delaware Aqueduct System, which supplies more than half of the 1.2 billion gallons of drinking water consumed each day in the City. DiNapoli said that although DEP has been aware of the leaks since 1988, it has only taken limited action to address the problem and has not developed an emergency response plan to deal with a potential collapse of the tunnel.

“Over the course of a year, losing 35 million gallons of water every day adds up to about 10 days’ worth of water for every man, woman and child in New York City,” DiNapoli said. “But this is more than just lost water; it’s a potential catastrophe.”

“The bridge collapse in Minneapolis and the steam pipe explosion in Manhattan are tragic reminders that we must repair and maintain our infrastructure. If the leaks in the tunnel lead to a complete collapse, New York would lose half its drinking water supply in an instant. DEP has to speed up plans to repair the tunnel, and it has to develop an emergency response plan in the event that the tunnel does collapse. Repairing the tunnel will be costly, but not as costly as shutting down half the City’s water supply.”

The DiNapoli audit report also found that:

  • While DEP has gathered a large body of technical information on water leaks in the RWB tunnel, it has made no repairs since first discovering the leaks 19 years ago;
  • DEP has spent more than $28 million on engineering consultant services since 1998, but has failed to consistently follow the consultant’s testing and monitoring recommendations;
  • Water loss due to leaks in the RWB has increased to between 30 million to 35 million gallons per day from the 15 million to 20 million gallons per day estimated in 1992;
  • A DEP investigation in 2003 revealed that the RWB was heavily cracked throughout a 7,000-foot linear stretch;
  • DEP’s primary consultant has elevated the risk of catastrophic tunnel failure occurring between 2005 and 2009 to a probability ranging from 0.1 percent to 1 percent, which is 10 times the greater than the preferred risk of .01 percent; and
  • DEP does not have in place comprehensive emergency response plans to address a catastrophic or other unexpected event that might disrupt the flow of water through the RWB tunnel.

Click here for a copy of the audit.



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