FOR IMMEDIATE RELEASE03-31
Submersible Vehicle Completes Inspection Voyage Of City’s Delaware
Aqueduct - “ULIISYS” Is Home
Trip Through 45 Miles Of Tunnel Maps Aqueduct For Future Repair Plans
begins its journey.
Commissioner Christopher O. Ward of the New York City Department of Environmental
Protection (DEP) announced today that an unmanned underwater vehicle has
completed a trip through the 45-mile Rondout-West Branch Tunnel of the Delaware
Aqueduct, one of the City’s main connections to its upstate water
supply. The inspection is Phase II of a project to map leaks in the Aqueduct
in order to develop a long-term repair plan.
“The data collected by the submersible vehicle will be analyzed
closely by DEP engineers to determine the precise nature and location
of the leaks we know to exist in the Delaware Aqueduct,” said Commissioner
Ward. “I would like to thank the Woods Hole Oceanographic Institution
and everyone who worked on this unique project for making it a success.”
is hoisted into position.
The self-propelled Autonomous Underwater Vehicle (AUV) -- dubbed ULIISYS
for Underwater Linear Infrastructure Investigation System -- was inserted
into the Aqueduct at 5:00 P.M. on Thursday, June 4, near the Rondout Reservoir
in Ulster County and was removed 16 hours later near the West Branch Reservoir
in Putnam County. Along the way, the vehicle took over 160,000 digital
images of the Aqueduct and recorded conditions using pressure sensors,
velocity sensors and hydrophones.
|The vehicle is positioned over the shaft.
The Delaware Aqueduct was constructed between 1939 and 1945, and typically
conveys around half of the City’s daily water supply from the Delaware
Water System in the Catskill Mountains. The Aqueduct is a 13.5 ft. diameter, concrete-lined tunnel that varies from 600 to 2,400 feet below ground.
The DEP is aware of at least two leaks in the Aqueduct at two fault
zones near Wawarsing and Roseton. The leaks combine to release between 10
million gallons of water a day and 36 million gallons a day, depending on
the amount of water the Aqueduct is carrying. Monitoring has shown that
the leaks have not grown in size in the last five years, and independent
engineering analyses have confirmed that the Aqueduct is not in danger of
collapse. If not fixed, though, over many years the leaks could develop
into threats to the Aqueduct.
|ULIISYS is launched at a shaft site in the Rondout Reservoir.
Other inspection methods used by the DEP include aerial flyovers of
the Aqueduct with infrared cameras, test borings to sample soil conditions,
acoustic testing and inspections of four tunnel shafts near the leaks.
The AUV is self-steering and has no tether attached to it. It is based
on the REMUS vehicle, which the Woods Hole Oceanographic Institution has
developed and extensively tested for the US Navy. A similar test vehicle
traveled the same route in January 2002 in preparation for this week’s
Digital photos are available. Please call for more information.