Repairing a Century Old Valve
Water Supply watershed maintainers, machinists and other skilled workers have nearly completed the repair of a century-old valve at Ashokan Reservoir. The complicated repair took nearly four months, and it involved hauling approximately 18 TONS of metal to the surface from as deep as 90 feet within the reservoir’s upper gate chamber. The repair focused on a 60-inch gate valve that draws drinking water from the East Basin of Ashokan Reservoir. The valve is essentially a large gate that moves up and down to open a waterway to the East Basin. The gate is connected to a large nut that moves up and down when its threaded stem rotates, moving the gate along with it. Workers found that the valve failed because the threads on the nut had stripped, which prevented it from engaging with the threads on the stem. The nut and other components of the valve were all installed around the time the Ashokan Reservoir first delivered water to the City in 1915.
Removing the valve components was not easy and incorporated the use of two cranes — one to manipulate a man basket that held the workers, and a second to lift the heavy pieces to the surface. The effort to replace the valve began in November and is nearly finished. The crew is now re-installing parts of the actuator, including a newly fabricated actuator frame. They will soon test the valve before putting it back into service.
