Water Tunnel Project Moves Forward in New York

The New York City Department of Environmental Protection (DEP) today announced an eight-week shutdown of the tunnel that carries water from Schoharie Reservoir to the Esopus Creek and Ashokan Reservoir. The shutdown, which is scheduled to last from March 1 – April 30, will allow divers to safely enter the intake chamber at Schoharie Reservoir and take detailed measurements to support a $47 million upgrade of its waterworks.

The timing and duration of the shutdown was planned in close coordination with experts from New York’s Department of Environmental Conservation. Because the tunnel contributes additional water to the Esopus Creek, the shutdown was planned to coincide with the period of spring rains and melting snow that have historically provided the greatest quantity of natural flow within the creek. The temperature of water in the creek will also not be a concern during early spring.

The work this spring will support design and construction for the full-scale rehabilitation of the Shandaken Tunnel Intake Chamber. That facility controls the flow of drinking water from Schoharie Reservoir into the Shandaken Tunnel, which travels 18 miles through the Catskill Mountains. That tunnel discharges into the Esopus Creek to help refill Ashokan Reservoir throughout the year.

The rehabilitation project includes replacing eight sluice gates that control the flow of water into the tunnel by opening and closing large waterways. The gates within the intake structure were installed during the 1920s when Schoharie Reservoir was built. Three of the gates are currently stuck because they broke off their lifting mechanisms and became wedged in place. Before the gates can be removed and replaced, skilled divers must descend about 130 feet into the chamber’s shaft, using sonar equipment to take precise measurements of the gates and the grooves that guide them. These measurements will be used to fabricate new gates, lifting mechanisms and other infrastructure to restore the full function of the intake chamber.

Construction of the project will require future shutdowns and safety precautions. The tunnel will be shut down for two months in 2019 while workers install a plug and bypass system within the intake structure. The plug will block the flow of water into the Shandaken Tunnel and prevent divers from being pulled into the tunnel while they remove and replace the old gates. Once completed, the bypass system will allow DEP to safely move up to 100 million gallons of water each day through the plug without harming the divers or their work.

DEP will then replace the sluice gates once the plug is installed. That work will take approximately two years, from 2019 to 2021. DEP’s ability to move water from Schoharie Reservoir into the Esopus Creek will be limited during that time. While the gravity-fed bypass pipe can convey up to 100 million gallons of water each day, its capacity at any given time will depend upon reservoir elevation.

A portion of the limited-capacity bypass system will be left in place and modified after the rehabilitation of the Shandaken Tunnel Intake Chamber is finished. The pipe will be connected to an articulating arm, which can pivot up and down, giving DEP the ability to draw water from multiple depths within Schoharie Reservoir for the first time. The current intake structure only draws water from the bottom of the reservoir. In the future, this intake will help DEP convey higher quality water from Schoharie Reservoir and extend the life of its cold-water bank that supports the trout fishery on the Esopus Creek. Workers plan to partially core a 5-foot-diameter cylinder through the outer wall of the intake chamber this spring in preparation for the bypass pipe.

The project is expected to be completed by the end of 2021.

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