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DEP Reactivates Shandaken Tunnel to Supplement Natural Flow in Esopus Creek

DEP Reactivates Shandaken Tunnel to Supplement Natural Flow in Esopus Creek

New York — The New York City Department of Environmental Protection (DEP) temporarily halted some of its work at the Shandaken Tunnel Intake Chamber because of dry weather, which required the city to reactivate the 18-mile-long tunnel that supplements the natural flow of water in the Esopus Creek. DEP shut down the tunnel — which conveys water from Schoharie Reservoir to the Esopus Creek and Ashokan Reservoir — on March 4 to facilitate replacement of flow control gates at the intake chamber. That shutdown was scheduled to last until April 30.

The timing and duration of the shutdown was planned in close coordination with the state Department of Environmental Conservation (DEC). Because the tunnel contributes 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. During each shutdown, DEP and DEC hold weekly meetings to review the current and forecasted flow of water within the creek to decide whether the shutdown can continue for its full duration.

DEP reactivated the tunnel March 25 after that weekly discussion with DEC. A period of dry weather, combined with relatively little snowpack in the watershed, caused the natural flow in the upper Esopus Creek to drop below a desired threshold. Reactivation of the Shandaken Tunnel will provide an additional 200-250 million gallons of water per day to the creek at the portal outlet in Allaben.

The shutdown was meant to allow divers to install a massive plug within the intake structure at Schoharie Reservoir, setting the condition for them to safely remove and replace eight gates that control the flow of water into the tunnel. During the first three weeks of the shutdown, divers installed the plug but did not complete the construction of the bypass pipe through the plug to allow work to begin on the gates. The work is part of a $47 million rehabilitation of the Shandaken Tunnel Intake Chamber.

Engineers and scientists from both agencies will continue to review the hydrologic forecast to determine whether the shutdown can resume later this spring. DEP will keep its neighbors in the watershed apprised of plans for the project as they evolve.