2015-04-22 / News

NYC DEP investigates sheen on Schoharie Reservoir

The New York City Department of Environmental Protection (DEP) last week provided the following update on its investigation and response to the surface sheen at Schoharie Reservoir:
After the sheen was discovered along the shore on Monday, water supply operators quickly shut down the Shandaken Tunnel Intake Chamber and surrounded the intake with absorbent boom. An analysis of water samples taken from the sheen determined that the material was motor oil or hydraulic oil. Oil was not found in the water samples collected from inside the intake chamber.

Sheen had dissipated
The sheen, which had dissipated by Tuesday, is not currently visible, nor are any odors detectable at the site. Three layers of boom remain deployed at the intake, and two layers of boom remain in place as a precaution at the tunnel outlet alongside the Esopus Creek.
On Thursday evening, DEP reactivated the Shandaken Tunnel Intake Chamber after consulting with its regulators. Local elected officials and stakeholders have also been notified. Because any lingering oil would remain in suspension atop the water, and the intake structure is located at the bottom of the reservoir, DEP is confident that none of the material will be conveyed through the Shandaken Tunnel. In addition to absorbent boom already deployed at both ends of the tunnel, DEP is taking several other steps that have been reviewed by regulators.
DEP’s water quality staff will implement an enhanced monitoring plan at the Shandaken Tunnel intake and outlet. Samples will be taken Friday, Sunday, Tuesday, and then once a week to ensure oil is absent from the water being conveyed from Schoharie Reservoir.

Similar incident
This monitoring plan is consistent with the testing that was done after a similar sheen was discovered at Pepacton Reservoir in 2012. DEP will also conduct daily visual inspections at Schoharie Reservoir and the Shandaken Tunnel Outlet for any sign of the sheen. Coincident with these actions, DEP is working on a plan to remove the tank once the ice has melted and work conditions are safe.
Because the Shandaken Tunnel had been shut down for several days, its reactivation on Thursday evening created a brief spike in turbidity that soon returned to normal levels. DEP is currently conveying 300 million gallons per day through the tunnel.

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