DEP Retrieves Micro-tunnel Boring Machine from Waters of Schoharie Reservoir

July 12, 2019

Retrieval of tunneling machine marks another milestone for $400 million infrastructure program at Schoharie Reservoir

The New York City Department of Environmental Protection (DEP) this week retrieved a micro-tunnel boring machine from the waters of Schoharie Reservoir, marking another milestone for the $400 million program to upgrade infrastructure and improve operational flexibility at the northernmost reservoir in the City’s water supply system. The micro-tunnel boring machine (MTBM) was carefully lifted on Wednesday from approximately 135 feet below the surface of the water. In January the machine finished excavating 2,118 linear feet of tunnels that will be used to release water downstream of the reservoir into Schoharie Creek.

“The completed excavation and retrieval of this tunneling machine are major milestones in our work at Schoharie Reservoir,” DEP Commissioner Vincent Sapienza said. “The new release works and upgrades to our intake structure at the reservoir will provide DEP with more operational flexibility to send the best-quality drinking water to New York City and support the ecological health of Schoharie Creek.”

The 9.5-foot-diameter tunneling machine began its work in 2017. The tunnel was excavated in two segments, both starting at a 185-foot-deep shaft located alongside State Route 990V. The first leg of the tunnel stretched 1,188 feet from the shaft to the eastern bank of Schoharie Creek. The second leg measured 930 feet from the shaft to the bottom of Schoharie Reservoir, where the MTBM excavated through the reservoir bottom on January 19. After the winter ice melted, engineers set up a system of barges and lifts to remove the MTBM from the water on Wednesday. The entire tunneling effort was unique – it was one of the largest excavations ever by an MTBM that included a deep-water retrieval of the machine.

MTBMs are unmanned machines that are operated by remote control from the surface. Operators tracked the progress and performance of the machine by watching it on monitors inside a control room. Workers only entered the machine if it needed maintenance, or if cutters on the head of the machine needed to be replaced.

Significant work remains on the $142 million project to build a release works at Schoharie Reservoir. Now that the release tunnel is excavated, workers will focus on lining the tunnel and installing its intake structure. Work is also continuing on the eastern shore of the Schoharie Creek, where crews are building a valve chamber that will control the flow of water from the reservoir into the creek. The new release works will give DEP the ability to release water downstream of the reservoir into Schoharie Creek to facilitate dam maintenance, respond to potential emergencies, mitigate flood risk for downstream communities, and enhance downstream habitat for fish and wildlife.

The release works are part of a $400 million program to upgrade all the water supply infrastructure at Schoharie Reservoir. The program began with the full-scale rehabilitation of Gilboa Dam, which was completed in 2014. It also includes significant repairs and upgrades at the Shandaken Tunnel Intake Chamber, which conveys drinking water from the reservoir into an 18-mile tunnel on its way to Ashokan Reservoir in Ulster County. Learn more about the Schoharie Reservoir infrastructure program.

About Schoharie Reservoir

Schoharie Reservoir, the northernmost reservoir in New York City’s water supply system, was built from 1919 to 1927. It was formed by the construction of Gilboa Dam, 2024 feet long and 182 feet high, which impounded the waters of Schoharie Creek. Schoharie Reservoir can store up to 19.6 billion gallons of water, and it accounts for nearly 15 percent of the drinking water delivered to New York City each day. Schoharie Reservoir collects water from a 314-square-mile watershed. It diverts that water through the 18-mile Shandaken Tunnel, which discharges into the Esopus Creek where it travels another 11 miles before entering Ashokan Reservoir. From Ashokan Reservoir, the water flows south through the 92-mile-long Catskill Aqueduct to New York City.

DEP manages New York City’s water supply, providing more than 1 billion gallons of high-quality water each day to more than 9.6 million New Yorkers. This includes more than 70 upstate communities and institutions in Ulster, Orange, Putnam and Westchester counties who consume an average of 110 million total gallons of drinking water daily from New York City’s water supply system. This water comes from the Catskill, Delaware, and Croton watersheds that extend more than 125 miles from the City, and the system comprises 19 reservoirs, three controlled lakes, and numerous tunnels and aqueducts. DEP has nearly 6,000 employees, including almost 1,000 scientists, engineers, surveyors, watershed maintainers and other professionals in the watershed. In addition to its $70 million payroll and $168.9 million in annual taxes paid in upstate counties, DEP has invested more than $1.7 billion in watershed protection programs—including partnership organizations such as the Catskill Watershed Corporation and the Watershed Agricultural Council—that support sustainable farming practices, environmentally sensitive economic development, and local economic opportunity. In addition, DEP has a robust capital program with $20.1 billion in investments planned over the next decade that will create up to 3,000 construction-related jobs per year. For more information, visit, like us on Facebook, or follow us on Twitter.