July 27, 2020

DEP to start subsurface analyses for future upgrades to dam and dikes at Ashokan Reservoir

Drilling and excavating will require temporary closures at the Ashokan Promenade and Ashokan Rail Trail to ensure safety of public and workers

The New York City Department of Environmental Protection (DEP) today announced that field work will begin next month to support future upgrades to the dam and dikes that impound water at Ashokan Reservoir. The work will focus on gathering soil and bedrock samples that are needed for the engineering and design of upgrades at each structure. The subsurface investigations are connected to the Ashokan Century Program, a comprehensive, multi-year capital program to upgrade the dam, dikes, chambers and other infrastructure at Ashokan Reservoir. The program—which comprises the largest public works project in the Catskills in more than 50 years—was announced in 2017.

“The bedrock and soil samples DEP will collect through the end of the year are essential as our team begins to design upgrades for each of the structures that form Ashokan Reservoir,” DEP Commissioner Vincent Sapienza said. “Drilling and excavating to collect that data will require temporary closures at some recreation areas to ensure the safety of the public and our workers. I want to thank our watershed neighbors in advance for their patience, and for helping DEP get this project started safely and successfully.”

The subsurface investigations will begin in early August. The work includes drilling at each of the structures to collect soil and bedrock information from deep below the surface. DEP will also use an excavator at some locations to dig temporary test pits where roadway or drainage upgrades are anticipated. Each of the excavated areas will be refilled on the same day, and seeded. Work at each location will only happen during normal business hours, Monday through Friday.

During the summer and fall, the field work will require temporary shutdowns of certain portions of the Ashokan Promenade and the Ashokan Rail Trail. The following is a description and estimated schedule for the work.

Work at the Ashokan Promenade

The Ashokan Promenade is a paved walkway atop the Olivebridge Dam, West Dike and Middle Dike on the south side of Ashokan Reservoir. The walkway is accessed through two parking lots off Route 28A.

DEP will conduct subsurface investigations at these structures in August, September, and early October. Field work will also be performed at East Dike during that time, where there is no public access. Work in the public access areas will be performed by a drill rig to gather soil and rock samples - known as geotechnical borings—from deep within each of the structures. Work areas around the drill rigs will be approximately 10 feet wide and 50 feet long. They will be surrounded by fencing and a visual barrier to protect the safety of workers and the public.

The westernmost portion of the Ashokan Promenade, which sits atop Olivebridge Dam, will be closed Monday through Friday for approximately seven weeks while DEP performs the work. The dam will be closed during the week from late August until early October. That portion of the promenade will re-open each Friday evening, Saturday and Sunday. DEP must close Olivebridge Dam because it is too narrow to safely route visitors around the worksite.

The easternmost stretch of the Ashokan Promenade will remain open while workers perform the geotechnical borings. On that portion of the walkway, which is wider, DEP will set up a safe work zone and direct visitors around it. Work on that part of the walkway will begin during the first week of August.

Work near the Ashokan Rail Trail

The Ashokan Rail Trail is an 11.5-mile-long trail that occupies a former railroad corridor on the north side of Ashokan Resevoir. That side of the reservoir includes three impoundments—West Hurley Dike, Woodstock Dike and Glenford Dike. A parking lot for the Ashokan Rail Trail is located alongside Woodstock Dike, and the trail itself runs atop Glenford Dike for approximately one-half mile.

DEP will perform subsurface investigations at West Hurley Dike and Woodstock Dike in late September and October. This work will not require the Ashokan Rail Trail to be closed. However, because the work at Woodstock Dike is adjacent to a rail-trail parking lot, the work area will be cordoned off with fencing and visual barriers. Rail trail visitors are reminded that Woodstock Dike is not open to the public, except for fishermen who have their boats stored on two peninsulas near the dike.

DEP will perform subsurface investigations at Glenford Dike in early November. That portion of the Ashokan Rail Trail will be closed Monday through Friday for approximately 2-3 weeks to ensure the safety of workers and the public. That stretch of the trail will be re-opened each Friday evening, Saturday and Sunday. The work at Glenford Dike was specifically scheduled after peak foliage season to accommodate visitors at the trail.

In August, DEP will also gather subsurface information for the foundation of a new storage building near the Ben Nesin Office Building on Route 28A. These borings will take one week to complete and will happen in an area that is not accessible to the general public.

The Ashokan Century Program

The Ashokan Century Program is a comprehensive set of projects to upgrade practically all the infrastructure at Ashokan Reservoir, including the dam, dikes, chambers, spillway and the Dividing Weir Bridge. DEP has committed approximately $750 million to the program thus far. Some of the earliest work is expected to begin in 2023, and the program is expected to stretch well into the 2030s.

The Ashokan Century Program is part of DEP’s continuing efforts to upgrade dams and other key facilities that provide 1.1 billion gallons of drinking water every day to more than 9 million New Yorkers. That effort began nearly three decades ago. Beginning in the 1990s, DEP rehabilitated a number of dams that are part of its Croton Water Supply System in Putnam and Westchester counties. In 2014, DEP completed the $138 million full-scale rehabilitation of Gilboa Dam at Schoharie Reservoir.

About 40 percent of New York City’s drinking water passes through Ashokan Reservoir each day. It impounds 125 billion gallons of water at full capacity. The reservoir collects rainwater and melting snow from a 255-square-mile watershed that includes part of 11 towns in Ulster, Greene and Delaware counties. The reservoir conveys that drinking water to New York City through the 92-mile-long Catskill Aqueduct.

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 nyc.gov/dep, like us on Facebook, or follow us on Twitter.