Last Friday, the NYC Department of Environmental Protection [DEP] held a press conference to announce that tunneling will soon begin on a 2.5 mile bypass tunnel that will run 600 feet under the Hudson River from Newburgh to Wappingers Falls in order to stop leaks in the 85-mile Delaware Aqueduct. The project may cost up to $1.5 billion and is the largest repair undertaking in the 175-year history of the NYC water supply system. The design will fix two segments along the 70 year old aqueduct that have been leaking for decades – in the towns of Warwarsing and Newburgh. Engineers estimate the loss of water at 20 million gallons per day, with 95% of that occurring at the Newburgh location near the Roseton Power plant. This was first detected in 1992 and by 2014 a small self-propelled submarine-shaped vehicle was employed along a 45 mile stretch of the aqueduct between the Rondout and West Branch Reservoirs to definitively locate, measure and map the leaks using sonar, velocity and pressure data. The results confirmed the location of the leaks and that the cracks have not progressed further.
This second phase of the tunnel project will use a state of the art boring machine that measures 470 feet in length – including a 21 foot diameter cutting head, body and trailing gear – and weighs 2.7 million pounds. It has been dedicated in honor of Nora Stanton Barney [1883-1971], a noted activist and granddaughter of suffragette Elizabeth Cady Stanton, and the first woman in the U. S. to earn a college degree in Civil Engineering from Cornell University, graduating cum laude, Class of 1905. She also worked as a draftsman on the NYC’s first reservoir and aqueduct in the Catskill Mountains and also holds the distinction of being the first female member of the American Society of Civil Engineers.
This week construction workers will lower the cutting head into a large chamber staging area that was dug down to 845 feet below the surface. Once attached and in operation it will take approximately 20 months to tunnel under the Hudson River to Wappingers Falls. The work will take place around the clock and will drive 50 feet per day. The finished 14 foot diameter tunnel will have 9,200 feet of steel reinforcement and another layer of concrete to ensure there will be no leaks.
Once across the Hudson River the DEP will shut down the Delaware Aqueduct for six months, starting in October 2022 to connect the new bypass tunnel to the existing aqueduct. The agency is expecting to complete the project in 2023. The old leaking section will be plugged and removed from service.
The DEP manages the water supply for New York City, which brings 1 billion gallons daily to 9.5 million residents. The system also provides 110 million gallons of water daily to 70 communities in Orange, Putnam, Ulster and Westchester counties.
At the press conference DEP Acting Commissioner Vincent Sapienza said in the last 7 years the idea and design of a parallel tunnel across the Hudson River was developed. He called this an amazing project that will fix an age old problem along the aqueduct.
Coline Jenkins thanked the DEP for naming the boring machine in honor of her grandmother Nora Stanton Barney.
“We embrace Nora, the machine, as a member of our family as she will follow family tradition of ground-breaking,” Jenkins said. “My grandmother broke ground for women in Civil Engineering and she campaigned for woman’s right to vote and later worked for the Equal Rights Amendment, which we are still fighting for. Nora was an indomitable force and at times she was called a hurricane…She met challenges head-on and relished the challenge of overcoming obstacles. All of us who are attracted to Nora, the machine, must never forget the rallying cry of the women’s suffrage movement, failure is impossible. Our cause is critical to millions of Americans, whether the cause is to supply women’s rights or the cause is to supply clean drinking water to millions of Americans; all of this is critical to civilization.”
Nora Stanton Barney’s great-grandson Eric Jenkins-Sahlin said “although events like this are symbolic they are a big source of inspiration that we can draw from and public recognition of women’s work and contributions to important projects I think is moving the ball forward. There really is a lot to celebrate today.”
DEP Deputy Commissioner Paul Rush said there is limestone in the areas of Warwarsing and Newbugh that made these more susceptible to leakage. Since shutting the aqueduct down for up to four years was not an option, engineers thought of approaching the problem using a ‘fix-a-flat’ technique to fill the cracks. This proved to not work and eventually the solution of building a bypass parallel tunnel across the Hudson was developed and finalized. A drainage tunnel is also part of the solution to avoid having to shut the aqueduct down completely, especially during the time when the bypass is connected on the Wappingers Falls side. The leaking older tunnel is about 1,000 feet north of the bypass one that is under construction.
“Now we have a plan where we can deliver water to New York City, repair this vital tunnel and make sure the risk to the supply is manageable,” he said.
Rush said during the 6 month shutdown of the aqueduct Newburgh and Marlborough will be tapping water from the Catskill Aqueduct and Chadwick Lake.
By Mark Reynolds