The Shawangunk Tunnels

Over the last two centuries a number of proposals have been made to bore tunnels through the Shawangunk Mountains. These mountains were a significant barrier between the Hudson River valley and New York City on the east and the economically important New York Catskill and Pennsylvania Pocono Mountains to the west. However, in all this time only three tunnels have been dug. These tunnels have been at the forefront of 19th and early 20th century technology and offer a window into a fascinating part of our industrial infrastructure. We’ll examine these efforts and, in the process, discover some of the unique challenges that the Shawangunk Mountains posed to engineers and construction crews.

When the route for the D&H Canal was being planned in the 1820’s a group of Orange County businessmen lobbied for the canal to cross Orange County. In 1825 these gentlemen proposed that a tunnel be dug through the Shawangunk ridge and that a canal be built through Orange County to Newburgh where it would join the Hudson River. Since one of the strong backers of the D&H Canal was George Duncan Wickham, one of Orange County’s most prominent citizens and a member of the D&H Board, the D&H Board of Managers had to treat the proposal seriously. Wickham made a motion to the Board to explore alternatives to the Kingston route and the Board approved.

Benjamin Wright, the nation’s foremost canal engineer was asked to explore alternatives to the Kingston route. Wright evaluated the proposed Orange County route and determined that a tunnel two miles long would be needed and that the additional cost would be prohibitive. It’s worth noting that with the black powder blasting technology available at the time, digging the tunnel would surely have delayed the completion of the canal well beyond the actual completion date of 1828 when the canal was opened to Kingston.

Ten years after Wright rejected the idea of a D&H Canal tunnel he had to consider the idea of a Shawangunk tunnel again. Wright had become the chief engineer for the Erie Railroad and had to consider whether the Shawangunks should be crossed by the Erie at Otisville by going over the top or through a tunnel. He opted for a series of relatively steep rock cuts over the Deerpark gap at the summit of the mountain between Otisville and Cuddebackville in the route plan he completed in 1835. He did not support the idea of a tunnel at the time since the amount of traffic expected could not justify the expense of a tunnel he estimated would have to be over half a mile long. He did state in his report to the New York Secretary of State that in 20 years time the increase in the railroad’s business would demand that such a tunnel be built. In 1847 the railroad finally accepted Wright’s recommendation and built the line. Though in 1873 the railroad re-considered its decision on building a tunnel, nothing came of that effort.

It was more than 20 years after the Erie rejected the idea of a tunnel but in 1868 Clinton Stephens designed a tunnel through the Shawangunk ridge between Wurtsboro and Bloomingburg for the rival O&W Railroad. Stephens had previously won large contracts for the Erie Canal enlargement and for the construction of the Erie Railroad. He would later go on to work on the New York City and Washington, DC aqueduct systems building reservoirs, roads, and tunnels. He would also become the engineer for the Tilly Foster Iron Mine in Putnam County, New York which shipped large amounts of iron ore to Scranton, Pennsylvania for use in the manufacture of steel rails for the railroads.

This was the first tunnel through the Shawangunk Mountains. Construction of the O&W tunnel began in 1868 and was completed in 1871.Work was started at both ends of the tunnel simultaneously. When both teams met in the middle they were only a few feet off. This was quite an engineering feat at the time, especially since the tunnel was curved. The tunnel was 3,857 feet long and was cut through solid rock. It was made possible by the invention of dyna-

mite in 1866 by Alfred Nobel and by the availability of steam-powered drills. Dynamite was a boon to construction projects since it was a great deal more powerful than black powder and much safer that nitroglycerin. Using dynamite ensured that the tunnel would be completed in a reasonable amount of time.

The O&W was constantly struggling against water problems and falling rock in the Shawangunk tunnel. The mountain where the tunnel is located is composed of Shawangunk grit. This was at the core of the problems the O&W was having. Shawangunk grit is a silica-cemented conglomerate of quartz pebbles and is very hard and abrasive making it one of the best materials for mill stones. It is also waterproof and its deposits are riven with open seams and fractures which are ideal channels for water.

The idea of an Erie Railroad tunnel at Otisville lay dormant until 1906 when work finally began on the long awaited tunnel. Troubles beset the tunnel builders as they worked their way through the mountain in 1906. In August fighting broke out within the African-American crew that was digging the tunnel. The local Justice of the Peace and his constables had to be summoned to restore order. This sort of thing wasn’t anything new, however. In 1847 when the tracks were first being laid, fighting broke out between Irish gangs and between the Irish and German communities. The militia had to be called in to quell the violence then.

In September a blast of the explosives being used to excavate the tunnel caused the tunnel roof to collapse killing one workman and trapping a number of others. The Shawangunk grit that the tunnel bored through likely contributed to this tragedy. That same month it was reported that the new tunnel was causing local water veins to dry up. This caused farmers’ wells to run dry and for large amounts of water to spill into the tunnel. This was surely an effect of the Shawangunk grit.

Planning for the third Shawangunk Mountains tunnel was finished in 1908. New York City was planning a massive project to bring down water from the Catskill Mountains and a 7,350 foot tunnel bored under the Shawangunk ridge near High Falls at Bonticou Crag was included in the project plans. The planners were very well aware of the problems with Shawangunk grit, especially for water tunnels. They specified that the conglomerate should be avoided as much as possible due to the expense of boring through such hard rock as well as the risk of water leaking from the aqueduct. Work started from each end of the tunnel in 1908 and was completed in 1910.

The Bonticou Crag tunnel was a small but significant part of the much larger Catskills Aqueduct whose full length was about 120 miles. Active work on the project started in 1907 and by late 1915 water was being delivered to parts of New York City from the Catskills reservoirs. At one time over 17,000 men had been working simultaneously on the aqueduct from one end to the other. A large proportion of these workmen were Italian. Many learned to read and write English whilst working on the aqueduct at schools funded by private philanthropy.

In 1917, the aqueduct’s completion was formally celebrated. The aqueduct was built to be able to supply half a billion gallons of Catskill water to New York City every day. Its final cost was 176 million dollars for the entire project. It has been over 100 years since the aqueduct was started and it still plays a vital role in the life of the city. Certainly, the city’s growth would have been seriously hampered without the Catskill water carried down the aqueduct and through the Shawangunk tunnel for delivery to New York City.

Copyright 2009 by Stephen Skye

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