Croton Dam - an engineering wonder of the world

2024 Author: Seth Attwood | [email protected]. Last modified: 2023-12-16 15:55

There are quite a few attractions in New York that may surprise even the most seasoned traveler, but for some reason it was this object that impressed me the most. Surprisingly, it turned out to be not one of the famous New York skyscrapers or bridges, and indeed, this structure is located outside the city, although it is part of its life support system. This is a real engineering miracle, created by human hands at the turn of the 19th and 20th centuries, the look and scale of which is breathtaking.

With this post, I begin a series of stories about the amazing Croton system, which has been supplying New Yorkers with clean drinking water for over a century. The water supply system, which radically changed life in the city, helped to get rid of dirt on the streets, defeat numerous fires and epidemics, and significantly improved the quality of life of its citizens. Today I will talk about the Croton Dam, which is 35 km away. north of the city and was once one of the key links in this system. Without its construction, everything else would have been impossible, and New York would never have become the city as we know it now.

The first structure to supply clean water to New York was a dam, now called Old Crotonsoca. Its construction lasted from 1837 to 1842, and it was the first masonry dam erected in the United States. By 1881, after numerous repairs and improvements, the dam was supplying 340,000 cubic meters of water to New York every day. The water flowed into the city along a specially built underground Croton aqueduct with a length of 66 kilometers, about which there will be a separate post. In 1885, in connection with the sharply increased needs of the city for clean water, a special city commission decided to build a new drainage structure in the same area, and to build another aqueduct to deliver it. According to the developed project, a new dam should be erected at 6.5 km downstream of the Croton River, as a result of the construction of which a vast reservoir will be formed, and the supply of water to the city will increase to 1 million cubic meters per day.

3. Croton River before and after the construction of the dam. Illustration from Scientific American magazine, 1891. The old dam fell into the flood zone and now only its upper part is visible from the water.

The winning bidder was James Coleman, head of New York City's Street Cleaning Department, who had extensive experience in road and tunnel construction. The legislation of that time did not prohibit the combination of public office and running one's own business, even if the commercial interests in this matter were quite obvious. Under the contract, he undertook to build the dam in five years, for which he received from the city budget a fantastic amount at that time of 4,150,573 dollars. Initially, the project involved the construction of a dam two kilometers lower, closer to the present town of Croton-on-Hudson, where the rock is almost close to the surface, but the project caused such a wave of indignation and protests from local residents that it had to be moved higher. About 50 square kilometers of land fell into the flooded area of the reservoir, on which numerous residential buildings, farms, schools, churches and cemeteries were located. After a long and dreary land acquisition procedure, which was accompanied by countless violations, scandals and legal proceedings, after the resettlement of people and the transfer of homes and even the dead from cemeteries, work finally began in 1892.

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photo by NYPL

The chief engineer of the project was Alphonse Faley, little known then and now. He designed a structure completely unique for its time, which, even more than a hundred years later, amazes with its scale and design. One can only imagine what the reaction of contemporaries was, because at the time of construction, the New Croton Dam was the tallest in the world, was the world's largest structure made of stone and was the third largest structure on earth built by human hands, after the Great Wall of China and the Egyptian pyramids.

5. Comparison of the New Croton Dam with the Fuller Building, now known as the Iron. The white line shows the foundation of the structure.

The new site was not as successful from an engineering point of view as the one chosen initially, and many problems had to be solved here, including digging a huge pit 40 meters deep in order to reach the rock on which the construction of the foundation could begin. The dam was built using masonry technology, the volume of which is 650,000 cubic meters. The stones were connected with cement mortar.

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photo by NYC Municipal archive

The material used was granite, which was mined in quarries near Hunterbrook, and then delivered to the construction site along specially constructed railway lines. At the construction site itself, a miniature railway was built, along which steam excavators drove, the selected rock was transported on small trains and stones were delivered.

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photo by NYC Municipal archive

8. Massive blocks weighing 2 tons each were moved using cranes built on the principle of a cable car. To supply steam, a small plant for its production was specially built nearby.

The second unique solution was the construction of the weir, which was risky to equip in the middle part of the dam due to the danger of its destruction. The discharge capacity of the spillway is not regulated and depends only on the water level in the reservoir. Masonry is not as reliable as reinforced concrete; it can simply erode when the water pressure increases. There was no great experience in creating such structures then and many things had to be invented on the go. Faley chose an elegant and original solution that gives the dam such an unusual look. The spillway was made in the left part of it, and for its arrangement, the terrain and its drop in this place were correctly used. It turned out something like a small channel, starting at the very mirror of the water and increasing its depth as it approaches the dam wall. It was he who gave the refractive effect, which was in the photo from my question post. This solution made it possible to reduce the load on the structure, especially during floods or in the case of a sharp increase in the water level in the reservoir. As time has shown, this decision was chosen and executed brilliantly.

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photo by NYC Municipal archive

Another, in its own way, unique solution was to attract teams of stonecutters from the south of Italy. They were taken by steamer to New York, where they were given $ 25 each to go ashore (without the money they would simply not have been allowed to America). Around the corner, the money was taken from them, the masons themselves were put on a train and sent to a construction site, where they were settled in barracks specially built for them. In America, there was simply not the right number of specialists for the construction of such a large-scale structure.

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photo by NYC Municipal archive

Italians were also cheaper, which lowered costs and increased profits. For a 10-hour day of hard physical labor, they received $ 1 30 cents, while the average American worker received 22 cents an hour. Harsh working conditions and low pay led to a strike in April 1900. As a result, the pay was raised slightly, the strike itself was suppressed with the help of cavalry, and its organizers were arrested and brought to justice. They even made a black and white silent film called "The Croton Dam Strike" on these events.

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photo by NYC Municipal archive

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photo by NYC Municipal archive

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photo by NYC Municipal archive

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photo by NYC Municipal archive

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photo by NYC Municipal archive

sixteen. Territory of future flooding.

photo by NYC Municipal archive

The construction of the dam required changing the river bed and draining its old bottom. For this, a bypass channel 300 meters long and 61 meters wide was dug in the form of a crescent, the ends of which entered the old channel. There was not enough space for its construction and it was necessary to bite into the rock from the northern side of the future dam. During the construction of the canal, a protective wall and several dams were installed to control the water level. The work continued day and night all year round and was stopped only a few times during very severe frosts. In winter, the blocks were steamed and salt was added to the solution. The main construction work took 8 years. Six more were needed for numerous modifications, additions and repairs. It is officially believed that the dam was completed in 1906. In fact, it was completed and improved for many more years. The final cost of its construction was $ 7.7 million.

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photo by NYC Municipal archive

In those days, the beauty and grace of even such a specific structure as a dam were valued no less, and perhaps even more than its functionality. Any such object automatically became a place of attraction for tourists from all over the country and had to meet the requirements of the most picky public, who flocked in large numbers to look at the latest achievement in engineering, to sit in the noise and splashes of falling water to reflect on the imminent triumph of progress. News of the construction continued on the front pages of newspapers, and detailed diagrams depicting the construction of the dam adorned the pages of specialized magazines. Therefore, the dam is not only unique from an engineering point of view, but also simply beautiful. It was intended to become a symbol of the achievements of the North American states around the world, and to show that the Americans are capable of solving problems of any complexity. People only just curbed the steam engine, did not really have production equipment and machinery, and were already ready to turn the rivers back. Scientific American wrote in 1905 - "This noble structure will represent one of the most impressive and beautiful engineering solutions, and will testify to our achievements around the world."

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photo by NYPL

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photo by NYC Municipal archive

20. The dam is 91 meters high from base to ridge. The total length with a weir is 667 meters.

21. In front of it there is a fountain that is not functioning now.

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23. One of two stairs leading inside.

24. All doors are securely walled up.

25. When trying to see what was inside, I saw only old beer cans and bottles.

26. The dam periodically gives insignificant leaks. White marks are smudges from the solution on which the stones sit.

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28. Spillway.

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30. Directly in front of the dam there is a bridge from which it is convenient to take pictures.

31. View downstream of the river.

32. A motor road runs along the ridge, traffic on which was limited after the tragedy of September 11th. Now it is occasionally used by special service vehicles and by a few tourists who come here for a walk.

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35. Entrance to the dam.

36. Weir making it look a little unreal.

37. Downward view.

38. The road going along the dam.

39. Entrance to the technical room.

40. The metal bridge has already been overhauled several times. The last time it was in 2005.

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43. Reservoir.

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45. Entrance to the dam from the other side.

46. Water in the reservoir.

New Croton is jokingly considered a mixture of Niagara Falls with Hoover Dam. And she really surprisingly combined the properties and external features of these two truly amazing objects, only on a slightly reduced scale. Another feature of the dam is its lack of popularity as a tourist destination. Despite the proximity to the city, gorgeous views and the uniqueness of the structure, not all New Yorkers know about the Croton Dam. I'm more than sure that some of my New York readers have never even heard of it, although it is less than an hour's drive from Manhattan. It is difficult to say why this happened, but the fact remains that many people still have to discover this working monument of engineering thought of the early 20th century.

Video for completeness.