سد كروتون Croton الجديد على نهر كروتون

سد كروتون Croton الجديد على نهر كروتون



سد كروتون الجديد الذى يوجد على نهر كروتون ، بالقرب من كروتوني على بعد 35 كم من مدينة نيويورك انشأ لتحويل المياه من نهر كروتون في كروتوني الى الخزان الجديد الذي يوفر المياه لسكان مدينة نيويورك وكان هذا أول نظام إمدادات مياه رئيسية للمدينة الخزان impounds يستوعب حوالي 19 مليار غالون من الماء الآن جزءا صغيرا من إجمالي السعة التخزينية شبكة المياه في مدينة نيويورك هى 580 مليار جالون تم بناء كروتوني القديم الأصلي في 1842 وكان الخزان القديم بقدرة على توفير حوالي 90 مليون جالون من المياه يوميا إلى المدينة خلال 66 كم فى قناة تحت الأرض وبحلول نهاية القرن ال19 ، أصبح من الواضح أن مدينة نيويورك بحاجة إلى المزيد من المياه ونتيجة لذلك ، بدأ العمل على سد كروتوني الجديد.
































New York's New Croton Dam An Engineering Wonder
The New Croton Dam is an impressive display of engineering and nature in Cortlandt Manor, Westchester County, New York. The spillway of the dam forms a beautiful waterfall in Croton Gorge Park, which features sledding hills, winding trails, and picnic areas for visitors.
The New Croton Dam is an impressive display of engineering and nature in… (Bettina Hansen, bhansen@courant.com )
February 08, 2012|By ERIK OFGANG, Special To The Courant, The Hartford Courant
The New Croton Dam might be one of the coolest places you've never been.

Located in Croton Gorge Park in Cortlandt Manor, N.Y., it was completed in 1906 (the term "new" in its name is relative). The dam is among the most impressive man-made structures in the Northeast and boasts a majestic waterfall-like spillway, a sprawling retaining wall and an aerial bridge that offers a close-up view of the dam's rushing torrents. It's also said to be the third largest hand-hewn structure in the world, trailing only the Great Pyramid of Giza and the Great Wall of China. Yet outside of those who live and work in or near Cortlandt Manor and engineering history buffs, relatively few people even know about its existence.

I grew up less than an hour's drive from the New Croton Dam in northwestern Westchester County, but never heard of it until a few years ago. A friend and local history buff, Bill Gillespie, told me about it and urged me to check it out. My first trip to the park took place two years ago, and I've been back many times since; most recently on an unseasonably warm day in early January.

The structure brings to mind both Niagara Falls and the Hoover Dam, albeit on a slightly smaller scale. The dam's spillway is unusual in that it is located to the side of the retaining wall and is partly natural and partly man-made. Water flows down the natural portion in wild waterfall-like rapids, while at the man-made portion water spills down huge steps, creating a spectacle that looks like a giant wedding-cake-shaped water fountain.

The original Old Croton Dam was built in 1842 across the Croton River. It brought water to Manhattan through a 41-mile underground aqueduct. By the 1880s it was clear New York City needed more water and plans were made to harness water from the Croton River's three branches with a new dam. To build it, a 20-square-mile area of land was needed and dozens of schools, dwellings, barns and churches were condemned. In addition, the residents of four towns had to move and 1,500 bodies in six cemeteries had to be dug up and relocated.

Construction on the New Croton Dam began in the early 1890s. Engineers originally planned to build the dam a mile downstream where the bedrock was closer to the surface. Local protests forced the project to be moved to a location where the bedrock was at a much deeper level. As a result the dam's engineer, Alphonse Fteley, had to dig down 131 feet to find bedrock. If the spillway had gone over the front of the dam, the water might have damaged the dam's footings. To overcome this problem Fteley devised the unusual sideway spillway, which helps make the dam's appearance so unique.

Many of the workers who built the dam were stone masons from southern Italy. They earned wages of just $1.25 or $1.30 for a 10-hour workday. Not surprisingly, the workers were not always happy with the meager pay. There was a strike at the dam on April 1, 1900, and the National Guard had to be brought in to restore order.

The dam was designed not only for function but for form as well. Scientific American wrote in 1905 that "this noble structure will form one of the most impressive and beautiful scenes, of an engineering character, to be witnessed in any part of the world."

That beauty is still visible today. From the base of the dam you can get close enough to the spillway to feel drops of water on your hair and listen to the falling waters roar, which is loud enough to drown out all but the most annoying of cellphone ring tones You also can walk right up to the retaining wall and feel like the smallest of ants in its massive shadow. On the south side of the park there's a path that goes up to the top of the dam and a bridge that crosses over the spillway. From the bridge you can gaze at the reservoir on one side, a steep drop on the other side and the dam's spillway below, which often forms rainbows that seem only feet away.

Until recently the road across the top of the dam was open to cars, but in 1999 New York City's Department of Environmental Protection, which supervises the city's water supply, closed the bridge for repairs. After the Sept. 11, 2001, terrorist attacks, the road was kept closed because of security concerns. The dam also was guarded during World War I and II.

In addition to the dam itself, the Croton Gorge Park is a 97-acre retreat with giant grass fields, a small playground, picnic tables and hiking trails. New York state's Old Croton Aqueduct Trail starts at the park and follows the old underground aqueduct about 40 miles to New York City, although there are breaks in the trail along the way.

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