The 1906 Croton Dam is a marvel of engineering to rival the Great Wall of China and the Pyramids at Giza. I mean this literally. I have heard some claim that the Croton Dam is the largest hand-hewn structure on planet Earth. From an engineering standpoint the most striking feature is the sideways spillway. The dam is a majestic combination of engineering and civic beauty.
The 1842 Croton Dam was built on the Croton River to supply drinking water to Manhattan on a 41-mile underground aqueduct. This Dam was rapidly outgrown and would be replaced by a mammoth dam 1100 ft in length and 100 ft high, providing capacity of 30 billion gallons (a 100 day supply). Because the bedrock is at such a deep level, if the spillway had gone over the front of the dam, heavy flows would have undermined the dam footings. The clever solution was to create a sideways spillway, which dumps water down a massive set of stone steps, set 90 degrees to the dam's face, onto a seam of bedrock close to the surface. The 200-ft steel arch bridge was rebuilt in 1999 but was not re-opened based on 9/11 security concerns until 2005.
These pictures, ironically, were taken on September 11, 2011, just days after record rainfall from Tropical Storm Lee. The raging torrents were Niagara Falls-like, with a mesmerizing, if not scary, intensity.
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