The Kensico Dam, was completed in 1917 at a cost of more than $15,000,000.
The
dam is 1,825 feet long. It stands 307 feet above its foundation and
contains 1,000,000 cubic feet of masonry, as much masonry as the Egyptians used
to build some of the pyramids. In one month, 2.5 million cubic yards of concrete
were poured into blocks which had to cure for three months before being swung
onto the rising hyperbolic pile of the dam. The dam is able to hold back
about 30 billion gallons of water.
New York City’s main Kensico contractor built up a great work camp
at Valhalla for the 1,500 men who worked on the dam at the height of
construction. The Water Supply Board created a mounted police force to keep
order. Railroad tracks and overhead trams were built to reach Quarry Heights in
Harrison, where the rock for concrete was to be blasted out and crushed. Crews
were made up largely of Italian immigrants who began the long task of digging
straight down to a depth of 110 feet to reach solid rocks with no water-bearing
seams.
This entailed months of blasting and a number of fatal accidents. As the aqueduct neared completion in 1913, the work gangs at Kensico began laying the first of the concrete bricks of which the dam is built.
The tremendous influx of workers provided a period of prosperity for the entire area surrounding. New stores, rooming houses, hotels, restaurants and saloons met the needs of the workers and their families.
Many of the construction families remained in the area after completion of the dam, contributing to the growth and character of Valhalla and its environs.
