at the New-York Historical Society. Click the image to enlarge it.
This photograph of the nearly completed New Croton Dam gives us a look at the spillway without the usual cascade of water. Below are details from the image, showing the immense scale of the structure—made entirely of hand-hewn stone which was cut, moved and placed without the aid of modern construction equipment.
The image comes from the George P. Hall & Son Photograph Collection at the New-York Historical Society. According to NYHS, “the commercial photography firm . . . operated in Manhattan from 1886 through 1914. Working out of several studios, the firm documented the changing face of New York City at the turn of the 20th century. Hall & Son’s photographs were available for general sale, were published in their own calendars and souvenir viewbooks, and appeared as illustrations in such publications as King’s Views of New York, Staley’s Views of New York, and Harper’s Weekly.”
This is just one of the many treasures you can find at the New York Heritage Digital Collections website.
Click the image to enlarge it.
CROTON 
Great find for interesting Croton Dam pictures. I think the city stored all the water it could, so that even after the dam and series of storage reservoirs were complete, no water was released over the dam during drought periods as long as there was additional storage capacity to be filled. Environmental concerns eventually mandated a constant release over the spillway, not sure at what date.