Engineering Wonders of the World
Volume III

100 ENGINEERING WONDERS OF THE WORLD. ANOTHER VIEW OF THE SPILLWAY, NEW CROTON DAM, SHOWING THE CHANNEL WHICH LEADS OFF THE SURPLUS WATER. it there was to be an aqueduct, 12 feet in diameter, passing under the Harlem River and Manhattan Valley. This aqueduct, begun in January 1885 and completed in July 1890, consists of three parts : a masonry conduit, nearly 24 miles long, from Croton Lake to a great receiving reservoir of 1,900,000,OOOgallons at Jerome Park ; a masonry conduit under pressure thence for a further distance of nearly 7 miles to a gatehouse near Amsterdam Avenue ; and a pipe line from this point to the receiving reservoir in what is now th© heart of the city at Central Park. (See map on page 98.) Of the masonry sections of the conduit, 29J miles are constructed in tunnel. For blasting, exclusive of the quantity used in sinking the shafts, over 5,800,000 lbs. of dynamite were employed; and for lining the tunnel some 163,000,000 bricks were required. At the public hearings held by the Aqueduct Commissioners in 1883 and 1884 for the dis- cussion of the proposed plans, considerable opposition was manifested to the construction of the Quaker Bridge Dam, which was to be 100 feet higher than the highest masonry dam then existing. Consequently, it was not until 1892 that the contract for this part of the scheme was awarded. In the meanwhile, however, to satisfy the popular demand for “ more water at once—or sooner,” the Com- missioners and Department of Public Works proceeded with the construction of a number