AQUEDUCT 



307 



AQUEDUCT 



the Middle Ages the construction of aqueducts 

 almost completely ceased, but with the Renais- 



A X AQUEDUCT OF NERO 



sance came a new development. The Popes 



at Rome restored some of the ancient struc- 



whirh had fallen into disuse, and several 



new ones were built in France. One of the 



most remarkable of these was begun by Louis 



in 1684 to cany water from the Eure 



River to Versailles. Forty thousand soldiers 



worked four years on this task, which was 



never completed because war broke out in 



1688. Most ancient aqueducts were of stone, 



or of brick and concrete, but the extensive use 



ton and steel pipes has now rendered the 



construction of aqueducts of the old type 



cessary. Gravity is now frequently aided 



by pressure, and the aqueduct bridges are 



usually v rtcd siphons (see 



SIPHON). The bridge form, however, is still 



used not only for supplying water to towns, 



:!<() III II! <'tS. 



One of tin :i:-t of the great aqueducts built 

 by European cities was that from Loch Km 

 1 ilasgow, completed in 1860. Manchester, 

 l.md, is supplied by an aqueduct, com- 

 pleted in 1892, nearly ninety-six miles long. 



I. -nutli tl miles air 



conduit, fourteen and one-half miles of con- 

 tunnels, and i - of iron pipe. 

 Paris and many other cities 

 !<>ng aqueducts. 



Croton Aqueduct. In the United States the 

 first important aqueduct was the old Croton, 

 completed by New York City in 1842. Boston, 

 Brooklyn, Baltimore, Washington and Saint 

 Louis followed in order. New York, as the 

 largest city in America, has the greatest prob- 

 lems in connection with its water supply. The 

 Old Croton Aqueduct has a total length of 

 thirty-eight miles and an average fall of one 

 foot per mile. For most of its length it i< 

 constructed of stone, brick and cement. The 

 water is carried across the Harlem River in 

 three iron pipes, the largest having a diameter 

 of seven and one-half feet. It was designed 

 to carry 72,000,000 gallons a day, but was soon 

 found to be too small for the needs of the 

 city. Minor changes were made from time to 

 time to increase the flow, until in 1890 the 

 New Croton Aqueduct was completed. The 

 new one, like the old, begins at Croton Lake, an 

 artificial body created by damming the Croton 

 River, and runs to 135th Street, where it is 

 connected with the city's distributing system. 

 It passes the Harlem River by an inverted 

 siphon 300 feet below the river bed. For 

 most of its length it is a horseshoe-shaped 

 tunnel thirteen and one-half feet high and 

 an inch or two wider. Its original carrying 

 capacity was over 300,000,000 gallons a day, 

 but its average flow, because of wear on the 

 interior, is now only 250,000,000 gallons. 



Catskill Aqueduct. This great project, begun 

 in 1906 and practically completed in 1913, will 

 eventually add 500,000,000 gallons a day to 

 New York's water supply. From its beginning 

 in the Catskill Mountains to the end of the 

 aqueduct proper is a distance of ninety-two 

 miles, and pipe lines and branches in the city 

 add thirty-four miles more. The water is 

 taken from several rivers in the mountains 

 and is collected and stored in the great 

 Ashokan reservoir, thirteen miles west of 

 :ston, N. V. The reservoir is twelve miles 

 long by one mile wide, with :i maximum depth 

 of 190 feet. Two smaller reservoirs are re- 

 spectively thirty and fifteen miles from 

 the New York Municipal Building. The ini- 

 < upacity of the system is 250,000,000 gallons 

 a day, but by 1920, when several additional 

 secondary reservoirs will be completed, this 

 will be doubled. 



Most of the aqueduct was built by tho "cut- 

 and-covcr" method; that is, excavations were 

 made, the aqueduct was built in the opening, 

 and the earth was then replaced. Fifty-five 

 were constructed in this way, and thirty- 



