Croton大坝和Jerome Park水库
迄今为止，这些伟大的作品取得了进展。
由于新英格兰水厂协会的大会将于下周在纽约市举行，因此将发现一些有关大都市供水的细节。It is needless to go back to the old days when wooden pipes formed the means of distribution and the old standpipe still in existence at Duane and Centre street of Aaron Burr’s and the Manhattan company’s time was the collecting medium for the waters of the Collect creek, still running under the Tombs to the North River. The need of a new source to supply the growing city was felt some years after that system had become practically useless, and the wooden reservoir (.the third built in New York), which was erected at Thirteenth street and Broadway—the supply being by pumping kept up by a steam pump—was really the beginning of the city's system of water supply. In 1835 the Croton river was chosen as the source of supply, and the Croton aqueduct commission was formed. The old Croton aqueduct reservoir was built some forty miles from the city, with an aqueduct—a masonry conduit—leading the water thence to One-hundred and thirtyfifth street. New York. Its capacity, when running full is 90,000,000 gallons in tw-enty-four heturs; its normal daily capacity is 75,000,000. It was completed in October. From One-hundred and thirty-fifth street the water is carried in four cast iron pipes—two thirty-six-inch, one forty-eight-inch, and one sixty-inch, crossing Manhattan valley to One-hundred and nineteenth street, where is another masonry conduit extending to One-hundred and thirteenth street, whence are laid pipes to the Central Park reservoirs— the fall being 48.06 feet. Through High bridge there are three pipes—two, cast iron, three feet in diameter, and one, wrought iron, seven feet six inches in diameter. The aqueduct internally is horseshoe-shaped, eight feet wide. The area is 53.34 square feet; normal daily capacity, 75.000.000 gallons; elevation of invert at Croton lake 155.0 feet—Croton datum—grade of aqueduct one foot per mile. In 1840 was built the first storage reservoir between Seventy-ninth and Eighty-sixth streets and Sixth and Seventh avenues—now in Central Park. Its overflowings fed the late distributing reservoir in Murry Hill and Forty-second street and Fifth avenue (first used in 1842). The new masonry aqueduct was built in 1890, almost in a straight line from the Croton reservoir to the Harlem river, which it crosses by a submerged masonry conduit to the gatehouse at One-hundred and thirty-fifth street. The length of the masonry conduit is 30.87 miles; capacity 300,000,000 gallons; cost, $20^000,000. Under the Harlem the aqueduct is 311.11 feet below city datum, depth of shaft No. 25 at the south side of the Harlem river, 402.5 feet. With the old aqueduct the submerged conduit discharges into a tunnel gatehouse at One-hundred and thirty-fifth street, whence the water is carried by eight forty-eight-inch mains to the citv. As the pressure from the reservoirs falls before they are emptied, and what water is left is insufficient to reach the higher flows even of buildings of ordinary height, the construction of the Jerome Park reservoir was determined upon. The new aqueduct involved the building of the new Croton dam, now practically completed and being gradually filled till the new lake is formed. Its water surface, when filled, will be 5,000 acres, as against the 840 acres of water surface in the Central Park reservoir. its length, when full, will be nineteen miles and one-half; average width half a mile; area, including the marginal lands, acres. 1 lie length of the dam proper (on which the work began on October 1. 1892). > -3.300 feet, including 1,000 feet of spillway; breadth at base, 206 feet; height from base to crest, 297 feet; foundations extend 130 feet below bed of the river, with the spillway. It contains 850,000 cubic yards of masonry; impounds 30,000,000.000 gallons; cost about $9,000,000. A steel bridge will be built across the spillway, to connect the driveway over the crest of the dam with the road that is being built along the bluffs on the north. The same below will be graded and sodded; graveled walks will be laid out; and a large fountain will be built.
