谢菲尔德供水系统
The Sheffield. England, water system consists of a series of high lying reservoirs which supply, entirely by gravitation, an extensive area, including a wide range of heights. The gathering grounds are elevations ranging from GOO to 1,400 feet, where the average rainfall is about 40 inches per annum. This water is impounded in 12 basins, formed by earthen embankments carried across the natural valleys, drain an area of 2,400 acres, and have a total capacity of six billion gallons. From these basins the water is conveyed along a water course and through trunk mains, varying in diameter from 15 to 24 inches, to service reservoirs within the city, some of which are high level, to feed the higher parts of the district, while others are low level, to supply the city proper. From these 12 reservoirs, of an aggregate capacity of 83 million gallons, between 12 and 16 million gallons of water per day, nearly one-half of which is for trade and manufacturing purposes. arc distributed throughout the city and district by means of 500 miles of pipes varying from 6 to 24 inches in diameter. The softness of the water make it pleasant to drink and satisfactory for general household purposes. For manufacturing and engineering purposes, it was found that its purity and softness makes it attack the inside of new lead piping. This, however, was overcome as follows: In a cement vat chalk and water are tlioroughly mixed by means of revolving fans, then the liquid discharged into the gauge basin, where it mixes with the water supply for the town. This apparatus is worked by a threethrow hydraulic ram under pressure of water from one of the higher reservoirs, at a cost of 2 cents for every 2,500 gallons of water treated. Such is the system of water supply evolved by the corporation in the 25 years that it has been operating. In 1888 the municipality took over the city’s water supply and paid $10,122,388 to a previously operating company. Since the iransfer $2,137,935 has been spent upon additional works and extenisons of mains. The working expenses in 1887 were 18.69 per cent, of the income, while those of 1913 were only 17.85 per cent., in spite of the fact that wages have increased during the interim by more than 70 per cent. In 1887 the income was $393,831; since then it has increased 169 per cent., amounting in 1913 to $1,113,S00. Growth of system is shown by the following figures: Houses supplied in 1887, 68,066; in 1913, 113,717. Population supplied In 1887, 313,903; in 1913, 489,927. Outside districts in 1887, 6,000; in 1913, 167,129. Gallons of water supplied (per day)—1887. 6,049,103; in 1913, 5,797,875.
