There are four pumping stations located at the respective wells, with five Cornish and five Bolton and Watts’ condensing engines. Four pumping stations have been abandoned on account of the pollution in well water. Part of the town is supplied directly from mains and partly from cisterns. It is now compulsory for all new property to be provided with cisterns, and that the overflow-pipe be carried outside the premises instead of being connected to soil-pipe or sewer. A special staff of men is employed to make house-to-house inspection of all water fittings and appliances. The cost of the water-works was about 10 million dollars, and is inadequate. They are now constructing an artificial lake, 1 mile wide by 5 miles long, for impounding the waters of the Vyrnwy River in North Wales, 780 feet above the sea level, and 67 miles distant from the city. The area of water-shed is 22,000 acres. The dam will be a masonry structure, 120 feet extreme depth, and 100 feet wide at base; storage capacity, 1,900 million gallons. The cost is estimated at $15,000,000, and daily capacity 52 million gallons.
Glasgow.—The present water system was commenced in 1856, and completed in 1859, after the designs of Mr. J. F. Bateman, civil engineer. The supply is taken from Loch Katrine, including Lochs Drunkie and Vennachar, with a drainage area of 47,800 acres, and a storage capacity of 1,455 million cubic feet. The total length of aqueduct is 25¾ miles, of which 13 are tunneled, 3¾ of iron pipe across valleys, and remaining 9 miles of open cuttings and bridges. There are 80 distinct tunnels. The capacity of aqueduct is 50 million gallons per twenty-four hours. The amount required for compensation purposes is fixed at 40½ million gallons daily, to be discharged into the River Teith. The cost of the works was 6 million dollars. The water is exceptionally soft, being less than one degree.
Manchester.—The new supply was commenced in 1848, designed by Mr. J. F. Bateman, civil engineer. The source is in the counties of Derby and Chester, 777 feet above city datum. There are thirteen storage and distributing reservoirs, with a water surface of 975½ acres, and capacity of 6,458 million gallons. The greatest depth of reservoirs is 84 feet. The conduit is 18 miles in length. The drainage area is 19,300 acres. Available daily supply is 33 million gallons, of which 13 millions are required for mill-owners. The average rain-fall is 50 inches, and mean available resource of 33 inches. The cost of the works was 4 million dollars. The population in 1874 was 750,000; daily average consumption 16 million gallons, and 550 miles of pipe.
Edinburgh derives its supply from springs and brooks flowing from the northern slope of the Pentland Mountains. The water is collected in storage reservoirs, with a capacity of 280 million cubic feet, three of which are compensating reservoirs for mill-owners. The conduit is 8 miles in length, and varies from 20 to 15 inches in diameter. The water is distributed directly into mains with an equalizing cistern on the Castle Hill, 225 feet below the source of supply, and 332 feet above tide. The capacity of pipe is 253 cubic feet per minute. There were three filter-beds (in 1868) a short distance below the reservoir embankment. The sand surface of each is 90 by 90 feet. The superficial area of the three filters, 24,300 square feet; maximum rate of filtration, 85½ U. S. gallons per square foot per diem. The spring water is not filtered. The additional works were completed in 1868, which increased the supply to 992 cubic feet per minute, or 10,685,770 U. S. gallons per day.
Dublin secures its water supply from the Vartry River, 24½ miles distant from city, and 692 feet above low water at Dublin. The area of water-shed is 14,084 acres; the storage capacity, 2,400 million gallons. The water is conveyed through a 33-inch cast-iron pipe (with an average fall of 20 feet to the mile) to the Stillogram distributing reservoir. There are three receiving tanks on the line, with self-acting valves to shut off the water in case of pipe bursting. The distributing reservoirs contain 86 million gallons—are 230 feet above the average head of the city, and 4½ miles distant. Two 27-inch pipes distribute the water to the city from this point. There were seven filter-beds in 1875, each 215 feet and 115 feet at the top and 187 feet by 89 feet at the bottom, and 10 feet deep. The filtering material is 6½ feet deep, composed of 2½ feet 4-inch stone, 2 feet gravel, and 2½ feet washed sand. The head on filter-bed was increased from 2 to 3 feet to secure larger supply. The total cost of this new supply was 3 million dollars. The water-rate taxation is 26½d. per pound. The population in 1875 was 330,000; daily average consumption, 14 million gallons. All plumber fittings must be inspected and stamped, for which a fee of two cents is charged. This consumption, by careful inspection, was reduced from 19 millions. The largest annual rain-fall from 1861 to 1874 was 69.34 inches; minimum, 40.08 inches. Fifteen inches is allowed for evaporation, leaving 25 inches for available supply for the dryest year during this period.
Berlin.—The water department is owned by an English company, called the Berlin Water Company, who have had the exclusive privilege of supplying filtered water as required by the contracts since 1856. After 1881 the Government has the option of taking stock, and should the dividends exceed 10 per cent., one-half of the surplus is to go to the sewerage fund for the proposed sewers.
The water is derived mainly from the River Spree, through a canal reaching to the middle of the river. The pumping station is one mile outside of the city, in which are located eight double pumping engines, each pair having two beams, two pumps, and one fly-wheel. The first four engines erected have pump-barrels of unequal diameter and stroke, being respectively, 38 and 21½ inches diameter and 32 and 36 inches stroke. The large barrel was originally used for the delivery of the river water to the filter-beds under a pressure not exceeding 20 feet; the small barrel delivered the filtered water into the city under a varying pressure of 90 to 120 feet. As now operated, the four oldest engines pump the river water into the settling or storage basin before filtration; while the other four deliver the filtered water directly into the city mains, but the pressure is regulated by a reservoir and stand-pipe along-side of it. The stand-pipe is double-legged, connected at four points, each connection having a valve, except the highest. The highest connection is 200 feet above the pump-house, the lowest about 115, with others intermediate. The water of the small reservoir, when full, stands at about 110 feet above the pump well. There were eleven filters in 1875, with an area of 400,000 square feet. During the summer only eight of the beds are used effectually. They are cleaned in winter every month, and every week in summer. One-half of the old sand is replaced each time of cleansing with new sand. The average rate of filtration is 90 gallons per square foot, and maximum rate 120 gallons per square foot per twenty-four hours.
The filtering materials consist of 24 inches sharp sand, 3 inches of coarse sand, three courses, each 6 inches in depth, of gravel, of the size of a pea, hazelnut, and walnut, and 9 inches of granite pieces. The head of water on filter is 39 inches.
Frequently the river water is pumped directly into the filter-beds without subsidence. The stream is very sluggish in its velocity, being held back by locks for the purpose of navigation, the water does not carry sufficient sediment to render subsidence a necessity. There are, besides, certain lakes not far above the works through which the river flows, that are effective settling basins. They, however, communicate to the water a dark vegetable tinge.
The statistics for 1875 were: Population, 969,000; daily average consumption, 12¼ million gallons; number of meters, 6,916. Water-rent receipts, for 1875, were $600,000 or 13½ cents per thousand gallons, and expenses were $376,000, or 8 cents per thousand gallons.