Page:Encyclopædia Britannica, Ninth Edition, v. 2.djvu/246

Rh 228 AQUEDUCT Work at the Lochs 36,000 Aqueduct, 25J miles long, 468,000 Mugdock Reservoir 56,000 Main Pipes, 36 inches diameter, 123,000 Distribution in the city 78,000 Total for works, 761,000 Land and Compensation 70,000 Parliamentary expenseSjEnginearing, ) Q7 rnn ami Sundries, b7 00 157,000 Total, 918,000 Vienna Waterworks. A still more recent work, consisting mainly of aqueduct construction, is tho enterprise for supplying the city of Vienna with water. The water is obtained from the springs of Kaiserbrunn and Stixenstein, both situated at the foot of the Styrian Alps, which separate Austria from Styria. The Kaiserbrunn spring is situated 1146 English feet above the Danube at Vienna, and the Stixenstein spring 996 feet. The water is conducted by aqueduct to a receiving reservoir at Rosenhugel, 277 feet above the Danube, and distant 2 miles from Vienna. The length of the aqueduct from Kaiserbrunn to the receiving reservoir on the Rosenhugel, is 56| English miles. A branch of 3 9 English miles conducts the Stixenstein spring to this aqueduct. The gradients of the aqueduct vary much in tho upper or early parts ; but towards the end they become more regular. The gradients have been thus varied for the purpose of keeping the canal as much as possible along the level of the ground, so as to avoid high embankments. In order to keep the water cool in summer, and to secure it from freezing in winter, the water is always 6 feet below the surface; and in places where embankments were un avoidable, the aqueduct has been covered to tho same extent. The size of the aqueduct varies from 4 feet 6 inches in height, by 2 feet 6 inches in width, to 6 feet 6 inches in height, by 4 feet in width. In order to facilitate the discharge, and to reduce friction, the inside of the aqueduct has been plastered with a coating 2 inches thick of Portland cement and sand, in the proportion of one of cement to two of sand. This coating was laid on in three layers, the last being a very thin layer of pure cement, which, when hardened, was rubbed with iron plates till it became perfectly smooth and polished. The work was commenced in the winter of 1869-70, and com pleted in the month of September 1873. The aqueduct is constructed for the purpose of supplying about 3,200,000 cubic feet per day, or 20,000,000 gallons. There are Fid. 20. Baden Bridge, Vienna Waterworks (7 out of 43 arches). several important aqueduct bridges along the line of works. Of these the principal is the aqueduct of Baden, which consists of forty-three large arches, with spans varying from 5 klafters to 8| klafters, and the greatest height 15 klafters 5 feet 5 inches, or 9 6 6 English feet, from the foundation of the pier to the top of the aqueduct. The arches are of brickwork, as well as the vaulting of the canal. The piers, together with the backing of arches and the sides of the canal, are faced with ashlar, and filled up ^vith rubble masonry. The canal is covered on tho top with earth, which is then covered with 9 inches of paving in rubble masonry The Modling Aqueduct is, although one of tho shortest, perhaps the finest on tho whole line of the works. It is fcituated in a very narrow gorge, with high rocks rising on the side. The canal or aqueduct passes through a tuned on one side, and after crossing the aqueduct enters imme- Fia. 21. Modling Bridge, Vienna Waterworks. diately into another tunnel on the other. This aqueduct bridge consists of spans of 9 klafters, or 55 98 English feet, in width, and is built entirely of bricks, with tho exception that the piers are pointed with ashlar. The abutments, the foundations of which are excavated in the. rock, are built of rubble masonry, faced with ashlar. The? other chief aqueducts are the one at Liesing with forty- six arches, very similar to that of Baden, and that of Mauer with thirteen arches, built of bricks, and making a fine curve across the valley. The receiving reservoir on the llosenhugel, where the aque duct ends, is divided into two parts, capable together of holding 80,000 cubic feet English. From this reservoir the water is taken to two other distributing reservoirs, from which the city is supplied. The cost of the work, together with the network of pipes in Vienna, has been about 25,000,000 florins or 2,000,000 sterling. The chief engineer of the work was Herr Carl Junker of Vienna, and 1 the contractor Mr Antonio Gabrielli of London. The works were completed and opened in the autumn of 1873. Water Supply of Paris. The question of improving the water supply of this ci y was the subject of minute and careful investigations, extending over a period of four or five years, (from 1854 ta 1859.) Many projects were submitted to the Prefecture of the Seine, but the one finally adopted was that studied by Mr Belgrand and the engineers of the municipality of Paris. The scheme consisted in appropriating the waters of the Sonne and the Soude, together with the Soudon and the Dhuis, all being tributaries of the Marne, and flowing through chalk districts. The population of Paris, for the supply of which the scheme was laid out, was taken at 2,000,000, and the waters from the sources selected were intended for the domestic supply only the existing supplies to Paris, which have become gradually polluted and unfit for domestic use, being made available for all the other general wants of the population. The quantity of water which it was estimated would be required for the domestic purposes of such a population was taken at 100,000 cubic metres per diem, or about 22,000,000 gallons per day; and the works have been laid out for conveying this quantity. Gaugings of the various streams selected, showed that in 1855, when the flow was at the lowest, the produce of the Sonne and the Soude was 1081 litres per second, the Soudon 100, the Dhuis 315 ; making a total of 1496 litres per second, or about 28,000,000 gallons per day. At the time of lowest water in 1857, however, the Sonne and the SouJe together only yielded 880 litres per second, or 16,762,000 gallons per day, while in 1858, which was an exceptionally dry year (indeed the driest year on record in this locality), they yielded together only 285 litres per second, or 5,417,280 gallons per clay ; while in both these years the Soudon and the Dhuis gave almost the same quantities as in the year 1855. In order to meet the contingency of such a dry season as 1858, Mr Belgrand s project contemplated sinking wells or adits in the chalk, and obtaining therefrom what be
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