Roman Aqueducts :: essays research papers

Ancient Rome had eleven major aqueducts, built between 312 B.C. (Aqua Appia) and 226 A.D. (Aqua Alexandria) the daylong (Anio Novus) was 59 miles long. It has been calculated that in imperial times, when the citys population was well over a million, the distribution system was able to provide over one three-dimensional meter of irrigate per day for each inhabitant more than we use nowadays. For most of their length the early aqueducts were simply channels bored through the rock, from the water intake in the hills almost to the distribution cistern in Rome. The depth of the channel below ground varied so as to maintain a constant, very shallow gradient (less than 1/200) throughout the length of the aqueduct vertical shafts were bored at intervals to provide ventilation and access. Only in the final stretches was the conduit raise on arches, to give a sufficient head for distribution of the water within the city. In order to keep the gradient constant, the aqueducts took a roundab out route, following the contours of the land and heading along spurs which led towards Rome. The most dramatic parts of a Roman aqueduct wereand still arethe bridges (also known as arcades) that carried the water over low spots in the terrain. Perhaps the best-known of these is the Pont du Gard, a part of the aqueduct that served the town in Nmes in Gaul (todays France). The bridge stands on three tiers of arches and has a length of 274 m (900 ft). Built without the use of mortar, it stands 49 m (160 ft) above the Borngre Ravine. Another famous Roman aqueduct is the one in Segovia, Spain it still carries water, although it did need restoration in the 15th century. s time went on, Roman engineers became more daring in the construction of high arches to support the conduits perilways valleys and plains and some of the later aqueducts were as much as 27 meters (about 100 feet) above ground level in places. Closed pipes were occasionally used to cross valleys by the "inverted syp hon" method the pressure forced the water down and up again on the other side, to a level slimly lower than before. But this system was costly, as it required lead pipes (lead had to be imported from Spain or Great Britain) and it was difficult to make joints strong enough to make the pressure so arches were far more common.