Aqueducts moved water through gravity alone, along a slight downward gradient within conduits of stone, brick or concrete. Most were buried beneath the ground, and followed its contours; obstructing peaks were circumvented or less often, tunneled through. Where valleys or lowlands intervened, the conduit was carried on bridgework, or its contents fed into high-pressure …show more content…
The road allowed rapid troop movements; and by design or fortunate coincidence, most of the Aqua Appia ran within a buried conduit, relatively secure from attack. It was fed by a spring 16.4 km from Rome and dropped 10 meters over its length to discharge approximately 75,500 cubic meters of water per diem into a fountain at Rome's cattle market, the Forum Boarium, one of the city's lowest lying public spaces. A second aqueduct, the Old Anio, was commissioned some forty years later, funded by booty seized from Pyrrhus of Epirus. Its flow was more than twice that of the Aqua Appia, and it entered the city on raised arches, supplying water to higher elevations of the city.
By 145 BC, the city had again outgrown its combined supplies; an official commission found the aqueduct conduits decayed, and depleted by leakage and illegal tapping. The praetor Quintus Marcius Rex restored them, and introduced a third, "more wholesome" supply, the Aqua Marcia, Rome's longest aqueduct and high enough to supply the Capitoline Hill. The works cost 180,000,000 sesterces, and took two years to