The Discovery Of The Roman Empire - 1740 Words

Figure 9 - A junction chamber cum settling tank on the Anio Novus diverting water into the Aqua Marcia and Aqua Claudia Unfortunately the problem with the Piscinae was that they would only take care of large sediments like sand and grit. Sediments on the order of 1 µm have a settling speed ‘ω’ of infinity (Equation 1), for example - clay particles, which do not need flowing water to stay in colloidal suspension. So the water reaching Rome would still be turbid. (Frontius Legacy p36-37) Despite arches and bridges being the most popular way of visualizing a Roman aqueduct, they constituted less than 6% of the total length of the Roman aqueducts {frontinus legacy}. Most of the aqueducts length was in channels or pipes underground, which on†¦show more content†¦The floor and sides of the channels were plastered with water-proofing made of cement interspersed with miniscule fragments Roman pottery. This waterproofing was called opus signinum and was generally 0.05 to 0.1 m thick. The average size of the channels was only vaguely related to the average water delivery expected of that section. The primary sizing consideration for these channels was for maintenance, so a man could enter it. {Roman aquae water sup Hodge p93-95}. Figure 10 – Excavation of the aqueduct showing the inspection manhole, masonry walls and stone roof When the duct reached a canyon or a valley and following the contour of the land was impractical, viaducts or bridges were constructed to maintain the steady gradient (Figure 11). Figure 11 - Diagram of viaduct These bridges were built from locally available building materials, like limestone or tufa, and hence had a maximum height limit empirically determined by the Romans to be around 50 m {RAWS hodge p129}. Bridges were preferred over reverse siphons for valley crossing for a few reasons; the materials for the bridge were quarried locally, so there was no need to transport large quantities of heavy lead long distances from the mines to the build site, leading to a significant drop in building cost; construction with brick and cement required lower skilled labor, like slaves or semi-skilled laborers, than working with lead pipes which required skilled welders to join