Roman aqueducts show extreme hydraulic precision in new study

A geomatic study conducted by researchers from Sapienza University has provided new insights into the precision of Roman hydraulic engineering. Using high-precision tools such as dual-frequency GNSS and total stations, the team surveyed preserved sections of the Aqua Claudia and Anio Novus aqueducts south of Rome.

The findings reveal remarkably shallow gradients used to transport water. The Aqua Claudia was measured with a descent of 1.63 per mil (1.63 meters per kilometer), while the Anio Novus showed a descent of 1.31 per mil. These measurements highlight the technical ability of Roman engineers to maintain consistent water flow over vast distances using trenches, tunnels, and stone arches only when necessary to cross valleys.

The research clarifies historical discrepancies regarding the administrative lengths of these structures. While some reports suggest much longer continuous stretches with specific slopes, the survey indicates that the actual physical gradients varied according to the topography, functioning as a ‘gentle saw’ rather than a perfectly straight line.