ROMAN AQUEUCTS-MARVELS OF ENGINEERING

Construction and Maintenance

When you hear the words "Roman aqueduct," do you think of lofty arches running to distant horizons?  In fact, arches formed less than 20 percent of those conduits, the larger portion of which lay underground.  This more economical design not only protected aqueducts against erosion but also minimized their impact on fields and neighborhoods.  For example, the Aqua Marcia, completed in 14o B.C.E., was about 57 miles (92 km) long, but comprised just 7 miles or so (11 km) of arches.

Before building an aqueduct, engineers assessed the quality of a potential water source by examining the clarity, rate of flow, and taste of the water.  They also took note of the physical condition of the locals who drank it.  Once a site was approved, surveyors  calculated  the right path and gradient for the conduit,a s well as its channel size and length. Slaves evidently provided manpower. Aqueducts could take years to complete, making them costly-especially if arches were needed.

Moreover, aqueducts had to be maintained and protected. To care for them, the city of Rome at one time employed about 700 people. Provisions for maintenance were also incorporated into the design.  For instance, underground sections of the aqueducts were made accessible by means of manholes and shafts.  When major repairs were  needed, engineers could temporarily divert the water away from a damaged section.

Next time: ROMAN AQUEDUCTS MARVELS OF ENGINEERING-Rome's  Urban Aqueducts

From the Awake!  magazine, 2014