Energy through the ages: Water wheels

Water Wheel Energy

What did the Romans ever do for us? We all know the answer to that: plenty. One of their great skills was the efficiency with which they harnessed the power of water.

The Romans used water for agriculture and even hydraulic mining, to expose metal-bearing ore and power water wheel-driven hammers to crush it for processing. Water wheels were also commonly used for milling flour. Using a horizontal design, the wheel’s vanes, protruding from a wooden rotor and turned by a jet of water, then turned a mill wheel via a simple gear system.

Marvels of construction

The Romans are still known for their brilliantly engineered aqueduct systems. Conduits were built to move water long distances.  These were made of brick, stone and pozzuolana – a kind of volcanic concrete. Much of the water was carried underground but, where needed, bridges spanned the gaps across valleys and lowlands.

Rome’s first aqueduct, the Aqua Appia, built in 312 BC, supplied a water fountain at the city’s cattle market. Its source was a spring 10 miles from the city, which dropped a mere 30 feet over its length and supplied roughly 16 million gallons of water per day. The longest Roman aqueduct system was the Valens, which supplied Constantinople via 90 miles of tunnels, bridges and canals. At the peak of the Roman Empire almost 200 cities were supplied by aqueduct systems.

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