When was the first aqueduct built?
Roman aqueduct
At Barbegal in Roman Gaul, a reservoir fed an aqueduct that drove a cascaded series of 15 or 16 overshot water mills, grinding flour for the Arles region. Similar arrangements, though on a lesser scale, have been found in Caesarea, Venafrum and Roman-era Athens. Rome's Aqua Traiana drove a flour-mill at the Janiculum, west of the Tiber. A mill in the basement of the Baths of Caracalla was driven by aqueduct overspill; this was but one of many city mills driven by aqueduct water, with or without official permission. A law of the 5th century forbade the illicit use of aqueduct water for milling.[47]