Aqua Marcia

Content sourced from Wikipedia, licensed under CC BY-SA 3.0.

Aqua Marcia (Acqua Marcia) is a 91-kilometer Roman aqueduct—the longest that fed Rome. It was built between 144 and 140 BC and is one of Rome’s four great aqueducts, along with Aqua Anio Vetus, Aqua Anio Novus, and Aqua Claudia. Its water came from springs in the Anio valley near Arsoli and Marano Equo. For most of its length the pipe ran underground, but the last 11 kilometers came to Rome on large arches, making Aqua Marcia the first aqueduct to enter the city on arches.

The project was supervised by Quintus Marcius Rex and largely funded by spoils from Rome’s conquests after 146 BC. Building it to reach the Capitoline Hill was controversial because some feared violating a Sibylline warning about bringing water there, but construction continued and was completed around 140 BC. Agrippa repaired it in 33 BC, and Augustus rebuilt much of it between 11 and 4 BC, adding a new source called Augusta to increase supply.

Over time much of the water was diverted by private users, leaving only a trickle by the time of Nero. Later emperors restored and expanded the system. Around AD 97, Frontinus measured a strong flow from the source, making Aqua Marcia one of Rome’s largest water sources; modern estimates vary, but the aqueduct supplied tens of millions of liters of water each day.

The main network fed Rome, with a branch serving the Caelian and Aventine hills. Along its route are several famous bridges, some still visible today, such as Ponte Lupo and Ponte Caipoli. There is also a long maintenance tunnel and numerous inspection shafts.

In later centuries, Trajan, Hadrian, and the emperors Septimius Severus and Caracalla restored or expanded parts of Aqua Marcia; Caracalla added another source to supply baths. Some later restorations may have occurred under Diocletian as well. The aqueduct’s legacy lies in its especially cold, pure water and in its impressive engineering, which helped shape Rome’s water system for generations.