How long is the aqueduct built by King Herod at Caesarea Maritima?
Answer: 6.5 miles
Caesarea Maritima, the great harbor city built by Herod the Great in honor of his Roman patron Caesar Augustus,a had one major drawback—the city had no reliable source of fresh water. To overcome this problem, Herod and his engineers built a monumental arched aqueduct that carried fresh water into the city along a shallow gradient from a spring located 6.5 miles away, near the foot of Mt. Carmel.
Herod’s spring-fed aqueduct supplied the city with sufficient water for more than a century. During the reign of the Roman emperor Hadrian (117–138 C.E.), however, the city’s water demands increased considerably, requiring the tapping of a second water source and the expansion of the original aqueduct. A 6-mile-long underground extension of the aqueduct brought waters from the Tanninim river east of Caesarea to the Carmel spring. With the increased water flow, the arched aqueduct was then widened to support a second channel that ran directly parallel to the original Herodian channel.b This two-phased construction, known as the high-level aqueduct, is what visitors to Caesarea see today.