In the Nazca region a complex series of underground aqueducts bring water from rivers and aquifers (underground watercourses) to storage tanks in the surrounding desert lands, providing water for drinking and irrigation as well as fresh fish. These aqueducts run underground to prevent water loss through evaporation.
Deep ditches were dug and lined with pebbles to form drystone channels to hold the water. Wooden posts, of acacia which is resistant to rotting, support a roof of stone slabs. After roofing, the trenches were backfilled with earth and rubble.
Every 300 ft (250 m) or so, a stone built circular inspection pit gives access to the aqueduct for maintenance. Still in regular use, the antiquity of these aqueducts is not entirely certain, but they predate the arrival of Europeans in South America and were probably constructed after major droughts in the 6th century AD.
It is probable that they were built under the guidance of the highland Huari people, skilled hydraulic engineers, who dominated this area around AD 600-800.
