Bidaa Bint Saud () is an archaeological site in Al-Ain Region, Abu Dhabi, United Arab Emirates, notable for its Hafit Period tombs, Iron Age irrigation systems and rare remains of an Iron Age building thought to have been a distribution centre for water from two aflaj (systems of underground and surface waterways). It is a listed UN World Heritage Site. Finds from the site are displayed at Al Ain National Museum. The dating of pottery from the aflaj (singular falaj) waterways found at the site demonstrates a south-eastern Arabian origin for this distinctive system of irrigation, previously thought by many scholars to have been Persian in origin. The dating of aflaj in Bidaa bint Saud, Al Ain and Buraimi, both of which are in the historical region of Tawam, has been placed several centuries prior to the Achaemenid Empire, which had previously been credited with the innovation. The site, located some north of Al Ain, is thought to have been a stopping place on a long-established caravan route from settlements at Al Ain to the Northern Emirates. The rocky outcrop of Garn bin Saud looms some above the site and is dotted with burial remains. Bronze Age tombs A number of distinctive Hafit Period (3200 to 2600 BCE) tombs litter the eastern face of Garn bint Saud, similar to those found at sites such as Jebel Hafit, Jebel Buhais and Buraimi. These have collapsed and would originally have had domed roofs. It is likely the location of the Hafit remains, the Hafit people being nomadic and pastoral, is because of a source of groundwater, a pattern supported by other Hafit era inland finds, including those at Jebel Hafit and Jebel Buhais. Iron Age waterways A second set of collective graves found at the site dated from the Iron Age and were also built of uncut or rough-cut stone and formed into a variety of shapes. These were divided into several chambers, each of which contained the remains of several people. Despite having been plundered in the past, excavations from these Iron Age tombs yielded a number of artefacts, including pottery and stone vessels, dagger blades, bronze arrowheads, and beads. It is thought Bidaa Bint Saud became an important site during the Iron Age, both as a caravan stop and as a settled community of farmers that used the falaj irrigation system. Two of these irrigation passages have been partly excavated