The Sadd al-Bint (literally meaning the "dam of the girl" or the "dam of the daughter") is one of the largest ancient dams in the Saudi Kingdom. Although, it is unclear when the Sadd al-Bint was originally built, various dates and periods have been sugested for the origin of the. A local legend says that it was built during the reign of the Queen of Sheeba (most probably Sabaeans). It is likely this tradition refers to the early settlement of Sabaeans in the region around the mid third century CE, after the destruction of the Ma'rib Dam in ancient Saba. Since these people already had knowledge of water management systems like canals, dams and water conduits, it is likely that this dam was first built around the mid-third century CE by the Sabaeans who settled the Tayma, Khaybar and Yathrib regions.

This dam, massive in structure, may have acted as only part of a larger system of dams, canals and conduits since there's no evidence of ancient or modern vegetation and cultivation in its immediate vicinity. There are a number of other smaller dams and water channels that may have brought the water to the date-producing area of Khaybar.

circa 100 CE

The dam structure was around thirty meters in height, and spanned approx two hundred meters across the deep and steep valley. Since part of the ancient dam has collapsed the remaining part standing is approx. 135 meters long. Constructed on a dried out river bed, almost one third of it has been breached providing a unique insight in to its construction techniques. The collapsed part on the the north-eastern side allows to study the construction and evolution of the structure.

The "Khaybar Dam" is constructed out of black basalt rocks, which are abundant in the region. The upstream facade of the dam is plastered with yellow mortar to make it water-tight, the downstream facade is bare stone, it may have been plastered originally, but this has not survived today. On the downstream side of the dam, a double flight of steps (for unknown funtion or use) leads down into space on the edge of the dam.

The Khaybar Dam or the Sadd al-Qusaybah is situated on a minor curve in the valley, unlike many other dams that rud dead straight.

circa 100 CE

There is evidence, now lost, of sluice gates and other water controlling devices. The water from the dams at Khaybar was transported to the Khaybar plantation area using smaller water channels and conduits used to irrigate large plots of date palms. These dates became famous throughout the Arabian Peninsula. In time a large village was established. It was mostly inhabited by Jewish people. During the Muslim expansion under the Prophet Mohammed, Khaybar became an important center, after the Battel of Khaybar.