Saudi Arabia - Water Management in Saudi Arabia: The Ancient Dams

01 Sadd Al-Bint (also called Sadd Qusaybah) 25°29’6.04”N 39°21’46.38”E 02 Sadd Al-Hasid – Ancient Dam; Restored Dam 25°32’41.74”N 39°23’10.67”E 03 Sadd Al-Khanaq (also called Mu’awiyah) – Dam 1; Dam 2 24°26’34.28”N 39°55’7.33”E 04 Sadd Samallaqi 21°7’45.60”N 40°30’44.32”E 05 Sadd Al-‘Aqrab 21°26’0.00”N 40°35’0.00”E Water management represents the most critical and imperative condition for the development and prosperity of human societies. In Arabia, after several moisture episodes throughout the Early/Middle Holocene period, a Rapid Climate Change (RCC), activated around the 4th millennium BCE, has resulted in a severe decrease of annual precipitations, and an overall aggravated aridity that challenged agricultural development in most of the territory. This situation triggered human innovations and adaptive behaviours to counter water scarcity. The development of technologies such as wells, qanat, birkat (cisterns) and water diversion systems, permitted humans to live in the Peninsula, despite its extreme conditions, through the emergence of oases based on water catchment and control where sustainable agriculture could be practiced. While these irrigation techniques were used since the 3rd millennium BCE, large-scale dams in the region were developed much later, in the first centuries CE. Dams are “barriers built across a river in order to stop and retain the water from flowing, making large surface reservoirs.” They require a distinct type of technology, in terms of scale and ambition. In Arabia, they notably aimed to capture the rainwater made available during torrential rainfall or wadi flooding, playing a double role: to avoid the destructive impacts of floods on human settlements; and collect and use scarce and precious rainwater. To achieve those key objectives, dams required advanced hydro-engineering skills. They mobilised a precise knowledge of local topography, a deep understanding of the properties of construction materials, architectural/engineering knowledge to ensure their resistance, and familiarity with hydrology and water distribution systems to bring water to agricultural fields and wells.