Qanat Irrigation System

Timeline

1. 1171–1174Central Iranian Plateau · IranA qanat is dug as a gently downward-sloping underground channel from an aquifer at the foot of a mountain, with vertical shafts along its length for ventilation and desilting; the outlet (mazhar) channels water into distribution troughs, allocating shares to fields, reducing evaporation and surface contamination, and suiting cultivation at desert margins.
2. c. 1175–1178Oases of Khwarazm and eastern Iran · KhwarazmIn the 1170s, towns such as Mashhad and Nishapur relied on qanat irrigation to grow wheat, grapes, and orchards; water shares were adjudicated by customary law and local governors, and diggers (muqannī) and landowners entered into long-term maintenance contracts.
3. 1178–1180Transoxiana and Tarim oases of Central Asia · Central AsiaQanat technology spread along the Silk Road into the oases of Central Asia, supporting the agriculture and caravan provisioning of cities such as Bukhara and Samarkand; although regimes in Central Asia changed frequently in the late 12th century, qanats remained an irreplaceable hydraulic foundation of settled civilization in arid regions.