> This is a tragic turnaround for an arid country with a proud tradition of sophisticated management of its meager water resources. Iran is the origin and cultural and engineering heartland of ancient water-collecting systems known as qanats.
> Qanats are gently sloping tunnels dug into hillsides in riverless regions to tap underground water, allowing it to flow out into valleys using gravity alone. They have long sustained the country’s farmers, as well as being until recently the main source of water for cities such as Tehran, Yazd, and Isfahan. But today only one in seven fields are irrigated by the tunnels.
> Iran has an estimated 70,000 of these structures, most of which are more than 2,500 years old.
2500 years old is roughly the beginning of Persia, with the conquest by Cyrus. If the network is mostly older than that, Iran may have a tradition of using them, but it doesn't seem to have much of a tradition of building them.
> Qanats are gently sloping tunnels dug into hillsides in riverless regions to tap underground water, allowing it to flow out into valleys using gravity alone. They have long sustained the country’s farmers, as well as being until recently the main source of water for cities such as Tehran, Yazd, and Isfahan. But today only one in seven fields are irrigated by the tunnels.
> Iran has an estimated 70,000 of these structures, most of which are more than 2,500 years old.
2500 years old is roughly the beginning of Persia, with the conquest by Cyrus. If the network is mostly older than that, Iran may have a tradition of using them, but it doesn't seem to have much of a tradition of building them.