Ancient desert city of Petra practiced sustainable terrace farming for 1000 years

Petra was a rich city and an important strategic conquest for Rome. They practiced food forestry with terraces for a 1000 years. They used intelligent water harvesting methods to irrigate their crops and supply the town with drinking water. Many of their techniques used gravity feed, keyline style methods. Their long term success in a hyper arid environment shows how sustainable keyline design and foood forestry can be. Some of the terminology used in the article reminds me of Geoff Lawton, the man who greened the Jordan desert.

http://www.sciencedaily.com/releases/2013/01/130102140443.htm