|Freshwater Resources in Arid Lands (UNU, 1997, 94 pages)|
|1: Fresh water - A scarce resource in arid lands|
Dew Irrigation and Flood Irrigation
Using condensed dew water from the surface of piled stones arranged in a circle, arid-land inhabitants were able to cultivate vegetables inside the circle. Constructing small dykes dams in the flood plain, they could catch the flood water and send it to the fields. Those traditional methods can still be seen in Mesopotamia or Arabia.
Since 1956, I have been working mainly on this topic. The research field has already covered, inter alia, Xinjiang, Turkmenistan, Iraq, Syria, Jordan, Israel, the Arabian Peninsula, Egypt, Libya, Tunisia, Algeria, Morocco, Majorca, Andalusia, Mexico, Peru, and Chile.
Qanat is genuine civil engineering to transport groundwater via underground channels to the surface in the villages. The diffusion of qanat (also known as karez or foggara) is found mainly in the arid and semi-arid regions of Eurasia and, to a limited extent, in South America, but the origin of the technique is still obscure. However, even now, in small parts of the Sahara, Iran, Afghanistan, Turfan, and Oman, the system is still useful and operating to get fresh water using only gravity. Nevertheless, because of difficult construction works and the need for much manpower for maintenance, the qanat system is now almost extinct. However, the technique is very sustainable and gentle to the environment. The modernization of digging technology may sustain the qanat system in suitable areas.