There is a new word appearing in war stories from Afghanistan. The tribal authorities in the region of Tora Bora are worried that bombing bin Laden's hideout there will damage the "karez" which are small tunnels that start from the low valley areas and penetrate deep into the hills above to find water to irrigate the valley agriculture. Afghanistan has had a three year drought, and any injury to these irrigation structures would be very harmful.
These irrigation structures have been built in many places in the Middle East. There was an article about them in Scientific American quite a few years ago, but I can't remember the name for the structures used in the article. Do any of you remember it?