A qanat is a tunnel used in arid regions for irrigation. It was invented in Iran, then called Persia, about 2,500 years ago and is still used today. It taps into underground water and uses the slope of the land to bring that water to where it's needed without pumping.
A rack containing these letters can be maddening. Two "a's" and no "u" to go with the "q." But don't despair. Qanat clears most of your letters and rids you of "q," scoring you at least 14 points in the process.