Sahara irrigation
| The Cufra Oasis in the Sahara Desert in southeastern Libya is easy to identify from space. In the vast desert expanse of yellow sand seas surrounding it, the dark feature stands out. Close inspection of this oasis reveals that it is made up of a number of of individual circular plots, each of which is a crop-bearing field irrigated by a center-pivot irrigation system. In this desert environment, the water supplying each field is likely pumped from a deep aquifer that contains ancient, nonreplaceable water. The differences in the colors of the fields are due to different amounts of growth and various types of crops. This image was taken on shuttle flight STS-26. |
Credit: Courtesy Kam Lulla, JSC. For more images of this type, see the "Human Imprints from Space" slide set (Gwynn, Wilkinson, and Lulla; Lunar and Planetary Institute #989)
For more info: http://images.jsc.nasa.gov/iams/images/earth/STS026/html/10001402.htm