Lake Nasser in the upper right of this scene is a sprawling man-made reservoir formed by the damming of the Nile River. With a potential capacity of 168 million cubic meters, this is one of the largest reservoirs in the world. The Aswan High Dam that holds back this reservoir was completed in 1970. The damming of the Nile River was undertaken by Egypt to provide the country with a dependable supply of water and hydroelectric power and to control flooding. Although these goals have been achieved, a few problems have developed. First, the dam traps nutrient-rich sediment that would otherwise blanket downstream farmland. This is a common problem with dammed rivers and eventually results in reduced soil fertility. Second, the reservoir experiences a high rate of water loss due to evaporation in this arid region.
The headwaters of the Nile are located thousands of kilometers south of Egypt in the Sahel, a region that experiences significant rainfall. As can be seen in this photograph, the land surrounding Lake Nasser and the Nile River in Egypt is essentially desert (different rock outcrops and desert surfaces account for the color patterns). As such, the overwhelming majority (over 99%) of the population of Egypt is forced to live along the Nile River or its delta. Egypt's heavy dependence on the water of the Nile has forced it to take a very serious stance regarding its management.
October–November 1992, image STS-52-151-181.