Differences in the amount of sand cover explain the starkly contrasting colors of the Egyptian lake’s west and east banks.
An astronaut aboard the International Space Station captured this photograph of a short 30-kilometer-long (20-mile-long) segment of Lake Nasser—one of the world’s largest artificial lakes. The almost 500-kilometer-long (300-mile-long) reservoir formed after the Aswan High Dam was built across the Nile River in Aswan, Egypt. The northern two-thirds of the lake in Egypt is named after the country’s former president, Gamal Abdel Nasser, who is largely responsible for initiating the dam’s construction. The Sudanese portion is also known as Lake Nubia.
One notable feature in this image is the landscape dichotomy on either side of the lake. The geology in this area is characterized by medium to coarse-grained sandstone. The color difference between the west and east banks is caused by tan sand from sources to the west covering the underlying rock on that bank. In contrast, the eastern bank is characterized by exposed rock surfaces with little to no sand coverage. This is because wind transport is insufficient to transfer sand across the Nile Valley.
Astronaut photograph ISS069-E-442 was acquired on April 1, 2023, with a Nikon D5 digital camera using a focal length of 50 millimeters. It is provided by the ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit, Johnson Space Center. The image was taken by a member of the Expedition 69 crew. The image has been cropped and enhanced to improve contrast, and lens artifacts have been removed. The International Space Station Program supports the laboratory as part of the ISS National Lab to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public, and to make those images freely available on the Internet. Caption by Minna Adel Rubio, GeoControl Systems, JETS Contract at NASA-JSC.