Niger Inland Delta During the Wet Season, Mali
An expansive green area stands out in the midst of the arid tan Sahel (semi-arid tropical savanna and steppe ecoregion) in Mali. This large stretch of green is the Inland Niger Delta. The area of the delta, which is fed by floodwaters from the Niger River (top), the Bani River (bottom) and many smaller streams, changes greatly over the course of the year.
During the dry season, the delta may have a surface area of around only 3,900 square kilometers (1,500 square miles). However, during the rainy season, which starts in July and lasts four months, it can grow to about 20,000 square kilometers (7,700 square miles). This image was taken at the end of September, three months into the wet season.