During the flood season, the delta can grow to 20,000 square kilometers (7,700 square miles). During the dry season, it can shrink to 3,900 square kilometers (1,500 square miles). The flatness of the delta region—it drops only 8 meters (26 feet) over its entire length—leads to this large spread of water.
In the images, dark blue to black areas represent open water. The water expands and then noticeably begins shrinking in December. Any bright green, which is actively growing vegetation, also begins to diminish by late December. Dark blotches in the June image are bare ground. And this is roughly what it will look like again the following June.
These 2014 images show a flood level that was close to average.