Vasai and Thane creeks are estuarine distributaries of the Ulhas River. Some rivers form complex networks of distributaries, especially in their deltas. This delta provides an environment that allows the Tigris and Euphrates to meander, forming distributaries. The abandoned distributaries diminish in volume and form what are known as bayous. At its mouth is Ilha Tupinambaranas, an extensive marshy region formed by the Madeira's distributaries. In the Nile Delta, the river splits into a number of distributaries and lesser channels. At the delta it splits into three distributaries. It begins diverging northeast of Dongguan into many distributaries, including the Dongguan Shuidao. Five distributaries of the Sarasvati are mentioned. Near the mouth, it splits into the Yaik and Zolotoy distributaries and forms vast wetlands. The environment is interpreted as sand bars formed at the mouth of a delta's distributaries. It is a fertile low lying plain interspersed with Krishna river and its distributaries. The Atchafalaya River is one of the major distributaries in the Mississippi River System. The most significant distributaries of the delta are listed in the table. Four rivers including Mahanadi and its distributaries Kathajodi, Kuakhai, Birupa run through the city.