Salween River much of its length, the Salween's course is nearly parallel to that of the much larger Mekong in the east. Although the commonly accepted name is Salween, the river is known by a handful of other names regionally: "Nu" in China, "Thanlwin" in southern Burma, and "Salawin" on the border of Thailand and Burma. Several major sub-continental drainage basins border on the Salween. The Mekong basin forms nearly the entire eastern boundary of the watershed, while the Irrawaddy River flows southwards on the west side of the basin. The smallest boundary is formed by the Yangtze to the extreme north.
Achelous River in the westernmost part of the Trikala regional unit. One of its first tributaries is the Aspropotamos, meaning the white river. The river flows generally southwards, and forms part of the boundary between the regional units of Arta and Trikala, which is also the boundary between Epirus and Thessaly. Further downstream, it forms the boundary of Arta and Karditsa, and further of Aetolia-Acarnania and Evrytania. The river runs into the Kremasta reservoir, which is also fed by the rivers Agrafiotis and Megdovas. On exiting the Kremasta reservoir, the river flows southwest into Aetolia-Acarnania, feeding the Kastraki reservoir, west of the