Sediments in the Gulf of Martaban from the Salween and Sittang Rivers, Myanmar16.5N 97.6E
The Gulf of Martaban is an arm of the Andaman Sea in the southern part of Burma. The gulf is named after the port city of Mottama (formerly known as Martaban). The Salween and Sittang rivers empty into it, causing it to be full of the thick tan sediments visible here.
The Salween River (also spelled Salwine, Thanlwin or Salawin) rises in Tibet, and flows primarily southeast and then south through China and Myanmar, at one point forming the border between Burma and Thailand, before entering the Andaman Sea, over 2,800 kilometres (1,700 mi) from its source.
The river drains a long, narrow and incredibly mountainous watershed that borders on the Mekong, Irrawaddy (Ayeyarwady) and Chang Jiang River basins. Although the river is very long, its basin is small by comparison—only about 324,000 square kilometres (125,000 sq mi).
Near the mouth the river has an average annual discharge of 1,659 cubic metres per second (58,600 cu ft/s), although this varies widely. The river’s base flow is provided by Tibetan glaciers, although it swells dramatically by the time it reaches the lowlands near the coast, especially in monsoon season
The Sittang (also spelled Sittaung or Sittoung) is a river in south central Myanmar in Bago Division. The Pegu Range separates its basin from that of the Irrawaddy. The river originates at the edge of the Shan Plateau southeast of Mandalay, and flows southward to the Gulf of Martaban. Its length is 420 km and its mean annual discharge is around 50 cubic kilometers per year.
Although it flows through fairly flat country, the Sittaung has a notorious tidal bore at its mouth which has precluded any but very small craft navigating the river. The river is navigable for 40 km year round and for 90 km during three months of the year. Its basin does not have the same richness for agriculture as the Irrawaddy because there is no soil flowing from the Himalayas.