"The main rivers of Myanmar have been briefly described. The Ayeyarwady river system has been divided up into the Upper, Middle and Lower Ayeyarwady, leading into the Delta. The Chindwin is a large tributary of the Ayeyarwady and has been described separately, so that there are five main basins of the Ayeyarwady river system. The Thanlwin is described from the point of entry into Myanmar from China through to its estuary at Mawlamyine. It has a very different character to the Ayeyarwady system, being principally a narrow rock cut channel for most of its length. The Sittaung is a much smaller river system running from north to south between the two major river basins, before discharging into the Gulf of Mottama. The Myit Ma Hka and Bago river basins are two very small basins near Yangon between the Sittaung and Ayeyarwady. There are two coastal river basins, the Rakhine coastal basin consisting of a number of smaller rivers, including the Kaladan, Lemyo and Mayu rivers, with water arising in the Rakhine Yoma and flowing into the Bay of Bengal, and in the Tanintharyi coastal basin which contains the Tanintharyi and Lenya rivers, flowing into the Andaman Sea. In the absence of strong data bases to describe the ecological value of the different river systems in Myanmar, the approach has been taken of attributing importance of different aspects to a standard dataset classifying all of the 36 different types of river reach found in Myanmar rivers. River reach rarity according to the total lengths of river reach is taken as an important ecological attribute, as are the areas around confluences and rivers flowing through limestone karst geology. Reaches lying within known areas where endemic fish species are found, including areas such as the Rakhine and Bago Yomas, headwaters of the Ayeyarwady and Chindwin, Indawgyi and Inle Lake areas and in the Tanintharyi coastal rivers. The important river and wetland areas have been noted including those identified from the Key Biodiversity Areas, Ramsar and potential Natural World Heritage Sites and wetlands surveyed during the 2004 Wetland Inventory of Myanmar. The IBAT and IUCN Redlist databases have been used to identify areas important for threatened species of turtles, molluscs, aquatic insects, crustacea and aquatic plants. Similarly, the likely presence of threatened fish species in different sub-basins has been used to identify importance of river reaches using the IBAT and Redlist databases. The importance of migratory fish such as Hilsa, eels, and Tor species are recognized and the mainstem reaches of each river receive recognition of the importance of ecosystem connectivity. Areas where aquatic mammals are found such as the Irrawady Dolphin and otter species have been described. The process provides an identification of the ecological sensitivity of the different river reaches in all the rivers in Myanmar, except for the Rakhine Coastal Basin, where the primary river reach database does not extend. These rivers are described qualitatively. The ecosystem services provided by Myanmar’s rivers have been described qualitatively. In particular, detail has been provided on the fisheries provisioning services, which is one of the most important ecosystem services provided by the rivers. Information is provided on the freshwater and inshore fisheries and aquaculture and their contributions to livelihoods and nutrition of people living along the rivers. The distribution of the leasehold areas for commercial fishing by township is provided. Note is taken of the increasing recognition of the role of women in the fisheries sector. An analysis of the distribution of fish species which have different utilization is provided – commercial uses, subsistence and their potential as ornamental species. Other provisioning services include timber and textile materials from riparian vegetation, and the use of molluscs, crustacea and turtle species for food. Regulating services include hydrological services such as the seasonal flows patterns, groundwater recharge, flood alleviation in the floodplains, sediment transport and sand and gravel extraction, and maintenance of water quality. Supporting services include nutrient transport from the upper reaches to the floodplains and delta, biodiversity support providing ecosystems and habitats for the different lifecycles of fish and other aquatic organisms, and the river connectivity, which is so important for migratory species. Cultural services include the cultural importance of the rivers of Myanmar to its peoples, and of specific features such as confluences e.g. at Myitsone, deep pools, rapids and water falls. Cultural services include navigation and tourism, especially on the Ayeyarwady..."