The Nam Ou (
Laotian: ນ້ຳອູ ,
literally: "rice bowl river") is one of the most important
river
A river is a natural stream of fresh water that flows on land or inside Subterranean river, caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of ...
s of Laos. It runs 448 km from
Phongsaly Province to
Luang Prabang Province. The river rises in Muang Ou Nua near the Lao-Chinese border, and traverses the northern Laos mountains and gorges until meeting the Mekong River in Ban Pak Ou.
Along with the
Mekong
The Mekong or Mekong River ( , ) is a transboundary river in East Asia and Southeast Asia. It is the world's twelfth-longest river and the third-longest in Asia with an estimated length of and a drainage area of , discharging of wat ...
, the Nam Ou is the only natural channel suitable for large-draft
boat transportation. The Nam Ou is one of the 12 principal tributaries of the Mekong River.
The river has a total area of nearly 26,000 km
2.
Near its confluence with the Mekong are the
Pak Ou Caves, famous for their
Buddha statues
Much Buddhist art uses depictions of the historical Buddha, Gautama Buddha, which are known as () in Sanskrit and Pali. These may be statues or other images such as paintings. The main figure in an image may be someone else who has obtained B ...
. The river is also surrounded by limestone karts, forests, and valleys. The river supports Lao rice cultivation. The Nam Ou placed in the top 80th percentile for river health according to the
Mekong River Commission's aquatic health index.
Ecology

The Nam Ou river provides a habitat for 84 species of fish, with 29 of these species inhabiting the Nam Ou exclusively.
The northern portion of the river flows through
Phou Den Din National Protected Area (NPA) which is home to Asian elephants, Indochinese tigers, white-cheeked gibbons and large antlered muntjac – all endangered species.
The river also provides a habitat to riverine birds, otters, and reptiles, with many categorized as endangered by the IUCN Red List.
Cultural importance
Different ethnic minorities' villages with generations of history are located on the river and rely on the river for survival. This includes collecting resources from the river and surrounding forests for income, food, and spiritual practices.
The river and surrounding villages have also become a tourist destination for hikers, tour groups, and kayakers.
The
Phonsaly province of Laos is home to three main ethnic groups: the
Khmu, who account for 22% of the population; the
Songsiri (18%); and the
Akha (27%). The Khmu are the largest ethnic group in
Oudomxay, at 59% of the population; the
Lue account for 10% of the population; and the
Hmong make up 14% of the provincial population. The Khmu are also the main ethnic group in
Luang Prabang
Luang Prabang (Lao language, Lao: wikt:ຫຼວງພະບາງ, ຫຼວງພະບາງ, pronounced ), historically known as Xieng Thong (ຊຽງທອງ) and alternatively spelled Luang Phabang or Louangphabang, is the capital of Lu ...
, with 47% of the population; the
Lao ethnic group makes up 29% of the population; and the Hmong account for 16% of the population.
All six of these ethnic groups have different geographical origins, spiritual and religious practices, and occupational preferences/expertise.
Development
The Nam Ou River is the site of the
Nam Ou river cascade project, a series of seven dams at different sites along the river. 89 villages surrounding the river are expected to be relocated by the project.
There are concerns that the project may have a negative impact on local animal and plant species.
Development on the Nam Ou river and other hydropower projects on other tributaries or directly on the Mekong River have affected the river and surrounding land. The Mekong River Commission has occupied a precarious position of asking for patience to assess the consequences of hydropower projects while also previously stating the abundance of hydropower projects in the region may negatively affect river ecosystems and river sustainability. Thousands of Laotian villagers have been relocated as a result of hydropower development projects. Villagers in areas affected by hydropower projects are relocated by the Laotian government. Resettlement sites often include modernized towns with nearby amenities like roads, bridges, temples, trading markets, health centers and schools. Some of these have been built by contractors and developers of hydropower projects. Some villagers have trouble readjusting to new locations because they lose access to fish, river-bank gardens, and edible river vegetation.
References
{{Reflist
Rivers of Laos
Tributaries of the Mekong River