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The Mekong or Mekong River ( , ) is a
transboundary river A transboundary river is a river that crosses at least one political border, either a border within a state or an international boundary. Bangladesh has the highest number of these rivers, with at least 58 major rivers that enter the country from ...
in
East Asia East Asia is a geocultural region of Asia. It includes China, Japan, Mongolia, North Korea, South Korea, and Taiwan, plus two special administrative regions of China, Hong Kong and Macau. The economies of Economy of China, China, Economy of Ja ...
and
Southeast Asia Southeast Asia is the geographical United Nations geoscheme for Asia#South-eastern Asia, southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of the Mainland Au ...
. It is the world's twelfth-longest river and the third-longest in Asia with an estimated length of and a
drainage area A drainage basin is an area of land in which all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, th ...
of , discharging of water annually. From its
headwater The headwater of a river or stream is the geographical point of its beginning, specifically where surface runoff water begins to accumulate into a flowing channel of water. A river or stream into which one or many tributary rivers or streams flo ...
s in the
Tibetan Plateau The Tibetan Plateau, also known as the Qinghai–Tibet Plateau or Qingzang Plateau, is a vast elevated plateau located at the intersection of Central Asia, Central, South Asia, South, and East Asia. Geographically, it is located to the north of H ...
, the river runs through
Southwest China Southwestern China () is a region in the People's Republic of China. It consists of five provincial administrative regions, namely Chongqing, Sichuan, Guizhou, Yunnan, and Xizang. Geography Southwestern China is a rugged and mountainous region, ...
(where it is officially called the Lancang River),
Myanmar Myanmar, officially the Republic of the Union of Myanmar; and also referred to as Burma (the official English name until 1989), is a country in northwest Southeast Asia. It is the largest country by area in Mainland Southeast Asia and has ...
,
Laos Laos, officially the Lao People's Democratic Republic (LPDR), is the only landlocked country in Southeast Asia. It is bordered by Myanmar and China to the northwest, Vietnam to the east, Cambodia to the southeast, and Thailand to the west and ...
,
Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...
,
Cambodia Cambodia, officially the Kingdom of Cambodia, is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. It is bordered by Thailand to the northwest, Laos to the north, and Vietnam to the east, and has a coastline ...
, and
southern Vietnam Southern Vietnam () is one of the three geographical regions of Vietnam, the other two being Northern and Central Vietnam. It includes 2 administrative subregions, which in turn are divided into 19 ''First Tier units'', of which 17 are provi ...
. The extreme seasonal variations in flow and the presence of
rapid Rapid(s) or RAPID may refer to: Hydrological features * Rapids, sections of a river with turbulent water flow * Rapid Creek (Iowa River tributary), Iowa, United States * Rapid Creek (South Dakota), United States, namesake of Rapid City Sport ...
s and
waterfall A waterfall is any point in a river or stream where water flows over a vertical drop or a series of steep drops. Waterfalls also occur where meltwater drops over the edge of a tabular iceberg or ice shelf. Waterfalls can be formed in seve ...
s in the Mekong make
navigation Navigation is a field of study that focuses on the process of monitoring and controlling the motion, movement of a craft or vehicle from one place to another.Bowditch, 2003:799. The field of navigation includes four general categories: land navig ...
difficult, though the river remains a major trade route between Tibet and Southeast Asia. The construction of
hydroelectric dam Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energ ...
s along the Mekong in the 2000s through the 2020s has caused serious problems for the river's
ecosystem An ecosystem (or ecological system) is a system formed by Organism, organisms in interaction with their Biophysical environment, environment. The Biotic material, biotic and abiotic components are linked together through nutrient cycles and en ...
, including the exacerbation of
drought A drought is a period of drier-than-normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D.  Jiang, A.  Khan, W.  Pokam Mba, D.  Rosenfeld, J. Tierney, ...
.


Names

The Mekong was originally called ''Mae Nam Khong'' from a contracted form of Kra-Dai shortened to ''Mae Khong''. In Thai and Lao, ''Mae Nam'' ("Mother of Water ) is used for large rivers and ''Khong'' is the proper name referred to as "River Khong". However, ''Khong'' is an archaic word meaning "river", loaned from
Austroasiatic languages The Austroasiatic languages ( ) are a large language family spoken throughout Mainland Southeast Asia, South Asia and East Asia. These languages are natively spoken by the majority of the population in Vietnam and Cambodia, and by minority popu ...
, such as Vietnamese ''sông'' (from *''krong'') and Mon ''kruŋ'' "river", which led to Chinese whose
Old Chinese Old Chinese, also called Archaic Chinese in older works, is the oldest attested stage of Chinese language, Chinese, and the ancestor of all modern varieties of Chinese. The earliest examples of Chinese are divinatory inscriptions on oracle bones ...
pronunciation has been reconstructed as and which long served as the proper name of the
Yangtze The Yangtze or Yangzi ( or ) is the longest river in Eurasia and the third-longest in the world. It rises at Jari Hill in the Tanggula Mountains of the Tibetan Plateau and flows including Dam Qu River the longest source of the Yangtze, i ...
before becoming a generic word for major rivers. To the early European traders, the Mekong River was also known as ''Mekon River'', ''May-Kiang River'' and ''Cambodia River''. Historian William Dalrymple suggests that Mekong comes from "Ma Ganga" which means Mother Ganges. Hindus think of the river Ganges as mother. The local names for the river include: # From Thai: #*, , or just . #*, , or just . #*, , or just . #*, , or just . #* Tai Lue: , . #* or . # Other: #* () or , ( ''Nine Dragons River'' ). #*Chinese: . #*, . #* ''Tônlé Thum'' (lit. "Big River" or "Great River") or ''Mékôngk'' , ''Tônlé Mékôngk'' . #* Khmuic: , '' means 'river' or 'water', here it means 'river', '' means 'canal'. So '' means 'canal river'. In the ancient time Khmuic people called it '' or '' which means 'giant canal river' or 'deep canal river' respectively.


Course

The Mekong rises as the Za Qu (; ) and soon becomes known as the Lancang River (, from the old name of Lao kingdom
Lan Xang Lan Xang () or Lancang was a Lao people, Lao kingdom that held the area of present-day Laos from 1353 to 1707. For three and a half centuries, Lan Xang was one of the largest kingdoms in Southeast Asia. The kingdom is the basis for Laos's nat ...
; the characters may also be literally understood as "turbulent green river"). It originates in the " three rivers source area" on the
Tibetan Plateau The Tibetan Plateau, also known as the Qinghai–Tibet Plateau or Qingzang Plateau, is a vast elevated plateau located at the intersection of Central Asia, Central, South Asia, South, and East Asia. Geographically, it is located to the north of H ...
in the
Sanjiangyuan National Nature Reserve The Sanjiangyuan ( zh, c=三江源, l=Source of Three Rivers), is an area of the Tibetan Plateau in Qinghai province, China which contains the headwaters of three great rivers of Asia: the Yellow, the Yangtze, and the Mekong. Parts of the area w ...
. The reserve protects the headwaters of, from north to south, the
Yellow Yellow is the color between green and orange on the spectrum of light. It is evoked by light with a dominant wavelength of roughly 575585 nm. It is a primary color in subtractive color systems, used in painting or color printing. In t ...
(Huang He), the
Yangtze The Yangtze or Yangzi ( or ) is the longest river in Eurasia and the third-longest in the world. It rises at Jari Hill in the Tanggula Mountains of the Tibetan Plateau and flows including Dam Qu River the longest source of the Yangtze, i ...
, and the Mekong Rivers. It flows through the
Tibetan Autonomous Region The Tibet Autonomous Region (TAR), often shortened to Tibet in English or Xizang in Hanyu Pinyin, is an autonomous region of the People's Republic of China. It was established in 1965 to replace the Tibet Area, a former administrative divisio ...
and then southeast into
Yunnan Yunnan; is an inland Provinces of China, province in Southwestern China. The province spans approximately and has a population of 47.2 million (as of 2020). The capital of the province is Kunming. The province borders the Chinese provinces ...
Province, and then the Three Parallel Rivers Area in the
Hengduan Mountains The Hengduan Mountains () are a group of mountain ranges in southwest China, southwest China that connect the southeast portions of the Tibetan Plateau with the Yunnan–Guizhou Plateau. The Hengduan Mountains are primarily large north-south ...
, along with the Yangtze to its east and the
Salween River The Salween is a Southeast Asian river, about long, flowing from the Tibetan Plateau south into the Andaman Sea. The Salween flows primarily within southwest China and eastern Myanmar, with a short section forming the border of Myanmar and Tha ...
(Nu Jiang in Chinese) to its west. Then the Mekong meets the China–Myanmar border and flows about along that border until it reaches the
tripoint A triple border, tripoint, trijunction, triple point, or tri-border area is a geography, geographical point at which the boundaries of three countries or Administrative division, subnational entities meet. There are 175 international tripoints ...
of China,
Myanmar Myanmar, officially the Republic of the Union of Myanmar; and also referred to as Burma (the official English name until 1989), is a country in northwest Southeast Asia. It is the largest country by area in Mainland Southeast Asia and has ...
and
Laos Laos, officially the Lao People's Democratic Republic (LPDR), is the only landlocked country in Southeast Asia. It is bordered by Myanmar and China to the northwest, Vietnam to the east, Cambodia to the southeast, and Thailand to the west and ...
. From there it flows southwest and forms the border of Myanmar and Laos for about until it arrives at the tripoint of Myanmar, Laos, and
Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...
. This is also the point of confluence between the
Ruak River The Ruak River (, , ; น้ำแม่ฮวก, ) is a right hand tributary of the Mekong. The mouth of the Ruak river is at the Thai-Burma border opposite Laos, a spot known as the " Golden Triangle", a popular tourist destination. Course Th ...
(which follows the Thai–Myanmar border) and the Mekong. The area of this tripoint is sometimes termed the Golden Triangle, although the term also refers to the much larger area of those three countries that was notorious as a drug producing region. From the Golden Triangle tripoint, the Mekong turns southeast to briefly form the border of Laos with Thailand. Khon Pi Long is a series of
rapid Rapid(s) or RAPID may refer to: Hydrological features * Rapids, sections of a river with turbulent water flow * Rapid Creek (Iowa River tributary), Iowa, United States * Rapid Creek (South Dakota), United States, namesake of Rapid City Sport ...
s along a section of the Mekong River dividing Chiang Rai and Bokeo Province in Laos. The name of the rapids means 'where the ghost lost its way'. It then turns east into the interior of Laos, flowing first east and then south for some before meeting the border with Thailand again. Once more, it defines the Laos-Thailand border for some as it flows first east, passing the capital of Laos,
Vientiane Vientiane (, ) is the capital city, capital and largest city of Laos. Situated on the banks of the Mekong, Mekong River at the Thailand, Thai border, it comprises the five urban districts of Vientiane Prefecture and had a population of 840,000 ...
, then turns south. A second time, the river leaves the border and flows east into Laos soon passing the city of
Pakse Pakse (or ''Pakxe''; French: ''Paksé''; Laotian: ປາກເຊ 'mouth of the river') is the capital and most populous city of the southern Laotian province of Champasak. Located at the confluence of the Xe Don and Mekong Rivers, the distri ...
. Thereafter, it turns and runs more or less directly south, crossing into
Cambodia Cambodia, officially the Kingdom of Cambodia, is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. It is bordered by Thailand to the northwest, Laos to the north, and Vietnam to the east, and has a coastline ...
. At
Phnom Penh Phnom Penh is the Capital city, capital and List of cities and towns in Cambodia, most populous city of Cambodia. It has been the national capital since 1865 and has grown to become the nation's primate city and its political, economic, industr ...
the river is joined on the right bank by the river and lake system the
Tonlé Sap Tonlé Sap (; , ; or commonly translated as 'Great Lake') is a lake in the northwest of Cambodia. Belonging to the Mekong, Mekong River system, Tonlé Sap is the largest freshwater lake in Southeast Asia and one of the most diverse and prod ...
. When the Mekong is low, the Tonle Sap is a
tributary A tributary, or an ''affluent'', is a stream or river that flows into a larger stream (''main stem'' or ''"parent"''), river, or a lake. A tributary does not flow directly into a sea or ocean. Tributaries, and the main stem river into which they ...
: water flows from the lake and river into the Mekong. When the Mekong floods, the flow reverses: the floodwaters of the Mekong flow up the Tonle Sap. Immediately after the Sap River joins the Mekong by Phnom Penh, the
Bassac River The Bassac River (; Tonlé Bassac) or Hậu River ( 瀧後 or 後江) is a distributary of the Tonlé Sap and Mekong River. The river starts in Phnom Penh, Cambodia, and flows southerly, crossing the border into Vietnam near Châu Đốc. Th ...
branches off the right (west) bank. The Bassac River is the first and main distributary of the Mekong. This is the beginning of the Mekong Delta. The two rivers, the Bassac to the west and the Mekong to the east, enter Vietnam shortly after this. In Vietnam, the Bassac is called the Hậu River (Sông Hậu or Hậu Giang); the main, eastern, branch of the Mekong is called the
Tiền River The Tiền River ( 瀧前 or 前江) is the name given to the section of the Mekong’s mainstream in Vietnam. At Phnom Penh Phnom Penh is the Capital city, capital and List of cities and towns in Cambodia, most populous city of Cambodia. ...
or Tiền Giang. In Vietnam, distributaries of the eastern (main, Mekong) branch include the Mỹ Tho River, the Ba Lai River, the
Hàm Luông River The Hàm Luông River () is a branch of Mekong River in the Mekong Delta region, Vietnam Vietnam, officially the Socialist Republic of Vietnam (SRV), is a country at the eastern edge of mainland Southeast Asia, with an area of about an ...
, and the Cổ Chiên River.


Drainage basin

The Mekong Basin is frequently divided into two parts: the "upper Mekong basin" comprising those parts of the basin in
Tibet Tibet (; ''Böd''; ), or Greater Tibet, is a region in the western part of East Asia, covering much of the Tibetan Plateau and spanning about . It is the homeland of the Tibetan people. Also resident on the plateau are other ethnic groups s ...
,
Yunnan Yunnan; is an inland Provinces of China, province in Southwestern China. The province spans approximately and has a population of 47.2 million (as of 2020). The capital of the province is Kunming. The province borders the Chinese provinces ...
and eastern
Myanmar Myanmar, officially the Republic of the Union of Myanmar; and also referred to as Burma (the official English name until 1989), is a country in northwest Southeast Asia. It is the largest country by area in Mainland Southeast Asia and has ...
, and the "lower Mekong basin" from
Yunnan Yunnan; is an inland Provinces of China, province in Southwestern China. The province spans approximately and has a population of 47.2 million (as of 2020). The capital of the province is Kunming. The province borders the Chinese provinces ...
downstream from China to the
South China Sea The South China Sea is a marginal sea of the Western Pacific Ocean. It is bounded in the north by South China, in the west by the Indochinese Peninsula, in the east by the islands of Taiwan island, Taiwan and northwestern Philippines (mainly Luz ...
. From the point where it rises to its mouth, the most precipitous drop in the Mekong occurs in the upper Mekong basin, a stretch of some . Here, it drops before it enters the lower basin where the borders of Thailand, Laos, China, and Myanmar come together in the Golden Triangle. Downstream from the Golden Triangle, the river flows for a further through Laos, Thailand, and
Cambodia Cambodia, officially the Kingdom of Cambodia, is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. It is bordered by Thailand to the northwest, Laos to the north, and Vietnam to the east, and has a coastline ...
before entering the
South China Sea The South China Sea is a marginal sea of the Western Pacific Ocean. It is bounded in the north by South China, in the west by the Indochinese Peninsula, in the east by the islands of Taiwan island, Taiwan and northwestern Philippines (mainly Luz ...
via a complex delta system in
Vietnam Vietnam, officially the Socialist Republic of Vietnam (SRV), is a country at the eastern edge of mainland Southeast Asia, with an area of about and a population of over 100 million, making it the world's List of countries and depende ...
.


Upper basin

The upper basin makes up 24% of the total area and contributes 15–20% of the water that flows into the Mekong River. The
catchment A drainage basin is an area of land in which all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, th ...
here is steep and narrow with
Soil erosion Soil erosion is the denudation or wearing away of the Topsoil, upper layer of soil. It is a form of soil degradation. This natural process is caused by the dynamic activity of erosive agents, that is, water, ice (glaciers), snow, Atmosphere of Ea ...
being a major problem and as a result of this, approximately 50% of the sediment in the river comes from the upper basin. In Yunnan Province in China, the river and its tributaries are confined by narrow, deep gorges. The tributary river systems in this part of the basin are small. Only 14 have catchment areas that exceed , yet the greatest amount of loss of
forest cover Forest cover is the amount of trees that covers a particular area of land. It may be measured as relative (in percent) or absolute (in square kilometres/ square miles). Nearly a third of the world's land surface is covered with forest, with clos ...
in the entire river system per square kilometer has occurred in this region due to heavy unchecked demand for natural resources. In the south of Yunnan, in Simao and
Xishuangbanna Xishuangbanna, sometimes shortened to Banna, is one of the eight autonomous prefectures of Yunnan Province. The autonomous prefecture for Dai people is in the extreme south of Yunnan province, China, bordering both Myanmar and Laos. Xishuangbanna ...
Prefectures, the river changes as the valley opens out, the floodplain becomes wider, and the river becomes wider and slower.


Lower basin

Major tributary systems develop in the lower basin. These systems can be separated into two groups: tributaries that contribute to the major wet season flows, and tributaries that drain low relief regions of lower rainfall. The first group are left bank tributaries that drain the high rainfall areas of Laos. The second group are those on the right bank, mainly the Mun and Chi Rivers, that drain a large part of northeast Thailand. Laos lies almost entirely within the lower Mekong basin. Its climate, landscape and land use are the major factors shaping the hydrology of the river. The mountainous landscape means that only 16% of the country is farmed under lowland terrace or upland
shifting cultivation Shifting cultivation is an agricultural system in which plots of land are cultivated temporarily, then abandoned while post-disturbance fallow vegetation is allowed to freely grow while the cultivator moves on to another plot. The period of cul ...
. With upland shifting agriculture (slash and burn), soils recover within 10 to 20 years but the vegetation does not. Shifting cultivation is common in the uplands of northern Laos and is reported to account for as much as 27% of the total land under rice cultivation. As elsewhere in the basin, forest cover has been steadily reduced during the last three decades by shifting agriculture and permanent agriculture. The cumulative impacts of these activities on the river regime have not been measured. However, the hydrological impacts of land cover changes induced by the
Vietnam War The Vietnam War (1 November 1955 – 30 April 1975) was an armed conflict in Vietnam, Laos, and Cambodia fought between North Vietnam (Democratic Republic of Vietnam) and South Vietnam (Republic of Vietnam) and their allies. North Vietnam w ...
were quantified in two sub-catchments of the lower Mekong River basin. Loss of forest cover in the Thai areas of the lower basin has been the highest of all the lower Mekong countries over the past 60 years. On the
Khorat Plateau The Khorat Plateau (; ) is a plateau in the northeastern Thai region of Isan. The plateau forms a natural region, named after the short form of Nakhon Ratchasima, a historical barrier controlling access to and from the area. Geography The avera ...
, which includes the Mun and
Chi __NOTOC__ Chi may refer to: __NOTOC__ Greek *Chi (letter) (Χ or χ), the twenty-second letter of the Greek alphabet Chinese * ''Chi'' (length) (尺), a traditional unit of length, about ⅓ meter *Chi (mythology) (螭), a dragon * Chi (surname) ...
tributary systems, forest cover was reduced from 42% in 1961 to 13% in 1993. Although this part of northeast Thailand has an annual rainfall of more than , a high evaporation rate means it is classified as a semi-arid region. Consequently, although the Mun and Chi basins drain 15% of the entire Mekong basin, they only contribute 6% of the average annual flow. Sandy and saline soils are the most common soil types, which makes much of the land unsuitable for wet rice cultivation. In spite of poor fertility, however, agriculture is intensive. Glutinous rice, maize, and cassava are the principal crops. Drought is by far the major hydrological hazard in this region. As the Mekong enters Cambodia, over 95% of its flows have already joined the river. From here on downstream the terrain is flat and water levels rather than flow volumes determine the movement of water across the landscape. The seasonal cycle of changing water levels at
Phnom Penh Phnom Penh is the Capital city, capital and List of cities and towns in Cambodia, most populous city of Cambodia. It has been the national capital since 1865 and has grown to become the nation's primate city and its political, economic, industr ...
results in the unique "flow reversal" of water into and out of the Great Lake via the Tonle Sap River. Phnom Penh also marks the beginning of the delta system of the Mekong River. Here the mainstream begins to break up into an increasing number of branches. In Cambodia, wet rice is the main crop and is grown on the flood plains of the Tonle Sap, Mekong, and Bassac (the Mekong delta distributary known as the Hậu in Vietnam) Rivers. More than half of Cambodia remains covered with mixed evergreen and deciduous broadleaf forest, but forest cover has decreased from 73% in 1973 to 63% in 1993. Here, the river landscape is flat. Small changes in water level determine the direction of water movement, including the large-scale reversal of flow into and out of the Tonle Sap basin from the Mekong River. The
Mekong Delta The Mekong Delta ( or simply ), also known as the Western Region () or South-western region (), is the list of regions of Vietnam, region in southwestern Vietnam where the Mekong, Mekong River River delta, approaches and empties into the sea th ...
in Vietnam is farmed intensively and has little natural vegetation left. Forest cover is less than 10%. In the Central Highlands of Vietnam, forest cover was reduced from over 95% in the 1950s to around 50% in the mid-1990s.
Agricultural expansion Agricultural expansion describes the growth of agricultural land ( arable land, pastures, etc.) especially in the 20th and 21st centuries. The agricultural expansion is often explained as a direct consequence of the global increase in food and e ...
and
population pressure Population pressure, a term summarizing the stress brought about by an excessive population density and its consequences, is used both in conjunction with human overpopulation and with other animal populations that suffer from too many individuals ...
are the major reasons for
land use Land use is an umbrella term to describe what happens on a parcel of land. It concerns the benefits derived from using the land, and also the land management actions that humans carry out there. The following categories are used for land use: fo ...
and landscape change. Both
drought A drought is a period of drier-than-normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D.  Jiang, A.  Khan, W.  Pokam Mba, D.  Rosenfeld, J. Tierney, ...
and
flood A flood is an overflow of water (list of non-water floods, or rarely other fluids) that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are of significant con ...
are common hazards in the Delta, which many people believe is the most sensitive to upstream hydrological change.


Water flow along its course

Table 1: Country share of Mekong River Basin (MRB) and water flows By taking into account hydrological regimes, physiography land use, and existing, planned and potential resource developments, the Mekong is divided into six distinct reaches: ''Reach 1: Lancang Jiang or Upper Mekong River in China''. In this part of the river, the major source of water flowing into the river comes from melting snow on the
Tibetan plateau The Tibetan Plateau, also known as the Qinghai–Tibet Plateau or Qingzang Plateau, is a vast elevated plateau located at the intersection of Central Asia, Central, South Asia, South, and East Asia. Geographically, it is located to the north of H ...
. This volume of water is sometimes called the "Yunnan component" and plays an important role in the low-flow hydrology of the lower mainstream. Even as far downstream as Kratie, the
Yunnan Yunnan; is an inland Provinces of China, province in Southwestern China. The province spans approximately and has a population of 47.2 million (as of 2020). The capital of the province is Kunming. The province borders the Chinese provinces ...
component makes up almost 30% of the average dry season flow. A major concern is that the ongoing and planned expansion of dams and reservoirs on the Mekong mainstream in Yunnan could have a significant effect on the low-flow regime of the lower Mekong basin system. ''Reach 2: Chiang Saen to
Vientiane Vientiane (, ) is the capital city, capital and largest city of Laos. Situated on the banks of the Mekong, Mekong River at the Thailand, Thai border, it comprises the five urban districts of Vientiane Prefecture and had a population of 840,000 ...
and
Nong Khai Nong Khai (, ) is a city in northeast Thailand. It is the capital of Nong Khai province. Nong Khai city is located in Mueang Nong Khai district. Nong Khai lies on the Mekong River, near the site of the First Thai–Lao Friendship Bridge, span ...
''. This reach is almost entirely mountainous and covered with natural forest although there has been widespread slash and burn agriculture. Although this reach cannot be termed "unspoiled", the hydrological response is perhaps the most natural and undisturbed of all the lower basin. Many hydrological aspects of the lower basin start to change rapidly at the downstream boundary of this reach. On 19 July 2019 this reach of the river dropped to its lowest level in a century. Officials are particularly concerned as July is in the wet season, when mainstream flows are abundant historically. Locals are blaming low water on the newly constructed Xayaburi Dam, as it enters its test phase prior to the start of commercial operation in October 2019. ''Reach 3: Vientiane and Nong Khai to
Pakse Pakse (or ''Pakxe''; French: ''Paksé''; Laotian: ປາກເຊ 'mouth of the river') is the capital and most populous city of the southern Laotian province of Champasak. Located at the confluence of the Xe Don and Mekong Rivers, the distri ...
''. The boundary between Reach 2 and 3 is where the Mekong hydrology starts to change. Reach 2 is dominated in both wet and dry seasons by the
Yunnan Yunnan; is an inland Provinces of China, province in Southwestern China. The province spans approximately and has a population of 47.2 million (as of 2020). The capital of the province is Kunming. The province borders the Chinese provinces ...
Component. Reach 3 is increasingly influenced by contributions from the large left bank tributaries in Laos, namely the
Nam Ngum Nam Ngum (, ) is a 354 km long river in Laos. It is a major tributary of the Mekong River. Geography The Nam Ngum originates from the northern mountainous region of Xiangkhoang Province and flows south through Vientiane Province joining t ...
, Nam Theun, Nam Hinboun, Se Bang Fai, Se Bang Hieng and Se Done Rivers. The Mun-
Chi __NOTOC__ Chi may refer to: __NOTOC__ Greek *Chi (letter) (Χ or χ), the twenty-second letter of the Greek alphabet Chinese * ''Chi'' (length) (尺), a traditional unit of length, about ⅓ meter *Chi (mythology) (螭), a dragon * Chi (surname) ...
river system from the right bank in
Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...
enters the mainstream within this reach. ''Reach 4: Pakse to Kratie''. The main hydrological contributions to the mainstream in this reach come from the Se Kong, Se San, and Sre Pok catchments. Together, these rivers make up the largest hydrological sub-component of the lower basin. Over 25% of the mean annual flow volume to the mainstream at Kratie comes from these three river basins. They are the key element in the hydrology of this part of the system, especially to the Tonle Sap flow reversal. ''Reach 5: Kratie to
Phnom Penh Phnom Penh is the Capital city, capital and List of cities and towns in Cambodia, most populous city of Cambodia. It has been the national capital since 1865 and has grown to become the nation's primate city and its political, economic, industr ...
''. This reach includes the hydraulic complexities of the Cambodian floodplain, the Tonle Sap and the Great Lake. By this stage, over 95% of the total flow has entered the Mekong system. The focus turns from hydrology and water discharge to the assessment of water level, over- bank storage and flooding and the hydrodynamics that determine the timing, duration and volume of the seasonal flow reversal into and out of the Great Lake. ''Reach 6: Phnom Penh to the
South China Sea The South China Sea is a marginal sea of the Western Pacific Ocean. It is bounded in the north by South China, in the west by the Indochinese Peninsula, in the east by the islands of Taiwan island, Taiwan and northwestern Philippines (mainly Luz ...
''. Here the mainstream divides into a complex and increasingly controlled and artificial system of branches and canals. Key features of flow behaviour are tidal influences and salt water intrusion. Every year, 35–50% of this reach is flooded during the rainy season. The impact of road embankments and similar infrastructure developments on the movement of this flood water is an increasingly important consequence of development. Table 2 summarises the mean annual flows along the mainstream. The mean annual flow entering the lower Mekong from China is equivalent to a relatively modest depth of runoff. Downstream of Vientiane this increases to over as the principal left bank tributaries enter the mainstream, mainly the Nam Ngum and Nam Theun. The flow level falls again, even with the right bank entry of the Mun-Chi system from Thailand. Although the Mun–Chi basin drains 20% of the lower system, average annual runoff is only . Runoff in the mainstream increases again with the entry from the left bank of the Se Kong from southern Laos and Se San and Sre Pok from Vietnam and Cambodia. Table 2: Lower Mekong Mainstream annual flow (1960 to 2004) at selected sites. Flows at Chiang Saen entering the lower basin from
Yunnan Yunnan; is an inland Provinces of China, province in Southwestern China. The province spans approximately and has a population of 47.2 million (as of 2020). The capital of the province is Kunming. The province borders the Chinese provinces ...
make up about 15% of the wet season flow at Kratie. This rises to 40% during the dry season, even this far downstream. During the wet season, the proportion of average flow coming from Yunnan rapidly decreases downstream of Chiang Saen, from 70% to less than 20% at Kratie. The dry season contribution from Yunnan is much more significant. The major portion of the balance comes from Laos, which points to a major distinction in the low-flow hydrology of the river. One fraction comes from melting snow in China and
Tibet Tibet (; ''Böd''; ), or Greater Tibet, is a region in the western part of East Asia, covering much of the Tibetan Plateau and spanning about . It is the homeland of the Tibetan people. Also resident on the plateau are other ethnic groups s ...
and the rest from over-season catchment storage in the lower basin. This has implications for the occurrence of drought conditions. For example, if runoff from melting snow in any given year is very low, then flows upstream of
Vientiane Vientiane (, ) is the capital city, capital and largest city of Laos. Situated on the banks of the Mekong, Mekong River at the Thailand, Thai border, it comprises the five urban districts of Vientiane Prefecture and had a population of 840,000 ...
-
Nong Khai Nong Khai (, ) is a city in northeast Thailand. It is the capital of Nong Khai province. Nong Khai city is located in Mueang Nong Khai district. Nong Khai lies on the Mekong River, near the site of the First Thai–Lao Friendship Bridge, span ...
would be lower. In a large river system like the Mekong, seasonal flows can be quite variable from year to year. Although the pattern of the annual hydrograph is fairly predictable, its magnitude is not. The average monthly flows along the mainstream are listed in Table 3, providing an indication of their range and variability from year to year. At
Pakse Pakse (or ''Pakxe''; French: ''Paksé''; Laotian: ປາກເຊ 'mouth of the river') is the capital and most populous city of the southern Laotian province of Champasak. Located at the confluence of the Xe Don and Mekong Rivers, the distri ...
, for example, flood season flows during August would exceed nine years out of ten, but exceed only one year in ten. Table 3: Mekong Mainstream monthly discharge, 1960–2004 (m3/s). There is little evidence from the last 45 years of data of any systematic changes in the hydrological regime of the Mekong.


Geology

The internal drainage patterns of the Mekong are unusual among those of large rivers. Most large river systems that drain the interiors of continents, such as the
Amazon Amazon most often refers to: * Amazon River, in South America * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon (company), an American multinational technology company * Amazons, a tribe of female warriors in Greek myth ...
, Congo, and
Mississippi Mississippi ( ) is a U.S. state, state in the Southeastern United States, Southeastern and Deep South regions of the United States. It borders Tennessee to the north, Alabama to the east, the Gulf of Mexico to the south, Louisiana to the s ...
, have relatively simple
dendritic Dendrite derives from the Greek word "dendron" meaning ( "tree-like"), and may refer to: Biology *Dendrite, a branched projection of a neuron *Dendrite (non-neuronal), branching projections of certain skin cells and immune cells Physical *Dendri ...
tributary networks that resemble a branching tree. Typically, such patterns develop in basins with gentle slopes where the underlying geological structure is fairly homogeneous and stable, exerting little or no control on
river morphology The terms river morphology and its synonym stream morphology are used to describe the shapes of river channels and how they change in shape and direction over time. The morphology of a river channel is a function of a number of processes and envir ...
. In marked contrast, the tributary networks of the
Salween The Salween is a Southeast Asian river, about long, flowing from the Tibetan Plateau south into the Andaman Sea. The Salween flows primarily within southwest China and eastern Myanmar, with a short section forming the border of Myanmar and Tha ...
,
Yangtze The Yangtze or Yangzi ( or ) is the longest river in Eurasia and the third-longest in the world. It rises at Jari Hill in the Tanggula Mountains of the Tibetan Plateau and flows including Dam Qu River the longest source of the Yangtze, i ...
, and particularly the Mekong, are complex with different sub-basins often exhibiting different, and distinct, drainage patterns. These complex drainage systems have developed in a setting where the underlying geological structure is heterogeneous and active, and is the major factor controlling the course of rivers and the landscapes they carve out. The elevation of the
Tibetan Plateau The Tibetan Plateau, also known as the Qinghai–Tibet Plateau or Qingzang Plateau, is a vast elevated plateau located at the intersection of Central Asia, Central, South Asia, South, and East Asia. Geographically, it is located to the north of H ...
during the Tertiary period was an important factor in the genesis of the south-west
monsoon A monsoon () is traditionally a seasonal reversing wind accompanied by corresponding changes in precipitation but is now used to describe seasonal changes in Atmosphere of Earth, atmospheric circulation and precipitation associated with annu ...
, which is the dominant climatic control influencing the hydrology of the Mekong Basin. Understanding the nature and timing of the elevation of Tibet (and the Central Highlands of Vietnam) therefore helps explain the provenance of sediment reaching the delta and the Tonle Sap Great Lake today. Studies of the provenance of sediments in the Mekong delta reveal a major switch in the source of sediments about eight million years ago (Ma). From 36 to 8 Ma the bulk (76%) of the sediments deposited in the delta came from erosion of the bedrock in the Three Rivers Area. From 8 Ma to the present, however, the contribution from the Three Rivers Area fell to 40%, while that from the Central Highlands rose from 11 to 51%. One of the most striking conclusions of provenance studies is the small contribution of sediment from the other parts of the Mekong basin, notably the Khorat Plateau, the uplands of northern Laos and northern Thailand, and the mountain ranges south of the Three Rivers area. The last glacial period came to an abrupt end about 19,000 years ago (19 ka) when sea levels rose rapidly, reaching a maximum of about above present levels in the early Holocene about 8 ka. At this time the shoreline of the
South China Sea The South China Sea is a marginal sea of the Western Pacific Ocean. It is bounded in the north by South China, in the west by the Indochinese Peninsula, in the east by the islands of Taiwan island, Taiwan and northwestern Philippines (mainly Luz ...
almost reached Phnom Penh and cores recovered from near Angkor Borei contained sediments deposited under the influence of tides, and salt marsh and mangrove swamp deposits. Sediments deposited in the Tonle Sap Great Lake about this time (7.9–7.3 ka) also show indications of marine influence, suggesting a connection to the South China Sea. Although the hydraulic relationships between the Mekong and the Tonle Sap Great Lake systems during the
Holocene The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene to ...
are not well understood, it is clear that between 9,000 and 7,500 years ago the confluence of the Tonle Sap and the Mekong was in proximity to the South China Sea. The present river morphology of the Mekong Delta developed over the last 6,000 years. During this period, the delta advanced over the continental shelf of the South China Sea, covering an area of more than . From 5.3 to 3.5 ka the delta advanced across a broad embayment formed between higher ground near the Cambodian border and uplands north of
Ho Chi Minh City Ho Chi Minh City (HCMC) ('','' TP.HCM; ), commonly known as Saigon (; ), is the most populous city in Vietnam with a population of around 14 million in 2025. The city's geography is defined by rivers and canals, of which the largest is Saigo ...
. During this phase of its development the delta was sheltered from the wave action of long-shore currents and was constructed largely through fluvial and tidal processes. At this time the delta was advancing at a rate of per year. After 3.5 ka, however, the delta had built out beyond the embayment and became subject to wave action and marine currents. These deflected deposition south-eastwards in the direction of the Cà Mau Peninsula, which is one of the most recent features of the delta. For much of its length the Mekong flows through bedrock channels, i.e., channels that are confined or constrained by bedrock or old alluvium in the bed and riverbanks. Geomorphologic features normally associated with the
alluvial Alluvium (, ) is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluvium is also sometimes called alluvial deposit. Alluvium is ...
stretches of mature rivers, such as
meander A meander is one of a series of regular sinuous curves in the Channel (geography), channel of a river or other watercourse. It is produced as a watercourse erosion, erodes the sediments of an outer, concave bank (cut bank, cut bank or river cl ...
s,
oxbow lake An oxbow lake is a U-shaped lake or stream pool, pool that forms when a wide meander of a river is meander cutoff, cut off, creating a free-standing body of water. The word "oxbow" can also refer to a U-shaped bend in a river or stream, whether ...
s, cut-offs, and extensive
floodplains A floodplain or flood plain or bottomlands is an area of land adjacent to a river. Floodplains stretch from the banks of a river channel to the base of the enclosing valley, and experience flooding during periods of high discharge.Goudie, ...
are restricted to a short stretch of the mainstream around
Vientiane Vientiane (, ) is the capital city, capital and largest city of Laos. Situated on the banks of the Mekong, Mekong River at the Thailand, Thai border, it comprises the five urban districts of Vientiane Prefecture and had a population of 840,000 ...
and downstream of Kratie where the river develops alluvial channels that are free of control exerted by the underlying bedrock. The Mekong basin is not normally considered a seismically active area as much of the basin is underlain by the relatively stable continental block. Nonetheless, the parts of the basin in northern
Laos Laos, officially the Lao People's Democratic Republic (LPDR), is the only landlocked country in Southeast Asia. It is bordered by Myanmar and China to the northwest, Vietnam to the east, Cambodia to the southeast, and Thailand to the west and ...
, northern
Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...
,
Myanmar Myanmar, officially the Republic of the Union of Myanmar; and also referred to as Burma (the official English name until 1989), is a country in northwest Southeast Asia. It is the largest country by area in Mainland Southeast Asia and has ...
and China do experience frequent earthquakes and tremors. The magnitude of these earthquakes rarely exceeds 6.5 on the
Richter magnitude scale The Richter scale (), also called the Richter magnitude scale, Richter's magnitude scale, and the Gutenberg–Richter scale, is a measure of the strength of earthquakes, developed by Charles Richter in collaboration with Beno Gutenberg, and pr ...
and is unlikely to cause material damage.


History

The difficulty of navigating the river has meant that it has divided, rather than united, the people who live near it. The earliest known settlements date to 210 BCE, with Ban Chiang being an excellent example of early Iron Age culture. The earliest recorded civilization was the 1st century
India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...
nised-Khmer culture of
Funan Funan (; , ; , Chữ Hán: ; ) was the name given by Chinese cartographers, geographers and writers to an ancient Khmer-Mon Indianized state—or, rather a loose network of states ''( Mandala)''—located in Mainland Southeast Asia covering ...
, in the Mekong delta. Excavations at Oc Eo, near modern
An Giang An Giang is a province of Vietnam. It is located in the Mekong Delta, in the country's southwestern part. Geography An Giang is located in the upper reaches of the Mekong Delta. The Hậu Giang and Tiền Giang branches of the Mekong River ...
, have found coins from as far away as the
Roman Empire The Roman Empire ruled the Mediterranean and much of Europe, Western Asia and North Africa. The Roman people, Romans conquered most of this during the Roman Republic, Republic, and it was ruled by emperors following Octavian's assumption of ...
. This was succeeded by the Khmer culture
Chenla Chenla or Zhenla ( zh, t=真臘, s=, 真腊, p=Zhēnlà, w=Chen-la; , ; ) is the Chinese designation for the vassal of the kingdom of Funan preceding the Khmer Empire that existed from around the late 6th to the early 9th century in Indochina. ...
state around the 5th century. The
Khmer empire The Khmer Empire was an empire in Southeast Asia, centered on Hydraulic empire, hydraulic cities in what is now northern Cambodia. Known as Kambuja (; ) by its inhabitants, it grew out of the former civilization of Chenla and lasted from 802 t ...
of
Angkor Angkor ( , 'capital city'), also known as Yasodharapura (; ),Headly, Robert K.; Chhor, Kylin; Lim, Lam Kheng; Kheang, Lim Hak; Chun, Chen. 1977. ''Cambodian-English Dictionary''. Bureau of Special Research in Modern Languages. The Catholic Uni ...
was the last great Indianized state in the region. From around the time of the fall of the Khmer empire, the Mekong was the front line between the emergent states of
Siam Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...
and Tonkin (North Vietnam), with Laos and Cambodia, then on the coast, torn between their influence. The first European to encounter the Mekong was the Portuguese António de Faria in 1540. A European map of 1563 depicts the river, although even by then little was known of the river upstream of the delta. European interest was sporadic: the
Spanish Spanish might refer to: * Items from or related to Spain: **Spaniards are a nation and ethnic group indigenous to Spain **Spanish language, spoken in Spain and many countries in the Americas **Spanish cuisine **Spanish history **Spanish culture ...
and Portuguese mounted some missionary and trade expeditions, while the Dutch Gerrit van Wuysthoff led an expedition up the river as far as Vientiane in 1641–42. The French invaded the region in the mid-19th century, capturing
Saigon Ho Chi Minh City (HCMC) ('','' TP.HCM; ), commonly known as Saigon (; ), is the most populous city in Vietnam with a population of around 14 million in 2025. The city's geography is defined by rivers and canals, of which the largest is Saigo ...
in 1861, and establishing a protectorate over Cambodia in 1863. The first systematic European exploration began with the French Mekong Expedition led by Ernest Doudard de Lagrée and
Francis Garnier Marie Joseph François Garnier (; 25 July 1839 – 21 December 1873) was a French officer, inspector of Indigenous Affairs of Cochinchina and explorer. He eventually became mission leader of the Mekong Expedition of 1866–68, Mekong Exploration C ...
, which ascended the river from its mouth to
Yunnan Yunnan; is an inland Provinces of China, province in Southwestern China. The province spans approximately and has a population of 47.2 million (as of 2020). The capital of the province is Kunming. The province borders the Chinese provinces ...
between 1866 and 1868. Their chief finding was that the Mekong had too many falls and rapids to ever be useful for
navigation Navigation is a field of study that focuses on the process of monitoring and controlling the motion, movement of a craft or vehicle from one place to another.Bowditch, 2003:799. The field of navigation includes four general categories: land navig ...
. The river's source was found by
Pyotr Kuzmich Kozlov Pyotr Kuzmich Kozlov (; 3 October 1863 in Dukhovshchina – 26 September 1935 in Peterhof) was a Russian and Soviet traveller and explorer who continued the studies of Nikolai Przhevalsky in Mongolia and Tibet. Biography Although prepared ...
in 1900. From 1893, the French extended their control of the river into Laos, establishing
French Indochina French Indochina (previously spelled as French Indo-China), officially known as the Indochinese Union and after 1941 as the Indochinese Federation, was a group of French dependent territories in Southeast Asia from 1887 to 1954. It was initial ...
by the first decade of the 20th century. This lasted until the
First First most commonly refers to: * First, the ordinal form of the number 1 First or 1st may also refer to: Acronyms * Faint Images of the Radio Sky at Twenty-Centimeters, an astronomical survey carried out by the Very Large Array * Far Infrared a ...
and
Second The second (symbol: s) is a unit of time derived from the division of the day first into 24 hours, then to 60 minutes, and finally to 60 seconds each (24 × 60 × 60 = 86400). The current and formal definition in the International System of U ...
Indochina Wars expelled French from its former colony and defeated US-supported governments. During the wars in Indochina in the 1970s, a significant quantity of explosives (sometimes, entire barges loaded with military ordnance) sank in the Cambodian section of the Mekong (as well as in the country's other waterways). Besides being a danger for fishermen, unexploded ordnance also creates problems for bridge and irrigation systems construction. As of 2013, Cambodian volunteers are being trained, with the support of the Office of Weapons Removal and Abatement within the US State Department Bureau of Political-Military Affairs, to conduct underwater explosive removal. The many maps of the river basin produced throughout recorded history reflect the region's changing human geography and politics. In 1995, Laos, Thailand, Cambodia, and Vietnam established the
Mekong River Commission The Mekong River Commission (MRC) is an "...inter-governmental organisation that works directly with the governments of Cambodia, Laos, Thailand, and Vietnam to jointly manage the shared water resources and the sustainable development of the Mekon ...
(MRC) to manage and coordinate the use and care of the Mekong. In 1996 China and Myanmar became "dialogue partners" of the MRC and the six countries now work together in a cooperative framework. In 2000, the governments of China, Laos, Thailand and Myanmar signed a ''Agreement on Commercial Navigation on Lancang-Mekong River among the Governments of the People's Republic of China, the Lao People's Democratic Republic, the Union of Myanmar and the Kingdom of Thailand'' which is the mechanism for cooperation with regard to riverine trade on the upper stretches of the Mekong.


Natural history

The Mekong basin is one of the richest areas of biodiversity in the world. Only the
Amazon Amazon most often refers to: * Amazon River, in South America * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon (company), an American multinational technology company * Amazons, a tribe of female warriors in Greek myth ...
boasts a higher level of bio-diversity. Biota estimates for the
Greater Mekong Subregion The Greater Mekong Subregion, (GMS) or just Greater Mekong, is a trans-national region of the Mekong River basin in Southeast Asia. The region is home to more than 300 million people. It came into being with the launch of a development program i ...
(GMS) include 20,000 plant species, 430 mammals, 1,200 birds, 800 reptiles and amphibians, and an estimated 850 freshwater fish species (excluding
euryhaline Euryhaline organisms are able to adapt to a wide range of salinities. An example of a euryhaline fish is the short-finned molly, '' Poecilia sphenops'', which can live in fresh water, brackish water, or salt water. The green crab ('' Carcinus m ...
species mainly found in salt or
brackish Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuari ...
water, as well as
introduced species An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived ther ...
). The most species rich orders among the freshwater fish in the river basin are cypriniforms (377 species) and
catfish Catfish (or catfishes; order (biology), order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Catfish are common name, named for their prominent barbel (anatomy), barbels, which resemble a cat's whiskers, though not ...
(92 species).Valbo-Jørgensen, J; Coates, D.; and Hortle, K. (2009). ''Fish diversity in the Mekong River basin.'' pp. 161–196 in: Campbell, I.C. (editor). The Mekong – Biophysical Environment of an International River Basin, 1st edition. Academic Press, Elsevier. New species are regularly described from the Mekong. In 2009, 145 species previously unknown to science were described from the region, including 29 fish species, 2 bird species, 10 reptiles, 5 mammals, 96 plants, and 6 amphibians. Between 1997 and 2015, an average of two new species per week were discovered in the region. The Mekong Region contains 16 WWF
Global 200 The Global 200 is the list of ecoregions identified by the World Wide Fund for Nature ( WWF), the global conservation organization, as priorities for conservation. According to WWF, an ecoregion is defined as a "relatively large unit of land or w ...
ecoregions, the greatest concentration of ecoregions in mainland Asia. No other river is home to so many species of very large fish. The biggest include three species of '' Probarbus'' barbs, which can grow up to and weigh , the giant freshwater stingray (''Himantura polylepis'', syn. ''H. chaophraya''), which can reach at least in length and in width, the giant pangasius (''Pangasius sanitwongsei''),
giant barb The giant barb, Siamese Giant carp, or simply Siamese carp (''Catlocarpio siamensis''; , ; , , , or , , ; Vietnamese: ''cá Hô'') is the largest species of cyprinid in the world. These migratory fish are found only in the Mae Klong, Mekong, and ...
(''Catlocarpio siamensis'') and the
endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...
Mekong giant catfish (''Pangasianodon gigas''). The last three can grow up to about in length and weigh . All of these have declined drastically because of dams, flood control, and overfishing. One species of
freshwater dolphin River dolphins are a polyphyletic group of fully aquatic mammals that reside exclusively in freshwater or brackish water. They are an informal grouping of dolphins, which itself is a paraphyletic group within the infraorder Cetacea. Extant rive ...
, the
Irrawaddy dolphin The Irrawaddy dolphin (''Orcaella brevirostris'') is a euryhaline species of oceanic dolphin found in scattered subpopulations near sea coasts and in estuaries and rivers in parts of the Bay of Bengal and Southeast Asia. It closely resembles the ...
(''Orcaella brevirostris''), was once common in the whole of the lower Mekong but is now very rare, with only 85 individuals remaining. Among other wetland mammals that have been living in and around the river are the
smooth-coated otter The smooth-coated otter (''Lutrogale perspicillata'') is a freshwater otter species from regions of South and Southwest Asia, with the majority of its numbers found in Southeast Asia. It has been ranked as " vulnerable" on the IUCN Red List since ...
(''Lutra perspicillata'') and
fishing cat The fishing cat (''Prionailurus viverrinus'') is a medium-sized wild cat of South and Southeast Asia. It has a deep yellowish-grey fur with black lines and spots. Adults have a head-to-body length of , with a long tail. Males are larger than f ...
(''Prionailurus viverrinus''). The endangered
Siamese crocodile The Siamese crocodile (''Crocodylus siamensis'') is a medium-sized freshwater crocodile native to Indonesia (Borneo and possibly Java), Brunei, East Malaysia, Laos, Cambodia, Myanmar, Thailand and Vietnam. The species is critically endangered and ...
(''Crocodylus siamensis'') occurs in small isolated pockets within the northern Cambodian and Laotian portions of the Mekong River. The
saltwater crocodile The saltwater crocodile (''Crocodylus porosus'') is a crocodilian native to saltwater habitats, brackish wetlands and freshwater rivers from India's east coast across Southeast Asia and the Sundaland to northern Australia and Micronesia. It ha ...
(''Crocodylus porosus'') once ranged from the Mekong Delta up the river into Tonle Sap and beyond but is now extinct in the river, along with being extinct in all of Vietnam and possibly even Cambodia.


Protected areas

*The headwaters of the Mekong in
Zadoi County Zadoi County (; zh, s=杂多县) is a county in the southwest of Qinghai Province, China, bordering the Tibet Autonomous Region The Tibet Autonomous Region (TAR), often shortened to Tibet in English or Xizang in Pinyin, Hanyu Pinyin, is a ...
, Qinghai, China, are protected in
Sanjiangyuan National Nature Reserve The Sanjiangyuan ( zh, c=三江源, l=Source of Three Rivers), is an area of the Tibetan Plateau in Qinghai province, China which contains the headwaters of three great rivers of Asia: the Yellow, the Yangtze, and the Mekong. Parts of the area w ...
. The name Sanjiangyuan means "the sources of the Three Rivers". The reserve also includes the headwaters of the
Yellow River The Yellow River, also known as Huanghe, is the second-longest river in China and the List of rivers by length, sixth-longest river system on Earth, with an estimated length of and a Drainage basin, watershed of . Beginning in the Bayan H ...
and the
Yangtze The Yangtze or Yangzi ( or ) is the longest river in Eurasia and the third-longest in the world. It rises at Jari Hill in the Tanggula Mountains of the Tibetan Plateau and flows including Dam Qu River the longest source of the Yangtze, i ...
. *The section of the river flowing through deep gorges in
Yunnan Yunnan; is an inland Provinces of China, province in Southwestern China. The province spans approximately and has a population of 47.2 million (as of 2020). The capital of the province is Kunming. The province borders the Chinese provinces ...
Province is part of the
Three Parallel Rivers of Yunnan Protected Areas The Three Parallel Rivers of Yunnan Protected Areas () is a UNESCO World Heritage Site in Yunnan province, China. It lies within the drainage basins of the upper reaches of the Jinsha (Yangtze), Lancang (Mekong) and Nujiang ( Salween) rivers, in ...
, a UNESCO
World Heritage Site World Heritage Sites are landmarks and areas with legal protection under an treaty, international treaty administered by UNESCO for having cultural, historical, or scientific significance. The sites are judged to contain "cultural and natural ...
. *The Tonle Sap Biosphere Reserve in Cambodia contains the largest lake in Southeast Asia. It is a UNESCO
Biosphere reserve A nature reserve (also known as a wildlife refuge, wildlife sanctuary, biosphere reserve or bioreserve, natural or nature preserve, or nature conservation area) is a protected area of importance for flora, fauna, funga, or features of geologic ...
.


Natural phenomena

The low tide level of the river in Cambodia is lower than the high tide level out at sea, and the flow of the Mekong inverts with the tides throughout its stretch in Vietnam and up to Phnom Penh. The very flat Mekong delta area in Vietnam is thus prone to flooding, especially in the provinces of An Giang and Dong Thap (Đồng Tháp), near the Cambodian border.


Fisheries

Aquatic biodiversity in the Mekong River system is the second highest in the world after the
Amazon Amazon most often refers to: * Amazon River, in South America * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon (company), an American multinational technology company * Amazons, a tribe of female warriors in Greek myth ...
. The Mekong boasts the most concentrated
biodiversity Biodiversity is the variability of life, life on Earth. It can be measured on various levels. There is for example genetic variability, species diversity, ecosystem diversity and Phylogenetics, phylogenetic diversity. Diversity is not distribut ...
per hectare of any river. The largest recorded freshwater fish, a giant freshwater stingray in 2022 and previously a Mekong giant catfish in 2005, were both caught in the Mekong River. The commercially valuable fish species in the Mekong are generally divided between "black fish", which inhabit low oxygen, slow moving, shallow waters, and "white fish", which inhabit well oxygenated, fast moving, deeper waters. People living within the Mekong River system generate many other sources of food and income from what are often termed "other aquatic animals" (OAAs) such as freshwater crabs, shrimp, snakes, turtles, and frogs. OAAs account for about 20% of the total Mekong catch. When fisheries are discussed, catches are typically divided between the wild capture fishery (i.e., fish and other aquatic animals caught in their natural habitat), and aquaculture (fish reared under controlled conditions). Wild capture fisheries play the most important role in supporting livelihoods. Wild capture fisheries are largely open access fisheries, which poor rural people can access for food and income. Broadly, there are three types of fish habitats in the Mekong: i) the river, including all the main tributaries, rivers in the major flood zone, and the Tonle Sap, which altogether yield about 30% of wild catch landings; ii) rain-fed wetlands outside the river-floodplain zone, including mainly rice paddies in formerly forested areas and usually inundated to about , yielding about 66% of wild catch landings; and iii) large water bodies outside the flood zone, including canals and reservoirs yielding about 4% of wild catch landings. The Mekong Basin has one of the world's largest and most productive inland fisheries. An estimated two million tonnes of fish are landed a year, in addition to almost 500,000 tonnes of other aquatic animals. Aquaculture yields about two million tonnes of fish a year. Hence, the lower Mekong basin yields about 4.5 million tonnes of fish and aquatic products annually. The total economic value of the fishery is between US$3.9 and US$7 billion a year. Wild capture fisheries alone have been valued at US$2 billion a year. This value increases considerably when the multiplier effect is included, but estimates vary widely. An estimated 2.56 million tonnes of inland fish and other aquatic animals are consumed in the lower Mekong every year. Aquatic resources make up between 47 and 80% of animal protein in rural diets for people who live in the Lower Mekong Basin. Fish are the cheapest source of animal protein in the region and any decline in the fishery is likely to significantly impact nutrition, especially among the poor. Fish are the staple of the diet in Laos and Cambodia, with around 80% of the Cambodian population's annual protein intake coming from fish caught in the Mekong River system, with no alternative source to replace it. An MRC report claims that dam projects on the Mekong River will reduce aquatic life by 40% by 2020, and predicted that 80% of fish will be depleted by 2040. Thailand will be impacted, as its fish stocks in the Mekong will decline by 55%, Laos will be reduced by 50%, Cambodia by 35%, and Vietnam by 30%. It is estimated that 40 million rural people, more than two-thirds of the rural population in the lower Mekong basin, are engaged in the wild capture fishery. Fisheries contribute significantly to a diversified livelihood strategy for many people, particularly the poor, who are highly dependent on the river and its resources for their livelihoods. They provide a principal form of income for numerous people and act as a safety net and coping strategy in times of poor agricultural harvests or other difficulties. In Laos alone, 71% of rural households (2.9 million people) rely on fisheries for either subsistence or additional cash income. Around the Tonle Sap Lake in Cambodia, more than 1.2 million people live in fishing communes and depend almost entirely on fishing for their livelihoods.


Dams

Dams in the Mekong reference those built for hydropower, irrigation and other uses (such as water supply). As of February 2024, dams in the Mekong are distributed as follows: Table 4: Dams in the Mekong River Basin Notes: HPPs = Hydropower Plants. Data calculated from the CGIAR Research Program on Water, Land and Ecosystems - Greater Mekong 'Dataset on the Dams of the Irrawaddy, Mekong, Red and Salween River Basins'. Only HPPs with an installed capacity of 15 Megawatts (MW) or more are included; and/or dams with a reservoir area of 0.5 km2 or more. There are also multiple HPPs under construction within the basin. As of February 2024, there is one under construction in Cambodia, three in the
TAR Tar is a dark brown or black viscous liquid of hydrocarbons and free carbon, obtained from a wide variety of organic materials through destructive distillation. Tar can be produced from coal, wood, petroleum, or peat. "a dark brown or black b ...
, and 14 in
Laos Laos, officially the Lao People's Democratic Republic (LPDR), is the only landlocked country in Southeast Asia. It is bordered by Myanmar and China to the northwest, Vietnam to the east, Cambodia to the southeast, and Thailand to the west and ...
. Of the Mekong's HPPs, 15 are located on the Mekong mainstream. Of these, 13 are in China, and two in Laos. An additional mainstream dam is currently under construction in Laos, and another in China.


Navigation

For thousands of years the Mekong River has been an important conduit for people and goods between the many towns on its banks. Traditional forms of trade in small boats linking communities continue today, however the river is also becoming an important link in international trade routes, connecting the six Mekong countries to each other, and also to the rest of the world. The Mekong is still a wild river and navigation conditions vary greatly along its length. Broadly, navigation of the river is divided between upper and lower Mekong, with the "upper" part of the river defined as the stretch north of the Khone Falls in southern Laos and the "lower" part as the stretch below these falls. Narrower and more turbulent sections of water in the upstream parts of the Mekong River, coupled with large annual water level variations continue to present a challenge to navigation. The seasonal variations in water level directly affect trade in this section of the river. Volumes of trade being shipped decrease by more than 50%, primarily due to the reduced draughts available during the low water season (June–January). Despite these difficulties, the Mekong River is already an important link in the transit chain between
Kunming Kunming is the capital and largest city of the province of Yunnan in China. The political, economic, communications and cultural centre of the province, Kunming is also the seat of the provincial government. During World War II, Kunming was a Ch ...
and
Bangkok Bangkok, officially known in Thai language, Thai as Krung Thep Maha Nakhon and colloquially as Krung Thep, is the capital and most populous city of Thailand. The city occupies in the Chao Phraya River delta in central Thailand and has an estim ...
with about 300,000 tonnes of goods shipped via this route each year. The volume of this trade is expected to increase by 8–11% per year. Port infrastructure is being expanded to accommodate the expected growth in traffic, with new facilities planned for Chiang Saen port. In Laos, 50 and 100 DWT vessels are operated for regional trade. Cargos carried are timber, agricultural products, and construction materials. Thailand imports a wide variety of products from China, including vegetables, fruit, agricultural products, and fertilisers. The main exports from Thailand are dried
longan ''Dimocarpus longan'', commonly known as the longan () and dragon's eye, is a tropical tree species that produces edible fruit. It is one of the better-known tropical members of the soapberry family Sapindaceae, to which the lychee and rambu ...
, fish oil, rubber products, and consumables. Nearly all the ships carrying cargo to and from Chiang Saen Port are 300 DWT Chinese flag vessels. Waterborne trade in the lower Mekong countries of Vietnam and Cambodia has grown significantly, with trends in container traffic at
Phnom Penh Phnom Penh is the Capital city, capital and List of cities and towns in Cambodia, most populous city of Cambodia. It has been the national capital since 1865 and has grown to become the nation's primate city and its political, economic, industr ...
port and general cargo through
Can Tho Can may refer to: Language * A verb for ability * A verb for probability Containers * A container used for food preservation in canning ** Aluminum can ** Drink can ** Steel and tin cans * Trash can * Oil can * Petrol can Music * Can (band ...
port both showing steady increases until 2009 when a decrease in cargo volumes can be attributed to the
2008 financial crisis The 2008 financial crisis, also known as the global financial crisis (GFC), was a major worldwide financial crisis centered in the United States. The causes of the 2008 crisis included excessive speculation on housing values by both homeowners ...
and a subsequent decline in demand for the export of garments to the US. In 2009, Mekong trade received a significant boost with the opening of a new deep-water port at Cai Mep in Vietnam. This new port has generated a renewed focus on the Mekong River as a trade route. The Cai Mep container terminals can accommodate vessels with a draught of , equivalent to the largest container ships in the world. These mother vessels sail directly to Europe or the United States, which means that goods can be shipped internationally to and from Phnom Penh with only a single transshipment at Cai Mep. As an international river, a number of agreements exist between the countries that share the Mekong to enable trade and passage between them. The most important of these, which address the full length of the river, are: *Agreement between China and Lao PDR on Freight and Passenger Transport along the Lancang–Mekong River, adopted in November 1994. *Agreement on the Cooperation for the Sustainable Development of the Mekong River Basin, Article 9, Freedom of Navigation, 5 April 1995, Chiang Rai. *Hanoi Agreement between Cambodia and Viet Nam on Waterway Transportation, 13 December 1998. *Agreement between and among the Governments of the Laos, Thailand, and Vietnam for Facilitation of Cross border Transport of Goods and People, (amended at Yangon, Myanmar), signed in Vientiane, 26 November 1999. *Agreement on Commercial Navigation on Lancang–Mekong River among the governments of China, Laos, Myanmar and Thailand, adopted at Tachileik, 20 April 2000. *Phnom Penh Agreement between Cambodia and Vietnam on the Transit of Goods, 7 September 2000. *New Agreement on Waterway Transportation between Vietnam and Cambodia, signed in Phnom Penh, 17 December 2009. In December 2016, the Thai cabinet of Prime Minister
Prayut Chan-o-cha Prayut Chan-o-cha (sometimes spelled Prayuth Chan-ocha; , ; born 21 March 1954) is a former Thai politician, army officer and dictator who became the 29th prime minister of Thailand after seizing power in the 2014 Thai coup d'état, 2014 coup ...
agreed "in principle" to a plan to dredge stretches of the Mekong and demolish rocky outcrops that are hindrances to easy navigation. The international Lancang-Mekong River navigation improvement plan for 2015–2025, conceived by China, Myanmar, Lao, and Thailand, aims to make the river more navigable for 500-tonne cargo vessels sailing the river from
Yunnan Yunnan; is an inland Provinces of China, province in Southwestern China. The province spans approximately and has a population of 47.2 million (as of 2020). The capital of the province is Kunming. The province borders the Chinese provinces ...
to
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 ...
, a distance of . China has been the driving force behind the demolition plan as it aims to expand trade in the area. The plan is split into two phases. The first phase, from 2015 to 2020, involves a survey, a design, and an assessment of the environmental and social impacts of the project. These have to be approved by the four countries involved: China, Laos, Myanmar, Thailand. The second phase (2020–2025) involves navigational improvements from Simao in China to 243 border posts in China and Myanmar, a distance of . Local groups have countered that native inhabitants already operate their boats year-round and that the plan to blast the rapids is not about making life better for local people, but about enabling year-round traffic of large Chinese commercial boats. On 4 February 2020, the Thai Cabinet voted to stop the project to blast and dredge of the river bed after Beijing failed to stump up the money for further surveys of the affected area.


Bridges

Construction of Myanmar–Laos Friendship Bridge started on 19 February 2013. The bridge will be long and have an wide two-lane motorway. The First Thai–Lao Friendship Bridge connects
Nong Khai Nong Khai (, ) is a city in northeast Thailand. It is the capital of Nong Khai province. Nong Khai city is located in Mueang Nong Khai district. Nong Khai lies on the Mekong River, near the site of the First Thai–Lao Friendship Bridge, span ...
city with
Vientiane Vientiane (, ) is the capital city, capital and largest city of Laos. Situated on the banks of the Mekong, Mekong River at the Thailand, Thai border, it comprises the five urban districts of Vientiane Prefecture and had a population of 840,000 ...
in Laos. The bridge opened on 8 April 1994. It has two lanes with a single railway line in the middle. On 20 March 2004, the Thai and Lao governments agreed to extend the railway to Tha Nalaeng in Laos. This extension has since been completed. The Second Thai–Lao Friendship Bridge connects Mukdahan to
Savannakhet Savannakhet (, ; ), officially named Kaysone Phomvihane (); since 2005 and previously known as ''Khanthaboury'' (; ), is a city in western Laos. It is the capital of Savannakhet Province. With a population of 125,760 (2018), it is the second-l ...
. The two-lane, , bridge opened to the public on 9 January 2007. The Third Thai–Lao Friendship Bridge opened for traffic on 11 November 2011, connecting
Nakhon Phanom Province Nakhon Phanom province (, , ; , ) is one of Thailand's seventy-six provinces (''changwat'') lies in upper northeastern Thailand also called Isan. Directly adjacent provinces are (from south clockwise): Mukdahan, Sakon Nakhon, and Bueng Kan. ...
(Thailand) and
Thakhek Thakhek (, ; , ), the capital of Khammouane Province, is a town in south-central Laos on the Mekong River and the administrative centre of the district with the same name. The Third Thai–Lao Friendship Bridge, linking Thakhek and Nakhon Phano ...
(Laos), as part of Asian Highway 3. The Chinese and Thai governments agreed to build the bridge and share the estimated US$33 million cost. The Fourth Thai–Lao Friendship Bridge opened to traffic on 11 December 2013. It links
Chiang Rai Province Chiang Rai (, ; , ) is one of Thailand's seventy-six Provinces of Thailand, provinces that lies in Northern Thailand#Regional classification of northern Thailand, upper northern Thailand and is Thailand's northernmost province. It is bordered ...
, Thailand with Ban Houayxay, Laos. There is one bridge over the Mekong entirely within Laos. Unlike the Friendship Bridges, it is not a border crossing. It is at
Pakse Pakse (or ''Pakxe''; French: ''Paksé''; Laotian: ປາກເຊ 'mouth of the river') is the capital and most populous city of the southern Laotian province of Champasak. Located at the confluence of the Xe Don and Mekong Rivers, the distri ...
in
Champasak Province Champasak (or Champassak, Champasack – Laotian language, Lao: ຈຳປາສັກ ) is a province in southwestern Laos, near the borders with Thailand and Cambodia. It is 1 of the 3 principalities that succeeded the Laos, Lao kingdom of Lan ...
. It is long, and was completed in 2000. ). The Kizuna Bridge is in
Cambodia Cambodia, officially the Kingdom of Cambodia, is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. It is bordered by Thailand to the northwest, Laos to the north, and Vietnam to the east, and has a coastline ...
, in the city of Kampong Cham, on the road linking Phnom Penh with the remote provinces of Ratanakiri and Mondolkiri, and Laos. The bridge opened for traffic on 11 December 2001. The Prek Tamak Bridge, north of Phnom Penh opened in 2010. Phnom Penh itself has no bridge under construction yet, although two new bridges have recently opened on the Tonle Sap, and the main bridge on the highway to Ho Chi Minh was duplicated in 2010. Another new bridge was built at Neak Leung on the Phnom Penh to Ho Chi Minh Highway 1 with Japanese government assistance, and opened in 2015. In
Vietnam Vietnam, officially the Socialist Republic of Vietnam (SRV), is a country at the eastern edge of mainland Southeast Asia, with an area of about and a population of over 100 million, making it the world's List of countries and depende ...
, the Mỹ Thuận Bridge was opened in 2000, crossing the first channel—the left, main branch of the Mekong, the Sông Tiền or Tiền Giang—near
Vĩnh Long Vĩnh Long ɨn˨˩˦:lawŋ˧˧is a city and the capital of Vĩnh Long Province in Vietnam's Mekong Delta. Geography Vĩnh Long covers and has a population of 200,120 (as of 2018). The name was spelled 永 隆 ("eternal prosperity") in the form ...
. Since 2008, the Rạch Miễu Bridge crosses it near Mỹ Tho, between the provinces of Tiền Giang and Bến Tre.
Cần Thơ Bridge Cần Thơ Bridge (), is a cable-stayed bridge over the Hậu ( Bassac) River, the largest distributary of the Mekong River, in the city of Cần Thơ in southern Vietnam. The bridge is 2.75 kilometres long (1.68 miles). It has a 6-lane carriagewa ...
crosses the second channel—the right, main distributary of the Mekong, the Bassac (Song Hau). Inaugurated in 2010, it is the longest main span cable-stayed bridge in Southeast Asia.


Environmental issues

Drought linked to a changing climate and dozens of hydroelectric dams are damaging the Mekong ecosystem. When drought ends and the inevitable floods begin, the effects of Mekong dams on flood pulse dynamics over the entire Lower Mekong are poorly understood. Sewage treatment is rudimentary in towns and urban areas throughout much of the Mekong's length, such as
Vientiane Vientiane (, ) is the capital city, capital and largest city of Laos. Situated on the banks of the Mekong, Mekong River at the Thailand, Thai border, it comprises the five urban districts of Vientiane Prefecture and had a population of 840,000 ...
in
Laos Laos, officially the Lao People's Democratic Republic (LPDR), is the only landlocked country in Southeast Asia. It is bordered by Myanmar and China to the northwest, Vietnam to the east, Cambodia to the southeast, and Thailand to the west and ...
. Water
pollution Pollution is the introduction of contaminants into the natural environment that cause harm. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the component ...
impacts the river's ecological integrity as a result. Much of the 8.3 billion
tonne The tonne ( or ; symbol: t) is a unit of mass equal to 1,000  kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton in the United States to distinguish it from the non-metric units of the s ...
s of plastic present on earth makes its way to the oceans. Ninety percent of plastic in the oceans is flushed there by just 10 rivers. The Mekong is one of them. A growing number of academics, NGOs, and scientists have urged the international community and the Mekong River Commission to reduce the use of hydropower, giving concerns of long-term sustainability. Some of them have urged an immediate moratorium on new construction of hydropower projects and a shift to solar and other forms of renewable energy, which are becoming more competitive and faster to install.
Sand mining Sand mining is the extraction of sand, mainly through an open pit (or sand pit) but sometimes mined from beaches and inland dunes or dredged from ocean and river beds. Sand is often used in manufacturing, for example as an abrasive or in conc ...
of the Mekong River in the countries Laos, Cambodia and Vietnam has led to various environmental impacts on both areas local and downstream to these operations due to the disturbance of the river's natural flow. These impacts include river embankment instability, reduced supply of vital floodwater and sediments to floodplains, increased salinity levels and both the disturbance and displacement of various species.


See also

*
Fair river sharing Fair river sharing is a kind of a fair division problem in which the waters of a river has to be divided among countries located along the river. It differs from other fair division problems in that the resource to be divided—the water—flows i ...
* GMS Environment Operations Center * Greater Mekong Sub-region Academic and Research Network *
Greater Mekong Subregion The Greater Mekong Subregion, (GMS) or just Greater Mekong, is a trans-national region of the Mekong River basin in Southeast Asia. The region is home to more than 300 million people. It came into being with the launch of a development program i ...
*
Indochina Mainland Southeast Asia (historically known as Indochina and the Indochinese Peninsula) is the continental portion of Southeast Asia. It lies east of the Indian subcontinent and south of Mainland China and is bordered by the Indian Ocean to th ...
*
Sekong River The Kong River, also known as the Sekong River (, ), is a river in Southeast Asia and an important tributary of the Mekong River. Course The river originates in Huế in Central Vietnam and flows through southern Laos and northeastern Cambo ...
* Mekong Expedition of 1866–1868 * Mekong River Basin Hydropower * Mekong River massacre 2011 killings on Mekong river * Stung Sen River


References


Further reading

* . * * . * . * * . * . * . *


External links


The WISDOM Project, a Water related Information System for the Mekong Delta

Mekong River Commission

CGIAR Research Program on Water, Land and Ecosystems - Greater Mekong
()
Mekong Watch

Countries of the Mekong River: The Greater Mekong Subregion
Asian Development Bank
Rivers Network : Mekong river blog
() {{Authority control Border rivers Cambodia–Laos border Ecoregions of Cambodia Ecoregions of China Ecoregions of Laos Ecoregions of Myanmar Ecoregions of Thailand Ecoregions of Vietnam Freshwater ecoregions International rivers of Asia Isan Laos–Myanmar border Laos–Thailand border Lowest points of countries Ramsar sites in Cambodia Rivers of Cambodia Rivers of Laos Rivers of Myanmar Rivers of Thailand Rivers of Tibet Rivers of Vietnam Rivers of Yunnan Tonlé Sap