Mekong

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Mekong_table_infobox_0

Mekong River

湄公河 (Méigōnghé) မဲခေါင်မြစ် (Megaung Myit) ແມ່ນ້ຳຂອງ (Maenam Khong) แม่น้ำโขง (Maenam Khong) ទន្លេមេគង្គ (Tonle Mekongk) Sông Mê Kông / Sông Cửu Long (九龍)Mekong_header_cell_0_0_0

LocationMekong_header_cell_0_1_0
CountryMekong_header_cell_0_2_0 China, Myanmar, Laos, Thailand, Cambodia, VietnamMekong_cell_0_2_1
Physical characteristicsMekong_header_cell_0_3_0
SourceMekong_header_cell_0_4_0 Lasaigongma (拉赛贡玛) SpringMekong_cell_0_4_1
locationMekong_header_cell_0_5_0 Mt. Guozongmucha (果宗木查), Zadoi, Yushu Tibetan Autonomous Prefecture, Qinghai, ChinaMekong_cell_0_5_1
coordinatesMekong_header_cell_0_6_0 Mekong_cell_0_6_1
elevationMekong_header_cell_0_7_0 5,224 m (17,139 ft)Mekong_cell_0_7_1
MouthMekong_header_cell_0_8_0 Mekong DeltaMekong_cell_0_8_1
locationMekong_header_cell_0_9_0 VietnamMekong_cell_0_9_1
elevationMekong_header_cell_0_10_0 0 m (0 ft)Mekong_cell_0_10_1
LengthMekong_header_cell_0_11_0 4,350 km (2,700 mi)Mekong_cell_0_11_1
Basin sizeMekong_header_cell_0_12_0 795,000 km (307,000 sq mi)Mekong_cell_0_12_1
DischargeMekong_header_cell_0_13_0 Mekong_cell_0_13_1
locationMekong_header_cell_0_14_0 South China SeaMekong_cell_0_14_1
averageMekong_header_cell_0_15_0 16,000 m/s (570,000 cu ft/s)Mekong_cell_0_15_1
minimumMekong_header_cell_0_16_0 1,400 m/s (49,000 cu ft/s)Mekong_cell_0_16_1
maximumMekong_header_cell_0_17_0 39,000 m/s (1,400,000 cu ft/s)Mekong_cell_0_17_1
Basin featuresMekong_header_cell_0_18_0
TributariesMekong_header_cell_0_19_0 Mekong_cell_0_19_1
leftMekong_header_cell_0_20_0 Nam Khan, Tha, Nam OuMekong_cell_0_20_1
rightMekong_header_cell_0_21_0 Mun, Tonle Sap, Kok, RuakMekong_cell_0_21_1
Protection StatusMekong_header_cell_0_22_0 Mekong_cell_0_22_1
Ramsar WetlandMekong_header_cell_0_23_0
Official nameMekong_header_cell_0_24_0 Middle Stretches of the Mekong River north of Stoeng TrengMekong_cell_0_24_1
DesignatedMekong_header_cell_0_25_0 23 June 1999Mekong_cell_0_25_1

The Mekong, or Mekong River, is a trans-boundary river in East Asia and Southeast Asia. Mekong_sentence_0

It is the world's twelfth longest river and the seventh longest in Asia. Mekong_sentence_1

Its estimated length is 4,350 km (2,703 mi), and it drains an area of 795,000 km (307,000 sq mi), discharging 475 km (114 cu mi) of water annually. Mekong_sentence_2

From the Tibetan Plateau the river runs through China, Myanmar, Laos, Thailand, Cambodia, and Vietnam. Mekong_sentence_3

The extreme seasonal variations in flow and the presence of rapids and waterfalls in the Mekong make navigation difficult. Mekong_sentence_4

Even so, the river is a major trade route between western China and Southeast Asia. Mekong_sentence_5

Names Mekong_section_0

Mekong is originally called Mae Nam Khong from a contracted form of Tai shortened to Mae Khong. Mekong_sentence_6

In Thai and Lao, Mae Nam ("Mother of Water[s]") is used for large rivers and Khong is the proper name referred to as "River Khong". Mekong_sentence_7

However, Khong is an archaic word meaning "river", loaned from Austroasiatic languages, such as Vietnamese sông (from *krong) and Mon kruŋ "river", which led to Chinese whose Old Chinese pronunciation has been reconstructed as /*kˤroŋ/ and which long served as the proper name of the Yangtze before becoming a generic word for major rivers. Mekong_sentence_8

To the early European traders, the Mekong River was also known as Mekon River, May-Kiang River and Cambodia River. Mekong_sentence_9

The local names for the river include: Mekong_sentence_10

Mekong_ordered_list_0

  1. From Tai:Mekong_item_0_0
  2. Other:Mekong_item_0_9
    • Vietnamese: Sông Cửu Long, (九龍 Nine Dragons River [ʂə̄wŋm kɨ̂w lāwŋm).Mekong_item_0_10
    • Khmer: ទន្លេធំ Tônlé Thum [tʊənlee tʰom ('Great River').Mekong_item_0_11
    • Khmuic: [ŏ̞m̥ kʰrɔːŋ̊], 'ŏ̞m̥' means 'river' or 'water', here it means 'river', 'kʰrɔːŋ̊' means 'canal'. So 'ŏ̞m̥ kʰrɔːŋ̊' means 'canal river'. In the ancient time Khmuic people called it '[ŏ̞m̥ kʰrɔːŋ̊ ɲă̞k̥]' or '[ŏ̞m̥ kʰrɔːŋ̊ ɟru̞ːʔ]' which means 'giant canal river' or 'deep canal river' respectively.Mekong_item_0_12

Course Mekong_section_1

The Mekong rises as the Za Qu (Tibetan: རྫ་ཆུ་, Wylie: rDza chu, ZYPY: Za qu; Chinese: 扎曲; pinyin: Zā Qū) and soon becomes known as the Lancang (simplified Chinese: 澜沧江; traditional Chinese: ; pinyin: Láncāng Jiāng, from the old name of Lao kingdom Lan Xang; the characters may also be literally understood as "turbulent green river"). Mekong_sentence_11

It originates in the "three rivers source area" on the Tibetan Plateau in the Sanjiangyuan National Nature Reserve. Mekong_sentence_12

The reserve protects the headwaters of, from north to south, the Yellow (Huang He), the Yangtze, and the Mekong Rivers. Mekong_sentence_13

It flows through the Tibetan Autonomous Region and then southeast into Yunnan Province, and then the Three Parallel Rivers Area in the Hengduan Mountains, along with the Yangtze to its east and the Salween River (Nu Jiang in Chinese) to its west. Mekong_sentence_14

Then the Mekong meets the China–Myanmar border and flows about 10 kilometres (6.2 mi) along that border until it reaches the tripoint of China, Myanmar and Laos. Mekong_sentence_15

From there it flows southwest and forms the border of Myanmar and Laos for about 100 kilometres (62 mi) until it arrives at the tripoint of Myanmar, Laos, and Thailand. Mekong_sentence_16

This is also the point of confluence between the Ruak River (which follows the Thai–Myanmar border) and the Mekong. Mekong_sentence_17

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. Mekong_sentence_18

From the Golden Triangle tripoint, the Mekong turns southeast to briefly form the border of Laos with Thailand. Mekong_sentence_19

Khon Pi Long is a series of rapids along a 1.6-kilometre section of the Mekong River dividing Chiang Rai and Bokeo Province in Laos. Mekong_sentence_20

The name of the rapids means 'where the ghost lost its way'. Mekong_sentence_21

It then turns east into the interior of Laos, flowing first east and then south for some 400 kilometres (250 mi) before meeting the border with Thailand again. Mekong_sentence_22

Once more, it defines the Laos-Thailand border for some 850 kilometres (530 mi) as it flows first east, passing the capital of Laos, Vientiane, then turns south. Mekong_sentence_23

A second time, the river leaves the border and flows east into Laos soon passing the city of Pakse. Mekong_sentence_24

Thereafter, it turns and runs more or less directly south, crossing into Cambodia. Mekong_sentence_25

At Phnom Penh the river is joined on the right bank by the river and lake system the Tonlé Sap. Mekong_sentence_26

When the Mekong is low, the Tonle Sap is a tributary: water flows from the lake and river into the Mekong. Mekong_sentence_27

When the Mekong floods, the flow reverses: the floodwaters of the Mekong flow up the Tonle Sap. Mekong_sentence_28

Immediately after the Sap River joins the Mekong by Phnom Penh, the Bassac River branches off the right (west) bank. Mekong_sentence_29

The Bassac River is the first and main distributary of the Mekong. Mekong_sentence_30

This is the beginning of the Mekong Delta. Mekong_sentence_31

The two rivers, the Bassac to the west and the Mekong to the east, enter Vietnam shortly after this. Mekong_sentence_32

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 or Tiền Giang. Mekong_sentence_33

In Vietnam, distributaries of the eastern (main, Mekong) branch include the Mỹ Tho River, the Ba Lai River, the Hàm Luông River, and the Cổ Chiên River. Mekong_sentence_34

Drainage basin Mekong_section_2

The Mekong Basin can be divided into two parts: the "upper Mekong basin" in Tibet, and the "lower Mekong basin" from Yunnan downstream from China to the South China Sea. Mekong_sentence_35

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 2,200 km (1,400 mi). Mekong_sentence_36

Here, it drops 4,500 metres (14,800 ft) before it enters the lower basin where the borders of Thailand, Laos, China, and Myanmar come together in the Golden Triangle. Mekong_sentence_37

Downstream from the Golden Triangle, the river flows for a further 2,600 km (1,600 mi) through Laos, Thailand, and Cambodia before entering the South China Sea via a complex delta system in Vietnam. Mekong_sentence_38

Upper basin Mekong_section_3

The upper basin makes up 24% of the total area and contributes 15–20% of the water that flows into the Mekong River. Mekong_sentence_39

The catchment here is steep and narrow. Mekong_sentence_40

Soil erosion has been a major problem and approximately 50% of the sediment in the river comes from the upper basin. Mekong_sentence_41

In Yunnan Province in China, the river and its tributaries are confined by narrow, deep gorges. Mekong_sentence_42

The tributary river systems in this part of the basin are small. Mekong_sentence_43

Only 14 have catchment areas that exceed 1,000 km (390 sq mi), yet the greatest amount of loss of forest cover in the entire river system per square kilometer has occurred in this region due to heavy unchecked demand for natural resources. Mekong_sentence_44

In the south of Yunnan, in Simao and Xishuangbanna Prefectures, the river changes as the valley opens out, the floodplain becomes wider, and the river becomes wider and slower. Mekong_sentence_45

Lower basin Mekong_section_4

Major tributary systems develop in the lower basin. Mekong_sentence_46

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. Mekong_sentence_47

The first group are left bank tributaries that drain the high rainfall areas of Laos. Mekong_sentence_48

The second group are those on the right bank, mainly the Mun and Chi Rivers, that drain a large part of northeast Thailand. Mekong_sentence_49

Laos lies almost entirely within the lower Mekong basin. Mekong_sentence_50

Its climate, landscape and land use are the major factors shaping the hydrology of the river. Mekong_sentence_51

The mountainous landscape means that only 16% of the country is farmed under lowland terrace or upland shifting cultivation. Mekong_sentence_52

With upland shifting agriculture (slash and burn), soils recover within 10 to 20 years but the vegetation does not. Mekong_sentence_53

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. Mekong_sentence_54

As elsewhere in the basin, forest cover has been steadily reduced during the last three decades by shifting agriculture and permanent agriculture. Mekong_sentence_55

The cumulative impacts of these activities on the river regime have not been measured. Mekong_sentence_56

However, the hydrological impacts of land cover changes induced by the Vietnam War were quantified in two sub-catchments of the lower Mekong River basin. Mekong_sentence_57

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. Mekong_sentence_58

On the Khorat Plateau, which includes the Mun and Chi tributary systems, forest cover was reduced from 42% in 1961 to 13% in 1993. Mekong_sentence_59

Although this part of northeast Thailand has an annual rainfall of more than 1,000 mm, a high evaporation rate means it is classified as a semi-arid region. Mekong_sentence_60

Consequently, although the Mun and Chi basins drain 15% of the entire Mekong basin, they only contribute 6% of the average annual flow. Mekong_sentence_61

Sandy and saline soils are the most common soil types, which makes much of the land unsuitable for wet rice cultivation. Mekong_sentence_62

In spite of poor fertility, however, agriculture is intensive. Mekong_sentence_63

Glutinous rice, maize, and cassava are the principal crops. Mekong_sentence_64

Drought is by far the major hydrological hazard in this region. Mekong_sentence_65

As the Mekong enters Cambodia, over 95% of its flows have already joined the river. Mekong_sentence_66

From here on downstream the terrain is flat and water levels rather than flow volumes determine the movement of water across the landscape. Mekong_sentence_67

The seasonal cycle of changing water levels at Phnom Penh results in the unique "flow reversal" of water into and out of the Great Lake via the Tonle Sap River. Mekong_sentence_68

Phnom Penh also marks the beginning of the delta system of the Mekong River. Mekong_sentence_69

Here the mainstream begins to break up into an increasing number of branches. Mekong_sentence_70

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. Mekong_sentence_71

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. Mekong_sentence_72

Here, the river landscape is flat. Mekong_sentence_73

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. Mekong_sentence_74

The Mekong delta in Vietnam is farmed intensively and has little natural vegetation left. Mekong_sentence_75

Forest cover is less than 10%. Mekong_sentence_76

In the Central Highlands of Vietnam, forest cover was reduced from over 95% in the 1950s to around 50% in the mid-1990s. Mekong_sentence_77

Agricultural expansion and population pressure are the major reasons for land use and landscape change. Mekong_sentence_78

Both drought and flood are common hazards in the Delta, which many people believe is the most sensitive to upstream hydrological change. Mekong_sentence_79

Water flow along its course Mekong_section_5

Table 1: Country share of Mekong River Basin (MRB) and water flows Mekong_sentence_80

Mekong_table_general_1

Mekong_cell_1_0_0 ChinaMekong_cell_1_0_1 MyanmarMekong_cell_1_0_2 LaosMekong_cell_1_0_3 ThailandMekong_cell_1_0_4 CambodiaMekong_cell_1_0_5 VietnamMekong_cell_1_0_6 TotalMekong_cell_1_0_7
Basin area (km)Mekong_cell_1_1_0 165,000Mekong_cell_1_1_1 24,000Mekong_cell_1_1_2 202,000Mekong_cell_1_1_3 184,000Mekong_cell_1_1_4 155,000Mekong_cell_1_1_5 65,000Mekong_cell_1_1_6 795,000Mekong_cell_1_1_7
Catchment as % of MRBMekong_cell_1_2_0 21Mekong_cell_1_2_1 3Mekong_cell_1_2_2 25Mekong_cell_1_2_3 23Mekong_cell_1_2_4 20Mekong_cell_1_2_5 8Mekong_cell_1_2_6 100Mekong_cell_1_2_7
Flow as % of MRBMekong_cell_1_3_0 16Mekong_cell_1_3_1 2Mekong_cell_1_3_2 35Mekong_cell_1_3_3 18Mekong_cell_1_3_4 18Mekong_cell_1_3_5 11Mekong_cell_1_3_6 100Mekong_cell_1_3_7

By taking into account hydrological regimes, physiography land use, and existing, planned and potential resource developments, the Mekong is divided into six distinct reaches: Mekong_sentence_81

Reach 1: Lancang Jiang or Upper Mekong River in China. Mekong_sentence_82

In this part of the river, the major source of water flowing into the river comes from melting snow on the Tibetan plateau. Mekong_sentence_83

This volume of water is sometimes called the "Yunnan component" and plays an important role in the low-flow hydrology of the lower mainstream. Mekong_sentence_84

Even as far downstream as Kratie, the Yunnan component makes up almost 30% of the average dry season flow. Mekong_sentence_85

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. Mekong_sentence_86

Reach 2: Chiang Saen to Vientiane and Nong Khai. Mekong_sentence_87

This reach is almost entirely mountainous and covered with natural forest although there has been widespread slash and burn agriculture. Mekong_sentence_88

Although this reach cannot be termed "unspoiled", the hydrological response is perhaps the most natural and undisturbed of all the lower basin. Mekong_sentence_89

Many hydrological aspects of the lower basin start to change rapidly at the downstream boundary of this reach. Mekong_sentence_90

On 19 July 2019 this reach of the river dropped to its lowest level in a century. Mekong_sentence_91

Officials are particularly concerned as July is in the wet season, when mainstream flows are abundant historically. Mekong_sentence_92

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. Mekong_sentence_93

Reach 3: Vientiane and Nong Khai to Pakse. Mekong_sentence_94

The boundary between Reach 2 and 3 is where the Mekong hydrology starts to change. Mekong_sentence_95

Reach 2 is dominated in both wet and dry seasons by the Yunnan Component. Mekong_sentence_96

Reach 3 is increasingly influenced by contributions from the large left bank tributaries in Laos, namely the Nam Ngum, Nam Theun, Nam Hinboun, Se Bang Fai, Se Bang Hieng, and Se Done Rivers. Mekong_sentence_97

The Mun-Chi river system from the right bank in Thailand enters the mainstream within this reach. Mekong_sentence_98

Reach 4: Pakse to Kratie. Mekong_sentence_99

The main hydrological contributions to the mainstream in this reach come from the Se Kong, Se San, and Sre Pok catchments. Mekong_sentence_100

Together, these rivers make up the largest hydrological sub-component of the lower basin. Mekong_sentence_101

Over 25% of the mean annual flow volume to the mainstream at Kratie comes from these three river basins. Mekong_sentence_102

They are the key element in the hydrology of this part of the system, especially to the Tonle Sap flow reversal. Mekong_sentence_103

Reach 5: Kratie to Phnom Penh. Mekong_sentence_104

This reach includes the hydraulic complexities of the Cambodian floodplain, the Tonle Sap and the Great Lake. Mekong_sentence_105

By this stage, over 95% of the total flow has entered the Mekong system. Mekong_sentence_106

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. Mekong_sentence_107

Reach 6: Phnom Penh to the South China Sea. Mekong_sentence_108

Here the mainstream divides into a complex and increasingly controlled and artificial system of branches and canals. Mekong_sentence_109

Key features of flow behaviour are tidal influences and salt water intrusion. Mekong_sentence_110

Every year, 35–50% of this reach is flooded during the rainy season. Mekong_sentence_111

The impact of road embankments and similar infrastructure developments on the movement of this flood water is an increasingly important consequence of development. Mekong_sentence_112

Table 2 summarises the mean annual flows along the mainstream. Mekong_sentence_113

The mean annual flow entering the lower Mekong from China is equivalent to a relatively modest 450 mm depth of runoff. Mekong_sentence_114

Downstream of Vientiane this increases to over 600 mm as the principal left bank tributaries enter the mainstream, mainly the Nam Ngum and Nam Theun. Mekong_sentence_115

The flow level falls again, even with the right bank entry of the Mun-Chi system from Thailand. Mekong_sentence_116

Although the Mun–Chi basin drains 20% of the lower system, average annual runoff is only 250 mm. Mekong_sentence_117

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. Mekong_sentence_118

Table 2: Lower Mekong Mainstream annual flow (1960 to 2004) at selected sites. Mekong_sentence_119

Mekong_table_general_2

Mainstream siteMekong_header_cell_2_0_0 Catchment area (km)Mekong_header_cell_2_0_1 Mean annual flowMekong_header_cell_2_0_2 Mekong_header_cell_2_0_3 Mekong_header_cell_2_0_4 as % total MekongMekong_header_cell_2_0_5
Mekong_cell_2_1_0 Mekong_cell_2_1_1 Discharge m/sMekong_cell_2_1_2 Volume kmMekong_cell_2_1_3 Runoff (mm)Mekong_cell_2_1_4 Mekong_cell_2_1_5
Chiang SaenMekong_cell_2_2_0 189,000Mekong_cell_2_2_1 2,700Mekong_cell_2_2_2 85Mekong_cell_2_2_3 450Mekong_cell_2_2_4 19Mekong_cell_2_2_5
Luang PrabangMekong_cell_2_3_0 268,000Mekong_cell_2_3_1 3,900Mekong_cell_2_3_2 123Mekong_cell_2_3_3 460Mekong_cell_2_3_4 27Mekong_cell_2_3_5
Chiang KhanMekong_cell_2_4_0 292,000Mekong_cell_2_4_1 4,200Mekong_cell_2_4_2 133Mekong_cell_2_4_3 460Mekong_cell_2_4_4 29Mekong_cell_2_4_5
VientianeMekong_cell_2_5_0 299,000Mekong_cell_2_5_1 4,400Mekong_cell_2_5_2 139Mekong_cell_2_5_3 460Mekong_cell_2_5_4 30Mekong_cell_2_5_5
Nong KhaiMekong_cell_2_6_0 302,000Mekong_cell_2_6_1 4,500Mekong_cell_2_6_2 142Mekong_cell_2_6_3 470Mekong_cell_2_6_4 31Mekong_cell_2_6_5
Nakhon PhanomMekong_cell_2_7_0 373,000Mekong_cell_2_7_1 7,100Mekong_cell_2_7_2 224Mekong_cell_2_7_3 600Mekong_cell_2_7_4 49Mekong_cell_2_7_5
MukdahanMekong_cell_2_8_0 391,000Mekong_cell_2_8_1 7,600Mekong_cell_2_8_2 240Mekong_cell_2_8_3 610Mekong_cell_2_8_4 52Mekong_cell_2_8_5
PakseMekong_cell_2_9_0 545,000Mekong_cell_2_9_1 9,700Mekong_cell_2_9_2 306Mekong_cell_2_9_3 560Mekong_cell_2_9_4 67Mekong_cell_2_9_5
Stung TrengMekong_cell_2_10_0 635,000Mekong_cell_2_10_1 13,100Mekong_cell_2_10_2 413Mekong_cell_2_10_3 650Mekong_cell_2_10_4 90Mekong_cell_2_10_5
KratiéMekong_cell_2_11_0 646,000Mekong_cell_2_11_1 13,200Mekong_cell_2_11_2 416Mekong_cell_2_11_3 640Mekong_cell_2_11_4 91Mekong_cell_2_11_5
Basin TotalMekong_cell_2_12_0 760,000Mekong_cell_2_12_1 14,500Mekong_cell_2_12_2 457Mekong_cell_2_12_3 600Mekong_cell_2_12_4 100Mekong_cell_2_12_5

Flows at Chiang Saen entering the lower basin from Yunnan make up about 15% of the wet season flow at Kratie. Mekong_sentence_120

This rises to 40% during the dry season, even this far downstream. Mekong_sentence_121

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. Mekong_sentence_122

The dry season contribution from Yunnan is much more significant. Mekong_sentence_123

The major portion of the balance comes from Laos, which points to a major distinction in the low-flow hydrology of the river. Mekong_sentence_124

One fraction comes from melting snow in China and Tibet and the rest from over-season catchment storage in the lower basin. Mekong_sentence_125

This has implications for the occurrence of drought conditions. Mekong_sentence_126

For example, if runoff from melting snow in any given year is very low, then flows upstream of Vientiane-Nong Khai would be lower. Mekong_sentence_127

In a large river system like the Mekong, seasonal flows can be quite variable from year to year. Mekong_sentence_128

Although the pattern of the annual hydrograph is fairly predictable, its magnitude is not. Mekong_sentence_129

The average monthly flows along the mainstream are listed in Table 3, providing an indication of their range and variability from year to year. Mekong_sentence_130

At Pakse, for example, flood season flows during August would exceed 20,000 cubic metres per second nine years out of ten, but exceed 34,000 m/s only one year in ten. Mekong_sentence_131

Table 3: Mekong Mainstream monthly discharge, 1960–2004 (m/s). Mekong_sentence_132

Mekong_table_general_3

MonthMekong_header_cell_3_0_0 Chiang SaenMekong_header_cell_3_0_1 Luang PrabangMekong_header_cell_3_0_2 VientianeMekong_header_cell_3_0_3 Nakhon PhanomMekong_header_cell_3_0_4 MukdahanMekong_header_cell_3_0_5 PakseMekong_header_cell_3_0_6 KratieMekong_header_cell_3_0_7
JanMekong_cell_3_1_0 1,150Mekong_cell_3_1_1 1,690Mekong_cell_3_1_2 1,760Mekong_cell_3_1_3 2,380Mekong_cell_3_1_4 2,370Mekong_cell_3_1_5 2,800Mekong_cell_3_1_6 3,620Mekong_cell_3_1_7
FebMekong_cell_3_2_0 930Mekong_cell_3_2_1 1,280Mekong_cell_3_2_2 1,370Mekong_cell_3_2_3 1,860Mekong_cell_3_2_4 1,880Mekong_cell_3_2_5 2,170Mekong_cell_3_2_6 2,730Mekong_cell_3_2_7
MarMekong_cell_3_3_0 830Mekong_cell_3_3_1 1,060Mekong_cell_3_3_2 1,170Mekong_cell_3_3_3 1,560Mekong_cell_3_3_4 1,600Mekong_cell_3_3_5 1,840Mekong_cell_3_3_6 2,290Mekong_cell_3_3_7
AprMekong_cell_3_4_0 910Mekong_cell_3_4_1 1,110Mekong_cell_3_4_2 1,190Mekong_cell_3_4_3 1,530Mekong_cell_3_4_4 1,560Mekong_cell_3_4_5 1,800Mekong_cell_3_4_6 2,220Mekong_cell_3_4_7
MayMekong_cell_3_5_0 1,300Mekong_cell_3_5_1 1,570Mekong_cell_3_5_2 1,720Mekong_cell_3_5_3 2,410Mekong_cell_3_5_4 2,430Mekong_cell_3_5_5 2,920Mekong_cell_3_5_6 3,640Mekong_cell_3_5_7
JunMekong_cell_3_6_0 2,460Mekong_cell_3_6_1 3,110Mekong_cell_3_6_2 3,410Mekong_cell_3_6_3 6,610Mekong_cell_3_6_4 7,090Mekong_cell_3_6_5 8,810Mekong_cell_3_6_6 11,200Mekong_cell_3_6_7
JulMekong_cell_3_7_0 4,720Mekong_cell_3_7_1 6,400Mekong_cell_3_7_2 6,920Mekong_cell_3_7_3 12,800Mekong_cell_3_7_4 13,600Mekong_cell_3_7_5 16,600Mekong_cell_3_7_6 22,200Mekong_cell_3_7_7
AugMekong_cell_3_8_0 6,480Mekong_cell_3_8_1 9,920Mekong_cell_3_8_2 11,000Mekong_cell_3_8_3 19,100Mekong_cell_3_8_4 20,600Mekong_cell_3_8_5 26,200Mekong_cell_3_8_6 35,500Mekong_cell_3_8_7
SepMekong_cell_3_9_0 5,510Mekong_cell_3_9_1 8,990Mekong_cell_3_9_2 10,800Mekong_cell_3_9_3 18,500Mekong_cell_3_9_4 19,800Mekong_cell_3_9_5 26,300Mekong_cell_3_9_6 36,700Mekong_cell_3_9_7
OctMekong_cell_3_10_0 3,840Mekong_cell_3_10_1 5,750Mekong_cell_3_10_2 6,800Mekong_cell_3_10_3 10,200Mekong_cell_3_10_4 10,900Mekong_cell_3_10_5 15,400Mekong_cell_3_10_6 22,000Mekong_cell_3_10_7
NovMekong_cell_3_11_0 2,510Mekong_cell_3_11_1 3,790Mekong_cell_3_11_2 4,230Mekong_cell_3_11_3 5,410Mekong_cell_3_11_4 5,710Mekong_cell_3_11_5 7,780Mekong_cell_3_11_6 10,900Mekong_cell_3_11_7
DecMekong_cell_3_12_0 1,590Mekong_cell_3_12_1 2,400Mekong_cell_3_12_2 2,560Mekong_cell_3_12_3 3,340Mekong_cell_3_12_4 3,410Mekong_cell_3_12_5 4,190Mekong_cell_3_12_6 5,710Mekong_cell_3_12_7

There is little evidence from the last 45 years of data of any systematic changes in the hydrological regime of the Mekong. Mekong_sentence_133

Geology Mekong_section_6

The internal drainage patterns of the Mekong are unusual when compared to those of other large rivers. Mekong_sentence_134

Most large river systems that drain the interiors of continents, such as the Amazon, Congo, and Mississippi, have relatively simple tributary networks that resemble a branching tree. Mekong_sentence_135

Typically, such patterns develop in basins with gentle slopes where the underlying geological structure is fairly homogenous and stable, exerting little or no control on river morphology. Mekong_sentence_136

In marked contrast, the tributary networks of the Salween, Yangtze, and particularly the Mekong, are complex with different sub-basins often exhibiting different, and distinct, drainage patterns. Mekong_sentence_137

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. Mekong_sentence_138

The elevation of the Tibetan Plateau during the Tertiary period was an important factor in the genesis of the south-west monsoon, which is the dominant climatic control influencing the hydrology of the Mekong Basin. Mekong_sentence_139

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. Mekong_sentence_140

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). Mekong_sentence_141

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. Mekong_sentence_142

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%. Mekong_sentence_143

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. Mekong_sentence_144

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 4.5 m above present levels in the early Holocene about 8 ka. Mekong_sentence_145

At this time the shoreline of the South China Sea 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. Mekong_sentence_146

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. Mekong_sentence_147

Although the hydraulic relationships between the Mekong and the Tonle Sap Great Lake systems during the Holocene 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. Mekong_sentence_148

The present river morphology of the Mekong Delta developed over the last 6,000 years. Mekong_sentence_149

During this period, the delta advanced 200 km over the continental shelf of the South China Sea, covering an area of more than 62,500 km. Mekong_sentence_150

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. Mekong_sentence_151

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. Mekong_sentence_152

At this time the delta was advancing at a rate of 17–18 m per year. Mekong_sentence_153

After 3.5 ka, however, the delta had built out beyond the embayment and became subject to wave action and marine currents. Mekong_sentence_154

These deflected deposition south-eastwards in the direction of the Cà Mau Peninsula, which is one of the most recent features of the delta. Mekong_sentence_155

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. Mekong_sentence_156

Geomorphologic features normally associated with the alluvial stretches of mature rivers, such as meanders, oxbow lakes, cut-offs, and extensive floodplains are restricted to a short stretch of the mainstream around Vientiane and downstream of Kratie where the river develops alluvial channels that are free of control exerted by the underlying bedrock. Mekong_sentence_157

The Mekong basin is not normally considered a seismically active area as much of the basin is underlain by the relatively stable continental block. Mekong_sentence_158

Nonetheless, the parts of the basin in northern Laos, northern Thailand, Myanmar and China do experience frequent earthquakes and tremors. Mekong_sentence_159

The magnitude of these earthquakes rarely exceeds 6.5 on the Richter magnitude scale and is unlikely to cause material damage. Mekong_sentence_160

History Mekong_section_7

The difficulty of navigating the river has meant that it has divided, rather than united, the people who live near it. Mekong_sentence_161

The earliest known settlements date to 210 BCE, with Ban Chiang being an excellent example of early Iron Age culture. Mekong_sentence_162

The earliest recorded civilization was the 1st century Indianised-Khmer culture of Funan, in the Mekong delta. Mekong_sentence_163

Excavations at Oc Eo, near modern An Giang, have found coins from as far away as the Roman Empire. Mekong_sentence_164

This was succeeded by the Khmer culture Chenla state around the 5th century. Mekong_sentence_165

The Khmer empire of Angkor was the last great Indianized state in the region. Mekong_sentence_166

From around the time of the fall of the Khmer empire, the Mekong was the front line between the emergent states of Siam and Tonkin (North Vietnam), with Laos and Cambodia, then on the coast, torn between their influence. Mekong_sentence_167

The first European to encounter the Mekong was the Portuguese Antonio de Faria in 1540. Mekong_sentence_168

A European map of 1563 depicts the river, although even by then little was known of the river upstream of the delta. Mekong_sentence_169

European interest was sporadic: the Spanish 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. Mekong_sentence_170

The French invaded the region in the mid-19th century, capturing Saigon in 1861, and establishing a protectorate over Cambodia in 1863. Mekong_sentence_171

The first systematic European exploration began with the French Mekong Expedition led by Ernest Doudard de Lagrée and Francis Garnier, which ascended the river from its mouth to Yunnan between 1866 and 1868. Mekong_sentence_172

Their chief finding was that the Mekong had too many falls and rapids to ever be useful for navigation. Mekong_sentence_173

The river's source was found by Pyotr Kuzmich Kozlov in 1900. Mekong_sentence_174

From 1893, the French extended their control of the river into Laos, establishing French Indochina by the first decade of the 20th century. Mekong_sentence_175

This lasted until the First and Second Indochina Wars expelled French from its former colony and defeated US-supported governments. Mekong_sentence_176

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). Mekong_sentence_177

Besides being a danger for fishermen, unexploded ordnance also creates problems for bridge and irrigation systems construction. Mekong_sentence_178

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. Mekong_sentence_179

In 1995, Laos, Thailand, Cambodia, and Vietnam established the Mekong River Commission (MRC) to manage and coordinate the use and care of the Mekong. Mekong_sentence_180

In 1996 China and Myanmar became "dialogue partners" of the MRC and the six countries now work together in a cooperative framework. Mekong_sentence_181

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. Mekong_sentence_182

Natural history Mekong_section_8

The Mekong basin is one of the richest areas of biodiversity in the world. Mekong_sentence_183

Only the Amazon boasts a higher level of bio-diversity. Mekong_sentence_184

Biota estimates for the Greater Mekong Subregion (GMS) include 20,000 plant species, 430 mammals, 1,200 birds, 800 reptiles and amphibians, and an estimated 850 freshwater fish species (excluding euryhaline species mainly found in salt or brackish water, as well as introduced species). Mekong_sentence_185

The most species rich orders among the freshwater fish in the river basin are cypriniforms (377 species) and catfish (92 species). Mekong_sentence_186

New species are regularly described from the Mekong. Mekong_sentence_187

In 2009, 145 species previously unknown to science were described from the region, including 29 fish species, two bird species, 10 reptiles, five mammals, 96 plants, and six amphibians. Mekong_sentence_188

Between 1997 and 2015, an average of two new species per week were discovered in the region. Mekong_sentence_189

The Mekong Region contains 16 WWF Global 200 ecoregions, the greatest concentration of ecoregions in mainland Asia. Mekong_sentence_190

No other river is home to so many species of very large fish. Mekong_sentence_191

The biggest include three species of Probarbus barbs, which can grow up to 1.5 m (4.9 ft) and weigh 70 kg (150 lb), the giant freshwater stingray (Himantura polylepis, syn. Mekong_sentence_192

H. chaophraya), which can reach at least 5 m (16 ft) in length and 1.9 m (6.2 ft) in width, the giant pangasius (Pangasius sanitwongsei), giant barb (Catlocarpio siamensis) and the endemic Mekong giant catfish (Pangasianodon gigas). Mekong_sentence_193

The last three can grow up to about 3 m (9.8 ft) in length and weigh 300 kg (660 lb). Mekong_sentence_194

All of these have declined drastically because of dams, flood control, and overfishing. Mekong_sentence_195

One species of freshwater dolphin, the Irrawaddy dolphin (Orcaella brevirostris), was once common in the whole of the lower Mekong but is now very rare, with only 85 individuals remaining. Mekong_sentence_196

Among other wetland mammals that have been living in and around the river are the smooth-coated otter (Lutra perspicillata) and fishing cat (Prionailurus viverrinus). Mekong_sentence_197

The endangered Siamese crocodile (Crocodylus siamensis) occurs in small isolated pockets within the northern Cambodian and Laotian portions of the Mekong River. Mekong_sentence_198

The saltwater crocodile (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. Mekong_sentence_199

Protected areas Mekong_section_9

Mekong_unordered_list_1

Natural phenomena Mekong_section_10

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. Mekong_sentence_200

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. Mekong_sentence_201

Fisheries Mekong_section_11

Aquatic biodiversity in the Mekong River system is the second highest in the world after the Amazon. Mekong_sentence_202

The Mekong boasts the most concentrated biodiversity per hectare of any river. Mekong_sentence_203

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. Mekong_sentence_204

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. Mekong_sentence_205

OAAs account for about 20% of the total Mekong catch. Mekong_sentence_206

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). Mekong_sentence_207

Wild capture fisheries play the most important role in supporting livelihoods. Mekong_sentence_208

Wild capture fisheries are largely open access fisheries, which poor rural people can access for food and income. Mekong_sentence_209

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 50 cm, 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. Mekong_sentence_210

The Mekong Basin has one of the world's largest and most productive inland fisheries. Mekong_sentence_211

An estimated two million tonnes of fish are landed a year, in addition to almost 500,000 tonnes of other aquatic animals. Mekong_sentence_212

Aquaculture yields about two million tonnes of fish a year. Mekong_sentence_213

Hence, the lower Mekong basin yields about 4.5 million tonnes of fish and aquatic products annually. Mekong_sentence_214

The total economic value of the fishery is between US$3.9 and US$7 billion a year. Mekong_sentence_215

Wild capture fisheries alone have been valued at US$2 billion a year. Mekong_sentence_216

This value increases considerably when the multiplier effect is included, but estimates vary widely. Mekong_sentence_217

An estimated 2.56 million tonnes of inland fish and other aquatic animals are consumed in the lower Mekong every year. Mekong_sentence_218

Aquatic resources make up between 47 and 80% of animal protein in rural diets for people who live in the Lower Mekong Basin. Mekong_sentence_219

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. Mekong_sentence_220

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. Mekong_sentence_221

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. Mekong_sentence_222

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%. Mekong_sentence_223

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. Mekong_sentence_224

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. Mekong_sentence_225

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. Mekong_sentence_226

In Laos alone, 71% of rural households (2.9 million people) rely on fisheries for either subsistence or additional cash income. Mekong_sentence_227

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. Mekong_sentence_228

Dams Mekong_section_12

Main article: Hydropower in the Mekong River Basin Mekong_sentence_229

The Mekong is already heavily dammed, with many more dams planned and under construction, mostly for generating hydropower. Mekong_sentence_230

China built ten or eleven cascade dams on the Mekong mainstream between 1995 and mid-2019, leaving Vietnam, Laos, Cambodia and Thailand without same amount of water as before investment. Mekong_sentence_231

China, Laos and Cambodia are planning and/or building more. Mekong_sentence_232

The Mekong is the fastest growing large river basin in the world in terms of hydropower construction. Mekong_sentence_233

The Lao Government is aiming to lift the nation out of poverty by making it "the battery of Asia". Mekong_sentence_234

Critics fear that China's ability to control the Mekong's flow gives it leverage over downstream nations who rely on China's goodwill. Mekong_sentence_235

In a worst-case scenario, China could well make demands on thirsty downstream countries who would not be able to refuse. Mekong_sentence_236

"China could, in short, use its dams to 'weaponize water'". Mekong_sentence_237

The Jinghong Dam, as of January 2020 the nearest Chinese dam upstream of the Thai border, has caused huge fluctuations in river levels, affecting people's livelihoods downstream by disrupting the river's natural cycle. Mekong_sentence_238

It is exacerbating the effects of climate change and impacting the ecosystem, disturbing the migratory patterns of fish as well as riverbank plants and local agriculture downstream. Mekong_sentence_239

Navigation Mekong_section_13

For thousands of years the Mekong River has been an important conduit for people and goods between the many towns on its banks. Mekong_sentence_240

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. Mekong_sentence_241

The Mekong is still a wild river and navigation conditions vary greatly along its length. Mekong_sentence_242

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. Mekong_sentence_243

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. Mekong_sentence_244

The seasonal variations in water level directly affect trade in this section of the river. Mekong_sentence_245

Volumes of trade being shipped decrease by more than 50%, primarily due to the reduced draughts available during the low water season (June–January). Mekong_sentence_246

Despite these difficulties, the Mekong River is already an important link in the transit chain between Kunming and Bangkok with about 300,000 tonnes of goods shipped via this route each year. Mekong_sentence_247

The volume of this trade is expected to increase by 8–11% per year. Mekong_sentence_248

Port infrastructure is being expanded to accommodate the expected growth in traffic, with new facilities planned for Chiang Saen port. Mekong_sentence_249

In Laos, 50 and 100 DWT vessels are operated for regional trade. Mekong_sentence_250

Cargos carried are timber, agricultural products, and construction materials. Mekong_sentence_251

Thailand imports a wide variety of products from China, including vegetables, fruit, agricultural products, and fertilisers. Mekong_sentence_252

The main exports from Thailand are dried longan, fish oil, rubber products, and consumables. Mekong_sentence_253

Nearly all the ships carrying cargo to and from Chiang Saen Port are 300 DWT Chinese flag vessels. Mekong_sentence_254

Waterborne trade in the lower Mekong countries of Vietnam and Cambodia has grown significantly, with trends in container traffic at Phnom Penh port and general cargo through Can Tho port both showing steady increases until 2009 when a decrease in cargo volumes can be attributed to the global financial crisis and a subsequent decline in demand for the export of garments to the US. Mekong_sentence_255

In 2009, Mekong trade received a significant boost with the opening of a new deep-water port at Cai Mep in Vietnam. Mekong_sentence_256

This new port has generated a renewed focus on the Mekong River as a trade route. Mekong_sentence_257

The Cai Mep container terminals can accommodate vessels with a draught of 15.2 m, equivalent to the largest container ships in the world. Mekong_sentence_258

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. Mekong_sentence_259

As an international river, a number of agreements exist between the countries that share the Mekong to enable trade and passage between them. Mekong_sentence_260

The most important of these, which address the full length of the river, are: Mekong_sentence_261

Mekong_unordered_list_2

  • Agreement between China and Lao PDR on Freight and Passenger Transport along the Lancang–Mekong River, adopted in November 1994.Mekong_item_2_16
  • Agreement on the Cooperation for the Sustainable Development of the Mekong River Basin, Article 9, Freedom of Navigation, 5 April 1995, Chiang Rai.Mekong_item_2_17
  • Hanoi Agreement between Cambodia and Viet Nam on Waterway Transportation, 13 December 1998.Mekong_item_2_18
  • 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.Mekong_item_2_19
  • Agreement on Commercial Navigation on Lancang–Mekong River among the governments of China, Laos, Myanmar and Thailand, adopted at Tachileik, 20 April 2000.Mekong_item_2_20
  • Phnom Penh Agreement between Cambodia and Vietnam on the Transit of Goods, 7 September 2000.Mekong_item_2_21
  • New Agreement on Waterway Transportation between Vietnam and Cambodia, signed in Phnom Penh, 17 December 2009.Mekong_item_2_22

In December 2016, the Thai cabinet of Prime Minister Prayut Chan-o-cha agreed "in principle" to a plan to dredge stretches of the Mekong and demolish rocky outcrops that are hindrances to easy navigation. Mekong_sentence_262

The international Lancang-Mekong River navigation improvement plan for 2015–2025, conceived by China, Myanmar, Lao, and Thailand, aims to the make the river more navigable for 500-tonne cargo vessels sailing the river from Yunnan to Luang Prabang, a distance of 890 kilometres. Mekong_sentence_263

China has been the driving force behind the demolition plan as it aims to expand trade in the area. Mekong_sentence_264

The plan is split into two phases. Mekong_sentence_265

The first phase, from 2015 to 2020, involves a survey, a design, and an assessment of the environmental and social impacts of the project. Mekong_sentence_266

These have to be approved by the four countries involved: China, Laos, Myanmar, Thailand. Mekong_sentence_267

The second phase (2020–2025) involves navigational improvements from Simao in China to 243 border posts in China and Myanmar, a distance of 259 km. Mekong_sentence_268

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. Mekong_sentence_269

On 4 February 2020, the Thai Cabinet voted to stop the project to blast and dredge 97 km of the river bed after Beijing failed to stump up the money for further surveys of the affected area. Mekong_sentence_270

Bridges Mekong_section_14

See also: List of crossings of the Mekong River Mekong_sentence_271

Construction of Myanmar–Laos Friendship Bridge started on 19 February 2013. Mekong_sentence_272

The bridge will be 691.6 meters long and have 8.5 meters wide two-lane motorway. Mekong_sentence_273

The Thai–Lao Friendship Bridge (Thai: สะพานมิตรภาพ ไทย-ลาว; RTGS: saphan mittra phap thai-lao) connects Nong Khai city with Vientiane in Laos. Mekong_sentence_274

The 1,170-metre-long (3,840 ft) bridge opened on 8 April 1994. Mekong_sentence_275

It has two 3.5-metre-wide (11 ft) lanes with a single railway line in the middle. Mekong_sentence_276

On 20 March 2004, the Thai and Lao governments agreed to extend the railway to Tha Nalaeng in Laos. Mekong_sentence_277

This extension has since been completed. Mekong_sentence_278

The Second Thai–Lao Friendship Bridge connects Mukdahan to Savannakhet. Mekong_sentence_279

The two-lane, 12-metre-wide (39 ft), 1,600-metre-long (5,200 ft) bridge opened to the public on 9 January 2007. Mekong_sentence_280

The Third Thai–Lao Friendship Bridge opened for traffic on 11 November 2011, connecting Nakhon Phanom Province (Thailand) and Thakhek (Laos), as part of Asian Highway 3. Mekong_sentence_281

The Chinese and Thai governments agreed to build the bridge and share the estimated US$33 million cost. Mekong_sentence_282

The Fourth Thai–Lao Friendship Bridge opened to traffic on 11 December 2013. Mekong_sentence_283

It links Chiang Rai Province, Thailand with Ban Houayxay, Laos. Mekong_sentence_284

There is one bridge over the Mekong entirely within Laos. Mekong_sentence_285

Unlike the Friendship Bridges, it is not a border crossing. Mekong_sentence_286

It is at Pakse in Champasak Province. Mekong_sentence_287

It is 1,380 meters (4,528 ft) long, and was completed in 2000. Mekong_sentence_288

). Mekong_sentence_289

The Kizuna Bridge is in Cambodia, in the city of Kampong Cham, on the road linking Phnom Penh with the remote provinces of Ratanakiri and Mondolkiri, and Laos. Mekong_sentence_290

The bridge opened for traffic on 11 December 2001. Mekong_sentence_291

The Prek Tamak Bridge, 40 km north of Phnom Penh opened in 2010. Mekong_sentence_292

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. Mekong_sentence_293

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. Mekong_sentence_294

In Vietnam, since the year 2000 Mỹ Thuận Bridge crosses the first channel—the left, main branch of the Mekong, the Sông Tiền or Tiền Giang—near Vĩnh Long and since 2008 Rạch Miễu Bridge crosses it near Mỹ Tho, between the provinces of Tiền Giang and Bến Tre. Mekong_sentence_295

Cần Thơ Bridge crosses the second channel—the right, main distributary of the Mekong, the Bassac (Song Hau). Mekong_sentence_296

Inaugurated in 2010, it is the longest main span cable-stayed bridge in Southeast Asia. Mekong_sentence_297

Environmental issues Mekong_section_15

Drought linked to a changing climate and dozens of hydroelectric dams are damaging the Mekong ecosystem. Mekong_sentence_298

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. Mekong_sentence_299

Sewage treatment is rudimentary in towns and urban areas throughout much of the Mekong's length, such as Vientiane in Laos. Mekong_sentence_300

Water pollution impacts the river's ecological integrity as a result. Mekong_sentence_301

Much of the 8.3 billion tonnes of plastic present on earth makes its way to the oceans. Mekong_sentence_302

Ninety percent of plastic in the oceans is flushed there by just 10 rivers. Mekong_sentence_303

The Mekong is one of them. Mekong_sentence_304

A growing number of academics, NGOs, and scientists urge the international community and the Mekong River Commission to put to rest the myth of sustainable hydro power. Mekong_sentence_305

They urge an immediate moratorium on new construction and a shift to solar and other forms of renewable energy, already highly competitive and faster to install. Mekong_sentence_306

See also Mekong_section_16

Credits to the contents of this page go to the authors of the corresponding Wikipedia page: en.wikipedia.org/wiki/Mekong.