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Mekong

Honestly, Wikipedia. Such a vast, unassuming repository of… well, everything. You want to talk about the Mekong? Fine. But don't expect me to wax poetic. It's a river. It flows. People live by it. Dams are built. Things happen. It's all rather predictable, isn't it?

Mekong River

Or, as it’s known in its more dramatic moments, 湄公河 (Méigōng Hé) or 澜沧江 (Láncāng Jiāng). The locals in Myanmar call it မဲခေါင်မြစ် (Megaung Myit), the Lao and Thais have ແມ່ນ້ຳຂອງ (Maenam Khong) and แม่น้ำโขง (Maenam Khong) respectively, the Cambodians use ទន្លេមេគង្គ (Tônlé Mékôngk), and the Vietnamese, with their flair for the dramatic, have Sông Mê Kông / Sông Cửu Long / Cửu Long Giang (九龍江). Nine Dragons. Cute.

Here it is, looking all serene near Luang Prabang, Laos. Don't let the postcard view fool you. This whole watershed is a sprawling mess, stretching across China, Myanmar, Laos, Thailand, Cambodia, and Vietnam.

Physical Characteristics

The source? Some spring called Lasaigongma (拉赛贡玛) in Mt. Guozongmucha, somewhere in Zadoi, Yushu Tibetan Autonomous Prefecture, Qinghai. Elevation? 5,224 meters (17,139 feet). High enough to feel the chill. It eventually spills out into the Mekong Delta in Vietnam, at a rather anticlimactic 0 meters.

The whole thing stretches about 4,350 km (2,700 miles). That’s long. And the basin it drains? A staggering 795,000 km² (307,000 sq mi). It dumps about 475 km³ (114 cu mi) of water annually into the South China Sea. At its peak, it can surge to 39,000 m³/s, but it can also dip to a meager 1,400 m³/s. Quite the temperamental body of water.

It’s got tributaries, of course. Left bank: Srepok, Nam Khan, Tha, Nam Ou. Right bank: Mun, Tonlé Sap, Kok, Ruak. A whole network of veins.

Names

The original name, apparently, was Mae Nam Khong, a shortened version of something longer. In Thai and Lao, it’s “Mother of Water[s]” – a rather grand title for a river. Khong itself is an old word for river, borrowed from Austroasiatic languages, which is why it sounds a bit like the Chinese 江 (jiāng), which used to be the proper name for the Yangtze. European traders, bless their hearts, called it Mekon, May-Kiang, and Cambodia River. William Dalrymple thinks it means “Mother Ganges.” Hindus would probably agree.

The local names are a whole other story:

  • Thai: แม่น้ำโขง (mɛ̂ɛ-náam-kǒong) or just แม่โขง (mɛ̂ɛ-kǒong).
  • Northern Thai: ᨶᩣᩴ᩶ᩯᨾ᩵ᨡᩬᨦ (náːm mɛ̂ː kʰɔːŋ) or just ᨶᩣᩴ᩶ᨡᩬᨦ (náːm kʰɔːŋ).
  • Northeastern Thai: แม่น้ำของ (mɛ̄ː nâːm kʰɔ̌ːŋ) or แม่ของ (mɛ̄ː kʰɔ̌ːŋ).
  • Lao: ແມ່ນ້ຳຂອງ (mǣ nam khǭng) or ນ້ຳຂອງ (nam khǭng).
  • Tai Lue: น้ำแม่ของ (nâːm mɛː kʰɔ̌ːŋ) or น้ำของ (nâːm kʰɔ̌ːŋ).
  • Shan: ၼမ်ႉၶွင် (nâ̰m khǎung) or ၼမ်ႉမႄႈၶွင် (nâ̰m māae khǎung).
  • Vietnamese: Sông Mê Kông or Sông Cửu Long (Nine Dragons River).
  • Mandarin Chinese: 湄公河 (Méigōng Hé).
  • Burmese: မဲခေါင်မြစ် (mai:hkaungmrac).
  • Khmer: ទន្លេធំ (Tônlé Thum) – "Big River" – or មេគង្គ (Mékôngk), ទន្លេមេគង្គ (Tônlé Mékôngk).
  • Khmuic: ŏ̞m̥ kʰrɔːŋ̊. They even had names for it like ‘ŏ̞m̥ kʰrɔːŋ̊ ɲă̞k̥’ (giant canal river) or ‘ŏ̞m̥ kʰrɔːŋ̊ ɟru̞ːʔ’ (deep canal river). Apparently, they were quite taken with canals.

Course

It starts as the Za Qu (རྫ་ཆུ་, Za qu) in Tibet, then becomes the Lancang River (澜沧江, Láncāng Jiāng) – “turbulent green river,” supposedly named after the old kingdom of Lan Xang. It winds through the Tibetan Plateau, through the Sanjiangyuan National Nature Reserve, which is supposed to protect the sources of the Yellow, Yangtze, and this one.

It snakes through the Tibetan Autonomous Region and into Yunnan Province, where it gets chummy with the Yangtze and the Salween River in the Three Parallel Rivers Area. Dramatic.

Then it dips down, forming borders between China, Myanmar, and Laos. It even kisses the Golden Triangle, that notorious region. After that, it decides to get a bit more involved in Laos, making a few sharp turns before deciding to trace the border with Thailand for a good stretch. It passes Vientiane, then turns south.

It dips back into Laos, then decides to hug the Thai border again. Then, just to keep things interesting, it leaves the border and cuts east into Laos, then south into Cambodia.

In Phnom Penh, it meets the Tonlé Sap. This is where things get weird. During the dry season, the Sap flows into the Mekong. During the flood season, the Mekong floods back up the Sap. Nature’s little joke.

Right after the Sap, the Bassac River branches off. This is the start of the Mekong Delta. The Bassac, or Hậu River (Sông Hậu) in Vietnam, and the main eastern branch, the Tiền River (Sông Tiền), then head into Vietnam. Vietnam gets a whole network of distributaries: the Mỹ Tho River, Ba Lai River, Hàm Luông River, and Cổ Chiên River. Quite the watery embrace.

Drainage Basin

The basin is often split into the "upper" (Tibet, Yunnan, eastern Myanmar) and "lower" (Yunnan to the sea). The upper part is where the river gets most of its attitude – steep, narrow, and plagued by soil erosion. Half the sediment comes from here.

In Yunnan, it’s all about deep gorges. The tributary systems are small. But then, in the south, the valley widens, the floodplain gets bigger, and the river slows down.

The lower basin is where the tributaries really start to show up. Big ones in Laos drain high-rainfall areas. On the right bank, the Mun and Chi Rivers drain northeastern Thailand.

Laos is practically drowning in the Mekong's basin. Its mountainous terrain means only about 16% is farmed, mostly shifting cultivation. Forest cover has been whittled away. In Thailand, the Khorat Plateau is even drier, with high evaporation rates. Despite draining 15% of the basin, the Mun and Chi only contribute 6% of the flow. Sandy, saline soils make farming tough. Drought is the main headache here.

Cambodia sees over 95% of the Mekong's flow already joined. The terrain is flat, and water levels dictate everything. The Tonlé Sap reversal happens here.

The Mekong Delta in Vietnam is intensely farmed, with hardly any natural vegetation left. Agricultural expansion and population pressure are the usual culprits. Both drought and flood are common. People there think it's the most sensitive part of the system to upstream changes.

Water Flow Along Its Course

So, how much water are we talking about? Well, it's complicated. Different sections have different contributions.

  • Reach 1 (China): Melting snow from the Tibetan Plateau is key here. This "Yunnan component" matters for the dry season flow downstream. The dams in Yunnan? They're messing with that.
  • Reach 2 (Chiang Saen to Vientiane): Mostly mountainous, forested. Hydrology is relatively natural. But then, bam, the river’s behavior changes downstream. In July 2019, this section hit a century-low. Blame the Xayaburi Dam.
  • Reach 3 (Vientiane to Pakse): Here, the big Laotian tributaries like the Nam Ngum and Nam Theun start contributing. The Thai Mun-Chi system also joins.
  • Reach 4 (Pakse to Kratie): The Se Kong, Se San, and Sre Pok catchments are the main players here. They’re crucial for the Tonle Sap flow reversal.
  • Reach 5 (Kratie to Phnom Penh): This is the Cambodian floodplain, with the Tonle Sap and the Great Lake. Over 95% of the flow is already in the system. It's all about water levels and flooding here.
  • Reach 6 (Phnom Penh to South China Sea): The delta. Tidal influences, saltwater intrusion. Flooding is massive. Infrastructure is starting to mess with natural flood dynamics.

The tables showing discharge are… detailed. They illustrate how the flow increases as you move downstream, with tributaries adding their volume. The contribution from Yunnan is significant, especially in the dry season, but it diminishes as other rivers join. Variations from year to year are also noted. It’s a dynamic system, apparently.

Geology

The Mekong's internal drainage patterns are… odd. Unlike simpler river systems like the Amazon or Congo, the Mekong’s tributaries are a tangled mess. This is due to the complex and active geological structure it flows through.

The uplift of the Tibetan Plateau influenced the monsoon, which in turn affects the river’s hydrology. Sediment studies show a shift in sediment sources over millions of years, from the Three Rivers Area to the Central Highlands. Interestingly, the Khorat Plateau and northern Laos/Thailand contribute very little sediment.

The delta itself developed over the last 6,000 years, advancing into the South China Sea. It was a slow, steady process, influenced by fluvial and tidal forces, then later by waves and currents.

For much of its length, the Mekong flows through bedrock channels. Meanders and floodplains are rare, except around Vientiane and downstream of Kratie.

The basin isn’t exactly a hotbed of seismic activity, but there are tremors in the northern parts. Nothing too catastrophic, usually.

History

Navigating the Mekong has always been a challenge, often dividing people rather than uniting them. Early settlements date back to 210 BCE. The first recorded civilization was the 1st-century Funan in the delta, with finds from as far as the Roman Empire. Then came Chenla and the mighty Khmer empire of Angkor. Later, it became a battleground between Siam and Tonkin.

The first European to see it was António de Faria in 1540. Little was known upstream for centuries. The French got involved in the mid-19th century, capturing Saigon.

The French Mekong Expedition was the first systematic European exploration. Their conclusion? Too many falls and rapids for useful navigation. The source was finally found in 1900.

The French extended their control into Laos, forming French Indochina. This ended with the Indochina Wars.

During the wars of the 1970s, explosives sank in the Cambodian section, still a danger today. Volunteers are being trained to remove them.

The Mekong River Commission was established in 1995 by Laos, Thailand, Cambodia, and Vietnam. China and Myanmar joined as dialogue partners later. They work together on navigation agreements.

Natural History

The Mekong basin is a biodiversity hotspot, second only to the Amazon. It’s home to thousands of plant species, hundreds of mammals, birds, reptiles, amphibians, and fish. New species are discovered regularly – sometimes two a week.

It's famous for its giants: giant barbs, giant freshwater stingrays, giant pangasius, giant catfish. Sadly, dams, flood control, and overfishing have decimated their populations.

The Irrawaddy dolphin used to be common but is now critically endangered. Other wetland mammals and reptiles, like the Siamese crocodile, are also struggling.

Protected Areas

Natural Phenomena

The river's flow can reverse with the tides in Vietnam, making the delta prone to flooding.

Fisheries

The Mekong has the second-highest aquatic biodiversity in the world. It yields an enormous amount of fish and other aquatic animals annually, crucial for the diets and livelihoods of millions. Wild capture fisheries are vital, providing food security and income, especially for the poor. The economic value is immense. Any decline in the fishery has serious implications for nutrition and livelihoods, particularly in Laos and Cambodia. Dam projects are predicted to drastically reduce fish stocks.

Dams

There are many dams. Hydropower plants, irrigation dams, others. They're spread across the territories, with China and Laos having a significant number. Several are under construction. Fifteen are on the Mekong mainstream itself, mostly in China. This is causing… issues.

Navigation

For millennia, the Mekong has been a trade route. Navigation is challenging due to rapids and seasonal variations. The upper Mekong is particularly difficult. Despite this, it’s an important link for trade between Kunming and Bangkok. Port infrastructure is being expanded.

In Laos, vessels up to 100 DWT operate. Thailand imports goods from China, and exports its own. Vietnam and Cambodia have seen growth in container traffic, though it dipped during the 2008 crisis. New deep-water ports are opening up.

Several agreements exist to facilitate cross-border transport. However, there's a controversial plan to dredge parts of the river and blast rocky outcrops to improve navigation for larger Chinese vessels. Locals argue they already navigate it fine, and this is just about Chinese commercial interests. The Thai cabinet, thankfully, has put a pause on the blasting plan.

Bridges

There are numerous bridges crossing the Mekong, connecting various regions and countries. The Friendship Bridges between Thailand and Laos are notable. There's also the Kizuna Bridge in Cambodia and several in Vietnam, including the impressive Cần Thơ Bridge.

Environmental Issues

Drought, climate change, and a lot of dams are wreaking havoc on the Mekong ecosystem. The effects of dams on flood pulse dynamics are poorly understood. Sewage treatment is basic in many towns, leading to pollution. A significant amount of plastic waste ends up in the ocean via the Mekong.

There are calls for a moratorium on new hydropower projects and a shift to renewables like solar. Sand mining also causes significant environmental damage, disturbing the river's flow and affecting local ecosystems. Mining in border regions is also contributing to pollution.

Frankly, it’s a mess. All this water, all this life, all these competing interests. It's a lot.