Planned Dams (2020): 22

Population (2020): 77,700,493

Area in Square Kilometers: 781,643

Consumption (Cubic Km/Year): 10,260

Withdrawal (Cubic Km/Year): 29,560

Runoff(mm/Year): 650

Countries: Cambodia, China, Lao People's Democratic Republic, Mongolia, Myanmar, Thailand, Viet Nam

• The natural flow regime of the Mekong has changed- a result of the hydropower dams constructed on the mainstream in the Upper Mekong River Basin and on tributaries in the Lower Mekong River Basin

• Floodplains are being developed and flood protection and river training are being taken up at many locations. Industrial activities such as sediment extraction from river channels are increasing.

• The potential for water-related emergency situations is increasing, Natural disasters, such as flood and droughts, could become more frequent and severe in the future.

• Developments outside the water sector are impacting water related resources. These include the construction of (international) roads, railways and power transmission infrastructure, the development of non-irrigated agriculture and mining activities, as well as deforestation and urbanisation.

Key points:

• Covers about 795,000 km², making it one of the largest river basins in Asia

• The Mekong has a highly seasonal flow, with heavy monsoon floods and dry-season shortages

• Around 70 million people live in the basin, many relying directly on the river for food, water, and livelihoods

• Supports one of the most productive agricultural regions in the world; the Mekong Delta in Vietnam is often called the "rice bowl of Asia."

• Home to the largest inland fishery globally, providing up to 25% of the world’s freshwater catch.

• Extremely rich in wildlife, including endangered species such as the Irrawaddy dolphin and giant catfish.

• Increasingly developed for dams, especially in Laos and China, leading to major debates about sustainability, water sharing, and downstream impacts.

• Chinese “Lancang Cascade”: Mega-dams like Xiaowan and Nuozhadu provide huge storage and hydropower capacity. These regulate seasonal flows but also trap sediment and block fish migration.

• Laos Mainstream Projects: Notably Xayaburi Dam (financed with Thai support) and Don Sahong Dam (near the Cambodia border), controversial for fish migration and biodiversity impacts.

• Tributary Dams: Dozens in Laos and Cambodia, further fragmenting river systems.

• Irrigation Diversions: Thailand and Vietnam operate extensive irrigation and canal systems, altering flow regimes.

• Delta Infrastructure: Vietnam uses dikes, sluice gates, and canals to manage salinity and floods, but these are increasingly overwhelmed by upstream changes and climate-driven sea-level rise.

a) Flow Regulation & Water Security

• Upstream dams give China and Laos hydrological leverage, affecting downstream irrigation, flood protection, and ecosystems.

• Downstream states worry about unilateral dam operations with little data-sharing (China provides only limited seasonal data).

b) Fisheries & Livelihoods

• Cambodia faces collapse of Tonle Sap fisheries, directly tied to changes in flood pulse and connectivity — a huge livelihood and food security issue.

c) Climate Change as a “Threat Multiplier”

• Droughts and erratic rainfall (e.g., 2019 drought) are magnified by upstream regulation, heightening downstream suspicion that dams worsen natural variability.

d) Governance Gaps

• The Mekong River Commission (MRC) excludes China as a full member — Beijing only participates as a “dialogue partner.”

• China instead pushes the Lancang-Mekong Cooperation Mechanism (LMC), shifting influence away from the MRC. This fragmented governance raises risks of competing water management rules.

• Ancient Civilisations: The Mekong supported the Khmer Empire (9th–15th centuries), whose capital at Angkor relied on complex irrigation linked to Mekong tributaries.

• Cultural significance: For centuries, the river has been central to livelihoods, trade, and spiritual traditions across Laos, Cambodia, Thailand, and Vietnam.

Colonial & Early Modern Period

• 1866–1868: The French Mekong Expedition attempted to navigate the river for trade routes into China but found navigation blocked by rapids and waterfalls.

• French Indochina (19th–20th c.): France promoted the river as a transport route and resource base, beginning early basin-wide planning.

• 1947: The UN Economic Commission for Asia and the Far East (ECAFE) initiated studies for Mekong development, marking the first international push for coordinated use.

Cold War Era

• 1957: Establishment of the Mekong Committee (Cambodia, Laos, Thailand, South Vietnam) under UN auspices to promote joint development.

• 1960s–70s: U.S. involvement — the Mekong was seen as part of Cold War strategy. Plans for massive dam projects stalled due to the Vietnam War and regional instability.

• 1975: After the Vietnam War, regional cooperation collapsed; Cambodia’s Khmer Rouge government withdrew from Mekong development.

Renewed Regional Cooperation

• 1995: Creation of the Mekong River Commission (MRC) by Cambodia, Laos, Thailand, and Vietnam. Its goal: to coordinate sustainable development and manage shared resources.

• China and Myanmar: Not members of the MRC but became “dialogue partners.” China’s upstream dam building often strained relations with downstream states.

Hydropower & Modern Development

• Early 2000s: Rapid growth of dam construction, especially in China (Lancang cascade dams) and Laos (“Battery of Southeast Asia” vision).

• 2009: Laos proposed the controversial Xayaburi Dam, the first mainstream dam on the lower Mekong — sparking protests from Cambodia and Vietnam over fishery and sediment losses.

• 2010s: Further dams followed (e.g., Don Sahong, Pak Beng), intensifying ecological and geopolitical concerns.

Recent Challenges & Events

• 2016: Record droughts hit the basin, with criticism that Chinese dams worsened water shortages.

• 2020: Research showed that China’s upstream dams were holding back water during droughts, sparking tensions.

• 2021–Present: Climate change impacts, combined with upstream dam expansion, have worsened salinization in Vietnam’s Mekong Delta and declining fisheries in Cambodia’s Tonle Sap.