Why China Built the Three Gorges Dam and Why It Remains Controversial

Why China Built the Three Gorges Dam and Why It Remains Controversial

The Three Gorges Dam on the Yangtze River is the world's largest power station by installed capacity (22,500 MW) and one of the most controversial infrastructure projects in history. It displaced 1.4 million people, submerged entire cities, and altered the ecosystem of China's longest river. Yet it also generates 100 TWh of clean electricity annually and has prevented catastrophic flooding downstream. The dam embodies the tension between development and environmental protection that defines modern China.

The Dam

• Location: Yichang, Hubei Province, Yangtze River
• Height: 181 meters
• Length: 2,335 meters
• Reservoir length: 600 km
• Installed capacity: 22,500 MW (largest in the world)
• Annual generation: ~100 TWh (enough for 30+ million households)
• Cost: $31 billion (official); estimates up to $50 billion including relocation
• Construction: 1994-2006 (12 years, completed ahead of schedule)
• Ships can pass: Via 5-stage lock system and ship elevator (5,000-tonne capacity)

Why It Was Built

1. Flood control (primary justification):

• The Yangtze has killed over 1 million people in floods over the past 2,000 years
• 1931 flood: 145,000-4 million deaths (various estimates)
• 1954 flood: 30,000+ deaths, 18 million people affected
• 1998 flood: 4,000+ deaths, $36 billion in damage
• The dam protects 15 million people and 1.5 million hectares of farmland downstream
• Since completion: No catastrophic downstream floods (previously occurred every decade)

2. Power generation:

• 22,500 MW capacity = 100 TWh/year
• Replaces ~30 million tonnes of coal per year (CO2 reduction)
• Power is transmitted to eastern China (Shanghai, Guangdong) via HVDC lines
• China's push for clean energy: Reduces coal dependency

3. Navigation:

• The dam allows 10,000-tonne ships to reach Chongqing (previously limited to 1,500 tonnes)
• Shipping costs reduced by 35% on the Yangtze
• "Golden Waterway" strategy: Turn the Yangtze into a major inland shipping corridor
• 600 km of reservoir enables year-round navigation (previously seasonal)

The Controversies

1. Displacement (largest forced migration in peacetime):

• 1.4 million people relocated
• 13 cities, 140 towns, 1,350 villages submerged
• Some relocated communities experienced poverty and social dislocation
• Compensation was often insufficient (farmers received less land, city dwellers received inferior housing)
• Historic sites submerged: 1,300+ archaeological sites lost

2. Environmental impact:

• Landslides: Reservoir water destabilizes riverbanks (documented increase in landslides)
• Sediment trapping: Dam traps silt that would normally nourish downstream ecosystems
• Downstream erosion: Clear water below dam erodes riverbed (threatens levees)
• Biodiversity: Yangtze river dolphin (baiji) declared extinct (2006); sturgeon critically endangered
• Water quality: Reservoir has experienced algal blooms and pollution concentration
• Seismic risk: 1+ million micro-earthquakes recorded since reservoir filling (water weight triggers faults)

3. Geological concerns:

• Reservoir-induced seismicity (earthquakes triggered by water weight)
• 1,000+ micro-earthquakes since filling began
• No major damaging earthquakes (yet), but long-term risk remains
• Landslide risks along 600 km of reservoir shoreline

4. Downstream effects:

• Reduced sediment flow has affected the Yangtze delta (erosion, saltwater intrusion)
• East China Sea coast receding due to lack of sediment replenishment
• Poyang Lake (China's largest freshwater lake) has shrunk dramatically
• Ecosystem changes downstream of the dam

The Benefits

• 100 TWh/year of clean electricity (eliminates 30M tonnes CO2)
• Flood protection for 15 million people downstream (no catastrophic floods since completion)
• Improved navigation: 10,000-tonne ships reach Chongqing, 35% cost reduction
• Economic development: Clean power supports eastern China's manufacturing economy
• Drought resistance: Reservoir can release water during dry seasons to maintain downstream flow

The Verdict

The Three Gorges Dam is simultaneously one of the greatest engineering achievements and one of the most environmentally disruptive projects in human history. It provides clean energy, flood control, and navigation improvements that benefit tens of millions. It also displaced 1.4 million people, contributed to species extinction, and altered one of the world's great rivers forever. Whether you view it as a triumph of development or an environmental catastrophe depends on whether you prioritize human welfare or ecological preservation — and how you weigh short-term benefits against long-term costs. The dam exists; the debate continues.

The Takeaway

The Three Gorges Dam is the world's largest power station and a monument to China's determination to control nature. It generates enough clean electricity for 30 million households, prevents catastrophic flooding, and enables ocean-going ships to reach 2,000 km inland. It also displaced 1.4 million people, likely contributed to the extinction of the Yangtze river dolphin, and permanently altered one of Earth's great river ecosystems. No infrastructure project in history has simultaneously achieved so much and cost so much. The dam is a reminder that every engineering decision involves trade-offs — and that the biggest projects have the biggest consequences, both good and bad.