Jinping-I Dam: The World's Tallest Dam

**Jinping-I Dam** on the Yalong River in Sichuan Province, China, is the **tallest dam in the world**, soaring **305 meters** from foundation to crest. This double-curvature arch dam harnesses the steep gradient of the Yalong River as it cuts through the Jinping Mountains, generating **3,600 MW** of hydroelectric power in one of China's most geologically challenging construction environments.

Introduction

Completed in 2014, Jinping-I is the flagship structure of a multi-dam cascade on the Yalong River, a major tributary of the Yangtze. The dam's extreme height and remote mountain location required innovative engineering solutions and over a decade of construction in terrain where access roads alone took years to build.

Engineering & Structure

• Type: Double-curvature arch dam
• Height: 305 meters (world's tallest)
• Crest Length: 568 meters
• Concrete Volume: 4.67 million m³

Jinping-I is a parabolic double-curvature arch dam that transfers the pressure of its reservoir into the solid gneiss rock of the canyon walls. At 305 meters, it surpasses the Nurek Dam in Tajikistan (300 meters) as the world's tallest dam. The crest spans 568 meters across the gorge, and the dam's thickness varies from 16 meters at the crest to 63 meters at the base.

Construction in the steep, earthquake-prone gorge presented extraordinary challenges. Engineers used a combination of cable cranes and belt conveyors to place 4.67 million cubic meters of concrete. Advanced temperature control systems prevented thermal cracking during curing, a critical concern in arch dams where structural integrity depends on the monolithic behavior of the concrete.

Geographic Setting

• River: Yalong River (Yangtze tributary)
• Location: Yanyuan and Muli counties, Sichuan, China
• Coordinates: 28.17°N, 101.63°E
• Elevation: Dam crest at ~1,885 m above sea level

The Yalong River descends from the eastern edge of the Tibetan Plateau through deep gorges in western Sichuan Province. At the Jinping-I dam site, the river passes through a dramatic U-shaped bend around the Jinping Mountains, dropping over 300 meters in elevation over a short distance — creating ideal conditions for hydroelectric development.

The surrounding terrain is extraordinarily rugged, with mountain peaks exceeding 4,000 meters and valley floors below 1,600 meters. The region is sparsely populated, home mainly to Tibetan and Yi ethnic minorities. The remote location made logistics a major challenge; constructing the access roads and tunnels to the dam site was itself a multi-year engineering project.

Hydroelectric Power

• Installed Capacity: 3,600 MW
• Annual Output: ~16.6 TWh
• Turbines: 6 × 600 MW Francis turbines

Jinping-I houses six 600 MW Francis turbines in an underground powerhouse excavated from the mountain rock. The dam's enormous head — the vertical distance between the reservoir surface and the turbines — provides exceptional energy per unit of water flow. Annual generation averages approximately 16.6 terawatt-hours, transmitted to Sichuan's grid and onward to eastern China.

The dam works in tandem with the downstream Jinping-II hydroelectric station, which exploits the river's U-shaped bend by diverting water through four headrace tunnels totaling 16.7 kilometers each — among the longest hydraulic tunnels in the world. Together, the two Jinping stations form a highly efficient cascade system.

Environmental & Social Impact

• People Relocated: ~7,500
• Seismic Risk: Monitored for reservoir-induced seismicity
• Ecological Concern: Yalong River fish species habitat disruption

The relatively sparse population in the Jinping gorge meant that only about 7,500 people required relocation, far fewer than China's lowland dam projects. However, the affected communities were predominantly ethnic minorities with deep cultural connections to the land, making resettlement socially sensitive despite the smaller numbers.

The dam blocks fish migration routes on the Yalong River, threatening several endemic species. The reservoir also submerged sections of the river's unique riparian ecosystems. Seismologists closely monitor the region for reservoir-induced seismicity, as the weight of the impounded water can trigger earthquakes in geologically stressed areas. Several minor tremors have been recorded since the reservoir began filling.

Key Facts

• At 305 meters, Jinping-I is the tallest dam in the world.
• It generates 3,600 MW from six underground Francis turbines.
• The dam is built in one of China's most remote and rugged mountain gorges.
• It works in tandem with Jinping-II, which uses 16.7 km headrace tunnels.
• Annual electricity output averages approximately 16.6 TWh.

Fun Facts

• The Jinping Mountains beneath which the tunnels were bored provide 2,400 meters of rock overburden, making them the deepest underground laboratories in the world — China built a dark matter research lab inside the tunnel complex.
• Access roads to the dam site had to be carved through mountains with gradients exceeding 70 degrees in places.
• The Yalong River's name derives from Tibetan and means "Yak River."

Final Thoughts

Jinping-I Dam represents the extreme frontier of dam engineering, achieving the world's greatest height in a remote and seismically active mountain environment. Its record-setting scale and the innovative Jinping-II tunnel system demonstrate the lengths to which engineers will go to harness the hydroelectric potential of high-altitude rivers.