Visualizing Environmental Science

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b. The finless porpoise has been threatened

by the construction of the Three Gorges Dam.

a. The Three Gorges Dam
spans the Yangtze River in
China’s Hubei Province.

NG Maps

Global

Locator

HUBEI PROV., CHINA

SICHUAN PROV., CHINA

Jing Zhou

Three

Gorges Dam

Yichang

FengjieWushan

Wanxian

Fengdu

Wu River

Lesser Three Gorges Shennong Stream

To Shanghai

Wuhan

Hubei Province

Sichuan Province

Chongqing

Jing Zhou

Three

Fengjie Gorges Dam

Chongqing

http://www.chinatouristmaps.com/assets/images/travelmap/Sketch-Map-of-The-Three-Gorges.jpg

✓✓THE PLANNER

China’s Three Gorges Dam

The Three Gorges Dam on China’s Yangtze River is a testament
to human alteration of nature on a massive scale (see map).
As the world’s largest dam on the world’s longest river, it is
an engineering wonder that provides huge benefits, but its
environmental impacts are also likely to be vast and profound.
Launching operations in 2008 after 14 years of construction,
the Three Gorges Dam project was initiated to control the often
devastating flooding that occurred during China’s rainy seasons
and to make water more available to drought-prone areas during
dry seasons. The dam has also improved navigation, enhancing
shipping through a system of locks, and generates clean
electricity: Its 26 hydropowered generators can produce nearly
85 billion kilowatt-hours each day, an equivalent of the electricity
produced by burning 50 million tons of coal.
With the dam height of 185 m (607 ft), the Three Gorges
project has raised water levels from a low-water mark of 62 m
(203 ft) to a maximum height of 175 m (574 ft) in the reservoir
behind the dam (Figure a). The rising waters flooded entire
communities and required nearly 2 million people to relocate.
This transformation in the river ecosystem also fragmented
habitat, turning dozens of hilltops into islands.
Many fish species in the Yangtze Basin are now declining.
Spawning conditions have been altered for many, including
valuable carp species, and migratory routes have been blocked
for others, including sturgeon. Rare freshwater mammals—
including the river dolphin (baiji) and finless porpoise
(jiangzhu)—appear to be in serious danger (Figure b).

Other large-scale environmental impacts of the massive

Three Gorges project include the unknown effects of silt

buildup behind the dam, apparent declines in water quality as

nutrient levels rise in the slowly moving water, potential bank

destabilization and erosion that have increased the risk of

landslides, and enormous water pollution issues associated with

industry and shipping.

The Chinese Academy of Sciences is monitoring these

environmental issues. Its findings have generated a government

plan to be implemented between 2010 and 2020, to address

these varied and serious ecological impacts of the Three Gorges

Dam.

CASE STUDY