Landslide Disaster Mitigation in Three Gorges Reservoir






Preface

The Yangtze River is the largest river in China, and the Three Gorges section is

one of the most beautiful parts of the river. In order to harness the hydropower of

the Yangtze River, a dream was envisioned by Mr. Sun Yat-Sen, the first president

of China. In 1918, Sun Yat-Sen suggested in his book, Strategy for State, “a dam

should be set here to let ships go downstream and use the water resource as power”.

Through the efforts of the Chinese people the dream came true after 100 years.

Begun in 2004, the Three Gorges dam construction was completed in 2006, and

the dam operation will become fully functional in 2009, when the reservoir water

level will reach the maximum height of 175 m. Before the dam construction, the

water level at the Three Gorges dam site was 90 m. An increase of 85 m of slowly

rising water in a reservoir with a length of about 660 km from the dam to its terminus

at Chongqing City has greatly impacted the environment. The impact on the

geo-environment, especially the instability phenomenon and landslides, was given

great attention, because landslides not only affect the people living on the bank

slopes but also affect navigation and shipping on the river. In addition, the sliding

masses moving into the reservoir will have negative effects on the lifetime of the

reservoir itself. Because of the importance of this consideration, bank slope stability

and landslide problems have been, and will continue to be studied systematically.

The studies can be divided into two periods seperating in June 2003, when the first

reservoir impoundment was conducted for partial operation. To summarize, the studies

before the impoundment were concentrated on landslide site identification, and

instability evaluation of existing landslides; while in the period after the impoundment,

the studies shifted to landslide monitoring and prediction of landslides caused

by water-level changes during the reservoir operation. The purposes of the studies

for the two periods are the same, which is to acquire sufficient data and information

for landslide disaster mitigation.


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