Rivers, Floods and |Management - Hard engineering - The river Yangtze Flashcards
Where is the Yangtze river located?
China
What is the problem?
China has a rainy season from June to August and this causes flooding. There are major cities and precious farmland located near the river that are damaged.
How many major floods have there been over the last 100 years?
5
What were the rough effects of the 1954 flood?
190 square km of land covered. 33,000 people killed. 18 million left homeless.
What were the rough effects of the 1998 flood? After some defenses were put in place?
3000 people killed. 14 million homeless.
What do most of the defenses consist of?
Dams and Levees.
Talk about the Three Gorges Dam?
The largest of the dams on the Yangtze river. Built in 1994. 101m high.
A reservoir is building up behind the dam, this takes years. The reservoir can hold 22 square km of water and holds flood water so it can be released slowly to avoid flooding.
There are 26 inbuilt turbines making it the largest source of hydroelectric power in the world.
What are the positive effects of the Three Gorges Dam? Give 2?
Flooding is estimated to have been reduced from once every 10 years to once every 100 years.
It provides 3% of China’ energy demand.
The reduction in flooding has made it safer to travel up the river.
What are the negative effects of the Three Gorges Dam? Give 3?
When the reservoir is full, it is estimated 13 cities and 1300 villages will be submerged, forcing 2 million people to relocate.
The reservoir will also flood farmland, 650 factories and 1300 sites of cultural and historical interest.
The sediment carried by the river could cause the dam to fail, causing catastrophic flooding like never seen before.
The dam could destroy habitats and endanger species.
The Three Gorges Dam will relocate some water to other rivers, causing increased flooding elsewhere.
What are the disadvantages of levees?
When levees break, they add to the volume of water in a flood. This meant many levees had to be reinforced.
