Yangtze River floods year
1998
Physical causes of Yangtze River floods
Excessive rainfall
Melting of deep snow accumulated at Qinghai-Tibet plateau
Human causes of Yangtze River floods
Deforestation
Human impacts of Yangtze River floods
3,004 deaths
15 million homeless
Farmers have to plants to harvest
Damage to health, educational and water facilities
Roads, bridges, irrigation systems and other infrastructure damaged
Physical effects of the Yangtze floods
Damaged crops and plants in environment
Soil erosion
Silting
Benefits of 3 gorges dam
Largest dam structure
No power cuts for residents
Makes transport easier
Reduced flood risk
Releases same energy as 15 nuclear reactors
Efforts made to reduce impact of Yangtze flood
Existing dams and levees intended to reduce impacts but failed, making flooding worse
8 million responders reinforced or repaired 300km of breached levees
Evacuation order from govt. of 15-19 million people - 1.5 million onto levees or temporary shelters
Charities such as Red Cross of china allocated more that 30 million for immediate relief supplies
Cons of 3 gorges dam
£23 billion
1.5 million displaced with no money from the government bring fully paid as compensation
Authorities criticized for lack of care for this expropriated
Valleys flooded during construction
Negative changes to biodiversity- fish can’t swim upstream, dolphin may be extinct
Fishermen banned from river
Water polluted more that before as lower velocity prevents River from renewing itself
Dam example
Mulunguzi dam - Zomba
River dredging example
River Thames in London
Continuous efforts
Regular maintenance ensures navigability for commercial and leisure vessels.
Diversion spillways example
Wilson reservoir - Nevada
United States
Concrete channel built next to a dam so the dam doesn’t break in times of very high discharge
Forecast system example
Bangladesh’s flood forecastssting and warning centre
Uses hydrological models and remote sensing to predict flooding in Ganges river basin
Afforestation examples
Loess plateau in china
Soil erosion and flooding problems
In 2000, grain four green project returned slope crop lands to grassland or forest to increase vegetation coverage
Straightening river channel examples
River Thames, London , uk
Levee example
Mississippi River levee - USA
Over 5,600 km long
