building dams affects river transportation process 

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building dams affects river transportation process

building a damn across a river to control flooding interferes with the rivers ability to carry its load of sediment frpom source to sea

huge resevoirs are created behind behind the dams and the rivers load is trapped

3 gorges damn

15m high

1.6km wide

built along yangtze river

560km long resevoir

HEP is used to prevent floods in shanghai

effects

prevented transport of fertile alluvium downstream

floods have been prevented but farm land has become infertile

farmers now have to buy expensive alluvium

1.3m people relocated due to contrusction of dam

damage to ecosystem and wildlife

increase risk of landslides

river rhine

766 miles long

flows through 6 countries

aince 1950 13 HEP power stations were built which has increased the chance of flooding

effects

river floods on a anual basis since 1990

25000 in netherlands had to evacuate due to floodinf