Flood Management Strategies CASE STUDIES

Flood Management Strategies

Hard Engineering – The Yangtze/ Three Gorges Dam

·         The river flows through China – third longest river in the world (6380 km)

·         Seasonal flooding is common – rainy season from June – August > increase in river discharge causes flooding > huge problems for farmland and major cities

·         Five major floods in the last century (1931, 1935, 1949, 1954 and 1998)

·         Flood of 1954 covered 193,000 km² of land and killed 33,169 people. Over 18 people had to move > covered the city of Wuhan for over 3 months

·         Flood of 1998 killed around 3,000 people and made 14 people homeless

Defences:

·         Many dams (46 planned or under construction) – the biggest is the Three Gorges Dam:

o   101m high – work began in 1994

o   A reservoir is building up behind the dam – it catches rain water, which is slowly released over time – can store around 22 km³ of water

o   Uses the largest hydroelectric power station in the world – 26 turbines

o   Locks have been built alongside the dam to let ships through

·         There are levees along the river – 3600km of levees along the middle and lower parts

Effects:

Positive Effects:

·         Major flooding has been reduced from once every 100 years to once every 10 years

·         Turbines produce electricity – capacity is likely to reach 22.5 gigawatts (enough to supply 3% of china’s demand)

·         It is safer to navigate the Yangtze  - river shipping…