Mississippi River: Evaluation Of River Management Strategies

Question 1

Background information

Answer 1

The Mississippi River, USA, flooded in 2001, forcing 4,400 people to move and causing $13 million of damage.

Question 2

List the two hard engineering strategies used.

Answer 2

1. Raising and strengthening of levees

2. Cutting of meanders

Question 3

List the two soft engineering strategies used.

Answer 3

1. Afforestation

2. Restriction of building

Question 4

Levees

Answer 4

1. Levees were raised to 15 metres and strengthened to enclose the river channel for a stretch of 3000 km.
2. Levees protect the area where they are built from floods.
3. However, they tend to push the problem downstream. This was partly to blame for the 2001 floods.
4. Silt, which should be deposited onto the floodplain, stays in the river. This reduces the river’s capacity, thus decreasing the river discharge required for a flood.

Question 5

Meanders

Answer 5

1. Meanders were cut over a stretch of 1750 km to create a fast-flowing, straight river channel.
2. This moves water away from an area faster which lowers the risk of flood there.
3. However, rivers naturally bend and erode. Therefore, money and time may have been wasted.

Question 6

Afforestation

Answer 6

1. Afforestation has taken place in areas such as the Tennessee Valley to intercept rainfall and stabilise soil.
2. This creates new habitats and may also lower soil erosion.
3. However, afforestation does not directly prevent flooding.

Question 7

Restriction of building

Answer 7

1. Building has been restricted in many floodplain areas. In areas such as Rock Island on the floodplain where housing was already built, it was bought by the county and demolished.
2. This is cheaper in the long term as opposed to compensating owners.
3. However, safe flood zones do not prevent flooding.

Question 8

What should be at the end of the answer?

Answer 8

A summing up statement.

Question 9

What is a hard engineering strategy?

Answer 9

A strategy to control a natural hazard that does not blend into the environment.

Question 10

What is a soft engineering strategy?

Answer 10

A strategy to control a natural hazard which blends into the environment and so is often sustainable.