Soft Engineering Flood Management

Question 1

Define Soft Engineering.

What are the general advanatages?

Answer 1

Soft engineering defences use knowledge of the whole river basin and its processes, to try to work with nature in order to reduce flooding.

General advantages are:

• They’re cheaper to maintain than hard engineering defences - this is especially important for poorer countries i.e. LEDCs.
• Flooding is more predictable, reducing the risk of an unexpected disaster.
• They can improve opportunities for recreation, such as fishing.
• Some people think they’re more attractive than hard engineering schemes - more aesthetically pleasing.

Question 2

Explain Land Use Management.

Answer 2

Land Use Managment

How it works:

Planning restrictions prevent buildings or roads being constructed on the flood plain. Use of the flood plain is restricted to things such as playing fields, allotments or parks. More water can infiltrate so there’s less surface run off, which reduces discharge and flooding.

Extra Benefits:

• There are no new buildings or roads on the flood plain to be damaged, so the impact of any flooding is reduced.
• It provides recreational opportunities e.g. football fields.

Disadvantages:

• It restricts development. This is especially a problem when there’s a shortage of housing.
• It can’t be implemented in areas that are already urbanised.

Question 3

Explain Wetland and River Bank Conservation.

Answer 3

Wetland and river bank conservation

How it works:

Wetlands store flood water and also slow it down. This reduces flooding downstream. So conserving or re-establishing wetlands gives natural protection from flooding. Planting riparian buffers (trees and shrubs) along the river bank increases interception and lag time, and reduces discharge. In turn, this reduces flooding.

Extra benefits:

• Vegetation protects the surface soil from erosion.
• The vegetation provides habitats for wildlife.

Disadvantages:

• Less land is available for farming - less money into local economy, less local jobs and less local produce.

Question 4

Explain River Restoration.

Answer 4

River restoration

How it works:

• River restoration involves making the river more natural e.g. by removing man-made levees. The flood plain can then flood naturally. As the water spreads out over the flood plain the river’s discharge is reduced (because less water is in the channel), which reduces flooding downstream.

Extra benefits:

• Little maintenance is needed, as the river’s left in its natural state.
• The river provides a better habitat for wildlife.

Disadvantages:

• Local flood risk can increase, especially if nothing’s done to prevent major flooding.

Question 5

The impact of flooding can also be reduced. Explain Weather Forecasts and Flood Warnings.

Answer 5

Weather forecasts and flood warnings

How it works:

• The EA (Environment Agency) monitors weather forecasts, rainfall and river discharge. They warn people about possible floods through TV, radio, newspapers and the internet. This means people can evacuate before the flood happens, saving lifes. People can also move possessions/assets and use sandbags to help reduce damage if flooding occurs.

Disadvantages:

• Some people might not be able to access the communication network.
• Flash floods may happen too fast for warnings.
• People may ignore warnings if they were inaccurate in the past.