Hard vs Soft Engineering - Rivers
- Created by: mbull
- Created on: 14-01-18 20:22
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- Hard vs Soft Engineering - Protecting against flooding
- Hard Engineering
- Man-made structures built to control the flow of rivers and reduce flooding.
- Dams and Reservoirs
- Dams (huge walls) are built across the rivers, usually in the upper course.
- A reservoir (artificial lake is formed behind the dam.
- Reservoirs store water, especially during periods of prolonged/ heavy rain.
- Reducing the risk of flooding.
- The water in the reservoir can be used as drinking water and to generate hydroelectric power.
- Dams (huge walls) are built across the rivers, usually in the upper course.
- Channel straightening
- The river's course is strengthened - meanders are cut out by building artificial straight channels.
- Water moves out of the area more quickly because it does not travel as far.
- Flooding may happen downstream as water is carried there faster.
- More erosion downstream.
- Embankment
- Raised walls are built along the river banks.
- River can hold more water.
- It will flood less frequently, protecting buildings on the floodplain
- Expensive
- Risk of severe flooding if water rises above level of embankments
- Flood relief channels
- Channels are built to divert the water.
- Flooding prevented because river discharge is reduced
- Gates on flood relief channels mean release of water can be controlled
- If levels get too high for the relief channels they could also flood.
- Soft Engineering
- Schemes set up by using knowledge of a river and its processes to reduce the effects of flooding.
- Flood warnings
- The Environment Agency warns people about possible flooding through TV, radio, newspapers and the internet.
- Impact of flooding is reduced, gives people time to move possessions.
- Warnings do not stop a flood from happening,
- People may not hear or have access to warnings.
- Preparation
- Buildings are modified to reduce amount of damage a flood could cause.
- Impact of flooding is reduced.
- Preparation don't guarantee safety.
- Expensive.
- Flood plain zoning
- Restrictions prevent building on parts of a flood plain.
- Risk of flooding reduced
- Expansion of an urban area is limited if there aren't any other suitable building sites.
- No help in areas that have already been built on.
- Planting trees
- Increases interception of rainwater and also increases the lag time.
- Discharge and flood risk are reduced
- Less land is available for farming.
- River Restoration
- Involves making river more natural so flood plain can flood naturally.
- Less risk of flooding downstream because discharge is reduced.
- Local flood can increase
- Hard Engineering
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