Flood Management Flashcards
Define hard engineering
Uses heavy machinery to build artificial structures which work against nature to reduce the risk of flooding
Define soft engineering
Involves adapting to a river and learning to live with it. Cheeper but often less effective then hard engineering
4 methods of hard engineering
- Dams and reservoirs
- Channel straightening
- Embankments
- Flood relief channels
Name 4 methods of soft engineering
- Flood plain zoning
- Flood warning and precipitation
- Afforestation
- River restoration
What do dams and reservoirs do to reduce flooding
There large concrete barriers built across a river to impede its flow. This causes valley behind the dam to flood forming an artificial lake called reservoir
Whats a benefit of dams and reservoirs
It restricts supply of water downstream which makes no risks of flooding downstream
Whats a problem with dams and reservoirs
If water is released not carefully then theres still a risk of flooding, its very expensive (176m)
What is channel straightening
Meandering section of a river is engineered to create a widened straightened and re opened corse
What are benefits of channel straightening
Improves navigation and reduces flood risk, faster flowing water removes sediments
Problems with channel straightening
It can make the river more likely to flood if it flows through the straight end section too quickly
How does embankments work
Artificially raised river bank, more water is contained in the channel
Benefits of embankments
Reduces flooding, creates habitats, cheap , creates walking routes
Problems of embankments
Requires high maintenance, deprives people of easy access to the river for fishing and boating
How do flood relief channels work
Artificially made channel that is a backup for a river that frequently floods. It runs parallel to the main river
Problems of flood relief channel
People living in the relief channels have to be moved causing disruption and destroyed habitats
How does flood plain zoning work
Where land in a river valley is uses to minimise the impact of flooding
Benefits of flood plain zoning
Risk of flooding is reduces, cheap, meadows by the river are protected
Problems of flood plain zoning
Limited impact, difficult to get planning permission, habitats are destroyed, creates restricted buildings
How do flood warnings work
EA and other agencies co-ordinate efforts to diverse and carry out action plans for at risk areas
Benefits of flood warnings
Cheap way of protecting people and their property
Problems of flood warnings
They are only effective if people listen, it doesn’t help people who live in places prone to flooding
How does afforestation reduce flooding
Planting shelter belts if trees across slopes and woodlands in flood plains reduces the risk of flooding as trees intercept water through roots
Benefits if afforestation
reduces water flowing downstream, more co2 is absorbed
Problems of afforestation
Change in appearance, countryside wooded rather than open grass, loss of potential grazing land
How does river restoration reduce flooding
When a river that has previously been hard engineered is restored to a natural channel
Benefits of river restoration
Creates new wetland habitats and increases biodiversity , increases water storage areas
Problems of river restoration
Loss of agricultural land and flooding of crops
