Hard Engineering Flashcards
What are the four types of hard engineering?
- Embankments (levees)
- Flood Relief Channels
- Dams and Reservoirs
- Channel Straightening
What are the social benefits of embankments?
- safer from flooding
* walking routes for locals and tourists
What are the economic benefits of embankments?
Cheap compared to other methods.
What are the environmental benefits of embankments?
Earthen embankments create habitats for riverbank animals.
What are the social costs of embankments?
- Deprives people of easy access for fishing and boating
* Not as reliable as other methods so gives people a false sense of security, possibly leaving them unprepared
What are the economic costs of embankments?
- Higher maintenance costs
* Earthen ones prone to erosion which will increase downstream sedimentation. This will incur a dredging cost.
What are environmental costs of of embankments?
- If breached water stays on land for a long time as it has restricted access to the river
- Gabions and concrete displace animals
- Concrete may break causing mesh or concrete slabs to litter the river bank
What are the social benefits of flood relief channels?
- Decreases flood risk
- New footpaths and cycle tracks
- Calm water is good for canoeing and boating
- Birdwatching and nature reserves can be set up
What are the economic benefits of flood relief channels?
- Insurance costs are lower
- Values of houses increase
- More secure for setting up business ventures
What are the environmental benefits of flood relief channels?
- Provides new habitat
* Tranquil setting when full of water
What are the social costs of flood relief channels?
- People moved
* Downstream settlements have increased flood risk
What are the economic costs of flood relief channels?
- Expensive
- Run out of funds
- Need maintenance and repair
- Take a long time to plan and build
What are the environmental costs of flood relief channels?
- Habitats destroyed
- Variable water levels causes unreliable habitats
- look unattractive at times of low flow when concrete and gabions are exposed
What are the social benefits of damns and reservoirs?
- source of drinking water
- provides hydroelectric power
- Highly effective against floods
- Boosts tourism
What are the economic benefits of damns and reservoirs?
- boosts tourism
- provides hydroelectric power
- highly effective against floods
What are the economic benefits of damns and reservoirs?
- Surrounding areas may be planted with forests
- promote new habitats
- provides hydroelectric power
What are the social costs of damns and reservoirs?
• displaces people, especially farmers
What are the economic costs of damns and reservoirs?
- Expensive
- money may be lost if there is a loss of industry and decreased demand for water
- soils downstream can become less fertile due to lack of sediment, decreasing crop yields
What are the environmental costs of damns and reservoirs?
- Concrete interferes with migrating fish and their spawning grounds
- Algae collects behind the dam, deoxygenating the water
- Sudden water release could cause downstream bank erosion
- Could trigger an earthquake
- Landslides could occur at reservoirs
What are the social benefits of channel straightening?
Reduces flood risk.
What are the economic benefits of damns and reservoirs?
- Reduced length and straightened course can improve navigation, increasing trade at ports
- Home owners gain confidence in their property and have lower insurance rates.
What are the social costs of channel straightening?
• when water meets a meandering section downstream the velocity is reduced. This causes sedimentation of the channel, increasing flood risk for other areas
What are the economic costs of channel straightening?
• Expensive to straighten and dredge the river, which is necessary to prevent silt accumulation downstream
What are the environmental costs of channel straightening?
- changes in hydrology and downstream flooding can endanger and destroy habitats as the river’s ecosystem has changed
- Visually unattractive
- Deprives animals from burrowing
- increased pollution on land from agrochemicals as runoff cannot easily drain into the river
