Hard Engineering -rivers Flashcards
What is hard engineering?
Involve the use of technology to control rivers- building structures that reduce flooding
Disadvantages of hard engineering?
Expensive to build and maintain- need technical knowledge.
Floods happen less often but when they do happen they tend to be more hazardous.
Natural processes are disrupted.
Ugly.
Dams
Huge walls built across rivers, create a reservoir behind ti.
Dam benefits
Can use them to generate electricity.
Steady release of water allows irrigation downstream.
Recreation
Dam disadvantages
Expensive.
Farmland may be destroyed or people have to move for the reservoir.
Dams trap sediment.
Disrupt wildlife. eg fish breeding patterns
Channel straightening
Removing meanders, makes the water flow faster
Channel straightening benefits
Navigating the river takes less time
Channel straightening disadvantages
Flooding may occur downstream as water is carried there faster.
More erosion downstream.
Wildlife lose habitats
Levees
Embankments built along the river bank, so the river can hold more water without overflowing
Levees benefits
Can build on floodplain
Levees disadvantages
Expensive.
If they break the flooding is severe eg. New Orleans
Diversion spillways
Channels that take excess water elsewhere. They reduce the discharge of the river
Diversion spillways disadvantages
There is an increase in discharge when the water re-enters the river or another river.
If the spillways are overwhelmed by water they too could flood increasing the flooded area of land.
Dredging the channel
Keep the channel free from sediment so that more water can flow through it.
