L6 - High and dry? Flashcards
Give examples of 4 hard-engineering techniques used to reduce the chance of flooding.
Embankments (levees) (£)
Flood walls (££)
Demountable flood barriers (£)
Flood/storm surge barriers (££-£££)
What are the advantages and disadvantages of embankments?
PROS - stop water from spreading to settlements
Look natural as they can be earth and brass banks
CONS - water may go over the top and get trapped
The water can burst under pressure and cause more damage
What are the advantages and disadvantages of flood walls?
PROS - prevent water from spreading to areas where it would have high impact - e.g. housing
CONS - expensive, unnatural aesthetically, cause flooding downstream where there aren’t flood walls
What are the advantages and disadvantages of demountable flood barriers?
PROS - aren’t permanent, up when needed, used where permanent flood wall would be ugly
CONS - can only be used in specific locations
risk that defence is not installed in time
What are the advantages and disadvantages of flood/storm surge barriers?
PROS - gates can be closed when storm surge is incoming
protect large areas
CONS - construction cost is high and regular maintenance needed
Give 2 examples of soft engineering techniques used to reduce the risk of flooding.
Flood-plain retention - strategies to maintain and restore the rivers original flood plains
River restoration - strategies used to restore rivers original course
What are the advantages and disadvantages of flood plain retention?
PROS - allowing river flooding helps recover natural sedimentation processes and restore soil structure to help efficiency with water storing in soil
CONS - allowing land to flood means land use change and damage
What are the advantages and disadvantages of river restoration?
PROS - taking away embankments and restoring meanders to allow rivers to flood but slows them down, more attractive for recreation and benefits wildlife and natural habitats
CONS - blood banks still needed as land use change brings disadvantages.
