Flood Management Strategies Flashcards
All 16 cards in this deck
What is hard engineering in river management?
Using man-made structures to prevent or control natural processes; usually very expensive but effective at preventing flooding.
What is soft engineering in river management?
Working with nature and natural river processes to reduce flood risk; low cost, low maintenance and little environmental impact.
How do dams and reservoirs reduce flood risk?
A dam traps water in a reservoir, storing it during heavy rain and releasing it in a controlled way; the water also supplies drinking water and HEP.
Give one cost of dams and reservoirs.
Very expensive, and the reservoir floods land and displaces people; trapped sediment and blocked fish migration damage habitats.
What is channel straightening, and how does it reduce flood risk?
Removing meanders so the river is shorter and faster, moving water out of the area more quickly; it also improves navigation.
Give one cost of channel straightening.
It destroys habitats and changes the river's ecosystem; concrete linings are unattractive and faster flow can increase flooding downstream.
What are embankments as a flood management strategy?
Raised banks built along the river so it can hold more water and floods less often, protecting buildings on the flood plain.
Give one cost of embankments.
High maintenance costs and reduced access to the river; concrete or gabion embankments break up habitats and look unattractive.
What is a flood relief channel?
An artificial channel that takes excess water around or away from a settlement when river discharge is high; it can also create new aquatic habitats.
What are flood warnings and preparation?
Monitoring rivers and warning people so they can prepare and act; people may not respond, especially after false alarms.
What is flood plain zoning?
Restricting building and development on the flood plain so land at highest risk is used only for low-value uses such as grazing, wetlands or recreation.
What is river restoration?
Returning a hard-engineered river to its natural channel, e.g. removing straightening or levées, reducing discharge downstream and increasing biodiversity.
Give one cost of planting trees to reduce flood risk.
The land can no longer be used for farming (also: it takes years before young trees have much effect).
Give one cost of a flood relief channel.
Where the channel rejoins the river, discharge rises, which can increase flood risk downstream (also: it is expensive to build).
Give one cost of flood plain zoning.
It does not protect buildings already on the flood plain (also: it limits where a settlement can expand).
Give one cost of river restoration.
Letting the river flood its natural land can increase flood risk locally, for example on nearby farmland.