River management Flashcards
How can dams be used to control flooding?
They are built along the course of a river to control the amount of discharge. Water is held back by the dam and released in a controlled way
How could dams cause losses for local people?
Settlements and agricultural land may be lost when the river valley is flooded to form a reservoir
How do dams lead to erosion further downstream?
Sediment is trapped behind the wall of the dam
Cost of building dams
Expensive
How can river engineering be used to increase the amount of water the river can carry?
The river channel can be widened or deepened
What can be built on the river as a method of river engineering?
Protective Levees
Disadvantage of altering a river channel
It could increase the risk of flooding downstream, as water is carried there faster
How can river engineering be used to make water travel faster along its course?
The river channel can be straightened
How can flood waters be directed away from settlements?
The channel course of the river can be altered using river engineering
How does afforestation help to reduce river flooding?
Trees are planted next to the river, leading to greater interception of rainwater, a lower discharge and less surface run-off
Disadvantage of afforestation as a solution to river flooding
The land can’t be used for settlements and farming
Managed flooding
When the river is allowed to flood naturally in some places to prevent flooding in other areas e.g. near settlements
Disadvantage of managed flooding
Can destroy animal habitats
Planning
Local authorities and the national government introduce policies to control urban development close to or on the flood plain
How does planning help with flood control?
It reduces the chance of flooding in property
