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River Flooding - Coggle Diagram
River Flooding
Effects
Loss of property and business
Loss of life
waterborne diseases
Mass Migration
Accidents, overflowing hospitals
agriculture
disease- vectorborne
HOW TO COPE WITH FLOODING-
Evacuate to high ground
Avoid driving
Keep doors shut-animals, water
Do not touch electric equipment
Dont wade in flood water
Causes
Natural
Rocks and Soil type- Impermeable
Saturated/wet soil
Dry soil-baked hard by the sun-crust
Steep slopes
Normal snowcap melting
General rainfall
Human-made
Deforestation
Urbanization
Farming- compaction of soil. Farming is good otherwise
Infra-structure failures
Climate Change
Impermeable surfaces building-roads, etc.
How to cope with flooding- flood management
Hard engineering
Dam construction
Dams are often built along the course of a river in order to control the amount of discharge. Water is held back by the dam and released in a controlled way. This controls flooding.
PROS:
Water is usually stored in a reservoir behind the dam. This water is used for irrigation.
Reservoir water can be used to generate hydroelectric power or for recreation purposes.
Fisheries and tourism can be developed.
CONS:
Building a dam can be very expensive.
Sediment is often trapped behind the wall of the dam, leading to erosion further downstream.
Settlements and agricultural land may be lost when the river valley is flooded to form a reservoir.
Embankments
An embankment is an artificial bank or levee that is raised above the surrounding land to reduce the risk of flooding.
River rerouting, widening, deepening- river engineeirng
Diverting the flow of river channels using canals
Cons- Altering the river channel may lead to a greater risk of flooding downstream, as the water is carried there faster.
Soft engineering
Aforestation
Trees are planted near the river.
This means greater interception of rainwater and lower river discharge.
This is a relatively low cost option, which enhances the environmental quality of the drainage basin.
RIVER MANAGING
Flood plains and then rising land