There are two main ways in which you can manage rivers: hard and soft engineering. Hard engineering focuses on humans trying to control the environment and tends to be more expensive. Soft engineering aims to work with the environment and is more ecologically sensitive.
Hard engineering
Raised river banks
Higher banks means the river can hold more water
One off costs
Relatively cheap
Can be used in local, small-scale projects
Looks unnatural
Increases risk of flooding elsewhere
Straightened river channel lined with concrete
Water will flow quicker through a straighter channel.
One off costs
Stops local flooding
Can be used in local, small-scale projects
Expensive
Increases risk of flooding elsewhere
Deepened river channel
River is deeper so can hold more water
Channel can hold more water
Reduces flooding
Dredging is an annual job
Dams and reservoirs
Trap and store water and release it in an controlled way.
Controls river
Resevoirs are multi-purpose and provide electricity
Very expensive
Reservoirs flood local ecosystems
Dams trap fertile silt
Flood walls
Raised walls built around settlement, industry or transportation
Effective if the flood is not too extreme
Expensive
Looks unnatural
Flood storage areas
Water is pumped from rivers and stored in temporary lakes.
Effective
Relatively natural
Large areas of land needed
Expensive to set up
Tidal barrier
Prevents flooding at high tide.
Protects large areas ‘at once’
Very expensive
Only suitable in estuaries
Soft engineering
Afforestation
Plant trees to increase interception and absorb water
Environmentally aesthetic
Relatively cheap and one-off cost
Large areas of land needed for tree planting
Floodplain zoning
Closeness to river governs landuse.
Land use close to river used for animal grazing
Land furthest from the river used for ‘expensive’ land use, such as hospitals
Does not prevent flooding
Flood prediction and warning
The Environment Agency monitors rainfall and river levels and issues warnings to the public.
Public are aware of the risks and can take appropriate action
Involves many people
Continuous nature means that it is expensive
Does not prevent flooding
Washlands
Parts of the floodplain are allowed to flood.
Prevents valuable land flooding
Land can’t be ‘built’, requires low value land to be available for flooding