River management strategies Flashcards
what are some hard river management strategies?
-dams and reservoirs
-channel straightening
-embankments
-flood relief channels
what are some soft river management strategies?
-flood warning and preparation
-flood plain zoning
-planting trees
-river restoration
how does dams and reservoirs work?
a large concrete barrier built across a river to impede its flow, this causes the valley behind to flood forming an artificial lake (reservoir)
how does channel straightening work?
when a meandering section of a river is engineered to create a widened, straightened and deepened course
how does embankments work?
artificially raised river bank, made by bulldozers moving huge mounds of impermeable soil onto the river banks to build up their heights
how does flood relief channels work?
artificially made channel designed as a backup channel for a river that frequently floods, works like a bypass
how does flood warning and preparation work?
coordinated efforts to devise and carry out action plans for areas at risk, producing a three day flood forecast
how flood plain zoning does work?
land in a river valley is used in such a way to minimise the risk of flooding
how does planting trees work?
planting shelter belts of trees across slopes reduces flooding
what are the costs of channel straightening?
-causes sedimentation of the channel so the rivers more likely to flood
-expensive
-endangers animals and destroys habitats
-changes rivers ecosystem
-the concrete lining deprives burrowing river bank animals of their habitats
-increase pollution
what are the costs of embankments?
-deprive people of easy access to fishing and boating
-presence gives a false sense of security
-need constant monitoring and repair
-if embankments breached, water lays on land for a long time
what are the costs of flood relief channels?
-people have to move out the way of the channel
-expensive
-need to be maintained and repaired
-schemes take a long time to come into affect
-habitats disturbed
what are the costs of flood warning and preparation?
-only effective if people listen
-doesn’t help people in areas prone to flooding
what are the costs of flood plain zoning?
-minimal impact
-difficult to get planning permission
-housing shortage so restricting building doesn’t help
-habitats destroyed
what are the costs of planting trees?
-changed appearance of countryside
-loss of grazing land
what are the costs of river restoration?
-loss of agricultural land
-flooding of crops
-expensive
-not the most practical strategy
how does river restoration work?
when a river has previously been hard engineered is restored to a natural channel
what are the benefits of dams and reservoirs?
-boosts tourism
-promotes new habitats
-source of drinking water
-forestry areas created around reservoirs
-highly effective against floods
-provides hydroelectric power
what are the benefits of channel straightening?
-reduces flooding
-removes sediment that would’ve built up
-improves navigation
-increased trade in ports
-homeowners have more confidence when buying property
what are the benefits of embankments?
-safer from flooding
-habitat provided
-provides walking routes
-cheaper
what are the benefits of flood relief channels ?
-footpaths created
-calm water for boating
-birdwatching and nature reserves may be set up
-insurance costs are lower
-tranquill setting
what are the benefits of flood warning and preparation?
-very cheap
-advanced warning
-ensures peoples safety without high cost of hard engineering
what are the benefits of flood plain zoning?
-low cost
-water meadow protected from development
-provides a welcoming green space
what are the benefits of planting trees?
-reduces surface runoff
-more CO2 absorbed
-adds variety to landscape
