Flood Risk Soft And Hard engineering Flashcards
Flood warning and preparation
There are three stages of warning and they use satellites and technology to measure rainfall so they can warn others
Benefit of flood warnings
Cheap
Protect property
Saves lives 24/7
Makes people feel secure
Flood warning ⚠ benefits
Doesn’t stop floods
People need to take action and people may ignore warning
Education is required
Flood plains zoning
Further away buildings are to river the more important it is
Don’t build in the flood risk areas
Flood plains zoning benefits
Low cost
Flood plains zoning downfalls
Could be costly to demolish homes
Planting trees
Plant trees across floodplains reduces floods as rain gets intercepted by trees by roots
Benefits of planting trees
Reduce surface run off during heavy rain episode More carbon capture Cheap Reduce water flowing down streams Aesthetically pleasing
Disadvantages of planting trees
May need to remove concrete
Can look unpleasant at first with baby 👶 trees
Examples of planting trees
Welsh government are funded by woodland trust ™ to 🌿 plant 10 million trees
River restoration example
River quaggy scheme in south East London which protects 600 houses from being flooded this increase more people going to Sutcliffe Park
Cost 1.1 million
Benefits of river restoration
New wetland
New biodiversity
Reduce flooding risk
Aesthetically pleasing
Disadvantages of river restoration
Lost of agriculture land
Expensive
Urban areas
Building on flood plains creates Impermeable land water is transferred quickly via drains
Rapid movement in water increases flood risk
Deforestation
Water is taken by trees and is used up
When you remove the trees more water is available and is transferred rapidly to channels increasing flood risk
Farming
Arable farming causes soil to be exposed to the elements which leads to surface run off
Dams
These are built in the course of the river channel to control the amounts of water that flows through they hold and release water
Water is store in reservoirs
Dams disadvantages
Damn expensive Settlement may be lost Farmland lost Sediment are trapped can lead to erosion further downstream Farmland becomes less fertile
Examples of dams
Kielder water is the largest in European man made lake
Has a hydroelectric plant
Controls flows of Tyne
Channel straightening
Digging a straight channel which water will flow through this speed up the water from flood prone locations
Channel straightening disadvantages
Cause flooding downstream
More erosion down streams due to rapid water 💦
Channel straightening example
River ouse York
It still flood though 3 000 residents left due to this
Embankments
Raise walls along river
Increase amount of water stored in river bank
Looks pleasant if cared for
Embankments
Raise walls along river
Increase amount of water stored in river bank
Looks pleasant if cared for
Embankments disadvantages
Expensive
Takes a lot of space
Severe flooding if it breaks
Embankments example
Thames embankments from 19th century
Reclaim marshy land next to river in central London used granite from Cornwall
Flood relief channel
River discharge is reduced so flooding reduce and is prevented gates can be added to control river release
Flood relief channels disadvantages
Increase discharge where the relief chanel rejoins the river or another river this can cause more flooding in the area
Flood relief channels
Lea Valley between Hertfordshire and Stratford East London in 1976 these were installed and no major flood had ever occur
