Flooding (Cambridge (CIE) IGCSE Environmental Management): Flashcards
Exam code: 0680
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When does a river flood?
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When does a river flood?
A river floods when the volume of water is greater than the river's capacity.
Define saturated soil.
Saturated soil is soil that already holds as much water as it can, so it cannot absorb any more.
Why do steep slopes increase flood risk?
On steep slopes, rainwater flows quickly downhill and has no time to infiltrate, so river levels rise sharply.
Urbanisation covers land with surfaces, such as roads and rooftops, that stop water soaking into the ground.
Urbanisation covers land with impermeable surfaces, such as roads and rooftops, that stop water soaking into the ground.
Why does compacted soil increase surface run-off?
Compacted soil has fewer air spaces to store water, so even light rain becomes surface run-off.
True or False?
Storm surges and tsunamis are mainly causes of river flooding.
False.
Storm surges and tsunamis are coastal flooding causes, so they affect coastlines rather than river systems.
How does deforestation increase flood risk?
Deforestation removes trees that intercept rainfall, so more water runs quickly into rivers.
Define storm surge.
A storm surge is a temporary rise in sea level that forms when powerful winds push seawater towards the coast.
Why does climate change bring heavier rainfall?
Climate change brings heavier rainfall because warmer air holds more moisture, so storms carry extra water.
Higher sea levels mean storm surges start from a higher point, so they travel further .
Higher sea levels mean storm surges start from a higher point, so they travel further inland.
Define tsunami.
A tsunami is a giant wave that forms when an underwater earthquake, volcanic eruption or landslide displaces a huge volume of water.
True or False?
All the impacts of a flood are short-term.
False.
Some flood impacts are long-term and last months or years, such as soil too damaged to grow food.
How does floodwater kill crops?
Floodwater kills crops by covering them for too long, which stops them getting the oxygen they need.
How do floods contaminate drinking water?
Floods contaminate drinking water when sewage systems overflow and when chemicals leak from factories, petrol stations and farms into the floodwater.
Stagnant water after a flood creates breeding sites for , which spread malaria and dengue fever.
Stagnant water after a flood creates breeding sites for mosquitoes, which spread malaria and dengue fever.
How can heavy rain trigger a landslide?
Heavy rain soaks into hillside soil, making it heavier and more likely to slip downhill.
Why can flooded homes cause respiratory problems?
Damp, flooded homes grow mould, which makes the air unhealthy to breathe.
True or False?
Landslides caused by flooding lower the risk of future floods.
False.
Landslides destroy vegetation, so the soil loses root support and future flood risk increases.
Why do floods strain government budgets?
Floods strain government budgets because governments must pay for rebuilding roads, bridges and public services.
Which nutrients does flood silt add to farmland?
Flood silt adds nutrients such as nitrogen and phosphorus to farmland.
How does flood silt reduce farmers' spending on fertiliser?
Flood silt makes the soil more fertile, so farmers need to buy less fertiliser.
Some floodwater soaks through the soil into , which are natural underground water stores.
Some floodwater soaks through the soil into aquifers, which are natural underground water stores.
How do scientists monitor flood risk?
Scientists monitor rainfall, river levels and weather patterns using satellites, sensors and computers.
Define land use zoning.
Land use zoning is the use of maps to identify high-risk flood zones and decide which activities are allowed there.
Land use zoning places hospitals and emergency centres on ground, where they are less likely to flood.
Land use zoning places hospitals and emergency centres on higher ground, where they are less likely to flood.
How can building design keep living areas above floodwater?
Builders raise homes on stilts or raised foundations to keep living areas above floodwater.
Why do builders place electrical sockets high on walls in flood-prone areas?
Builders place electrical sockets high on walls so they stay dry and safe during floods.
Define disaster preparation.
Disaster preparation is getting communities ready for a flood through plans, drills, emergency supplies and rescue teams.
Why do planners set evacuation routes in advance?
Planners set evacuation routes in advance to avoid roads that may flood first.
Flood shelters reduce the risk of illness because is easier to control there than in flooded homes.
Flood shelters reduce the risk of illness because hygiene is easier to control there than in flooded homes.
How can rebuilding reduce future flood damage?
Rebuilding can make structures stronger and more flood-resistant, for example by raising roads and widening drains.
What does international aid provide after severe flooding?
International aid provides emergency food, medicine, clean water, tents and rescue teams, plus money to rebuild homes, infrastructure and schools.
True or False?
Flood monitoring and warning technology always works, even during storms.
False.
Monitoring technology can fail in storms or in remote areas.
What must people do for flood warnings to be useful?
Flood warnings are only useful when people understand and trust them.
True or False?
Land use zoning is easy to introduce in older settlements.
False.
Zoning is hard to introduce where older settlements are already built on floodplains.
How does land use zoning let floodplains reduce flood damage?
Zoning keeps floodplains free of buildings, so they can absorb water naturally.
Why is flood-resistant building design hard for poorer communities to adopt?
Raising or adapting buildings has high building costs that poorer communities often cannot afford.
True or False?
Everyone can leave quickly once a flood evacuation begins.
False.
Elderly or disabled people may struggle to leave quickly.
What does disaster preparation need in order to keep working?
Disaster preparation needs regular funding, training and community participation.
Why can flood shelters struggle during large floods?
Flood shelters have limited space and resources during large floods.
Why can rebuilding fail to reduce future flood risk?
Rebuilding in the same high-risk areas may simply repeat the problem.
Long-term dependence on international aid can weaken local .
Long-term dependence on international aid can weaken local resilience.
Why can international aid slow flood recovery?
International aid can slow recovery because it may take time to arrive.
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