Nat 5 geography (rivers, population, natural disasters) Flashcards
Formation of features in the river
Formation of a v-shaped valley
- River in upper course
- Vertical erosion (hydraulic action and abrasion)
- Deep notch in landscape exposes sides to freeze thaw
- sides get weak and fall into the river (further abrasion)
- Rocks transported downstream
- V-shape valley is formed weaving around interlocking spurs
Formation of a meander
- Middle/Lower course
- Lateral erosion
- River has deep and shallow parts
- River fastest on outer bend eroding it making it deeper (hydraulic action + abrasion). Forms River cliff.
- River is slowest on inside of the bend making it shallower (deposition- dropping of the load). Forms river cliff
Formation of a waterfall
- Upper course
- Water flows over bands of hard and soft rock
- Soft rock eroded quicker than hard
- Erosion creates a plunge pool where the water hits, undercutting the hard rock (hydraulic action + abrasion)
- Hard rock collapses leaving waterfall and a steep sided gorge
Formation of an ox-bow lake
- Middle/Lower course meanders
- Deposition on inside of bend due to slow current
- Erosion (hydraulic action + abrasion) on the outside of bend due to fast current.
- Neck gets narrower as river cliffs meets
- When river has power it takes shorter route over the neck.
- Deposition eventually blocks of the meander bend from the main river leaving an ox-bow lake
Formation of levees
- Levees are natural embankments
- Middle/ lower course
- Times of low flooding river deposits on the river bed raising its height.
- Times of flood river flows over the edge and deposits heavy material on the side of the river.
- Each flood builds up the levees.
High population density (MEDC’s) due to..
Moderate climate fertile farming land low land clean water supply mineral resources good infrastrucutre
low population density (LEDC’s) due to..
Extreme climate extreme relief extreme remoteness infertile land no clean water supply
human factors that affect population
transport and communication jobs government investment quality of housing education healthcare
Physical factors that affect population
relief climate vegetation soils natural resources water supply
Reasons for high birth rate (LEDC’s)
- children needed for workers and to look after elderly
- no family planning or contraception
- many religions frown upon women using birth control
- high infant mortality means many families have back up children
- high status for men if they have a large family.
Reasons for low birth rate (MEDC’s)
- it is expensive to have children
- more women focus on careers
- sexual equality means women choose what they want
- contraception and family planning is widely available
- children are not need for elderly care
Reasons for high death rate (LEDC’s)
Dirty unreliable water poor housing conditions poor access to medical services endemic diseases poor diets that are low in calories or protein
Reasons for low death rate (MEDC’s)
Good housing conditions
safe water
enough food to eat (stronger immune systems)
advanced medical services that are available to all.
how to deal with a rapidly growing population(LEDC’s).
educate about family planning and contraception
extra taxes for parents with large families
rising the age of marriage
Extreme ‘one child policy’
how to deal with an ageing population (MEDC’s)
Giving mothers longer paid maternity
generous child benefits
raise retirement age
