IGCSE Geography Rivers Flashcards

Excludes fieldwork (imported from Quizlet)

abrasion (sandpaper action)

material carried in the river scrapes and wears away at the river bed, causing the river to widen and deepen

attrition

rocks in the flow of the water knock against each other, causing rounder and smaller loads

biological weathering

roots of plants grow in the cracks of a rock and splits it

characteristics of middle course river land forms

• less vertical erosion; more lateral erosion

• deeper wider

• deposition at inside band

characteristics of upper course river land forms

• narrow and shallow

• vertical erosion

chemical weathering

weathering by acid rain, causing decay

cons of channelisation

• alters ecosystem

• flood downstream

cons of dams

• expensive

• destructions

• traps sediment > dam failure

cons of levees

• expensive

• breaching

creeping

soil moves slowly

deposition

deposition occurs when the river doesn't have enough energy to carry the material any further

drainage basin

an area of land drained by a river and its tributaries

environmental effects of flooding

• loss of wildlife

• land slides

• destroy vegtation

• spread pollutants

erosion

wearing away and removal of rocks by the action of water wind or ice

factors affecting the amount of discharge

1. size of basin

2. vegetation

3. rainfall

4. land saturation

5. steepness

6. human land use (urbanisation)

factors affecting the speed of river discharge

1. rock type

2. human land use

3. relief

4. external climate

factors effecting deposition

reduction of gradient
reduction in volume of water
increasing friction from bed and banks

features of a drainage basin

• main channel

• confluence

• tributaries

• watershed

• estuary

• source

features of a waterfall

\> cap rock
\> overhang
\> less resistant rock
\> scree
\> plunge pool
\> gorge

flooding effects on humans

• outbreak of waterborne diseases

• injuries, deaths

• loss of properties

• destroy infrastructures

• contamination

• expensive rebuilding

groundwater flow

flow of water at the aquifer until it reaches the river

hard managements for flooding

• dams

• levees

• channelisation

• floor barriers

HIC water usage

70% agricultural
20% industrial
10% domestic

human causes of flooding

• urbanisation

• deforestation

• agriculture

• soil erosion

• climate change

hydraulic action

water is forced into cracks in the bed and pressure expands the cracks further

hydrological cycle

the global circulation of water between the atmosphere, lidosphere, biosphere and hydrosphere

hydrological cycle order

\> precipitation
\> interception
\> stem flow/drip tip
\> surfacae runoff
\> infiltration
\> through flow
\> percolation
\> groundwater flow
\> evapotranspiration
\> condensation

Infiltration/Percolation

Downward movement of water through soil rock due to gravity.

mass movement

the bulk movement of substance due to gravitational pull

middle course river land forms

• meander

• levees

• oxbow lakes

natural causes of flooding

• prolonged period of intense rainfall

• rapid snowmelt

• impermeable rock

• steep relief > lower course flooding

• vegetation

physical weathering

caused by temperature or climate changes

precipitation

Any form of water that falls from clouds and reaches Earth's surface.

pros of channelisation

- increase velocity and reduce friction

pros of dams

• prevent flooding downstream

• multi purpose

pros of levees

- can still use flood plain

River Processes

erosion, transportation, deposition

rockfall

big material falling fast

saltation

small material bounces in small hops along the river bed

slamping

material slides along bedding planes

soft engineering for flooding

• land use planning

• afforestation

Solution

river water reacts with alkaline in the bed and banks dissolving them

solution

soluble material dissolved in river water and transported downstream

suspension

fine loads being carried along by the river flow

Three Gorges Dams cons

• flooded 13 cities, 140 towns, 1350 villages

• 1.4 million people relocated

• temples and monuments destroyed

• polluted by industrial wastes

• 3000 earthquakes since building of dam

• loss of wildlife; Yangtze Dolphins

• expensive $131.3 million

Three Gorges Dams facts

• 2009

• Yangtze River

• 185 km high

• 2 km wide

• 600 km far; ShangHai to ChongQing

• reduced flooding risk

Three Gorges Dams pros

• 6% of China's energy

• flood control for WuHan

• irrigation

• navigation

• tourism

through flow

the flow of water between ground surface and the top of ground water store, moves slowly under the influence of gravity until it reaches a body of water

traction

heavy material is rolled along the river bed

transportation

the movement of material downstream. The bigger the material the more energy the river needs to carry it

Types of mass movement

rockfall, slamping, creeping

types of transport

traction, solution, suspension, saltation

types of weathering

physical, chemical, biological

upper course river land forms

\> V-shaped valleys
\> interlocking spurs
\> waterfalls and gorges

virtual water

Water that is not directly consumed but is used to produce food and other products.

Water management

• collection

• purification

• delivery

Water pollution from farms

fertiliser leaching
eutrophication
increased bacteria growth and deoxygenation

Water pollution from industries

• chemical run-off

• oil spillage

• factory wastes

• offshore dumping of sewage sludge

Water pollution from other sources±§§§§

• domestic untreated sewage

• chlorinated swimming pools

Water purification methods

• filtration and sedimentation

• bacterial disinfection

• microorganisms: chlorination

• minerals: aeration

weathering

the breaking down or dissolving of rocks in situ