Rivers Flashcards

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1
Q

Define:

  • Drainage Basin
  • Source
  • Tributary
A

Drainage Basin = Area drained by river

Source = Start of river (spring/lake)

Tributary = Small river joining on to big river

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2
Q

Define:

  • Confluence
  • Mouth/Estuary
  • Watershed
A

Confluence = Where 2 rivers meet

Mouth/Estuary = Where rivers meet sea

Watershed = Boundary between drainage basins

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3
Q

What is the difference between lateral and vertical erosion?

A

Lateral Erosion = channel widening

Vertical Erosion = channel deepening

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4
Q

Name the 3 main types of weathering

A

Physical - Freeze thaw

Chemical - Acid rain

Biological - Roots cracking rocks

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5
Q

Name the 3 main types of mass movement

A

Slumping

Rockfall

Soil Creep = soil particles move down slope due to gravity

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6
Q

Describe what happens to each of these river characteristics as the river goes downstream

Width, Depth, Velocity, Discharge, Gradient, Valley Shape

A
  • Widens
  • Deepens
  • Velocity increases
  • Discharge increases
  • Flattens
  • V shape -> U shape -> flat
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7
Q

Name 3 characteristics of an upper course river

A

Vertical erosion

Steep

Narrow

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8
Q

Name 2 landforms found in the upper course of a river, and how they form

A

Interlocking Spurs - low energy river floes around valley sides (spurs) -> interlocking

Waterfalls - Vertical erosion where hard, resistant rock is over less resistant rock

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9
Q

Name 2 landforms found in the middle course of a river, and how they form

A

Meanders:

  • River erodes laterally -> large bends
  • Bends get bigger -> meander
  • Inner bend - slow current, high disposition -> slip-off slope
  • Outer bend - fast current, high erosion -> river cliff

Oxbow Lakes:

  • Erosion -> meander neck to narrow
  • Outer bends meet, river cuts through
  • Meander cut off by main river -> oxbow lake
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10
Q

Name 2 landforms found in the lower course of a river, and how they form

A

Flood plains:

  • River carried lots of sediment
  • Floods -> excess water spills over surrounding area
  • Deposits sediment -> flood plain
  • Floodplain shaped by lateral erosion of meanders

Levees:
- River floods -> sediment deposited on bank (heaviest first)
-

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11
Q

Name 4 physical causes of river flooding, and how they lead to flooding

A

Rainfall Intensity:
- Lots of rainfall in short time -> soil infiltration

Geology:
- Impermeable rocks can’t absorb water

Snow Melt:
- Snow melts in spring -> more water

Drainage Basin:
- Steep valleys and tributaries collect water

All causes lead to:
Excess water -> surface runoff -> more water than channel can hold -> flooding

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12
Q

Name 3 human causes of river flooding, and how they lead to flooding

A

Deforestation:
- Less plants to absorb water

Climate change:
- Melting ice sheets and glaciers -> more water in glaciers

Urbanisation:

  • Rain forced to flow quickly into sewers
  • Man made surfaces = impermeable

All causes lead to:
Excess water -> surface runoff -> more water than channel can hold -> flooding

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13
Q

Give 2 social impacts of the 2011 mississippi flooding

A

Outbreak of water borne diseases

Homes flooded

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14
Q

Give 2 economic impacts of the 2011 mississippi flooding

A

Insurance, fuel and food prices increase

Expensive fertilisers needed to replace washed away nutrients

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15
Q

Give 1 environmental impact of the 2011 mississippi flooding

A

Crops and farmland are destroyed

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16
Q

Explain 3 hard engineering methods used to manage the mississippi river

A

Levees built since 1700s

River straightened

Floodways and cut offs divert water

17
Q

Explain 4 soft engineering methods used to manage the mississippi river

A

Insurance scheme regulates land use on floodplain

Flooded agricultural land bought to store excess water

Resorting upriver wetland areas - soak up extra rainwater

Government funding for farmers. Land -> wildlife conservation reserved & water storage areas

18
Q

Give 1 reason how planning and 2 reasons how prediction can reduce the impact of flooding

A

Planning: Land use zoning

Prediction: Environment Agency monitors rivers

  • forecast potential floods
  • give advanced warnings of flooding
19
Q

Give 4 reasons how prevention and 4 reasons hoe education can reduce the impact of flooding

A

Prevention - Reduce water damage to homes:

  • Use ceramic tiles
  • Raise height of electrical sockets on walls
  • Install heating systems on upper floors
  • LICS build homes on stilts above water levels

Education - spread information:

  • Leaflets and advertising
  • Posting information on website
  • Phone helplines
  • Organising flood drills
20
Q

Explain the advantages and disadvantages of 3 methods of soft engineering

A

Afforestation - planting trees in drainage basin:
Ads - Vegetation soaks up water
- Provides habitats
Dis - Could use land for other purposes

Land Use Zoning:
Ads - Homes and expensive projects can be
located in low risk areas
- Less important located in high risk areas
Dis - Public access may be difficult
- May cause planning problems elsewhere

Washlands - areas allowed to flood:
Ads - Cheap
- Less visual pollution
Dis - Floodplain can’t be used for other purposes

21
Q

Explain the advantages and disadvantages of 3 methods of hard engineering

A

Flood relief channels - extra channels to carry extra water:
Ads - Excess water taken away, stopping it from
flooding nearby land
Dis - Visually unattractive
- Only needed during flood risk
- Expensive to build and maintain

Channelisation - depeening/widening river channel:
Ads - Allows water to quickly flow away from
flood risk areas
Dis - Visually unattractive
- More water taken downstream, increasing
flood risk to other settlements

Embankments - levees built along river banks:
Ads - Use natural materials, so blend in
- Prevent water moving into flood risk areas
Dis - Flood water can spill in extreme conditions
- Can burst under pressure -> widespread
damage