3 Flashcards

1
Q

river carries it’s load:

A

solution
suspension
saltation
traction

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2
Q

solution

A

dissolved chemicals are carried along

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3
Q

suspension

A

tiny sediment particles carried along in current

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4
Q

saltation

A

small stones are picked up and dropped again

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5
Q

traction

A

large stones dragged along

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6
Q

river erosion

A

abrasion
hydraulic action
attrition
solution

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7
Q

abrasion

A

sand and pebbles dragged along wearing it away

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8
Q

hydraulic action

A

water into cracks, breaking it

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9
Q

attrition

A

wearing away as rocks knock together

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10
Q

solution

A

limestone dissolved by acidic rainwater

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11
Q

waterfalls formed:

A

1) bed of soft and hard rock
2) erosion of less resistant rock creating plunge pool
3) overhang collapses
4) waterfall takes new position leaving steep valley or gorge

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12
Q

weathering

A

biological
physical
chemical

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13
Q

biological weathering

A

small cracks allow roots to penetrate and force rocks apart

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14
Q

physical weathering

A

rock fills with rain, freezes, expands by 10% and breaks rock

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15
Q

chemical weathering

A

weak acids dissolve alkaline rocks

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16
Q

mass movement

A

process that cause rock material to move downslope

17
Q

rapid mass misvnt

A

-landslides and mudflow occur on railway cutting and along cliff coastline

18
Q

slow mass movement

A

(soil creep)

rain dislodging tiny soil particles each time it rains

19
Q

shape of valley affected by

A
  • rate of weathering
  • rate of mass movement
  • rate of removal of mass movement
20
Q

upper course

A

(buckden beck)

  • small stream/ tributary
  • steep gradient
  • small rapids and waterfalls
  • rainstorm increases river energy
21
Q

middle course

A

(river wharfe)

  • gradient = gentler
  • discharge = increase
  • velocity = increase
  • shape goes from V to U
  • flood plain widens
22
Q

lower course

A

estuary- river meets sea

river- wide and deep

23
Q

velocity

A

speed of river

hydroprop

24
Q

discharge

A

Volume of water flowing in River

area(width x depth) x velocity

25
meanders change in valley
1) rivers bend in middle course and water flows naturally in a corkscrew pattern (helicoidal Flow) 2) -helicoidal flow sends river energy laterally -Fastest current (thalweg) forced outer bend where it undercuts bank 3) Erosion creates narrow neck between two meanders Oxbow lake created
26
bradshaw model
summarises the changes to river characteristics from source to mouth
27
increase | from upper to lower source
- river discharge - channel width - channel depth - velocity - sediment load volume
28
decrease | from upper to lower course
- particle size - bed roughness - slope angle
29
storm hydrograph
shows how river reacts to rainfall
30
if lag time is shorter
heavy rain | impermeable surfaces
31
if lag time is longer
less rainfall | rural (permeable surfaces)
32
affect hydrograph shape
- urbanisation | - deforestation
33
antecedent rainfall
rainfall before | saturated soil
34
surface run off
extra rain that soil can’t absorb
35
quickness of surface run off
- antecedent rainfall - permeable/impermeable - heaviness of rainfall - shape of river basin