3 Flashcards Preview

geog paper 2- uk physical > 3 > Flashcards

Flashcards in 3 Deck (35)
Loading flashcards...
1

river carries it’s load:

solution
suspension
saltation
traction

2

solution

dissolved chemicals are carried along

3

suspension

tiny sediment particles carried along in current

4

saltation

small stones are picked up and dropped again

5

traction

large stones dragged along

6

river erosion

abrasion
hydraulic action
attrition
solution

7

abrasion

sand and pebbles dragged along wearing it away

8

hydraulic action

water into cracks, breaking it

9

attrition

wearing away as rocks knock together

10

solution

limestone dissolved by acidic rainwater

11

waterfalls formed:

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

12

weathering

biological
physical
chemical

13

biological weathering

small cracks allow roots to penetrate and force rocks apart

14

physical weathering

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

15

chemical weathering

weak acids dissolve alkaline rocks

16

mass movement

process that cause rock material to move downslope

17

rapid mass misvnt

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

18

slow mass movement

(soil creep)
rain dislodging tiny soil particles each time it rains

19

shape of valley affected by

-rate of weathering
-rate of mass movement
-rate of removal of mass movement

20

upper course

(buckden beck)
-small stream/ tributary
-steep gradient
-small rapids and waterfalls
-rainstorm increases river energy

21

middle course

(river wharfe)
-gradient = gentler
-discharge = increase
-velocity = increase
-shape goes from V to U
-flood plain widens

22

lower course

estuary- river meets sea
river- wide and deep

23

velocity

speed of river
(hydroprop)

24

discharge

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