Rivers

Question 1

Attrition

Answer 1

two small pebbles knock against each other- rounder, smaller (sediment)

Question 2

abrasion

Answer 2

rocks carried on river bed sandpapering effect

Question 3

Hydraulic action

Answer 3

Air and water gets trapped in cracks in the bank causing them to get wider due to the pressure

Question 4

solution

Answer 4

dissolved rock in water - affects soft rock like limestone

Question 5

traction

Answer 5

boulders roll on sea bed

Question 6

saltation

Answer 6

pebbles bounces along the river bed

Question 7

suspension

Answer 7

finer sand and silt sized particles carried above sea bed in the flow

Question 8

solution

Answer 8

dissolved materials flow thorugh river (not visable)

Question 9

upper course

Answer 9

slim, less erosion as river donest have a lot of energy, more friction
shallow, large sediment little erosion
vertical erosion
estuaries, deltas. floodplains

Question 10

middle course

Answer 10

meanders, oxbow lakes
lateral and verticle erosion
less friction

Question 11

lower course

Answer 11

widest part
most erosion
lateral erosion
waterfalls
deep wide

Question 12

causes of flooding

Answer 12

urbanisation-
deforestation-
prolonged rainfall-
steep land-

Question 13

causes of flooding

Answer 13

urbanisation-
deforestation-
prolonged rainfall-
steep land-

Question 14

reasons river drops its load

Answer 14

shallower, the volume of water decreases, the river loses energy e.g. beach

Question 15

Jubilee river

Answer 15

Jubilee river channel is a flood relief channel for the river Thames

Question 16

why was it needed?

Answer 16

River Thames area is low-lying & lots of urbanisation meaning easy to flood. Lots of expensive areas that needed protecting e.g. Windsor and Eton (incl. the fancy school)

Question 17

management straergies

Answer 17

built the Jubilee river channel so that extra water from the Thames could go along this channel instead. Cost £110 million, includes 5 weirs.

Question 18

social issues

Answer 18

3,000 properties protected in Eton and Windsor BUT downstream cheaper properties were made more at risk from the scheme.

Question 19

economic issues

Answer 19

unprotected properties in Wraysbury have extremely expensive insurance

Question 20

interlocking spurs

Answer 20

river at the upper course doenst have a lot of energy
water bends around harder rock
due to lack of energy erodes laterally

Question 21

estuaries

Answer 21

found at moth of river
where valley is at its widest
water here is tidal
when river floods over banks it carries salt and silt onto the valley floor
as the tide reaches hiest it has little energy so deposits sediment
over time mud flats
when tide low exposed