rivers

Question 1

source

Answer 1

start of the river

Question 2

watershed

Answer 2

boundary of drainage basin

Question 3

tributary

Answer 3

small river in a drainage basin

Question 4

drainage basin

Answer 4

area of land drained by a river system

Question 5

mouth

Answer 5

end of river

Question 6

confluence

Answer 6

where one tributary joins another

Question 7

precipitation

Answer 7

forms of rainfall

Question 8

interception

Answer 8

where water is prevented from reaching the surface

Question 9

percolation

Answer 9

when rainwater enters rock

Question 10

overland flow

Answer 10

rainwater flowing on land

Question 11

infiltration

Answer 11

rainwater travelling through soil

Question 12

base flow

Answer 12

water flowing from rock into the river

Question 13

through flow

Answer 13

water travelling through soil

Question 14

permeable surface

Answer 14

allows water to go through it

Question 15

examples of permeable surfaces

Answer 15

sandstone, limestone, chalk

Question 16

impermeable surfaces

Answer 16

surfaces that do not allow water through it

Question 17

examples of impermeable surfaces

Answer 17

granite, man-made surfaces

Question 18

what is the difference between erosion and weathering

Answer 18

weathering:
movement is not involved (in situ)
material is angular (Scree)

erosion:
movement is involved
materials are rounded and smooth

Question 19

what is SCREE

Answer 19

bits of rocks that fall off the cliff face

Question 20

what is in situ

Answer 20

natural material or processes prior to transport

Question 21

what is vertical erosion and what does it do

Answer 21

• erosion downwards
• deepens a river valley
• makes V-shaped valleys

Question 22

what is lateral erosion and what does it do

Answer 22

erosion sideways
widens a river system
forms meanders
oxbow lakes

Question 23

what is the sinosity of a river

Answer 23

the bendiness of a river

Question 24

hydraulic action

Answer 24

• force of the river against the banks which causes air to be trapped in cracks
• the pressure wakens the banks and gradually wears it away

Question 25

abrasion/corrasion

Answer 25

- rocks carried by the river wear down the river bed of the banks

Question 26

attrition

Answer 26

- rocks being carried by the river smash into each other and break into smaller pieces

Question 27

solution

Answer 27

- soluble particles are dissolved into the river

Question 28

suspension

Answer 28

- fine light minerals are carried along the water

Question 29

traction

Answer 29

- large boulders and rocks are rolled along the river bed

Question 30

saltation

Answer 30

- small pebbles and stones are carried along the river bed

Question 31

when does deposition occur

Answer 31

- when there is low discharge during a period of low precipitation - less velocity when a river enters a sea or lake - shallow water occurs on the inside of a meander - the load suddenly increases (debris from a landslide) - a river overflows its banks

Question 32

interlocking spurs

Answer 32

hillsides that make up a v-shaped valley

Question 33

cross profile

Answer 33

A cross-section of the valley and channel of a river

Question 34

how is erosion formed on the outside of the bend

Answer 34

- water around a bend is pushed towards the outside - causing increased speed erosion

Question 35

river cliff

Answer 35

Steep bank created on the outside of a river bend

Question 36

what causes undercutting of the bank to form a river cliff in a meander

Answer 36

The lateral erosion on the outside bend

Question 37

describe and explain the inside bend of a meander

Answer 37

- Water on the inner bend is slower, causing the water to slow down and deposit the eroded material - creating a gentle slope of sand and shingle

Question 38

slip off slope

Answer 38

The build-up of deposited sediment

Question 39

when do levees form

Answer 39

when there is an increase in the volume of water flowing downstream and flooding occurs

Question 40

levee

Answer 40

a natural embankment, built up when the river overflows

Question 41

peak discharge

Answer 41

maximum amount of water held in the channel

Question 42

peak rainfall

Answer 42

maximum amount of rainfall (millimetres)

Question 43

lag time

Answer 43

the time taken between peak rainfall and peak discharge

Question 44

rising limb

Answer 44

shows the increase in discharge on a hydrograph

Question 45

falling limb

Answer 45

shows the return of discharge to normal/base flow on a hydrograph

Question 46

base flow

Answer 46

the normal discharge of the river

Question 47

factors that effect lag time

Answer 47

- size of drainage basin - vegetation - valley side steepness - soil type

Question 48

characteristics of an estuary

Answer 48

- wider mouth - creation of mudflats