Paper 2-Rivers

Question 1

What is transportation?

Answer 1

Rivers move material downstream(solution, saltation, traction and suspension).

Question 2

What is the channel?

Answer 2

The bed and banks of the river.

Question 3

How are materials transported through solution?

Answer 3

Dissolved chemicals are carried along in solution invisible to the eye.

Question 4

How are materials transported through suspension?

Answer 4

Tiny particles of sediment are carried in suspension in the rivers current.

Question 5

How are materials transported through saltation?

Answer 5

Smaller stones or pebbles are picked up and then dragged and dropped again. This results in a skipping motion called saltation.

Question 6

How are materials transported through traction?

Answer 6

Large stones are dragged along by traction.

Question 7

How does abrasion cause erosion?

Answer 7

Sand and pebbles are dragged along the river bed or knock into it by saltation causing erosion.

Question 8

How does attrition cause erosion?

Answer 8

Where rocks and stones wear each other away as they knock together.

Question 9

How does hydraulic action cause erosion?

Answer 9

Where fast-flowing water is forced into cracks. Breaking up the bank over time.

Question 10

How does solution cause erosion?

Answer 10

Where alkaline rocks such as limestone are dissolved by acidic rainwater.

Question 11

Where do waterfalls form?

Answer 11

The upper course.

Question 12

What is the process of a waterfall forming?

Answer 12

YT-Higher geography-The formation of waterfalls

Question 13

What is biological weathering?

Answer 13

Small cracks allow plant roots to penetrate in search of water and nutrients, as they grow, root cells force the cracks apart. Widening them and breaking the rock into pieces.

Question 14

What is physical weathering?

Answer 14

Physical force breaks rock into pieces.

Question 15

What is freeze thaw weathering(type of physical weathering).

Answer 15

In winter, cracks in rocks fill with rain, this freezes expanding in volume by 10% and widens the cracks so more water can get it. When it is repeated pieces of rock will break away causing scree.

Question 16

What is chemical weathering?

Answer 16

Any chemical change or decay of solid rock. Rainwater can mix with atmospheric gasses to form weak acids which dissolve alkaline rocks such as limestone.

Question 17

What is mass movement?

Answer 17

Means all processes that cause rock material to move downslope due to gravity.

Question 18

What is rapid mass movement?

Answer 18

Landslides and mudflows.

Question 19

What is slow mass movement.

Answer 19

Soil creep caused by rain dislodging tiny soil particles each time it rains.

Question 20

What three things affect the shape of the valley?

Answer 20

The rate of weathering, the rate of mass movement and how quickly the river can remove the material brought by mass movement.

Question 21

What increases as you go downstream?

Answer 21

Discharge, channel width, channel depth, average velocity and load quantity.

Question 22

What decreases as you go downstream?

Answer 22

Load particle size, channel bed roughness, slope angle.

Question 23

What forms in the upper course?

Answer 23

V-shaped valleys, vertical erosion, waterfalls.

Question 24

What form in the middle course?

Answer 24

Meanders and oxbow lakes.

Question 25

What forms in the lower course of the river?

Answer 25

River delta, lateral erosion, flood plains, river beach. Mudflats and saltmarshes.

Question 26

What is velocity?

Answer 26

The speed of a river in m/s.

Question 27

What is discharge?

Answer 27

The volume of water flowing in a river measured in cubic metres/s.

Question 28

What is a meander?

Answer 28

A sharp bend.

Question 29

What pattern do rivers flow in?

Answer 29

Helicoidal flow. And sends the rivers energy in a lateral direction.

Question 30

What is an estuary?

Answer 30

When river meets the sea.

Question 31

What is a floodplain?

Answer 31

An area of low lying ground adjacent to a river. Formed mainly of river sediments and subject to flooding.

Question 32

What is a levee?

Answer 32

Natural or man made embankment to prevent overflow of flood plain.

Question 33

What is a delta?

Answer 33

When it extends past the coastline.

Question 34

What is the interception zone?

Answer 34

Leaves and branches of plants trap a lot of the rain that falls so it does not go directly into the river.

Question 35

What does the level of interception depend on?

Answer 35

Type of plant and season, deciduous plants(those which lose leaves in winter) intercept more rain in summer.

Question 36

What is infiltration?

Answer 36

Some intercepted water is evaporated whereas the rest drips from the leaves to the soil and soaks in, this is infiltration.

Question 37

What is surface run off?

Answer 37

Eventually the soil becomes saturated and cannot take any more. Any extra rain flows over ground called surface runoff.

Question 38

What changes the speed of surface-runoff?

Answer 38

Antecedent rainfall-how much rainfall has fell recently as more will saturate the soil and cause runoff.
How permeable the geology and rock type are.
How heavily the rain falls as heavy storms cause low infiltration and rapid runoff.
The shape of the river basin as a circular shape causes increased flood risk whereas longer, thinner shapes have a low flood risk.

Question 39

What happens once water enters the soil?

Answer 39

Some is taken up an transpired.
Some seeps into the river through soil air spaces known as throughflow.
Some continues onto solid rock and saturates it, the upper limit of saturated rock is known as the water table. From here water slowly seeps to the river known as groundwater flow. This keeps a river flowing when there is no rain.

Question 40

What factors influence a hydrograph’s shape?

Answer 40

Land use change-buildings and roads are not permeable so they increase runoff so reduces lag time(time from rain getting to river)urbanisation causes this.
Deforestation-Reduces interception and infiltration. Afforestation has the opposite affect.

Question 41

What are tributaries?

Answer 41

A river stream that flows into a larger river and increases flood risk.

Question 42

What are hard solution to deal with flooding?

Answer 42

Structures built to defend areas from floodwater.

Question 43

What are soft solutions to deal with flooding?

Answer 43

Adapt to flood risk and allow natural processes to deal with rainwater.

Question 44

What are flood walls?

Answer 44

Hard technique that are cheap and ‘one off costs’ and are good for city centres where space is limited. However they disperse water quickly and can increase flood risk downstream.

Question 45

What are Levees?

Answer 45

Hard technique that is really expensive and can increase flood risk downstream. However they do allow people to live beside rivers or farms with reduced fears of flooding. 1 mil per km.

Question 46

What is dredging?

Answer 46

Hard technique which increases the capacity of the river, needs to be done every year as channel refills with sediment and concrete lining is expensive to build. It can also increase the flood risk downstream. 50,000 per km.

Question 47

What is a flood water relief channel?

Answer 47

Hard technique which creates more river channels to divert excess water. Protects built up areas but could cause flooding somewhere else. 14m for 1km.

Question 48

What is flood plain retention?

Answer 48

Soft technique where level of flood plains are lowered and they are restored to shrubs and grassland so they can retain water over a period and release it slowly into the river. 1.2 mil for 2km stretch.

Question 49

What is river channel restoration?

Answer 49

Soft techniques where meanders are rebuilt and banks lowered so the park is flooded not a town. People like the natural look. 1.2 million for 2km stretch.