Rivers & Hydrology

Question 1

What is a drainage basin/ basin

Answer 1

The area that the river and tributaries drain into

Question 2

Where does a river start and end

Answer 2

Starts - at source

Ends - at mouth

Question 3

What is a confluence?

Answer 3

Where two rivers meet

Question 4

What is a tributary?

Answer 4

Where small rivers join main rivers

Question 5

What is it called when two rivers meet

Answer 5

a confluence

Question 6

What is it called when a small river joins a main river?

Answer 6

Tributaries

Question 7

what is watershed?

Answer 7

The area of land that drains to a particular point on a stream

Question 8

What is a delta?

Answer 8

A low-lying plain of landform occurring at the mouth of the river

Question 9

What shape of the valley is at the upper river?

Answer 9

V shaped = steep gradient

Question 10

What does a V shaped valley mean

Answer 10

it has a steep gradient

Question 11

where are rapids and waterfalls normally found

Answer 11

at the upper river

Question 12

What are the 3 parts of a river course?

Answer 12

Upper
Middle
Lower

Question 13

Which part of the river is normally used for sheep farming/ grazing, tourism and dams?

Answer 13

Upper

Question 14

What is erosion like at upper rivers?

Answer 14

lots of vertical erosion

minimal lateral erosion

Question 15

What is erosion like in middle rivers?

Answer 15

Equal amounts of vertical and lateral erosion

Question 16

What is erosion like in lower rivers?

Answer 16

minimal vertical erosion

Lots of lateral erosion

Question 17

What valley shape is in lower rivers?

Answer 17

U-shaped, wide and flat

Question 18

Which part of the river meanders

Answer 18

Middle

Question 19

What is the valley like in the middle of a river course?

Answer 19

Flat valley floor, sloping valley sides

Question 20

What can the middle river course be used for?

Answer 20

fields and crops and animals

Villages and communication lines

Question 21

What can lower river courses be used for?

Answer 21

Intensive farming, industry, towns, cities, ports, built on floodplains

Question 22

Where would you find ox-bow lakes, Levées and Deltas?

Answer 22

At the lower course of a river

Question 23

What are the 3 types of channel?

Answer 23

Straight channels
Braided channels
Meander channels

Question 24

What are the features of a straight channel?

Answer 24

often man made
goes straight
some variation in flow

Question 25

What are some features of a braided channel?

Answer 25

Have multiple channels and islands of sediment between channels river deltas Semi-arid environments

Question 26

What are meander channels?

Answer 26

The bender bits of rivers that occur in the middle/ lower regions of the course

Question 27

What is the River Rhone in south france an example of?

Answer 27

A braided channel - has large delta at mouth - sand and silt deposits caused river to split into 2 distributaries (Grande and Petite Rhone)

Question 28

How do meanders form?

Answer 28

rivers create sediment in alternating bars (riffles) - when low flows in river and low hydraulic radius is enough to encourage deposits Riffles lower hydraulic radius Areas of high friction flow around deposit - creates flow variation - causes side-to-side motion Pools are eroded in deeper riffle

Question 29

What are riffles

Answer 29

Areas of shallow water caused by deposition of coarse sediment

Question 30

What are river pools?

Answer 30

Areas areas of deeper water between riffles. Caused by Coarse pebbles create steeper gradient than eroded pools.

Question 31

Which factors create a channel gradient

Answer 31

Riffles and pools

Question 32

Where do ox-bow lakes form?

Answer 32

In the lower course of a river

Question 33

How do ox bow lakes form

Answer 33

outside bend of river is continuously eroded Neck of meander narrows neck eventually breaks Forms straight channel Deposition continues, causing old meander to seal off

Question 34

What is the riparian area?

Answer 34

the interface between land and a river/ stream

Question 35

What are the 3 river processes?

Answer 35

Erosion Transportation Deposition

Question 36

What is erosion

Answer 36

wearing away/ breaking down of material by an agent (in rivers, this is water)

Question 37

What is transportation?

Answer 37

= movement of eroded material

Question 38

What is deposition?

Answer 38

material drops out of solution – alluvium = the names of the load that is dropped

Question 39

What 4 factors cause erosion?

Answer 39

Hydraulic action Abrasion Corrasion/ Attrition Corrosion

Question 40

What 4 factors cause transportation?

Answer 40

Traction Saltation Suspension Solution

Question 41

How does hydraulic action cause erosion?

Answer 41

force of water removing material from bed and banks

Question 42

how does attrition cause erosion?

Answer 42

Rivers load collides with itself reducing rocks to particles – makes angular rocks more rounded

Question 43

what is saltation?

Answer 43

when small pebbles bounce along the bed with the river flow - a type of transportation

Question 44

what is suspension?

Answer 44

When fine particles (om, silt, clay) are carried in the river flow

Question 45

How does solution cause transportation?

Answer 45

minerals dissolve in the water and are carried in flow (limestone, chalk = examples)

Question 46

Which of the 3 river processes is most likely to change the shape of a river?

Answer 46

deposition

Question 47

which part of the river has most deposition?

Answer 47

Lower course

Question 48

Which part of the river does transportation mainly occur

Answer 48

Middle course

Question 49

Which part of the river does erosion mainly occur?

Answer 49

upper course

Question 50

Name 3 reasons why rivers lose energy

Answer 50

``` Gradient lessens low precipitation/ high evaporation Human abstraction (usage) Beaver dams Overflow into banks ```

Question 51

What does a Hjulstrøm curve show?

Answer 51

it determines whether a river will erode, transport or deposit sediment

Question 52

Which 2 curves make up the Hjulstrøm curve ?

Answer 52

A critical erosion velocity curve A mean settling velocity curve