Rivers, 10

Question 1

Source of the river is…

Answer 1

Where a river begins.

Question 2

Drainage of the river is…

Answer 2

The area from which water drains into the river.

Question 3

Watershed of the river is…

Answer 3

An imaginary line that separates two drainage basins.

Question 4

Confluence of the river is…

Answer 4

The point where two rivers join together.

Question 5

Tributaries of the river is…

Answer 5

Smaller rivers which joins the main river.

Question 6

Flood plain of the river is…

Answer 6

Land that floods when a river overflows.

Question 7

Mouth of the river is…

Answer 7

Where a river flows into the sea or lake.

Question 8

River Bad of the river is…

Answer 8

The bottom of a river channel.

Question 9

River Bank of the river is…

Answer 9

The side of a river channel.

Question 10

Channel of the river is…

Answer 10

River flow in this

Question 11

The middle Course of the river is….

Answer 11

In the middle course, the river starts to flow slowly because it starts to transport lots of sediment, as rivers look muddy. As a river mover down its valley, a number of changes occur. The river gets wider, as more tributaries join together.

• the valley sides become less steep, giving the shape of a open V.
• the river begins to erode sideways, into its banks. This opens out the valley floor and a flood plain that starts to develop.
• erosion and deposition occur.
• the edges of the floodplain are market bluffs.

Question 11

The upper Course of the river is…

Answer 11

The steepest part of land in the river. It is usually small, but flows quickly. The energy levels are high and the river cuts away at its bed. As it does it quickly deepens its valley. Downward erosion is the dominant process. ( velocity of river is slowest in the upper course)

Question 12

Erosion is…

Answer 12

The gradual removal of rocks from a river’s banks and bed.

Question 13

Abrasion/Corrasion

Answer 13

Rocks carried along by the river wear down the river bed and banks. The river is using the load it is carrying like sand paper to wear down its bed and banks.

Question 14

Hydraulic action

Answer 14

The force of the river against the banks can cause air to be trapped in cracks and crevices. The pressure builds, weakening the bed and banks and gradually wearing them away.

Question 15

Solution / Corrosion

Answer 15

Soluble particles and minerals are dissolved into the river. ( Similar or sugar granules dissolving in tea or coffee)

Question 16

Attrition

Answer 16

Rocks being transported by the river smash together and break into smaller, rounder and smoother pieces. ( these same rocks are responsible for abrasion )

Question 17

River landforms, upper course: V-shaped valleys

Answer 17

The river erodes downwards as boulders, stones and rock particles are bounced and scraped along the channel bed.

As the river cuts down, the steep sides are attacked by weathering. This breaks up and loosens the soil and rock.

The loosened material slowly creeps down the slope because of gravity or is washed into the river by the rainwater. The river carries it away.

The end result is a speed sided valley that has the shape of a letter “V”

Question 18

Four main factors affect the rate of river erosion.

Answer 18

1. Gradient - a steep gradient results in the river water being pulled by gravity, cutting down and eroding the channel.
2. Rock resistance - erosion rate increases more erodible the rock - for example limestone is easily eroded - harder rocks such has igneous rock are difficult to erode.
3. Velocity - erosion rate increases as velocity increases - more load can be carried and therefore more erosion occurs.
4. Discharge- erosion increases is discharge Increases. The water in a river the more power it has.

Question 20

Meander is…
It is formed by…

Answer 20

Band in the flow of the river.
It is formed by abrasion.

Question 21

Ox-bow lake…

Answer 21

A horseshoe or semi-circular area that represents the former cause of a meander.
! River meander are formed by lateral erosion!

Question 22

Formation of ox-bow lake + meander

Answer 22

1. A meander starts as a slight bend. Water flows faster on the outside of the bend that on inside.
2. So the outside of the bend is eroded away. Material is deposited on the inside of the bend.
3. This erosion and deposition turns in the bend into a meander.
4. The meander bends more and over the years until it becomes a really tight loop.
5. When the water level is really high, the river has enough energy to go straight across the loop, rather than round it.
6. This is called a meander cut-off.
7. The river keeps to its new channel, so the loop is left as an ox-bow lake.
8. After a long time, the ox-bow lake slits up and dries out, and plants grow in it.

Question 23

Floodplain is…

Answer 23

The area of flat land adjacent to the river channel in the lower course. Created to allow water to overflow once bank full conditions are reached.

Question 24

Artificial levees…

Answer 24

Created as a flood defence they increase the maximum volume of water the channel can take and so reduce the likelihood of flooding.

Question 25

Estuaries…..

Answer 25

An estuary is the tidal part of a river where freshwater from the river merges with saltwater from the sea.

Question 26

Causes of flooding:

Answer 26

1. Physical cause
   ( heavy rain, steep slopes)
2. Human cause
   ( urbanisation, channelisation, deforestation)

Question 27

Peak discharge…

Answer 27

The highest recorded discharge following a rainfall event ( the top of the line graph)

Question 28

Peak rainfall…

Answer 28

The highest amount of rainfall per time unit

Question 29

Lag time….

Answer 29

The time difference between peak discharge.

Question 30

2 methods of hard engineering:

Answer 30

Dams and reservoirs, channel straightening.

Question 31

Подивитися у книгу

Answer 31

Там відповіді + багато повтореного матеріалу

Question 32

Coastline

Answer 32

A place which land meets the sea

Question 33

Weathering

Answer 33

Weathering is the breakdown of rocks at the Earth’s surface, by the action of rainwater, extremes of temperature, and biological activity.

Weathering = physical, chemical, biological

Question 34

Weathering, biological

Answer 34

• roots from plants are incredibly strong.
• in the rocks can be found the smallest cracks and weakness.
• once in this gaps can begin to expand, so the rock can became weaker.
• this can lead to pieces falling off and therefore weathering.
• animals burrowing and walking over the surface, this is too causing.

Question 35

Weathering, physical

Answer 35

• the wind can blow tiny grains of sand against a rock.
• these wear the rock away and weather it.
• rain can break the rock, but need to over long time.
  -ice can also break the rock , by the freezes, it expands and pushes the crack further apart.
• when the ice melts, water can get further into the crack.
• when rock freezes again, it expands and makes the crack even bigger.

Question 36

Weathering, chemical

Answer 36

• chemical reaction break down the bonds holding the rocks together.
• it causing to fall apart, forming smaller and smaller pieces.

Question 37

Mass movements

Answer 37

Is the downslope movement of rock soil or mud under the influence of gravity.
1. Rock falls
2. Slumping
3. Mud slides