Rivers 🦆

Question 1

What is the source

Answer 1

Where a river begins

Question 2

What is the drainage basin

Answer 2

The area from which water drains into the river

Question 3

What is watershed

Answer 3

An imaginary line that seperates two drainage basins

Question 4

What is a confluence

Answer 4

The point where two rivers join together

Question 5

What is are tributaries

Answer 5

Smaller rivers which join the main river

Question 6

What is the flood plain

Answer 6

Land that floods when a river flows

Question 7

What is the mouth

Answer 7

Where the riverbflows into the sea or a lake

Question 8

What is the river bed

Answer 8

The bottom of a river channel

Question 9

What is the river bank

Answer 9

The side of a river channel

Question 10

What is a channel

Answer 10

Where a river flows

Question 11

What is a river long profile

Answer 11

The long profile shows how a river’s gradient changes as it flows from its source to its mouth

Question 12

What is corrosion

Answer 12

Soluble particles and minerals dissolved into the river

Question 13

What is abrasion

Answer 13

Rocks carried along by the river wear down the river bed and banks

Question 14

What is hydraulic action

Answer 14

The force of the river against the banks eroding the rock

Question 15

What is attrition

Answer 15

Rocks being transported by the river smash together and break into smaller rounder and smoother pieces

Question 16

What is suspension

Answer 16

Fine light material carried in water

Question 17

What is traction

Answer 17

Large boulders and rocks rolled along the river bed

Question 18

What is solution

Answer 18

Minerals dissolved in water and are carried along in solution

Question 19

What is saltation

Answer 19

Small pebbles and stones bounced along the river bed

Question 20

Where is material deposited in a river

Answer 20

Inner bend of a meander, on the floodplain and at the river mouth

Question 21

How is a waterfall formed

Answer 21

1. A river flows across a flat landscape
2. The hard rock does not wear away as fast as the soft rock and so a SMALL STEP DEVELOPS
3. The soft rock continues to erode quickly and a waterfall develops
4. A plunge pool develops at the base of the waterfall
5. And overhang develops as erosion continues behind the waterfall
6. The overhang collapses and the waterfall retreats back upstream creating a GORGE

Question 22

What direction is erosion in the upper course

Answer 22

Vertical

Question 23

What direction is erosion in the middle course

Answer 23

Lateral

Question 24

What is an ox-bow lake

Answer 24

Horse shoe or semi circular area that represents the former course of a meander

Question 25

Why does deposition occur on the inner bend of a meander

Answer 25

Because it is shallower on the inside bend the water moves slower so has less energy as there is more friction. Therefore the river depositis some of its load creating a gentle slip-off slope

Question 26

How is an ox-bow lake formed

Answer 26

1. Erosion and deposition cause a bend in a river to bend into a meander 2. The meander bends more until it becomes a really tight loop 3. When the water is high the river has enough energy to go straight across the loops rather then around it 4. This is called a MEANDER CUT OFF 5. The river keeps to its new channel and so the loop left is called an ox-bow lake

Question 27

How are levees and floodplains formed

Answer 27

1. When a river floods the water leaves the cahnnel and flows onto the floodplain 2. As the water leaves the channel it loses enrgy due to increased friction resulting in deposition 3. The largest load is deposited first anf the raised river banks are known as levees 4. The smaller load is then deposited in size as it flows further away from the channel 5. The subsequent layers of sediment that build up after flooding create the floodplain

Question 28

What are artificial levees

Answer 28

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

Question 29

What is an estuary

Answer 29

The tidal part of a river where freshwater from the river merges with the saltwater from the sea

Question 30

What are deltas

Answer 30

A flat area of sand and silt built out into the sea

Question 31

What are the human causes of flooding

Answer 31

Deforestation Urbanisation Channelisation

Question 32

What are the physical causes of flooding

Answer 32

``` Ice and snow melt Intense rain conditions Impermeable rocks Saturated ground Steep slopes ```

Question 33

How do you calculate discharge and what is it measured in

Answer 33

Discharge (metres cubed/ seconds) = velocity x volume

Question 34

Give examples fo soft engineering to manage floods

Answer 34

``` Floodplain zoning Doing nothing Flood warning system Retention ponds Afforestation ```

Question 35

Give examples of hard engineering to manage floods

Answer 35

Dams Channelisation Levees/embankments Flood relief channels