3. Drainage Basin & Floodplains

Question 1

What is a Drainage Basin

Answer 1

An area that has been dried by a river and its tributaries

Question 2

What is the Source

Answer 2

The area in which a river begins (usually in the mountains/at a high altitude)

Question 3

What is the Mouth

Answer 3

Where a river ends it’s journey flowing into the sea or a lake

Question 4

What is a tributary

Answer 4

A smaller river that joins a larger river

Question 5

What is a Confluence

Answer 5

The point at which 2 rivers join

Question 6

What is a Watershed

Answer 6

The boundary between 2 drainage basin marked by a ridge of high land

Question 7

What happens mostly in the Upper Course of a river

Answer 7

Erosion

Question 8

What Landforms are present in the upper course

Answer 8

Waterfalls and Plunge Pools
V-Shaped Valleys
Interlocking Spurs

Question 9

What happens at the Middle Course of a river

Answer 9

Transportation

Question 10

What Landforms occur at the Middle Course of a river

Answer 10

Meanders

Question 11

What happens mostly in the Lower Course of a river

Answer 11

Deposition

Question 12

What Landforms occur in the Lower Course

Answer 12

Ox-Bow Lakes
Flood plains
Levees

Question 13

Hydraulic Action

Answer 13

This process involves the force of water against the river bed & banks

Question 14

Abrasion

Answer 14

This is the process by which the bed & banks are worn down by the rivers load

Question 15

Attrition

Answer 15

The load carried by the river bump into each other & are smoothed & broken down into smaller particles

Question 16

Corrosion

Answer 16

This is the chemical action of a river water. The acids in the water slowly dissolve the bed & banks

Question 17

Traction

Answer 17

Boulders & pebbles are rolled along the river bed at times of high discharge

Question 18

Saltation

Answer 18

Sand sized particles are bounced along the river bed by the flow of water

Question 19

Suspension

Answer 19

Fine clay & sand particles are carried along within the water even at low discharges

Question 20

Solution

Answer 20

Some minerals dissolve in water such as calcium carbonate. This requires very little energy

Question 21

Where does erosion occur in a river (inside or outside the bend)

Answer 21

Outer bend

Question 22

Where does deposition occur in a river (inside or outside the bend)

Answer 22

Inner bend

Question 23

What are some Physical causes of flooding

Answer 23

Heavy rainfall
Prolonged rainfall e.g monsoon
Melting of snow/glacier

Question 24

What are some Human causes of flooding

Answer 24

Deforestation
Urbanisation
Narrowing a river channel e.g bridge
Building of leveés/embankments

Question 25

What are some Positive impacts of flooding for People

Answer 25

Replenishes drinking water supplies especially wells
Provides sediment/silt/alluvium that fertilises the soil
Can encourage innovative solutions to flooding e.g houses on stilts

Question 26

What are some Negative impacts of flooding for People

Answer 26

Spreads waterborne diseases e.g cholera
People & animals can drown or become homeless
Crops grown on fertile flood plains can be washed away

Question 27

What are some Positive impacts of flooding for the Environment

Answer 27

Fish can breed in standing water

In dry areas, flooding can relieve an area from drought

Question 28

What are some Negative impacts of flooding for the Environment

Answer 28

Flooding can wash chemical or sewage into local rivers & pollute them
Wild animals may drown or lose their habitat

Question 29

What are some Hard Engineering methods

Answer 29

Widen/Deepen Channel

Straighten/Concrete Channel

Question 30

What are some Soft Engineering methods

Answer 30

Afforestation- planting trees
Washlands- waste land that does not matter if flooded
Land use zoning

Question 31

What is Hard Engineering

Answer 31

Artificial features to control the river, these methods are not sustainable in the long term

Question 32

What is Soft Engineering

Answer 32

They are more sustainable than Hard Engineering methods