Understanding Our Natural World: River Environments

Question 1

The Drainage Basin

4 marks

Answer 1

Area of land that is drained by a river and its tributaries. When a droplet of water falls onto the land (as precipitation), gravity will make sure that the water is pulled downhill to the sea.

Question 2

When a droplet of water falls onto the land (as precipitation)

(2 marks)

Answer 2

Gravity will make sure that the water is pulled downhill to the sea.

Question 3

The Water Cycle (Hydrological Cycle) - simplified

4 marks

Answer 3

Water is recycled through the process of; evaporation, condensation and water transfers such as surface runoff.

Question 4

Amount of the worlds water contained within oceans and seas.

1 mark

Answer 4

97% of the worlds water is found in oceans/seas.

Question 5

Amount of the world’s water found in ice.

1 mark

Answer 5

Ice holds 2% of the world’s water.

Question 6

Amount of the world’s water found on land and in the atmosphere (air)

(1 mark)

Answer 6

1% of the world’s water is found on land and in the atmosphere.

Question 7

The Water Cycle (in order)

10 marks

Answer 7

• Evaporation
• Water vapour is blown over the land
• Evapotranspiration; air rises, cools and condenses
• Precipitation
• Surface runoff/overland flow
• Infiltration
• Percolation and throughflow
• Groundwater flow

Question 8

Major Component of the Water Cycle

1 mark

Answer 8

Drainage Basin System

Question 9

Interrelationships within the Drainage Basin System

17 marks

Answer 9

Inputs: Precipitation

Store: Surface storage, Interception, Soil moisture

Transfer: Stemflow, Infiltration, Percolation , Channel flow, Surface runoff, Throughflow, Groundwater flow

Output: Evapotranspiration, River discharge

Question 10

Inputs of Drainage Basin System

2 marks

Answer 10

How water is introduced into the Drainage Basin System - Precipitation.

Question 11

Inputs of Drainage Basin System (Simplified)

1 mark

Answer 11

Precipitation

Question 12

Stores of Drainage Basin System

7 marks

Answer 12

How water is stored or held for a period of time within the DB System - Interception (by vegetation), Soil Moisture, Surface Storage (lakes), Groundwater storage

Question 13

Transfers of Drainage Basin System (Simplified)

7 marks

Answer 13

Stemflow, Infiltration, Percolation , Channel flow, Surface runoff, Throughflow, Groundwater flow

Question 14

Transfers of Drainage Basin System

8 marks

Answer 14

A process or flow of water from one place to another in the DB System - Stemflow, Infiltration, Percolation , Channel flow, Surface runoff, Throughflow, Groundwater flow

Question 15

Outputs of Drainage Basin System (Simplified)

2 marks

Answer 15

Evapotranspiration, River Discharge

Question 16

Outputs of Drainage Basin System

4 marks

Answer 16

How the water is released either back to the sea or back into the atmosphere -
Evapotranspiration, River discharge

Question 17

How does a river change course downstream?

2 marks

Answer 17

A river changes shape as it flows from its Source to its Mouth.

Question 18

Long Profiles are made up of

12 marks

Answer 18

• Source
• Upper part of River - has larger bedload, more roughness, turbulence & friction.
• Watershed
• Lower part of River - has greatest cross-section, highest hydraulic radius, greatest velocity & discharge.
• Mouth

Question 19

The Source of a River

3 marks

Answer 19

Is often, but not always, in an upland area.

Near the source, a river flows over steep slopes with uneven surfaces.

Question 20

Near the River’s Source

4 marks

Answer 20

• River flows over steep slopes with uneven surfaces. Often moving over a series of waterfalls and rapids.
• There is more Vertical Erosion here as the river flows downhill, using its energy to overcome friction.

Question 21

Vertical Erosion

3 marks

Answer 21

Occurs as a river flows down steep slopes, cutting down towards the river bed and carving out steep-sided V-shapes valleys.

Question 22

As the river approaches the mouth

7 marks

Answer 22

• Gradient of the slope becomes less steep, flowing over flat land as it approaches the sea.
• Velocity and energy increase due to increased discharge
• Performs more Lateral Erosion making the Channel wider/smoother meaning less turbulence and friction.

Question 23

As the river approaches the mouth more Lateral Erosion takes place.
What does that mean for the Channel?

(3 marks)

Answer 23

Makes the Channel wider/smoother meaning less turbulence and friction making water flow more efficient.

Question 24

As the river moves from the source to the mouth

1 mark

Answer 24

Both the depth and width of the river increase.

Question 25

When does the load of a river change?

2 marks

Answer 25

As it is transported and eroded along the river’s profile.

Question 26

Result of the Transportation and Erosion of a Rivers Load (along the river’s profile).

(1 mark)

Answer 26

Size and shape of stones will change as as they journey through the river profile.

Question 27

River Discharge increases when

1 mark

Answer 27

As the river approaches the sea.

Question 28

River Discharge Calculation

3 marks

Answer 28

Usually calculated as the cross-sectional area (depth x width) multiplied by the velocity or speed of the water.

Question 29

Cross Profiles

2 marks

Answer 29

Shows a cross-section of a River’s Channel and Valley at a certain point along the rivers course.

Question 30

As a result of Vertical Erosion near the Source of a river

3 marks

Answer 30

Channels are narrow and shallow and may contain large boulders + angular fragments eroded/weathered from the steep valley sides.

Question 31

The Sediment in the River

1 mark

Answer 31

Creates turbulence and friction.