River processes and landscapes

Question 1

Name some drainage basin flows

Answer 1

• evaporation
• transpiration
• inflitration
• throughflow
• overland flow/surface run-off

Question 2

Describe infiltration

Answer 2

when water soaks down into the soil

Question 3

Describe throughflow

Answer 3

once in the soil, water flows slowly below the ground until it reaches a river/lake

Question 4

Describe surface run-off

Answer 4

water flowing quickly downslope over the ground towards rivers

Question 5

Which flow do you think makes the most important contribution to the risk of flooding and why?

Answer 5

surface run-off

as the water is travelling on the surface of the ground, it is a lot faster

Question 6

Name some drainage basin stores

Answer 6

• Interception storage
• Soil storage
• Groundwater storage

Question 7

Describe interception storage

Answer 7

plant leaves are a temporary storage space where water sits for a time, until it evaporates or drips to the ground

Question 8

Describe soil storage

Answer 8

water can be held in the soil for a while

Question 9

Describe groundwater storage

Answer 9

water is held in solid rock or gravels beneath the soil

Question 10

Describe erosion

Answer 10

breakdown and removal of sediment

vertically in the upper course
laterally in the middle/lower course

Question 11

Describe transport

Answer 11

the movement of material by the river

Question 12

Describe deposition

Answer 12

the laying down of material due to loss of river energy

Question 13

How are waterfalls/gorges formed

Answer 13

Formed in the upper and middle course of the river where there are different rock types.

The river flows over the hard rock edge and down into the soft rock where it erodes it to form a plunge pool

Over time, the soft rock erodes backwards, forming a hard rock overhang. The overhang eventually collapses, causing the waterfall to retreat backwards

It leaves behind a steep sided narrow bottomed valley called a gorge

Question 14

How are meanders formed

Answer 14

Found in the lower course of a river.
They are bends in the river caused by lateral erosion.

Deposition occurs on the inside bend of the river, forming a slip-off clope

Erosion occurs on the ouside bend as the flow is much faster

Continued erosion and deposition causes the meander to move across the river floodplain

Question 15

Define abrasion

Answer 15

when rocks carried by the river smash into the banks/bed of the river

Question 16

Define attrition

Answer 16

when rocks crash together

Question 17

Define hydraulic action

Answer 17

when air is forced into cracks in the banks of a river, forcing them to expand

Question 18

Define solution

Answer 18

where chemicals in the river dissolve minerals

Question 19

Define suspension

Answer 19

when fine particles float in the river flow

Question 20

Define saltation

Answer 20

where rocks bounce along the riverbed

Question 21

Define traction

Answer 21

when boulders roll over smaller rocks on the riverbed

Question 22

How are V-shaped valleys formed?

Answer 22

Found in the upper course of a river
Most of the erosion is vertical.
They have steep sides + narrow valley floor.

Question 23

Name some physical causes of flooding

Answer 23

• Geology (impermeable rocks)
• Vegetation
• Climate patterns

Question 24

Name some human causes of flooding

Answer 24

• Urbanisation
• Changes to ecosystem (deforestation)

Question 25

Give an example of hard engineering strategy that helps with flood risk management

Answer 25

River engineering * widening/deepening the river channel - allows for larger capacity of water * gives more time until bank full

Question 26

Give an example of soft engineering strategy that helps with flood risk management

Answer 26

Planting more vegetation * allows for more interception

Question 27

Define mouth in the context of rivers

Answer 27

where the river meets the sea/lake

Question 28

Define watershed in the context of rivers

Answer 28

where the water falls into 2 different drainage basins

Question 29

Define confluence in the context of rivers

Answer 29

where 2 rivers meet

Question 30

Define tributary in the context of rivers

Answer 30

a small stream that joins the main river

Question 31

Define source in the context of rivers

Answer 31

where the river starts

Question 32

Define catchment area in the context of rivers

Answer 32

the drainage basin

Question 33

How are oxbow lakes formed?

Answer 33

Due to continued depostion and erosion, a meander becomes more pronounced. Eventually, the river breaks through the neck of the meander, and the river flows in a straight line. The old meander is left behind as an oxbow lake.

Question 34

Define what an estuary is and its location

Answer 34

a link between the ocean and the land where salty marine water mix with freshwater.

Question 35

Why are estuaries important features?

Answer 35

* act as storm buffers to prevent flooding * ideal breeding grounds for fish

Question 36

Why are estuaries under threat from human activity?

Answer 36

man-made structures can affect the passage of water + conditions in an estuary