Rivers

Question 1

Define Percolation

(Hydrological Cycle)

Answer 1

The ability for rocks to allow water to flow through them

Question 2

Define Drainage Basin

Answer 2

An area which is drained by a river and its tributaries.

Question 3

Define Bedload

Answer 3

The river’s load which is dragged along the bed.

Question 4

Describe the cross-profile and features of a river’s upper course.

Answer 4

Profile: V-Shaped (v. narrow)
Features: e.g. Waterfalls (+ gorges), Water rapids, steep gradient.

Question 5

Describe the cross-profile and features of a river’s middle course.

Answer 5

Profile: U-Shaped (wide + deep)
Features: e.g. Ox-bow lakes, Meanders, Tributaries

Question 6

Describe the cross-profile and features of a river’s lower course.

Answer 6

Profile: u-Shaped (wide but shallower)
Features: e.g. Deltas, sand-banks, flood plains, v. gentle gradient

Question 7

Define Solution

(erosion)

Answer 7

The dissolving of certain types of rocks (chalk + limestone) by rainwater

Question 8

Define Attrition

Answer 8

When the river’s load collides with each other and break up.

Question 9

Define Abrasion

Answer 9

When the load scrapes against the bed (most common form of erosion)

Question 10

Define Hydraulic Action

Answer 10

Erosion caused by the sheer force hitting the bed and banks

Question 11

Define Solution

(transportation)

Answer 11

Transportation of minerals dissolved in the water (chemical change)

Question 12

Define Saltation

Answer 12

When small stones bounce along the bed

(they are light enough to be lifted, but too heavy to be held.)

Question 13

Define Suspension

Answer 13

When finer sediment (e.g. sand) is carried within the water

(this often makes the water look muddier)

Question 14

Define Traction

Answer 14

When larger stones and boulders are rolled along the river bed

(too heavy to be lifted by the water)

Question 15

What causes deposition to occur?

Answer 15

When the river’s velocity decreases and it no longer has the power to carry the sediment.
For example, this can be due to a reduced gradient, increased load, or the river reaching the sea.

Question 16

What happens if there is increased sediment in the river?

Answer 16

The river loses velocity and so more sediment is deposited or transported by traction and saltation.

Question 17

How are waterfalls formed?

Answer 17

Soft rock under a band of hard rock is eroded faster, which creates a step. This grows over time until the hard rock is undercut and collapses under its own weight.

(This also causes the waterfall to retreat over time.)

Question 18

What is left as a waterfall retreats?

Answer 18

A steep-sided gorge

Question 19

What are interlocking hills called when a river zig-zags between them?

(Taken from cgp book as bonus)

Answer 19

Interlocking Spurs

Question 20

How do meanders form?

Answer 20

Bends form through the erosion on the outside (river-cliff) and deposition on the inside (slip-off slope).

Question 21

Define Meander Scar

Answer 21

An ox-bow lake (formed by a conjoined meander) that has dried up.

Question 22

What form of erosion occurs mainly in the upper course?

Answer 22

Vertical erosion (deepening the river)

Question 23

How long is the River Tees?

Answer 23

137km

Question 24

Where is the River Tees’ source?

Answer 24

Cross Fell in the Pennines

Question 25

What can cause flooding?

Answer 25

Long, prolonged rainfall. Steep relief + rainfall. Melted snow. Urbanisation (bad drainage).

Question 26

What is a hydrograph?

Answer 26

Hydrographs show the relationship between rainfall and river discharge over time.

Question 27

What is steep relief?

Answer 27

A landscape characterized by significant and abrupt changes in elevation or height.

Question 28

What is hard engineering?

Answer 28

Using artificial structures to try to control river processes (dams, embankments, locks, river straightening, flood relief channels).

Question 29

What are some erosional landforms found along the River Tees?

Answer 29

High Force waterfall. V-Shaped valleys. Interlocking spurs. Gorges.

Question 30

How are interlocking spurs formed?

Answer 30

As the river erodes downwards, the spurs of land between the valley sides are left standing.

Question 31

What is soft engineering?

Answer 31

Working with natural processes to reduce the risk of flooding (afforestation, flood warnings, land use zoning, flood storage areas).

Question 32

What caused the Boscastle flood?

Answer 32

Saturated ground due to above average rainfall. At confluence of three rivers. Very steep drainage basin. Mostly impermeable geography.

Question 33

What happened in the Boscastle flood?

Answer 33

Extremely high discharge in the river in a short amount of time flooded the village.

Question 34

What were some impacts of the Boscastle flood?

Answer 34

Many homes and businesses were damaged. Cars were swept away.

Question 35

What were some responses to the Boscastle flood?

Answer 35

£10 million was spent on a new flood defense scheme, completed in 2008, to reduce the risk of this happening again. Low bridges were replaced with wider and taller bridges.

Question 36

What hard management techniques were employed in response to the Boscastle flood?

Answer 36

The river was deepened and widened to increase it's capacity.

Question 37

What soft management techniques were employed in response to the Boscastle flood?

Answer 37

Land owners were encouraged to plant more trees.

Question 38

When did the Boscastle flood occur?

Answer 38

16th August 2004

Question 39

What are the pros of soft management techniques?

Answer 39

Cheaper than hard management techniques. Won't affect fluvial processes. Sustainable and environmentally friendly. Low maintenance solutions.

Question 40

What are the cons of soft management techniques?

Answer 40

Not always reliable or effective. Often doesn't reduce the level of flooding. May not be suitable in all areas. Limited use in urban areas. Can impact agricultural land.

Question 41

What are the pros of hard management techniques?

Answer 41

Controls the level of flooding. Dams can produce hydroelectric power. Can help improve navigation for boats. Can be used to store water. Protects properties from flooding.

Question 42

What are the cons of hard management techniques?

Answer 42

More expensive than soft management. Can harm fluvial processes downstream (increased erosion, deposition, and flood risk). Can cause habitat loss.

Question 43

What does river straightening do?

Answer 43

By removing bends and meanders, and widening and deepening the channel, water flow and channel capacity can be increased, reducing flood risk.

Question 44

What do embankments do?

Answer 44

By artificially raising the river banks, it reduces the risk of the river breaking its banks, lowering flood risk.

Question 45

What do flood relief channels do?

Answer 45

By building artificial channels parallel to the river, excess water can be diverted during high flow periods, reducing flood risk.

Question 46

What does afforestation do?

Answer 46

By planting trees along riverbanks, the riverbanks can be stabilised, reducing flood risk.

Question 47

What does flood plain zoning do?

Answer 47

By regulating development in areas prone to flooding, potential damage from flooding can be reduced.