Rivers

Question 1

What is the long profile

Answer 1

The long profile shows how a river’s gradient (slope) changes from its source (upland) to its mouth (where it meets the sea or a lake). It’s usually steep near the source and flattens towards the mouth.

Question 2

What are the three courses of a river shown on the long profile?

Answer 2

Upper course – steep gradient, vertical erosion

Middle course – gentler gradient, lateral erosion and transportation

Lower course – very gentle gradient, deposition dominates

Question 3

What are key features of the upper course?

Answer 3

V-shaped valleys

Waterfalls

Interlocking spurs

Vertical erosion with hydraulic action and abrasion

Question 4

What is erosion in the context of rivers?

Answer 4

Erosion is the wearing away of the riverbed and banks by natural processes like water flow and sediment movement.

Question 5

Name the four main processes of river erosion.

Answer 5

Hydraulic action, abrasion, attrition, and solution.

Question 6

What is hydraulic action?

Answer 6

The force of water hitting the river banks and bed, breaking rock particles away.

Question 7

What is abrasion (also known as corrasion)?

Answer 7

When rocks and sediment carried by the river scrape and grind against the riverbed and banks, wearing them away.

Question 8

What is attrition?

Answer 8

When rocks and stones carried by the river collide and break into smaller, smoother pieces.

Question 9

What is solution (also called corrosion)?

Answer 9

When soluble minerals in rocks (like limestone) dissolve in the water.

Question 10

Which erosion processes are most effective in the upper course of a river?

Answer 10

Hydraulic action and abrasion, due to high energy and steep gradients.

Question 11

Which erosion process causes rocks to become rounded?

Answer 11

Attrition.

Question 12

What is transportation in rivers?

Answer 12

The movement of sediment (load) by the river as it flows downstream.

Question 13

Name the four main processes of river transportation.

Answer 13

Traction, saltation, suspension, and solution.

Question 14

What is traction?

Answer 14

Large boulders and rocks are rolled along the riverbed by the force of the water.

Question 15

What is saltation?

Answer 15

Small pebbles and stones are bounced along the riverbed.

Question 16

What is suspension?

Answer 16

Fine, light material like silt and clay is carried within the water (suspended load).

Question 17

What is solution (in transport)?

Answer 17

Minerals are dissolved in the water and carried along in solution – invisible transport.

Question 18

What is deposition in rivers?

Answer 18

Deposition is when a river drops the sediment (load) it is carrying because it no longer has enough energy to transport it.

Question 19

When does deposition occur in a river?

Answer 19

When the river loses energy – this can happen when it slows down, enters a flat area, or the volume of water decreases.

Question 20

Where in a river’s course is deposition most likely to occur?

Answer 20

In the lower course, on the inside bends of meanders, or where a river enters a lake or sea (forming a delta).

Question 21

Where are waterfalls typically found?

Answer 21

Waterfalls are often found in the upper course of rivers where there is a sudden change in the landscape, such as along the edge of a resistant rock layer.

Question 22

What are the stages of waterfall formation?

Answer 22

Initial erosion: Water flows over resistant rock.

Undercutting: The softer rock below is eroded faster, creating a step.

Overhang formation: The harder rock forms an overhang as the soft rock is eroded away.

Collapse: The overhanging rock eventually collapses due to gravity.

Retreat: The waterfall retreats upstream as erosion continues.

Question 23

What is a plunge pool?

Answer 23

A plunge pool is a deep, rounded depression at the base of a waterfall, formed by the erosive action of water and falling debris.

Question 24

What feature forms behind a waterfall over time?

Answer 24

A gorge, which is the deep, steep-sided valley left behind as the waterfall retreats upstream.

Question 25

What is a meander?

Answer 25

A meander is a large, looping bend in the river’s course, typically found in the middle and lower course of a river.

Question 26

How is a meander formed?

Answer 26

A meander is formed through the process of lateral erosion, where the river erodes its banks, causing it to curve and form a bend.

Question 27

What happens on the outside bend of a meander?

Answer 27

The outside bend has faster-flowing water, which causes more erosion and undercuts the bank, creating a steep riverbank.

Question 28

Order of meander and ox box formation

Answer 28

Initial Stage: In the river’s middle and lower course, the water flows slowly, allowing lateral (sideways) erosion to take place. Erosion on Outside Bend: The river erodes the outer bank of a curve more quickly because the water flows faster there. This forms a steep riverbank. Deposition on Inside Bend: On the inner bend, water flows more slowly, leading to the deposition of sediment, forming a gently sloping bank known as a point bar. The neck of land between two adjacent meanders becomes narrower as erosion continues on both sides of the river. During a flood or period of high flow, the river may cut through the narrow neck of land, creating a straight channel. This action isolates the loop from the main flow of the river.

Question 29

What is a floodplain?

Answer 29

A floodplain is a flat area of land next to a river, formed by the deposition of sediment over time, particularly during floods.

Question 30

What is an estuary?

Answer 30

An estuary is a tidal area where a river meets the sea, characterized by brackish water and a mix of fresh and saltwater.

Question 31

What is a levee?

Answer 31

A: A levee is a natural or artificial embankment along the riverbank designed to prevent flooding.

Question 32

How is a levee formed?

Answer 32

Deposition During Flooding: When a river overflows its banks during a flood, the sediment carried by the river is deposited closest to the bank, forming a raised area. Layering of Sediment: Over time, repeated flooding and deposition create a series of levees along the riverbanks.

Question 33

What type of landforms can be found along the River Tees?

Answer 33

The River Tees features several landforms, including: Waterfalls (e.g., High Force Waterfall). Meanders and oxbow lakes in its middle course. Floodplains and levees in its lower course. Estuary at Teesmouth where the river meets the sea.

Question 34

How was High Force Waterfall formed on the River Tees?

Answer 34

High Force is formed where the river flows over hard, resistant rock (limestone) over softer rock (sandstone). The softer rock erodes faster, creating a drop, while the hard rock overhangs, creating the waterfall.

Question 35

What is significant about Teesmouth?

Answer 35

Teesmouth is an important estuary, with significant industrial and port activity. The area also contains valuable wildlife habitats, including salt marshes and mudflats.

Question 36

Where is High Force Waterfall located?

Answer 36

High Force is located in Teesdale, County Durham, in the Pennines. It’s one of the largest waterfalls in England.