River Processes

Question 1

Define a Drainage Basin

Answer 1

The area of land around the river that is drained by the river and its tributaries

Question 2

Define a tributary

Answer 2

A small river or stream that joins a larger river

Question 3

Define a mouth

Answer 3

Where a river meets the sea

Question 4

Define a source

Answer 4

Where a river begins

Question 5

Define confluence

Answer 5

The point at which two rivers meet

Question 6

Define a channel

Answer 6

Where the river flows

Question 7

Define a watershed

Answer 7

The area of high land forming the edge of a river basin

Question 8

What is a long profile of a river?

Answer 8

A long profile shows how the river changes over its course to its mouth

Question 9

What is an upper course of a river?

Answer 9

Where the river starts and is usually an upland area. The river’s load is large in the upper course, as it hasn’t been broken down by erosion yet.

Question 10

What is the lower course of a river?

Answer 10

The final course of the river is where the land is a lot flatter. The river’s load is fine sediment, as erosion has broken down the rocks.

Question 11

What is a cross profile?

Answer 11

A view of the valley from one side to another.

Question 12

What happens when the river flows downhill?

Answer 12

There is an increase in vertical erosion, the channel is shallow and narrow because there is not a lot of water in the channel.

Question 13

What happens when the river flows into the middle course?

Answer 13

There is some vertical erosion but more lateral erosion, the channel is wider and deeper as a result.

Question 14

What happens in the lower course of a river?

Answer 14

There is a lot less erosion and greater influence of deposition, with only some lateral erosion. The channel is at its widest and deepest.

Question 15

What are the four types of erosion?

Answer 15

Hydraulic action, abrasion, attrition and solution

Question 16

Define hydraulic action

Answer 16

This is the sheer power of the water as it smashes against the river banks. Air becomes trapped in the cracks in the rock of the river bank and bed, and causes the rock to break apart.

Question 17

Define abrasion

Answer 17

When pebbles are picked up by the flowing water and smash against the river bank and bed, wearing it away.

Question 18

Define attrition

Answer 18

When rocks that the river is carrying knock against each other. They break apart to become smaller and more rounded.

Question 19

Define solution

Answer 19

When the water dissolves certain types of rock, eg limestone.

Question 20

What are the four types of transportation?

Answer 20

Traction, saltation, suspension and solution.

Question 21

Define traction

Answer 21

Large, heavy pebbles are rolled along the river bed.

Question 22

Define saltation

Answer 22

Pebbles are bounced along the river bed, most commonly near the source.

Question 23

Define suspension

Answer 23

Lighter sediment is suspended within the water, most commonly near the mouth of the river.

Question 24

Define solution

Answer 24

The transport of dissolved chemicals. This varies along the river depending on the presence of soluble rocks.

Question 25

What is deposition?

Answer 25

When the river loses energy, it drops any of the material it has been carrying.

Question 26

What factors lead to deposition?

Answer 26

• shallow water
• at the end of the river’s journey, at the river’s mouth
• when the volume of water decreases