long and changing cross profile

Question 1

What is the long profile?

Answer 1

A line representing the course of the river from its source (relatively high up) to its mouth where it ends, usually in a lake or the sea, and the changes in height along its course

Question 2

What is the shape of the long profile of a river?

Answer 2

The steep reduction in height near the source gives way to a more gradual reduction further downstream, giving a typical concave profile

Question 3

What happens to the potential energy of the river’s water through this long profile?

Answer 3

The river has much potential energy near the source due to the steep drop. Later on, this is replaced by energy from a large volume of water

Question 4

Why is such a perfect long profile rare?

Answer 4

Because the land is being uplifted, sea level changing and bands of hard and soft rock crossing the path of the river

Question 5

What is the cross profile?

Answer 5

A line that represents what it would be like to walk from one side of a valley, across the channel and up the other side

Question 6

What happens to a river’s cross profile as it flows downstream?

Answer 6

It’s valley changes shape. Generally, the cross profile shows the valley becoming wider and flatter, with lower valley sides

Question 7

How is the channel shaped near the source of a river?

Answer 7

It is shallow and narrow

Question 8

What direction is erosion happening in near the source?

Answer 8

Vertically

Question 9

What are the main types of erosion near the source?

Answer 9

Hydraulic action, abrasion, and attrition

Question 10

What types of transportation are happening near to the source of a river?

Answer 10

Some traction and saltation at high flow

Question 11

Which material is being deposited in the upper course?

Answer 11

Large material

Question 12

What size is the load near the source?

Answer 12

Large

Question 13

How is the channel shaped in the middle course?

Answer 13

It is wider and deeper (than the upper course)

Question 14

What direction is erosion happening in the middle course?

Answer 14

There is some vertical erosion; but lateral erosion is more important

Question 15

What erosion is taking place in the middle course?

Answer 15

Hydraulic action is less important

Question 16

What types of transportation are happening in the middle course?

Answer 16

Suspension is the main type of transportation; saltation and traction are still present

Question 17

What is happening with deposition in the middle course?

Answer 17

Deposition is more obvious

Question 18

What size is the load in the middle course?

Answer 18

The load size is reduced (compared to the upper course)

Question 19

How is the channel shaped in the lower course?

Answer 19

It has the widest and deepest channel

Question 20

What direction is erosion happening near the mouth of the river?

Answer 20

There is less erosion; only a little lateral

Question 21

What are the main types of erosion near the mouth?

Answer 21

All erosion is much less important

Question 22

What type of transportation is happening in the lower course?

Answer 22

Suspension is dominant

Question 23

Which material is being deposited near the mouth of a river?

Answer 23

There is the deposition of fine material

Question 24

What size is the load in the lower course?

Answer 24

There is a large amount of load, but its size is now very small