11.2 The long profile of a river

Question 1

what is a long profile

Answer 1

a line representing the river from source to mouth

Question 2

how long is the River Severn

Answer 2

354 km (longest in the UK)

Question 3

describe the course of the River Severn

Answer 3

• rises to the height of 610 metres in the Cambrian mountains
• travels eastwards across the English-Welsh border and reaches the Norman town of Shrewsbury (in the country of shropshire)
• it then continues its course south through the counties of Worcestershire and Gloucestershire
• the mouth of the river opens up to the Bristol channel

Question 4

What happens to depth and width downstream

Answer 4

depth and width increases downstream due to erosion (hydraulic action and abrasion)

Question 5

What happens to velocity downstream

Answer 5

velocity increases because there is less friction with the bed, bank and vegetation

Question 6

What happens to discharge downstream

Answer 6

the discharge increases as tributaries join the main channel

Question 7

What happens to bed load downstream

Answer 7

Decreases in size due to erosion, especially attrition and abrasion

Question 8

What does the gradient do downstream

Answer 8

Decreases because the river has to get from the highest point (the source) to the lowest point (the mouth)

Question 9

Describe how discharge and gradient change downstream (4 marks)

Answer 9

• as you travel downstream the discharge (amount of water at a given point in a river increases)
• this is due to channel widening and deepening by erosion and the joining of tributaries to the main river channel
• the gradient decreases as you travel from the upper to the middle and lower course
• this is due to the source being in an upland area and the mouth being on gently sloping or flat land when it opens to sea
• the change in geology can also influence gradient (softer rock in the middle and lower course)