4.6

Question 1

What is meant by the long profile of a river?

Answer 1

The long profile of a river shows changes in the height (altitude) of the course of a river from its source to its mouth.

Question 2

How does the river Eden’s landscape change along its long profile
(upper/middle/lower). Consider: channel shape, valley profile, gradient,
discharge, velocity and sediment size and shape?

Answer 2

In the upper course of the river it is steep with large sediment its river channel is narrow and a lot of vertical erosion happens here.

In the middle course of the river has more energy and a high volume of water. The gradient here is gentle and lateral (sideways) erosion has widened the river channel. The river channel has also deepened. A larger river channel means there is less friction, so the water flows faster

the river has a high volume and a large discharge. The river channel is now deep and wide and the landscape around it is flat. However, as a river reaches the end of its journey, energy levels are low and deposition takes place.

Question 3

Compare hydraulic action with abrasion

Answer 3

Abrasion wears away the rock were as hydraulic action forces water and air into gaps and cracks the rock.

Question 4

What is weathering

Answer 4

A way of erosion (for example abrasion and hydraulic action)

Question 5

Levees (embankment)

Answer 5

Like flood walls building levees increases the capacity of the river and are normally built at a distance from the river which increases capacity even more.

Costs: up to 1m per kilometre (expensive)

Question 6

Dredging and flood relief

Answer 6

Dredge the river to increase channel capacity or line it with concrete to speed up river flow

Cost: £50,000 dredging has to be done every year as the channel fills with sediment each time it rains.

Question 7

Flood walls

Answer 7

Build a high wall alongside a river to increase its capacity to prevent flooding.

Costs: depends on type of wall and material
However they dispense water quickly and can increase flood risk downstream.

Question 8

Human factors that can effect flooding

Answer 8

Impermeable rock

Deforestation

Question 9

Two ways climate and geology change river landscapes

Answer 9

Deforestation

Saturated water.