River Exe

Question 1

How long is the river Exe?

Answer 1

82.7km

Question 2

What is the source of the river Exe?

Answer 2

Exe head in highland area of Exmoor.

Question 3

How much of the drainage basin is impermeable?
What is the main impermeable rock?

Answer 3

84.4%, (underlain by impermeable rock - Devonian sandstone)

Question 4

Outline the process of flooding stemming from impermeability

Answer 4

84.4% impermeable
—> surface runoff is higher —> soil moisture cannot percolate, so soil becomes easily saturated —> flooding

It additionally leads high drainage density, creating tributaries.

Question 5

Outline the land use of the river Exe drainage basin?

Answer 5

67% used for agriculture

Question 6

67% of the drainage basin is used for agriculture, go into detail as to what effect this has:

Answer 6

-Deforestation has occurred
–>
-Less transpiration + Poorer soil quality
–>
-Therefore there is a need for irrigation
–>
-Drainage ditches have been dug
–>
increased velocity of water + increased transport of silt
–>
-Decreases water quality + increases sedimentation downstream

Question 7

Describe the water balance of the Exe river drainage basin:

Answer 7

Precipitation = Discharge/Runoff + Evapotranspiration
1295mm = 844mm + 451mm

Question 8

What percentage of precipitation is found as runoff?

Answer 8

65%

Question 9

What is the reservoir constructed along river Exe?

Answer 9

Wimbleball reservoir

Question 10

How much water is in Wimbleball reservoir?

Answer 10

150 hectares

Question 11

What are the effects of Wimbleball reservoir?

Answer 11

-Surface storage increase
–>
-Discharge controlled
–>
-Prevent flooding and establish water transfer

Question 12

In the Exmoor mires project, what was being restored, and how large was it?

Answer 12

Peat bog
2000 Ha