River Exe Case Study

Question 1

Describe the impacts humans have had on the river exe

Answer 1

Wimble ball reservoir built - 150 hectares
Regulates the river regime, by preventing run off variation

Peatland destruction
Drainage ditches dug for farming
Leads to More silt being carried downstream
Dried peat surface causes decomposition therefore methane release also oxidation occurs so CO2 lost
The ditches cause unfavourable conditions for further plant growth

Question 2

How long is the river exe? Where does it run from and to?

Answer 2

82.7 Km from tiverton to exmouth

Question 3

What is the major rock type along the river exe?

Answer 3

Devonian sand stone

Question 4

Describe the run off variation along the river exe.

Answer 4

Very high precipitation over exmoor
Peaty land is very good at absorbing the water
Rapid run off occurs where drainage ditches have been dug
Impermeable Devonian sand stone reduces percolation
Despite this lots of wood land so isnt as flashy as would be expected

Question 5

Describe the exmoor mires project

Answer 5

Project to restore the peat bogs
Blocking drainage ditches with peat and moorland bails
Aims to restore 2000 hectares of land

Question 6

Describe the impacts the exmoor mires project has had

Answer 6

Slowed water transfer
Improved water quality = cheaper to clean as well as a better habitat therefore increased biodiversity
Re wetting peat bogs prevents the oxidation so reduces the volume of CO2 lost
Greater biodiversity

Question 7

Give facts on the success of the exmoor mires project

Answer 7

1000 hectares restored so far
100Km drainage ditches blocked
Water table risen by 2.65 cm
Reduced run off by 2/3

Question 8

Describe how data has been collected along the river exe

Answer 8

3 data collection sites built
Electric contact dip that measures the depth
Many small bits of equipment within the old drainage ditches to see the effects here