River Exe Case Study - water

Question 1

How long is the River Exe?

Answer 1

It flows for around 80km from Exmoor to Exmouth.

Question 2

How much precipitation does the River Exe receive a year?

Answer 2

1295mm

Question 3

How much area does the River Exe cover?

Answer 3

around 600km2

Question 4

What is kind of rock is situated in the River Exe?

Answer 4

Devonian sandstone. The riverbed is 80% impermeable.

Question 5

What mitigation has been put in place around the River Exe?

Answer 5

Drainage ditches that drain peatlands and reduce soil water storage.

Question 6

Why is there a long lag time?

Answer 6

The land use is almost 70% grassland, 15% woodland & farmland and 3% peat bogs.

Question 7

Wimbleball Reservoir

Answer 7

• River Haddeo dammed to create WR
• surface area of 150 ha
• supplies water to Exeter and parts of East Devon
• Regulates water flow, flattens river regime, reduces risk of flooding or drought

Question 8

Why was there a need for peatland restoration (Exmoor mires project)?

Answer 8

Drainage ditches had been built to make peat bogs suitable for farming. This increased speed of water flow to the Exe and reduced water quality.

Question 9

Issues before the Exmoor Mires Project

Answer 9

• Peat dried out, causing decomposition and the release of CO2 and Methane
• Peat was dug out as fuel, which therefore caused a fast release of CO2

Question 10

Ways in which the Exmoor Mires Project was successful

Answer 10

• Restored peat bogs by blocking drainage ditches, aiming to cover 2000ha
• More water storage in upper catchments, ensuring steady water supply
• Improved water quality as water was moving slower
• More carbon storage as peat bogs were restored to boggy conditions key for keeping in carbon
• Improved opportunities for education, leisure and recreation
• Improved grazing and water for animals