river exe Flashcards

1
Q

the river exe introduction

A

River Exe, river in southwest England, originates from its source on Exmoor in Somerset, flows southward 60 mi across Devon to its estuary beginning at Exeter and into the English Channel at Exmouth.

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2
Q

why is the river exe important

A

important river for fishing salmon and trout

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3
Q

physical reasons for why the river exe has a short lag time

4 reasons

A
  1. very steep slopes (170m median altitude)
  2. only 13% of the drainage basin is woodland (little interception)
  3. only 2.5% of all bed rock has high permeability (less percolation)
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4
Q

how many properties are at risk from a river exe flood

A

11,000 properties

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5
Q

how many properties are at risk from a river exe flood

A

11,000 properties

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6
Q

human reasons which increases likelihood of flooding

A
  1. 80% of the drainage basin is farmland. Soil in these areas are compact as they are walked on. this decreases soil capacity. (less infiltration)
  2. in the 1900s farmers were encouraged to cut ditches in the moorland meaning the water wasn’t intercepted by the peatland
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7
Q

peatland restoration negatives

exmoor mires project

A
  1. costs £2 million
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8
Q

peatland restoration positives

exmoor mires project

A
  1. as the peatland stays wet it doesn’t oxidise and therefore reduce the amount of carbon released into the atmosphere
  2. encourages the growth of sphagnum moss which can hold 20 times its weight in water
  3. 6000 olympic sized swimming pools are stores in this moss land
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