Dawlish Warren field work Flashcards

1
Q

What 6 geographical concepts do you need to think about when answering a question on beach profiles?

A

Wave type
wave frequency
wave direction/ longshore drift
local geology
pebble size
beach management system.

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2
Q

What are the wave types?

A

There are two different types of waves - constructive and destructive .

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3
Q

What are constructive waves

A

Constructive waves have a low wave height, low wave frequency, strong swash, weak backwash and are created by a weak(er) wind over a small(er) fetch.

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4
Q

What are destructive wave?

A

Destructive waves have a high wave height, high wave frequency, strong backwash, weak swash and are created by a strong wind over a large fetch.

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5
Q

What are waves affected by?

A

the fetch - how far the wave has travelled
the strength of the wind
how long the wind has been blowing for

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6
Q

What does a long fetch mean?

A

Fetch length, the size (sea state) of waves produced.

Depends on
wind direction is constant,
greater the wind speed,
more wind energy is transferred to water surface
the larger the resulting sea state will be.

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7
Q

Key terms

What is Primary data

A

data that you collected yourself, first hand.

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8
Q

Key terms

What is secondary data?

A

data you did not collect - it came from another source

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9
Q

Key terms

What is Qualitative data?

A

involves words, images, opinions and is subjective.

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10
Q

Key terms

What is Quantitative data

A

involves numbers and counting, it is objective (fact).

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11
Q

Key Terms
Sampling methods include:
What is Opportunistic sampling?

A

Opportunistic: when samples (e.g. people) are chosen when the opportunity presents itself e.g. whoever walks past.

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12
Q

Key Terms
Sampling methods include:
What is systematic sampling?

A

Systematic: working to a system e.g. picking up a pebble every 10 metres.

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13
Q

Key Terms
Sampling methods include:
What is Stratified sampling?

A

Stratified: collecting a sample made up of different parts e.g. asking people of different age ranges or genders.

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14
Q

How we chose our sites:

Why use a geology map?

A

used the geology map included sites at different rock types - to see how different rock type areas are managed/affected.

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15
Q

How we chose our sites:

Why use an OS map?

A

OS map to include sites with coastal management methods (groynes) – to see how coastal management affects processes.

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15
Q

How we chose our sites:

Why are sites close together?

A

all sites were close enough together that we could collect data from all of them in a day.

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16
Q

How we chose our sites:

Why do sites need to be on the same stretch of coastline?

A

all on the same stretch of coast so affected by the same prevailing winds / waves.

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17
Q

How we chose our sites:

Why is a risk assessment needed?

A

risk assessment to make sure that all sites were accessible and safe to collect data.

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18
Q

Primary data - Groyne

What method can we use?

Why/How

Weakness

Qualitative or Quantitative

A

Method - Groyne drop height survey

Why/ How = ruler measure drop height from the top to the sand on both sides. Expect drop height smaller on west side as sand piles up there.

weakness - Human error - accuracy of measurement.

QUANTATIVE - NUMBERS USED.

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19
Q

Primary data - sediment

What method can we use?

Why/How

Weakness

Qualitative or Quantitative

A

method use? Sediment shape

Why/How - pebble selected either side of groyne - sea edge and back of beach. Shape judges - scale of roundness - have groynes effected longshore drift (LSD)

Weakness - subjective - people judge ‘roundness’ differently will effect LSD

QUANTATIVE - shape judged using sheet.

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20
Q

Primary data - Questionnaire

What method can we use?

Why/How

Weakness

Qualitative or Quantitative

A

method use? Questionnaire

Why/How? Ask people their view of different types of coastal erosion to see how successful the type used is?

Weakness Answers are subjective - limited sample - not totally representative.

QUALITATIVE - subjective

21
Q

Primary data - Interview

What method can we use?

Why/How

Weakness

Qualitative or Quantitative

A

method use? Warden Interview

Why/How? Interview of warden in Dawlish Warren about coastal defences - his opinion?

Weakness Answers are subjective - warden biased toward protecting Dawlish Warren

QUALITATIVE - subjective

22
Q

Secondary data - Geology map

What method can we use?

Why/How

Weakness

A

method use? Geology map

Why/How? Shows rock type - helps with erosion rates - choose sites e.g. hard rock V soft rock
Weakness shows human and physical features at Dawlish Warren - helps choose site some with / without costal defences.

23
Q

Secondary data - OS map

What method can we use?

Why/How

Weakness

A

Method can we use? OS map

Why/How - No human activity seen

Weakness - Might be outdated not show recent changes

24
Q

Secondary data - Environment agency shoreline management plan

What method can we use?

Why/How

Weakness

A

What method can we use? Environment agency shoreline management plan

Why/How - Information various coastal management strategies used and why

Weakness - out of date - published 2017 - biased to positive of coastal management

25
Q

What are soft costal managment systems

A

Soft Engineering – Using nature itself to protect coastline.
Beach nourishment, dune restoration, managed retreat, salt marsh restoration, wetland creation, beach recycling

26
Q

What is beach nourishment?

A

adding sand to restore beach profile - protect against erosion.

27
Q

What is Dune restoration

A

Planting vegetation to reduce erosion, buffer wave action

28
Q

What is managed retreat?

A

coastline to naturally erode, relocating or removing structures at risk

29
Q

What is salt marsh restoration

A

restoring and protecting salt marsh - absorbs wave energy , reduce erosion, habitat for species

30
Q

What is wetland creation

A

construct wetlands - absorbs wave action reduce erosion, valuable habitat wildlife

31
Q

What is beach recycling

A

moving sand from areas of accretion to area of ersion along beach, heloing healthy balanced shoreline.

32
Q

What is hard engineering coastal management systems

A

Building systems to support managment

33
Q

What are sea walls?

A

built parallel to coastline to protect land from wave action.

34
Q

What are Groynes?

A

wooden barriers perpendicular to the coast traps sediment prevents erosion

35
Q

what are revetments?

A

sloping structures that absorb wave energy prevent erosion

36
Q

what are Gabions?

A

wire cages filled with rocks that act as barrier against erosion

37
Q

what is riprap?

A

layer of large stones placed on the beach to protect against erosion

38
Q

Where does the OS map show the groynes are?

A

On the SPIT

39
Q

Why are there groynes on the spit?

A

to protect from erosion

40
Q

How do you gather information about erosion using groynes.

A

Complete a groyne drop height investigation

41
Q

What did the groyne drop height investigation in Dawlish Warren show?

A

There is sand build up on the west side of each groyne and the beach level is lower on each side.

Longshore drift direction is west to east

groynes are preventing the sand from moving along the spit.

42
Q

How doe the sediment size show that the groynes are preventing erosion?

A

The pebble size DOES NOT GET SMALLER from west to east side of the spit.

43
Q

What would it mean if sediment size changed?

A

Smallest sediment would be seen at one end of the beach having been eroded, by attrition, as it is moved by LSD -

THIS IS NOT THE CASE AT DAWLISH WARREN.

44
Q

Are the groynes effective at Dawlish Warren?

A

Yes. They are preventing longshore drift (LSD) which is seen in our groyne drop height survey and the sediment size.

45
Q

How are the communities in Dawlish warren affected positively by coastal management?

A

Questionnaire shows:
80% in favour so they can see the benefit.
Groynes kept the beach making it bigger and attracting tourist
Seawall is bigger and keeps the railway safe
Beach nourishment looks natural.

46
Q

How are the communities in Dawlish warren affected negatively by coastal management?

A

Beach Warden said
Short term work, noise and cost negatively affected people but the long term positives were good - tourism, nice environment , protects Dawlish Warren.

47
Q

What is cost benefit ratio?

A

Is the cost worth the benefits the community gains.

48
Q

Is the cost benefit ration for the costal management system in Dawlish Warren good?

A

The cost benefit ratio means that the coastal defences are currently worth the money - but this may not be the case in the future.

49
Q

Dawlish Warren The accuracy and reliability of the conclusions.

What is the accuracy and reliability of the groyne drop height survey?

A

The results show sediment piling up on the west side of each groyne but there were 4 anomalies that went against the pattern.

Human error can make results less accurate - pushing the ruler into the sand leads to false results.

Results are accurate enough to show groynes stopping LSD.

50
Q

Dawlish Warren The accuracy and reliability of the conclusions.

Are the conclusions reliable?

A

A large range of people were questioned including the Warden (expert)

Problems - not sure if tourists or residents - so not sure if asking the local community.

Warden an expert but could be biased toward success of the coastal management system.

51
Q

Dawlish Warren The accuracy and reliability of the conclusions.

In summary how reliable is the Dawlish Warren field work results?

A

Results are only reliable for Dawlish Warren on THAT DAY

Warden is a reliable expert but we only asked one.

Sample size for questionnaire is small

Groyne drop height survey measure 12/17 groynes on the spit - we could not access those at the end of the spit.

Larger sample needed for sediment size.