🏖️Case Study - Slapton Line Management Flashcards

1
Q

What is the Slapton Line?

A

The fragile shingle bar which runs between Slapton Ley and the sea

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2
Q

Where is Slapton Sands?

A

Kingsbridge, South Devon, UK

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3
Q

Why is the shingle barrier under threat?

A

Erosion rates are increasing

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4
Q

Where are coastal management strategies installed around the area?

A

Slapton, Torcross and Beesands

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5
Q

How long is the shingle barrier?

A

7km

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6
Q

What defences are in place at Torcross?

A

A Sea wall

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7
Q

When was the sea wall at Torcross built?

A

1979

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8
Q

What happened to the Torcross sea wall in 2001?

A

It was partially destroyed by a storm and large amounts of sediment were washed away

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9
Q

What happened to the sea wall at Torcross in 2014?

A

The wall collapsed during a storm and the beach was built up again in order to protect it

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10
Q

What happened to the Slapton Line after the 2014 storm?

A

The worst affected section of the road was realigned

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11
Q

What length of the road was realigned in 2014?

A

200m

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12
Q

How much shingle was transported from the Strete Gate area to Slapton?

A

12,000 tonnes

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13
Q

What was created on the beach at Slapton for protection?

A

Shingle bastions

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14
Q

How effective were the shingle bastions?

A

Only for the short term, as up to 45% was washed away in a storm in 2008

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15
Q

What defences are in place at Beesands?

A

A sea wall and rock armour

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16
Q

When was the rock armour put in place at Beesands?

A

2016

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17
Q

How much rock was imported to build the Beesands rock armour?

A

2-4 tonnes

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18
Q

Why was the rock armour put in place at Beesands?

A

To try and stop the wall from being undercut and collapsing again

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19
Q

What happened to the Torcross sea wall in 2016?

A

It collapsed

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20
Q

How much was spent by the South Hams council on emergency flooding funding?

A

£250,000

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21
Q

How much did repairs to the wall in 2017 cost?

A

£2.4 million

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22
Q

How much steel and concrete was used to reinforce the wall?

A

710 tonnes of steel and 220m3 of concrete

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23
Q

How much shingle was washed away from Torcross in 2015?

A

27,000 tonnes in one night

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24
Q

How much did the shingle at Torcross cost?

A

£250,000

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25
Q

How much shingle was lost from the Slapton Line in the storms of 2000/2001?

A

5m from a 1000m stretch of beach

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26
Q

What was initially used to protect the road after the 2000/2001 storm?

A

3000 tonnes of rock armour, later removed due to damage to the SSSI

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27
Q

Why was Hallsands destroyed?

A

Due to dredging of shingle in the early 20th century from the sediment cell, which is virtually closed

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28
Q

What are the long term issues with these management strategies?

A

. May damage to vegetation
. If the barrier was breached, the Slapton Ley lagoon may be destroyed
. Expensive to maintain

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29
Q

How much sediment transport occurs on the beach at Slapton?

A

Next to none.

30
Q

Processes: Evidence of deposition

A

Beesands beach

31
Q

Processes: Evidence of transportation

A

Slapton Sands (barrier beach)

32
Q

Processes: Evidence of erosion

A

Limpet Rocks (wave cut platform)
Dancing Beggars (stacks)

33
Q

4 Examples of human interference

A

A379 (Kingsbridge to Dartmouth)
Car parks along the barrier beach
Start Bay Caravan Club Site
Defences

34
Q

Defences: Length and age of sea wall at Torcross?

A

319m
1979, modified in 2000 by the Environment Agency

35
Q

Defences: Height and age of sheet piling capped with concrete top just north of Torcross?

A

143m
1917

36
Q

Defences: Length and age of Rock Revetment in front of a car park, north of Torcross?

A

795m
1979

37
Q

Defences: What protects the more vulnerable parts of the A379?

A

Rock armour

38
Q

Why was a report by Scott Wilson and the University of Plymouth commissioned in 2003?

A

Determine appropriate future shoreline management response
Look at impact of existing sea defences

39
Q

Future Defences: Beach Nourishment Key Points

A

Import shingle- raise + widen beach, additional protection for road
£1.14 million every 10 years to maintain
Material from Isle of Wight, matches existing
RULED OUT

40
Q

Future Defences: Shingle Recycling Key Points

A

Excavation of material from Strete Gate beach
Place on beach at Slapton
Raise + widen beach + protect road
Large environmental impact- disrupts geomorphology
£60,000, not guaranteed to work
RULED OUT

41
Q

Future Defences: When might shingle recycling be used?

A

Useful on a small scale as a temporary solution

42
Q

Future Defences: Road Realignment Key Points

A

Move A379 landwards
Proactive- before damage
Reactive- after storm
CHOSEN
Scored highest on tables

43
Q

Sustainability: Why are the future defences considered to be sustainable?

A

Looked at from a social, economic and environmental angle

44
Q

Sustainability: Why is it good that all strategies have been put on an open spreadsheet?

A

Constantly reviewed
Changed if any unexpected events
The sheet looks up to 2105, so is long term

45
Q

Sustainability: Why was it good that stakeholders were consulted?

A

Experts, authorities and local people could talk, share lived experience and discuss their worries with the strategies

46
Q

Sustainability: Why was the owner of Streete Gate beach useful in the discussion?

A

Lived experience from Hallsands following the large-scale shingle extraction

47
Q

Why could it be argued the strategies aren’t sustainable?

A

Existing strategies aren’t being removed
January 2018, road destroyed, still not fixed

48
Q

How many residential properties were at risk of coastal flooding?

A

48

49
Q

What % of trade is passing?

A

50%

50
Q

How much funding could be requested from the Environment Agency to coastal risk management activities over the next 20 years?

A

£1.78 million

51
Q

What is the main challenge to coastal management?

A

Climate change

52
Q

Who is the shoreline management organisation at Slapton?

A

Slapton Line Partnership

53
Q

When was the SLP formed and why

A

. 2001
. After a storm damage a key road between Slapton and Street Gate

54
Q

How much of the beach did the 2001 storm remove?

A

5m

55
Q

What is the aim of the SLP

A

To promote a coordinated policy and ensure an appropriate contingency plan

56
Q

What did the SLP decide to do?

A

Existing defences should be maintained over the next 20 years

57
Q

What was it decided to do with the sea wall?

A

Maintain and improve it

58
Q

How was the rock revetment repaired?

A

Through recovery and re profiling of the existing rock armour

59
Q

Cost to repair the rock revetment

A

£10,000

60
Q

What management was done to work with the natural process to increase beach size?

A

Beach recycling

61
Q

How much did it cost to repair the sea wall?

A

£3 mill

62
Q

How often do groynes need replacing?

A

Every 20-30 years

63
Q

What is the main road in Slapton called?

A

A379

64
Q

What is the long term recommendation for Slapton?

A

Continue a policy of Managed Realignment along the whole coast

65
Q

How high is the risk to the shingle bank for the next 30-50 years?

A

Low

66
Q

Energy at the coastline in Start Bay

A

Coastline has areas of both high and low energy with both erosion and depositional landforms

67
Q

Where is the most heavenly managed areas and what do they have?

A

Torcross and Beesands which both have sea walls protected by rock armour

68
Q

What happened in 2014?

A

Shingle bastions were built to try and reduce LSD and erosion but they were soon eroded

69
Q

What happened in 2015

A

250,000 tonnes of shingle was moved from Street to Torcoss only to be washed away overnight in one winter storm

70
Q

Why has rip-rap in North Hallsands been ineffective?

A

Large depletion of the beach as a natural defence