🏖️Case Study - Slapton Line Management

Question 1

What is the Slapton Line?

Answer 1

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

Question 2

Where is Slapton Sands?

Answer 2

Kingsbridge, South Devon, UK

Question 3

Why is the shingle barrier under threat?

Answer 3

Erosion rates are increasing

Question 4

Where are coastal management strategies installed around the area?

Answer 4

Slapton, Torcross and Beesands

Question 5

How long is the shingle barrier?

Answer 5

7km

Question 6

What defences are in place at Torcross?

Answer 6

A Sea wall

Question 7

When was the sea wall at Torcross built?

Answer 7

1979

Question 8

What happened to the Torcross sea wall in 2001?

Answer 8

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

Question 9

What happened to the sea wall at Torcross in 2014?

Answer 9

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

Question 10

What happened to the Slapton Line after the 2014 storm?

Answer 10

The worst affected section of the road was realigned

Question 11

What length of the road was realigned in 2014?

Answer 11

200m

Question 12

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

Answer 12

12,000 tonnes

Question 13

What was created on the beach at Slapton for protection?

Answer 13

Shingle bastions

Question 14

How effective were the shingle bastions?

Answer 14

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

Question 15

What defences are in place at Beesands?

Answer 15

A sea wall and rock armour

Question 16

When was the rock armour put in place at Beesands?

Answer 16

2016

Question 17

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

Answer 17

2-4 tonnes

Question 18

Why was the rock armour put in place at Beesands?

Answer 18

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

Question 19

What happened to the Torcross sea wall in 2016?

Answer 19

It collapsed

Question 20

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

Answer 20

£250,000

Question 21

How much did repairs to the wall in 2017 cost?

Answer 21

£2.4 million

Question 22

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

Answer 22

710 tonnes of steel and 220m3 of concrete

Question 23

How much shingle was washed away from Torcross in 2015?

Answer 23

27,000 tonnes in one night

Question 24

How much did the shingle at Torcross cost?

Answer 24

£250,000

Question 25

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

Answer 25

5m from a 1000m stretch of beach

Question 26

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

Answer 26

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

Question 27

Why was Hallsands destroyed?

Answer 27

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

Question 28

What are the long term issues with these management strategies?

Answer 28

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

Question 29

How much sediment transport occurs on the beach at Slapton?

Answer 29

Next to none.

Question 30

Processes: Evidence of deposition

Answer 30

Beesands beach

Question 31

Processes: Evidence of transportation

Answer 31

Slapton Sands (barrier beach)

Question 32

Processes: Evidence of erosion

Answer 32

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

Question 33

4 Examples of human interference

Answer 33

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

Question 34

Defences: Length and age of sea wall at Torcross?

Answer 34

319m 1979, modified in 2000 by the Environment Agency

Question 35

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

Answer 35

143m 1917

Question 36

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

Answer 36

795m 1979

Question 37

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

Answer 37

Rock armour

Question 38

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

Answer 38

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

Question 39

Future Defences: Beach Nourishment Key Points

Answer 39

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

Question 40

Future Defences: Shingle Recycling Key Points

Answer 40

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

Question 41

Future Defences: When might shingle recycling be used?

Answer 41

Useful on a small scale as a temporary solution

Question 42

Future Defences: Road Realignment Key Points

Answer 42

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

Question 43

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

Answer 43

Looked at from a social, economic and environmental angle

Question 44

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

Answer 44

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

Question 45

Sustainability: Why was it good that stakeholders were consulted?

Answer 45

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

Question 46

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

Answer 46

Lived experience from Hallsands following the large-scale shingle extraction

Question 47

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

Answer 47

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

Question 48

How many residential properties were at risk of coastal flooding?

Answer 48

48

Question 49

What % of trade is passing?

Answer 49

50%

Question 50

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

Answer 50

£1.78 million

Question 51

What is the main challenge to coastal management?

Answer 51

Climate change

Question 52

Who is the shoreline management organisation at Slapton?

Answer 52

Slapton Line Partnership

Question 53

When was the SLP formed and why

Answer 53

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

Question 54

How much of the beach did the 2001 storm remove?

Answer 54

5m

Question 55

What is the aim of the SLP

Answer 55

To promote a coordinated policy and ensure an appropriate contingency plan

Question 56

What did the SLP decide to do?

Answer 56

Existing defences should be maintained over the next 20 years

Question 57

What was it decided to do with the sea wall?

Answer 57

Maintain and improve it

Question 58

How was the rock revetment repaired?

Answer 58

Through recovery and re profiling of the existing rock armour

Question 59

Cost to repair the rock revetment

Answer 59

£10,000

Question 60

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

Answer 60

Beach recycling

Question 61

How much did it cost to repair the sea wall?

Answer 61

£3 mill

Question 62

How often do groynes need replacing?

Answer 62

Every 20-30 years

Question 63

What is the main road in Slapton called?

Answer 63

A379

Question 64

What is the long term recommendation for Slapton?

Answer 64

Continue a policy of Managed Realignment along the whole coast

Question 65

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

Answer 65

Low

Question 66

Energy at the coastline in Start Bay

Answer 66

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

Question 67

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

Answer 67

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

Question 68

What happened in 2014?

Answer 68

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

Question 69

What happened in 2015

Answer 69

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

Question 70

Why has rip-rap in North Hallsands been ineffective?

Answer 70

Large depletion of the beach as a natural defence