Monday 16 November 2015
On Tuesday 10th November the Guernsey Press printed an article on the future of the WWII anti-tank wall at L'Ancresse Bay.
The report contained various misunderstandings of the situation at L'Ancresse. The Environment Department would like to take the opportunity to let islanders know about the proposals for East L'Ancresse where the wall is deteriorating.
For more information please contact the Department via email: env@gov.gg, or call the Environmental Services Unit on 717200.
1. At East L'Ancresse 200m of the anti-tank wall from the eastern slipway is badly damaged (aerial view attached). This is the only
section of the 925m long WWII wall under consideration by the Environment Department.
2. There is currently no need or intention to consider removing any other section of the anti-tank wall at Pembroke/L'Ancresse. Over 700m
of the WWII wall and its heritage as a military defence would remain.
3. There is risk of loss of the small kiosk at the eastern slipway as stated by the Guernsey Press. The current kiosk is in a vulnerable
location.
4. There are currently no plans to remove the eastern slipway.
5. There is no risk of loss of the Beach House Café or any of the car park areas.
6. The damaged anti-tank wall at the eastern end of the bay has no foundation and the sections are 'sitting' on the sand beneath it. The
wall has been gradually rotating on its base for decades.
7. The 200m of anti-tank wall at East L'Ancresse is now considered beyond economic repair. A series of concrete aprons have been
constructed between the 1960s and 1990s. Repeated and extensive repairs have been undertaken over the years but these have
not been successful at the eastern end due to the continual rotation of the wall which is pushing the apron sections away from the
base.
8. The Department recognises the safety concerns that result from the condition of the damaged sections of concrete apron. The
Department will investigate options during winter 2015 in respect of addressing those safety concerns with the intention, subject to
the outcome of those investigations, of carrying out works in early spring.
9. The vertical wall was cast in sections and at East L'Ancresse there is notable deterioration with significant horizontal cracks established
in some sections.
10. The high vertical wall is built in front of the natural beach head at the eastern end. Its position causes considerable overtopping of wind
driven water at high tides and also movement of beach sand away from the base of the wall, particularly in storm conditions.
11. The cost of removing the 200m eastern section of damaged wall and creating a managed realignment of the natural beach head in this
area is estimated at £750,000-£800,000. The estimated £2,750,000 quoted by the Guernsey Press refers to the cost of removing the
entire 925m of the anti-tank wall which is NOT under consideration.
12. A managed realignment of the beach with a protective boundary of sand dunes or shingle with protective gabions, rock armour or
landscaping to protect L'Ancresse Common would allow the sea to run out to its full extent on each tide. This is currently what happens
at L'Ancresse to the east of the slipway where there is shingle and a low rock armour bank to the edge of the grassland. The Common
here does not flood at high tide and there is no dramatic erosion in the absence of a concrete wall.
13. A managed realignment at East L'Ancresse should allow a sandy beach area to develop for visitors and offer a larger area of dry sand
between tides.
14. Grandes Rocques and Port Soif are both backed by managed dunes with some rock armour. The cost of managing these natural
defences year round is minimal compared with a concrete or masonry wall. At Grandes Rocques and Port Soif there is minimal risk of
coastal flooding to the roads, utility services and the properties adjacent. Both beaches are very popular with families
15. Rebuilding a replacement vertical wall in the same position at East L'Ancresse would not prevent the existing problem of overtopping
here which can only get worse as sea levels continue to rise. Rock armour in front of the wall would be needed to reduce the power
of the sea and would, in time, greatly reduce the area available for recreation.
16. Managing a re-aligned beach head at East L'Ancresse as sea levels continue to rise would be a gradual process through landscaping
behind it. The level of beach amenity for visitors should be unchanged.
17. Royal Haskoning's report on Pembroke/L'Ancresse of 2012 concludes that 'The land behind the bay is at such a level that it is only into
the third epoch (50 to 100 years in the future) that there is likely to be any substantial risk affecting the land to the south of L'Ancresse
Common. In addressing this in the future, it is seen as more sustainable to landscape the narrow valleys in such a manner as to achieve
a retired level of protection that will not impact on and force the need for works at the sea front.'
18. The Duke of Richmond map of 1787 indicates military defences which were possibly small forts along the edge of the bay. These were
interspersed by structures which could have been earth banks or walls set further back from the forts. In either case the structures were
almost certainly for military defence and not coastal defence.
19. Should a decision in the future be made to manage such sea level rise by hard defences, the current wall at L'Ancresse East could play
no part in such a construction as it does not have the structural integrity to be built on. In other words it would need to be removed to
allow a new structure to be developed.
Note: Pembroke/L'Ancresse bay is approximately 1,400m along the coastal edge between the rock outcrop at the western end and the rock outcrop at eastern end.
Contact Information:
Environmental Services Unit
Environment Department
Tel: 01481 717200
