EASTBOURNE BEACH MANAGEMENT WORKS Introduction

The beach frontage that is managed by Eastbourne Borough Council is 5.8km in length and

extends from Holywell to Langney Point. The maintenance of the beaches in front of

Sovereign Harbour is the responsibility of the Environment Agency.

Timber groynes retain a wide shingle beach which is backed by a seawall between Holywell

cliffs and the Fishing Station. To the north of the Fishing Station there is no seawall present.

Towards Langney Point a number of rock structures reinforce the defences.

The frontage as a whole is subject to erosion, with the low lying land to the east of the Pier

also being at risk of flooding from the sea.

Background

Eastbourne is no different to the rest of the English Channel coast in having to deal with rising

sea levels, increased storminess and naturally eroding beaches. Shingle is no longer being

brought ashore by the sea in sufficient quantity to naturally sustain the beach, and flint

released from eroding chalk cliffs to the west is equally inadequate. In common with many

other parts of the country, the level of protection afforded to Eastbourne is only maintained

by directly adding shingle to the beach to replace material that is lost as it drifts eastward

along the coast.

A series of storm events in the late 1980's resulted in a significant reduction in beach levels,

wave and shingle overtopping of the defences and flooding and damage to seafront

properties. The reduced beach resulted in increased loading upon the old timber groynes,

resulting in failure which exacerbated the beach losses and overtopping. The frequency of

repair increased to a level where the need for a capital works scheme was clear.

This led to the re-construction of all the groynes along the whole frontage and the

renourishment of the beach with around 1 million tonnes of shingle. The scheme was

completed in 1999.

Whilst the timber groynes significantly reduce the rate of longshore sediment transport, they

do not prevent the movement of the beach completely. At the time of construction, it was

recognised that beach management activities would be necessary in order to maintain the

standard of protection afforded by the scheme.

Recent works

2008-2009

Aside from monitoring, Eastbourne Borough Council has been unable to undertake beach

management activities between 2004 and 2008 due to uncertainty surrounding the national

flood and coastal defence budget. By 2008, a number of groyne bays had become particularly

vulnerable. Beach levels were approaching the failure level defined by the Beach

Management Plan and the risk of undermining of the sea wall had increased to an

unacceptable level. This led the Council to undertake re-cycling and renourishment work in

winter 2008-09 to increase the beach volumes in the Pier area. These works was approved

and grant aid funded by the Environment Agency.

Recycling involves re-using shingle

already on the beach. Material from groyne bays in surfeit is moved to others where there is a deficiency. Excavators load surplus beach into dump trucks, which then travel along the beach and tip the shingle where it is needed. Bulldozers then push the

beach into its required position.

2010-2011

Whilst the work carried out in 2008-09 reduced the risk in the vicinity of the Pier, it was

recognised that the ongoing losses since the beach management operations stopped in 2004

have led to an overall reduction in the standard of protection for the frontage. A scheme

designed to return the beaches to a satisfactory condition was submitted to the Environment

Agency and received approval in December 2011.

The works; carried out between January and March 2011, involved depositing around 200,000

cubic metres of shingle onto the beaches between Langney Point and the Wish Tower. The

material was dredged from a licensed extraction site in the English Channel off the Isle of

Wight and pumped ashore from the dredger via a sunken pipeline.

The floating pipeline is delivered to the beach.

The temporary pipeline first came ashore in the area of groyne 76, opposite Princes Park at the eastern end of Royal Parade. It was

subsequently moved to near groyne 28 at the Wish Tower.

Dredging was undertaken at low water

so that the vessel could time her arrival at Eastbourne to coincide with

high water. About 1km offshore she connected to the floating end of a temporary pipeline that was laid on the seabed. Her cargo was mixed with sea water and then pumped ashore. Deliveries were made every high tide, seven days a week, until the necessary

quantity had been delivered.

The dredger connecting to the pipeline.

Aerial view of the work being carried out near the Wish Tower.

Shingle is pumped ashore at the Wish Tower

Excavators load much of the delivered shingle into dump trucks so it can be moved to the precise groyne bays where it is needed

In addition some 40,000 cubic metres of shingle was recycled from beaches that were overfull

and placed on the beaches at the Holywell end of the frontage. The reason we have to do this

is because of the environmentally sensitive nature of this frontage which is designated as a

Site of Special Scientific Interest (SSSI). Natural England have stipulated that only recycled

material will be used at the western end of the frontage adjacent to Holywell Reef, to avoid

possible sediment impact on the Reef.

Environmental restrictions meant that in order to avoid possible damage to Holywell Reef only recycled shingle was used at the western end of the frontage. This meant that shingle was dug from existing beaches near the Wish Tower and delivered by dump trucks to the groyne bays between the Wish Tower and Holywell.

2011-2012

The strong winds on the 12th December 2011 put the coastal defences under a severe test but

what the event demonstrated was that the beaches are performing well and preventing low

lying parts of the town from flooding from the sea.

However, it was evident that the profile of the beaches had changed following the storm and a

post storm survey confirmed there had been a significant draw down of shingle.

As part of the approved 5 Year Beach Management Strategy, plans were already in place to

carry out an annual beach replenishment operation. The Environment Agency had previously

sanctioned a grant of 160K to pay for these works that are part of the ongoing programme

of works, designed to ensure the integrity of Eastbournes coastal defences. We were

subsequently successful in achieving agreement to increase this funding to 200k to pay for

additional shingle to replace losses caused by the storm.

The works operation will be carried out in March 2012 by Pevensey Coastal Defence Ltd.

(PCDL) as part of the Coast Protection Maintenance Contract. The total estimated

replenishment volume required is 9,750 cubic metres. Normally importing this amount of

shingle would be by road because it would not be cost effective to mobilise the dredging

operation that was used for the 2010-2011 works. However, the delivery by road option

would involve around 700 lorry movements and take several weeks to complete.

In order to try to reduce this impact it was decided that an operation whereby beaches are re-

nourished using an offshore vessel which pumps shingle directly onto beaches would be

utilised.

Shingle will sucked from the sea bed of a licensed area of the Owers Bank near the Isle of

Wight by the dredger Sospan Dau, taken back to Eastbourne and delivered to the beach

over high tide. The dredger will come very close to the beach and discharge a mixture of

sediment and water using a technique known as 'rainbowing' that creates a mound of material

high on the foreshore. Discharge will take about one hour and the vessel will return to the

dredge area for the next load with the intention of being back on the beach for the next high

tide. Once replenishment has started, the operation is continuous until the required volumes

have been delivered. Only adverse weather conditions in either discharge or dredging areas

will temporarily delay the operation.

The dredger Sospan Dau

The beaches that are due to be recharged are in front on the Wish Tower, at the Bandstand

and either side of the Pier.