Coastal erosion and management on the north Norfolk coastline

A2 coursework

Cley next the sea

• Managed to prevent coastal flooding and protect the wetland habitat.

• Salthouse village is protected only as a consequence of the wetland habitat being there.

• Salthouse flooded in 1953 – 1 death• Flooded in 1993 and 1996 when A149 was

cut off for 6 weeks

Landuse behind Cley

Looking east from Cley

Shingle ridge is bulldozed to maintain the barrier to protect Salthouse village

Looking west from Cley towards Blakney Point (coastal spit)

Westerly movement of material by LSD

Management conflict-managed retreat V secondary buffer ridge??

Looking up the beach from the shoreline

Shingle ridges/berms

Top of beach

Landuse behind Cley

Managed shingle ridge Flat saltmarsh land

Salthouse village

Weybourne

• Do Nothing approach.

• Rapid retreat as no management plan.

• Agriculture is main landuse

Looking west towards Cley

Unmanaged shingle ridge

Looking east towards Sheringham

Chalk/unconsolidated sand and glacial till cliffs

Revetments had previously been laidAlong the cliff but post 1998 these were removed following a storm breach and has now been left unmanaged

Cliff face showing evidence of slumping

Under the shingle beach there is a chalk WCPEvident during storm periods

Slumping

Sub-aerial weathering

Conglomerates

Unconsolidated sand

Chalk with flint nodules

Chalk-evidence of bedding planes

Wave cut notch by corrasionCave

Weybourne crag

Evidence of coastal management

Cley next the SeaFlat saltmarsh

Gently dipping slopes away from the sea

Sub-aerial weathering

Evidence of gulleying due to sub-aerial weathering through theUnconsolidated glacial till and sand deposits

5 coastguard cottages approximately 10m from cliff (potential interview)

Sheringham

• Hold the existing line approach.

• Multiple defences used

• Victorians built first sea wall

• Major tourist town – high value landuse

• Great ice cream and fish and chips!

Undefended Sheringham-looking west towards Weybourne

Sheringham golf course

Chalk dipping beneath sealevel Leaving glacial deposits exposed

Evidence of slumping

LSD now eastwards

Start of defences (west of Sheringham centre)-Groynes

Hinged doors allow shingle movement from west to eastWEST

EAST

Sheringham West Beach

Original Sea Wall not included in sea wall replacement scheme – the wider beach offered greater protection

Rock Armour buried by shingle helps to prevent scouring of sea wall

Sheringham town centre

Fishermen’s Slope – in 1986 beach level fell by 2.5 m due to scouring

Sea wall from 1900 resurfaced with concrete in 1988 and entirely replaced in 1993 -4

Rock Armour and Rock groynes

Narrow beach here = more erosion

Sheringham East

Drainage pipe in cliff to Help prevent saturation of soil

Drainage hole allows water to Flow onto promenade

Sheringham East – the end of the sea defences

Cliff slumping along undefended stretch

1988 – Beach nourishment used12000 tonnes of flints were deposited into The bays East of the ‘tank’

Sheringham town centre

Tourist facilities

High value landuse in Sheringham town centre – Sea Defences hold the existing line

£1.5 million spent in 1998 on replacing and repairing wooden groynes And installing rock groynes

West Runton

• Managed Retreat.

• Agricultural landuse

• Fossil evidence from Tropical climatic period

West Runton has few tourist amenities; Low value; Managed retreat

Short sea wall protects café and toilet block

Dark band at base of cliff marks line of a tropical river which meandered East to West 600 000 yrs bp – Known as Cromer Forest Bed

Many fossil remains found including the West Runton Elephant

Cliffs are glacial till and prone to Slumping – results in a gentle profile

WCP forms rocky outcrop

Erratics from Northumberland (Dolerite) and Norway (Rhomb Pomphry) found here

Low value landuse – agriculture and caravan park

Weight of farm machinery has encouraged cliff collapse along the coast

Overstrand

• Hold the existing line

• Multiple hard engineering strategies

• Main issue is slumping of boulder clay cliffs

• Red lining – no new development allowed between a designated line and the cliff. Redefined every 5 years.

Overstrand uses multiple sea defences – groynes and sea wall

Gabions allow water to pass through and hold back slumped material

Sea Wall also provides a promenade (tourist amenity)

Wooden Groynes prevent LSD

Sand beach means a gentle profile

Boulder Clay cliffs are prone to slumping

Gabions hold back slumped material - A successful measure

Drainage holes are found in concrete wall

Bore holes sunk into ground in high risk areas to remove water

The old coastal path was closed off and the road diverted.

Wooden Revetments

Flint nodules caught in gaps – reduce effectiveness of the sea defence

HDE and a Revetment

5ft 5 ¾

My bag!

Steel girders – foundations for defence?

Re-curved sea wall with drainage holes

Coastal path – severed in 2002 due to slumping

Foundations of Overstrand hotel

Vegetated area suggests no recent slumping

Former cliff line

Foundations

Clifton Way

• 1990 – 45m cliff recession

• Nov 1992- 15/20m recession

• Jan 1994 – 20 /25m in just over 2 weeks.

• 30 year old Bungalows deemed worthy of protection.

• £1.4 million spent on regrading scheme and putting in defences

Slope was regraded after a loss of 100,000 tonnes of material in 1994

Lack of vegetation

Drainage channels

Rock armour at base to prevent further slumping and undercutting

1995 – area excavated and layers of sand and synthetic matting, Chalk and boulder clay were used to rebuild the slope.

Drainage channels, bore holes and inspection holes were installed

Council access road had been re - routed twice before 1994

New access road to beach for maintenance

View from beach up Clifton Way

Revetments placed infront of rock armour

Access roadBungalows are here!

Managing the coast

• Shoreline management plan – based on sediment cells

• Reviewed every 5 years

• ‘…it is a live working document and must be capable of change’

Four options

• Do Nothing – no defences except for safety measures

• Hold the exisiting line – intervene to hold the existing defence where it is.

• Advance the existing line – move existing sea defence forwards

• Managed retreat – allow nature to take its course and intervene where necessary

Possible project titles• How effective are the coastal management strategies at X?• A comparison of beach and cliff profiles at X and Y?• A comparison of coastal protection strategies at X and Y?• What factors influence the beach and cliff profiles at X?• How do the beach and cliff characteristics of defended and undefended Sheringham

differ?• How are the coastal defences at X perceived?• Do residents and tourists perceive coastal management strategies differently? A case

study of Sheringham.• What physical and human processes influence the coastline at X?• Is there any evidence of longshore drift on Sheringham beach?• Which has the most effective coastal management strategy – Sheringham or Overstand?• Protecting coastlines against erosion is more important than protecting them from coastal

flooding? A study of Cley –next- sea and Sheringham.• To what extent do physical processes affect the type of coastal management strategy

chosen? A comparison of Sheringham and Weybourne• An evaluation of human influence on beach and cliff profiles at Sheringham, Weybourne

and Overstrand

What now????Thursday• 1 day group fieldwork – visit and collect data at each

site (5 in total)• Thursday eve- Collate data. Decide on title and

devise any further data collection techniques (EIA, CBA etc)

Friday• Individual data collection • Friday eve – write up methodology and process data• Saturday – extra data collection / photos etc