• Coastal Processes

• Management Strategies

• Sustainability Issues

Coastal Study

The North Norfolk Coast

Study Sites

Sheringham

West Runton

Cley-next-the-Sea

OverstrandCromer

Factors Affecting Erosion

•Geology

•Sub-aerial Processes.

•Human Influence

•The Sea

Distance over which waves have to build up

NE 600km Denmark

N 4100km Arctic

Fetch

Cross-section of a typical cliff in North Norfolk

Glacial Till250 - 450 Ka

West Runton Freshwater Peat Bed650 Ka

Chalk60 - 70 Ma

Weybourne Crag1 - 2 Ma

Geology

Sub-aerial Processes Saturation

UndercuttingSlumping

Transportation

S.U.S.T.S.U.S.T.

Erosion Consequences

Loss of 1 metre of cliff annually• Not Uniform

• Coastal Variations

Effects• Destruction of Property

• Loss of Livelihood

• Habitat LossOverstrand Hotel

Coastal Defences

Angled Sea Wall

Groynes

Flat Sea Wall

Rock Armour GroynesRip-Rap

Beach Nourishment

Revetments

Bore Pipes

GabionsShingle Ridge

Coastal Defences

SustainabilityBruntland (1987)“meeting the needs of the present without

compromising the ability of future generations to meet their own needs”

• Example :Groynes are made of wood from rainforests.Therefore we chop down forests to make groynes.Eventually this deforestation leads to global warming and higher sea levels.Consequently there is an increased need for groynes.

Costs and Payments

• Norfolk coastline is 74km long (Hunstanton to Lowestoft)

• 34km of it is being protected by sea defences

• If all defences were taken out and re-built today cost would be £70m

• Annual maintenance budget of £280,000

• Sheringham spent £5.25m on defences between 1995 and 2000

So Who Pays?DEFRA (Department for the Environment,

Food and Rural Affairs)

• Can pay up to 75% of cost for sea defences

• Only contribute 55% in North Norfolk

Local District Councils • Pay the rest, but can get a

‘supplementary credit agreement’ loan

As they pay the majority, DEFRA decide where the defenses will go

DEFRA Criteria For Funding

Urgency

Is the cliff likely to fail again in the next 5 years

Economics

Cost benefit analysis

Priority

Is the area urban or rural in location?

Shoreline Management Plans

“Management of one area of coast may have an adverse

impact on other areas”

• The UK coastline is divided into management cells and sub-cells corresponding to changes in longshore drift

• Norfolk is divided into sub-cells 3a and 3b, with the division roughly at Sheringham

Advance The Line

Managed Retreat Do Nothing

Hold The Line

S.M.Ps. Four Strategies

Tomorrow• Meeting time . . .

• Structure of the day

• Weather

• What you need to bring . . .

1. Weather dependent: waterproofs, warm clothing, extra drink, sun cream

2. Essentials: work stuff, comfortable shoes

• Citizenship –

“take nothing but pictures, leave nothing but footprints”

Cley-next-the-Sea

• Population 600

• Fishing industry

• Freshwater marsh (SSSI), owned by NWT, prone to flooding

• Starting point of shingle spit

Sheringham

• Population: 7,500

• 2nd biggest tourist resort in North Norfolk after Cromer

• Steam railway is a major attraction (125,000 per year)

• Heavy sea defences

West Runton

• Population: 800

• Built up around fishing industry

• Fantastic geology (SSSI)

• Locally important as a Rocky Shore

Cromer

• Population: 8,000

• “Gem of the North Norfolk coast”

• Many sea defences because of weak geology

• Cliff-top settlement

Overstrand

• Population: 1,100

• Highly exclusive tourist resort

• Site of Clifton Way project - experimental sea defences

Flat Sea Wall

• Reinforced concrete

• Maximum life span 100 years

• £3,000 per linear metre

Angled Sea Wall

• Reinforced concrete

• Maximum life span 100 years

• £5,000 per linear metre

• Granite from Norway

• £1-3,000 per boulder (depending on size)

• 100 + years life span

Rip-Rap

• Tropical Greenhart wood

• 30-40yr life span

• £1,000 per linear metre

Groynes

Rock Armour Groynes

• Made from Rip-Rap

• More effective at stopping longshore drift than wooden groynes

• £1,250 per linear metre

• Were made from iron, now flexible plastic

• £ 120 per metre

Bore Pipes

Beach Nourishment

• Movement of beach material from one beach to another

• Longshore Drift transports it along shore

• Replenished each year

• £10 per m3

Shingle Ridge

• Beach material bulldozed into a barrier

• 6 Month lifespan

• £40,000 maintenance each year

• Tropical Greenhart wood

• 30-40yr life span

• £1,500 per linear metre

Revetment

• Cages filled with beach material

• 5-10 year life span

• £50 per cage

Gabions