What determines whether a particular stretch of coastline is protected or not? Whether land is protected or not comes down to the economic value of the land Protected Unprotected Land of economic value is protected Robin Hood’s Bay 1770-1994, 200 houses went over the cliffs Caravans/cheap housing that is sparsely distributed

A) Hard engineering

1) Groynes

A) Hard engineering 1) Groynes Mappleton, Yorks. coast £10,000 each (wooden groynes) £1.5m each (rock groynes) What are they designed to do? Stop longshore drift Further down the coast this may mean that beaches are starved of sand and shingle

2) Sea Walls

This is reduced by absorbing the energy and angling the wall 2) Sea Walls Expensive at £5,000/m Designed to stop erosion, but what landforms would that prevent being created? Would you rather go on holiday and see Old Harry or a sea wall? This is reduced by absorbing the energy and angling the wall Energy is reflected (not absorbed). Over time the energy scours the base of the sea wall undermining it, causing it to collapse

3) Gabions

3) Gabions Small rocks, bound in place by cages absorb the wave energy and reduce erosion Much cheaper than sea walls £1000/m, but do you think they are attractive?

4) Revetments

4) Revetments £1,000/m Open structure of planks absorb wave energy, but allow sand and shingle to build up beyond Are these attractive?

5) Rock Armour and Rip Rap

5) Rock armour or Rip Rap Relatively cheap £1,000/m, but considered environmentally ugly When resting on sand and shingle they may be moved out of position by waves

Gabions and Groynes

6) Gabions and groynes together Why might you choose to implement more than one coastal management strategy at a time? To protect against erosion and longshore drift

How attractive do you consider these to be? B) “Soft” Engineering Less expensive than hard strategies Overall soft engineering is less expensive, longer term, attractive and sustainable as they work with natural processes, causing less damage. Longer term, more attractive and sustainable as they work with natural processes

1) Beach Nourishment Sand and/or pebbles are brought in to replace material that has eroded away. Where do you think this replacement material has come from? It has been dredged from the sea bed. In some cases it is pumped onto the shore. The beach is widened; how will this affect the energy of the waves? Advantages: Helps protect against direct wave attack and longshore drift. Disadvantages: Alters natural ecosystem and may cause damage to marine life. Must be repeated relatively frequently, thus costly over time. It will reduce the energy that the wave has meaning less erosion. Cost: £100/m/yr

2) Stabilising Sand Dunes Grasses are planted in the sand dunes to bind them together, holding them in place. Adv: Works in harmony with natural ecosystem; sustainable Disadv: can only be used where dunes already exist. Artificial dunes can be created, but these are not replenished and so do not last long. Footpaths may be designated. Why might this be? To reduce trampling of the dunes by people, which erodes them

3) Managed Retreat When the land by the sea is of low economic value it may be allowed to erode. In some cases this eroded material forms beaches which naturally protect the coast. Adv: Cheap and sustainable! Disadv: People lose homes, land and livelihoods

Holderness case study (landform case study)

Why protect/manage the coast?: Case Study Holderness Coast Locally, rates of erosion have been up to 10-20m with waves biting coast away Over 30 villages have been lost since Roman times, erosion has been taking place for last 6000 yrs Holderness Coast is fastest eroding stretch of coastline in Europe – an average of 2 metres fall into the North Sea each year

Holderness Coastline Video - Answers Chalk deposits Wave cut notch erosion Boulder clay- left by the ice sheet The boulder clay is easily eroded as it is a soft rock Longshore drift Groynes RipRap, they stop the waves eroding the coastline by allowing the wave to break on them and spread out the energy

Holderness Coastline Video cont’d As there is no erosion, down the coastline there will be no deposits and so more erosion occurs 16m has eroded in 35 years Sea wall and rip rap. Sue Earl does not live in a settlement, her farm was deemed as not worth protecting. Spit- longshore drift deposition formed it. Groynes were built to maintain it. Shifting mudbanks Too expensive, and there are no important settlements.

High energy waves because of long fetch Chunks of coast slump down the cliff Soft boulder clay Thin, narrow beaches do little to absorb wave energy Holbeck Hall, Scarborough Why are the beaches thin and narrow? The beaches are thin because the material is carried away by longshore drift

Holderness Coast – Cliff Processes Rain water enters cracks Cracks formed by wetting and drying Boulder Clay Cliff Material slumps down the cliff Removal of slumped material by sea Click once to start animation. Slip plane developing Sea Beach

Mappleton and Holderness Coast