Method of Protection How does it work? Advantages Disadvantages Hard Engineering Concrete Wall, curved under the side to deflect the power of the waves. Sea walls reflect rather than absorb wave energy Most effective means of preventing erosion A promenade can be built behind the sea wall for tourists to walk along. More tourists means more money for local people. Most expensive (up to £2.5 million /km) Reflected often scour the base, undermining the wall (may eventually collapse) Large boulders on the beach - lesson the force of the waves by absorbing the wave energy within the gaps between the rocks. Relatively Uses natural materials / rocks Environmentally ugly Can be undermined and removed by due to washing away of sand and shingle beneath. Cages of boulders built into the cliff face - small rocks help to absorb the wave energy. Effective where severe erosion and cheaper than sea walls. Environmentally ugly (usually used in numbers) Cost: approx £350 per metre Wooden structures break the force of the waves and trap beach material behind them. Much cheaper than a sea wall Effective at breaking the force of the waves Less durable than a sea wall – may need replacing quicker. Don't give total protection to base of cliff Environmentally ugly Cost: approx £1,000 per metre
Wooden or in some cases rock fences which reduce longshore drift and make the beach larger which protects the coastline. Reduces longshore drift Encouraging the build-up of the beach and effectively reducing erosion. A larger beach also encourages tourism as more people will come to visit. This will benefit local shops and hotels. This leads to higher employment and businesses will have money to invest in the local area. This is known as the positive multiplier effect. Can increase erosion further down the coast by stopping longshore drift and starving areas further down the coast of sediment. If beaches down the coast become smaller there will be fewer tourists. This leads to higher unemployment and businesses will have less money to invest in the local area. This is known as the negative multiplier effect. Cost: approx each Soft Drains cliffs of water and reduces rotational cliff slumping. Cheap. Is underground so doesn’t spoil aesthetic view. Doesn’t protect the cliff from wave action. Looks ugly when cliff erodes.
Constructive Wave A wave which has a larger swash than backwash Deposition Placing sand and sediment in a certain place by a wave erosion transportation or humans. Destructive Wave A wave which has a larger backwash than swash Discordant Layers of hard and soft rock which run vertically against the coastline forming headlands and bays. Do Nothing An approach that allows natural processes to take their course without any intervention Erosion Breaking down of rock and sediment Fetch The distance a wave travels before hitting the coastline Geological Structure The way in which the rocks are arranged both vertically and horizontally Hard Engineering A heavily managed area of the coastline e.g. sea wall, groyne Hard rock Resistant rock which is harder to erode or weather e.g. granite Headland Outcrop of land at sea made from hard rock Holistic An approach to environmental management that threats the whole area as an interrelated system ICZM (Integrated Coastal Zone Management) A sustainable method of coastal management managing the whole coastal area from the shoreline to several kilometres inland as one area. Longshore Drift The process of sediment moving along the coastline. Mass Movement Rock fall: When fragments or weathered rock fall gravity to the base of the cliff. Slumping: When the bottom of a cliff is eroded by waves it makes the cliff steeper. The cliff often slides downward in a rotational manner, usually triggered by saturation due to rain. Soft rock Coast less resistant rock which is easily eroded or weathered e.g. limestone Spit Sand and sediment which is attached to the coastline but sticks out at sea Stack A detached column of rock located just offshore Strategic Realignment The reorganisation of coastal defences that is often part of managed retreat Stump A stack that has collapsed leaving a small area of rock above sea-level