Please enable JavaScript.

Coggle requires JavaScript to display documents.

Coasts: EQ4 - Coggle Diagram

- - - - Beach Nourishment/Replenishment replaces lost sediment to enlarge the beach, so that wave energy is dissipated, thus erosion rates are reduced. This is a relatively cheap strategy, and can have other benefits such as increased tourism. This can be seen in Lyme Regis, where annual beach replenishment occurs by dredging sand from the harbour, and also occurs in Sitges. Limitations include the need to repeat the process, often annually. It also upsets the equilibrium of the sediment cell, and dredging to source the sediment further disrupts the sediment cell.
      - Cliff Regrading + Drainage - cliff slope angles are reduced to increase stability , and re-vegetated to reduce surface erosion. Adding drainage into the cliff reduces over-saturation and mass movement risks. This has been used along the Bournemouth, Christchurch and Poole coastline, where cliff angles have been reduced to a minimum of 35 degrees.
      - Dune Stabilisation - Dunes already act as a natural defence, but are vulnerable to damage from natural and human factors (footpath erosion, storm events). Dune stabilisation includes the use of fences to reduce wind speeds across the dunes, and marram/lyme grass replanted to further stabilise the dunes. Establishing wooden paths over the dunes can help reduce footpath erosion. Recycled Christmas trees can even be used to act as a biodegradable storm breake.
- - - - 3 key focus areas of ICZM policy:
        
        Coasts are to be managed by sediment cell, as opposed to political boundary.
        
        Recognises the importance of coastal zones for people's livelihoods, but also the impact of human activities on natural coastal features
        
        Recognises the need for sustainable management to balance economic development and environmental sustainability.
    - - The entire England + Wales Coastline has been divided into sections based on sediment cell, with each zone of coast given a Shoreline Management Plan.
        
        Within each Shoreline Management Plan, research is carried out and data collected (physical and socio-economic) before decisions are made on which of the 4 approaches should be taken.
        
        Case Study: Lyme Regis, Dorset
        
        Facing high rates of erosion and a town constructed on unstable clay cliffs, Lyme Regis also needed ICZM for a sustainably future.
        
        After consulting various interest groups and cost-benefit analysis, a variety of strategies were implemented on different sections of the coastline. A sea wall was built with rock armor to protect the harbour and fishing fleet. The harbour is dredged annually for beach replenishment, which attracts tourism. A 390m sea-wall was also built in the east of Lyme Regis, to stabilise slopes at Church and East cliff.
        
        The whole integrated scheme was delivered over many years, and deemed one of the largest and most complex protection schemes in England in years.
      - 1. Advance the Line 2. Hold the Line 3. Managed Retreat 4. No Active Intervention
        
        To choose the correct option for an area, the government takes into account a range of data.
        
        Technical Feasibility test - if there is a threat, what defence strategies would work effectively?
        
        Cost benefit analysis are the feasible defence options value for money. This is calculated using the economic land value.
        
        Environmental Impact Assessment investigates sustainability - considering knock-on effects down the coast and the environmental value of land changed by management strategies.
        
        Social + Political considerations are then taken into account if the decision is close. If campaigns have been run by groups to change government decision, this can sometimes work in close calls.
        
        Physical data - historical maps and future predictions, to see if the area needs any coastal protection, and if so to what extent.
        
        Conflict can emerge as a result of policy decisions, or "winners" and "losers". "Winners" often consist of residents of larger towns or where industry is located. "Losers" often live in small isolated settlements or medium sized villages that don't quite pass cost benefit analysis.
    - - One section of the coastline held British Gas Terminals, responsible for 1/4 of the gas from the North Sea taken into England ( a national asset). This section of coast easily passed cost-benefit analysis, and thus a 1km revetment was built at the base of the cliff by the terminal site, at a cost of £6.6 million.
      - Further along, the village with a population of 95,000 at the time wanted defences to be extended to protect their homes from the rapid rates of erosion. However, there was conflict between English Nature, an environmental group concerned of the impacts to the sediment cell threatening the nature reserve further down the coast. Hamlets further down the coast would not be protected, not passing cost benefit analysis.
        
        Ultimately, the conflict ruled in English Nature's favor as the defences were not extended to the village, left at " no active intervention". This continues to be reviewed, but for now no active intervention continues in most areas, with localised protection when necessary.