Coastal management integrated and sustainable management


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Coastal management integrated and sustainable management

  1. 1. The Holderness Coast, NE England Aims: Why is the Holderness Coast at risk from coastal erosion? What management strategies can be used to protect it? How successful are these management strategies
  2. 2. 1. Geology What factors put this coastline at such risk? 2. Fetch 3. Processes What are / could be the effects of this coastal erosion?
  3. 3. Holderness Coast: N.E England Most rapidly eroding coast in (29 villages lost since Roman times) Rapid coastal erosion (~2m /yr) •Geology: (soft Boulder Clay) this is also a problem as it erodes to form small clay particles which are transported out to sea rather than forming beaches to protect the coast. (Although more resistant chalk at Flamborough Head to the North) •Fetch: Currents circulate around the North Sea from the . This 5000km fetch produces high energy destructive waves. The North Sea is also enclosed and deep which means waves reach cliffs without being weakened by friction from shallow beaches and have no where to disperse there energy. •Processes: Cliff foot (marine erosion/ transportation / deposition) and sub-aerial process (mass movement and weathering) erode the coastline.
  4. 4. Hard engineering •Hard engineering options tend to be expensive and short-term options. They may also have a high impact on the landscape or environment. The table shows the most common hard engineering solutions     
  5. 5. Soft engineering Soft engineering options are often less expensive than hard engineering options. They are usually also more long-term and sustainable, with less impact on the environment. There are two main types of soft engineering. 1. Beach nourishment • This replaces beach or cliff material that has been removed by erosion or longshore drift. • The main advantage is that beaches are a natural defence against erosion and coastal flooding. Beaches also attract tourists. • While it can be a relatively inexpensive option it requires constant maintenance to keep replacing the beach material as it is washed away. 2. Managed retreat • This is where areas of the coast are allowed to erode and flood naturally. Usually this will be areas considered to be low value. • The advantages are that it encourages the development of beaches (a natural defence) and salt marshes (important for the environment) and cost is low. • While this is a cheap option, it will not be free as people will need to be compensated for loss of buildings and farmland. •
  6. 6. How are these management decisions made? • • • • • Cost Benefit Analysis: Environmental Impact Assessment: Feasibility Study: Risk Assessment: Shoreline Management Plan:
  7. 7. Sediment Cells in the UK The eroding Holderness Coastline
  8. 8. Coastal management along the Holderness Coast? Integrated Coastal Management • • Means that sections of the coast are managed as a whole, rather than by individual towns or villages. Coastal engineers now realise that actions in one place have effects in other areas. Shoreline Management Plans (SMPs) are used to manage smaller sub cell area. All local interest groups are consulted before taking one of the following options. 1. Do Nothing: e.g. let existing defences collapse 2. Hold the Line: e.g. keep the coastline where it is by using hard engineering 3. Advance the Line: e.g. build coastal defences further out to sea – breakwaters 4. Retreat the Line: e.g. allow the coast to erode back to a defined line The SMP for the Holderness Coast is: • • Hold the line in places of economic value – e.g. Gas pipe terminal at Easington and towns at Bridlington and Hornsea Do nothing in areas where nothing is worth protecting from erosion. Unprotected areas will eventually from bays. These will become more sheltered, and erosion should stabilise
  9. 9. Coastal management along the Holderness Coast? What are the positives and negatives of Integrated Coastal Management Positives •Combines hard engineering (for places of economic value needing a strategy of hold the line) with soft engineering which is more sustainable and long term for areas of lower value or with valued eco-systems. •They manage the coastline (sediment cell) as a whole so consider any consequences of management schemes on different areas of the coastline. •They take into account the views of many local interest groups, so should be of benefit to most. Negatives •It can be difficult and time consuming to consult lots of different players, with different priorities. •Hard engineering (holding the line) is expensive and can be short term. •Holding the line in one place can have increased impacts in other areas. E.g. Mappleton – rock groynes leading to increased erosion in Great Cowden. •Managed retreat (do nothing) is often unpopular, it can be seen as an ‘easy opt out’ and can be politically difficult to execute.
  10. 10. Sustainable coastal management: Abbotts Hall Farm, Thames Estuary Sustainable Coastal Management • • • • Sustainable coastal defence/management attempts to accommodate, copy or work alongside natural systems and processes, with ecosystems often playing a key role. Typically such approaches are small scale, localised and bottom-up or community driven. They have the advantages of being environmentally friendly, sometimes cheaper and longer-lasting. Consideration needs to be taken so that schemes are compatible with adjacent coastal areas. E.g. Thames Estuary, Abbotts Hall Farm, Essex Coastal Realignment can be controversial – as existing sea defences are left to collapse (do nothing approach). – Salt marsh ecosystems are encouraged. This deliberate flooding helps create valuable habitats and can provide a natural defence to flooding – It also saves expenditure on failing sea walls
  11. 11. Sustainable coastal management: Abbotts Hall Farm, Thames Estuary What are the positives and negatives of Sustainable Coastal Management Positives •Ecosystems playing a key role. E.g. Salt marshes are allowed to develop. This provides an ecosystem / habitat •Typically such approaches are small scale, localised and bottom-up or community driven. Therefore local people have ownership over the schemes. •They are environmentally friendly. •Often cheaper (it costs very little to retreat the line – i.e. just the cost of low value farm land) •Often longer-lasting. E.g. with rising sea levels the area will eventually flood. Introduction of salt marshes provide a longer term, natural solution to this Negatives •Coastal realignment may be controversial. It involves ‘retreating the line’ and is often viewed by local residents as the do-nothing and easy opt out. Politically can be difficult to execute. •Consideration needs to be taken so that schemes are compatible with adjacent coastal areas. •Can only be used in areas of low value land as it does not hold the line. E.g. protect property. •It is often only small scale so does not contribute to large areas of the coast.