Overstrand To Cley

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Overstrand To Cley

  1. 1. <ul><li>Coastal Processes </li></ul><ul><li>Management Strategies </li></ul><ul><li>Sustainability Issues </li></ul>Coastal Study
  2. 2. The North Norfolk Coast
  3. 3. Study Sites Sheringham West Runton Cley-next-the-Sea Overstrand Cromer
  4. 4. Factors Affecting Erosion <ul><li>Geology </li></ul><ul><li>Sub-aerial Processes. </li></ul><ul><li>Human Influence </li></ul><ul><li>The Sea </li></ul>
  5. 5. Distance over which waves have to build up NE 600km Denmark N 4100km Arctic Fetch
  6. 6. Cross-section of a typical cliff in North Norfolk Glacial Till 250 - 450 Ka West Runton Freshwater Peat Bed 650 Ka Chalk 60 - 70 Ma Weybourne Crag 1 - 2 Ma Geology
  7. 7. Sub-aerial Processes S aturation U ndercutting S lumping T ransportation S.U.S.T.
  8. 8. Erosion Consequences Loss of 1 metre of cliff annually <ul><li>Not Uniform </li></ul><ul><li>Coastal Variations </li></ul>Effects <ul><li>Destruction of Property </li></ul><ul><li>Loss of Livelihood </li></ul><ul><li>Habitat Loss </li></ul>Overstrand Hotel
  9. 9. Coastal Defences Angled Sea Wall Groynes Flat Sea Wall Rock Armour Groynes Rip-Rap
  10. 10. Beach Nourishment Revetments Bore Pipes Gabions Shingle Ridge Coastal Defences
  11. 11. Sustainability <ul><li>Bruntland (1987) </li></ul><ul><ul><li>“ meeting the needs of the present without compromising the ability of future generations to meet their own needs” </li></ul></ul><ul><ul><li>Example : </li></ul></ul><ul><ul><li>Groynes are made of wood from rainforests. </li></ul></ul><ul><ul><li>Therefore we chop down forests to make groynes. </li></ul></ul><ul><ul><li>Eventually this deforestation leads to global warming and higher sea levels. </li></ul></ul><ul><ul><li>Consequently there is an increased need for groynes. </li></ul></ul>
  12. 12. Costs and Payments <ul><li>Norfolk coastline is 74km long (Hunstanton to Lowestoft) </li></ul><ul><li>34km of it is being protected by sea defences </li></ul><ul><li>If all defences were taken out and re-built today cost would be £70m </li></ul><ul><li>Annual maintenance budget of £280,000 </li></ul><ul><li>Sheringham spent £5.25m on defences between 1995 and 2000 </li></ul>
  13. 13. So Who Pays? <ul><li>DEFRA ( Department for the Environment, Food and Rural Affairs) </li></ul><ul><li>Can pay up to 75% of cost for sea defences </li></ul><ul><li>Only contribute 55% in North Norfolk </li></ul><ul><li>Local District Councils </li></ul><ul><li>Pay the rest, but can get a ‘supplementary credit agreement’ loan </li></ul><ul><li>As they pay the majority, DEFRA decide where the defenses will go </li></ul>
  14. 14. 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?
  15. 15. Shoreline Management Plans <ul><li>“ Management of one area of coast may have an adverse impact on other areas” </li></ul><ul><li>The UK coastline is divided into management cells and sub-cells corresponding to changes in longshore drift </li></ul><ul><li>Norfolk is divided into sub-cells 3a and 3b, with the division roughly at Sheringham </li></ul>
  16. 16. Advance The Line Managed Retreat Do Nothing Hold The Line S.M.Ps. Four Strategies
  17. 17. <ul><li>Tomorrow </li></ul><ul><li>Meeting time . . . </li></ul><ul><li>Structure of the day </li></ul><ul><li>Weather </li></ul><ul><li>What you need to bring . . . </li></ul><ul><li>1. Weather dependent: waterproofs, warm clothing, extra drink, sun cream </li></ul><ul><li>2. Essentials: work stuff, comfortable shoes </li></ul><ul><li>Citizenship – </li></ul><ul><li>“ take nothing but pictures, leave nothing but footprints” </li></ul>
  18. 18. Cley-next-the-Sea <ul><li>Population 600 </li></ul><ul><li>Fishing industry </li></ul><ul><li>Freshwater marsh (SSSI), owned by NWT, prone to flooding </li></ul><ul><li>Starting point of shingle spit </li></ul>
  19. 19. Sheringham <ul><li>Population: 7,500 </li></ul><ul><li>2nd biggest tourist resort in North Norfolk after Cromer </li></ul><ul><li>Steam railway is a major attraction (125,000 per year) </li></ul><ul><li>Heavy sea defences </li></ul>
  20. 20. West Runton <ul><li>Population: 800 </li></ul><ul><li>Built up around fishing industry </li></ul><ul><li>Fantastic geology (SSSI) </li></ul><ul><li>Locally important as a Rocky Shore </li></ul>
  21. 21. Cromer <ul><li>Population: 8,000 </li></ul><ul><li>“ Gem of the North Norfolk coast” </li></ul><ul><li>Many sea defences because of weak geology </li></ul><ul><li>Cliff-top settlement </li></ul>
  22. 22. Overstrand <ul><li>Population: 1,100 </li></ul><ul><li>Highly exclusive tourist resort </li></ul><ul><li>Site of Clifton Way project - experimental sea defences </li></ul>
  23. 23. Flat Sea Wall <ul><li>Reinforced concrete </li></ul><ul><li>Maximum life span 100 years </li></ul><ul><li>£3,000 per linear metre </li></ul>
  24. 24. Angled Sea Wall <ul><li>Reinforced concrete </li></ul><ul><li>Maximum life span 100 years </li></ul><ul><li>£5,000 per linear metre </li></ul>
  25. 25. <ul><li>Granite from Norway </li></ul><ul><li>£1-3,000 per boulder (depending on size) </li></ul><ul><li>100 + years life span </li></ul>Rip-Rap
  26. 26. <ul><li>Tropical Greenhart wood </li></ul><ul><li>30-40yr life span </li></ul><ul><li>£1,000 per linear metre </li></ul>Groynes
  27. 27. Rock Armour Groynes <ul><li>Made from Rip-Rap </li></ul><ul><li>More effective at stopping longshore drift than wooden groynes </li></ul><ul><li>£1,250 per linear metre </li></ul>
  28. 28. <ul><li>Were made from iron, now flexible plastic </li></ul><ul><li>£ 120 per metre </li></ul>Bore Pipes
  29. 29. Beach Nourishment <ul><li>Movement of beach material from one beach to another </li></ul><ul><li>Longshore Drift transports it along shore </li></ul><ul><li>Replenished each year </li></ul><ul><li>£10 per m 3 </li></ul>
  30. 30. Shingle Ridge <ul><li>Beach material bulldozed into a barrier </li></ul><ul><li>6 Month lifespan </li></ul><ul><li>£40,000 maintenance each year </li></ul>
  31. 31. <ul><li>Tropical Greenhart wood </li></ul><ul><li>30-40yr life span </li></ul><ul><li>£1,500 per linear metre </li></ul>Revetment
  32. 32. <ul><li>Cages filled with beach material </li></ul><ul><li>5-10 year life span </li></ul><ul><li>£50 per cage </li></ul>Gabions

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