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CLIFFS launch meeting 26 October 2005, Holywell Park, Loughborough - PowerPoint PPT Presentation

CLIFFS launch meeting 26 October 2005, Holywell Park, Loughborough University Climate change impacts on coastal cliffs: accessing and using meaningful data Dr Paul Fish CGeol FGS Dr Roger Moore CGeol FGS FICE Halcrow Group Ltd, Engineering


  1. CLIFFS launch meeting 26 October 2005, Holywell Park, Loughborough University Climate change impacts on coastal cliffs: accessing and using meaningful data Dr Paul Fish CGeol FGS Dr Roger Moore CGeol FGS FICE Halcrow Group Ltd, Engineering Geomorphology

  2. Holbeck Hall Hotel, Blackgang 1995 Scarborough 1993 A3055 Isle of Wight Undercliff 2001

  3. Shanklin Cliff failure 2001 - 8 injured Nefyn, April 2001

  4. Recession Rates m/yr Seven Period Birling Gap Sisters 1874-1909 0.48 0.64 1909-1926 0.76 1.41 1926-1975 0.96 0.91 1975-2005 1.25 1.12 Beachy Head Cliff Falls: Lighthouse Jan 1999 (100k tons) Devil’s Chimney Apr 2001 (50k tons)

  5. Reactivation of relict landslides, Isle of Wight # Major Period Events 1839-1880 8 1881-1920 6 1921-1960 12 1960-2005 20

  6. Ventnor Undercliff, Isle of Wight �������� ����������� (mm) ���� ��� ��� ��� ��� � ���� ���� ���� ���� ���� ���� ���� ���� ���� ���� ���� ���� ���� ���� ���� ���� ����

  7. Climate change,cliff erosion hazard & risk Likely Future Scenarios: Key Parameters: • Increased coastal • Historical recession rate erosion and cliff retreat ? • Landslide event frequency • Higher winter rainfall, • Sea-level groundwater levels and • Winter rainfall coastal cliff instability ? • Sediment budget (beach) • Reactivation of relict coastal landslide • Shoreline protection systems ? � There is a great need for fundamental research into the controls and future drivers of coastal cliff instability and erosion – there are very few historical case studies or analogues to inform future projections of cliff behaviour and recession under various climate change scenarios

  8. UKCIP02 - Climate Change Predictions • Four regional climate change scenarios for the UK (50km grid) based on IPCC global model Climate change predictions to 2080: � Temperature +2°to 3.5° C � Summer rainfall & soil moisture -40% � Winter rainfall +30% � Increased frequency of storms � Sea level in SE +26cm to 86cm � Extreme sea level 10 to 20 times more frequent

  9. UKCIP02 – regional predictions Resolution: 50km grid Predicted change in temperature Predicted change in rainfall

  10. Cliff sensitivity to climate change ��� 0�;���<�����3���� 0�;���+��,!��,! +��!���� ��� 7����������- 4!��;������ 2��0�;���,� :�;)������ ����� �������!�"#������ ��� 8������- 3�����!�$�� +��,-.��. 0�,,��1��3���1� /!��0������) ��� ����1��� 0�,,��1� ��� ��� 6))���7������ 6))���+��,!��,! �� �������!�"#� ��� ���-5��+�� #$���� /!��8�,!���9�:���� +������+�� �����"#� ��� 2��0�;���,������;���2������ 2���)!����3�$� 4!�����5��+�� ��� ���%�����&��'������(�)���&������� ��&�����*������� � � �� ��� ���� ��������������������� � There are issues applying the UKCIP02 quarterly predictions as they may not exactly match other established relationships such as this

  11. Available data and information Key Factual Data: Example Derived Data: • Satellite data • Geomorphology maps • Topographical maps • Erosion risk maps • Aerial photographs • Sediment transport • Elevation data (DEM) • Climate change • Morphological maps predictions i.e. rainfall • Site-specific data and sea level rise • Hydrodynamic monitoring • Anecdotal records • Observational records

  12. � ������� ������� � � �������� �������� � �������� �������� ���������� ���������� � ���������� ���������� � � ���� ����� � � �������� �������� � ���������� ���������� � � ������������� ������������� � �����!������� �����!������� ������ ������ ������������������������������ ������������������������������ ���������������������������� ���������������������������� ���������������� ���������������� ���� ����

  13. OS mapping 1860 to present • All map data is georectified Oldest mapping from mid 19 th • – Potential problems with projection of Century maps pre- and post introduction of – Possible survey error the National Grid (1940s) – Problems of interpretation of – Problems of distortion of old paper landforms maps

  14. Aerial photographs – 1941 to 2002 • Georectification uses x and y from • Aerial photographs should be large-scale OS maps referenced to the National Grid • Coastal areas often have few mapped • Orthorectification uses x, y and z permanent features (roads, buildings, coordinates from digital elevation field boundaries) data (e.g. LiDAR, IfSAR) • In all cases error of fit (RMS) needs to • Errors are concentrated at the coast be calculated and understood

  15. Regional assessments Digital orthophotograph (19cm x, y) LiDAR ground model (2m x, y; 25cm z) Processing issues: Need to compare repeat LiDAR datasets derived from the same processing algorithms which may change Synchronised aerial surveys avoid problems with historical data

  16. Site-specific assessments Method: • Detailed field mapping and interpretation of aerial photographs Accuracy: • Scale limited up to ±1m Geomorphology • Defines nature, extent and past behaviour of unstable ground • Used to rationalise subsurface investigation and monitoring • Framework for management of complex coastal landslides Cliff Behaviour • Requires periodic updating

  17. Investigation, survey and monitoring Real-time § mm Accurate §

  18. Modelling approaches and uncertainties • Extrapolation from historical data: – Historical rate of change = Predicted rate of change • Empirical modelling of shoreline retreat from sea-level rise: – 2D approaches, Bruun rule, sediment budgets • Behavioural process-response models – 3D interaction between coastal process and landforms • Deterministic modelling – Uses historical rates of change and judgements about future uncertainties • Probabilistic modelling – Permits variability in predictions and handling of uncertainty

  19. Strategic scale – FutureCoast projection • Gather an appreciation of the various components of the coastal system, their dynamics and influences; • Identify behavioural characteristics and systems; • Determine dominant controls, influences and resultant pressures. This understanding was then used to make forecasts of the large-scale future evolutionary trends, and from this to predict shoreline response for specific areas.

  20. Deterministic modelling 80 Profiles used mean 70 for analysis maximum 60 Cliff House Hotel 50 (m) 40 30 20 10 0 Naish Cliff M arine Farm Barton Naish Farm House M arine Drive Becton Court Hotel Drive West Bunny East Historical recession data can be used to Cumulative recession of Model future change. Projections can take cliff units: 1940-2001 account of error in data, sea-level rise, sediment budgets and degradation of coastal defences

  21. Probabilistic recession modelling New Defra/EA R&D project FD2324 Risk Assessment of Coastal Erosion Aims to provide an approach for probabilistic assessment of coastal erosion for LA to deliver Defra high level targets

  22. Conclusions • Cliff instability and erosion increasing • Climate change is a key driver • Good historical data available • Limited site monitoring data • Few good case studies and analogues • Projections of cliff behaviour rely on historical data • Modelling approaches not widely applied in UK • Need fundamental research on climate change impacts on cliff behaviour and erosion potential

  23. Acknowledgements Andrew Bradbury (NFDC) Robin McInnes (IWC) Geoff Davis (WDDC) John Riby (SBC) SCOPAC Mark Lee

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