This page is intended as an appendix to the sediment segmentation model and the migration chart.
Twice-yearly monitoring of cliff loss under the present system began in 2003, and information on beach contour levels is available from 2008. Although the following table spans eleven years, there is a break where a survey was missed because of poor weather. In effect, averages are calculated using data from ten years.
A coastal length of 52.77km is covered, this being undefended cliff from Bridlington south to the neck of the Spurn peninsula (monitoring profiles 8 to 122/123).
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A: monitoring season.
B: number of monitoring profiles at which cliff loss reported.
C, D, E: percentage of coastal length occupied by high / intermediate / low beach.
F, G, H: percentage of profile sections opposite high / intermediate / low beach.
I, J, K: total cliff loss (landward recession in metres) at profiles opposite high / intermediate / low beach.
L: activity index (detail).
Averages for columns B and L are rounded.
Columns F to K relate to profiles counted in B.
high beach: beach level contour having a minimum of +2.5 metres OD extending for a few metres from the base of the cliff.
intermediate beach: beach level contour between +1.5 and +2.5 metres OD extending for a few metres from the base of the cliff.
low beach: beach level contour having a maximum of +1.5 metres OD extending for a few metres from the base of the cliff.
profile: the intersect of the cliff line by the monitoring line.
profile section: the lateral extension either side of a monitoring line, usually 500 metres in total. See data in detail (profiles).
The charts below are produced from the table.
It may be seen that, on average, a little over half the coastal length displays a high, or full, upper beach. Such a beach offers some protection against wave energy. In quieter weather, the high water mark often does not reach the foot of the cliff. The migration chart indicates distribution.
About two-thirds of cliff loss, whether expressed in terms of extent or amount, occurs where the beach is less than full. Around one quarter of loss is opposite a low beach.
The loss of cliff where beach is high would for possibly a greater part be a result of erosion lag. See direct and delayed erosion.
An example of beach level contours data, for April 2015, can be found at the East Riding of Yorkshire Coastal Explorer Interface (Layer List at toolbar right, then tick Beach Level Contours).
Locations of monitoring profiles may be viewed in satellite imagery as follows:
- load Google Earth
- right click Temporary Places > Add > Network Link
- at Link, insert
- click on Untitled Network Link
- Pins Pr1 to Pr123 mark cliff top positions of monitoring profiles
- Pins EP1 to EP120 mark locations of erosion posts (former system)
- circled dots mark cliff top positions in 2003
Place descriptions are supplied at data summary and coordinates (spreadsheet).
cliff loss data (menu)
more on East Yorkshire coastal erosion
Prepared by Brian Williams in August 2020.