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Coastal Erosion on England's East Coast
INTRO
A short intro will go here.
Section 1 - Visual interpretation
A good place to start investigating the effects of coastal erosion is to look for places where there has been visible change over time. The National Library of Scotland provide an excellent tool for investigating change by overlaying historical maps of aerial images of the UK
To begin, select your cookies preference at the bottom of the screen, and close the initial pop-up.
The historic Ordnance Survey map will open over the town of Happisburgh, Norfolk, which lies on the East coast of England. This area is under great threat from coastal erosion.
Zoom in to the coastline using the scroll wheel, and using the 'Change transparency of overlay' slider, investigate the change which has occurred over time in this area.
If you find this map difficult to see due to its size, go to: https://maps.nls.uk/geo/explore/#zoom=15&lat=52.82276&lon=1.54113&layers=1&b=1
Using this transparency tool, investigate other areas of the UK that you think may be affected by coastal erosion. Move around the map by dragging the mouse.
Section 2 - Quantifying change
To investigate coastal erosion further, we can make measurements from maps to give the visual changes a meaningful value.
Using the mouse and scroll wheel, zoom to one of the areas of interest. Happisburgh in Norfolk will be used as an example however all instructions will apply to other sites.
Before making any measurements, we must again visually inspect what is shown by the map. Select the contents pane at the side.
You will see that the lines shown represent the historic cliff edge along that section of coast.
To find which date the line colour represents, click on all three Cliff Edge datasets in the content panel.
These lines have been sourced from historical maps, similar to those on the National Library of Scotland site. Investigate these cliff edge lines.
Some lines will be located further back than the actual edge. What can you determine that has happened at these areas?
What else surprises you about the rate change? (Hint; look for built structures along the beach)
The change over time can be investigated using the measure tool. Select the measure tool.
Make sure to use the distance tool rather than area (second option along).
Measure the distance from the 1976 cliff edge to the current cliff edge. Note your distance value down, either on paper or in a Excel document.
To get a more accurate indication of how the coast has changed, we can take multiple observations then find the average (mean value) of these measurements. Take a minimum of 10 measurements, then calculate the mean.
Using this mean, the future erosion can be predicted. For example, if we wanted to find where the coastline will be in 100 years time based on this historical data, we could perform the following calculation:
Future change = (Mean distance value ÷ 44 years) x 100 years
For instance, if the mean distance was 72.93m, the expected erosion in the future would be 165.75m further in land.
After calculating the future location of the coastline based on the 1976 coastline, repeat the step with at least one other historical cliff mark.
See how your estimates compare. Do they show similar trends? If not, why might they not? (Hint; look along the coast to look for human interventions such as groynes to explain your answer).
Enable the Future Coastline Prediction Layer for your site from the contents. If you measure from the current cliff inland, does you predicted distance fall within or close to the provided predicted area?
If not, think about how you sampled the data and if this will have affected the results or any other factors.
Section 3 - Further analysis
In the table of contents, turn off all current layers and turn on the 1965 Land use layer by ticking the box
Study the land use at this time.
Now turn on the 2014 land use layer. Can you see a relationship between the land lost to the sea and the land use type? Are certain land uses more at risk than others?
Now turn all current layers off and turn on ‘NCERM 2018’. This is the National Coastal Erosion Risk Map data provided by the UK’s Environment Agency.
One of the type attributes it contains is what government plans to do in the future with the coastline. There are three time periods used by the government in planning:
• Short Term (0 – 20yr)
• Medium Term (20 – 50yr)
• Long Term (50 – 100yr)
By default the short term plan is shown
You can check to see if the planned management type will change in the future by changing the symbology. Click the symbology button in the table of contents.
Next use to drop down to find either ‘MT_SMP’ or ‘LT_SMP’. This stands for medium term shore management plan and long term shore management plan. Short term is found under ‘ST_SMP’
Click done once you have selected the attribute you want to display. Do you think the future erosion you predicted earlier will occur based on the management plan in place?
This is the end of the exercise.