Cover lesson · Geography · Year 10 · Intermediate

Improving a coastal erosion infographic: Bae Eithin

DCF: Producing → Evaluating and improving digital content

Name: Class: Date:

Cover teacher: you need no subject knowledge

Print: this sheet, one per pupil, and the stimulus sheet “Bae Eithin: the coastal change pack”, one between two. No computers are needed. Pupils need a calculator, a ruler and coloured pencils. The data are also in bae-eithin-cliff-retreat.csv if you are in a computer room.

Run: 5 min pupils read the pack in pairs · 12 min Step 2, retreat rates · 8 min Step 3, the rock armour · 12 min Step 4, the fault grid · 15 min Step 5, the redesign, alone · 5 min Step 6, justify two choices. Total 57 minutes.

Collect: this sheet. This lesson practises GCSE Geography Unit 1: Our Physical and Human World, topic 1.2 Changing coastlines (1.2.5, human and physical factors that affect the rates of coastline change), with the GIS, calculation and graph skills in Appendix B of the WJEC specification. The place is invented.

What you are doing

Bae Eithin is a bay with soft clay cliffs between two hard sandstone headlands. A volunteer turned real-looking GIS measurements into an infographic for the community council website, and residents are worried and confused. You will work out how fast each part of the coast is really retreating, find what the infographic gets wrong, and redesign it so that residents get a clear and honest picture.

Step 1: read the pack

Read all six sections of the stimulus sheet. Key words:

Transect: a straight line at right angles to the coast, along which you measure.
Retreat: the cliff top moving inland because of erosion and mass movement.
Rate of retreat: how many metres the cliff top moves inland each year. Rate = metres retreated ÷ number of years.
Rock armour: large boulders placed at the foot of a cliff to absorb wave energy. It is a form of hard engineering.

Step 2: how fast is each part of the coast retreating?

Use Table 1. Retreat = distance in 1946 − distance in 2024. Rate = retreat ÷ 78. Give rates to 2 decimal places.

Transect	Rock	Retreat 1946 to 2024 (m)	Rate (m per year)
T1	Sandstone
T2	Sandstone
T3	Boulder clay
T4	Boulder clay
T5	Boulder clay
T6	Boulder clay
T7	Sandstone

(a) Work out three mean rates. Show your working.

Mean rate of retreat	m per year
The three headland transects (T1, T2, T7)
The four bay transects (T3 to T6)
All seven transects

(b) Describe the pattern along the coast from T1 to T7, using figures. Then explain it: why do the headlands retreat so much more slowly than the bay?

Step 3: did the rock armour work?

The rock armour was placed at T4 in 2006. Work out the rate before and after.

Transect	Rate 1946 to 2006 (retreat ÷ 60)	Rate 2006 to 2024 (retreat ÷ 18)
T4 (rock armour)
T5 (just south of it)

The infographic says: “The rock armour has made things worse.” Is that true, false, or half true? Use your figures, and use the words longshore drift and wave energy to explain what has happened at T5.

Step 4: what is wrong with the infographic?

Find five faults in Figure B. Use the comments in section 6 as feedback from the audience. For each fault, say why it matters to a resident and how you would fix it.

	Fault (what is wrong)	Why it matters to a resident	How to fix it
1
2
3
4
5

Step 5: redesign it

Sketch an improved infographic in the box, in pencil first. It must have:

a headline that is accurate and calm, with a correct figure;
a bar chart of retreat 1946 to 2024 for all seven transects, in order from T1 to T7, with the axis starting at 0, a title, axis labels with units, and headland bars shaded differently from bay bars;
a small map with a key, a north arrow and a scale bar, using colours or line styles that a colour-blind reader can tell apart;
one sentence on the rock armour that is fair to both T4 and T5;
a source line: where the data came from, the years, and how accurate they are.

Step 6: justify two choices

Pick two design choices you made. For each, say why it suits the residents of Bae Eithin, and give one disadvantage it still has.

Step by step

5 min Read the pack with a partner. Look closely at Figure B.
12 min Step 2: fill in the table, the three means, and describe and explain the pattern.
8 min Step 3: the before and after rates, and your verdict on the rock armour claim.
12 min Step 4: five faults, each with why it matters and a fix.
15 min Step 5: sketch the new infographic on your own.
5 min Step 6: justify two of your choices.

Success criteria

I can calculate rates of retreat correctly and use them to describe a pattern along the coast.
I can explain the pattern using rock type and the effect of hard engineering, with correct geographical words.
I can find the faults in a piece of digital content and explain how each one could mislead its audience.
I can suggest and make improvements that fit the audience and purpose, based on the feedback the audience gave.
I can justify my design choices and explain the advantages and disadvantages of the output I created.

If you finish early

The nearest houses on Heol y Traeth are 20 m inland of the baseline wall at T3. If the T3 rate stays the same, roughly how many years until the cliff top reaches them? Why might the real answer be different?
The 1946 measurements are only accurate to ±1.5 m. Look again at the headland figures. What does this tell you about how confident we can be that the headlands have retreated at all?
Write the resident on Heol y Traeth a three-sentence reply that is honest and does not frighten them.