Physical Fieldwork - Durdle Door Beach

Key question

What coastal processes and features are evident at ‘Durdle Door’ beach in Dorset?

hypotheses to test (4)

• size of beach material decreases towards the sea

• beach material becomes more rounded towards the shore

• beach profile relates to wave type

• geology created the coastal features

data collection methods used (4)

• beach profile - using pantometer and tape measure to measure angled gradient of beach every 1m

• beach material survey - judge the roundness of 5 random rocks every 1m using a scale

• wave count - stopwatch for 1 min x 3 times

• field sketches

conclusion of field sketch

the hypothesis that coastal processes influenced coastal features is correct. erosion, eg hydraulic action, abrasion and corrosion, have shaped the arch and beach, while weathering has shaped the cliffs

pros (3) and cons (2) of field sketch as data collection

• no special equipment needed

• info can be added as annotations, so it is detailed

• can record a lot of info

• depends slightly on artistic ability - improvement would be to annotate photographs instead

• can be difficult to draw and write in poor weather conditions

how was the beach profile and sediment survey presented?

as a beach cross-section

conclusion of beach cross-section

hypothesis that beach profile is related to wave type was correct. wave type was destructive (12+ waves per min in the wave count). close to the shore, the beach goes down steeply, meaning the destructive waves eroded it.

hypothesis that beach material gets rounder towards the sea was correct. pebbles near the shore were very smooth and rounded, but nearer the chalk cliffs, the pebbles / rocks are quite jagged and irregular.

pros (4) and cons (4) of data collection methods - wave count, sediment survey, beach profile

• sediment survey was random, removing bias

• sediment survey and beach profile were systematic every metre - getting regular readings

• easy to carry out, and answered our hypotheses

• specialist equipment made data more accurate

• wave count - difficult to see where one wave ends and another starts

• human error - faulty pantometers

• sediment survey is subjective

• only a snapshot - profile and survey could be different at another time

pros (3) and cons (3) of data presentation as cross-section

• colour coded sediment roundness - easy to spot trends / interpret

• easily can see shape of beach

• added 2 lots of data to one data presentation

• a snapshot of beach

• had to exaggerate / manipulate data

• time-consuming to make