Coasts Fieldwork

Question 1

How to measure beach profile/gradient?

Answer 1

1) Identify line of transect (straight line across beach 丄 to shore)
2) Place ranging pole of 2 points at 2 points between line
3) Place tape measure along line of transect, between poles
4) Have 2 persons of same height to stand at each point
5) Position clinometer on ranging poles, held at eye-level, align it with top of other person’s head
6) Read the angle where string crosses scale on protractor
7) Record data and repeat for each transact (regular 2m intervals)

Question 2

How to measure beach sediment size?

Answer 2

Using sieves ( For fine sediments. Calc % of sediments left at each sieve)
1) Identify line of transect
2) Collect 100g of sample along transect line
3) Pour sediments through set of sieves
4) Weigh sand retained in each sieve
5) Calculate % of sediments retained of each sieve
● Record data

Using a Quadrat ( To measure rounder and bigger sediments)
1) Identify line of transect
2) Place quadrat on beach
3) 10-15 samples randomly picked using random number generator
4) Measure long axes of each sediment with Vernier caliper and find average length
● Measure angularity of sediments (pebbles) using Power’s scale of roundness ( If Applicable)

Question 3

When and why choose systematic sampling?

Answer 3

● Use when Sufficient representatives available
How to carry out?
● Samples chosen at regular intervals (Spacing - 2m interval, Time - every 30 mins or at set timing, Numbered - every 5 persons)

Advantages
● Cover large area of study
● Simple to understand and carry out
● Reduce biasness

Disadvantages
● Seem more biased than random as not all have equal chance of
being picked, over/under representation (only large samples
chosen, only males chosen)

Question 4

When and why choose random sampling?

Answer 4

● Used when Whole population available for survey

How to carry out?
● Samples or locations chosen at no specific intervals (random
number generator, random number table, rolling dice)

Advantages
● Used with large sample population
● Simple and quick
● Reduce biasness

Disadvantages
● Poor representation of population (large areas not selected by random numbers)

Question 5

When and why choose stratified sampling?

Answer 5

● Used for subgroups of a survey
How to carry out?
● Samples divided according to characteristics (at berm where sediments are finer)

Advantages
● Better representation of total sample population that has known subsets
● Can use with random or systematic
● Allows for better comparison study between subjects

Disadvantages
● Exact size of subsets must be accurately determined
● Full information about subsets not available easily

Question 6

How to measure wave frequency?

Answer 6

1) Ranging pole on water’s edge
2) Use stopwatch to time duration of observation
3) Count number of waves breaking at ranging pole in 5 minutes
4) Find average number of readings to find mean wave frequency

Question 7

What are some safety precautions for measuring coast fieldwork?

Answer 7

• Surroundings,
  Stability of cliffs, Possibility of rock falls on foot of cliffs
• Consult tide tables in order to work at low tide
• Watch out of slippery rocks/uneven groynes
• Wear protective, BRIGHTLY coloured clothes -> easily visible
• Wear COVERED SHOES -> protect against sharp objects
• Check WEATHER CONDITIONS -> do not conduct in stormy weather
• Stay in PAIRS/groups -> can render assistance if needed

Question 8

How to measure longshore drift/movement of beach materials?

Answer 8

Near the water’s edge stick a ranging pole into the sand, throw an orange 1 metre away from water’s edge

Observe travelling path pattern of orange for at least 20 min using stopwatch

Stick another ranging pole into the sand where orange lands where orange lands after being moved by swash & backwash

Use measuring tape to measure distance between 2 poles + record

Identify direction where sediment moved by noticing 2nd pole in relation to 1st