Coast GI Flashcards
Longshore/Beach Drift : Task
Task :
To measure the longshore drift of a section of East Coast Park to determine what impacts longshore/beach drift
Longshore/Beach Drift : Equipment needed
Equipment required : Clipboard with Paper Soft pencil and eraser Stopwatch Float (orange or coloured cork) Measuring tape
Longshore/Beach Drift : Methodology
Methodology :
- Decide on an appropriate distance to measure longshore drift over, for example, 10 meters
- Lay out measuring tape close to water and mark start and finish points
- Place your float into water in the breakwater zone at the start point
- Observe and time the object’s movement across the pre-set distance over a specific period of 5 minutes
- Mark the location of the float at 20s intervals and trace its path
Measuring Beach Gradient : Equipment
Equipment needed : Measuring tape Compass Ranging poles Clinometer
Measuring Beach Gradient : Methodology
Methodology :
- Pick a transect line on the beach in your assigned cell
- Starting at the water’s edge of the beach, lay the measuring tape along the transect line across the beach. Ensure that the transect is at right angle to sea by undertaking a compass bearing on a landmark at the back of the beach. Make sure that you always work along the bearing.
- Place the ranging poles at both ends of a segment of the transect where the gradient is uniform. Ensure that the poles are vertical. Rest them on the surface/equal depth into the sand.
- The observer holds the clinometer next to top/agreed height on the ranging pole and sight the other ranging pole (held by another student) at top/agreed height/same height. Allow the clinometer to adjust to angle.
- Record the segment slope in degrees. Record uphill angles as positive (+) and downhill as negative (-). Record under ‘Remarks’ anything of interest along the segment slope. E.g. deposit of shells. Take photographs of these observations.
- The observer then proceeds to the ranging pole at the point where the gradient changes and sights onto the ranging pole placed at the previous point and repeats steps 1-4 until the end point of the transect line.
Measuring Sediment Size & Roundness : Equipment
Equipment needed : Measuring tape Clear ruler Particle size card Recording sheet Magnifying glass Chopsticks Plastic zip-lock bags Markers Quadrants (optional)
Measuring Sediment Size & Roundness : Methodology
Methodology :
- Choose locations of your vertical transect within the beach area your group has been assigned.
- Starting at the water’s edge of the beach, lay the measuring tape along the transect line across the beach. Ensure that the transect is at the right angle to sea.
- At intervals of 2 meters, use a chopstick to mark each 2 meter point. At each point, take a photo of the sediments with a reference object for scale. Make sure the same object for scale is used throughout all the photos, and the photo has to be taken from the same angle.
- Select a spot next to the chopstick and sweep away the surface layer of sediments. Use a quadrant to select sediment for sampling. If there is no quadrant, place your foot on the selected spot. Select at least 10 surface pebbles that are touching your food in a systematic way. Using a particle size card, measure and record the length of the longest axis of each person. Calculate the average pebble length.
- If you do not have plastic sheets to place your sediments, you can use dry leaves to lay your sediments on it
Identify the range of size that most particles fall into, and then identify a size range that would represent the range of sizes present. If larger sized grains dominate then it is coarse-grained and if smaller then fine-grained
- Using the particle size card, make observations on how well the sediments are sorted. Make use of the magnifying glass to determine the best-fit sorting category. If all or most of the sediments are about the same size, then well-sorted. There is quite a bit of variation in sediment size, then poorly-sorted.
- Determine the average roundness and the shape of the sediments by comparing the sediments with the angularity chart in the particle size card. Also make use of the magnifying glass.
Record all the observations in the table below. Repeat steps 4 - 6 at each interval.
- After recording the data, collect a sample of sediments at each interval into separate zip-lock bags. Label the zip-lock bags according to the distance from the sea.
- Compare the sediment size and sorting based on distance from sea to see if there are any general patterns.
Measuring Sediment Size & Roundness : Limitations
Limitations:
- Varying tidal conditions can affect access and safety. It can also affect the results of sediment analysis across your vertical transect
- Different groups of students may actually get different sediment analysis based on the vertical transect the choose - e.g. if the choose nearer to the breakwaters
- Measuring 10 surface pebbles may not be reliable enough to determine average mean grain size
- Judgment of the pebble may vary from person to person creating subjectivity
- Anything which may affect the results should be noted for example recent storms or management structures which may alter the composition of beach materials
Measuring Sediment Size & Roundness : Theory of Methodology
The accuracy you apply to collecting data makes the interpretation and the conclusions more or less valid
Coastal Management / Protection Strategies : Methodology
- In this section, you will be required to determine the effectiveness of the coastal protection strategies at East Coast Beach
- Recall what coastal management strategies there are and how they protect the coast from erosional processes
For the attribute survey interviews : you may move around but do not venture beyond until it is time for the next activity - Always move with your group or in pairs. For the interviews in the last part of this activity, do not conduct the interviews on your own but assign your respective “Interviewer” and “Data recorder” roles in your group and conduct them
Weather Tracker : measures different elements of the weather
- Ensure the weather tracker is working - switch it on. If it is not working, check the battery
- Use the up and down arrows to scroll through options until you see wind speed and wind direction
- Remove cover
- Hold the weather tracker in a place where the wind will not be obstructed which would cause inaccurate readings. Examples include your body, buildings and trees.
- Hold the weather tracker above your head
- Wait until the readings on the digital display stabilize
- Take reading
- Wait one minute and repeat 3 times
- Record the average
Measuring Wave Frequency : Equipment
ranging pole & stop watch
Measuring Wave Frequency : Methodology
- Place the ranging pole close to the shore at the point where the waves break
- Using the stopwatch count the number of waves that pass the ranging
- Record this data in the table
- Wait one minute and repeat 3 times
- Record the average
- High frequency - 10 to 14 waves per minute
- Low frequency - 8 to 10 waves per minute
Wind Vane
- Hold the wind vane in a place where the wind will not be obscured which would cause inaccurate readings (E.g. body, buildings and trees)
- Hold the wind vane above your head
- Record the direction the wind vane points to. This shows the direction the wind is blowing
- Wait one minute and repeat 3 times
- Record the average
Anemometer
- Hold the anemometer in a place where the wind will not be obstructed which would cause inaccurate readings (E.g. body, buildings, trees)
- Hold the anemometer above your head
- Wait until the readings on the digital display stabilize
- Take reading
- Wait one minute and repeat 3 times
- Record the average
