- Quadrat – This is a hollow, flat metal square which we dropped every two metres up the beach to measure ground cover and also used it to help measure pebble size and roundness. For ground cover we dropped the quadrat and estimated the percentage cover inside it (i.e. 20% sand, 50% pebbles, 30% litter). When we came to measuring pebble roundness and the size of the pebbles we dropped the quadrat and measured only the pebbles inside it. We put the pebbles into certain groups for roundness, smooth, angular or in-between. For the size we measured in mm across its widest point.
- Ranging Pole – This was used to measure the height of the waves. To use it I stood in the sea (up to around 0.3 metres) and put the pole in, all the way to the bottom. To measure the height we saw where the water made a mark on the pole and measured that.
- Tape Measure – We used this to measure the distance up the beach; it showed us where to drop the quadrat (every two metres). One person held the end while another pulled the tape out to the required distance, reading off the measurements.
- Camera – I used this to take photos of any observations I made at both beaches, this gave me some extra information when I came back home, away from the site.
- Stopwatch – This was used to record data for wave frequency, this was measured from the time when the first wave broke until the time when the next one broke.
I think my techniques of measuring were the best, given the equipment I had. The pantometer could have been slightly un-accurate at times, for example, if the two legs were not 90 degrees, but it gave me some good results. The quadrat was a very efficient way of choosing stones to measure as it was at complete random, we walked all over the beach measuring the roundness and size at different distances. Also the ranging pole and stopwatch were the most accurate way of measuring the waves.
Data Presentation
In this part of my project I will display my data in several different ways, first I will show all the data I collected in tables, then after that I will put the data into beach profiles, using various methods to present my results.
Beach Profile Data:
Camber Sands - Set 1:
Ground Cover Data At Camber Sands:
Set 1:
Slope Profile Data:
Set 2:
Ground Cover Data At Camber Sands:
Set 2:
Slope Profile Data:
Set 3:
Ground Cover Data:
Set 3:
The beach at Fairlight was shorter than the one at Camber, so I could only measure 70 metres, instead of 100 like at Camber. Also, as I had more time at Fairlight, I measured wave frequency.
Fairlight – Set 1:
Wave Data:
Set 1:
Ground Cover at Fairlight Beach:
Set 1:
Slope Profile Data:
Set 2:
Wave Data:
Set 2:
Ground Cover Data:
Set 2:
Slope Profile Data:
Set 3:
Wave Data:
Set 3:
Ground Cover Data:
Set 3:
Pebble Size At Fairlight:
I am going to plot a line graph to show these results (this can
be seen on the page)
Pebble Roundness:
To measure the roundness of the pebbles I gave them a letter according to one of three categories; sharp, angular or in-between. I dropped a quadrat every five metres along the profile and randomly picking a stone from inside the quadrat, my results are shown below:
At Camber the process of longshore drift (illustrated below) takes sand away from the beach, with the only income of sand being from the River Rother, where it deposits sand in the Rye Bay, which is then blown onto the beach at Camber.
At Fairlight, just after the beach, there are cast revetments to catch beach material carried by longshore drift, so that it can be transferred back to the beach, I have included a sketch below:
Data Analysis
In this section I am going to identify any trends or patterns in my data. I will also explain what the data tells us about the study.
I will explain the theory of correlation and then using different tests, both graphic and statistical, I will find out if there is any correlation in my chosen data.
Correlation is the relationship between two sets of data, for example the amount of ice creams sold and the temperature on a specific day, in this case I would expect to find a link, but would use various processes to test my theory.
The sets of data that I am going to use are pebble size and distance up the beach. I am going to predict that the further down the beach the smaller the pebbles are and will now test my hypothesis in a variety of ways:
- Graphic : This is by using a scatter graph, plotting the points and then using a trend line to identify any correlation
- Statistical : This is by using Spearman’s rank correlation and entering numbers into a formula.
Scatter graphs are graphs in which you plot the points without joining them in any way and then add a trend line. The trend line (or line of best fit) is drawn in-between where the majority of the points lie (see below). The line of best fit will show whether the hypothesis is true, either being positive (going up), negative (going down) or no correlation (in this case it will either go horizontally or vertically). I have shown these three types of scatter graphs below.
Positive Negative
Anomalies such as this
one can happen, but when
drawing a trend line they
are ignored
Line of best fit
Plotted point
No Correlation
The scatter graph technique is a good visual way to see if there is any correlation as it is easy to see and relatively easy to produce. However it is not very accurate, you can only get an idea as the trend line is an approximation anyway. The line will give a good idea if the correlation is positive or negative (or even none at all) but if you need to be more precise it would be better to use a statistical method, in this case I will use ‘Spearman’s Rank Correlation’.
This is an equation that I can enter my data into to give a definitive statistical number between one and minus one, this can be shown on a number line:
-1 0 1
Each number can be interpreted as a scatter graph as illustrated below, with –1 being extremely negative correlation and +1 being extremely positive.
-1 0 1
The formula for Spearman’s Rank Correlation is as follows:
r = 1 - 6Σd2
n3 – n
r = Correlation
d = Difference in rank
n = Amount of data
I will now substitute my data into the equation:
The following is the ‘Spearman’s Rank’ formula but with my relevant information substituted in instead of the algebra:
r = 1 - 6 x 180
2744 – 14
= 0.604
This shows that there is a fairly strong correlation between these results.
When I put the results onto a number line I can see that there is a positive correlation.
-1 0 1
The results from this equation back up my scatter graph showing that there is positive correlation between the two sets of data, meaning that as you go further up the beach the pebble size increases.
From this data I can suggest geographical reasons why the distance up the beach affects the pebble size. The main reason that I can find is that the pebbles at the bottom of the beach are exposed to the sea more than the ones at the top of the beach, therefore getting eroded quicker. This is because the waves that crash onto the shoreline at Fairlight have an extremely large fetch, causing high wave energy and as the waves are destructive ones the pebbles nearer the bottom of the beach get eroded more than those at the top (due to the high, steep waves crashing and pulling the beach material downwards).
I shall also analyse the rest of the data that I collected starting with that of the first site I visited, Camber Sands. I can see that on the top of the dunes vegetation is the main type of ground cover. If you look at my beach profiles it shows when there is a dune, you can then look up to the percentage ground cover and should find that it is mainly vegetation, a good example of this is on profile 1 at 20m up the beach, where the percentage ground cover is 100% vegetation, this is because the marram grass grows on top of the dunes to hold them together.
The three sets of data for Camber Sands are similar, but sets 2 and 3 have more litter than set 1. This is most likely because of the sites at which I collected each set of data, the first set was collected a long way from the main path (an area where hardly anybody else would go) and then the 2nd and 3rd sets were collected about 50 metres either side of the main path (where more of the public would walk). This shows that the two sites that were near the main path had more litter on because of more people being there. I chose to take the three different sets of data in such different places to give me a good range of results and to try and be as accurate as possible.
The Fairlight sets of data are also similar. There were patches of sand on the percentage ground cover pie charts, these were where there were not many pebbles and so a sand patch had been created, you can see these on the photo on page 30 with the first beach profile for Fairlight. This is because of the destructive waves that have high wave energy causing a lot of shingle to be moved, and as it is not coming back onto the beach through longshore drift (due to the groyne at Hastings) an area of sand is created.
Conclusion & Evaluation
The two sites that I have studied in this investigation have to handle different types of erosion in different ways therefore making it hard to see which site is better managed. But, after all of the data I have collected in this investigation, I have come to the conclusion that coastal management is more effective at Fairlight than at Camber. This is because of some of the different schemes managers at Fairlight have used. The granite bolder-revetment, which was put on the beach at Fairlight, has extremely helped the protection of the cliffs, breaking up high wave energy so that the erosion is less.
At Camber, the fences around the dunes have helped keep tourists off, but not completely, as the evidence of the ground cover data proves that there is still litter around (which means there has been people there).
In this investigation I have studied the two sites in detail and come to a conclusion to agree with the original hypothesis. I realise that all my data cannot be 100% accurate, for example the pebble roundness could vary depending on the person that measures it. The data I recorded was collected as accurate as possible with the equipment that I could use, obviously if I had better equipment the results may have been slightly more accurate, but I think I would have still reached the same conclusion.
The investigation could be improved by taking wave data at Camber, however I did not have enough time so I couldn’t include this. It could be made more reliable if I were to take readings of the data on more than one day, for example once every month for six months, this would give me a better view of all the processes going on at the two sites.
However I think that I have conducted a fair and reliable investigation and as a result of this I got a good set of results, letting me find out more about the coastal management and how it is working at both sites. I have enjoyed doing this investigation and have gained a great deal from it, extending my knowledge of coastal management.
Bibliography
- The Collins English Dictionary 1986 Edition
