Representation of data
The above graph proves that the more money spent on the sea defence systems the higher the structural effectiveness. However, there is one site that does not follow this pattern; at Moat Farm where there are gabions that cost merely £200 per metre have a very high structural effective rate of 8. It also shows that the most effective sea wall is also the most expensive. This is located at North Walney, proving my hypothesis to be correct again.
This graph shows that there is a definite relationship between the aesthetic effectiveness and the cost of the sea defence system. It shows that there is a strong positive correlation but again as it shows with the structural effective graph there is one abnormal result. Moat Farm does not fit the trend as it only costs £200 but has a relatively high aesthetic rate of 6!
This is a Spearman’s Rank table which shows the correlation between two variables. In this case these are the cost of defence system and the structural effectiveness. To work out how close the relationship between these two variables you have to use the following formula:
R = 1 - 6∑ D2
N3 – N
R = 1- 6X11 R = 1 – 66 R = 1 – 0.31 R = 0.69
216 - 6 210
The closer the R is the stronger the correlation. A perfect positive correlation would be 1.0. Using the cost of the defence system and the structural effectiveness as my two variables the correlation between them is high. It is a strong and positive correlation. This tells me that the cost of the sea defence has got a strong relationship with the structural effectiveness.
As it shows in the table above the site that is ranked number 1 in both variables is North Walney and in both variables the defence system situated at South of Walney is ranked bottom (6th). The defence system that has the biggest increase of ranking points is that in Moat Farm where it rises from coming 5th at the cost of the system to 2nd in the structural effectiveness.
This is my second Spearman’s rank table this time showing the correlation between the cost of the sea defence and the aesthetic effectiveness. You have to use the following formula work out how close the relationship between these two variables:
R = 1 - 6∑ D2
N3 – N
R = 1- 6X7 R = 1 – 42 R = 1 – 0.2 R = 0.8
216 - 6 210
It is illustrated above that the correlation between the cost of the sea defence and the aesthetic effectiveness is very strong and positive. R is only 0.2 away from the perfect positive correlation. This therefore tells me that there is a very close-knit relationship between the aesthetic effectiveness and the cost of the sea defence. Comparing this to the result of my first Spearman’s rank using the cost of the sea defence and the structural effectiveness for my data it shows me that the cost of the sea defence and the aesthetic effectiveness has a stronger correlation by 0.11. This may be only minor but it is significant. I have now learnt that the cost of the sea defence and the aesthetic effectiveness has got a better, stronger and more positive correlation compared to the cost of the sea defence and the structural effectiveness.
As it shows in the table above, North Walney again came 1st in both variables and South Walney appearing last again in both ratings. The site and sea defence that had the biggest increase of ranking points was Moat Farm coming 5th in the cost of sea defence ranking to coming 3rd for the aesthetic effectiveness.
Moat Farm
Kingfisher Factory
Bardsey
Walney Island
Rampside
Data analysis
My results proved that my hypothesis was correct because it showed that the more money that was spent on the sea defence system the higher was the structural and aesthetic effectiveness. However, as it shows in my results there is one result that is inconsistent. At Moat Farm the gabions that are used cost only £200 per metre but were nearly as effective as the fish tail groyne situated at North Walney that cost £5000 per metre! The gabions received a high structural effectiveness rating of 8. This is due to how solid and effective the gabions are. They also allow a lot of deflection and percolation of wave energy. Also, in the graph showing the aesthetic effectiveness compared to the cost of the sea defence again the system at Moat Farm did not follow the pattern. Moat Farm got a rating of 6, at only costing £200 per metre. Comparing this to Kingfisher factory where the sea defence system cost £1,000 per metre and got a poor aesthetic rating of only 4.
Excluding the result from Moat Farm, both scatter graphs above show a very strong positive correlation. The results showed that the most effective sea defence system that also happens to be the most expensive is fish tail groin that is situated at North of Walney costing £5,000.
Generally the more the sea defence cost, the better it looked and the more use it was. There is a clearer correlation between the cost of the sea defence and the structural effectiveness than that of the aesthetic effectiveness compared to the cost.
Evaluation
To make this study better I think I need to study a lot more sites to produce a large sample to use in my graphs and data. For my Spearman’s Rank tables to be really effective you need to use at least 15 pairs of ranked data however, I only used 6. To make my spearman’s rank data more effective I should have looked at a minimum of an extra 9 pairs of ranked data. Also, a comparative study would have been very useful as I would have had double the amount of results to analyse and double the amount of research. I would have looked at a similar rural coastline such as Eastern Britain as it has similar geology due to the availability of boulder clay.
These studies could have involved more detailed coast benefit analysis. This involves looking at all the hidden costs and potential benefits in a numerical way. Another analysis that would have been very useful in this study is that of waves coming in toward the coastal defence system. We should have worked out how effective they are towards the system because obviously you have to study waves to test effectiveness. A good hypothesis for a study involving this would be – the more destructive the wave the more the coastal system is eroded.
Several coastal research indicates that the only effective way of managing the sea level rise in a rural area is using a method called ‘planned retreat’ which involves paying compensation to households who lose their properties and also directing services like roads, cable and water courses. More recent research shows that in rural areas it is better to let nature take its course by allowing ‘natural realignment’ this is where some parts of the coastline are allowed to erode naturally where coastal defences are not maintained and so parts of the coast are eroded whilst other are built up by coastal deposition, sand dune systems and farming salt marshes.