Coasts 5 - Evaluation Flashcards
If your data would be very different had you collected it at another time in the year, is your data inaccurate or unreliable?
Unreliable - accuracy is more about how precise your measurements were at the time, i.e. how close to the true value they were
Why might the bipolar results be somewhat unreliable
Because they were based on our perception at the time, and some of the criteria are very subjective.
Why was the cost benefit analysis more useful than the pebble lithology?
The overall enquiry question was about finding out if the benefits out weighted the cost of coastal defences so it was more useful to know whether this was true in economic terms by doing the cost-benefit analysis than finding out what types of pebble were found on the beaches.
Which of the following data collection techniques was qualitative?
Photographs, bi-polar, beach profile, cost benefit.
Photographs - all the others involved numbers.
How might the beach be different in the winter compared to May when we collected our data?
There are often more storms with destructive waves in the winter, so the beaches are likely to be smaller, with more material eroded
Why might systematically sampling of the beach for doing beach profiles be more appropriate than stratified sampling?
Systematic sampling enables you to see how the width and cross sectional area changes from south to north. With even gaps between data collection points it’s possible to see if there is a clear trend.
Why might stratified sampling of the beach for doing beach profiles be more appropriate than systematic sampling?
By choosing to measure the beach in front of different sea defences in different locations it makes it easy to identify whether there is a link between the type of sea defence used and the size of the beach,.
Give three reasons why you can be confident in your conclusion
The CBA clearly showed that in economic terms the cost of building the defences in each location was worth it - i.e. the cost of the defences was many times less than the value of the properties they protected.
The beach profiles clearly showed that the beaching is smaller in the south of Start Bay, with material being moved north due to longshore drift. As most of the settlements are in the south, and beaches are an effective form of coastal defence it’s obvious why sea defences are needed in the south ,… to protect settlements with small beaches.
The photographs showed clearly that there are a large number or properties very close to the sea and therefore at risk from flooding and erosion which supports the need for defences.
Give three reasons why you may need to question whether your conclusion was valid
We didn’t ask any residents their opinion about the sea defences. Therefore it’s hard to know what the social impact of the sea defences might have been.
Our bipolar survey of sea defences was subjective, based on our perceptions, which may not accurately reflect what the majority of people may think about how attractive they feel the defences are, for example.
We didn’t do an environmental impact assessment of the construction of the sea defences, so we don’t know what habits may have been lost and whether any species of plants and animals may have been affected … this may have highlighted the environmental costs of the defences.
