Comp 2 Topic 6 - Geographical Investigations- Physical Flashcards
What was your enquiry question?o
What impacts do different methods of coastal management have on the coastal processes and communities in Swanage bay?
Name the location that you visited.
Swanage bay
Explain why you chose your enquiry question/why was Swanage bay a suitable location for this question?
- Rates of erosion were high, Since 1985 the beach has narrowed by 20m. There was an 80% chance that Swanage’s sea wall would have collapsed.
- Projected losses were: 84 houses, 15 hotels and a main road at the cost of £10.5 million and the tourism of that area.
There was hard and soft management built in 2005
- 19 timber groynes
- beach replenishment (160,000 metric tonnes of sand)
- costed £2.2 million, in hopes it will provide a bigger beach
- there are communities that are being impacted both positively and negatively by the management
- lots of different types of management.
Write out the method to measure beach gradient.
(Quantitative data)
The sampling took place systematically. One location from in the ‘retreat the line’ management area and another in the ‘hold the line’ management area.
Method.
1)Place a ranging pole at the sea and Identify where the beach changed angle, place a ranging pole here.
2)measure the distance between each ranging pole in meters.
3)measure the angle between the ranging pole by using a clinometer to look from the top of the red line to the red line on the other ranging pole in degrees.
4)now look for the next change in gradient up the beach and repeat the steps above until your reach the cliff.
Write out the method for sediment size analysis.
(Quantitative data)
The sampling took place in one ‘retreat the line’ management area
And one ‘hold the line’ management area.
Method:
1)We set out a 10m by 10m grid on the sand
2)when then used a RNG to get two numbers. We would go along 2 meters and up to 4 meters on the grid and pick up a piece of sediment. 3)We measured the longest axis of the pebble using callipers in centimetres. We repeated this 10 times and got an average sediment size
4)we also measured the roundness of the 10 pebbles by judging the roundness of them on a powers scale where 1=very angular and 10=very round.
Two positive features of each method
Beach profile:
-Realistic sampling size. Not too big not too small.
-Compare how beach profile changes in the ‘retreat the line’ management area and the ‘hold the line’ management area
Sediment size:
Realistic sampling size. Not too big not too small.
-Compare how the sediment size and shape changes in the ‘retreat the line’ management area and the ‘hold the line’ management area
Questionnaire
-We used leading questions which meant that we as the questionnaires had little to do with the opinion
-we chose random people therefor was no bais
Explain two sources of error in each of your methods.
Beach profile
-The clinometer could be broken, giving inaccurate results
-Human error such as placing the poles or reading the clinometer inaccurately.
Sediment Size and characteristics
-Judging roundness is opinionated
-The rock may not have been picked at random. E.g biggest one chosen
Questionnaire
-The host may have been biased in who they picked to take questionnaire
-The sample size wasn’t big enough to represent the entirety of Swanage
How did you use sampling in each of your methods
Beach profiles:
Compared how the sediment size and shape changes in the ‘retreat the line’ management area and the ‘hold the line’ management area. So we can see how it changes from the upper coast to lower down. Allows us to see the effect of groynes in sediment size and shape
Sediment characteristics:
Compared how the beach gradient changes in the ‘retreat the line’ management area and the ‘hold the line’ management area. As in the retreat the line there was no beach nourishment.
Questionnaire:
Random sampling techniques which asked 10 people along the sea front of Swanage
What were the positive and negatives of your sampling strategies?
Pros:
Systematic sampling- allows us to see the changes as you go down the beach
Random sampling- there is no biased
Cons
Systematic sampling- health and safety, may not be able to access as ot is under a cliff
Random sampling- may not be targeting the right people to ask
Explain how the geology map of your location supported your investigation.
Swanage is a discordant coast. It is found in a (clay) soft rock bay with high rates of erosion and is surrounded by Durlston and Ballard headland which are hard rock (limestone/chalk)
Explain how the sediment cell transfer map supported your investigation.
Sediment is transferred through long shore drift along swanage bay from south to north. This makes it suitable as there is a dominant transport process of LSD and groynes in swanage. We can see how groynes affect LSD.
Describe how we measured how people viewed the impacts and success of coastal management.
Sampling- we asked 10 random people along the swanage coast
Method- we asked 7 closed questions using a bi-polar scale
Included
-are you concerned about coastal erosion
-do you think coastal defences have benefited businesses, shops and homes in swanage
-do you think coastal defences have benefited tourism
What was the conclusion we came to about the impact of management on beach gradient?
The ‘hold the line’ management of swanage bay through groynes and becah nourishment has created steeper and wider beaches than the ‘retreat the line’ section.
The width was 22 meters wide on managed beach compared to 19 meters on non-managed beach.
The height was 2.2m on managed beach compared to 0.5m on non-managed beach.
This is because the groynes have trapped sediment moving north along the swanage beach and has deposited material where groynes are leaving areas without management vulnerable.
What was the conclusion we came to about the impact of management on sediment characteristics?
The ‘hold the line’ management of Swanage bay has meant the sediment is larger than in the unmanaged ‘retreat the line’ section. The sediment is xcm long compared to xcm long, it is also more angular being powers 3 compared to powers 4 modal average in the unmanaged section .
The sediment is larger and more angular as it is trapped behind the groynes in the managed area and sediment is being added through nourishment. Also the cliff is collapsing in the unmanaged area adding small sand particles onto the beach, making the sediment smaller.
What was the conclusion we came to about the impact of management on communites?
Erosion is something that people were very worried about on the whole (66% very compared to 11% no). On the whole they said that management had positively benefited businesses, shops and homes in swanage (75%) and also 77% said it had been positive for tourism with only 4 and 1% saying no. This is despite 67% of people saying the hard management were unattractive to the town.
