Physical fieldwork

Enquiry question of physical fieldwork

How effective are the coastal management strategies in Swanage Bay?

Location of physical fieldwork

Swanage Beach is located on the south west coast of the Uk, in the county of Dorset, on the isle of Purbeck.

the advantage(s) of the location(s) used for your fieldwork enquiry

Swanage beach was a suitable location for fieldwork as it had good accessibility, and within walking distance of a car park which was 360m from the pier. There was also a wide, flat area of footpath beside the beach to reduce risks of traffic and trip hazards. The beach was also wide, flat and sandy, and the water level was not too deep.

Why was your topic appropriate for a geographical enquiry?

it has coastal management strategies in place and we’re able to compare those strategies and evaluate, we also know that longshore drift is operating north to test the effectiveness of groynes.

Primary Data collection: Beach profile

Quantitative - Because if coastal management strategies were successful then beach nourishment, a strategy, should be present as it would create a wide and flat beach and can be evaluated by how flat and wide the beach is now compared to before.

Primary Data collection: Groynes

Quantitative - Because if the groynes are doing what we hypothesised, stopping longshore drift, then we should expect to see a larger drop on the north side of the groyne since sediment is being trapped on the north side and longshore drift moves sediment north.

Primary Data collection: Field Sketch

Qualitative Understand conditions of the day and key characteristics of the beach - the coastal management strategies that are present.

Secondary Data: geology map of Swanage and Dorset coastline

shows us the geology of the area and that swanage bay is made up of clay and sand which is softer than the surrounding rocks so it will erode faster and is in need of more protection.

Secondary Data: Swanage Bay Sediment Management Map

shows us the direction of longshore drift and that it is acting on the coastline, and that Longshore drift is predominantly moving in the direction of the north.

Justify one primary data collection method used in relation to the aim(s) of your physical geography enquiry - Beach Profile

We conducted two beach profiles at Swanage beach, one in the nourished area of the beach to the south of Swanage Bay and one at the north of the bay in the non-nourished area, north of the groynes. These beach profiles were useful as the results would allow us to see if beach nourishment has been effective at creating a wider and flatter beach in the south. Longshore drift moves in the direction of the prevailing wind which is coming from the South West, therefore we would expect sediment to be moving north. However the management strategies of beach nourishment and groynes would mean the beach is wider and flatter in the southern protected area of the bay

Justify the use of maps or photographs or field sketches in your physical geographical enquiry

We used a Geology map of Swanage and the Dorset coastline to help us understand the formation of Swanage Bay. we could see that Swanage bay is situated on a discordant coastline, and the geology here is soft clay and sands, between a layer of hard caulk to the north and hard limestone to the south. This was a good map to use as it helped us to understand the reason for the different rates of erosion and formation of the bay at Swanage due to coastal erosion, and the reason why the beach needs to be protected.

Suggest one reason why risk assessment was important when planning your enquiry

is essential when planning an enquiry to ensure that everyone helping to collect data, within a group, understands the range of hazards they could face and takes steps to reduce the likelihood of them occurring. For example, it was important that we wore appropriate footwear for rough and wet terrain on Swanage beach. This was to avoid trips, slips and injuries

Assess the effectiveness of your data collection methods - Beach Profile

used to evaluate the effectiveness of beach nourishment. It was conducted to show that the coastal management strategy, beach nourishment is effective beach nourishment should show a wide and flat beach. it was quantitative data so we’re able to see a prominent trend in data and compare data. However its weakness is that different people took turns using the clinometer and people may differ in their recording.

Assess the effectiveness of your data collection methods - Groynes upright measurement

used to evaluate the effectiveness of the groynes at stopping Longshore drift. for successful coastal management we would expect there to be a larger drop on the north side of the groynes since sediment is being trapped on the south side as the groynes stop longshore drift from sediment north.it was quantitative data so we’re able to see a prominent trend in data and compare data. However its weakness is that for it to be accurate you have to measure all the groins at the same time as it is dependent on the tide how many upright groynes can be measured.

data presentation method: GROYNE UPRIGHTS

used a bar graph to display the drop from the top of the groyne uprights to the sediment. For each groyne I drew two bars, one for the south side of the groyne, and one for the north side of the groyne. Although I measured the heights along each groyne from sea to sea wall, I calculated the mean height for each groyne to get an average to scale down the data I needed to present.  This enabled me to analyse the differences in height between groyne 1-18, but also compare the difference either side of each groyne, therefore showing changes in beach width across a wider study area, as well as assess the effectiveness of the groynes ability to prevent longshore drift. I colour coded the bars north and south, so that I could clearly see the differences for each groyne. 

data presentation method: GROYNE UPRIGHTS - strengths

able to see a visible trend with the data about the drop on each side as well as the side with the overall largest drop. Be able to compare trends and find anomalies in the data.

data presentation method: GROYNE UPRIGHTS - weaknesses

time consuming, presenting all 18 means it can be visually overwhelming.

data presentation method: BEACH PROFILE

used to present the beach profiles, were very effective in presenting the differences between the nourished beach in the south of the bay and the non-nourished beach north of the bay. The y axis represented the width of the beach, and the x axis represented the height/changes in gradient of the beach. I ensured I used the same scale for both so I could compare them. These graphs were easy to compare and analyse, as we used the same scale and therefore could easily identify which beach had more sediment, as the graph would be wider and steeper.

data presentation method: BEACH PROFILE - strengths

Easier to see the difference between the beaches in steepness.

data presentation method: BEACH PROFILE - weaknesses

Not using the same scale so it’s more difficult to visually see and the angles are really small. Does not show us the true width of depth of the beaches.

Beach Profile: results

The width of the beach is about 2.3 times larger than the non beach nourishment profile which has a width of 6m whilst nourishment has a width of 14m. There are anomalies in the beach nourishment profile, between 8m &10m is smaller than the angle before.

Beach Profile: Conclusion

The beach in the beach nourishment profile gradually gets steeper compared to the non beach nourishment which gets steeper immediately. shows coastal management success as the beach is wider and flatter.Shows coastal management has been effective as a nourished beach is wider and flatter is a sign of successful coastal management.

Groynes upright measurements: results

The side with the greater drop is the north side of the groynes out of the two sides, groyne 1: north side - 96cm drop and south side - 42cm drop, the drop increases as we move from the south to the north of the beach, e.g groyne 1 north side - 96 cm and groyne 18 north side - 138cm. Anomaly is groyne 5.

Groynes upright measurements: conclusion

The groynes are preventing longshore drift moving sediment up north, which is why we see a larger drop on the north side of the groyne and not as much sand is being deposited there compared to the south side. Because less sediment is being deposited in the north the majority is stopped by the groynes in the south hence why the drop is larger for groyne 18 compared to groyne 1.Shows coastal management has been effective as the groynes are preventing longshore drift so most of the sand is being deposited in the south and little in the north, which helps with beach nourishment as it further nourishes the beach.