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The south-west coast of South Africa is a dynamic shoreline - NSC Marine Sciences - Question 4 - 2024 - Paper 1
Question 4
The south-west coast of South Africa is a dynamic shoreline. It experiences strong wave action that creates unique coastal formations. Smitswinkelbaai Cave (indicate... show full transcript
Worked Solution & Example Answer:The south-west coast of South Africa is a dynamic shoreline - NSC Marine Sciences - Question 4 - 2024 - Paper 1
Step 1
Describe TWO types of erosive forces.
Answer
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Hydraulic Action: This occurs when water and air are driven into openings, cracks, or potholes in the rocks. The force exerted by the movement of water creates pressure that can cause significant erosion.
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Abrasion: This process involves rocks or sediment rubbing against other rocks, causing them to be worn down into smaller fragments. This constant friction can lead to the smoothening of surfaces and further erosive activity.
Step 2
Explain the formation AND characteristics of a wave-cut platform.
Answer
The formation of a wave-cut platform occurs when:
- Waves erode the base of the cliff through constant hydraulic action, leading to undercutting and eventual collapse of the cliff above.
- Over time, debris is carried away by wave action, leaving behind a flat, wave-cut platform.
Characteristics of a Wave-Cut Platform:
- Typically, the platform is at an angle of approximately four degrees, allowing waves to wash up and down.
- The rock is often hard, and it may be interspersed with rock pools created during erosion.
- In some areas, there may be underlying rock that can influence the further development of the shore.
Step 3
Compare the structure AND effectiveness of both revetments and rock armour that are recommended to be used in this expansion.
Answer
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Revetments:
- Constructed from slanted stone, concrete, or wooden facings, they are designed to deflect wave action away from the shore.
- Though effective in preventing erosion, they require maintenance as they can be weakened over time due to overtopping.
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Rock Armour:
- Comprising large chunks of rock, often granite, rock armour acts by absorbing and dissipating wave energy, thus reducing the impact of direct force on the shoreline.
- While rock armour absorbs wave energy, it does not entirely prevent flooding and may shift or degrade with intense storms.
Step 4
Discuss the evidence of early humans found in and alongside Smitswinkelbaai Cave AND discuss whether an environmental impact assessment (EIA) would have value for this archaeological site.
Answer
The evidence of early humans living in Smitswinkelbaai Cave includes:
- Remains of mollusc shells, which provide insight into the diet of these early communities, including fish bones identified from nearby sources.
- The presence of dated artifacts and ecofacts that can help reconstruct the lifestyle and environmental adaptation strategies employed.
An Environmental Impact Assessment (EIA) would hold significant value for this archaeological site by:
- Identifying mitigation measures to protect the archaeological integrity while assessing potential risks caused by development projects.
- Ensuring that housing developments do not disrupt or destroy sensitive historical resources, thus preserving valuable cultural heritage.
Step 5
Recommend actions that aim to minimize the impact of the type of engineering approach to be used.
Answer
To minimize the impact of engineering approaches:
- Implement Integrated Coastal Zone Management (ICZM): This holistic approach balances environmental concerns with development needs, ensuring sustainable use of coastal areas.
- Conduct Regular Monitoring: Regular assessments of the coastal dynamics and effectiveness of engineering solutions can help identify potential issues early.
- Community Involvement: Engaging local stakeholders and the community in the planning and decision-making process helps to align development with ecological and archaeological values.