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This question is based on the hypothetical scenario described below - NSC Marine Sciences - Question 5 - 2024 - Paper 1
Question 5
This question is based on the hypothetical scenario described below. Kwaaihoek is a coastal region found along the east coast of South Africa near East London. This... show full transcript
Worked Solution & Example Answer:This question is based on the hypothetical scenario described below - NSC Marine Sciences - Question 5 - 2024 - Paper 1
Step 1
Explain how dunes are formed.
Answer
Dunes are formed through a combination of natural processes involving the transport and deposition of sediment. Initially, sediment is brought to the coast from inland rivers by longshore drift, which moves sand particles along the shoreline.
As the wind blows over the dry, loose sand, it lifts and transports sediment particles, leading to the establishment of small mounds or 'embryo dunes.' Over time, these embryonic dunes grow in size as they trap more sand, creating larger dunes.
The sediment accumulates when the wind speed decreases, causing sand to fall and be deposited. These formations continue to grow and stabilize, creating a dynamic ecosystem that can survive under coastal conditions.
Step 2
Discuss the role vegetation plays in the formation of a stable dune ecosystem.
Answer
Vegetation plays a crucial role in the formation and stabilization of dune ecosystems. The roots of pioneer plants help bind sand together, reducing erosion and preventing the loss of sediment. These plants create a microhabitat that enhances soil fertility and helps in the establishment of secondary vegetation.
As the vegetation matures, it provides shelter for wildlife and contributes to the nutrient cycling within the ecosystem. Additionally, healthier vegetation cover reduces the impact of wind and water erosion, contributing to the stability of the dune structures.
Step 3
Describe the TWO different engineering approaches that can be used AND compare their effectiveness for this site.
Answer
The two engineering approaches that can be utilized to manage sand build-up are:
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Hard Engineering Approaches: These include constructing seawalls, groynes, and breakwaters. They are designed to resist erosion and manage sediment flow along the coast. While they can be effective in the short term, they may lead to increased erosion in nearby areas and often require significant financial investment and maintenance.
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Soft Engineering Approaches: This involves using natural materials like vegetation and geotextiles to stabilize dunes and mitigate erosion. These solutions are often less intrusive and more environmentally friendly. They maintain the natural aesthetics of the beach and can be more cost-effective in the long run.
In comparison, while hard engineering offers immediate protection, soft engineering is often seen as a sustainable and less damaging alternative that provides long-term benefits to both the environmental ecosystem and local tourism.
Step 4
Motivate whether it is important to conduct an environmental impact assessment (EIA) before deciding on the type of engineering approach to use.
Answer
Conducting an Environmental Impact Assessment (EIA) is essential before implementing any engineering approach. The EIA helps identify potential environmental risks and assesses how the proposed structures will affect the local ecosystem.
This process allows for informed decision-making that balances economic needs with environmental sustainability. It also provides recommendations to mitigate adverse impacts, ensuring that the project does not harm the delicate dune ecosystems. Ultimately, conducting an EIA fosters transparency and community involvement, as it allows local residents and stakeholders to voice concerns.
Step 5
Justify whether constructing an engineering structure would benefit the local municipality.
Answer
Constructing engineering structures could provide significant benefits to the local municipality by improving access to tourism sites, potentially leading to increased revenue from tourism activities. However, it is crucial to consider the long-term environmental implications that these structures might bring.
If managed well, structural interventions can enhance the coastal landscape and protect local infrastructures from erosion and flooding. This project could also create jobs and stimulate economic growth; yet, poor planning could lead to environmental degradation and harm local biodiversity, which would negate these benefits.