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Human activity impacts on surface processes - Leaving Cert Geography - Question C - 2017
Question C
Human activity impacts on surface processes. Examine this statement with reference to one of the following: - The impact of flood control measures on river process... show full transcript
Worked Solution & Example Answer:Human activity impacts on surface processes - Leaving Cert Geography - Question C - 2017
Step 1
The impact of flood control measures on river processes
Answer
Flood control measures, such as the construction of dams and levees, have profound effects on river processes. These measures are designed to mitigate flooding, but they can disrupt natural river systems.
Impact on River Dynamics
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Altered Flow Regimes: Dams regulate water flow, leading to reduced peak flows during storms but increased base flows. This can change sediment transport dynamics, affecting the river's ability to erode and deposit materials.
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Sediment Trapping: Dams trap sediments that would normally replenish downstream ecosystems. This can lead to riverbed erosion downstream, disrupting habitats and aquatic ecosystems.
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Water Quality Issues: Stagnation in reservoirs can lead to decreased oxygen levels and increased temperatures, impacting aquatic life.
Example Case Study
- In the case of the Mississippi River, flood control measures like levees have been essential in protecting urban areas but also contribute to increased flooding risk downstream due to the lack of sediment replenishment.
Conclusion
Flood control measures can significantly impact river processes by altering flow dynamics, trapping sediments, and affecting water quality. While these measures aim to protect human activities, they can disrupt the natural balance of river ecosystems.
Step 2
The impact of coastal defence measures on coastal processes
Answer
Coastal defence measures, such as seawalls, groynes, and beach nourishment, are implemented to protect coastal areas from erosion and flooding.
Effects on Coastal Erosion
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Seawalls: While they protect the coastline, seawalls can lead to increased erosion at their base, resulting in scouring.
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Groynes: These structures trap sand on one side but can cause sand depletion on the other, leading to imbalances in sediment distribution along the coast.
Environmental Considerations
- The introduction of hard structures alters the natural coastal processes and may disrupt habitats for marine wildlife.
Conclusion
While coastal defence measures provide immediate protection against natural forces, they can exacerbate erosion issues and disrupt marine environments.
Step 3
The impact of human activities on mass movement processes
Answer
Human activities can significantly influence mass movement processes, such as landslides and soil erosion.
Triggers of Mass Movements
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Deforestation: Removing trees destabilizes slopes; roots anchor soil, and without them, landslides become more likely during heavy rainfall.
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Construction: Building on slopes can increase the risk of landslides by altering drainage patterns and adding weight to unstable slopes.
Mitigation Strategies
- Implementing reforestation or sustainable land management can help mitigate the risks associated with human activities.
Conclusion
Human activities have a direct impact on mass movement processes, leading to increased vulnerability to landslides and erosion, necessitating careful management of land use.