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Examine how changes in base level impact on geomorphic processes and landforms in a fluvial environment. - Leaving Cert Geography - Question C - 2016
Question C
Examine how changes in base level impact on geomorphic processes and landforms in a fluvial environment.
Worked Solution & Example Answer:Examine how changes in base level impact on geomorphic processes and landforms in a fluvial environment. - Leaving Cert Geography - Question C - 2016
Step 1
Impact on processes identified
Answer
Changes in base level significantly influence various geomorphic processes such as erosion, sediment deposition, and river channel dynamics. When base level rises, sediment has the potential to accumulate, leading to reduced erosion and the potential formation of deltas. On the other hand, a falling base level enhances erosion, often leading to increased down-cutting of the river channel. This can result in more pronounced features such as entrenched meanders and increased sediment transport.
Step 2
Impact on landform identified
Answer
As base level changes, notable landforms are affected. One major impact of a falling base level is the creation of terraces along riverbanks. These terraces form as the river cuts down deeper into the landscape, leaving behind remnants of former floodplains. Conversely, a rising base level can lead to the formation of sedimentary features such as alluvial fans and deltas, altering the landscape and affecting local ecosystems.
Step 3
Examination of impacts
Answer
Numerous specific examples illustrate these impacts on geomorphic processes and landforms:
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Erosion & sediment deposition: A rise in base level results in decreased energy for rivers, leading to sediment deposition which can form new landforms, such as deltas at river mouths.
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Down-cutting of rivers: A drop in base level increases the energy of a river, causing it to erode its bed, forming features such as canyons.
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Terracing: As rivers adjust to a new lower base level, they carve into the landscape, leaving terraces that indicate previous floodplain levels.
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Alluvial fans: In arid regions, a decline in base level can lead to the formation of alluvial fans as rivers spread out and deposit sediment where they lose velocity.
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Incised meanders: Reduced base level intensifies erosion on the outer banks of meanders, leading to more entrenched and sharp bends in the river.
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Floodplain formation: Changes in base level affect the flooding regime of a river, which in turn influences floodplain dynamics and health.
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Impacts on aquatic habitats: Fluctuations in base level can alter the habitats for aquatic and riparian species, impacting biodiversity.
Each of these impacts can be observed broadly, underscoring the critical role base level plays in shaping fluvial environments.