erosional and depositional landforms in the river: formation

Created by: njj04
Created on: 10-04-21 19:26

how does a braided channel form?

formed due to the presence of bars and islands in the channel. bars and islands are formed when a steep channel gradient, variable discharges, easily erodible channel and high load are present, because they lead to more erosion and deposition

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how do pools and riffles form?

formed due to turbulence. pools are formed in deep areas due to erosion as energy levels are higher in deep areas. riffles are formed in shallow areas due to high velocities and eddies (circular currents of flow) causing deposition of coarse material

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how does a meander form?

formed when there is helicoidal flow, as it creates pools and riffles as well as a swaying thalweg which makes flow very unstable and turbulent, causing the channel to bend. also the corkscrew motion of helicoidal flow causes erosion on the outer bend and

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how does an oxbow lake form?

lateral erosion of the outer bend caused by helicoidal flow, and deposition on the inner bend, causes the neck of the meander to become very narrow. then during an event of high discharge eg flood, the water cuts through the neck, leading to a straighter

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how do waterfalls and gorges form?

caused by an undercutting of rock, leading to water spilling over a sudden change in gradient. rock is undercut when the soft rock beneath the hard rock is eroded faster due to abrasion/hydraulic action, leading the hard rock to overhang for water to flow

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how does a floodplain form?

land adjacent to the river channel over which flood water moves across. caused by erosion which removes any interlocking spurs, creating a wide and flat area. also deposition of material which increases the height of the floodplain

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how does a levee form?

formed when a river bursts its banks repeatedly eg during floods. causes erosion, which causes material to be deposited across a floodplain. during floods rivers lose energy, so coarser material is deposited at the banks, leading to levees forming as the

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how does a delta form?

formed when the river meats a body of water with a lower velocity eg sea. this leads to a reduction in the load capacity of a river, leading to deposition at the mouth of a river. flocculation occurs, where clay particles clump together due to the salt in

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Other cards in this set

Card 2

Front

how do pools and riffles form?

Back

Card 3

Front

how does a meander form?

Back

Card 4

Front

how does an oxbow lake form?

Back

Card 5

Front

how do waterfalls and gorges form?

Back

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erosional and depositional landforms in the river: formation