River Landforms
Meanders, ox-bow lakes, waterfalls/gorges, flood plains and levees.
- Created by: Georgia_1212
- Created on: 18-03-16 16:37
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- River Landforms
- Meanders
- Formed by erosion and deposition.
- In the middle and lower course, rivers develop large bends called meanders.
- The current is faster on the outside bend because the channel is deeper.
- Therefore more erosion takes place on the outside bend which forms river cliffs.
- The current is slower on the inside bend because the channel is shallower.
- Therefore eroded material is deposited on the inside bend which forms slip-off slopes.
- The current is slower on the inside bend because the channel is shallower.
- Therefore more erosion takes place on the outside bend which forms river cliffs.
- Mississippi River and River Thames have meanders.
- Ox-Bow Lakes
- As meanders get larger over time, they can turn into an ox-bow lake.
- Erosion causes the outside bends to get closer until there's only a small bit of land left in between the bends called the neck.
- The river then breaks through this land, manly during a flood.
- The river now flows straight through- not going round the bend because it is the shortest way.
- Deposition eventually cuts off the meander, which forms an ox-bow lake.
- The river now flows straight through- not going round the bend because it is the shortest way.
- The river then breaks through this land, manly during a flood.
- Waterfalls and Gorges.
- Formed by erosion.
- Waterfalls form where a river flows over an area of hard rock followed by an area of soft rock.
- The soft rock is eroded more than the hard rock, creating a step in the river.
- As water flows over the step, it erodes more of the softer rock. A steep drop is eventually created which is called a waterfall.
- The hard rock is undercut by erosion. Then it becomes unsupported and collapses.
- The rocks that have collapsed are swirled round at the bottom of the waterfall, where they erode the soft rock by abrasion. This creates a deep plunge pool.
- Overtime, more undercutting causes more collapses. This makes the waterfall retreat up the channel, which leaves a steep sided gorge.
- The rocks that have collapsed are swirled round at the bottom of the waterfall, where they erode the soft rock by abrasion. This creates a deep plunge pool.
- The hard rock is undercut by erosion. Then it becomes unsupported and collapses.
- As water flows over the step, it erodes more of the softer rock. A steep drop is eventually created which is called a waterfall.
- The soft rock is eroded more than the hard rock, creating a step in the river.
- Upper course.
- High Force waterfall is a waterfall on the River Tees.
- Flood Plain.
- Formed by deposition.
- Lower course.
- The flood plain is the wide valley floor on both sides of the river that sometimes gets flooded.
- When a river floods onto the flood plain, the water slows down and deposits the eroded material that it's carrying, This makes the flood plain higher.
- Meanders move across the flood plain, making it wider.
- The deposition that happens on the slip-off slopes of meanders also builds up the flood plain.
- Meanders move across the flood plain, making it wider.
- When a river floods onto the flood plain, the water slows down and deposits the eroded material that it's carrying, This makes the flood plain higher.
- Levees
- Formed by deposition.
- Lower course.
- Levees are natural embankments along the edge of the channel.
- During a flood, eroded material is deposited over the whole flood plain.
- The heaviest material is deposited closest to river channel, because it gets dropped first when the river slows down.
- Over time the deposited material builds up creating levees along the edges of the channel.
- The heaviest material is deposited closest to river channel, because it gets dropped first when the river slows down.
- During a flood, eroded material is deposited over the whole flood plain.
- The Yellow River in China has levees.
- Meanders
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