River Deposition

There are many types of River Deposition such as:

  1. Floodplain
  2. Meanders
  3. Delta
  4. Ox-Bow Lake

Floodplain

—A floodplain is a low-lying plain on both sides of a river that has repeatedly overflowed its banks and flooded the surrounding areas.

—When the floods subside, alluvium is deposited on the floodplain.

—The larger materials, being heavier, are deposited at the river banks while the finer materials are carried and deposited further away from the river.
—The larger materials at the river banks build up into embankment called levees.

Delta

—A delta is a flat piece of land built-up from layers of sediments deposited by a river where it enters a lake or calm sea.

—The river may have to branch into smaller distributaries to carry the water to the sea.

Meanders

—Meanders are loop-like bends in a river. The water flows round the meander in a spiral manner.

—This causes erosion to take place on the outer bank and deposition on the inner bank.

—Gradually, a steep river cliff is formed on the outer bank, making it concave in shape.

—On the inner bank, deposition of alluvial materials produces a gentle slip-off slope and the bank takes on a convex shape.

Ox-Bow Lake

—An oxbow lake is a crescent -shaped lake formed on a river when a meander has been cut through and abandoned.

—When a river meanders in very big loops, the outer bank is so rapidly eroded that the river cuts through the narrow neck of the meander.

—The river then flows straight through the channel. When deposition seals off the cut-off from the river channel, an oxbow lake is formed. It may silt up and eventually dry up.

1) The river is starting to meander. Erosion is greater on the outside of the bend, deposition more on the inside.

2) Large meanders have formed

3) The river cuts through the meander, leaving a straighter section and an ox-bow lake.

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