Meanders & Ox Bow lakes

Question 1

Ox-Bow Lakes

Answer 1

Two bends of a river erode closer towards each other.
This creates a very narrow neck as they start to form a loop.
FLOOD
The river now chooses to bypass the loop and water in the old meander slows from deposition. and loss of energy.
This eventually cuts off the supply of water creating an ox-bow lake.
*the ox-bow lake will eventually dry up and the sedimentation will leave behind a scar in the landscape.

Question 1

Meander

Answer 1

1- An alternating sequence of fast flowing sections of water (riffles) alternate with deeper slower moving sections (pools)
2- These alternating sections cause the river to swing from the outside bank, creating a helicoidal flow.
3- As the helicoidal flow speeds through the riffles it speeds up and erodes the outside bank. This is where abrasion usually occurs.
4- The flow slows down in the deep pools and energy is lost. Material is deposited by the time the flow reaches the inside bank creating a slip off slope.
5- Overtime the continued erosion of the outerbank and deposition in the inner bend the river channels bends to form a meander.
6-This can cause the river to migrate across the floodplain and create more defined loops as two bends erode towards each other.