Waterfalls, meanders, oxbow lakes and deltas

Question 1

How is waterfall formed? (Give 5 points)

Answer 1

Starts at a vertical band of water and it ends in the plunge pool at the bottom
Water in plungepool splash back and creates hydraulic action, eroding away the soft rock
The hard rock becomes an overhang, which will eventually fall into the plunge pool
The fallen overhang deepen the plunge pool by abrasion, and chips bits off by attrition
These processes repeat and the waterfall retreats back to its source, creating a steep ‘V’ shaped valley called a gorge

Question 2

How is a meander formed? (Give 3 points)

Answer 2

A meander starts as a slight bend
A river erodes on the outside bend and deposits on the inside bend
The erosion and deposition turns the bend into a meander

Question 3

How is an oxbow lake formed? (Give 3 points)

Answer 3

A meander bends more and more until it becomes a tight loop
When the river energy was high, it would cut straight across the loop, and travel back to it’s original path (meander cutoff)
The river keeps to its channel, and the loop is cut off and becomes an oxbow lake

Question 4

What might an oxbow lake turn into?

Answer 4

It might dry up and grow plant inside it

Question 5

How is a delta formed?

Answer 5

A delta is formed when the river deposits as its energy is low, and the material that it has dropped builds up and forms a new land, making a river a delta