F.5 GCE AS-level - Unit 1.3c - Plenary

Which of the following landform features can be found in the upper course of rivers?

• Waterfalls

• Floodplain

• Plunge pools

• Levees

• Gorges

Which of the following conditions may lead to the formation of waterfalls?

• Two layers of rock with different levels of resistance

• • Water flowing over a plateau edge

• Water flowing over a coastal cliff

• Water flowing over a hanging valley

• Water flowing over a fault scarp

Reorder the following statements to explain the formation of waterfalls.

• Water flows over a step in the river’s profile and erodes vertically downwards through hydraulic action and abrasion.

• Undercutting occurs, creating an overhang of rock. Water spills over the overhang, eroding a deep plunge pool through cavitation.

• Undercutting continues until the overhang is unsupported and collapses.

• The collapsed material is eroded through attrition and transported downstream, and also increases the abrasion of the plunge pool.

• This process is repeated over and over, and the waterfall retreats upstream, leaving behind a steep-sided gorge.

Which of the following descriptions about the landform feature showing in the photos are correct?

• The pool formed at the bottom is called a 'plunge pool'.

• When waterfalls retreat, gorges will be formed.

• Vertical cliffs can be found.

• Large body of water can be found.

• Abrasion and hydraulic action can be found.

Put the correct label in the diagram.

a

b

c

d

g

Solution

Hydraulic action

More resistant rock

Abrasion

Less resistant rock

Traction

Suspension

Overhang

Attrition