River Landscapes

How do v-shaped valleys form?

1. Vertical erosion occurs as the gradient is steep so the river erodes downwards

2. Weathering occurs, causing the edges to be exposed

3. Mass movement occurs creating a v-shaped valley

How do interlocking spurs form?

in the upper course where the river has low energy

so erodes the softer rock and moves around the harder rock

How do waterfalls and gorges form?

1. Hard rock overlays soft rock along the river channel

2. The softer less resistant rock erodes more quickly forming a plunge pool

3. The plunge pool continues to erode due to hydraulic action and abrasion- an overhang of harder rock forms above

4. The overhang collapses due to gravity and contributes to the abrasion of softer rock below

5. Overtime, the waterfall retreats upstream forming a steep valley called a gorge

How do meanders and ox-bow lakes form?

1. The fastest water erodes the outside of the meander and deposition occurs on the inside

2. the meander gets tighter forming a swan’s neck meander

3. at high discharge, the river has enough energy to erode a new channel across the neck of the meander

4. the river now uses this new channel so deposition closes the sides of the meander and an ox-bow lake is formed

How do floodplains and levees form?

1. During high discharge, the river flood in the lower course

2. Heaviest sediment is deposited first forming natural levees

3. As the floodwater loses energy, smaller sediment is deposited further from the channel

4. A floodplain forms over many years as layers of sediment are deposited