Fluvial Processes Flashcards

All 12 cards in this deck

What is hydraulic action?

The force of moving water (and air compressed into cracks) breaking material away from the bed and banks.

What is abrasion in a river?

Sediment carried by the river scrapes against the bed and banks, wearing them away.

What is attrition?

Stones carried by the river collide with each other and break down, becoming smaller and rounder.

What is solution (corrosion) as a river erosion process?

Slightly acidic river water dissolves soluble rocks such as limestone and chalk.

What is the difference between vertical and lateral erosion?

Vertical erosion cuts downwards, deepening the channel and valley; lateral erosion cuts sideways, widening them.

What is traction as a transport process?

Large, heavy pebbles are rolled along the river bed.

What is saltation as a transport process?

Pebbles are bounced along the river bed.

What is suspension as a transport process?

Lighter sediment is carried (suspended) within the water.

What is solution as a transport process?

Material is carried as dissolved minerals within the water.

Why do rivers deposit sediment?

Because the river loses energy (velocity) and can no longer transport its load, e.g. in shallow water, on the inside of a bend, or at the mouth.

Give one reason the median size of sediment decreases downstream from the source.

Attrition between particles breaks the load down into smaller pieces.

True or false? Solution is both a process of erosion and a process of transport in a river.

True. Solution erodes soluble rock such as limestone, and also carries dissolved minerals within the water.