The Four Processes of River Erosion

The Four Processes of River Erosion

Hydraulic Action:

• Definition: Hydraulic action is the process by which flowing water exerts pressure on the riverbanks, causing erosion through the force of the water.
• How It Works:
  • Water enters cracks and crevices in rocks and riverbanks.
  • The pressure exerted by the moving water widens these gaps and dislodges particles.
  • Over time, this constant pressure weakens the rock, leading to erosion.

Abrasion:

• Definition: Abrasion is the process of erosion by which rocks and pebbles carried by the river wear away the riverbanks and bed.
• How It Works:
  • As the river flows, it carries sediment (rocks, pebbles, and sand) in its current.
  • These particles are repeatedly scraped against the riverbanks and the riverbed.
  • This continuous rubbing action wears down the surfaces and causes erosion.

Attrition:

• Definition: Attrition occurs when rocks and pebbles within the river collide and break into smaller, smoother particles as they are transported by the water.
• How It Works:
  • As rocks and pebbles are carried by the river, they collide with each other.
  • These collisions cause the rocks to chip and break into smaller fragments.
  • Over time, these fragments become smoother and rounder, contributing to erosion.

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The Four Processes of River Erosion

Solution:

• Definition: Solution is the process of erosion where certain types of rocks (e.g., limestone) are dissolved by the slightly acidic water of the river.
• How It Works:
  • Water contains dissolved carbon dioxide, making it weakly acidic.
  • This acidic water can react with and dissolve certain minerals in rocks, like calcium carbonate in limestone.
  • The minerals dissolve into the river water and are carried away.