Meander formation

• What is the term for the highest velocity of water in a river?

  Thalweg
• Where does the thalweg typically occur in a river?

  In the middle of the channel just below the surface
• What happens to the thalweg when changes occur to a river's profile?

  The thalweg may change position
• What occurs as water moves into the bend of a river?

  The thalweg shifts to the outside of the bend
• What is the effect of the thalweg shifting to the outside of the bend?

  It causes erosion of the bank
• What is hydraulic action in the context of river erosion?

  It is the force of moving water that erodes the bank
• What is abrasion in river processes?

  It is the wearing away of the riverbank by sediment and rocks
• What is helicoidal flow in a river?

  It is a corkscrew-like motion of water
• What effect does helicoidal flow have on the river cliff?

  It erodes the river cliff and makes the river deeper
• What is the deeper stream area created by erosion called?

  Pool
• How do the thalweg and helicoidal flow affect the velocity of water on the inside of a bend?

  They cause lower velocity of water
• What is the result of lower water velocity on the inside of a bend?

  It causes the deposition of fine silts and sands
• What happens to the eroded material from the pool?

  It tends to settle in the riffle
• What is formed as a result of deposition on the inside of a river bend?

  River beach
• What are the main processes involved in river meandering?

  • Thalweg shifts to the outside of bends
  • Erosion occurs due to hydraulic action and abrasion
  • Helicoidal flow erodes river cliffs and creates pools
  • Lower velocity on the inside of bends leads to deposition
  • Formation of river beaches and riffles
• What are the key features of a river meander?

  • Thalweg: highest velocity in the middle
  • Erosion on the outside bend
  • Deposition on the inside bend
  • Formation of pools and beaches
  • Riffles connecting meanders