River landscapes

• What is a drainage basin?

  An area of land drained by a river
• What is the boundary of a drainage basin called?

  Watershed
• What are the three sections of a river?

  • Upper course
  • Middle course
  • Lower course
• How does the shape of a river change across its sections?

  It varies from narrow and v-shaped to wide and deep
• What characterizes the upper course of a river?

  Tributaries are narrow and v-shaped
• What happens to the volume of water in the upper course?

  It has a low volume of water
• What is the shape of the river channel in the middle course?

  Rounder and deeper than the upper course
• What causes more erosion in the middle course?

  Higher volume of water and energy
• What is the predominant process in the lower course of a river?

  Deposition
• What are levees in relation to a river?

  Ridges along the river banks
• How does the velocity of water change from the upper to lower course?

  It increases due to less friction
• What are the two types of erosion that occur in rivers?

  Vertical and lateral erosion
• What are the four types of river erosion?

  • Abrasion
  • Attrition
  • Hydraulic Action
  • Corrosion (Solution)

  
• What is abrasion in river erosion?

  Rocks scrape against the river channel
• What happens during attrition?

  Rocks hit each other and become smaller
• What is hydraulic action?

  Water pressure widens cracks in rocks
• How does corrosion occur in rivers?

  Water dissolves chemical compounds in rocks
• What is the load in a river?

  • Material transported by the river
  • Includes rocks, plants, and chemicals
• What are the four types of river transportation?

  • Solution
  • Suspension
  • Saltation
  • Traction

  
• What is solution in river transportation?

  Chemicals dissolved in river water
• What is suspension in river transportation?

  Particles float within the water
• What is saltation in river transportation?

  Pebbles bounce along the river channel
• What is traction in river transportation?

  Large rocks rolled along the riverbed
• What happens during deposition in a river?

  Load is dropped when water slows
• Where does the most deposition occur in a river?

  In the lower course of the river
• What are the typical landforms in the upper course of a river?

  • Waterfalls
  • Interlocking Spurs
  • V-Shaped Valley
• What are the typical landforms in the middle course of a river?

  • Gorges
  • Meanders
• What are the typical landforms in the lower course of a river?

  • Floodplains
  • Ox-Bow Lake
  • River Estuary
• How do interlocking spurs form?

  Water curls around resistant rocks
• What causes waterfalls to form?

  Rivers flow over hard and soft rock
• What are the steps in waterfall formation?

  1. Soft rock erodes faster than hard rock
  2. Soft rock undercuts hard rock, creating an overhang
  3. Overhang collapses, deepening the plunge pool
  4. Waterfall retreats upstream over time

  
• What are gorges formed from?

  Retreating waterfalls carving steep valleys

  
• How do meanders form in a river?

  • Water travels faster on the outside bend
  • Lateral erosion occurs, creating a river cliff
  • Slower water on the inside deposits sediment
• What is the thalweg in a river?

  The path of the fastest water flow
• How is an ox-bow lake formed?

  From the separation of a meander due to erosion
• What are the common depositional landforms in the lower course?

  • Floodplains
  • Levees
• How do floodplains form?

  From sediment deposition during river floods
• What are levees in relation to river flooding?

  Higher banks that contain floodwater
• What happens when a river floods over levees?

  Floodwater spreads across the floodplain

  
• What is the finer sediment deposited called?

  Alluvium