Features

• What results from vertical erosional flow in rivers?

  Formation of hills
• What happens when gullies are deep enough to tap into rainwater and groundwater flow?

  They form permanent river channels
• How does the long profile of a river change from source to mouth?

  The gradient decreases from source to mouth
• What type of erosion occurs near the source of a river?

  Vertical erosion
• What type of erosion occurs near the mouth of a river?

  Lateral erosion
• What happens to the gradient as a river approaches base level?

  The gradient decreases
• What attributes of a river increase downstream?

  Width, depth, hydraulic radius, velocity, and discharge
• What attributes of a river decrease downstream?

  Gradient, size, and gradient
• What are the characteristics of the upper, middle, and lower courses of a river?

  • Upper Course:
  • High velocity
  • Steep gradient
  • Narrow channels
  • V-shaped valleys
  • Rapids
  • Middle Course:
  • Increased channel size
  • Decreased gradient
  • Meanders and floodplains
  • Lower Course:
  • Gentle gradient
  • Wide channels
  • Sinuous meanders
  • Multiple floodplains
• What features are common in the upper course of a river?

  Interlocking spurs, waterfalls, and rapids
• How does the velocity of a river change from the upper course to the middle course?

  Velocity increases in the middle course
• What features develop in the middle course of a river?

  Meanders and floodplains
• What are ox-bow lakes?

  Remnants of former meanders disconnected from the river channel
• How do ox-bow lakes form?

  Through lateral erosion and meander migration
• What is the role of the thalweg in river formation?

  It directs maximum velocity and erosion in the river channel
• What is a floodplain?

  The flat land area on either side of a river channel
• How do floodplains form?

  Through lateral erosion as rivers migrate
• What are pools and riffles in a river?

  Pools are deeper areas, and riffles are shallower areas with coarser gravel
• How do pools and riffles form in a river?

  Through water flow around obstructions like boulders
• What is sinuosity in river channels?

  The degree to which a river channel deviates from a straight line
• What is the typical sinuosity value for a straight river?

  A low sinuosity value of 1.0
• What happens to the sinuosity of a river as meanders develop?

  The sinuosity of the channel increases
• How does helical flow contribute to meander formation?

  It erodes the outer bank and deposits material on the inner bank
• What is the economic value of waterfalls?

  They attract tourists and provide hydroelectric power
• What processes contribute to the formation of waterfalls?

  Hydraulic action, abrasion, and solution
• What happens to the overhanging rock at a waterfall over time?

  It enlarges and eventually collapses into the plunge pool
• How does the plunge pool at a waterfall deepen?

  Through abrasion and the impact of falling water
• What is the height of the falls on the Canada-USA border?

  51 m
• How does the retreat of a waterfall create a gorge?

  By eroding upstream as the waterfall retreats
• What is the length of the gorge created by the falls on the Canada-USA border?

  11 km
• What is the process of attrition in river erosion?

  It is the breaking down of eroded materials by collision
• What is the role of sediment in the erosion process at waterfalls?

  It scours the bed and banks, enhancing erosion
• How do oxbow lakes eventually become meander scars?

  Through sedimentation and plant invasion over time
• What is the significance of tributaries in the lower course of a river?

  They increase the width and depth of the river channel
• What happens to the material carried by a river in the lower course?

  It is carried in suspension and solution
• How do levees form along river channels?

  Through sediment deposition during floods
• What is the relationship between river discharge and erosion?

  Increased discharge leads to increased energy for erosion
• What is the impact of high discharge on river channels?

  It can lead to the formation of new, faster routes
• How does the river's energy change during flooding?

  The river's energy increases, allowing for more erosion
• What is the effect of vegetation on oxbow lakes over time?

  It leads to sediment accumulation and lake siltation