Fluvial processes
River profiles: transverse and longitudinal profiles and
their relationship to the different stages of a river
River profiles
The profile of the river is determined by the amount of energy available in the drainage
basin. Rivers use this energy to perform work, erode the landscape, transport material and
when the river looses energy it will deposit its load. The energy in a river is determined by
the gradient and volume of water. The steeper the gradient the faster river will flow. The
more water (volume) in a river the faster it will flow. The opposite occurs when the gradient
or the volume decreases, the river will flow at a slower rate
gradient: the steepness of the slope
mouth: where the river flows into the
sea
source: where the river starts/
originates
note: transverse profile = cross profile
, Longitudinal profile Transverse profile
the shape of the river from its source to the shape of the river channel from bank
the mouth to bank
this gives a good indication of a river's shape of the profile changes along the
gradient course of the river due to the rivers ability
ideal profile is concave or graded in shape to erode and transport its load
Upper course
the gradient is steepest near the source where the gradient is steep, for example
near the source of the river, vertical
erosion takes place
a narrow transverse profile develops
Middle course
the gradient is less steep in this stage of the gradient is less steep
the river lateral erosion takes place
results in a wider transverse profile
Lower course
gentlest gradient along this stage of the the gradient is the most gentle
river shape of the transverse profile is wide
open
1. Narrow V-shaped valley
2. More open valley
3. Wide open valley
, Identification and description of fluvial landforms: meanders,
oxbow lakes, braided streams, floodplains, natural levee,
waterfall, rapids and delta
when the river has energy to erode due to an increase in gradient or volume, landforms
such as waterfalls and rapids are created
when the velocity and energy decreases, depositional features will occur
Upper course: Middle course: Lower course:
steep gradient gradient is less steep gentle gradient
little water volume of water increased large volume of water
vertical erosion occurs because of tributaries adding transverse profile (very wide
transverse profile (V water to the main stream channel shape)
shape) transverse profile (wider transportation
turbulent flow channel shape) more deposition than erosion
transport mainly lateral and vertical erosion wide flood plain
bedload, little solution takes place large flood plain, large
or suspension more suspension load meanders, ox-bow lakes,
mainly transportation water not as clear levees, braiding and deltas
and erosion deposition of pebbles and
waterfalls, rapids, gravel, sand and clay
potholes, gorges, large mainly transportation erosion
boulders, no flood deltas, rapids, lakes, small
plain, interlocking meanders and small flood
spurs plain, asymmetrical channel red = landform features
River profiles: transverse and longitudinal profiles and
their relationship to the different stages of a river
River profiles
The profile of the river is determined by the amount of energy available in the drainage
basin. Rivers use this energy to perform work, erode the landscape, transport material and
when the river looses energy it will deposit its load. The energy in a river is determined by
the gradient and volume of water. The steeper the gradient the faster river will flow. The
more water (volume) in a river the faster it will flow. The opposite occurs when the gradient
or the volume decreases, the river will flow at a slower rate
gradient: the steepness of the slope
mouth: where the river flows into the
sea
source: where the river starts/
originates
note: transverse profile = cross profile
, Longitudinal profile Transverse profile
the shape of the river from its source to the shape of the river channel from bank
the mouth to bank
this gives a good indication of a river's shape of the profile changes along the
gradient course of the river due to the rivers ability
ideal profile is concave or graded in shape to erode and transport its load
Upper course
the gradient is steepest near the source where the gradient is steep, for example
near the source of the river, vertical
erosion takes place
a narrow transverse profile develops
Middle course
the gradient is less steep in this stage of the gradient is less steep
the river lateral erosion takes place
results in a wider transverse profile
Lower course
gentlest gradient along this stage of the the gradient is the most gentle
river shape of the transverse profile is wide
open
1. Narrow V-shaped valley
2. More open valley
3. Wide open valley
, Identification and description of fluvial landforms: meanders,
oxbow lakes, braided streams, floodplains, natural levee,
waterfall, rapids and delta
when the river has energy to erode due to an increase in gradient or volume, landforms
such as waterfalls and rapids are created
when the velocity and energy decreases, depositional features will occur
Upper course: Middle course: Lower course:
steep gradient gradient is less steep gentle gradient
little water volume of water increased large volume of water
vertical erosion occurs because of tributaries adding transverse profile (very wide
transverse profile (V water to the main stream channel shape)
shape) transverse profile (wider transportation
turbulent flow channel shape) more deposition than erosion
transport mainly lateral and vertical erosion wide flood plain
bedload, little solution takes place large flood plain, large
or suspension more suspension load meanders, ox-bow lakes,
mainly transportation water not as clear levees, braiding and deltas
and erosion deposition of pebbles and
waterfalls, rapids, gravel, sand and clay
potholes, gorges, large mainly transportation erosion
boulders, no flood deltas, rapids, lakes, small
plain, interlocking meanders and small flood
spurs plain, asymmetrical channel red = landform features
