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Rivers and Geomorphology. CGF3M. Rivers. 1. Energy. 2. Stages of River Development. 3. Drainage Basins. 4. River Patterns. 5. Geomorphological Features. Energy. Features due to erosion or deposition depending on speed. Low energy/low speed = deposition High energy/high speed = erosion. - PowerPoint PPT Presentation
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Rivers and GeomorphologyCGF3M
Rivers
1. Energy
2. Stages of River Development
3. Drainage Basins
4. River Patterns
5. Geomorphological Features
Energy• Features due to erosion or deposition
depending on speed.• Low energy/low speed = deposition• High energy/high speed = erosion
Stages of River Development
A: Youthful/Upper StageB: Mature/Middle StageC: Old/Low Stage
Stages of River Development
A: Youthful Stage• Steep, fast, straight, vertical erosion
B: Mature Stage• Less steep, slower, meanders, horizontal
erosion
C: Old Age Stage• Flat, slow, meandering, depositional
Drainage Basins• Area in which all raindrops eventually
drain into the same river system, ocean, or lake (catchment, watershed)
The Amazon Drainage Basin
Drainage Basins• Tributaries: smaller rivers that drain into
larger rivers.• Interfluves: pieces of higher land between
tributaries.• Divide: higher ground between drainage basins.
Drainage Basin
Drainage Patterns• Main river = trunk• Tributaries = branches• Distributaries = roots
Drainage Patterns• 5 Drainage Patterns:
– Dendritic – Trellis – Radial– Deranged– Rectangular
Drainage Patterns
Dendric Drainage Pattern• Flow across level land, merging with other
rivers• Resemble branching tree
Trellis and Rectangular• Ground is made of folded bedrock, rivers
may follow a straighter course along the softer bedrock, with hard rock on either side.
• Often in mountainous areas.• Trellis: one main trunk• Rectangular: square pattern
Radial Pattern• Landforms influenced by volcanoes and
cone-shaped hills.• Streams radiate outward in all directions
from central zone
Deranged Pattern• No distinct pattern noted• Often lakes are found throughout• Glaciation has torn the landscape leaving this deranged pattern
Geomorphological Features• Levees: sediments deposited in the
stream channel that contain the water. (ridges).
Geomorphological Features• Meander: sinuous back and forth sweep of
a river in old age.• Meander scar: an oxbow lake that has
dried up leaving a dry hollow where the river channel had been.
Geomorphological Features• Oxbow lakes: an area of poor drainage
that occurs when a meander is cut off from the main river channel, forming a lake.
Geomorphological Features• Delta: depositional feature found at the
mouth of a river.• River’s water reaches mouth of river and
the sediment is carried settles.
Geomorphological Features• Estuary: the flooded mouth of a river
valley.