Landscapes Formed From Streams

Assignment: 11.1, pg. 261; 11.2, pg. 265.

Alluvium- ____________ deposited by streams

Stream drainage patterns

• Dentritic- Looks just like the trunk and branches from a ___________. Common where a stream erodes flat rock.
  
• Rectangular- a stream that bends at right angles! This stream forms over fractured or __________ rock.
  
• Radial- Looks just like ___________ spokes radiating out from a central point. Forms on ____________ and other conical hills.
  
• Centripetal- river channels that converge on a central ____________. Forms on a closed basin where there is no outlet
  
• Annular- a rare stream pattern of concentric circles. Forms on eroded _____________ of alternating layers of resistant and nonresistant layers
  
• Trellis- looks like a garden trellis- has a main stream with perpendicular streams intersecting it. Forms in the valleys between ___________ mountains
  
• _______________- a random stream pattern

Drainage Basins and Divides

Drainage Basin- the entire area that ____________ into a stream.

• Divides- the linear ___________ or highland that separates the drainage basins.

Steam Weathering, Deposition and Transportation

• Headward Erosion- streams that __________ uphill
  
• Gradient- the ___________ of the stream. Determined by dividing the change in height between two points of a stream by the distance between those points.
  
• Discharge- the __________ of stream flow.
  
• Load- the amount of ____________ the stream is carrying.
  
• Mass wastage- when sediment and debris move __________. Common on steep slopes of river valleys (or Saturday nights in NPZ).

*As a stream moves downhill, the gradient decreases, the discharge increases and the valleys widen.

Landscapes

• Floodplains- a flat raised boundary of a stream that accumulates sedimentary deposits during floods
• Stream terraces- old floodplains that are cut by _________ streams
• Levee- a deposit of ___________ parallel to the river flow during minor flooding events
• Yazoo tributary- a small stream that is ______ _____ from joining the main river by a levee.
• Delta- the triangular deposition of sediments at the _______ of a stream.
• Alluvial fan- the triangular deposition of sediments at the base of a mountain where the ____________ suddenly changes from high to low.

Stream Channel Types

• Braided stream- a low gradient stream that is formed by the ___________ of many streams that weave back and forth across each other
  
• Straight- a stream that flows without _____________.
  
• Meandering- the stream that curves back and forth.
  
• Point bar- the deposition of sediments on the __________ of the curve of a stream
  
• Cutbanks- the eroded __________ of the curve of a stream.
  
• Oxbow lake- an abandoned _____-shaped lake formed by the truncation of one of the curves of a meandering stream during a flood.
• Attitude- the type of rock and how it trends. (this influences stream drainage patterns)