Landscapes Formed From Streams

Assignment: Activity 2, A-C, pg. 247-249; Activity 4, pg. 253.

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)