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Definition

Landforms are the features of the earth that together make up the land surface. Landforms may be large such as a river terrace or floodplain; or small, such as a dune. Groups of landforms are called landscapes. Landforms are recognized by their shapes or “lay of the land,” by their positions relative to other landforms, and by the kinds of material under the landforms.

Landform Types

Three major landform types - upland, terrace, and floodplain - form a stair-step pattern in many landscapes. Rules for determining landform types are given below.



Upland landforms:
  1. Parent material is weathered bedrock, till, or loess.
  2. Soil is strongly developed.

  Upland hillslope — slope is 3% or more.


  Upland swell — slope is 2% or less and surface is convex.


  Upland depression or flat — slope is 2% or less and surface is concave or flat.
Outwash landforms (terraces, outwash plains, or lake plains):
  1. Either:
    1. Parent material is outwash or lacustrine deposit, any slope OR
    2. Parent material is eolian sand and slope is 2% or less.
  2. Soil is strongly developed.

  Outwash landform, hillslope — slope is 3% or more.


  Outwash landform, swell — slope is 2% or less and surface is convex.


  Outwash landform, depression or flat — slope is 2% or less and surface is concave or flat.
Dune:
  1. Parent material is eolian sand.
  2. Slope is 3% or more.

Floodplain:
  1. Parent material is alluvium.
  2. Located near a stream.
  3. Soil is weakly developed.

Filled depression:
Not in image
  1. Parent material is local overwash that is 20 inches or more thick.
  2. Most nearby landforms are uplands or outwash landforms (not floodplains).
  3. Soil is weakly developed.

Note:
The parent material, as judged previously, should be used to help determine the landform.

On nearly level landscapes, official judges, where possible, will place slope stakes across nearly level surfaces to show whether they are concave or convex. If the shape is not apparent, they will write convex surface or concave surface on the site card.

If the landform does not meet any of the guidelines above, official judges will write the name of the landform on the site card.


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