PHOTO PATTERN DATA ELEMENTS: LOESSIAL PLAIN
The Columbia Plateau- This region is a basalt-buried plain created by flows of molten
rock; young block mountains have formed ridges due to faulting. Major streams that cut
these ridges have formed deep canyons. Sand and silt picked up by westerly winds cover
the plains and ridges of the rolling plateau; wheat and fruit production form the basis of
agriculture. Irrigation is rapidly expanding the agricultural prospects of the region. (Semiarid)
Form
Ridges, parallel, contour terraced, irregular upland.
Drainage
Texture- drainage texture is of moderate density.
Pattern- the overall drainage pattern appears to be
dendritic, but the tertiary streams have a definite pinnate
pattern.
Gully Characteristics
Upper gullies are sub-V-shaped buy many approach
saucer-shaped.
Special Features
Contour plowing; pinnate pattern of tertiary valleys.
Color (Photo Gray Tones)
Contrasting light gray and medium gray tones.
Land Use
Agricultural crops, mostly wheat.
Vegetation
Scattered trees in valleys.
Source: Terrain analysis procedural guide for surface configuration, US Army engineer
topographic laboratories, p. 7-61