TA5. Alaska Alpine Swales

For testing in LRRs W, X, and Y.

On concave landforms, the presence of a surface mineral layer 10 cm (4 inches) or more thick having hue of 10YR or yellower, value of 2.5 or less, and chroma of 2 or less. The dark surface layer is at least twice as thick as the mineral surface layer of soils in the adjacent convex micro-positions.

User Notes: Soils with this indicator occur in concave areas where moisture accumulates. In these areas the source of the hydrology is meltwater from adjacent snowpacks that persist well into the growing season. The landscape generally is a complex microtopography of concave depressions and adjacent convex microhighs. Soils should be examined in both landscape positions and compared. If both positions have a mineral surface layer of the same color, but the dark surface layer is at least twice as thick in the concave position, the soil in the concave position is considered hydric. Make sure that there is reasonable evidence of the hydrology source, including either direct observation of the melting snowpack or aerial imagery that shows snowpack at that location earlier in the growing season.