M332Dk Central Montana Broad Valleys

Landscape Characteristics:

Broad intermontane valleys that formed in Tertiary sediments and Quaternary alluvial deposits derived from volcanic rocks, shale, and sandstone. Elevations range from 3750 to 6800 feet. Drainage density is low.

Climate:

Mean annual precipitation ranges from 10 to 25 inches, about 30 percent falling as snow. The soil temperature and moisture regimes are frigid and aridic ustic.

Potential Vegetation:

Foothills prairie/Grama-needlegrass-wheatgrass/Sagebrush steppe

Relationships of Dominant Map Unit Components:

Landform Geology Soil Taxa
Terraces/fans/foothills Alluvium Argiborolls/Haploborolls/Calciorthids/Haplargids
Floodplains Alluvium Haplaquolls/Fluvaquents

Disturbance and Land Use:

The primary natural disturbances are fire and flooding. Land use is predominantly livestock grazing, crop production, and urban/suburban development.