Mixed Alluvial Lands

Mapping Symbol: Ma

This mapping unit consists of a variety of alluvial soils in areas that are too small and too closely associated to map separately at the scale used in the Soil Survey. Slopes are generally 0 to 2%. The hazard of flooding is severe. 

Typical Profile: Variable, ranges from sand and gravelly sand to silty clay loam

Permeability: Very poor drained to highly permeable

Rooting Depth: Variable

Depth to Seasonal High Water Table: Generally at surface

Available Water Holding Capacity: Highly variable

Runoff Potential: Slow 

Erosion and Slippage Hazard: Slight 

Flooding Potential: Severe

Use and Management: Primary uses of these soils are for pasture and timber. Pasture forage yields are 2.0 tons/acre/year with good management. These soils may be very wet in the Spring, delaying their use. Douglas-fir, Western Red Cedar, Red Alder, and Bigleaf Maple are important tree species on all soil slope classes. There are moderate limitations on equipment use for site preparation and timber harvest because of their wetness and flooding potential. This soil has severe limitations on recreational and engineering uses because of its potential for flooding. 

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