LOCATION BONNEVILLE              WA

Established Series
Rev. EH/TA/RJE
06/2011

BONNEVILLE SERIES

The Bonneville series consists of very deep, somewhat excessively drained soils or terraces. These soils formed in alluvial sand and gravel derived dominantly from basalt and andesite. Slopes are 0 to 5 percent. Elevation is 50 to 400 feet. The average annual precipitation is about 70 inches. The mean annual temperature is about 48
degrees F.

TAXONOMIC CLASS: Sandy-skeletal, mixed, mesic Typic Humixerepts

TYPICAL PEDON: Bonneville stony sandy loam - forested. (Colors are for moist soil unless otherwise noted.)

A1--0 to 6 inches; dark brown (10YR 3/3) stony sandy loam, brown (10YR 5/3) dry; weak fine granular structure; soft, very friable, slightly sticky and nonplastic; many very fine and fine and common medium roots; many coarse irregular pores; 20 percent pebbles, 5 percent cobbles, and 5 percent stones; moderately acid (pH 5.9); clear wavy boundary. (5 to 7 inches thick)

A2--6 to 12 inches; dark brown (10YR 3/3) extremely gravelly coarse sandy loam, brown (10YR 5/3) dry; single grained; loose; many very fine and fine and few medium roots; many coarse irregular pores; 50 percent pebbles, 10 percent cobbles, and 5 percent stones; moderately acid (pH 5.8); clear wavy boundary. (5 to 7 inches thick)

C1--12 to 20 inches; brown (10YR 4/3) extremely gravelly coarse sand, brown (10YR 5/3) dry; single grained; loose; common fine and medium roots; many coarse irregular pores; 55 percent pebbles, 10 percent cobbles, and 5 percent stones; slightly acid (pH 6.2); clear wavy boundary. (6 to 10 inches thick)

C2--20 to 30 inches; dark yellowish brown (10YR 4/4) extremely gravelly coarse sand, yellowish brown (10YR 5/4) dry; single grained; loose; many very fine, fine and medium and few coarse roots; many coarse irregular pores; 50 percent pebbles, 10 percent cobbles, and 5 percent stones; slightly acid (pH 6.1); clear wavy boundary. (0 to 12 inches thick)

C3--30 to 60 inches; dark yellowish brown (10YR 4/4) extremely gravelly coarse sand, light yellowish brown (10YR 6/4) dry; single grained; loose; common very fine and few fine roots; common coarse irregular pores; 60 percent pebbles, 5 percent cobbles and 15 percent stones; slightly acid (pH 6.2).

TYPE LOCATION: Skamania County, Washington, about 1/2 mile west of North Bonneville; 2,140 feet north and 200 feet east of the southwest corner of sec. 20, T. 2 N., R. 7 E., W.M.

RANGE IN CHARACTERISTICS: Mean annual soil temperature is 47 degrees to 53 degrees F. The soil moisture control section is dry in all parts for 45 to 60 consecutive days within the four months that follow the summer solstice. The umbric epipedon is 10 to 14 inches thick. Rock fragments in the particle-size control section average 60 to 80 percent including 35 to 60 percent pebbles, 5 to 10 percent cobbles, and 5 to 15 percent stones. The soil has 3 to 5 percent stones on the surface.

The A horizon has value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry.

The C horizon has value of 4 or 5 moist and 5 or 6 dry, It is loamy sand or sand, and is extremely cobbly or extremely gravelly. This horizon is moderately acid or slightly acid.

COMPETING SERIES: These are the Carstairs and Spanaway soils in other families. These soils have a strong influence of volcanic ash in the umbric epipedon including a bulk density of less than 0.95 in the upper 7 to 14 inches of the profile.

GEOGRAPHIC SETTING: Bonneville soils are on terraces at elevations of 50 to 400 feet and have slopes of 0 to 5 percent. These soils formed in alluvial sand and gravel derived dominantly from basalt and andesite. The climate is characterized by warm, dry summers and cool, wet winters. The average annual precipitation is 65 to 75 inches. Average January temperature is 30 degrees F; average July temperature 66 degrees F; and the mean annual temperature is 47 degrees to 51 degrees F. Frost-free season is 185 to 230 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the McBee, Newberg, Skamania, Steever, and Washougal soils. McBee soils are fine-silty. Newberg and Skamania soils are coarse-loamy. Steever soils are loamy- skeletal and have a udic moisture regime. Washougal soils are medial- skeletal.

DRAINAGE AND PERMEABILITY: Somewhat excessively drained; slow runoff; moderately rapid permeability in the A horizon and very rapid below.

USE AND VEGETATION: Used for pasture, homesites, wildlife habitat, recreation, and timber production. Overstory vegetation typically is Douglas-fir, red alder bigleaf maple, and some Oregon white oak, and black cottonwood. Understory and ground vegetation is vine maple, trailing blackberry, black cottonwood, western hazel, common snowberry, poison oak, and Oregon white oak.

DISTRIBUTION AND EXTENT: Southwestern Washington. Series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Skamania County, Washington, 1947.

REMARKS: Diagnostic horizons and features recognized in this pedon are an umbric epipedon from the surface to 12 inches and a particle-size control section from 10 to 40 inches that averages 71 percent rock fragments.

Classification only changed 7/98 based on 1998 Keys to Soil Taxonomy.

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National Cooperative Soil Survey
U.S.A.