LOCATION BIGCREEK WAEstablished Series
TAXONOMIC CLASS: Ashy over pumiceous or cindery, aniso, glassy, frigid Typic Vitrixerands
TYPICAL PEDON: Bigcreek paragravelly ashy sandy loam, woodland. (Colors ar for dry soil unless otherwise noted.)
Oi--0 to 1/2 inch; slightly undecomposed forest litter of needles, leaves, twigs and cones.
E--1/2 to 1 inch; light gray (10YR 7/1) paragravelly ashy loamy sand, dark grayish brown (10YR 4/2) moist; single grain; loose, nonsticky and nonplastic; few fine roots; 15 percent pumice; slightly acid (pH 6.4); broken smooth boundary. (0 to 1 inch thick)
Bw1--1 to 6 inches; pale brown (10YR 6/3) paragravelly ashy sandy loam, dark brown (7.5YR 3/4) moist; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and fine and common medium roots; many very fine and fine irregular and tubular pores; 15 percent pumice; neutral (pH 6.8); clear smooth boundary.
Bw2--6 to 17 inches; light yellowish brown (10YR 6/4) paragravelly ashy sandy loam, strong brown (7.5YR 4/6) moist; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and fine and common medium and coarse roots; many very fine and fine irregular and tubular pores; 20 percent pumice; neutral (pH 6.6); clear wavy boundary. (Combined thickness of the Bw horizons is 12 to 20 inches)
2BC--17 to 31 inches; very pale brown (10YR 8/2) and yellow (10YR 7/6) paragravelly ashy, light gray (10YR 7/2) and brownish yellow (10YR 6/6) moist; single grain; loose; nonsticky and nonplastic; few fine roots; 95 to 100 percent pumice; neutral (pH 7.0); abrupt smooth boundary. (12 to 16 inches thick)
3C1--31 to 34 inches; very pale brown (10YR 8/2), yellow (10YR 7/6) and very dark gray (10YR 3/1) ashy coarse sand (volcanic ash), light gray (10YR 7/2) and brownish yellow (10YR 6/6) moist; single grain; loose; nonsticky and nonplastic; few fine roots; 10 percent pumice; neutral (pH 7.0) abrupt smooth boundary. (2 to 4 inches thick)
4C2--34 to 39 inches; light yellowish brown (10YR 6/4) gravelly sandy loam, dark yellowish brown (10YR 4/4) moist; massive; soft, very friable, nonsticky and nonplastic; common fine and few medium and coarse roots; common fine tubular and irregular pores; 20 percent gravel, 5 percent cobbles and 5 percent pumice; slightly acid (pH 6.4); clear wavy boundary. (4 to 6 inches thick)
5C3--39 to 61 inches; multicolored extremely gravelly sand; single grain; loose; nonsticky and nonplastic; 60 percent gravel and 10 percent cobbles; slightly acid (pH 6.4).
TYPE LOCATION: Chelan County, Washington; about 1.5 miles east of Fish Lake; 1,900 feet west and 2,100 feet south of northeast corner section 13, T. 27N., R. 17E., W.M.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is about 45 degrees F. These soils are usually moist but are dry in the moisture control section for 60 to 75 consecutive days following the summer solstice. The upper 1 to 17 part of the particle-size control section has an estimate moist bulk density 0.65 to 0.85 g/cc, volcanic glass content of 30 to 60 percent, acid-oxalate extractable aluminum plus one-half of the acid-oxalate extractable iron of 1.0 to 2.0 percent and 15-bar water retention of less than 12.0 percent for air dried samples. The lower part of the particle-size control section has 85 to 100 percent pumice. Depth to the 5C3 horizon is 30 to 40 inches.
The E horizon, where present, has value of 6 through 8 dry, 3 through 5 moist, and chroma of 1 or 2 dry or moist. It is paragravelly ashy loamy sand or paragravelly ashy sandy loam. Soil reaction is slightly acid or neutral.
The Bw horizons have hue of 10YR or 7.5YR, value of 5, 6 or 7 dry, 3 or 4 moist, and chroma of 2 through 6 dry or moist. Texture is paragravelly ashy sandy loam or paragravelly ashy fine sandy loam. Soil reaction is slightly acid or neutral.
The 2BC horizon has value of 6 through 8 dry or moist and chroma of 2 through 6 dry or moist.
The 3C1 horizon has value of 3 through 8 dry, 2 through 7 moist, and chroma of 1 through 6 dry or moist. Texture is ashy sand, ashy coarse sand or ashy coarse sand. Soil reaction is slightly acid or neutral.
The 4C2 horizon has value of 5, 6 or 7 dry, 4 or 5 moist, and chroma of 3 or 4 dry or moist. Texture is gravelly sandy loam or gravelly fine sandy loam. Soil reaction is slightly acid or neutral.
The 5C3 horizon is extremely gravelly or extremely cobbly sand. Soil reaction is slightly acid or neutral.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Bigcreek soils are on low terraces adjoining rivers and streams at elevations of 1,800 to 2,500 feet. Slopes are 0 to 8 percent. These soils formed in volcanic ash, pumice and a small amount of loess over glacial outwash sand, gravel and cobbles. Bigcreek soils are in a climate with warm, dry summers and cold moist winters. The average annual air temperature is about 43 degrees F. with an average January temperature of about 23 degrees F. and an average July temperature of about 66 degrees F. The average annual precipitation ranges from 30 to 45 inches, the frost-free season is 75 to 110 days and the growing season at 28 degrees F. is 125 to 160 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Chiwawa, Choralmont, Mippon and Nevine soils. Chiwawa soils are on terraces and are dominated by volcanic ash throughout the 10 to 40 inch control section and have sandy-skeletal outwash below 40 inches. Choralmont soils are on mountainsides and are dominated by volcanic ash and pumice in the 10 to 40 inch control section. Mippon soils are on terraces and have A horizons 10 inches thick. Nevine soils are on moraines and mountains and lack pumice in the control section and are over loam, sandy loam or fine sandy loam.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderate permeability to 16 inches and rapid and very rapid below this depth.
USE AND VEGETATION: Timber production, recreation, watershed, wildlife habitat and homesites. Overstory vegetation includes Douglas-fir, grand fir, ponderosa pine, lodgepole pine and Western white pine. Understory vegetation is pinegrass, pachystima, silky lupine, longtube twinflower and western rattlesnake plantain.
DISTRIBUTION AND EXTENT: Central Chelan County, Washington. The series is small in extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Chelan County, Washington, 1995.
REMARKS: Diagnostic horizons and features recognized in this soil are an intermittent albic horizon at the mineral surface and a cambic horizon from below the intermittent albic horizon to 17 inches. The particle-size control section from 0.5 to 40.5 inches is ashy (1/2 to 17 inches), pumiceous (17 to 31 inches), the ashy horizon from 31 to 34 inches is too thin for contrasting, thus it is included with the 17 to 31 inch layer, the loamy part from 34 to 39 inches and sandy-skeletal from 39 to 40.5 inches. The PSCS is considered ashy over pumiceous or cindery and pumiceous or ashy-pumiceous over loamy.