LOCATION CHIWAUKUM WAEstablished Series
TAXONOMIC CLASS: Medial over loamy-skeletal, amorphic over isotic Andic Haplocryods
TYPICAL PEDON: Chiwaukum bouldery medial fine sandy loam-forested on a 34 percent north-facing slope at an elevation of 3,100 feet. (Colors are for dry soils unless otherwise noted. All textures are apparent field textures.)
Oi--0 to 1 inch; decomposed forest litter.
E--1 to 3 inches; light gray (10YR 7/1) bouldery medial fine sandy loam, gray (10YR 5/1) moist; weak medium crumb structure; soft, very friable, nonsticky and nonplastic; many fine and very fine roots; common very fine tubular pores; 5 percent gravel, 5 percent cobbles, and 5 percent surface boulders, moderately acid (pH 6.0); abrupt smooth boundary. (1 to 3 inches thick)
Bs1--3 to 6 inches; brown (7.5YR 5/4) medial fine sandy loam, dark brown (7.5YR 3/4) moist; moderate medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; moderate fine, medium and coarse roots; common very fine tubular pores; 5 percent gravel, and 5 percent cobbles, slightly acid (pH 6.2); clear wavy boundary. (2 to 4 inches thick)
Bs2--6 to 18 inches; brown (7.5YR 5/4) gravelly medial sandy loam, dark brown (7.5YR 3/4) moist; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; moderate fine and medium roots; common very fine tubular pores; 15 percent gravel and 5 percent cobbles; slightly acid (pH 6.5); gradual wavy boundary. (10 to 15 inches thick)
BC--18 to 27 inches; yellowish brown (10YR 5/4) cobbly medial sandy loam, dark yellowish brown (10YR 3/4) moist; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; moderate fine and medium roots; few very fine tubular pores; 5 percent gravel, 10 percent cobbles and 2 percent stones; slightly acid (pH 6.5); clear wavy boundary. (7 to 15 inches thick)
2C--27 to 61 inches; light brownish gray (10YR 6/2) extremely stony coarse sandy loam, dark grayish brown (10YR 4/2) moist; massive; soft, very friable, nonsticky and nonplastic; few fine, medium and coarse roots; few fine tubular pores; 25 percent gravel, 15 percent cobbles and 20 percent stones; neutral (pH 6.8).
TYPE LOCATION: Chelan County, Washington; about 8 miles east of Stevens Pass, 900 feet east and 2,350 feet north of the southwest corner sec. 9, T. 26 N., R. 15 E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 41 to 45 F. These soils are dry for an estimated 45 to 60 consecutive days following summer solstice. Depth to the 2C horizon is 20 to 36 inches from the mineral soil surface. The upper part of the particle-size control section from 11 to 27 inches has an estimated moist bulk density of 0.85 to 1.10 g/cc, volcanic glass content of 30 to 60 percent, acid-oxalate extractable aluminum plus one-half of the acid-oxalate extractable iron of more than 2 percent, and 15-bar water retention of more than 12 percent for air dried samples. The lower part of the particle-size control section averages 35 to 75 percent coarse fragments.
The E horizon has value of 4 to 6 moist, 5 to 7 dry, and chroma of 1 or 2 dry and 1 to 3 moist.
The Bs horizon has value of 3 to 5 moist, 4 to 6 dry and chroma of 2 to 6 dry and moist. Texture is medial fine sandy loam or medial sandy loam and is gravelly, cobbly, stony or cindery. It is slightly acid to strongly acid.
The BC horizon has hue of 10YR or 7.5YR, value of 5 to 7 dry, 3 to 5 moist, and chroma of 3 or 4 dry and 3 to 6 moist. Texture is medial sandy loam or medial fine sandy loam and is cobbly or gravelly. It is moderately acid to slightly acid.
The 2C horizon has hue of 2.5YR or 10YR, value of 4 to 6 moist, 5 to 7 dry, and chroma of 1 to 4 moist and 2 to 6 dry. Texture of the fine- earth fraction is coarse sandy loam, or sandy loam. It is very gravelly, extremely gravelly, very cobbly, extremely cobbly, very stony, or extremely stony. It is moderately acid or slightly acid.
COMPETING SERIES: This is the Soda series. The Almac soils have a similar classification.
Soda soils are dry for 30 to 45 consecutive days following the summer solstice (udic moisture regime)
Almac soils - have a mean annual temperature of 39 to 41 degrees F., are dry for 60 to 75 consecutive days following the summer solstice; have glassy over isotic mineralogy
GEOGRAPHIC SETTING: Chiwaukum soils are on mountain side slopes and valley bottoms. Elevations are 2,500 to 5,500 feet. Slopes are 3 to 65 percent. These soils formed in volcanic ash and pumice overlying glacial till or local colluvium. They are in a climate with warm, dry summers and cool, moist winters. The mean annual precipitation is 40 to 75 inches. The mean January temperature is about 22 degrees F. and the mean July temperature is about 59 degrees F. The mean annual temperature is about 40 degrees F. The frost-free season is 55 to 110 days and the growing season (28 degrees F.) is 95 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Choralmont and Icicle soils. Choralmont soils are ashy-pumiceous and have a cambic horizon. Icicle soils are loamy-skeletal, and have a cambic horizon.
DRAINAGE AND PERMEABILITY: Well drained, slow to rapid runoff, moderate permeability.
USE AND VEGETATION: These soils are used for woodland, wildlife habitat, watershed and recreation. Vegetation is lodgepole pine, subalpine fir, Pacific silver fir, Englemann spruce, grand fir, and Douglas-fir, with an understory of huckleberry pachystima, Oregon-grape, pyrola, pinegrass, lupine and rose.
DISTRIBUTION AND EXTENT: Cascade Mountains of Chelan County; MLRA 3. Series is moderate 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 pedon are:
Albic horizon - from 1 to 3 inches
Spodic horizon - from 3 to 18 inches
Lithologic discontinuity - at 27 inches.
Particle-size control section - 10 to 40 inches