LOCATION CHILLIWACK              WA

Established Series
IRD CAB/SBC
08/2011

CHILLIWACK SERIES

The Chilliwack series consists of very deep, well drained soils formed in volcanic ash and glacial drift on debris aprons, valley walls, bedrock benches, and Pleistocene moraines. Slopes are 15 to 65 percent. The mean annual precipitation is about 1,800 millimeters. The mean annual temperature is about 6 degrees C.

TAXONOMIC CLASS: Medial over sandy or sandy-skeletal, amorphic over isotic Andic Haplocryods

TYPICAL PEDON: Chilliwack medial sandy loam, on a debris apron landform with a west facing slope of 10 percent at 915 meters elevation under coniferous forest vegetation. When described on August 28, 2005 the soil was dry throughout. (Colors are for moist soil unless otherwise noted.)

Oe--0 to 3 cm; moderately decomposed plant material; abrupt wavy boundary.

E--3 to 13 cm; brown (7.5YR 5/2) medial sandy loam, light gray (7.5YR 7/1) dry; moderate medium subangular blocky structure; slightly hard, very friable, nonsticky, nonplastic; few very fine, fine, medium, and coarse roots; 5 percent fine gravel; extremely acid (pH 4.4); abrupt irregular boundary.

Bs1--13 to 34 cm; strong brown (7.5YR 4/6) gravelly medial sandy loam, strong brown (7.5YR 5/8) dry; moderate medium subangular blocky structure parting to strong very fine subangular blocky structure; moderately hard, friable, nonsticky, nonplastic; many very fine and fine and common medium and coarse roots; 5 percent fine gravel, 5 percent medium and coarse gravel, and 5 percent cobbles; strongly acid (pH 5.5); clear irregular boundary.

Bs2--34 to 46 cm; strong brown (7.5YR 4/6) gravelly medial sandy loam, strong brown (7.5YR 5/6) dry; moderate medium subangular blocky structure parting to strong very fine subangular blocky structure; moderately hard, friable, nonsticky, nonplastic; common very fine and fine and few medium and coarse roots; 10 percent fine gravel, 10 percent medium and coarse gravel, 5 percent cobbles, and 2 percent stones; moderately acid (pH 5.6); clear irregular boundary.

2BC--46 to 70 cm; dark yellowish brown (10YR 4/6) extremely gravelly loamy sand, yellowish brown (10YR 5/6) dry; weak medium subangular blocky structure; moderately hard, friable, nonsticky, nonplastic; few very fine, fine, and medium roots; 15 percent fine gravel, 35 percent medium and coarse gravel, 10 percent cobbles, and 5 percent stones; moderately acid (pH 5.7); clear wavy boundary.

2C--70 to 150 cm; olive brown (2.5Y 4/4) extremely gravelly loamy sand, light olive brown (2.5Y 5/6) dry; single grain; loose, nonsticky, nonplastic; few very fine, fine, and medium roots; 20 percent fine gravel, 40 percent medium and coarse gravel, 15 percent cobbles, and 5 percent stones; moderately acid (pH 6.0).

TYPE LOCATION: North Cascades National Park, Skagit County, Washington; 184 meters north and 743 meters east of the southwest corner of Section 5, T35N, R14E Willamette Meridian; Forbidden Peak, Washington USGS quadrangle; 48 degrees, 32 minutes, 38 seconds north latitude and 121 degrees, 41 minutes, 54 seconds west longitude; NAD83; UTM 646507 meters E, 5378644 meters N, zone 10.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 4 to 8 degrees C. Cryic soil temperature regime.
Soil moisture control section: dry for less than 30 consecutive days from June to October. Udic soil moisture regime.
Thickness of volcanic ash mantle (medial textural modifier): 40 to 75 centimeters
The particle-size control section in this soil is contrasting. Most characteristics are listed by horizon.

E horizon:
Hue - 7.5YR or 10YR
Value - 4 to 6 moist, 5 to 7 dry
Chroma - 1 or 2 moist or dry
Fine earth texture - medial FSL or medial SL
Rock fragments - 5 to 30 percent total
5 to 30 percent gravel
0 to 10 percent cobbles
0 to 5 percent stones
Clay content - 3 to 8 percent
Volcanic glass - 35 to 80 percent
Reaction - extremely acid to very strongly acid
Thickness - 2 to 16 centimeters

Bhs horizons are sometimes present with thickness ranging from 1 to 4 centimeters, textures of medial SL or medial FSL, reaction of very strongly acid or strongly acid, hue of 7.5YR or 5YR, moist value of 2 to 4, and moist chroma of 2 or 4.

Bs horizons:
Hue - 7.5YR
Value - 3 to 5 moist, 5 to 6 dry
Chroma - 4 or 6 moist or dry
Fine earth texture - medial SL or medial COSL
Rock fragments - 10 to 30 percent total
10 to 30 percent gravel
0 to 10 percent cobbles
0 to 10 percent stones
Note: lower portions of Bs2 or Bs3 horizons may have rock fragment that range from 15 to 75 percent.
Clay content - 2 to 10 percent
Volcanic glass - 15 to 70 percent
Reaction - very strongly acid to moderately acid
Thickness - 30 to 70 centimeters

2BC horizons:
Hue -10YR or 2.5Y
Value - 3 to 5 moist, 5 to 6 dry
Chroma - 4 or 6 moist or dry
Fine earth texture - SL, COSL, LS, or LCOS
Rock fragments - 35 to 80 percent total
20 to 60 percent gravel
5 to 20 percent cobbles
0 to 10 percent stones
Clay content - 1 to 6 percent
Volcanic glass - 5 to 15 percent
Reaction - strongly acid to moderately acid
Thickness - 20 to 40 centimeters

2C horizon:
Hue -2.5Y or variegated
Value - 3 to 5 moist, 5 to 6 moist
Chroma - 3 to 6 moist or dry
Fine earth texture -LS, LCOS, or COS
Rock fragments - 50 to 85 percent total
30 to 75 percent gravel
10 to 20 percent cobbles
0 to 20 percent stones
Clay content - 0 to 4 percent
Volcanic glass - 0 to 10 percent
Reaction - moderately acid to slightly acid

COMPETING SERIES: There are no competing series in this family. The Benka, Chulitna, Kashwitna, Nancy, and Soldotna series have mixed mineralogy, silt loam textures, and mean annual soil temperature of less than 3 degrees C. The Shoestring series has mixed mineralogy and a 2Bs horizon with 30 to 45 percent pumice fragments.

GEOGRAPHIC SETTING: The Chilliwack soils are on debris aprons, valley walls, bedrock benches, and Pleistocene moraines at elevations 900 to 1,800 meters. Slopes are 5 to 55 percent. These soils formed in volcanic ash and glacial drift. The climate consists of cool, dry summers and cold, wet winters. Mean annual precipitation ranges from 1,800 to 3,000 millimeters, and mean annual air temperature ranges from 2 to 6 degrees C. Frost-free season is 30 to 60 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Maggib (T), Mox (T), Noca (T), and Spickard (T) soils. Maggib soils are moderately deep and form on bedrock benches. Mox soils have higher organic carbon accumulation in the Bs horizons and form on the most stable portions of bedrock benches and Pleistocene moraines. Noca soils lack strong spodic horizons and form on slightly less stable portions of all the same landforms. Spickard soils lack albic or spodic horizons and form on younger portions of debris aprons and valley walls.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained, high to very high saturated hydraulic conductivity.

USE AND VEGETATION: Used for watershed, recreation, woodland and wildlife habitat. Native vegetation is western hemlock, Pacific silver fir and minor western redcedar with an understory of queencup beadlily, twinflower, rattlesnake plantain, huckleberry, and Cascade azalea.

DISTRIBUTION AND EXTENT: Western slopes of the North Cascade Mountains, Washington. MLRA 3. Series is of small extent.

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

SERIES ESTABLISHED: North Cascades National Park Service Complex soil survey, 2011.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Particle-size control section: 25 to 100 centimeters
Ochric epipedon: 0 to 18 centimeters (Oe, E, and upper 5 centimeters of Bs1 horizon)
Albic horizon: 3 to 13 centimeters (E horizon)
Spodic horizons: 13 to 46 centimeters (Bs horizons)
Andic soil properties: 3 to 46 centimeters (E and Bs horizons)
Lithologic discontinuity: 46 centimeters

ADDITIONAL DATA: Laboratory data is available for this series. National Soil Survey Laboratory Pedon number 06N0802 (User Pedon ID 05WA057005).

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National Cooperative Soil Survey
U.S.A.