LOCATION WACA CA NV

Established Series
Rev. GLA/GMK/ET
01/2023

WACA SERIES

The Waca series consists of moderately deep, well-drained soils formed in material weathered from andesitic tuff. Waca soils are on mountains and have slopes of 5 to 75 percent. The mean annual precipitation is 127 centimeters and the mean annual temperature is about 5 degrees C.

TAXONOMIC CLASS: Medial-skeletal, amorphic, frigid Humic Vitrixerands

TYPICAL PEDON: Waca very gravelly medial coarse sandy loam - on a northwest facing concave slope of 35 percent under a cover of mixed conifers at 2073 meters elevation. (Colors are for dry soil unless otherwise stated).

Oi--0 to 5 cm; slightly decomposed plant material. (3 to 8 cm thick)

A1--5 to 28 cm; brown (10YR 5/3) very gravelly medial coarse sandy loam, very dark grayish brown (10YR 3/2) moist; massive; soft, very friable, nonsticky and nonplastic; few fine roots; 30 percent gravel, 14 percent cobbles; slightly acid (pH 6.2); abrupt smooth boundary. (8 to 23 cm thick)

A2--28 to 41 cm; brown (10YR 5/3) very gravelly medial coarse sandy loam, dark brown (10YR 3/3) moist; massive, soft, very friable, nonsticky and nonplastic; common very fine and fine, many medium roots; many very fine and fine interstitial pores; 35 percent gravel, 3 percent cobbles; moderately acid (pH 6.0); diffuse wavy boundary. (10 to 15 cm thick)

A3--41 to 58 cm; brown (10YR 5/3) very gravelly medial coarse sandy loam, dark brown (10YR 3/3) moist; weak medium granular structure; soft, very friable, nonsticky and nonplastic; many very fine, fine, medium and coarse roots; many very fine and fine interstitial pores; 35 percent gravel, 2 percent cobbles; moderately acid (pH 5.8); diffuse wavy boundary. (8 to 18 cm thick)

Bw--58 to 97 cm; pale brown (10YR 6/3) very gravelly medial coarse sandy loam, brown (10YR 4/3) moist; weak medium granular structure; soft, very friable, nonsticky and nonplastic; many very fine, fine, medium and coarse roots; many very fine and fine interstitial pores; 45 percent gravel, 3 percent cobbles, moderately acid (pH 5.6); diffuse wavy boundary. (28 to 46 cm thick)

Cr--97 cm; weathered andesitic tuff, fractures greater than 10 centimeters apart with some roots and soil in cracks.

TYPE LOCATION: Placer County, California; Lake Tahoe Basin; 30 meters south of Blackwood Canyon Road, S 1/2 of section 34, T.15 N., R.16 E., MDB&M. 39 degrees N latititude, 5 degrees, 54 seconds, 120 degrees W longitude, 11 minutes, 55 seconds. U.S.G.S. Quad: Homewood, California

RANGE IN CHARACTERISTICS:

Soil moisture: Soils are usually moist between 25 and 84 cm and are dry in all parts for about 55 days between late August and early October

Soil temperature: The mean annual soil temperature is 4 to 8 degrees C, and the mean annual summer soil temperatures vary from 10 to 13 degrees C.

Umbric epipedon: 25 to 61 cm thick though dark colors normally extend to only 50 cm

Depth to a paralithic contact: 50 to 100 cm

Texture of the fine earth: sandy loam, coarse sandy loam or loam and has less than 18 percent clay

Rock fragments: average more than 35 percent throughout the control section but ranges from 15 to 70 percent in individual horizons. Rock fragments are mainly gravel size but include cobbles and stones.

Ash content: less than 60 percent vitric pyroclastic material in the upper 36 centimeters

Bulk density: range from 0.70 gm/cc to 0.95 gm/cc

Base saturation: commonly is 15 to 30 percent but varies from 3 to 50 percent.

The A horizon:

Hue: 10YR or 7.5 YR
Value: 3 through 5 dry, 2 through 4 moist
Chroma: 2 through 4 dry or moist

Organic matter: ranges from 2 to 34 percent
Reaction: strongly to slightly acid.

The Bw horizon:

Hue: 10YR or 7.5YR
Value: 4 through 7 dry, 3 through 5 moist
Chroma: 3 through 8 dry, 2 through 4 moist

Reaction: moderately acid or strongly acid

COMPETING SERIES: At this time there are no other series in this family.

GEOGRAPHIC SETTING: The Waca soils are on gently sloping to very steep mountains. Elevations range from 1825 to 2740 meters and down to 1675 meters on some north aspects. These soils formed in material weathered from andesitic tuff breccia. Most of the soils have formed in materials weathered from mudflows or debris flows of the Merhten Formation. The climate is humid to subhumid with warm dry summers and cold wet winters. Mean annual precipitation is 580 to 2035 mm, most of which occurs as snow. Mean annual temperature is 3 to 9 degrees C. Mean January temperature is -1 degrees C, mean July temperature is 16 degrees C. Frost-free season is 25 to 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Campone, Longval, Lyonman, Melody, Sky, Smokey, Tourn and Windy soils. Smokey soils have ochric epipedons. Campone, Lyonman and Tourn soils have mollic epipedons. Longval soils have mixed mineralogy and less than 35 percent rock fragments in the textural control section. Sky and Melody soils have a cryic temperature regime and Melody soils are less than 50 cm to bedrock. All these soils are on similar landforms.

DRAINAGE AND PERMEABILITY: Well drained; medium to high runoff; moderately rapid permeability above the paralithic contact.

USE AND VEGETATION: Timber production and watershed; native vegetation is mixed conifers. The principal species are red fir, white fir, mountain hemlock, and western white pine.

DISTRIBUTION AND EXTENT: These soils occur in mountainous areas of Northern California and are extensive. MLRA 22A

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Placer County (Tahoe Basin Area), California, 1970.

REMARKS: The exchange complex is dominated by amorphous materials. Soils that were mapped as Waca in soil survey areas with elevations less than 1675 meters would now be outside the concept for the Waca series.

Diagnostic horizons and features recognized in this pedon are:

Umbric epipedon - 5 to 58 cm (A1, A2, A3 horizons)

Andic soil properties - 5 to 97 cm.

Paralithic contact - at 97 cm

Particle-size control section - 5 to 97 cm.

ADDITIONAL DATA: "Soil Survey Investigation Report No. 24," June 1973, pp 342-343, Waca cobbly coarse sandy loam (S68 CA-61-001). Andic soil property tests were run on archived samples from type location in 1994. "Soils-13 Review of Laboratory Data of Pedons Formed on Mehrton Formation, Central Sierra Mountain, California," April 24, 1978, Dr. Wiley D. Nettleton.

Series reclassified 10/96.

National Cooperative Soil Survey
U.S.A.