LOCATION HOPEVAL CAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive Cumulic Cryaquolls
TYPICAL PEDON: Hopeval very fine sandy loam--rangeland. (Colors are for moist soil unless otherwise noted.)
A1--0 to 2 inches; very dark brown (10YR 2/2) very fine sandy loam, dark grayish brown (10YR 4/2) dry; strong fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine roots; common very fine interstitial and tubular pores; slightly acid; clear wavy boundary. (2 to 6 inches thick)
A2--2 to 12 inches; very dark brown (10YR 2/2) loam, dark grayish brown (10YR 4/2) dry; moderate fine granular structure; soft, very friable, slightly sticky and slightly plastic; common very fine roots and few fine; common very fine interstitial and tubular pores; slightly acid; clear wavy boundary. (6 to 12 inches thick)
A3--12 to 15 inches; very dark grayish brown (10YR 3/2) loam, grayish brown (10YR 5/2) dry; common fine distinct dark yellowish brown (10YR 3/4) irregular soft iron masses throughout; moderate fine and medium subangular blocky structure; soft, very friable, slightly sticky and nonplastic; common very fine roots and few fine; common very fine interstitial and tubular pores; slightly acid; clear wavy boundary. (3 to 12 inches thick)
A4--15 to 26 inches; very dark grayish brown (10YR 3/2) stratified fine sand to sandy loam, grayish brown (10YR 5/2) dry; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine roots and few fine; common very fine interstitial and tubular pores; many fine distinct dark yellowish brown (10YR 3/4) irregular masses of iron accumulation in the matrix; slightly acid; clear wavy boundary. (0 to 12 inches thick)
C1--26 to 33 inches; dark grayish brown (10YR 4/2) stratified fine sandy loam to gravelly coarse sand, light brownish gray (10YR 6/2) dry; massive; soft, very friable, nonsticky and nonplastic; few very fine and fine roots; common very fine interstitial and tubular pores; many medium distinct dark brown (7.5YR 3/4) irregular masses or iron accumulation in the matrix and common medium distinct dark brown (7.5YR 3/4) masses of iron accumulation on rock fragments; 8 percent gravel; slightly acid; abrupt wavy boundary. (6 to 12 inches thick)
2C2--33 to 60 inches; dark grayish brown (10YR 4/2) stratified very gravelly coarse sand, light brownish gray (10YR 6/2) dry; single grain; loose, nonsticky and nonplastic; few very fine and fine roots; many very fine and fine interstitial pores; common fine faint black (10YR 2/1) irregular masses of manganese accumulation in the matrix and common coarse prominent dark reddish brown (5YR 3/4) irregular masses of iron accumulation in the matrix; 55 percent gravel; slightly acid.
TYPE LOCATION: Alpine County, California; on the Toiyabe National Forest in Hope Valley about 1,000 feet north of Highway 88; approximately 600 feet south and 5,350 feet east of the northwest corner of section 25, T. 10 N., R. 18 E.; USGS Freel Peak 7.5 minute topographic quadrangle; 38 degrees 46 minutes 35.3 seconds north latitude and 119 degrees 55 minutes 51.5 seconds west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually saturated in some part of the moisture control section during winter, spring, and early summer, usually dry in all parts during summer and fall; seasonal periods of aquic moisture regime from November through June during saturation with ground water and anaerobic conditions; Xeric moisture regime.
Mean annual soil temperature - 40 to 44 degrees F.
Mean summer soil temperature - 44 to 47 degrees F.
Mollic epipedon thickness - 20 to 30 inches.
Depth to very gravelly or extremely gravelly material - 24 to 40 inches.
Depth to seasonal aquic conditions - 0 to 20 inches.
Particle-size control section - Clay content: Averages 10 to 18 percent; Rock fragments: Averages 0 to 15 percent in the upper part and 35 to 60 percent in the lower part, mainly gravel. Lithology of fragments are granitic rocks such as granodiorite, volcanic rocks such as tuff, or minor metamorphic rocks such as quartzite.
A1 horizon - Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 1 or 2, dry or moist.
Organic matter content: 4 to 8 percent.
Reaction: Moderately acid or slightly acid.
A2, A3, and A4 horizons (when present) - Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 1 or 2, dry or moist.
Texture: Stratified loam to fine sand.
Organic matter content: 4 to 8 percent.
Reaction: Moderately acid or slightly acid.
Redoximorphic features: Redox concentrations occur as masses of iron or manganese accumulation in the matrix.
C horizons - Hue: 10YR or 2.5Y.
Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 1 or 2, dry or moist.
Texture: Stratified very gravelly coarse sand to loam.
Clay content: Averages 5 to 15 percent clay.
Rock fragments: Averages 35 to 60 percent.
Reaction: Moderately acid or slightly acid.
Redoximorphic features: Redox concentrations occur as masses of iron or manganese accumulation in the matrix or as coats on rock fragments.
COMPETING SERIES: These are the Dobrow and Moosejaw (T) series.
Dobrow soils do not have a xeric moisture regime and have mean summer soil temperature of about 56 degrees F. Moosejaw soils have persistent saturation between the soil surface and a depth of 16 inches and have an organic surface horizon.
GEOGRAPHIC SETTING: Hopeval soils are on flood plains and stream terraces. They formed in alluvium and outwash derived from mixed rocks. Slopes are 0 to 8 percent. Elevations range from 7,000 to 10,000 feet. The climate is subhumid-continental with cold, moist winters and cool, dry summers. The mean annual precipitation is 30 to 50 inches, mean annual temperature is 36 to 39 degrees F., and the frost-free period is 30 to 60 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Burnlake and Cavebear soils. Burnlake soils are loamy-skeletal, have umbric epipedons, do not have aquic conditions, and occur on moraines. Cavebear soils are sandy-skeletal, do not have aquic conditions within 20 inches of the surface, and occur on adjacent stream terraces.
DRAINAGE AND PERMEABILITY: Poorly drained and very poorly drained; very high surface runoff; moderate permeability (moderately high or high saturated hydraulic conductivity). Endosaturation is present with an apparent seasonal high water table between the soil surface and 20 inches (very shallow or shallow free water occurrence classes) from November through June. Cumulative annual duration classes are Common or Persistent. Some areas of these soils are susceptible to occasional flooding for brief periods between December and June.
USE AND VEGETATION: Hopeval soils are used for rangeland, recreation, watershed, and wildlife habitat. The native vegetation is mainly sedges and rushes.
DISTRIBUTION AND EXTENT: Eastern California, on the east side of the Sierra Nevada Range. These soils are not extensive with about 5,900 acres of the series mapped to date. MLRA 22A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Alpine County (Toiyabe National Forest Area), California, 2006.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 26 inches (A1, A2, A3, and A4 horizons).
Aquic conditions - The conditions of endosaturation and reduction in horizons between the soil surface and 60 inches at certain times in normal years (A1, A2, A3, A4, C1, and 2C2 horizons).
Particle-size control section - The zone from 10 to 40 inches (A3, A4, and C1 horizons and parts of the A2 and 2C2 horizons).