LOCATION BENCHLAKE CA

Established Series
JBB/CES/JTW
09/2021

BENCHLAKE SERIES

The Benchlake series consists of very shallow and shallow, somewhat excessively or excessively drained soils formed in colluvium and residuum derived from granitic rocks. Benchlake soils are on structural benches of mountain slopes, glacial valley walls, and cirques of the Sierra Nevada Mountains. Slopes range from 5 to 45 percent. Mean annual precipitation is about 1085 millimeters and the mean annual air temperature is about 0 degrees C.

TAXONOMIC CLASS: Sandy-skeletal, isotic Lithic Cryorthents

TYPICAL PEDON: Benchlake very cobbly loamy sand on a west-facing (228 degree), 42 percent slope under subalpine perennial forbs at an elevation of 3,575 meters. (Colors are for dry soil unless otherwise noted. When described on August 5, 2015, the soil was moist to 16 centimeters.)

A1--0 to 14 centimeters; dark grayish brown (10YR 4/2) very cobbly loamy sand, very dark grayish brown (10YR 3/2) moist; 1 percent clay; weak fine granular structure; very friable, soft, slightly sticky, nonplastic; many very fine roots throughout; common very fine and fine irregular pores; 15 percent subangular indurated granitoid gravel, 20 percent subangular indurated granitoid cobbles; NaF pH 9.0; very strongly acid (pH 4.7); abrupt smooth boundary.

A2--14 to 16 centimeters; brown (10YR 5/3) very gravelly loamy coarse sand, brown (10YR 4/3) moist; 1 percent clay; weak fine granular structure; very friable, soft, nonsticky, nonplastic; common very fine roots throughout; common very fine and fine irregular pores; 30 percent subangular indurated granitoid gravel, 10 percent subangular indurated granitoid cobbles; NaF pH 9.5; strongly acid (pH 5.2); very abrupt smooth boundary. (Combined thickness of the A horizons is 10 to 30 cm)

R--16 to 26 centimeters; indurated granodiorite bedrock, fractured at intervals of greater than 200 cm; many very fine roots in mat on top of horizon.

TYPE LOCATION: Tulare County, California, near Lake South America in Sequoia National Park; USGS 7.5 minute topographic quadrangle: Mount Brewer, California; WGS84 36.677082 latitude and -118.411713 longitude; UTM zone 11 4059979 meters N 373859 meters E NAD83.

RANGE IN CHARACTERISTICS:
Soil Temperature: The mean annual soil temperature at 50 centimeters is 0 to 6 degrees C, and the difference between mean summer and mean winter soil temperatures is greater than 6 degrees C. The soils have a cryic soil temperature regime.

Soil Moisture: The soils have a xeric soil moisture regime. The soil moisture control section is dry in all parts from about August to October (about 80 days).

Diagnostic Feature(s):
Ochric epipedon thickness: 6 to 18 cm
Depth to lithic contact: 10 to 50 cm

Reaction: very strongly to moderately acid

Base Saturation: less than 50 percent (by sum of cations)

Particle size control section weighted average:
Rock fragments: 35 to 75 percent, with 15 to 60 percent gravel, 0 to 20 percent cobbles, and 0 to 20 percent stones.
Clay content: 1 to 6 percent
NaF pH: 9.0 to 11.0

A horizons:
Hue: 10YR, 2.5Y
Value: 4 to 6 dry, 2 or 3 moist
Chroma: 2 or 3, dry or moist
Texture: sand, loamy sand, loamy coarse sand, sandy loam
Clay content: 1 to 8 percent
Rock fragments: 15 to 85 percent
15 to 50 percent gravel
0 to 20 percent cobbles
0 to 20 percent stones

Bw horizons, where present:
Hue: 10YR
Value: 4 to 6 dry, 2 to 4 moist
Chroma: 3 to 6, dry or moist
Texture: loamy sand, loamy coarse sand, sandy loam
Clay content: 1 to 10 percent
Rock fragments: 15 to 80 percent
15 to 60 percent gravel
0 to 20 percent cobbles
0 to 20 percent stones

C horizons, where present:
Hue: 10YR, 2.5Y
Value: 5 to 7 dry, 3 to 5 moist
Chroma: 2 to 4, dry or moist
Texture: loamy sand, loamy coarse sand, coarse sand
Clay content: 0 to 5 percent
Rock fragments: 20 to 80 percent
15 to 70 percent gravel
0 to 20 percent cobbles
0 to 20 percent stones

COMPETING SERIES: There are no other series in this family at this time.

GEOGRAPHIC SETTING: Benchlake soils are on linear to slightly convex positions on structural benches and backslope positions on cirques, glacial valley walls, and mountain slopes. Slopes are 5 to 45 percent. Elevations are 2550 to 4365 meters. These soils formed in colluvium and residuum derived from granitic rocks. The climate is Mediterranean with warm, dry summers and cold, moist winters. The mean annual precipitation is 685 to 1505 millimeters and the mean annual air temperature is -3 to 6 degrees C. The frost free period is 40 to 110 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Canisrocks and Langille soils. Canisrocks soils are on talus slopes and are greater than 200 cm to a lithic contact. Langille soils are on glacial valley walls or glacial valley floors and are 50 to 100 cm to a lithic contact.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat excessively or excessively drained; high saturated hydraulic conductivity. Saturated hydraulic conductivity of the bedrock is very low to high.

USE AND VEGETATION: This soil is used for recreation, wildlife habitat, and watershed. Vegetation includes lodgepole pine, whitebark pine, Parry's rush, and threadleaf sedge.

DISTRIBUTION AND EXTENT: Sierra Nevada Mountains of California; MLRA 22A. These soils are moderately extensive.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Davis, California

SERIES PROPOSED: Tulare County, California in Sequoia and Kings Canyon National Parks. Source of name from from Bench Lake in Kings Canyon National Park.

REMARKS:
Particle Size Control Section for this pedon: 0 to 16 cm
Diagnostic horizons and features recognized in this pedon are:
Ochric Epipedon 0 to 16 cm
Lithic Contact 16 cm

ADDITIONAL DATA:
NASIS User Pedon ID: 2015CA7923078

Soil classified using the 12th Edition of the Keys to Soil Taxonomy.

National Cooperative Soil Survey
U.S.A.