LOCATION CHEMWASH                CA

Established Series
Rev: CMB/LJL/CAH/ET
12/2015

CHEMWASH SERIES

The Chemwash series consists of very deep, excessively drained soils that formed in alluvium derived from mixed igneous and/or metamorphic rocks. Chemwash soils are on inset fans, fan aprons, alluvial fans and drainageways. Slopes range from 2 to 8 percent. The mean annual precipitation is about 75 millimeters (about 3 inches) and the mean annual temperature is about 25 degrees C (77 degrees F).

TAXONOMIC CLASS: Sandy-skeletal, mixed, hyperthermic Typic Torriorthents

TYPICAL PEDON: Chemwash very gravelly loamy coarse sand, on a 2 percent slope under desert shrubs at an elevation of 157 meters (about 510 feet). (Colors are for dry soil unless otherwise noted.) The soil surface is covered by approximately 30 percent fine gravel and 5 percent medium and coarse gravel, and 1 percent cobbles.

A--0 to 6 centimeters (0 to 2 inches); yellowish brown (10YR 5/4) very gravelly loamy coarse sand, brown (10YR 5/3) moist; massive; soft, very friable, nonsticky and nonplastic; many fine roots; common fine irregular pores; 30 percent fine gravel and 5 percent medium and coarse gravel; slightly effervescent; moderately alkaline (pH 8.2); abrupt smooth boundary. (3 to 7 centimeters thick)

C1--6 to 20 centimeters (2 to 8 inches); pale brown (10YR 6/3) gravelly loamy sand, brown (10YR 5/3) moist; massive; soft, very friable, nonsticky and nonplastic; many very fine roots; common very fine irregular pores; 10 percent fine gravel and 5 percent medium and coarse gravel; slightly effervescent; moderately alkaline (pH 8.2); clear wavy boundary.

C2--20 to 38 centimeters (8 to 15 inches); pale brown (10YR 6/3) very gravelly coarse sand, brown (10YR 5/3) moist; single grain; loose, nonsticky and nonplastic; many very fine, common medium and coarse roots; common very fine irregular pores; 25 percent fine gravel and 10 percent medium and coarse gravel; strongly effervescent; moderately alkaline (pH 8.2); abrupt wavy boundary.

C3--38 to 63 centimeters (15 to 25 inches); pale brown (10YR 6/3) very gravelly coarse sand, yellowish brown (10YR 5/4) moist; massive; slightly hard, very friable, nonsticky and nonplastic; many fine and medium roots; common very fine irregular pores; 40 percent fine gravel and 10 percent medium and coarse gravel; strongly effervescent; moderately alkaline (pH 8.2); abrupt smooth boundary.

C4--63 to 113 centimeters (25 to 45 inches); light yellowish brown (10YR 6/4) stratified very gravelly coarse sand to extremely gravelly coarse sand, brown (10YR 5/3) moist; massive; moderately hard, very friable, nonsticky and nonplastic; many medium roots; common very fine irregular pores; averages 40 percent fine gravel and 10 percent medium and coarse gravel; slightly effervescent; moderately alkaline (pH 8.2); abrupt smooth boundary.

C5--113 to 170 centimeters (45 to 67 inches); yellowish brown (10YR 5/4) very gravelly coarse sand, brown (10YR 5/3) moist; massive; moderately hard, very friable, nonsticky and nonplastic; common very fine irregular pores; 35 percent fine gravel and 5 percent medium and coarse gravel; very slightly effervescent; moderately alkaline (pH 8.0). (Combined thickness of the C horizons is 140 to 175 centimeters.)

TYPE LOCATION: San Bernardino County, California; about 10 kilometers west-southwest of Lake Havasu City, Arizona at the east end of Chemehuevi Wash; approximately 1.5 kilometers south and 1/2 kilometer west of Havasu Lake, California; 230 meters south and 200 meters east of the northwest corner of section 1, T. 4 N., R. 24 E.; USGS Havasu Lake, California-Arizona 7.5 minute topographic quadrangle; 34 degrees, 28 minutes, 6.84 seconds north latitude and 114 degrees, 25 minutes, 22.08 seconds west longitude; UTM 11S 736712e 3817126n (DTM: NAD83).

RANGE IN CHARACTERISTICS:

Soil moisture control section: usually dry throughout, rarely moist in some part during summer or winter. The soils have a typic-aridic soil moisture regime.

Soil temperature: 25 to 28 degrees C. (about 77 to 82 degrees F.)
Organic matter: 0 to 0.5 percent.

Control section
Clay content: 1 to 6 percent.
Rock fragments: averages 35 to 60 percent, ranges from 15 to 75 percent in individual layers, with more than half of the gravel 2 to 5 millimeters in size with 0 to 15 percent cobbles or stones.

A horizon
Value: 5 through 7 dry, 4 or 5 moist.
Chroma: 2 through 4, dry or moist.
Texture of the fine earth: coarse sand or loamy coarse sand.
Clay content: 1 to 8 percent.
Rock fragments: 15 to 60 percent, dominated by fine gravel.
Effervescence: noneffervescent through strongly effervescent.
Reaction: slightly alkaline or moderately alkaline.

C or Ck horizons
Hue: 10YR or 7.5YR.
Value: 5 or 6 dry, 4 or 5, moist.
Chroma: 2 through 4, dry or moist.
Texture of the fine earth fraction: coarse sand, sand, loamy coarse sand, or loamy sand.
Structure: massive or single grain.
Consistence: soft or loose.
Rock fragments: averages 35 to 60 percent, ranges from 15 to 75 percent in individual layers, dominated by fine gravel with
0 to 15 percent cobbles or stones.
Effervescence: noneffervescent through strongly effervescent.
Reaction: slightly or moderately alkaline.
Other features: few very thin, randomly oriented calcium carbonate coats occur on rock fragments in some pedons.

COMPETING SERIES: These are the Carrizo (CA), Carrwash (NV), Descent (CA), Goldenhills (CA), and Rizzo (CA) series. Carrizo and Carrwash soils are moist for 10 to 20 days in the moisture control section. Carrwash soils have a MAST of 22 to 24 degrees C. Carrizo and Rizzo soils are dominated by medium and coarse gravel with more than half of the rock fragments being medium gravel-sized or larger. Descent soils are dominated by channers and flagstones and have a calcium carbonate equivalent between 5 and 15 percent throughout the series control section. Goldenhills soils have a mean annual soil temperature of 22 to 25 degrees C, formed in colluvium and residuum, are deep to a lithic contact and have a C horizon with greater than 80 percent cover at the soil surface.

GEOGRAPHIC SETTING: Chemwash soils are on inset fans, fan aprons, alluvial fans, and drainageways. Slopes range from 2 to 8 percent. These soils formed in alluvium derived from igneous and/or metamorphic rocks. Elevations are 140 to 835 meters (about 460 to 2,740 feet). The climate is arid with hot, dry summers and warm, dry winters. The mean annual precipitation is 50 to 100 millimeters (about 2 to 4 inches); mean annual air temperature is 23 to 26 degrees C (about 73 to 79 degrees F), and the frost free season is 360 to 365 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Carsitas, Goldrose and Rizzo soils. Carsitas and Goldrose soils occur on alluvial fans, and Carsitas soils have a sandy particle size control section. Goldrose soils have a sandy particle size control section, but include one horizon that has greater than 35 percent rock fragments. Rizzo soils occur on similar landforms and are dominated by medium-sized gravel or larger rock fragments.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Excessively drained; very low to low runoff; high saturated hydraulic conductivity.

USE AND VEGETATION: These soils are used for rangeland and wildlife habitat. The present vegetation is mainly creosote bush, brittlebush, burrobrush, blue paloverde, and desert lavender.

DISTRIBUTION AND EXTENT: Lower Colorado Desert of southeastern California, U.S.A.; MLRA 31. These soils are not extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: PHOENIX, ARIZONA

SERIES ESTABLISHED: San Bernardino County, California; Chemehuevi Wash Off-Highway Vehicle Area, part of the Colorado Desert Soil Survey Area, 2012. The name is coined from Chemehuevi Wash located in Chemehuevi Valley.

REMARKS: Diagnostic horizons and features in this pedon include:

Ochric epipedon - from a depth of 0 to 6 centimeters (0 to 2 inches) (A horizon).
Particle-size control section - from a depth of 25 to 100 centimeters (10 to 40 inches) (Part of the C2, C3 and part of the C4 horizons).

ADDITIONAL DATA: NASIS Pedon User ID: 6799-149-9CB.

Responsibility for this series was transferred from Davis to Phoenix 12/2015. The last revision to the series was 6/2012. ET

---

National Cooperative Soil Survey
U.S.A.