LOCATION HETERWA                 CO

Established Series
Rev. WPT-GB-KLS
03/2023

HETERWA SERIES

The Heterwa series consists of moderately deep, well drained, moderately permeable soils that formed in basaltic and volcanic ash materials and in glacial material from basalt. These soils are on high plateaus, rolling mesa tops, and flat mountain tops and have slopes ranging from 0 to 35 percent. The mean annual precipitation is about 810 mm, and the mean annual air temperature is about 3 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, active, frigid Inceptic Hapludults

TYPICAL PEDON: Heterwa loam - alpine timberline. (Colors are for air dry soil unless otherwise noted.)

Oe--0 to 5 cm; decomposing organic material, principally needles, leaves, roots and twigs.

A--5 to 15 cm; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist, weak coarse subangular blocky structure parting to moderate fine granular; slightly hard, very friable, slightly sticky nonplastic; 5 percent gravel, 5 percent cobble, 1 percent stone; very strongly acid; clear smooth boundary. (8 to 15 cm thick)

E--15 to 30 cm; pink (7.5YR 7/4) silt loam, brown (7.5YR 5/4) moist; weak coarse platy structure parting to moderate medium and coarse granular; slightly hard, friable, slightly sticky, slightly plastic; 5 percent gravel, 5 percent cobble, 1 percent stone; very strongly acid; clear wavy boundary. (10 to 25 cm thick)

E/B--30 to 50 cm; E part (60 percent) is pink (7.5YR 7/4) gravelly loam, brown (7.5YR 5/4) moist and B part (40 percent) is brown (7.5YR 5/4) very gravelly clay loam, brown (7.5YR 4/2) moist that consists of intermixed blotches and fingers of the E material above and clayey material in the B horizon below; E portion has weak coarse platy structure parting to moderate medium and coarse granules; slightly hard, friable; B portion has moderate fine and medium subangular blocky structure; slightly hard, friable, sticky, plastic; 25 percent gravel, 10 percent cobble, 2 percent stones; very strongly acid; clear wavy boundary. (15 to 30 cm thick)

Bw--50 to 75 cm; brown (7.5YR 5/4) very gravelly clay loam, brown (7.5YR 4/2) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, sticky and plastic; 30 percent gravel, 20 percent cobble, 3 percent stone; very strongly acid; clear wavy boundary. (18 to 30 cm thick)

R--75 cm; hard fractured basaltic bedrock.

TYPE LOCATION: Garfield County, Colorado; about 45 meters east and 335 meters north of the southwest corner of Sec. 7, T. 2 S., R. 87 W. or about 1400 meters southeast of Shingle Peak in the Flat Tops Wilderness Area, in an unsectionized area. U.S.G.S. Trappers Lake quad.; lat. 39 degrees, 53 minutes, 33 seconds N., and long. 107 degrees, 12 minutes, 15 seconds W.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature--4 to 7 degrees C
Mean summer soil temperature--7 to 8 degrees C
Depth to bedrock--50 to 100 cm
The thin A horizon may be missing in some pedons.

Particle-size control section:
Texture--loam, clay loam, or sandy clay loam
Clay content--20 to 35 percent
Rock fragment content--35 to 80 percent total and are mainly gravel, but also includes 5 to 20 percent cobble and less than 5 percent stone
Reaction--pH 4.5 to 6.0

A horizon when present
Hue--2.5Y through 7.5YR
Value--4 or 5 dry, 2 or 3 moist
Chroma--2 or 3

E horizon
Hue--10YR or 7.5YR
Value--5 through 7 dry, 4 through 6 moist
Chroma--2 through 4

The E/B horizon has colors of the E and Bw horizons.

Bw horizon
Hue--10YR through 5YR
Value--5 or 6 dry, 4 or 5 moist
Chroma--2 through 4
Texture--loam, sand clay loam or clay loam

COMPETING SERIES: These are the Bensley (OR), Endlich (CO), Grenadier (CO), Henson (CO), Ivywild (CO), Jeru (ID), Klootch (ID), Koffgo (ID), Leighcan (WY), Marsell (UT), Oatman (OR), and Snotown (NV) series. Endlich and Snotown soils have less than 20 percent clay in the particle-size control section. In addition, the Endlich soils have more moisture and longer durations with increased moisture in the soil moisture control section. Ivywild soils have paralithic contact at a depth of 50 to 100 cm. Klootch soils are moderately acid to neutral. Bensley, Grendier, Henson, Jeru, Koffgo, Leighcan, Marsell, and Oatman soils lack bedrock above 100 cm.

GEOGRAPHIC SETTING:
Landform--high plateaus and flat mountain tops
Elevation--3050 to 3425 meters
Slope--0 to 35 percent
Parent material--glacial till and residuum of medium to moderately fine textured material from volcanic basalt flows and ash
Mean annual precipitation--760 to 1000 mm, the majority of which is received as snow
Mean annual air temperature--0 to 4 degrees C
Frost-free period--45 to 60 days

GEOGRAPHICALLY ASSOCIATED SOILS: None listed.

DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderate permeability.

USE AND VEGETATION: Heterwa soils are used for wildlife habitat, recreation and limited short duration sheep grazing. Native vegetation includes open stands of stunted spruce-fir with open areas of alpine grasses, sedges, shrubs and forbs.

DISTRIBUTION AND EXTENT: Heterwa soils are moderately extensive in the mountainous alpine areas of western Colorado; MLRA 48A.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Garfield County, (Flat Tops Soil Survey Area), Colorado, 1984. The Heterwa series was proposed in 1981 in the wilderness area of the Flat Tops Soil Survey Area in Garfield County, Colorado. Series name is taken from location of typical pedon at headwater areas of the South Fork of White River.

REMARKS: Diagnostic horizons and features recognized in this pedon include:
Low base saturation throughout the profile.
Cambic horizon--50 to 75 cm (Bw horizon)
Lithic contact--75 cm to hard bedrock (R horizon)
Particle-size control section--25 to 75 cm (part of the E horizon and all of the E/B and Bw horizons)

Converted to metric and O horizons were updated to start at zero. Competing series section was not updated. 01/2023

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National Cooperative Soil Survey
U.S.A.