LOCATION TENMILERIVER            AK

Tentative Series
SAS/CBB
04/2026

TENMILERIVER SERIES

Depth class: very deep
Drainage class: well drained
Parent material: ash influenced silty colluvium over gravelly loamy colluvium derived from sandstone
Landscape: mountains, hills
Landform: mountain slopes, hillslopes
Slopes: 10 to 65 percent
Mean annual precipitation: about 400 mm (16 in)
Mean annual air temperature: about -4 degrees C. (25 degrees F.)
Frost-free period: 70 to 90 days

TAXONOMIC CLASS: Medial over loamy-skeletal, amorphic over mixed, superactive, acid, subgelic Andic Humigelepts

TYPICAL PEDON: Tenmileriver highly organic medial silt in a black spruce open forest on an east facing convex, linear backslope on a slope of 31 percent at an elevation of 205 m (673 ft)

Oe--0 to 8 cm (0 to 3 in); moderately decomposed plant material, black (5YR 2.5/1) broken face moist, gray (5YR 5/1) broken face dry; nonsticky, nonplastic; nonsmeary; many very fine and fine and few medium roots throughout; extremely acid (pH 3.8); clear irregular boundary. (6 to 14 cm, 2 to 6 in thick)

A--8 to 38 cm (3 to 15 in); highly organic medial silt, 60 percent black (7.5YR 2.5/1) broken face and 40 percent very dusky red (7.5R 2.5/2) broken face moist, 60 percent gray (7.5YR 5/1) broken face and 40 percent weak red (7.5R 5/2) broken face dry; weak coarse subangular blocky structure; friable, slightly hard, nonsticky, nonplastic; weakly smeary; common very fine and few fine roots throughout; very fine tubular pores; 5 percent gravel; about 15 percent OM ; very strongly acid (pH 4.8); clear irregular boundary. (18 to 35 cm, 7 to 14 in thick)

2Bw--38 to 60 cm (15 to 24 in); very gravelly sandy loam, dark brown (7.5YR 3/2) broken face moist, brown (7.5YR 5/2) broken face dry; weak fine subangular blocky structure; friable, slightly hard, slightly sticky, nonplastic; nonsmeary; few very fine roots throughout; very fine and fine tubular pores; 40 percent gravel; about 5 percent OM; very strongly acid (pH 4.6); clear smooth boundary. (15 to 50 cm, 6 to 20 in thick)

2C--60 to 200 cm (24 to 79 in); very gravelly sandy loam, brown (10YR 4/3) broken face moist, pale brown (10YR 6/3) broken face dry; structureless massive; friable, slightly hard, slightly sticky, nonplastic; nonsmeary; many very fine and fine and few medium roots throughout; fine tubular pores; 55 percent gravel; about 1 percent OM; very strongly acid (pH 4.8). (101 to 161 cm, 40 to 63 in thick)

TYPE LOCATION: Nulato Hills - Continental Divide and Blackburn Hills Soil Survey Area, Alaska; latitude 64 degrees 10 minutes 21.58 seconds north, longitude 160 degrees 17 minutes 27.61 seconds west, datum WGS84, UTM north 7116890.99 and UTM east 437247.48, zone 4W, datum WGS84.

RANGE IN CHARACTERISTICS:

Soil moisture regime: udic
Soil temperature regime: gelic
Mean annual soil temperature: -1 to 0 degrees C. (30 to 32 degrees F.)
Thickness of organic material: 6 to 14 cm (2 to 6 in)
Thickness of umbric epipedon: 33 to 85 cm (13 to 33 in)
Thickness of andic soil properties: 18 to 35 cm (7 to 14 in)
Depth to lithologic discontinuity: 24 to 49 cm (9 to 19 in)

Oe horizon:
Hue: 5YR, 7.5YR, or 10YR
Value: 2 to 3 moist, 4 to 5 dry
Chroma: 1 to 2
Texture: moderately decomposed plant material
Organic matter: 60 to 90 percent
Reaction class: extremely acid to very strongly acid (pH 3.5 to 5.0)

A horizon:
Hue: 7.5YR, 5YR, 7.5R, or 10YR
Value: 2 to 3 moist, 4 to 5 dry
Chroma: 1 to 2
Texture: highly organic medial silt or silt loam
Sand: 5 to 25 percent
Silt: 65 to 91 percent
Clay: 4 to 10 percent
Rock fragments: 0 to 10 percent
Gravels: 0 to 10 percent
Organic matter: 10 to 19 percent
Reaction class: very strongly acid to strongly acid (pH 4.5 to 5.5)

2Bw horizon:
Hue: 7.5YR or 10YR
Value: 3 to 4 moist, 5 to 6 dry
Chroma: 2 to 3
Texture: gravelly or very gravelly sandy loam or loam
Sand: 28 to 70 percent
Silt: 10 to 50 percent
Clay: 6 to 22 percent
Rock fragments: 15 to 45 percent
Gravels: 15 to 45 percent
Organic matter: 1 to 3 percent
Reaction class: very strongly acid to strongly acid (pH 4.5 to 5.5)

2C horizon:
Hue: 10YR or 2.5Y
Value: 3 to 4 moist, 5 to 6 dry
Chroma: 2 to 4
Texture: very or extremely gravelly sandy loam
Sand: 52 to 75 percent
Silt: 7 to 40 percent
Clay: 8 to 18 percent
Rock fragments: 35 to 70 percent
Gravels: 35 to 70 percent
Organic matter: 0.4 to 2 percent
Reaction class: very strongly acid to strongly acid (pH 4.5 to 5.5)

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING:
Elevation: 100 to 430 meters (330 to 1,410 feet)
Parent material: ash influenced silty colluvium over gravelly loamy colluvium derived from sandstone
Landform: mountain slopes, hillslopes
Slopes: 10 to 65 percent
Mean annual precipitation: 300 to 500 mm (12 to 20 in)
Mean annual air temperature: -6 to -1 degrees C. (21 to 30 degrees F.)
Frost free period: 70 to 90 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ena, Siksrik, Ungalik, Pointcreek, Muskox, and Napaaktuk soils.
Ena soils do not have andic soil properties, have a cryic temperature regime, and occur on hillslopes on backslope and footslope positions.
Siksrik soils do not have andic soil properties, have an ochric epipedon, and occur on hillslopes on backslope and footslope positions.
Ungalik soils do not have andic soil properties, have a mollic epipedon, and occur on mountain slopes on backslope and footslope positions.
Pointcreek soils do not have andic soil properties, have a folistic epipedon, and occur on hillslopes on backslope positions.
Muskox soils do not have andic soil properties, have an umbric epipedon, and occur on hillslopes on backslope positions.
Napaaktuk soils do not have andic soil properties, have a mollic epipedon, and occur on flood plains of valleys.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class: well drained
Saturated Hydraulic Conductivity: very high in the Oe horizon, moderately high to high in the A and 2Bw horizons, and moderately high in the 2C horizon
Permeability: rapid to very rapid in the Oe horizon, moderate to moderately rapid in the A horizon, moderate to rapid in the 2Bw horizon, and slow to moderate in the 2C horizon
Runoff: medium or low

USE AND VEGETATION:
Use: wildlife habitat, recreation, and subsistence
Native vegetation: splendid feather moss, black crowberry, black spruce, Schreber's big red stem moss, lingonberry, bog blueberry, dwarf birch, sphagnum, marsh Labrador tea, greygreen reindeer lichen, beauverd spirea, reindeer lichen, cetraria lichen, woodland horsetail, tealeaf willow, reindeer lichen, cup lichen, cloudberry, and Bigelow's sedge.

DISTRIBUTION AND EXTENT: MLRA 240, Nulato Hills-Southern Seward Peninsula Highlands. The series is of moderate extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Wasilla, Alaska

SERIES ESTABLISHED: Nulato Hills - Continental Divide and Blackburn Hills Soil Survey, Alaska, 2024.

REMARKS: Diagnostic features and horizons recognized in this profile include:

Particle-size control section: 33 to 108 cm (13 to 42 in)

Umbric epipedon: 8 to 60 cm (3 to 24 in) (A and 2Bw horizons)

Andic soil properties: 8 to 38 cm (3 to 15 in) (A horizon)

Lithologic discontinuity: 38 to 200 cm (15 to 79 in) (2Bw and 2C horizons)

ADDITIONAL DATA:

User pedon ID: 2021AK180602

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National Cooperative Soil Survey
U.S.A.