LOCATION LONGLAKE AK
Established Series
SDB
08/2025
LONGLAKE SERIES
Depth class: very deep
Drainage class: somewhat poorly drained
Parent material: mossy organic material over silty loess over loamy till
Landscape: foothills
Landform: drainageways and till plains
Slope: 0 to 8 percent
Mean annual precipitation: about 600 mm (24 in)
Mean annual air temperature: about -3 degrees C (27 degrees F)
Frost-free period: 32 to 71 days
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive Fluvaquentic Haplocryepts
TYPICAL PEDON: Longlake silt loam in a grass and willow community on a northwest facing till plain drainage, on a 3 percent slope at an elevation of 1178m (3865 ft)
Oi--0 to 12 cm (0 to 5 in); slightly decomposed plant material, dark brown (10YR 3/3) broken face moist; many very fine, fine, and few medium roots throughout; very strongly acid (pH 4.9); clear wavy boundary (10 to 14 cm, 4 to 6 in)
Bw1--12 to 34 cm (5 to 13 in); silt loam, dark yellowish brown (10YR 3/4) broken face moist; moderate medium subangular blocky structure; soft, very friable, slightly sticky, slightly plastic; nonsmeary; common very fine, fine, and medium roots throughout; very fine and fine dendritic tubular pores; moderately acid (pH 5.7); gradual wavy boundary (18 to 25 cm, 7 to 10 in)
Bw2--34 to 67 cm (13 to 26 in); silt loam, brown (10YR 4/3) broken face moist; moderate coarse subangular blocky structure; soft, very friable, slightly sticky, slightly plastic; nonsmeary; common very fine, fine, and few medium roots throughout; very fine and fine dendritic tubular pores; 10 percent fine distinct irregular dark grayish brown (2.5Y 4/2) masses of oxidized iron and 30 percent coarse distinct irregular dark yellowish brown (10YR 3/6) iron depletions; moderately acid (pH 5.8); abrupt wavy boundary (25 to 35 cm, 10 to 14 in)
2C--67 to 150 cm (26 to 59 in); very gravelly loam, dark yellowish brown (10YR 3/4) broken face moist; weak fine granular structure; soft, very friable, slightly sticky, nonplastic; nonsmeary; few very fine roots throughout; interstitial pores; 15 percent cobbles by volume, 35 percent gravels by volume; moderately acid (pH 6.0). (76 to 97 cm, 30 to 38 in)
TYPE LOCATION: Valdez-Cordova Census Area County, Alaska; latitude 63.08465, longitude -145.45305, UTM 6995960.78 north and UTM 578124.56 east, zone 6, Datum WGS84.
RANGE IN CHARACTERISTICS:
Soil moisture regime: udic
Soil temperature regime: cryic
Mean annual soil temperature: 0 to 4 degrees C. (32 to 39.2 degrees F)
Thickness of organic material: 10 to 14 cm (4 to 6 in)
Thickness of ochric epipedon: 10 to 14 cm (4 to 6 in)
Thickness of cambic horizon: 18 to 25 cm (7 to 10 in)
Depth to aquic conditions: 28 to 39 cm (11 to 15 in)
Depth to redoximorphic concentrations: 28 to 39 cm (11 to 15 in)
Depth to redoximorphic depletions: 28 to 39 cm (11 to 15 in)
Depth to lithologic discontinuity: 53 to 74 cm (21 to 29 in)
Oi or Oe horizon:
Hue: 7.5YR or 10YR
Value: 2 to 3
Chroma: 1 to 3
Texture: slightly decomposed organic material, moderately decomposed organic material
Organic matter: 60 to 90 percent
Reaction class: very strongly acid to moderately acid (pH 5.0 to 6.0)
Bw1or Bw2 horizon:
Hue: 10YR or 2.5Y
Value: 3 to 4
Chroma: 3 to 4
Texture: silt loam
Sand: 20 to 40 percent
Silt: 50 to 72 percent
Clay: 8 to 17 percent
Organic matter: 4 to 6 percent
Reaction class: strongly acid to slightly acid (pH 5.1 to 6.4)
2C horizon:
Hue: 10YR or 2.5Y
Value: 3 to 5
Chroma: 2 to 4
Texture: Gravelly loam, very gravelly loam
Sand: 40 to 50 percent
Silt: 28 to 50 percent
Clay: 10 to 25 percent
Rock fragments: 30 to 60 percent
Gravels: 20 to 40 percent
Cobbles: 10 to 20 percent
Organic matter: 1 to 3 percent
Reaction class: strongly acid to neutral (pH 5.5 to 6.8)
COMPETING SERIES: There are no competing series
GEOGRAPHIC SETTING:
Elevation: 800 to 1600 meters (2625 to 5250 ft)
Parent material: mossy organic material over silty loess over loamy till
Landform: drainageways and till plains
Slopes: 0 to 8 percent
Mean annual precipitation: 400 to 800 mm (16 to 31 in)
Mean annual air temperature: -4 to -2 degrees C. (25 to 28 degrees F)
Frost-free period: 32 to 71 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Ahtell,
Cirquecreek, and Stibnite series.
Ahtell soils are well drained, lack permafrost, have folistic and umbric epipedons, and occur on hill tops, and hillside positions.
Cirquecreek soils are well drained, lack a cambic horizon, and occur on saddles and mountain slopes
Stibnite soils are well drained, lack a lithologic discontinuity, and occur in till plains, mountains, kames and kettles.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class: somewhat poorly
Saturated Hydraulic Conductivity: very high in the Oi horizon, moderately high in the Bw1 and Bw2 horizons, and high in the 2C horizon
Permeability: very rapid in the Oi horizon, moderate in the Bw1 and Bw2 horizons, moderately rapid in the 2C horizon.
Runoff: very high
USE AND VEGETATION:
Use: wildlife habitat, recreation, and subsistence
Native vegetation: reed polargrass, little tree willow, tealeaf willow, moss
DISTRIBUTION AND EXTENT: MLRA 228 Interior Alaska mountains.
Extent: limited
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Wasilla, Alaska
SERIES ESTABLISHED: North Copper River Soil Survey, Alaska, 2024.
REMARKS: Diagnostic features and horizons recognized in this profile include:
Particle-size control section: 37 to 112 cm (15 to 44 in)
Aquic conditions: 34 to 67 cm (13 to 26 in) (Bw2 horizon)
Ochric epipedon: 0 to 12 cm (0 to 5 in) (Oi horizon)
Cambic horizon: 12 to 34 cm (5 to 13 in) (Bw1 horizon)
Redoximorphic concentrations: 34 to 67 cm (13 to 26 in) (Bw2 horizon)
Redoximorphic depletions: 34 to 67 cm (13 to 26 in) (Bw2 horizon)
Lithologic discontinuity: 67 to 150 cm (26 to 59 in) (2C horizon)
ADDITIONAL DATA:
User pedon Id: 2023AK261278
National Cooperative Soil Survey
U.S.A.