LOCATION SWAMPYLAKES AK
Established Series
SDB/MJS
08/2025
SWAMPYLAKES SERIES
Depth class: very deep
Drainage class: somewhat poorly drained
Parent material: organic material over silty loess over sandy and clayey till
Landscape: foothills and mountains
Landform: mountain slopes, mountain valleys, hillslopes, hills, drainage ways and depressions.
Slope: 5 to 15 percent
Mean annual precipitation: about 600 mm (24 in)
Mean annual air temperature: about -3 degrees C (27 F)
Frost-free period: 32 to 90 days
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive Aquic Haplocryolls
TYPICAL PEDON: Swampylakes gravelly silt loam in a black spruce and resin birch community on south facing a linear, linear backslope on a 7 percent slope at an elevation of 780m (2560 ft).
Oi--0 to 17 cm (0 to 7 in); peat, very dark brown (7.5YR 2.5/3) rubbed moist; nonsticky, nonplastic; many very fine, fine, and common medium roots throughout; extremely acid (pH 4.1); clear smooth boundary (14 to 18 cm, 6 to 7 in)
A--17 to 38 cm (7 to 15 in); gravelly silt loam, black (10YR 2/1) broken face moist; weak fine lenticular structure; slightly hard, friable, nonsticky, nonplastic; nonsmeary; many very fine and fine roots throughout; very fine low-continuity dendritic tubular pores; 20 percent rounded gravel by volume; moderately acid (pH 5.8); abrupt smooth boundary (20 to 22 cm, 8 to 9 in)
Bg--38 to 63 cm (15 to 25 in); sandy clay loam, gray (2.5Y 5/1) broken face moist; moderate medium lenticular structure; moderately hard, firm, nonsticky, nonplastic; nonsmeary; few very fine and fine roots throughout; very fine low-continuity dendritic tubular pores; 5 percent coarse irregular dark yellowish brown (10YR 4/4), moist, iron-manganese masses in matrix and 10 percent coarse irregular iron depletions in matrix; 10 percent rounded gravels by volume; slightly acid (pH 6.4); clear smooth boundary. (6 to 29 cm, 2 to 11 cm)
C--63 to 150 cm (25 to 59 in); sandy loam, dark gray (2.5Y 4/1) broken face moist; massive; slightly hard, friable, nonsticky, nonplastic; nonsmeary; very fine low-continuity dendritic tubular pores; 10 percent rounded gravels by volume; neutral (pH 6.6). (81 to 109 cm, 32 to 43 in)
TYPE LOCATION: North Copper River Soil Survey Area, Alaska; latitude 62.76232, longitude -144.57795, UTM 6961432.74 north and UTM 623657.72 east, zone 6, Datum WGS84.
RANGE IN CHARACTERISTICS:
Soil moisture regime: aquic
Soil temperature regime: frigid
Mean annual soil temperature: -4 to -2 degrees C. (25 to 28 degrees F)
Thickness of organic material: 0 to 17 cm (0 to 7 in)
Thickness of epipedon: 27 to 51 cm (11 to 20 in)
Depth to aquic conditions: 34 to 40 cm (13 to 16 in)
Depth to redoximorphic depletions: 34 to 40 cm (13 to 16 in)
Depth to redoximorphic concentrations: 34 to 40 cm (13 to 16 in)
Oi, Oe horizons:
Hue: 7.5YR or 10YR
Value: 2 to 3
Chroma: 1 to 3
Texture: Peat, mucky peat, slightly decomposed organic material
Organic matter: 60 to 90 percent
Reaction class: extremely acid (pH 3.5 to 4.4)
A horizon:
Hue: 10YR or 2.5Y
Value: 2 to 3
Chroma: 1 to 2
Texture: silt loam, gravelly silt loam
Sand: 15 to 30 percent
Silt: 55 to 78 percent
Clay: 5 to 15 percent
Rock fragments: 0 to 22 percent gravels
Organic matter: 4 to 8 percent
Reaction class: moderately acid to slightly acid (pH 5.1 to 6.5)
Bg and C horizon:
Hue: 2.5Y or 5Y
Value: 3 to 5
Chroma: 1 to 2
Texture: loamy sand, sandy loam, sandy clay loam
Sand: 53 to 87 percent
Silt: 0 to 42 percent
Clay: 5 to 22 percent
Rock fragments: 1 to 11 percent gravels
Organic matter: 0.1 to 2 percent
Reaction class: Slightly acid to neutral (pH 6.1 to 7.3)
COMPETING SERIES: These are the
Firth (ID) soils
Firth soils are calcareous.
GEOGRAPHIC SETTING:
Elevation: 400 to 1200 meters (1310 to 3935 feet)
Parent material: organic material over silty loess over sandy and clayey till
Landform: mountain slopes, hillslopes, hills, mountain valleys
Slopes: 15 to 43 percent
Mean annual precipitation: 300 to 1000 mm (12 to 39 in)
Mean annual air temperature: -5 to -1 degrees C. (23 to 30 degrees F)
Frost-free period: 32 to 90 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Ahtell,
Cirquecreek,
Greylingcreek,
Haggardcreek,
Haleycreek, and
Kimballpass soils.
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, has a cambic horizon, do not have a mollic horizon, and occur on saddles and mountain slopes
Greylingcreek soils are excessively drained, do not have a mollic epipedon, and occur in mountain valleys and moraines.
Haggardcreek soils are well drained, has a folistic epipedon, there is bedrock within 2 meters of the soil surface, and occur on hillslopes and mountain slopes.
Haleycreek soils are well drained with a cobbly sandy loam surface texture, do not have a lithic contact, and occur on hillslopes of mountains and river valleys.
Kimballpass soils are well drained and occur on slopes between 20 and 70%.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class: somewhat poorly drained
Saturated Hydraulic Conductivity: high in the Oi and C horizons, moderately high in the A and Bg horizons.
Permeability: moderately rapid in the Oi and C horizons, moderate in the A horizon, moderately slow in the Bg horizon.
Runoff: very high
USE AND VEGETATION:
Use: wildlife habitat, recreation, and subsistence
Native vegetation: bog blueberry, resin birch, moss
DISTRIBUTION AND EXTENT: MLRA 228 Interior Alaska mountains.
Extent: moderate
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: 42 to 117 cm (17 to 46 in)
Mollic epipedon: 17 to 63 cm (7 to 25 in) (A and Bg horizons)
Aquic conditions: 38 to 63 cm (15 to 25 in) (Bg horizon)
Redoximorphic depletions: 38 to 63 cm (15 to 25 in) (Bg horizon)
Redoximorphic concentrations: 38 to 63 cm (15 to 25 in) (Bg horizon)
ADDITIONAL DATA:
User pedon Id: 2023AK261142
National Cooperative Soil Survey
U.S.A.