LOCATION OTTAWAY AK
Established Series
SDB
08/2025
OTTAWAY SERIES
Depth class: moderately deep to permafrost
Drainage class: moderately well drained
Parent material: organic material over sandy and silty eolian sands over gravelly colluvium and/or sandy and silty slope alluvium
Landscape: mountains
Landform: hills and mountain slopes
Slope: 25 to 70 percent
Aspect: counterclockwise to 300 degrees and clockwise to 40 degrees
Mean annual precipitation: about 450 mm (18 in)
Mean annual air temperature: about -2 degrees C (28 F)
Frost-free period: 36 to 103 days
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, nonacid, subgelic Typic Mollorthels
TYPICAL PEDON: Ottaway fine sandy loam in a black spruce community on north facing linear, linear, backslope on a slope of 60 percent at an elevation of 559m (1835 ft).
Oi--0 to 13 cm (0 to 5 in); slightly decomposed plant material, dark brown (7.5YR 3/2) moist; many very fine, many fine, and common medium roots throughout; noneffervescent; slightly alkaline (pH 7.4); clear smooth boundary (12 to 17 cm, 5 to 7 in)
AO--13 to 19 cm (5 to 7 in); slightly decomposed plant material, highly organic fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, very friable, nonsticky, nonplastic; nonsmeary; many very fine, many fine, and many medium roots throughout; very fine and fine pores; noneffervescent; slightly alkaline (pH 7.8); abrupt smooth boundary (5 to 13 cm, 2 to 5 in)
A--19 to 40 cm (7 to 16 in); highly organic very fine sandy loam, very dark brown (10YR 2/2) moist; moderate medium subangular blocky structure; soft, very friable, nonsticky, nonplastic; nonsmeary; many very fine, many fine, and many medium roots throughout; very fine and fine pores; noneffervescent; slightly alkaline (pH 7.6); very abrupt irregular boundary (18 to 22 cm, 7 to 9 in)
C--40 to 55 cm (16 to 22 in); stones, very dark brown (10YR 2/2) moist; slightly hard, friable; nonsmeary; 10 percent cobbles and 90 percent stones by volume; noneffervescent; slightly alkaline (pH 7.6); clear irregular boundary. (8 to 20 cm, 3 to 8 in)
A/Cf--55 to 150 cm (22 to 59 in); extremely stony very fine sandy loam, very dark grayish brown (10YR 3/2) moist; massive; very rigid, very rigid, noncoherent, nonsticky, nonplastic; nonsmeary; 10 percent cobbles and 70 percent stones by volume; noneffervescent; neutral (pH 7.1). (78 to 95 cm,31 to 37 in)
TYPE LOCATION: North Copper River Soil Survey Area, Alaska; latitude 61.63144, longitude -144.64792, UTM 6835375.05 north and UTM 624662.19 east, zone 6, Datum WGS84.
RANGE IN CHARACTERISTICS:
Soil moisture regime: udic
Soil temperature regime: gelic
Mean annual soil temperature: -4 to 1 degrees C. (25 to 34 degrees F)
Thickness of organic material: 12 to 17 cm (5 to 7 in)
Thickness of mollic epipedon: 23 to 35 cm (9 to 14 in)
Depth to permafrost: 43 to 72 cm (17 to 28 in)
Oi, 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: neutral to slightly alkaline (pH 7.0 to 7.8)
A horizons:
Hue: 7.5YR or 10YR
Value: 2 to 3
Chroma: 1 to 2
Texture: highly organic fine sandy loam, highly organic sandy loam, highly organic very fine sandy loam.
Sand: 50 to 69 percent
Silt: 24 to 45 percent
Clay: 1 to 14 percent
Rock fragments: 0 percent
Organic matter: 3 to 10 percent
Reaction class: neutral to moderately alkaline (pH 7.0 to 8.2)
C, A/C horizons:
Hue: 10YR or 2.5Y
Value: 2 to 3
Chroma: 2 to 3
Texture: fragmental, extremely stony sandy loam, extremely stoney very fine sandy loam.
Sand: 54 to 69 percent
Silt: 24 to 44 percent
Clay: 2 to 14 percent
Rock fragments: 61 to 100 percent
Cobbles: 5 to 16 percent
Stones: 55 to 90 percent
Organic matter: 0 to 2 percent
Reaction class: neutral to slightly alkaline (pH 6.6 to 7.8)
COMPETING SERIES: there are no competing series.
GEOGRAPHIC SETTING:
Elevation: 300 to 1300 meters (985 to 4265 ft)
Parent material: organic material over sandy and silty eolian sands over gravelly colluvium and/or sandy and silty slope alluvium
Landform: hills and mountain slopes
Slopes: 25 to 70 percent
Mean annual precipitation: 300 to 800 mm (12 to 31 in)
Mean annual air temperature: -4 to 1 degrees C. (25 to 34 degrees F)
Frost-free period: 36 to 103 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ride, Rocklake, Saintelias, Stibnite,
Taral, and Townlake soils.
Ride soils are somewhat excessively drained, lack permafrost or a mollic epipedon, and occur on mountain slopes and hillslopes.
Rocklake soils are shallow to bedrock, lack permafrost, and occur on ridge lines and escarpments.
Saintelias soils are poorly drained, have a histic epipedon, form over lacustrine sediments, and occur on terraces and in river valleys atop
Stibnite soils are well drained, lack permafrost, have a cambic horizon, and occur in till plains, mountains, kames and kettles.
Taral soils are well drained, lack permafrost, have a deep (>40 cm, 16 in thick) mollic epipedon, and occur on mountain and hill slopes greater than 25 percent.
Townlake soils have a folistic epipedon, a cryoturbated horizon, and occurs on hills, mountain slopes, and river valleys.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class: moderately well drained
Saturated Hydraulic Conductivity: very high in the Oi and C horizon, high in the A/O and A horizons, low in the A/Cf horizon.
Permeability: very rapid in the Oi and C horizon, moderately rapid in the A/O and A horizons, very slow in the A/Cf horizon.
Runoff: high
USE AND VEGETATION:
Use: wildlife habitat, recreation, and subsistence
Native vegetation: black spruce, alder, 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: 38 to 113 cm (15 to 44 in)
Mollic epipedon: 13 to 40 cm (5 to 14 in) (AO and A horizon)
Permafrost: 55 to 150 cm (22 to 59 in) (A/Cf horizon)
ADDITIONAL DATA:
User pedon Id: 2022AK261040
National Cooperative Soil Survey
U.S.A.