LOCATION SKOOKUMCREEK WA
Tentative Series
IRD. MGR/MPR
01/2025
SKOOKUMCREEK SERIES
Landscape--mountains
Landform--colluvial aprons and glacial valley walls
Slope--15 to 100 percent
Parent material--colluvium from metasedimentary rock
Mean annual precipitation--about 2500 mm
Mean annual air temperature--about 6 degrees C
Depth class--very deep
Drainage class--well drained
Soil moisture regime--udic
Soil temperature regime--frigid
Soil moisture subclass--typic
TAXONOMIC CLASS: Loamy-skeletal, isotic, frigid Andic Dystrudepts
TYPICAL PEDON: Skookumcreek very gravelly loam on an east facing, forested glacial valley wall with a slope of 30 percent and an elevation of 560 m. (The soil was moist throughout when described.)
Oi--0 to 3 cm; slightly decomposed organic material; abrupt wavy boundary
A--3 to 13 cm; brown (7.5YR 4/4) dry, dark brown (7.5YR 3/4), gravelly loam; moderate fine granular structure; soft, very friable, slightly sticky, slightly plastic; weakly smeary; many very fine, fine, medium, and coarse and common very coarse roots; many fine irregular pores; 20 percent gravel; very strongly acid (pH 4.6); clear smooth boundary
Bw1--13 to 34 cm; very dark grayish brown (10YR 3/2) dry, very dark brown (10YR 2/2), extremely gravelly loam; weak very fine subangular blocky structure; soft, very friable, slightly sticky, slightly plastic; weakly smeary; few very fine, coarse, and very coarse and common fine and medium roots; many very fine irregular and common fine interstitial pores; 40 percent gravel, 15 percent cobbles, 10 percent stones; very strongly acid (pH 4.7); clear wavy boundary
Bw2--34 to 66 cm; dark yellowish brown (10YR 4/4) dry, dark brown (10YR 3/3), very gravelly loam; weak very fine subangular blocky structure; soft, very friable, slightly sticky, slightly plastic; weakly smeary; many very fine, few medium, and common fine roots; many very fine irregular and few fine interstitial pores; 45 percent gravel, 5 percent cobbles, and 5 percent stones; very strongly acid (pH 4.8); clear wavy boundary
Bw3--66 to 150 cm; dark yellowish brown (10YR 4/4) dry, dark brown (10YR 3/3) moist, extremely gravelly loam; weak very fine subangular blocky structure; soft, very friable, slightly sticky, slightly plastic; common very fine roots; many very fine irregular and common fine interstitial pores; 40 percent gravel, 25 percent cobbles, and 10 percent stones; very strongly acid (pH 5.0)
TYPE LOCATION: Olympic National Park, Mason County, Washington, North fork of Skokomish River Trail, approximately one mile south of Nine Stream Camp.
Latitude--47.604486
Longitude-- -123.352036
Datum--WGS84
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--4 to 7 degrees C
Mean summer soil temperature--6 to 10 degrees C
Particle-size control section
*Clay content--7 to 15 percent
*Total rock fragment content--45 to 75 percent
*Gravel content--35 to 75 percent
*Cobble content--5 to 30 percent
*Stone content--0 to 15 percent
Oi or Oe horizon
Thickness--0-5 cm
A horizon
Hue--10YR or 7.5YR
Value--2 or 3 moist
Chroma--1 to 4 moist
Fine-earth texture--silt loam, loam, sandy loam
Clay content--8 to 17 percent
Total rock fragment content--15 to 35 percent
Gravel content--15 to 35 percent
Cobble content--0 to 10 percent
Reaction--4.5 to 5.5
Thickness--8 to 20 cm
Bw horizons
Hue--10YR or 2.5Y
Value--3 or 4 moist, 4 or 5 dry
Chroma--2 to 4, moist or dry
Fine-earth texture--loam, sandy loam
Clay content--8 to 17 percent
Total rock fragment content--45 to 75 percent
Gravel content--35 to 65 percent
Cobble content--5 to 30 percent
Stone content--0 to 15 percent
Reaction--4.5 to 5.5
Combined Thickness--130 to 150 cm
COMPETING SERIES:
Chintimini,
Hoffstadt,
Sarazan--have a lithic contact within 100 to 150 cm of the soil surface
Tricouni--has an albic horizon, and E and Bw horizons containing greater than 5 percent volcanic glass
GEOGRAPHIC SETTING:
Elevation--500 to 1100 m
Climate--warm, dry summers; cool, wet winters
Mean annual precipitation--2000 to 3000 mm
Mean annual air temperature--7 to 11 degrees C
Frost-free period--90 to 150 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Bonjonpass--contains albic and spodic horizons; occurs on lower slope areas of similar landforms
Charlialakes--moderately deep; ridges and bedrock knobs on similar landforms
Lapoetcreek--coarse loamy particle size class; alluvial terraces adjacent to similar landforms
Mountscott--aquic conditions within 50 cm of the mineral soil surface; depressions on similar landforms
Mountclaywood-- aquic conditions within 25 cm of the mineral soil surface; depressions on similar landforms
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--well drained
Saturation in normal years--none
Flooding--none
Ponding--none
Saturated hydraulic conductivity (Ksat)--high or very high throughout
USE AND VEGETATION:
Use--wildlife habitat and recreation
Potential natural vegetation--Pacific silver fir, western hemlock, Douglas-fir, oval-leaf huckleberry, red huckleberry, Cascade Oregongrape, western swordfern, deerfoot vanillaleaf, twinflower
DISTRIBUTION AND EXTENT: Olympic Mountains, Washington; MLRA 1; large extent
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Olympic National Park, Mason County, Washington 2023; name from Skookumcreek in Olympic National Park
REMARKS:
Diagnostic horizons and other features in this pedon:
*Particle size control section-- zone from 25 to 100 cm
*Ochric epipedon
*Cambic Horizon--zone from 13 to 66 cm
*Andic subgroup properties-zone from 3 to 66 cm; AO extractable Al + Fe is 1 to 2 percent and Db is 0.9 to 1.0
National Cooperative Soil Survey
U.S.A.