LOCATION KWATAHEIN AK
Established Series
Rev. EJK-JPM
05/2022
KWATAHEIN SERIES
The Kwatahein series consists of very deep, well drained soils developed in residuum from partially consolidated, soft siltstone or mudstone bedrock. Kwatahein soils occur on infrequently dissected smooth hillslopes. Slopes range from 5 to 95 percent. Mean annual air temperature is about 41 degrees F., and the mean annual precipitation is about 110 inches. Elevation ranges from near sea level to 2000 feet.
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive Typic Haplocryods
TYPICAL PEDON: Kwatahein silt loam - on a south facing slope of 45 percent under forest vegetation. (All colors are for moist soil.)
Oi--12 to 10 inches; dark reddish brown (5YR 2.5/2) peat consisting of leaves and twigs. (0 to 3 inches thick)
Oe--10 to 3 inches; black (5YR 2.5/1) mucky peat consisting of partially decomposed forest litter; 15 percent rubbed fiber content; many medium and coarse and common fine roots; very strongly acid (pH 4.5 Truog); clear smooth boundary. (0 to 10 inches thick)
Oa--3 to 0 inches; black (5YR 2.5/1) muck consisting of decomposed forest litter; 5 percent rubbed fiber content; common fine and common medium roots; very strongly acid (pH 4.5 Truog); abrupt wavy boundary. (0 to 4 inches thick)
E --0 to 1 inch; brown (7.5YR 5/2) silt loam; moderate fine subangular blocky structure; friable; slightly sticky and slightly plastic; 2 percent gravel; few fine roots; very strongly acid (pH 4.5 Truog); abrupt irregular boundary. (1 to 3 inches thick)
Bhs--1 to 7 inches; dark reddish brown (5YR 2.5/2) gravelly silt loam; moderate fine subangular blocky structure; very friable, slightly sticky and slightly plastic; 20 percent gravel; very strongly acid (pH 5.0 Truog); clear wavy boundary. (3 to 6 inches thick)
Bs--7 to 15 inches; yellowish red (5YR 4/6) loam; weak fine subangular blocky structure; very friable, slightly sticky and slightly plastic; 5 percent gravel; strongly acid (pH 5.5 Truog); clear wavy boundary. (4 to 10 inches thick)
C--15 to 60 inches; strong brown (7.5YR 5/8) gravelly loam; massive; friable; slightly sticky and slightly plastic; residuum from siltstone; 30 percent gravel; moderately acid (pH 6.0 Truog)
TYPE LOCATION: Security Bay Area on Kuiu Island, Alaska; SW 1/4, Section 34, T.58S., R71E., Copper River Meridian.
RANGE IN CHARACTERISTICS: Mean annual soil temperature ranges from 38 to 42 degrees F. Weighted average particle size of the control section has less than 18 percent clay and more than 15 percent fine sand or coarser. Coarse fragments are typically sharp angular gravel size fragments of siltstone or mudstone. Coarse fragment content typically increases with depth, but the weighted average in the control section ranges from 5 to 35 percent. Reaction ranges from extremely acid to strongly acid in the solum and is moderately acid or slightly acid in the C horizon.
The combined thickness of the O horizon ranges from 4 to 13 inches.
The E horizon has hue of 5YR or 7.5YR, value from 4 to 6, and chroma from 1 to 3. Texture is loam or silt loam.
The Bhs horizon has hue of 5YR or 7.5YR, value and chroma of 2 or 3. Texture is loam, silt loam or sandy loam.
The Bs horizon has hue of 5YR or 7.5YR, value from 3 to 5, and chroma from 4 to 6. Texture is loam, silt loam or sandy loam.
The C horizon has value from 4 to 6, and chroma from 2 to 8. Texture typically is loam or gravelly loam but ranges to include silt loam and sandy loam. Consistence is friable or firm.
COMPETING SERIES: These are the
Barlow,
Flat Horn,
Hartnit, Lorraine,
Oso,
Stainky,
Timberly and
Yohn series. Barlow, Stainky and Yohn soils have very gravelly till substratums. Flat Horn and Lorraine soils have control sections dominated by amorphous material from ash. Hartnit and Oso soils have bedrock at 20 to 40 inches. Timberly soils have A horizons.
GEOGRAPHIC SETTING: The Kwatahein soils occur on long smooth hillslopes. The soils formed in soft saprolite from mudstone or siltstone. Climate is humid maritime with mean annual precipitation ranging from 90 to 120 inches. Mean annual temperature is 41 degrees F. Slopes range from 5 to 95 percent. Elevation ranges from near sea level to 2000 feet.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Kupreanof,
Mitkof and
Tolstoi soils. Kupreanof soils are on lower slope concave positions and are developed in colluvium or glacial till. Mitkof soils are on concave slopes and are somewhat poorly drained. Tolstoi soils are on short convex slopes and are shallow soils over bedrock.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability; slow to rapid runoff.
USE AND VEGETATION: The Kwatahein soils are used for timber production, wildlife habitat and watershed protection. The overstory in climax plant communities is dominated by Western Hemlock with lesser amounts of Sitka Spruce. The understory is dominated by blueberry, bunchberry, goldthread, twayblade, five-leaf bramble, twisted stalk and shield fern.
DISTRIBUTION AND EXTENT: Southeastern Alaska. The series is moderately extensive.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA
SERIES ESTABLISHED: Stikine Area, Alaska 1993.
REMARKS: Diagnostic horizons and features recognized in this soil are: an albic horizon from 0 to 1 inch; a spodic horizon from 1 to 15 inches; assumed cryic temperature regime; weighted average particle size of coarse-loamy from 10 to 40 inches.
National Cooperative Soil Survey
U.S.A.