LOCATION WAHI                    HI

Established Series
Rev. KH-RTG
06/2012

WAHI SERIES

The Wahi series consists of deep, somewhat excessively drained soils formed in basic volcanic ash deposited over basic `a`a lava. Slopes range from 2 to 20 percent. The mean annual rainfall is about 1,473 millimeters (58 inches), and the mean annual air temperature is about 13 degrees C (55 degrees F).

TAXONOMIC CLASS: Medial-skeletal, amorphic, isomesic Typic Hapludands

TYPICAL PEDON: Wahi extremely cobbly medial loam, 13 percent slope under scattered ohia trees and shrubs at an elevation of 2,134 meters (7,000 feet). The surface of the soil is partially covered by fragmental `a`a lava (5 percent boulders, 10 percent stones, 45 percent cobbles and 20 percent gravel). (Colors are for moist soil unless otherwise noted. When described on 7/10/98 the soil was slightly moist throughout. The soil temperature was 12 degrees C (54 degrees F) at a depth of 10 centimeters (4 inches). All textures are "apparent field textures". pH was measured using organic dyes.)

3C1/A1--0 to 5 centimeters (0 to 2 inches); very dark brown (7.5YR 2.5/2) extremely cobbly medial loam, dark brown (10YR 3/3) dry; moderate coarse platy structure; slightly hard, friable, nonsticky and nonplastic; common very fine and fine roots; many very fine and fine interstitial pores; 70 percent `a`a lava (5 percent boulders, 10 percent stones, 45 percent cobbles, and 20 percent gravel); strongly acid (pH 5.2); the 3C part of this horizon consists of unconsolidated pahoehoe lava fragments of variable size; clear wavy boundary. (5 to 10 centimeters (2 to 4 inches) thick)

3C2/A2--5 to 13 centimeters (2 to 5 inches); dark reddish brown (5YR 2.5/2) extremely cobbly medial loam, dark brown (7.5YR 3/2) dry; weak coarse subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; many very fine and fine interstitial pores; 80 percent `a`a lava (10 percent stones, 60 percent cobbles, and 10 percent gravel); moderately acid (pH 6.0); the 3C part of this horizon consists of unconsolidated pahoehoe lava fragments of variable size; clear wavy boundary. (5 to 13 centimeters (2 to 5 inches) thick)

3C3/2A--13 to 25 centimeters (5 to 10 inches); very dark brown (7.5YR 2.5/2) extremely cobbly medial loam, dark brown (7.5YR 3/2) dry; weak medium subangular blocky structure parting to moderate fine and medium granular; slightly hard, friable, nonsticky and nonplastic; many very fine, fine, and medium, and common coarse roots; many very fine and fine interstitial pores; 80 percent `a`a lava (10 percent stones, 60 percent cobbles, and 10 percent gravel); moderately acid (pH 6.0); the 3C part of this horizon consists of unconsolidated pahoehoe lava fragments of variable size; clear irregular boundary. (0 to 13 centimeters (0 to 5 inches) thick)

3C4/2Bw1--25 to 30 centimeters (10 to 12 inches); very dark brown (7.5YR 2.5/2) extremely cobbly medial loam, strong brown (7.5YR 4/6) dry; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine, fine and few medium roots; many very fine and fine interstitial pores; 65 percent `a`a lava (50 percent cobbles and 15 percent gravel); slightly acid (pH 6.2); the 3C part of this horizon consists of unconsolidated pahoehoe lava fragments of variable size; abrupt wavy boundary.

3C5/2Bw2--30 to 36 centimeters (12 to 14 inches); very dark brown (7.5YR 2.5/3) extremely cobbly medial loam, strong brown (7.5YR 4/6) dry; moderate fine and medium platy structure; slightly hard, friable, nonsticky and nonplastic; common very fine, fine, and medium and few coarse roots; many very fine and fine interstitial pores; 65 percent `a`a lava (55 percent cobbles and 10 percent gravel); slightly acid (pH 6.2); the 3C part of this horizon consists of unconsolidated pahoehoe lava fragments of variable size; clear wavy boundary. (combined thickness of 3C/2Bw horizons 0 to 15 (0 to 6 inches))

3C6--36 to 152 centimeters (14 to 60 inches); very dark brown (7.5YR 2.5/2) extremely stony medial loam, dark brown (7.5YR 3/3) dry; fines decrease with depth, single grain; soft, very friable, nonsticky and nonplastic; common very fine, fine, and medium, and few coarse roots; many fine and medium and few coarse interstitial pores; 80 percent `a`a lava (15 percent boulders, 20 percent stones, 40 percent cobbles, and 5 percent gravel); 5 percent voids; slightly acid (pH 6.4).

TYPE LOCATION: Hawaii Volcanoes National Park; from State Hwy. 11 drive 11 miles north on Mauna Loa Strip Road to the end; take Mauna Loa Trail to the 7,000-feet elevation sign; walk on a 165-degree magnetic heading for 30 meters (96 feet) to type location; Puu Ulaula Quadrangle; lat. 19 degrees 30 seconds 20.72 minutes N. and long. 155 degrees 23 minutes 33.02 seconds W. (Old Hawaiian Datum measured by GPS/PLGR, 420 feet).

RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 11 to 13 degrees C (52 to 55 degrees F).
Rock fragments: 65 to 90 percent on both soil surface and in the control section.

A horizon
Hue: 7.5YR or 10YR.
Texture: Medial loam or medial silt loam.
Structure: Platy, granular, or subangular blocky.

B horizon
Hue: 5YR to 10YR.
Chroma: 2 to 4 moist.
Structure: Subangular blocky or platy.

C horizon
Rock fragments: 65 to 90 percent.
Voids: 5 to 10 percent.

COMPETING SERIES: This is the Keamoku series. Keamoku soils have rock fragments below depths 10 to 50 centimeters and have mean annual soil temperature 13 to 15 degrees C (55 to 59 degrees F). Kulalio soils are similar. Kulalio soils are black in the upper part of the profile and have sandy texture at depths below 27 centimeters (11 inches).

GEOGRAPHIC SETTING: Wahi soils are on Mauna Loa `a`a flows less than 750 years old at elevations of 2,042 to 2,320 meters (6,700 to 7,500 feet). General slopes range from 2 to 20 percent, but short complex micro-slopes range from 8 to 35 percent. The mean annual rainfall is 1,270 to 1,524 millimeters (50 to 60 inches), with about 75 percent of the rainfall occurring between November and May. The mean annual pan evaporation is 1,270 to 1,524 millimeters (50 to 60 inches). The mean annual air temperature is 10 to 14 degrees C (50 to 57 degrees F).

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kaholimo, Puiwa, and the similar Kulalio soils. Kaholimo and Puiwa soils are non-skeletal and overlie pahoehoe lava.

DRAINAGE AND PERMEABILITY: Somewhat excessively drained; low runoff; rapid permeability.

USE AND VEGETATION: These soils are used for National Park Service land and pasture. Vegetation is aalii (Dodonaea viscosa), kukaenene (Coprosma ernodeoides), ohelo (Vaccinium reticulatum), ohia lehua (Metrosideros polymorpha), pukiawe (Styphelia tameiameiae), uki (Machaerina angustifolia), naenae (Dubautia ciliolata), and scattered grasses.

DISTRIBUTION AND EXTENT: These soils occur within Hawaii Volcanoes National Park and surrounding ranches; MLRA 160. The series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.

SERIES ESTABLISHED: Island of Hawaii, Hawaii County, Hawaii, 2012 Proposed 1998. The name is from Puu Wahi.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Andic soil properties - 0 to 152 centimeters (60 inches).
Umbric epipedon - 0 to 36 centimeters (14 inches).
Soil temperature - mean summer and mean winter soil temperatures differ by less than 6 degrees C (iso temperature regime).
Soil moisture - not dry in some or all parts for 90 days or more in most years (udic moisture regime).

Edit Log: 12/03 KH. Added "medial" modifier to textures. Added Keamoku to Competing Series.

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National Cooperative Soil Survey
U.S.A.