LOCATION HARAHAN LAEstablished Series
TAXONOMIC CLASS: Very-fine, smectitic, nonacid, hyperthermic Vertic Endoaquepts
TYPICAL PEDON: Harahan clay on a drained backswamp. (Colors are for moist soil.)
Ap--0 to 4 inches; very dark gray (10YR 3/1) clay; moderate, medium subangular blocky structure; firm; few clam shells; few medium faint dark yellowish brown (10YR 4/4) masses of iron accumulation; slightly acid; abrupt smooth boundary. (3 to 12 inches thick)
Bg1--4 to 13 inches; dark gray (10YR 4/1) clay; weak coarse subangular blocky structure; firm; patchy reddish brown iron stains on faces of peds; common shiny pressure faces; few fine distinct dark yellowish brown (10YR 4/4) masses of iron accumulation; medium acid; clear wavy boundary.
Bg2--13 to 20 inches; very dark gray (10YR 3/1) clay; weak medium subangular blocky structure parting to moderate fine subangular blocky; firm; common shiny pressure faces on surfaces of peds; few fine distinct dark yellowish brown (10YR 4/4) masses of iron accumulation; strongly acid; abrupt wavy boundary (combined thickness of the Bg horizon is 8 to 36 inches).
Ab--20 to 32 inches; black (10YR 2/1) clay; moderate medium subangular blocky structure; firm; few fine roots, few fragments of wood; slightly acid; abrupt wavy boundary. (0 to 13 inches thick)
Cg1--32 to 65 inches; gray (5Y 5/1) clay; massive; flows easily between fingers when squeezed leaving a small residue in hand; few fragments of wood; moderately alkaline; abrupt smooth boundary. (15 to 35 inches thick)
Cg2--65 to 70 inches; dark gray (5Y 4/1) clay; massive; flows easily between fingers when squeezed leaving hand empty; moderately alkaline; abrupt smooth boundary. (0 to 20 inches thick)
Cg3--70 to 75 inches; dark gray (5Y 4/1) clay; massive; flows with difficulty between fingers when squeezed leaving medium residue in hand; few fragments of wood; moderately alkaline.
TYPE LOCATION: Jefferson Parish, Louisiana, in Gretna; 1,300 feet west of Belle Chasse Highway; 200 feet south of Gretna Boulevard; on west side of Gould Fire Company No. 2; 3,100 feet south of northeast corner, sec. 43, T. 14 S., R. 24 E.
RANGE IN CHARACTERISTICS: Thickness of the solum and depth to layers with n value greater than 0.7 ranges from 20 to 40 inches. The reaction of the Ap and Bg horizons ranges from strongly acid to slightly alkaline. The Cg horizon ranges from neutral to moderately alkaline.
The Ap horizon has hue of 10YR, value of 2 to 4, and chroma of 0 to 2. It is clay, mucky clay, or silty clay loam.
Some pedons have a thin Oa horizon on the surface with texture of muck. Other pedons have an Oab horizon, 2 to 7 inches thick, immediately below the Ap horizon. The Oa and Oab horizons have the same range in color as the Ap horizon.
The Bg horizon has hue of 10YR, 2.5Y, 5Y, 5GY, or 5BG; value of 3 to 5; and chroma of 0 to 2. Iron accumulations are in shades of brown. It is clay with or without thin layers or lenses of silty clay.
The Ab horizon, where present, has hue of 10YR, value of 2 to 4, and chroma of 0 to 2. It is clay, silty clay or mucky clay.
The Cg horizon has hue of 10YR, 5Y, 2.5Y, 5BG, 5GY, or 5G; value of 2 to 6; and chroma of 0 to 2. It is clay, silty clay, or mucky clay. In some pedons, the Cg horizon is silty clay loam below a depth of 40 inches.
COMPETING SERIES: The Fausse series in the same family. Fausse soils have a thicker solum with n-value less than 0.7 in the lower part.
GEOGRAPHIC SETTING: Harahan soils are in artificially drained backswamp positions on the flood plain of the lower Mississippi River and its distributaries. They formed from fluid, alluvial clays that were artificially altered by man to become firm and form a solum in the upper 20 to 40 inches. Elevations are about sea level to 1 or 2 feet below sea level. Slope is less than 0.5 percent. Near the type location the average annual rainfall is about 65 inches and the mean annual temperature is about 67 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Fausse series, and Barbary, Gentilly, Scatlake, Schriever, and Thibaut soils. Barbary soils are in undrained backswamps and have n-value more than 0.7 throughout. Gentilly and Scatlake soils are in undrained freshwater to saline marshes, have a histic epipedon, and have n-value more than 0.7 throughout the upper 20 to or more inches. Schriever and Thibaut soils have thicker sola and have n-value less than 0.7 in all layers to 60 or more inches deep.
DRAINAGE AND PERMEABILITY: Harahan soils are poorly drained; runoff is slow and permeability is very slow. The water table is 12 to 36 inches below the surface most of the year. Harahan soils are protected from flooding and the water table is controled by a system of levees and pumps.
USE AND VEGETATION: Used mainly for urban land or recreation. The native vegetation was bottomland hardwoods.
DISTRIBUTION AND EXTENT: On backswamp positions on the lower Mississippi River and its distributaries near the Gulf Coast. This soil is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
MLRA: Southern Mississippi Valley Alluvium (131)
SERIES ESTABLISHED: Jefferson Parish, Louisiana, May 1981.
REMARKS: Harahan soils were formerly mapped and published in special reports as "Sharkey clay, miry subsoil variant".
Diagnostic horizons and features recognized in this pedon include:
Ochric epipedon................0 to 4 inches (Ap horizon)
Cambic horizon.................4.to 25 inches (Bg horizons)
N-value > 0.7..................32 to 75 inches (Cg horizons)