LOCATION SWAN TX
Established Series
WLM-CLN
02/2026
SWAN SERIES
Depth class: Very deep
Drainage class: Very poorly drained
Flooding frequency and duration: Very frequent, brief
Saturated hydraulic conductivity: Low to moderately low in the surface and moderately high to very high throughout the rest of the profile
Parent material: Fine-loamy alluvium
Slope: 0 to 1 percent
Mean annual air temperature: 22 degrees C (72 degrees F)
Mean annual precipitation: 1067 millimeters (42 inches)
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, calcareous, hyperthermic Typic Endoaquolls
TYPICAL PEDON: Swan mucky peat on a nearly level flood plain at an elevation of 2 meters. (Colors are for moist soil unless otherwise stated.)
Oe--0 to 8 centimeters; dark olive gray (5Y 3/2) mucky peat, olive gray (5Y 4/2) dry; 60 percent unrubbed fiber content, 30 percent rubbed fiber content; H4 von Post humification; massive; soft, very friable; many fine and medium roots; strongly saline; moderately alkaline (pH 8.2); clear smooth boundary. (Oe horizon is 0 to 13 centimeters thick)
Ag--8 to 38 centimeters; very dark gray (N 3/) clay, dark gray (N 4/) dry; weak fine prismatic structure parting to moderate fine angular blocky structure; very hard, firm; few medium and common fine roots; many fine faint black (N 2.5/) iron depletions; 1 percent fine fragments of shells; strongly effervescent (HCl); strongly saline; moderately alkaline (pH 8.2); clear wavy boundary. (Ag horizon is 25 to 43 centimeters thick)
Cg1--38 to 76 centimeters; dark gray (5Y 4/1) sandy clay loam, gray (5Y 5/1) dry; massive; hard, friable; few fine roots; 1 percent fine shell fragments; strongly effervescent (HCl); strongly saline; moderately alkaline (pH 8.2); clear wavy boundary.
Cg2--76 to 122 centimeters; gray (5Y 6/1) sandy loam, light gray (5Y7/1) dry; massive; soft, very friable; few fine roots; 10 percent coarse distinct very dark gray (5Y 3/1) and dark gray (5Y 4/1) iron depletions; 1 percent fine shell fragments; strongly effervescent (HCl); strongly saline; moderately alkaline (pH 8.2); clear wavy boundary.
Cg3--122 to 160 centimeters; light brownish gray (10YR 6/2) loamy sand, light gray (10YR 7/2) dry; single grain; soft, loose; 20 percent coarse prominent gray (5Y 5/1) and 10 percent coarse prominent olive (5Y 5/3) and 1 percent medium prominent grayish green (5G 5/2) iron depletions; 1 percent fine shell fragments; strongly effervescent (HCl); strongly saline; moderately alkaline (pH 8.2); clear wavy boundary.
Cg4--160 to 200 centimeters; olive gray (5Y 5/2) loamy sand, light olive gray (5Y 6/2) dry, single grain; slightly hard, loose; 20 percent faint gray (5Y 5/1) iron depletions; 1 percent fine shell fragments; strongly effervescent (HCl); strongly saline; moderately alkaline (pH 8.2).
TYPE LOCATION: Jackson County, Texas; approximately 8.64 kilometers (5.4 miles) south-southeast from the intersection of FM 234 and FM 616 in Vanderbilt, Texas; and approximately 6.26 kilometers (3.9 miles) northwest of the intersection of Bayside Lane and FM 1593 near Formosa Plastics Corporation plant; USGS quadrangle: Point Comfort, Texas
Latitude: 28.7468719
Longitude: -96.5966949
Datum: WGS84
Coordinate Source: From hand-held GPS
RANGE IN CHARACTERISTICS:
Depth to bedrock: Greater than 200 centimeters
Moisture regime: Aquic
Reaction throughout: Moderately to strongly alkaline (pH 7.9 to 9.0)
Particle-size control section (weighted average): 33 to 108 centimeters
Sand content--65 to 70
Clay content--18 to 35
Oe horizon:
Hue--10YR to 5Y
Value--3 or 4
Chroma--1 or 2
Texture--mucky peat
Von Post humification--H4 to H6
Ag horizon:
Hue--10YR to 5Y or is neutral
Value--2 or 3
Chroma--0 or 2
Texture--sandy clay loam, clay loam, silty clay, clay
Cg horizons:
Hue--10YR to 5Y
Value--4 to 7
Chroma--1 to 2
Texture--sandy loam, loam, clay loam, or sandy clay loam
COMPETING SERIES: There are no other series in this family. Series in similar families include
Placedo and
Surfside series.
Placedo soils: have a fine particle-size control section and have ochric epipedon.
Surfside soils: have a very-fine particle-size control section and a water table that fluctuates throughout the year.
GEOGRAPHIC SETTING:
Parent material: Fine-loamy alluvium
Landscape: Coastal plains
Landform: Flood plains
Slope: 0 to 1 percent
Mean annual precipitation: 812 to 1194 millimeters (32 to 47 inches)
Mean annual air temperature: 21 to 22 degrees C (70 to 72 degrees F)
Frost-free period: 330 to 365 days
Elevation: 0 to 3 meters
GEOGRAPHICALLY ASSOCIATED SOILS:
These are the
Aransas,
Navidad, and
Placedo (mentioned above) series.
Aransas soils: are on flood plains, have slickensides, and a fine smectitic particle-size control section.
Navidad soils: are on flood plains, on slightly higher landscape positions, and have thick mollic epipedons.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class: Very poorly drained
Saturated hydraulic conductivity: Low to moderately low in the surface, and moderately high to very high throughout the rest of the profile
Flooding frequency and duration: Very frequent, brief
Seasonal water table: 0 centimeters
Surface runoff: Negligible
USE AND VEGETATION:
Major use: Wildlife habitat
Vegetation: Bushy seaside tansy, chairmaker's bulrush, saltgrass, saltmeadow cordgrass, seashore paspalum, sturdy bulrush
Ecological Site: R150BY550TX-Northern Salt Marsh
DISTRIBUTION AND EXTENT:
General Area: On mainland marshes near bays along the central coast of Texas
Land Resource Region: T-Atlantic and Gulf Coast Lowland Forest and Crop Region
MLRA(s): 150B-Gulf Coast Saline Prairies
Extent: Small
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Special Projects Office
SERIES ESTABLISHED: Jackson County, Texas, 1986
REMARKS:
Classification changed from Typic Haplaquolls to Typic Endoaquolls on 11/2000 based on typifying pedon description.
Typical pedon taxonomic features:
Aquic conditions: 0 to 200 centimeters
Mollic epipedon: 8 to 38 centimeters
Redox depletions: 8 to 200 centimeters
Reduced matrix: 8 to 200 centimeters
Taxonomic version: Keys to Soil Taxonomy, 13th edition (2022)
ADDITIONAL DATA:
OSD User Pedon ID: S1997TX239120
________________________________________
National Cooperative Soil Survey
U.S.A.