LOCATION ALTITUDE                CO

Established Series
PRR-KLS-EED
03/2026

ALTITUDE SERIES

Depth class: Deep or very deep
Drainage class: Well drained
Saturated hydraulic conductivity: Moderately high (0.4 to 3.6 cm/hr)
Parent material: Thick loamy-skeletal human-transported material over alluvium
Geomorphic location: Fills and other leveled areas on stream terraces
Slope range: 0 to 25 percent
Mean annual temperature: 11 degrees C
Mean annual precipitation: 405 millimeters

TAXONOMIC CLASS: Loamy-skeletal, spolic, mixed, superactive, calcareous, mesic Anthroportic Ustorthents

TYPICAL PEDON: Altitude clay loam, 3 percent slope on a filled stream terrace under cultivated grass in a park, at an elevation of 1,592 meters. (Colors are for dry soil unless otherwise noted.)

^A--0 to 14 centimeters; grayish brown (10YR 5/2) clay loam, very dark grayish brown (10YR 3/2) moist; moderate fine granular structure, slightly hard, firm, moderately sticky, moderately plastic; 10 percent subrounded fine and medium gravel; noneffervescent; neutral (pH 7.0); clear wavy boundary (5 to 25 centimeters thick)

^C--14 to 70 centimeters; brown (7.5YR 5/4) very gravelly sandy loam, brown (7.5YR 4/4) moist; massive, slightly hard, friable, slightly sticky, slightly plastic; 50 percent subrounded fine and medium gravel; finely disseminated free carbonates in the soil matrix; slightly effervescent; slightly alkaline (pH 7.6); clear wavy boundary

^Cu1--70 to 111 centimeters; brown (7.5YR 5/3) gravelly-artifactual sandy loam, dark brown (7.5YR 3/3) moist; massive; slightly hard, friable, slightly sticky, slightly plastic; 11 percent subrounded fine and medium gravel; 5 percent gravel sized artifacts; finely disseminated free carbonates in the soil matrix; strongly effervescent; moderately alkaline (pH 8.1); clear wavy boundary

^Cu2--111 to 145 centimeters; variegated 50 percent brown (10YR 5/3) and 50 percent brownish yellow (10YR 6/6), clay loam, variegated 50 percent brown (10YR 4/3) and 50 percent dark grayish brown (10YR 4/2) moist; 10 percent dark gray (2.5Y 4/1) and 15 percent dark brown (7.5YR 3/4) mottles; massive, moderately hard, firm, moderately sticky, moderately plastic; 5 percent subrounded fine and medium gravel; 2 percent artifacts of paper; finely disseminated free carbonates in the soil matrix; very slightly effervescent; slightly alkaline (pH 7.6); abrupt smooth boundary (Combined thickness of the ^C horizons are 55 centimeters or more thick)

2C--145 to 200 centimeters; brown (10YR 5/3), very gravelly coarse sand, dark yellowish brown (10YR 3/4) moist; single grain; loose, nonsticky, nonplastic; 55 percent subrounded fine and medium gravel; finely disseminated free carbonates throughout the matrix; very slightly effervescent; slightly alkaline (pH 7.8)

TYPE LOCATION:
Denver County, Colorado; located in the west-central part of Fishback Park

USGS Quadrangle: Arvada
Latitude: 39.7526639
Longitude: -105.0123028
Datum: WGS84
Coordinate source: Hand-held GPS

RANGE IN CHARACTERISTICS:
Thickness of human-transported material: 70 to greater than 200 centimeters
Depth to bedrock: 100 to greater than 150 centimeters
Depth to seasonal highwater table: 150 to greater than 200 centimeters
Soil reaction: Neutral to slightly alkaline (pH 7.0 to 8.0)
Depth to free carbonates: 10 to 25 centimeters
Particle-size control section (weighted average):
Clay content--10 to 35 percent
Sand content--30 to 75 percent
Rock fragment content--35 to 65 percent
Artifact content--less than 10 percent, by volume; some individual horizons have more than 10 percent artifacts.

^A(u) horizons:
Hue--10YR
Value--3 to 5 dry; 1 to 4 moist
Chroma--2 to 5 dry; 2 to 4 moist
Texture (less than 2 mm fraction)--Clay loam, sandy clay loam, loam
Clay content--20 to 30 percent
Rock fragment content--0 to 10 percent gravel
Artifact content--0 to 10 percent
Calcium carbonate equivalent--0 to 3 percent
Reaction--Neutral to moderately alkaline (pH 7.0 to 8.2)

^C(u) horizons:
Hue--7.5YR to 10YR
Value--3 to 6 dry or moistChroma--2 to 6 dry or moist
Texture (less than 2 mm fraction)--Clay loam, sandy clay loam, sandy loam
Clay content--10 to 25 percent , with some pedons having as little as 5 percent and others as high as 30 percent clay
Rock fragment content--20 to 50 percent gravel
Artifact content--0 to 5 percent
Calcium carbonate equivalent--0 to 14 percent
Reaction--Slightly to moderately alkaline (pH 7.5 to 8.2)

2C horizons (when present):
Hue--10YR
Value--4 or 5 dry; 3 or 4 moist
Chroma--3 or 4 dry or moist
Texture (less than 2 mm fraction)-- Coarse sand, loamy coarse sand, silty clay loam
Clay content--28 to 35 percent, with some pedons having as little as two percent clay
Rock fragment content--0 to 5 percent, with some pedons having up 55 percent gravel
Calcium carbonate equivalent--3 to 5 percent
Reaction--Slightly to moderately alkaline (pH 7.6 to 8.4)

COMPETING SERIES:
There are no competing series; soils in similar families are Elyria, Globeville, and Milehigh soils.

Elyria soils have fine-loamy particle size control sections.
Globeville soils have fine-loamy particle size control sections and are in a nonacid reaction class.
Milehigh soils have coarse-loamy particle size control sections and are in a nonacid reaction class.

GEOGRAPHIC SETTING:
Parent material: Thick loamy-skeletal human-transported material over alluvium
Landform: Fills and other leveled areas on stream terraces
Slope: 0 to 25 percent
Elevation: 1,560 to 1,680 meters
Frost-free period: 135 to 165 days
Mean annual air temperature: 10 to 12 degrees C
Mean annual precipitation: 355 to 430 millimeters
Climate: Cold, dry winters and hot summers with North American monsoon precipitation from July through August. The driest months are December through February.

GEOGRAPHICALLY ASSOCIATED SOILS:
These are the Elyria, Globeville, Milehigh, and Racas soils.

Elyria soils are found on similar landscape positions, as well as on adjacent strath terraces and plains. Elyria soils have fine-loamy particle size control sections, and form in human-transported materials over mixed eolian deposits or alluvium.
Globeville soils are found on similar landscape positions, as well as on nearby plains. Globeville soils have fine loamy particle size control sections, a nonacid reaction class, and form in human-transported materials over mixed eolian deposits or alluvium.
Milehigh soils are found on similar landscape positions. Milehigh soils have coarse-loamy particle size control sections, a nonacid reaction class, and form in human-transported materials over alluvium.
Racas soils are found in depressions and storm-water retention basins on floodways as well as in drainageways on plains. Racas soils have more clay and fewer rock fragments in the particle size control section and form in human-transported material over loess or alluvium derived from loess.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class: Well drained
Saturated hydraulic conductivity: Moderately high (0.4 to 3.6 cm/hr)
Flooding: None to rarely flooded from March through August
Ponding: None to rarely ponded from March through August

Some pedons may be saturated above 150 centimeters for brief periods.

USE AND VEGETATION:
Most areas are used for residential suburban development. Vegetation may include a mix of managed and unmanaged plant communities with a mix of native and non-native species. Many areas are vegetated with non-native ornamental landscaping and/or turfgrass associated with developed land uses. Some areas may exhibit weedy, invasive, and/or primary succession vegetation communities (e.g., abandoned lots and other unmanaged areas). The potential native vegetation is little bluestem, sideoats grama, winterfat, and skunkbush sumac.

DISTRIBUTION AND EXTENT:
Urban and other areas with human-modified landscapes on Holocene stream terraces along the South Platte River in the vicinity of Denver in north-central Colorado. MLRA 67B - Central High Plains, Southern Part. These soils are of small extent.

SOIL SURVEY REGION (SSRO) RESPONSIBLE: Raleigh, North Carolina (Special Projects Office)

SERIES ESTABLISHED: Denver County, Colorado, 2025

REMARKS:
Typical Pedon Taxonomic Features:
Ochric epipedon--The zone from 0 to 14 centimeters (^A horizon)
Human-transported materials--The zone from 0 to 145 centimeters (^A, ^C, ^Cu1, and ^Cu2 horizons)
Free carbonates--The zone from 14 to 200 centimeters (^C, ^Cu1, ^Cu2, and 2C horizons)
Artifacts--The zone from 70 to 145 centimeters (^Cu1 and ^Cu2 horizons)
Lithologic discontinuity--At a depth of 145 centimeters
Particle-size control section--The zone from 25 to 100 centimeters
Taxonomic Version: Keys to Soil Taxonomy, Thirteenth Edition (2022)
Other: Altitude name is based on Denver, Colorado's mile-high altitude.

ADDITIONAL DATA:
NASIS User Pedon ID: 2021CO031244

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National Cooperative Soil Survey
U.S.A.