LOCATION MUDCREEK WAEstablished Series
TAXONOMIC CLASS: Medial-skeletal, ferrihydritic, isomesic Oxyaquic Fulvudands
TYPICAL PEDON: Mudcreek gravelly medial loam - forestland, on a 15 percent northwesterly aspect at an elevation of 390 feet in a Sitka spruce/swordfern-oxalis plant association. (When described on July 30, 1997, the soil was moist throughout. Colors are for moist soil unless otherwise stated. All textures are apparent field textures.)
Oi--0 to 1 inch; slightly decomposed needles, leaves, twigs, and cone fragments; abrupt smooth boundary. (0.5 to 2 inches thick)
Oa--1 to 3 inches; highly decomposed organic materials; common very fine, fine, medium, and coarse roots; abrupt smooth boundary. (1 to 4 inches thick)
A--3 to 6 inches; very dark grayish brown (10YR 3/2) gravelly medial loam, grayish brown (10YR 5/2) dry; weak very fine, fine, and medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; weakly smeary; few very fine, fine, and medium roots; few very fine and fine tubular and irregular pores; 30 percent gravel; very strongly acid (pH 4.6); clear wavy boundary. (2 to 7 inches thick)
Bw1--6 to 11 inches; strong brown (7.5YR 4/6) very gravelly medial loam, yellowish brown (10YR 5/6) dry; weak very fine, fine, and medium subangular blocky and weak very fine and fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; weakly smeary; few very fine and fine roots; few very fine and fine tubular and irregular pores; 40 percent gravel; strongly acid (pH 5.2); clear wavy boundary.
Bw2--11 to 17 inches; strong brown (7.5YR 4/6) very gravelly medial loam, yellowish brown (10YR 5/6) dry; weak very fine, fine, and medium subangular blocky and weak very fine and fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; weakly smeary; few very fine and fine roots; few very fine and fine tubular and irregular pores; 40 percent gravel, 5 percent cobbles; strongly acid (pH 5.4); clear wavy boundary.
Bw3--17 to 23 inches; strong brown (7.5YR 4/6) very gravelly medial loam, reddish yellow (7.5YR 6/6) dry; weak very fine, fine, and medium subangular blocky and weak very fine and fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; weakly smeary; few very fine roots; few very fine and fine tubular and irregular pores; 45 percent gravel, 5 percent cobbles; strongly acid (pH 5.4); clear wavy boundary.
Bw4--23 to 30 inches; strong brown (7.5YR 4/6) extremely gravelly medial loam, brownish yellow (10YR 6/6) dry; weak very fine, fine, and medium subangular blocky and weak very fine and fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; weakly smeary; few very fine roots; few very fine and fine tubular and irregular pores; 60 percent gravel, 5 percent cobbles; strongly acid (pH 5.4); abrupt wavy boundary.
Bw5--30 to 34 inches; dark brown (7.5YR 3/4) very gravelly medial sandy loam, strong brown (7.5YR 5/6) dry; weak very fine, fine, and medium subangular blocky and weak very fine and fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; moderately smeary; few very fine roots; few very fine and fine irregular pores; 45 percent gravel; strongly acid (pH 5.2); abrupt wavy boundary. (Combined thickness of the Bw horizon is 18 to 33 inches thick.)
2Cd--34 to 63 inches; olive gray (5Y 5/2) dense till that slakes to very gravelly sandy loam, gray (5Y 6/1) dry; massive; hard, brittle, slightly sticky and slightly plastic; few very fine irregular pores; 45 percent gravel, 5 percent cobbles; strongly acid (pH 5.4). (20 inches to many feet thick)
TYPE LOCATION: Grays Harbor County, Washington, about 0.7 mile east of the Falls Creek Campground, about 2,000 feet east and 3,500 feet north of the southwest corner of Section 21, T. 23 N., R. 9 W. (Latitude 47 degrees, 28 minutes, 10 seconds N., Longitude 123 degrees, 49 minutes, 47 seconds W.)
RANGE IN CHARACTERISTICS: Mean annual soil temperature is 47 to 51 degrees F. The difference between the mean summer and mean winter soil temperature is 5 to 9 degrees F. These soils are usually moist, and are dry 30 to 45 consecutive days in the soil moisture control section. Depth to dense till (densic material) is 20 to 40 inches. The particle-size control section from the mineral soil surface to dense till has andic soil properties with moist bulk density of 0.75 to 0.90 g/cc, acid-oxalate extractable aluminum plus one half of the acid-oxalate extractable iron of 2 to 4 percent, phosphate retention of 85 to 100 percent, and 15-bar water retention of 20 to 35 percent for air dried samples. Acid oxalate iron is 1.5 to 3.0 percent. It has 2 to 3 cmol/kg of aluminum. The particle-size control section has 8 to 18 percent field estimated clay and averages 35 to 60 percent coarse fragments.
The A horizon has hue of 10YR or 7.5YR moist and dry, value of 2 or 3 moist and 3 through 5 dry, and chroma of 2 or 3 moist and 2 through 4 dry. It is extremely acid or very strongly acid. It has 10 to 25 percent organic matter.
The Bw horizon has hue of 10YR or 7.5YR moist and dry, value of 3 or 4 moist and 4 through 7 dry, and chroma of 4 or 6 moist and dry. It is very gravelly medial loam, extremely gravelly medial loam, or very gravelly medial sandy loam. It is very strongly acid or strongly acid soil. It has 4 to 10 percent organic matter and is less than 7 percent below a depth of 20 inches.
The 2Cd horizon has hue of 2.5Y or 5Y moist and dry, value of 4 or 5 moist and 6 through 8 dry, and chroma of 2 through 4 moist and 1 through 3 dry. It is very gravelly sandy loam, extremely gravelly sandy loam, or extremely gravelly loamy sand. It is strongly acid or very strongly acid. It has moist bulk density of 1.50 to 2.00 g/cc.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Mudcreek soils are on ground moraines on till plains. Slopes are 5 to 35 percent. Elevation is 120 to 1200 feet. Average annual precipitation is 120 to 140 inches. Fog drip contributes to the effective precipitation totals. Average annual temperature is 46 to 48 degrees F. The frost-free season is 140 to 220 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ascar, Hoko, Knappton, Mopang, Necanicum, Southshore, and Vesta soils. Ascar soils are on mountain slopes and dissected mountain slopes and are moderately deep to bedrock. Knappton soils are on moderate relief mountain slopes and mountain slopes and are very deep and medial. Mopang soils are on ground moraines and glacial valleys and are deep and very deep and medial. Necanicum soils are on moderate relief mountain slopes, mountain slopes and dissected mountain slopes and are deep and very deep. Southshore soils are on glacial valleys and are deep to densic till material. Vesta soils are on glacial valleys and are medial over clayey. Hoko soils have cemented till at 20 to 40 inches and have redoximorphic features.
DRAINAGE AND PERMEABILITY: Moderately well drained; permeability is moderate to the till and slow or very slow in the till. Mudcreek soils have a perched seasonal zone of saturation between 1.5 and 3.5 feet from November through April; oxyaquic conditions.
USE AND VEGETATION: Timber production, wildlife habitat, recreation, and watershed. Native vegetation is western hemlock, sitka spruce, vine maple, western swordfern, Oregon oxalis, red huckleberry, Alaska huckleberry, salmonberry, threeleaf foamflower, deer fern, mosses, and fiveleaf bramble.
DISTRIBUTION AND EXTENT: Grays Harbor County, Washington; MLRA 4A. Series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Grays Harbor County, Washington, 2000; Olympic National Forest.
REMARKS: Diagnostic horizons and features recognized in this pedon are the following:
Ochric epipedon
Cambic horizon - 6 to 34 inches
Andic soil properties - 3 to 34 inches
Dense layer - 34 to 63 inches
All depths to diagnostic horizons and other features are measured from the top of the first mineral horizon.