34 21—Donegan very gravelly ashy sandy loam, 30 to 65 percent south slopes

21—Donegan very gravelly ashy sandy loam, 30 to 65 percent south slopes

 Map Unit Setting

 General location: Mountainsides in the southwestern corner of the park

Major land resource area (MLRA): 5

Elevation: 4,000 to 5,100 feet

Average annual precipitation: 40 to 50 inches

Average annual air temperature: 41 to 45 degrees F

Frost-free period: 30 to 70 days

 Map Unit Composition

 Donegan and similar soils: 90 percent

Minor components: 10 percent

 Characteristics of the Donegan and Similar Soils


 Landform: Mountains

Geomorphic position: Side slopes

Parent material: Ash mixed with colluvium derived from andesite

 Properties and qualities

 Slope: 30 to 65 percent

Percentage of surface covered with stones and boulders: 15 percent

Restrictive feature: Bedrock (paralithic) at a depth of 20 to 40 inches

Drainage class: Well drained

Permeability: Moderately slow

Flooding: Not present

Water table: Not present

Ponding: Not present

Available water capacity: About 6.3 inches

 Interpretive groups

Ecological site: Forestland—(005XY700OR) Psuedotsuga menziesii/Mahonia nervosa/Chimaphila umbellata

 Typical profile

 Oi—0 to 1 inch; slightly decomposed plant material

A—1 inch to 5 inches; very gravelly ashy sandy loam

Bw1—5 to 14 inches; very gravelly loam

Bw2—14 to 30 inches; extremely gravelly loam

Bw3—30 to 39 inches; extremely gravelly loam

Cr—39 to 43 inches; weathered bedrock

 Characteristics of the Minor Components

 Rock outcrop

 Percentage of map unit: 10 percent

Landform: Lava flow

Geomorphic position: Andesitic lava flows on mountainsides

 Major Soil Features and Properties Affecting Management

 Donegan soil

 • Steep and unstable slopes

• Rock fragments on surface

Crater Lake National Park, Oregon 43

• Rock fragments in soil profile

• Water erosion

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