Olympic National Forest Area, Washington (Parts of Clallam, Grays Harbor, Jefferson, and Mason Counties)

Survey Area WA632• Washington

The dominant drainage class is Well drained and the dominant hydrologic group is B (moderate infiltration). The most common soil order is Andisols — soils formed in volcanic ash, very light and porous. This report summarizes the major soil map units across the survey area to help you understand what to expect when buying, building, or gardening in Olympic National Forest Area, Washington (Parts of Clallam, Grays Harbor, Jefferson, and Mason Counties). Search your address to find the exact soil composition, drainage, and series details at your specific location.

Soil Map Unit	Acres	Drainage	Hydro Group	Dwellings	Septic
Rock outcrop-Rubble land complex, 15 to 100 percent slopes	40K			Very limited	Very limited
Skookumcreek-Bonjonpass-Mountscott complex, 0 to 100 percent slopes	17K	Well drained	A	Very limited	Very limited
Waketickeh-Fricaba complex, 60 to 100 percent south slopes	13K	Well drained	D	Very limited	Very limited
Fricaba-Waketickeh-Duckabush complex, 60 to 90 percent south slopes	11K	Well drained	B	Very limited	Very limited
Rock outcrop-Haplocryands association, glacial trough, 60 to 100 percent slopes	11K			Very limited	Very limited
Sawpeak-Walkinshaw-McGravey complex, 60 to 90 percent north slopes	10K	Well drained	B	Very limited	Very limited
Larsencreek-Elklake-Eatoncreek complex, 60 to 100 percent north slopes	9K	Well drained	B	Very limited	Very limited
Aristine-Brokenfinger complex, 30 to 60 percent north slopes	9K	Moderately well drained	C/D	Very limited	Very limited
Fricaba-Waketickeh-Duckabush complex, low precipitation, 60 to 90 percent south slopes	9K	Well drained	B	Very limited	Very limited
Sorethumb-Blackjack complex, 50 to 100 percent south slopes	9K	Well drained	C	Very limited	Very limited
Hapludands and Dystrudepts soils, 50 to 90 percent slopes	9K	Well drained	A	Very limited	Very limited
Sappho-Edenvalley-Pysht complex, 40 to 80 percent north slopes	9K	Well drained	C	Very limited	Very limited
McKinnon-Flatbottom-Lizardlake complex, 60 to 100 percent south slopes	9K	Well drained	B	Very limited	Very limited
Tunnelcreek-Juandefuca-Pennycreek complex, 60 to 90 percent south slopes	8K	Well drained	B	Very limited	Very limited
Solleks-Kestner complex, 15 to 50 percent slopes	8K	Well drained	C	Very limited	Very limited
Mudcreek gravelly loam, 5 to 20 percent slopes	8K	Moderately well drained	C/D	Very limited	Very limited
Tylerpeak-Bungalow-Mueller complex, 60 to 90 percent north slopes	8K	Well drained	B	Very limited	Very limited
Quinault-Murhut complex, 60 to 100 percent north slopes	8K	Well drained	D	Very limited	Very limited
Edenvalley-Sappho-Pysht complex, 15 to 40 percent slopes	8K	Well drained	C	Very limited	Very limited
Rock outcrop-Haplocryands-Rubble land association, cirque headwalls, 60 to 100 percent slopes	8K			Very limited	Very limited

Soil Orders in This Area

The USDA classifies every soil into one of 12 soil orders. Here are the dominant orders found in this survey area.

Andisols

Volcanic ash soils — light, porous, and fertile. Excellent drainage, but low density can complicate foundations.

Alfisols

Moderately weathered forest soils with clay-enriched subsoil. Productive for agriculture, generally good for building and septic.

Inceptisols

Young but developing soils found in mountains and river terraces. Variable properties — check drainage and bedrock depth.

What This Means

Building & Foundations

About 100% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes. A geotechnical assessment is recommended before building.

Septic Systems

About 100% of soils are rated "very limited" for septic absorption fields. Despite good drainage overall, limitations may stem from shallow bedrock, steep slopes, or seasonal conditions. Engineered or alternative systems are frequently required. Always get a professional perc test before purchasing land that needs septic.

Gardening & Agriculture

Well-drained soils on sloped terrain — good for most plants but watch for erosion. Terracing, contour planting, and mulching help retain moisture and topsoil. Drip irrigation is more effective than sprinklers on slopes.