Western Interior Rivers Area, Alaska

Survey Area AK654• Alaska

The dominant drainage class is Well drained and the dominant hydrologic group is D (very slow infiltration, high runoff). The most common soil order is Inceptisols — young soils with minimal horizon development but more than Entisols. 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 Western Interior Rivers Area, Alaska. 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
Yukon-Kuskokwim Highlands, Boreal and Subalpine Low Mountains	1.1M	Well drained	C	Very limited	Very limited
Yukon-Kuskokwim Highlands, Boreal and Subalpine Mountains	786K	Well drained	B	Very limited	Very limited
Yukon-Kuskokwim Highlands, Subalpine and Alpine Mountains	567K	Well drained	A	Very limited	Very limited
Yukon-Kuskokwim Highlands, Boreal Hills	563K	Well drained	D	Very limited	Very limited
Yukon-Kuskokwim Coastal Plain, Tundra Plains	535K	Poorly drained	D	Very limited	Very limited
Yukon-Kuskokwim Highlands, Boreal Low Sedimentary Mountains	473K	Well drained	B	Very limited	Very limited
Ahklun Mountains, Subalpine and Alpine Glaciated Mountains	343K	Well drained	B	Very limited	Very limited
Yukon-Kuskokwim Highlands, Subalpine and Alpine Glaciated Igneous Mountains	304K	Well drained	A	Very limited	Very limited
Interior Alaska Lowlands, Boreal Glaciated Uplands	301K	Very poorly drained	D	Very limited	Very limited
Interior Alaska Lowlands, Boreal Peatlands	296K	Very poorly drained	D	Very limited	Very limited
Interior Alaska Lowlands, Tundra Flood Plains and Terraces	271K	Poorly drained	D	Very limited	Very limited
Yukon-Kuskokwim Highlands, Kulukbuk Hills	265K	Well drained	B	Very limited	Very limited
Yukon-Kuskokwim Highlands, Boreal Glaciated Uplands	258K	Poorly drained	C	Very limited	Very limited
Interior Alaska Lowlands, Innoko River-Paimiut Slough Flood Plains	250K	Poorly drained	D	Very limited	Very limited
Interior Alaska Lowlands, Holitna River Flood Plains and Terraces	247K	Moderately well drained	A	Very limited	Very limited
Yukon-Kuskokwim Highlands, Boreal Uplands and Rhyolitic Mountains	233K	Well drained	B	Very limited	Very limited
Yukon-Kuskokwim Highlands, Portage Mountain Uplands	217K	Poorly drained	C	Very limited	Very limited
Yukon-Kuskokwim Coastal Plain, Tundra Uplands	214K	Poorly drained	D	Very limited	Very limited
Yukon-Kuskokwim Highlands, Boreal Flood Plains and Terraces	155K	Moderately well drained	A	Very limited	Very limited
Yukon-Kuskokwim Coastal Plain, Aniak River Flood Plain and Terraces	145K	Well drained	A	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.

Inceptisols

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

Entisols

Young soils with little development — found on floodplains, dunes, and steep slopes. Properties vary widely by setting.

Gelisols

Permafrost soils. Extremely challenging for construction and septic. Found almost exclusively in Alaska.

Spodosols

Acidic forest soils with a leached layer. Common under conifers. Often have drainage issues from a compacted subsoil layer.

What This Means

Building & Foundations

About 100% of soils are rated "very limited" for dwellings with basements. Specific challenges include steep slopes, poor drainage in some areas, flood-prone areas. 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.