Soil survey area

Yukon River Lowlands and Innoko National Wildlife Refuge South Area, Alaska

Survey Area AK727• Alaska

The short version

The most common soil here is E30-boreal taiga-silty frozen loess slopes, on about 22% of the land. E29-boreal taiga-organic frozen peat plateaus and E29-boreal taiga-loamy frozen terraces come next.

About 4% of the land drains well, and 96% stays wet for long stretches; groundwater comes within two feet of the surface under 96% of it.

USDA rates all of the land very limited for a standard septic drain field, and all very limited for homes with basements. That means extra cost or special design, not that it can't be done.

Worth knowing: 3% of the land floods occasionally or more.

Soils change over short distances, so look up an address below for the soil at that exact spot and the reasons behind each rating.

The biggest mapped areas

The dominant drainage class is Poorly drained and the dominant hydrologic group is D (very slow infiltration, high runoff). The most common soil order is Gelisols — permafrost soils found in very cold climates. 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 Yukon River Lowlands and Innoko National Wildlife Refuge South 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 Upland-Plains and Hills	1.1M	Poorly drained	D	Very limited	Very limited
Interior Alaska Lowlands-Boreal Lowland-Stream Terraces and Peat Plateaus	989K	Poorly drained	D	Very limited	Very limited
Interior Alaska Lowlands-Boreal Lowland-High Flood Plains and Terraces, Wet	455K	Very poorly drained	A/D	Very limited	Very limited
Yukon-Kuskokwim Highlands-Boreal Upland-Loess Hills	285K	Poorly drained	D	Very limited	Very limited
Interior Alaska Lowlands-Boreal Lowland-Flood Plains and Terraces, Wet	178K	Very poorly drained	B/D	Very limited	Very limited
Interior Alaska Highlands-Boreal Lowland-Flood Plains and Terraces	120K	Very poorly drained	B/D	Very limited	Very limited
Interior Alaska Lowlands-Boreal Lowland-Flood Plains and Terraces, High Elevation	82K	Poorly drained	D	Very limited	Very limited
Interior Alaska Lowlands-Boreal Lowland-Flood Plains and Terraces	78K	Poorly drained	B	Very limited	Very limited
Yukon-Kuskokwim Highlands-Boreal Upland and Alpine-Rounded Mountains	76K	Well drained	B	Very limited	Very limited
Yukon-Kuskokwim Highlands-Boreal Upland-Valleys	51K	Poorly drained	D	Very limited	Very limited
Interior Alaska Lowlands-Boreal Lowland-Fan Terraces and Stream Terraces	42K	Poorly drained	D	Very limited	Very limited
Yukon-Kuskokwim Highlands, Boreal and Subalpine Low Mountains	35K	Well drained	C	Very limited	Very limited
Interior Alaska Lowlands, Innoko River-Paimiut Slough Flood Plains	25K	Poorly drained	D	Very limited	Very limited
Yukon-Kuskokwim Highlands-Boreal Upland-Rounded Mountains	16K	Well drained	B	Very limited	Very limited
Interior Alaska Lowlands, Tundra Flood Plains and Terraces	4K	Poorly drained	D	Very limited	Very limited
Yukon-Kuskokwim Highlands-Boreal Upland and Lowland-Valleys and Flood Plains	1K	Poorly drained	D	Very limited	Very limited
Boreal Flood Plains	493	Moderately well drained	B	Very limited	Very limited
Interior Alaska Lowlands, Water	253			Not rated	Not rated

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.

Gelisols

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

Entisols

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

Spodosols

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

Inceptisols

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

Histosols

Organic peat and muck soils formed in wetlands. Very poor for building (compressible) and septic. Often in regulated wetlands.

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. Poorly drained soils can't absorb septic effluent effectively. Engineered or alternative systems are frequently required. Always get a professional perc test before purchasing land that needs septic.

Gardening & Agriculture

Many soils hold water for extended periods. Raised beds are highly recommended to improve drainage for vegetables. Well-adapted native plants and water-loving species will do best in natural conditions.