Alaska Peninsula - Aniakchak and Unimak Area, Alaska

Survey Area AK718• Alaska

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 Alaska Peninsula - Aniakchak and Unimak 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
Southern Alaska Peninsula Mountains-Maritime Water, Saline	3.0M			Not rated	Not rated
Southern Alaska Peninsula Mountains-Maritime Upland-Mountains	1.1M	Well drained	B	Very limited	Very limited
Southern Alaska Peninsula Mountains-Maritime Upland-Rounded Mountains	1.1M	Well drained	B	Very limited	Very limited
Southern Alaska Peninsula Mountains-Maritime Alpine-Barren Mountains	735K			Very limited	Very limited
Southern Alaska Peninsula Mountains-Maritime Upland-Volcanic Mountains and Lowland-Flood Plains and Stream Terraces	706K	Somewhat excessively drained	B	Not limited	Very limited
Southern Alaska Peninsula Mountains-Maritime Upland-Glaciated Plains and Hills	522K	Well drained	B	Very limited	Very limited
Bristol Bay-Northern Alaska Peninsula Lowlands-Maritime Upland-Glaciated Plains, Ash Influenced	431K	Very poorly drained	B	Very limited	Very limited
Bristol Bay-Northern Alaska Peninsula Lowlands-Maritime Water, Fresh	250K			Not limited	Not limited
Southern Alaska Peninsula Mountains-Maritime Upland-Glaciated Plains, Hummocky	173K	Well drained	B	Somewhat limited	Very limited
Southern Alaska Peninsula Mountains-Maritime Lowland-Coastal Plains	144K	Very poorly drained	D	Very limited	Very limited
Bristol Bay-Northern Alaska Peninsula Lowlands-Maritime Upland-Glaciated Plains and Peatlands	64K	Very poorly drained	B/D	Very limited	Very limited
Bristol Bay-Northern Alaska Peninsula Lowlands-Maritime Lowlands-Coastal Plains, Low	56K	Very poorly drained	B/D	Very limited	Very limited
Southern Alaska Peninsula Mountains-Maritime Upland-Southern Kodiak Hills and Plains	21K	Well drained	B	Not limited	Somewhat limited
Southern Alaska Peninsula Mountains-Maritime Water, Fresh	18K			Not rated	Not rated
Southern Alaska Peninsula Mountains-Maritime Upland-Glaciated Plains and Hills, Wet	14K	Well drained	A	Very limited	Very limited
Bristol Bay-Northern Alaska Peninsula Lowlands-Boreal Lowland-Flood Plains and Terraces	10K	Somewhat poorly drained	B/D	Very limited	Very limited
Bristol Bay-Northern Alaska Peninsula Lowlands-Boreal and Northwest Maritimel-Glaciated Plains, Ash Influenced	4K	Well drained	A	Not limited	Very limited
Southern Alaska Peninsula Mountains-Maritime Upland-Southern Kodiak Mountains	2K	Well drained	B	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.

Entisols

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

Histosols

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

Inceptisols

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

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 49% of soils have significant building limitations, while the rest are generally suitable. Check specific sites carefully — conditions vary across the area.

Septic Systems

About 60% 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.