Brooks Range and Davidson Mountains Area, Alaska

Survey Area AK751• Alaska

The dominant drainage class is Well drained and the dominant hydrologic group is B (moderate infiltration). The most common soil order is Spodosols — acidic forest soils with a distinctive leached layer, common under conifers. 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 Brooks Range and Davidson Mountains 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
Interior Brooks Range Mountains-Boreal Alpine-Rugged Mountains	1.1M	Well drained	B	Very limited	Very limited
Interior Brooks Range Mountains-Boreal Upland and Lowland-Glaciated Valleys	851K	Well drained	B	Very limited	Very limited
Interior Alaska Highlands-Boreal Upland-Hills and Plains	400K	Poorly drained	D	Very limited	Very limited
Interior Alaska Highlands-Boreal Upland and Alpine-Plains and Hills	362K	Poorly drained	D	Very limited	Very limited
Interior Brooks Range Mountains-Boreal Alpine and Subalpine-Rounded Mountains	297K	Well drained	B	Very limited	Very limited
Yukon Flats-Boreal Upland-Plains and Hills	250K	Poorly drained	D	Very limited	Very limited
Interior Brooks Range Mountains-Boreal Upland-Rounded Mountains	163K	Well drained	B	Very limited	Very limited
Interior Alaska Highlands-Boreal Upland and Subalpine-Rounded Mountains	160K	Well drained	B	Not limited	Very limited
Interior Brooks Range Mountains-Boreal Upland and Alpine-Glaciated Valleys	61K	Well drained	B	Very limited	Very limited
Interior Alaska Highlands-Boreal Alpine and Upland-Rugged Mountains	48K	Well drained	B	Very limited	Very limited
Interior Brooks Range Mountains-Boreal Alpine-Barren Mountains	45K			Very limited	Very limited
Interior Alaska Highlands-Boreal Upland-Rounded Mountains, Acid	44K	Well drained	A	Very limited	Very limited
Interior Alaska Highlands-Boreal Lowland-Flood Plains and Terraces	25K	Poorly drained	D	Very limited	Very limited
Interior Alaska Highlands-Boreal Alpine and Upland-Rounded Mountains, Acid	18K	Well drained	B	Very limited	Very limited
Interior Brooks Range Mountains-Boreal Alpine and Subalpine-Rugged Mountains, Calcareous	8K	Well drained	D	Very limited	Very limited
Interior Alaska Highlands-Boreal Upland and Alpine-Rugged Mountains	6K	Well drained	A	Very limited	Very limited
Interior Brooks Range Mountains-Boreal Water,Fresh	5K			Not limited	Not limited
Yukon Flats-Boreal Lowland-Alluvial Plains	4K	Somewhat poorly drained	B/D	Very limited	Very limited
Northern Brooks Range Mountains-Arctic Upland-Barren Mountains	2K			Very limited	Very limited
Northern Brooks Range Mountains-Arctic Upland-Rugged Mountains	744	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.

Spodosols

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

Gelisols

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

Inceptisols

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

Mollisols

Fertile grassland soils with thick, dark topsoil. Among the best for agriculture, building, and gardening.

Entisols

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

What This Means

Building & Foundations

About 95% 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 99% 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.