Talkeetna and Chugach Mountains - Cook Inlet Area, Alaska

Survey Area AK770• Alaska

The dominant drainage class is Well drained and the dominant hydrologic group is A (high infiltration, low runoff). 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 Talkeetna and Chugach Mountains - Cook Inlet 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
Cook Inlet Mountains-Boreal Subalpine and Alpine-Rounded Mountains, Acid	551K	Well drained	A	Very limited	Very limited
Interior Alaska Mountains-Boreal Alpine-Barren Mountains	518K			Very limited	Very limited
Cook Inlet Mountains-Boreal Alpine-Mountains	437K	Well drained		Very limited	Very limited
Cook Inlet Mountains-Boreal Alpine-Barren Mountains	398K			Very limited	Very limited
Cook Inlet Mountains-Boreal Subalpine and Alpine-Mountains, Acid	395K	Well drained	A	Very limited	Very limited
Cook Inlet Mountains-Boreal Upland and Lowland-Valleys	296K	Well drained	A	Very limited	Very limited
Cook Inlet Lowlands-Boreal Upland-Till Plains	154K	Very poorly drained	B/D	Very limited	Very limited
Interior Alaska Mountains-Boreal Glaciated Plains and Hills	115K	Poorly drained	D	Very limited	Very limited
Interior Alaska Mountains-Boreal Alpine-Glaciated Plains and Hills	79K	Well drained	B	Very limited	Very limited
Interior Alaska Mountains-Boreal Alpine-Rugged Mountains	58K	Well drained	B	Very limited	Very limited
Cook Inlet Lowlands-Boreal Lowland-Flood Plains and Terraces	53K	Somewhat poorly drained	B	Very limited	Very limited
Interior Alaska Mountains-Boreal Alpine-Rounded Mountains	47K	Well drained	B	Very limited	Very limited
Cook Inlet Mountains-Boreal Upland-Rounded Mountains	46K	Well drained	A	Very limited	Very limited
Cook Inlet Lowlands-Boreal Lowland-Flood Plains, Terraces, and Fans	31K			Very limited	Very limited
Interior Alaska Mountains-Boreal Upland and Lowland-Mountain Valleys	30K	Well drained	B	Very limited	Very limited
Cook Inlet Mountains-Boreal Subalpine and Alpine-Rounded Mountains	24K	Well drained	A	Very limited	Very limited
Cook Inlet Lowlands-Boreal Lowland-Flood Plains and Terraces, Wet	18K	Very poorly drained	B/D	Very limited	Very limited
Copper River Basin-Boreal Upland-Lacustrine Plains	16K	Poorly drained	D	Very limited	Very limited
Southern Alaska Coastal Mountains-Maritime Alpine-Barren Mountains	15K			Not rated	Not rated
Cook Inlet Lowlands-Boreal Upland-Glaciated Plains and Hills	8K	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.

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.

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.

Gelisols

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

What This Means

Building & Foundations

About 99% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, 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.