Soil survey area

Chugach National Forest - Kenai Peninsula West Area, Alaska

Survey Area AK706• Alaska
The short version

The most common soil here is E23-boreal alpine scrub-gravelly colluvial slopes, on about 12% of the land. E23-boreal subalpine scrub/meadow mosaic-silty till slopes and E23-boreal alpine scrub-silty hummocks come next.

About 70% of the land drains well, and 5% stays wet for long stretches; groundwater comes within two feet of the surface under 14% of it.

USDA rates 99% of the land very limited for a standard septic drain field, and 97% very limited for homes with basements. That means extra cost or special design, not that it can't be done.

Worth knowing: 66% of the land floods occasionally or more, and bedrock lies within 40 inches under 73% of it.

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 Well drained and the dominant hydrologic group is A (high infiltration, low 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 Chugach National Forest - Kenai Peninsula West Area, Alaska. Search your address to find the exact soil composition, drainage, and series details at your specific location.

Soil Map UnitAcresDrainageHydro GroupDwellingsSeptic
Cook Inlet Mountains-Boreal Alpine-Mountains 448K Well drainedVery limitedVery limited
Cook Inlet Mountains-Boreal Upland and Lowland-Valleys 94K Well drainedAVery limitedVery limited
Cook Inlet Mountains-Boreal Alpine-Barren Mountains 60K Very limitedVery limited
Southern Alaska Coastal Mountains-Maritime Subalpine and Alpine-Mountains 58K Very limitedVery limited
Cook Inlet Lowlands-Boreal Water, Saline 53K Very limitedVery limited
Southern Alaska Coastal Mountains-Maritime Water, Fresh 17K Very limitedVery limited
Alexander Archipelago-Gulf of Alaska Coast-Maritime Upland and Subalpine-Rounded Mountains 15K Very poorly drainedA/DVery limitedVery limited
102-Forested Ice Scoured Land 15K Somewhat excessively drainedAVery limitedVery limited
Andic Haplocryods-Lithic Haplocryods complex, 16 to 45 percent slopes 15K Well drainedAVery limitedVery limited
Southern Alaska Coastal Mountains-Maritime Alpine-Barren Mountains 13K Not ratedNot rated
Andic Haplocryods-Lithic Haplocryods complex, 9 to 25 percent slopes 11K Well drainedAVery limitedVery limited
Southern Alaska Coastal Mountains-Maritime Upland-Mountains 11K Moderately well drainedB/DVery limitedVery limited
Cook Inlet Lowlands-Boreal Lowland-Coastal Plains 9K Very poorly drainedB/DVery limitedVery limited
Andic Haplocryods-Lithic Haplocryods complex, 26 to 65 percent slopes 7K Well drainedAVery limitedVery limited
Southern Alaska Coastal Mountains-Maritime Lowland-Flood Plains and Terraces 3K Very poorly drainedA/DVery limitedVery limited
Typic Cryaquents-Clunie complex, 0 to 3 percent slopes 3K Poorly drainedA/DVery limitedVery limited
Andic Haplocryods-Lithic Haplocryods complex, 4 to 15 percent slopes 3K Well drainedASomewhat limitedVery limited
Typic Dystrocryepts-Histic Cryaquepts complex, 0 to 45 percent slopes 3K Well drainedAVery limitedVery limited
Typic Dystrocryepts-Andic Haplocryods-Histic Cryaquepts complex, 0 to 45 percent slopes 3K Well drainedAVery limitedVery limited
Andic Haplocryods-Lithic Haplocryods complex, 46 to 100 percent slopes 2K Well drainedAVery limitedVery 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.
Spodosols
Acidic forest soils with a leached layer. Common under conifers. Often have drainage issues from a compacted subsoil layer.
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.

What This Means

Building & Foundations

About 97% 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.

Look Up a Specific Address

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