Matanuska-Susitna Valley Area, Alaska
The most common soil here is Histosols, on about 17% of the land. Talkeetna and Nancy come next.
About 57% of the land drains well, and 37% stays wet for long stretches; groundwater comes within two feet of the surface under 47% of it.
USDA rates 85% of the land very limited for a standard septic drain field, and 66% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 17% of the land floods occasionally or more, and bedrock lies within 40 inches under 5% 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 soils you're most likely standing on
The biggest named soils in Matanuska-Susitna Valley Area, Alaska, each drawn five feet deep from its official USDA description, in its recorded colors.
Dots mark gravel; white flecks mark lime. Shares are by acres across the survey area, and each mapped patch usually mixes several of these soils.
The biggest mapped areas
The dominant drainage class is Very poorly drained and the dominant hydrologic group is D (very slow infiltration, high 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 Matanuska-Susitna Valley 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 |
|---|---|---|---|---|---|
| Histosols | 335K | Very poorly drained | D | Very limited | Very limited |
| Cryaquepts, depressional, 0 to 7 percent slopes | 91K | Very poorly drained | D | Very limited | Very limited |
| Water | 90K | Not rated | Not rated | ||
| Rock outcrop-Cryumbrepts association, extremely steep | 58K | Well drained | D | Very limited | Very limited |
| Nancy silt loam, 0 to 3 percent slopes | 53K | Well drained | B | Not limited | Very limited |
| Talkeetna, warm, and Talkeetna, thick surface soils, 15 to 45 percent slopes | 47K | Well drained | B | Very limited | Very limited |
| Tokositna, undulating-Chunilna complex | 44K | Well drained | B | Not limited | Somewhat limited |
| Tokositna, hilly-Chunilna complex | 42K | Well drained | B | Very limited | Very limited |
| Typic Cryaquents, 0 to 2 percent slopes | 42K | Very poorly drained | D | Very limited | Very limited |
| Nancy silt loam, sloping and moderately steep | 41K | Well drained | B | Not limited | Very limited |
| Cryods and Cryaquepts, cool, 0 to 35 percent slopes | 41K | Very poorly drained | B | Very limited | Very limited |
| Susivar-Moose River complex, 0 to 2 percent slopes | 40K | Somewhat poorly drained | C | Very limited | Very limited |
| Typic Cryaquents, coastal, 0 to 2 percent slopes | 34K | Very poorly drained | D | Very limited | Very limited |
| Cryods, low elevation, and Cryochrepts, 30 to 70 percent slopes | 33K | Well drained | B | Very limited | Very limited |
| Cryods, 35 to 90 percent slopes | 31K | Well drained | B | Very limited | Very limited |
| Benka silt loam, 0 to 3 percent slopes | 30K | Well drained | B | Not limited | Very limited |
| Talkeetna, low elevation-Deneka, low elevation association, steep and moderately steep | 28K | Well drained | B | Very limited | Very limited |
| Talkeetna, warm-Talkeetna, thick surface complex, hilly | 25K | Well drained | B | Very limited | Very limited |
| Kashwitna silt loam, 0 to 3 percent slopes | 25K | Well drained | B | Not limited | Very limited |
| Susivar and Niklavar fine sandy loams | 25K | Somewhat poorly drained | C | 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.
What This Means
Building & Foundations
About 66% 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 85% 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.