Western Interior Rivers Area, Alaska
The dominant drainage class is Well drained and the dominant hydrologic group is D (very slow infiltration, high runoff). 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 Western Interior Rivers Area, Alaska.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Yukon-Kuskokwim Highlands, Boreal and Subalpine Low Mountains | 1.1M | Well drained | C | Very limited | Very limited |
| Yukon-Kuskokwim Highlands, Boreal and Subalpine Mountains | 786K | Well drained | B | Very limited | Very limited |
| Yukon-Kuskokwim Highlands, Subalpine and Alpine Mountains | 567K | Well drained | A | Very limited | Very limited |
| Yukon-Kuskokwim Highlands, Boreal Hills | 563K | Well drained | D | Very limited | Very limited |
| Yukon-Kuskokwim Coastal Plain, Tundra Plains | 535K | Poorly drained | D | Very limited | Very limited |
| Yukon-Kuskokwim Highlands, Boreal Low Sedimentary Mountains | 473K | Well drained | B | Very limited | Very limited |
| Ahklun Mountains, Subalpine and Alpine Glaciated Mountains | 343K | Well drained | B | Very limited | Very limited |
| Yukon-Kuskokwim Highlands, Subalpine and Alpine Glaciated Igneous Mountains | 304K | Well drained | A | Very limited | Very limited |
| Interior Alaska Lowlands, Boreal Glaciated Uplands | 301K | Very poorly drained | D | Very limited | Very limited |
| Interior Alaska Lowlands, Boreal Peatlands | 296K | Very poorly drained | D | Very limited | Very limited |
| Interior Alaska Lowlands, Tundra Flood Plains and Terraces | 271K | Poorly drained | D | Very limited | Very limited |
| Yukon-Kuskokwim Highlands, Kulukbuk Hills | 265K | Well drained | B | Very limited | Very limited |
| Yukon-Kuskokwim Highlands, Boreal Glaciated Uplands | 258K | Poorly drained | C | Very limited | Very limited |
| Interior Alaska Lowlands, Innoko River-Paimiut Slough Flood Plains | 250K | Poorly drained | D | Very limited | Very limited |
| Interior Alaska Lowlands, Holitna River Flood Plains and Terraces | 247K | Moderately well drained | A | Very limited | Very limited |
| Yukon-Kuskokwim Highlands, Boreal Uplands and Rhyolitic Mountains | 233K | Well drained | B | Very limited | Very limited |
| Yukon-Kuskokwim Highlands, Portage Mountain Uplands | 217K | Poorly drained | C | Very limited | Very limited |
| Yukon-Kuskokwim Coastal Plain, Tundra Uplands | 214K | Poorly drained | D | Very limited | Very limited |
| Yukon-Kuskokwim Highlands, Boreal Flood Plains and Terraces | 155K | Moderately well drained | A | Very limited | Very limited |
| Yukon-Kuskokwim Coastal Plain, Aniak River Flood Plain and Terraces | 145K | Well drained | A | Very limited | Very limited |
What This Means
Building & Foundations
About 100% 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 100% 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.