National Petroleum Reserve - Brooks Foothills South Area, Alaska
The most common soil here is E45-Arctic dwarf scrub-gravelly frozen circles, on about 34% of the land. E45-Arctic dwarf scrub-gravelly colluvial slopes and E45-Arctic tussock-gravelly frozen colluvial slopes come next.
About 9% of the land drains well, and 91% stays wet for long stretches; groundwater comes within two feet of the surface under 99% of it.
USDA rates all of the land very limited for a standard septic drain field, and all very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: bedrock lies within 40 inches under 9% 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 Somewhat poorly drained and the dominant hydrologic group is B/D (varies with drainage). The most common soil order is Gelisols — permafrost soils found in very cold climates. 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 National Petroleum Reserve - Brooks Foothills South 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 |
|---|---|---|---|---|---|
| Arctic Foothills-Arctic Upland-Hills and Plains | 6.1M | Somewhat poorly drained | B/D | Very limited | Very limited |
| Northern Brooks Range Mountains-Arctic Upland-Rugged Mountains | 437K | Well drained | B | Very limited | Very limited |
| Northern Brooks Range Mountains-Arctic Upland-Rounded Mountains | 132K | Well drained | B | Very limited | Very limited |
| Arctic Foothills-Arctic Lowland-Flood Plains and Terraces | 92K | Poorly drained | D | Very limited | Very limited |
| Northern Brooks Range Mountains-Arctic Upland and Lowland-Glaciated Valleys | 59K | Poorly drained | D | Very limited | Very limited |
| Northern Brooks Range Mountains-Arctic Upland-Rugged Mountains, Calcareous | 22K | Well drained | A | Very limited | Very limited |
| Arctic Foothills-Arctic Upland-Glaciated Hills and Plains | 21K | Poorly drained | B/D | Very limited | Very limited |
| Northern Brooks Range Mountains-Arctic Upland-Barren Mountains | 13K | Very limited | Very limited | ||
| Western Brooks Range Mountains, Foothills, and Valleys-Boreal Alpine-Rugged Mountains | 8K | Very limited | Very limited | ||
| Western Brooks Range Mountains, Foothills, and Valleys-Boreal Alpine-Glaciated Valleys | 1K | Poorly drained | D | Very limited | Very limited |
| Western Brooks Range Mountains, Foothills, and Valleys-Boreal Alpine-Rugged Mountains, Calcareous | 800 | Well drained | B | Very limited | Very limited |
| Western Brooks Range Mountains, Foothills, and Valleys-Boreal Alpine-Rounded Mountains | 450 | 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 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. 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.