Willamette National Forest, Oregon
The most common soil here is Uppersoda, on about 7% of the land: a gravelly medial loam, a balanced mix that crumbles in your hand. Separation and Patjens come next.
About 94% of the land drains well; groundwater comes within two feet of the surface under 5% of it.
USDA rates 91% of the land very limited for a standard septic drain field, and 82% 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 28% 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 Willamette National Forest, Oregon, 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 Well drained and the dominant hydrologic group is A (high infiltration, low runoff). The most common soil order is Andisols — soils formed in volcanic ash, very light and porous. 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 Willamette National Forest, Oregon. 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 |
|---|---|---|---|---|---|
| Separation medial fine sandy loam, 2 to 15 percent slopes, moist | 56K | Well drained | B | Not limited | Somewhat limited |
| Coolcamp-Menagerie gravelly medial silt loams, 45 to 90 percent slopes | 55K | Well drained | A | Very limited | Very limited |
| Patjens medial fine sandy loam, 2 to 30 percent slopes | 54K | Well drained | A | Very limited | Very limited |
| Menagerie-Ramcreek complex, 0 to 30 percent slopes | 49K | Well drained | B | Very limited | Very limited |
| Separation medial fine sandy loam, 2 to 15 percent slopes | 48K | Well drained | B | Not limited | Somewhat limited |
| Dorena-Mooseridge complex, 0 to 30 percent slopes | 43K | Well drained | D | Very limited | Very limited |
| Uppersoda gravelly medial loam, 30 to 75 percent slopes, south-facing, warm | 43K | Well drained | A | Very limited | Very limited |
| Battleax very gravelly medial loam, 30 to 75 percent slopes, cold | 37K | Well drained | A | Very limited | Very limited |
| Kinney-Mooseridge complex, low precipitation, 0 to 30 percent slopes | 36K | Well drained | B | Very limited | Very limited |
| Dutchoven-Kinney complex, 45 to 90 percent slopes, south-facing | 35K | Well drained | A | Very limited | Very limited |
| Soapgrass medial loam, 2 to 30 percent slopes | 35K | Well drained | A | Not limited | Very limited |
| Illahee, high precipitation-Browder complex, 45 to 90 percent slopes, south-facing | 35K | Well drained | A | Very limited | Very limited |
| Dutchoven-Kinney complex, 45 to 90 percent slopes | 32K | Well drained | A | Very limited | Very limited |
| Bohemia-Westfir, low precipitation, gravelly loams, 45 to 90 percent slopes | 32K | Well drained | A | Very limited | Very limited |
| Browder-Ramcreek complex, 0 to 30 percent slopes, low precipitation | 30K | Well drained | B | Very limited | Very limited |
| Singe, moist-Zing, taxadjunct gravelly loams, 0 to 30 percent slopes | 29K | Well drained | B | Very limited | Very limited |
| Singe-Vena, dry, gravelly loams, 45 to 90 percent slopes, south-facing | 27K | Well drained | B | Very limited | Very limited |
| Chucksney medial loam, 30 to 75 percent slopes, south-facing | 27K | Well drained | A | Very limited | Very limited |
| Soapgrass medial loam, 30 to 75 percent slopes, low precipitation | 27K | Well drained | A | Very limited | Very limited |
| Waldor loamy coarse sand, 0 to 8 percent slopes | 24K | Moderately well drained | B/D | 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 82% of soils are rated "very limited" for dwellings with basements. Specific challenges include steep slopes. A geotechnical assessment is recommended before building.
Septic Systems
About 91% 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.