Willamette National Forest, Oregon
The dominant drainage class is Well drained and the dominant hydrologic group is A (high infiltration, low 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 Willamette National Forest, Oregon.
| 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 |
What This Means
Building & Foundations
About 81% 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 86% 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.