Marion County Area, Oregon
The dominant drainage class is Well drained and the dominant hydrologic group is C (slow infiltration, moderate 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 Marion County Area, Oregon.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Woodburn silt loam, 0 to 3 percent slopes | 64K | Moderately well drained | C | Very limited | Very limited |
| Amity silt loam | 50K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Nekia silty clay loam, 2 to 7 percent slopes | 24K | Well drained | C | Very limited | Very limited |
| Kinney cobbly loam, 20 to 50 percent slopes | 23K | Well drained | B | Very limited | Very limited |
| McCully clay loam, 30 to 50 percent slopes | 18K | Well drained | C | Very limited | Very limited |
| Cloquato silt loam | 18K | Well drained | B | Very limited | Very limited |
| Nekia silty clay loam, 7 to 12 percent slopes | 16K | Well drained | C | Very limited | Very limited |
| Concord silt loam | 14K | Poorly drained | C/D | Very limited | Very limited |
| Nekia silty clay loam, 12 to 20 percent slopes | 14K | Well drained | C | Very limited | Very limited |
| Kinney cobbly loam, 2 to 20 percent slopes | 12K | Well drained | B | Somewhat limited | Somewhat limited |
| Dayton silt loam | 12K | Poorly drained | D | Very limited | Very limited |
| Jory silty clay loam, 2 to 7 percent slopes | 12K | Well drained | C | Somewhat limited | Very limited |
| Wapato silty clay loam | 12K | Poorly drained | C/D | Very limited | Very limited |
| Clackamas gravelly loam | 11K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Henline extremely stony sandy loam, 55 to 80 percent slopes | 10K | Well drained | B | Very limited | Very limited |
| Woodburn silt loam, 3 to 12 percent slopes | 8K | Moderately well drained | C | Very limited | Very limited |
| Jory silty clay loam, 7 to 12 percent slopes | 8K | Well drained | C | Somewhat limited | Very limited |
| McCully clay loam, 50 to 70 percent slopes | 8K | Well drained | C | Very limited | Very limited |
| Willamette silt loam, 0 to 3 percent slopes | 8K | Well drained | B | Somewhat limited | Somewhat limited |
| McAlpin silty clay loam, 0 to 3 percent slopes | 7K | Moderately well drained | C | Very limited | Very limited |
What This Means
Building & Foundations
About 88% 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 94% 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.