Bitterroot Valley Area, Montana
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 Bitterroot Valley Area, Montana.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Perma-Whitlash families-Rock outcrop complex, breaklands | 12K | Well drained | A | Very limited | Very limited |
| Holter-Whitlash families, complex, dissected mountain slopes | 7K | Well drained | C | Very limited | Very limited |
| Riverrun-Canarway-Fredburr complex, 0 to 2 percent slopes, occassionally flooded | 6K | Moderately well drained | A | Very limited | Very limited |
| Whitlash, rubbly-Rock outcrop-Quast, stony complex, 15 to 50 percent slopes | 6K | Well drained | D | Very limited | Very limited |
| Gash, occasionally flooded-Riverrun, rarely flooded complex, 0 to 2 percent slopes | 5K | Moderately well drained | A | Very limited | Very limited |
| Riverwash-Water-Riverrun, frequently flooded complex, 0 to 2 percent slopes | 5K | Not rated | Not rated | ||
| Wheelbarrow-Pianohill-Rock outcrop, 15 to 45 percent slopes | 4K | Well drained | C | Very limited | Very limited |
| Macmeal-Kadygulch-Tolman families, complex, dissected mountain slopes | 4K | Well drained | B | Very limited | Very limited |
| Riverrun complex, 0 to 2 percent slopes, rarely flooded | 4K | Moderately well drained | A | Very limited | Very limited |
| Perma, extremely stony-Whitash, rubbly complex, 15 to 45 percent slopes | 4K | Well drained | B | Very limited | Very limited |
| Farnuf-Bitterroot-Wimper complex, 15 to 40 percent slopes | 4K | Well drained | B | Very limited | Very limited |
| Holter-Tolman families, complex, dissected mountain slopes | 4K | Well drained | C | Very limited | Very limited |
| Haccke-Quast-Wemple complex, 8 to 15 percent slopes | 4K | Well drained | B | Somewhat limited | Very limited |
| Curlew-Riverrun complex, 0 to 2 percent slopes, rarely flooded | 3K | Very poorly drained | B/D | Very limited | Very limited |
| Burnt Fork loam, 0 to 4 percent slopes | 3K | Well drained | B | Not limited | Very limited |
| Riverside cobbly sandy loam, 15 to 35 percent slopes | 3K | Excessively drained | A | Very limited | Very limited |
| Riverrun, rarely flooded-Gash, occasionally flooded-Curlew, rarely flooded complex, 0 to 2 percent slopes | 3K | Moderately well drained | A | Very limited | Very limited |
| Chereete-Riverrun, rarely flooded-Curlew, rarely flooded complex, 0 to 8 percent slopes | 3K | Excessively drained | A | Very limited | Very limited |
| Hamilton silt loam, 0 to 4 percent slopes | 3K | Well drained | B | Not limited | Somewhat limited |
| Burnt Fork-Wimper-Fairway complex, 1 to 35 percent slopes | 3K | Well drained | B | Very limited | Very limited |
What This Means
Building & Foundations
About 83% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes, poor drainage in some areas, flood-prone areas. A geotechnical assessment is recommended before building.
Septic Systems
About 90% 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.