Gallatin National Forest Area, Montana
The dominant drainage class is Well drained and the dominant hydrologic group is B (moderate infiltration). 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 Gallatin National Forest Area, Montana.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Typic Cryochrepts-Rock outcrop-Rubbleland complex, cirque headwalls | 120K | B | Not rated | Not rated | |
| Typic Cryochrepts-Rock outcrop complex, steep | 50K | Somewhat excessively drained | B | Very limited | Very limited |
| Rubble land, talus | 40K | A | Not rated | Not rated | |
| Typic Cryochrepts, glacial drift substratum | 36K | Somewhat excessively drained | B | Somewhat limited | Somewhat limited |
| Rock outcrop-Typic Cryochrepts-Typic Cryoborolls complex, south aspect, steep | 36K | B | Very limited | Very limited | |
| Dystric Cryochrepts-Rock outcrop complex, granitic substratum | 34K | Excessively drained | A | Very limited | Very limited |
| Rock outcrop-Typic Cryochrepts-Typic Cryoborolls complex, limestone substratum | 31K | B | Very limited | Very limited | |
| Mollic Cryoboralfs, mountain slopes, steep | 27K | Well drained | C | Very limited | Very limited |
| Rock outcrop-Argic Cryoborolls-Mollic Cryoboralfs complex, steep | 26K | Well drained | D | Very limited | Very limited |
| Mollic Cryoboralfs-Argic Cryoborolls complex, structurally controlled slopes, steep | 26K | Well drained | C | Very limited | Very limited |
| Mollic Cryoboralfs-Argic Cryoborolls-Rock outcrop complex, structurally controlled slopes, steep | 25K | Well drained | C | Very limited | Very limited |
| Aquic Cryoboralfs-Typic Cryoboralfs complex, landslides | 25K | Somewhat poorly drained | C | Somewhat limited | Very limited |
| Typic Cryochrepts, obsidian sand substratum | 25K | Well drained | A | Not limited | Very limited |
| Typic Cryochrepts, glacial drift substratum, steep | 24K | Somewhat excessively drained | B | Very limited | Very limited |
| Typic Argiborolls-Mollic Eutroboralfs-Rock outcrop association, steep | 23K | Well drained | B | Very limited | Very limited |
| Dystric Cryochrepts-Rock outcrop complex, steep | 22K | Well drained | B | Very limited | Very limited |
| Mollic Eutroboralfs-Typic Argiborolls-Rock outcrop complex, steep | 20K | Well drained | C | Very limited | Very limited |
| Dystric Cryochrepts, glaciated mountain ridges | 20K | Well drained | A | Somewhat limited | Very limited |
| Typic Cryochrepts-Rock outcrop complex, volcanic substratum | 20K | Somewhat excessively drained | B | Very limited | Very limited |
| Argic Cryoborolls-Typic Cryoborolls association, structurally controlled slopes | 19K | Well drained | C | Very limited | Very limited |
What This Means
Building & Foundations
About 59% of soils are rated "very limited" for dwellings with basements. Specific challenges include steep slopes, poor drainage in some areas. A geotechnical assessment is recommended before building.
Septic Systems
About 69% 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.