Custer and Pennington Counties Area, Prairie Parts, South Dakota
The dominant drainage class is Well drained and the dominant hydrologic group is D (very slow infiltration, high 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 Custer and Pennington Counties Area, Prairie Parts, South Dakota.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Samsil clay, 15 to 40 percent slopes | 122K | Well drained | D | Very limited | Very limited |
| Pierre-Samsil, moderately deep clays, 6 to 25 percent slopes | 83K | Well drained | D | Very limited | Very limited |
| Nunn loam, 2 to 6 percent slopes | 67K | Well drained | C | Somewhat limited | Very limited |
| Pierre clay, 6 to 20 percent slopes | 60K | Well drained | D | Very limited | Very limited |
| Nunn loam, 0 to 2 percent slopes | 55K | Well drained | C | Somewhat limited | Very limited |
| Zigweid-Nihill complex, 6 to 15 percent slopes | 40K | Well drained | B | Somewhat limited | Somewhat limited |
| Satanta loam, 0 to 2 percent slopes | 39K | Well drained | B | Not limited | Somewhat limited |
| Fairburn clay loam, 9 to 40 percent slopes | 37K | Well drained | D | Very limited | Very limited |
| Norrest silty clay loam, 6 to 15 percent slopes | 33K | Well drained | C | Very limited | Very limited |
| Lohmiller silty clay, channeled, 0 to 3 percent slopes, occasionally flooded | 32K | Well drained | C | Very limited | Very limited |
| Midway silty clay loam, 9 to 35 percent slopes | 31K | Well drained | D | Very limited | Very limited |
| Razor-Midway complex, 6 to 15 percent slopes | 31K | Well drained | D | Very limited | Very limited |
| Satanta loam, 2 to 6 percent slopes | 30K | Well drained | B | Not limited | Somewhat limited |
| Fairburn-Orella-Badland complex, 15 to 45 percent slopes | 26K | Well drained | D | Very limited | Very limited |
| Kyle clay, 2 to 6 percent slopes | 25K | Well drained | D | Very limited | Very limited |
| Samsil-Rock outcrop complex, 10 to 50 percent slopes | 23K | Well drained | D | Very limited | Very limited |
| Badland | 22K | Excessively drained | D | Very limited | Very limited |
| Whitewater-Orella clays, 3 to 9 percent slopes | 20K | Well drained | D | Very limited | Very limited |
| Ottumwa clay, 2 to 6 percent slopes | 19K | Well drained | C | Very limited | Very limited |
| Pierre clay, 2 to 6 percent slopes | 19K | Well drained | D | Very limited | Very limited |
What This Means
Building & Foundations
About 71% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes, flood-prone areas. 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.