Brule and Buffalo Counties, South Dakota
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 Brule and Buffalo Counties, South Dakota.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Highmore-Mobridge silt loams, 0 to 4 percent slopes | 99K | Well drained | B | Not limited | Somewhat limited |
| Highmore-Java complex, 1 to 5 percent slopes | 97K | Well drained | C | Somewhat limited | Very limited |
| Eakin-DeGrey silt loams, 0 to 2 percent slopes | 76K | Well drained | C | Not limited | Very limited |
| Sansarc-Opal clays, 9 to 25 percent slopes | 52K | Well drained | D | Very limited | Very limited |
| Glenham-Java-Prosper loams, 1 to 6 percent slopes | 46K | Well drained | C | Not limited | Very limited |
| Mobridge-Plankinton silt loams | 36K | Moderately well drained | B | Somewhat limited | Somewhat limited |
| Promise clay, 3 to 6 percent slopes | 30K | Well drained | D | Very limited | Very limited |
| Plankinton silt loam | 30K | Poorly drained | D | Very limited | Very limited |
| Water | 26K | Not rated | Not rated | ||
| Promise clay, 0 to 3 percent slopes | 25K | Well drained | D | Very limited | Very limited |
| Highmore-Java complex, 5 to 9 percent slopes | 25K | Well drained | C | Somewhat limited | Very limited |
| Opal-Promise clays, 6 to 9 percent slopes | 24K | Well drained | D | Very limited | Very limited |
| Mobridge silt loam, 0 to 2 percent slopes | 21K | Moderately well drained | C | Somewhat limited | Very limited |
| Chantier-Sansarc clays, 3 to 15 percent slopes | 17K | Well drained | D | Very limited | Very limited |
| Uly silt loam, 2 to 6 percent slopes | 17K | Well drained | B | Not limited | Somewhat limited |
| Java-Betts loams, 9 to 20 percent slopes | 13K | Well drained | B | Very limited | Very limited |
| Opal clay, 3 to 6 percent slopes | 11K | Well drained | D | Very limited | Very limited |
| Java-Glenham loams, 6 to 9 percent slopes | 11K | Well drained | B | Somewhat limited | Very limited |
| Beadle-Jerauld complex, 0 to 6 percent slopes | 11K | Well drained | C | Somewhat limited | Very limited |
| Betts-Java loams, 20 to 40 percent slopes | 10K | Well drained | C | Very limited | Very limited |
What This Means
Building & Foundations
About 31% of soils have significant building limitations, while the rest are generally suitable. Check specific sites carefully — conditions vary across the area.
Septic Systems
About 73% 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.