Tripp County, 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 Tripp County, South Dakota.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Millboro silty clay, 3 to 6 percent slopes | 98K | Well drained | D | Very limited | Very limited |
| Millboro silty clay, 0 to 3 percent slopes | 57K | Well drained | D | Very limited | Very limited |
| Lakoma-Millboro silty clays, 6 to 9 percent slopes | 57K | Well drained | D | Very limited | Very limited |
| Doger loamy fine sand, 0 to 6 percent slopes | 45K | Well drained | A | Not limited | Very limited |
| Lakoma-Okaton silty clays, 6 to 15 percent slopes | 44K | Well drained | D | Very limited | Very limited |
| Sansarc-Opal clays, 9 to 25 percent slopes | 41K | Well drained | D | Very limited | Very limited |
| Valentine-Dunday complex, 3 to 9 percent slopes | 32K | Excessively drained | A | Not limited | Very limited |
| Reliance silty clay loam, 3 to 6 percent slopes | 26K | Well drained | C | Somewhat limited | Very limited |
| Anselmo-Longpine fine sandy loams, 10 to 20 percent slopes | 25K | Well drained | A | Somewhat limited | Very limited |
| Boro-Millboro silty clays, 6 to 9 percent slopes | 24K | Well drained | D | Very limited | Very limited |
| Okaton-Lakoma silty clays, 15 to 40 percent slopes | 22K | Well drained | D | Very limited | Very limited |
| Witten silty clay, 0 to 3 percent slopes | 21K | Moderately well drained | C | Very limited | Very limited |
| Boyd-Okaton association, 9 to 25 percent slopes | 20K | Well drained | D | Very limited | Very limited |
| Dunday-Doger loamy fine sands, 3 to 9 percent slopes | 19K | Somewhat excessively drained | A | Not limited | Very limited |
| Dunday loamy fine sand, 3 to 9 percent slopes, eroded | 18K | Somewhat excessively drained | A | Not limited | Very limited |
| Anselmo-Vetal fine sandy loams, 0 to 3 percent slopes | 18K | Well drained | A | Not limited | Very limited |
| Reliance silty clay loam, 0 to 3 percent slopes | 17K | Well drained | C | Somewhat limited | Very limited |
| Millboro silty clay, 6 to 9 percent slopes | 16K | Well drained | D | Very limited | Very limited |
| Anselmo fine sandy loam, 3 to 6 percent slopes | 16K | Well drained | A | Not limited | Very limited |
| Anselmo-Holt fine sandy loams, 3 to 9 percent slopes | 14K | Well drained | A | Not limited | Very limited |
What This Means
Building & Foundations
About 63% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes. A geotechnical assessment is recommended before building.
Septic Systems
About 100% 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.