Union County, South Dakota
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 Union County, South Dakota.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Crofton-Nora complex, 6 to 11 percent slopes, eroded | 37K | Well drained | B | Somewhat limited | Somewhat limited |
| Alcester silty clay loam, 2 to 6 percent slopes | 26K | Well drained | C | Somewhat limited | Very limited |
| Forney silty clay | 16K | Poorly drained | D | Very limited | Very limited |
| Moody-Nora silty clay loams, 6 to 10 percent slopes | 15K | Well drained | B | Somewhat limited | Somewhat limited |
| Kennebec silty clay loam, 0 to 2 percent slopes, occasionally flooded | 12K | Moderately well drained | C | Very limited | Very limited |
| Wakonda-Worthing-Chancellor complex | 12K | Moderately well drained | C/D | Very limited | Very limited |
| Luton silty clay | 12K | Poorly drained | D | Very limited | Very limited |
| Crofton silt loam, 12 to 20 percent slopes, eroded | 11K | Well drained | B | Very limited | Very limited |
| Moody silty clay loam, 2 to 6 percent slopes | 11K | Well drained | C | Somewhat limited | Very limited |
| Calco silty clay loam, wet, 0 to 2 percent slopes, occasionally flooded | 9K | Very poorly drained | C/D | Very limited | Very limited |
| McPaul silt loam, 0 to 2 percent slopes, occasionally flooded | 9K | Well drained | B | Very limited | Very limited |
| Wentworth silty clay loam, 0 to 2 percent slopes | 9K | Well drained | C | Somewhat limited | Very limited |
| Albaton silty clay | 8K | Poorly drained | D | Very limited | Very limited |
| Haynie silt loam | 7K | Well drained | B | Very limited | Somewhat limited |
| Onawa silty clay | 6K | Somewhat poorly drained | C | Very limited | Very limited |
| Modale silt loam | 6K | Moderately well drained | C | Very limited | Very limited |
| Norway loamy sand | 5K | Poorly drained | A/D | Very limited | Very limited |
| Benclare silty clay loam, somewhat poorly drained | 5K | Somewhat poorly drained | D | Very limited | Very limited |
| Blyburg silt loam | 5K | Well drained | B | Very limited | Somewhat limited |
| Wentworth-Worthing silty clay loams | 4K | Well drained | C/D | Somewhat limited | Very limited |
What This Means
Building & Foundations
About 54% of soils are rated "very limited" for dwellings with basements. Specific challenges include poor drainage in some areas, flood-prone areas. A geotechnical assessment is recommended before building.
Septic Systems
About 71% 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
Drainage is generally favorable for gardening. Adding compost and mulch will improve fertility and water retention. Test your soil's pH before planting — most vegetables prefer 6.0-7.0.