City of Rocks National Reserve, Idaho
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 City of Rocks National Reserve, Idaho.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Ola-Rock outcrop-Earcree complex, 35 to 55 percent slopes | 4K | Well drained | B | Very limited | Very limited |
| Itca-Birchcreek-Rock outcrop complex, 25 to 55 percent slopes | 2K | Well drained | D | Very limited | Very limited |
| Arbone loam, 4 to 12 percent slopes | 1K | Well drained | B | Not limited | Somewhat limited |
| Riceton loamy coarse sand, 4 to 12 percent slopes | 1K | Well drained | A | Not limited | Very limited |
| Birchcreek-Itca complex, 25 to 55 percent slopes | 952 | Well drained | D | Very limited | Very limited |
| Ola sandy loam, 6 to 20 percent slopes | 729 | Well drained | B | Somewhat limited | Very limited |
| Howcan-Searla complex, 12 to 55 percent slopes | 706 | Well drained | B | Very limited | Very limited |
| Kanlee-Rock outcrop-Earcree complex, 3 to 30 percent slopes | 696 | Well drained | C | Very limited | Very limited |
| Povey, extremely stony surface-Nurkey complex, 15 to 55 percent slopes | 660 | Well drained | B | Very limited | Very limited |
| Kanlee sandy loam, 4 to 12 percent slopes | 506 | Well drained | C | Very limited | Very limited |
| Pachic Haplocryolls, 15 to 45 percent slopes | 315 | Well drained | C | Very limited | Very limited |
| Povey, extremely stony surface-Ola complex, 35 to 60 percent slopes | 226 | Well drained | B | Very limited | Very limited |
| Povey very stony loam, 35 to 55 percent slopes | 203 | Well drained | B | Very limited | Very limited |
| Jimsage-Doodlelink complex, 40 to 60 percent slopes | 187 | Well drained | B | Very limited | Very limited |
| Raftriver loam, 2 to 4 percent slopes | 178 | Well drained | C | Not limited | Very limited |
| Chayson gravelly silt loam, 2 to 10 percent slopes | 163 | Well drained | C | Somewhat limited | Very limited |
| Chokecherry very channery sandy loam, 4 to 35 percent slopes | 160 | Well drained | D | Very limited | Very limited |
| Poisonhol loam, 8 to 15 percent slopes, extremely stony | 90 | Well drained | C | Somewhat limited | Very limited |
| Kanlee sandy loam, 12 to 25 percent slopes | 70 | Well drained | C | Very limited | Very limited |
| Howcan-Searla complex, 4 to 12 percent slopes | 63 | Well drained | B | Somewhat limited | Somewhat 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. A geotechnical assessment is recommended before building.
Septic Systems
About 89% 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.