Eldorado National Forest Area, California, Parts of Alpine, Amador, El Dorado, and Placer Counties
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 Eldorado National Forest Area, California, Parts of Alpine, Amador, El Dorado, and Placer Counties.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Rock outcrop | 123K | Excessively drained | D | Very limited | Very limited |
| Lithnip-Hawkinspeak-Rock outcrop complex, 30 to 75 percent slopes | 43K | Well drained | D | Very limited | Very limited |
| McCarthy-Ledmount association, 2 to 30 percent slopes | 32K | Well drained | B | Very limited | Very limited |
| Jocal loam, 5 to 30 percent slopes | 21K | Well drained | B | Very limited | Very limited |
| McCarthy gravelly sandy loam, 2 to 30 percent slopes | 20K | Well drained | B | Very limited | Very limited |
| Rock outcrop-Cryumbrepts association, 15 to 75 percent slopes | 17K | Excessively drained | D | Very limited | Very limited |
| Chaix-Pilliken coarse sandy loam, 5 to 30 percent slopes complex | 17K | Somewhat excessively drained | B | Very limited | Very limited |
| Lithic Xerumbrepts-Rock outcrop complex, 15 to 75 percent slopes | 17K | Somewhat excessively drained | D | Very limited | Very limited |
| Chaix-Pilliken coarse sandy loams, 30 to 75 percent slopes complex | 16K | Somewhat excessively drained | B | Very limited | Very limited |
| Xerumbrepts-Cryumbrepts, wet association, 5 to 50 percent slopes | 16K | Moderately well drained | A | Very limited | Very limited |
| Tinker-Rock outcrop, granitic-Cryumbrepts, wet complex, 2 to 30 percent slopes | 15K | Well drained | B | Very limited | Very limited |
| McCarthy gravelly sandy loam, 30 to 50 percent slopes | 14K | Well drained | B | Very limited | Very limited |
| Lithic Cryumbrepts, 15 to 75 percent slopes | 14K | Excessively drained | D | Very limited | Very limited |
| Chaix coarse sandy loam, 30 to 75 percent slopes | 14K | Somewhat excessively drained | B | Very limited | Very limited |
| McCarthy-Ledmount association, 30 to 75 percent slopes | 13K | Well drained | B | Very limited | Very limited |
| Rock outcrop, granitic-Tinker-Cryumbrepts, wet complex, 30 to 75 percent slopes | 13K | Excessively drained | D | Very limited | Very limited |
| Water | 13K | D | Not rated | Not rated | |
| Cryumbrepts association, 5 to 50 prcent slopes | 13K | Well drained | A | Very limited | Very limited |
| Cohasset-McCarthy association, 2 to 30 percent slopes | 12K | Well drained | B | Very limited | Very limited |
| Tinker-Rock outcrop, granitic-Cryumbrepts, wet complex, 30 to 75 percent slopes | 11K | Well drained | B | Very limited | Very limited |
What This Means
Building & Foundations
About 97% 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 97% 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.