Piedra Area, Colorado, Parts of Archuleta, Hinsdale, La Plata, Mineral, and Rio Grande Counties
The most common soil here is Corta, on about 9% of the land: a silt loam, smooth, like flour. Carracas and Dunton come next.
About 76% of the land drains well, and 5% stays wet for long stretches.
USDA rates 81% of the land very limited for a standard septic drain field, and 81% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 1% of the land floods occasionally or more, and bedrock lies within 40 inches under 29% of it.
Soils change over short distances, so look up an address below for the soil at that exact spot and the reasons behind each rating.
The soils you're most likely standing on
The biggest named soils in Piedra Area, Colorado, Parts of Archuleta, Hinsdale, La Plata, Mineral, and Rio Grande Counties, each drawn five feet deep from its official USDA description, in its recorded colors.
Dots mark gravel; white flecks mark lime. Shares are by acres across the survey area, and each mapped patch usually mixes several of these soils.
The biggest mapped areas
The dominant drainage class is Well drained and the dominant hydrologic group is C (slow infiltration, moderate runoff). The most common soil order is Alfisols — moderately leached forest soils with a clay-enriched subsoil. 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 Piedra Area, Colorado, Parts of Archuleta, Hinsdale, La Plata, Mineral, and Rio Grande Counties. Search your address to find the exact soil composition, drainage, and series details at your specific location.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Dunton loam, 4 to 25 percent slopes | 66K | Well drained | C | Very limited | Very limited |
| Igneous outcrop-Cryorthents complex | 59K | D | Not rated | Not rated | |
| Carracas loam, 25 to 65 percent slopes | 54K | Well drained | D | Very limited | Very limited |
| Corta silt loam, 25 to 65 percent slopes | 44K | Well drained | C | Very limited | Very limited |
| Leal sandy loam, 25 to 65 percent slopes | 44K | Well drained | A | Very limited | Very limited |
| Igneous outcrop | 41K | D | Not rated | Not rated | |
| Chris gravelly loam, 25 to 65 percent slopes | 38K | Well drained | C | Very limited | Very limited |
| Corta silt loam, 4 to 25 percent slopes | 36K | Well drained | C | Very limited | Very limited |
| Sandstone outcrop-Ustorthents complex | 30K | D | Not rated | Not rated | |
| Chris stony loam, 25 to 65 percent slopes | 27K | Well drained | C | Very limited | Very limited |
| Pagosa loam, 4 to 25 percent slopes | 27K | Well drained | C | Very limited | Very limited |
| Grenadier loam, 25 to 65 percent slopes | 27K | Well drained | C | Very limited | Very limited |
| Hunchback clay loam, 4 to 15 percent slopes | 19K | Somewhat poorly drained | C | Very limited | Very limited |
| Nunn loam, 4 to 25 percent slopes | 17K | Well drained | C | Very limited | Very limited |
| Castelleia loam, 4 to 25 percent slopes | 16K | Well drained | C | Very limited | Very limited |
| Carracas loam, 4 to 25 percent slopes | 16K | Well drained | D | Very limited | Very limited |
| Woodrock silt loam, 25 to 65 percent slopes | 14K | Well drained | C | Very limited | Very limited |
| Hossick gravelly loam, 25 to 65 percent slopes | 13K | Well drained | C | Very limited | Very limited |
| Woodrock silt loam, 4 to 25 percent slopes | 12K | Well drained | C | Very limited | Very limited |
| Rubble land | 11K | A | Not rated | Not rated |
Soil Orders in This Area
The USDA classifies every soil into one of 12 soil orders. Here are the dominant orders found in this survey area.
What This Means
Building & Foundations
About 81% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes, poor drainage in some areas. A geotechnical assessment is recommended before building.
Septic Systems
About 81% 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.