Animas-Dolores Area, Colorado, Parts of Archuleta, Dolores, Hinsdale, La Plata, Montezuma, San Juan, and San Miguel Counties
The most common soil here is Needleton, on about 8% of the land: a loam, a balanced mix that crumbles in your hand. Snowdon and Frisco come next.
About 89% of the land drains well.
USDA rates all of the land very limited for a standard septic drain field, and 92% 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 54% 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 Animas-Dolores Area, Colorado, Parts of Archuleta, Dolores, Hinsdale, La Plata, Montezuma, San Juan, and San Miguel 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 Mollisols — grassland soils with a thick, dark, fertile topsoil rich in organic matter. 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 Animas-Dolores Area, Colorado, Parts of Archuleta, Dolores, Hinsdale, La Plata, Montezuma, San Juan, and San Miguel 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 |
|---|---|---|---|---|---|
| Needleton-Snowdon-Rock outcrop complex, 30 to 80 percent slopes | 69K | Well drained | C | Very limited | Very limited |
| Rock outcrop | 65K | D | Very limited | Very limited | |
| Rubble land | 43K | Excessively drained | A | Very limited | Very limited |
| Snowdon-Rock outcrop complex, 30 to 65 percent slopes | 42K | Well drained | C | Very limited | Very limited |
| Rock outcrop-Snowdon complex, 45 to 75 percent slopes | 41K | D | Very limited | Very limited | |
| Whitecross-Rock outcrop complex, 45 to 75 percent slopes | 41K | Well drained | D | Very limited | Very limited |
| Graysill-Scotch complex, south aspect, 30 to 60 percent slopes | 41K | Well drained | C | Very limited | Very limited |
| Argiustolls-Haplustalfs-Rock outcrop complex, 30 to 80 percent slopes | 40K | Well drained | C | Very limited | Very limited |
| Scotch-Graysill complex, 30 to 60 percent slopes | 39K | Well drained | D | Very limited | Very limited |
| Jemco-Detra-Beje complex, 1 to 15 percent slopes | 38K | Well drained | C | Very limited | Very limited |
| Needleton-Haviland complex, 30 to 60 percent slopes | 35K | Well drained | C | Very limited | Very limited |
| Frisco-Horsethief complex, 30 to 75 percent slopes | 33K | Well drained | B | Very limited | Very limited |
| Dressel-Jersey complex, 30 to 80 percent slopes | 30K | Well drained | B | Very limited | Very limited |
| Burnson loam, 1 to 15 percent slopes | 24K | Well drained | C | Very limited | Very limited |
| Needleton stony loam, 30 to 65 percent slopes | 22K | Well drained | B | Very limited | Very limited |
| Granath-Fughes complex, 0 to 15 percent slopes | 21K | Well drained | B | Not limited | Very limited |
| Behanco-Powderhorn family complex, 0 to 15 percent slopes | 19K | Well drained | B | Not limited | Very limited |
| Frisco loam, 10 to 25 percent slopes | 15K | Well drained | B | Very limited | Very limited |
| Wauquie-Dolcan-Rock outcrop complex, 25 to 80 percent slopes | 15K | Well drained | D | Very limited | Very limited |
| Whitecross, very stony-Rock outcrop complex, 15 to 45 percent slopes | 14K | Well drained | D | Very limited | Very limited |
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 92% 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.