Rio Grande NF Area, Colorado, West Part, Parts of Archuleta, Conejos, Hinsdale, Mineral, Rio Grande, Saguache, and San Juan Counties
The dominant drainage class is Well drained and the dominant hydrologic group is C (slow infiltration, moderate 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 Rio Grande NF Area, Colorado, West Part, Parts of Archuleta, Conejos, Hinsdale, Mineral, Rio Grande, Saguache, and San Juan Counties.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Frisco-Agneston association, 5 to 50 percent slopes | 141K | Well drained | A | Very limited | Very limited |
| Seitz cobbly loam, 15 to 60 percent slopes | 111K | Well drained | C | Very limited | Very limited |
| Cryoboralfs-Rock outcrop complex, 35 to 75 percent slopes | 106K | Well drained | C | Very limited | Very limited |
| Leighcan-Frisco association, 5 to 60 percent slopes | 72K | Well drained | A | Very limited | Very limited |
| Cryumbrepts-Rock outcrop-Rubble land complex, 20 to 80 percent slopes | 69K | Well drained | D | Very limited | Very limited |
| Mirror-Teewinot association, 8 to 45 percent slopes | 64K | Well drained | B | Very limited | Very limited |
| Rock outcrop and Rubble land | 64K | D | Not rated | Not rated | |
| Frisco-Scout association, 15 to 60 percent slopes | 64K | Well drained | A | Very limited | Very limited |
| Leighcan-Endlich association, 2 to 50 percent slopes | 59K | Well drained | A | Very limited | Very limited |
| Endlich-Hechtman association, 5 to 60 percent slopes | 58K | Well drained | B | Very limited | Very limited |
| Tellura, moist-Seitz association, 15 to 60 percent slopes | 56K | Well drained | C | Very limited | Very limited |
| Pergrin-Agneston-Hechtman association, 15 to 60 percent slopes | 53K | Well drained | B | Very limited | Very limited |
| Cryaquolls-Cryoborolls association, 0 to 20 percent slopes | 52K | Poorly drained | C | Very limited | Very limited |
| Seitz-Winz association, 8 to 60 percent slopes | 48K | Well drained | C | Very limited | Very limited |
| Seitz cobbly loam, dry, 15 to 60 percent slopes | 45K | Well drained | C | Very limited | Very limited |
| Cryoborolls-Cryochrepts-Rock outcrop complex, 15 to 80 percent slopes | 37K | Well drained | C | Very limited | Very limited |
| Cryochrepts-Rock outcrop association, 5 to 70 percent slopes | 36K | Well drained | C | Very limited | Very limited |
| Tellura-Gothic association, 2 to 45 percent slopes | 34K | Well drained | C | Very limited | Very limited |
| Bowen, cool-Agneston association, 15 to 50 percent slopes | 33K | Well drained | C | Very limited | Very limited |
| Embargo-Tellura association, 12 to 50 percent slopes | 32K | Well drained | D | Very limited | Very limited |
What This Means
Building & Foundations
About 94% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes, poor drainage in some areas, flood-prone areas. A geotechnical assessment is recommended before building.
Septic Systems
About 94% 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.