La Plata County Area, Colorado

Survey Area CO669• Colorado

The dominant drainage class is Well drained and the dominant hydrologic group is D (very slow infiltration, high runoff). The most common soil order is Aridisols — dry-climate soils with limited organic matter and often calcium carbonate accumulation. 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 La Plata County Area, Colorado. 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
Zyme-Rock outcrop complex, 12 to 65 percent slopes	44K	Well drained	D	Very limited	Very limited
Witt loam, 3 to 8 percent slopes	42K	Well drained	C	Not limited	Very limited
Archuleta-Sanchez, stony, complex, 12 to 65 percent slopes	39K	Well drained	D	Very limited	Very limited
Arboles clay, 3 to 12 percent slopes	31K	Well drained	C	Very limited	Very limited
Falfa clay loam, 3 to 8 percent slopes	27K	Well drained	C	Very limited	Very limited
Dulce-Travessilla-Rock outcrop complex, 6 to 50 percent slopes	26K	Well drained	D	Very limited	Very limited
Zyme clay loam, 3 to 25 percent slopes	23K	Well drained	D	Very limited	Very limited
Ustic Torriorthents-Ustollic Haplargids complex, 12 to 60	22K	Well drained	B	Very limited	Very limited
Lazear-Rock outcrop complex, 12 to 65 percent slopes	21K	Well drained	D	Very limited	Very limited
Rock outcrop	19K		D	Very limited	Very limited
Bodot clay, 3 to 10 percent slopes	19K	Well drained	D	Somewhat limited	Very limited
Valto-Rock outcrop complex, 12 to 65 percent slopes	19K		D	Very limited	Very limited
Sili clay loam, 3 to 6 percent slopes	19K	Well drained	C	Very limited	Very limited
Pulpit loam, 3 to 12 percent slopes	16K	Well drained	C	Very limited	Very limited
Lazear stony loam, 6 to 25 percent slopes	15K	Well drained	D	Very limited	Very limited
Durango cobbly loam, 3 to 20 percent slopes	14K	Well drained	C	Somewhat limited	Very limited
Witt loam, 1 to 3 percent slopes	12K	Well drained	C	Not limited	Very limited
Horsethief very stony fine sandy loam, 20 to 65 percent slopes	12K	Well drained	C	Very limited	Very limited
Hesperus loam, 3 to 12 percent slopes	12K	Well drained	B	Not limited	Somewhat limited
Fortwingate-Rock outcrop complex, 6 to 25 percent slopes	11K		C	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.

Aridisols

Dry-climate soils with low organic matter. Often have caliche layers that make excavation difficult. Low shrink-swell is good for foundations.

Alfisols

Moderately weathered forest soils with clay-enriched subsoil. Productive for agriculture, generally good for building and septic.

Mollisols

Fertile grassland soils with thick, dark topsoil. Among the best for agriculture, building, and gardening.

Entisols

Young soils with little development — found on floodplains, dunes, and steep slopes. Properties vary widely by setting.

Vertisols

High-clay soils that shrink and swell dramatically. Fertile but challenging for foundations and septic systems.

What This Means

Building & Foundations

About 77% 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.