Big Bend National Park, Texas

Survey Area TX621• Texas

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 Big Bend National Park, Texas. 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
Corazones very gravelly sandy loam, 1 to 8 percent slopes	92K	Well drained	A	Not limited	Not limited
Lingua-Rock outcrop complex, 20 to 60 percent slopes	76K		D	Very limited	Very limited
Solis-Rock outcrop complex, 1 to 20 percent slopes	53K		D	Very limited	Very limited
Corazones very gravelly sandy loam, 1 to 30 percent slopes	48K	Well drained	A	Somewhat limited	Somewhat limited
Strawhouse-Stillwell complex, 1 to 8 percent slopes	45K	Well drained	D	Very limited	Very limited
Blackgap-Rock outcrop complex, 20 to 70 percent slopes	41K	Well drained	D	Very limited	Very limited
Chilicotal very gravelly fine sandy loam, 1 to 8 percent slopes	38K	Well drained	B	Not limited	Somewhat limited
Leyva-Rock outcrop complex, 10 to 30 percent slopes	37K	Well drained	D	Very limited	Very limited
Ninepoint clay loam, 0 to 3 percent slopes	32K	Well drained	C	Somewhat limited	Very limited
Geefour silty clay, 3 to 20 percent slopes	28K	Well drained	D	Very limited	Very limited
Blackgap-Rock outcrop complex, 10 to 30 percent slopes	27K	Well drained	D	Very limited	Very limited
Geefour silty clay, 10 to 45 percent slopes	21K	Well drained	D	Very limited	Very limited
Mariscal-Terlingua complex, 10 to 30 percent slopes	21K	Well drained	D	Very limited	Very limited
Bissett-Rock outcrop complex, 20 to 70 percent slopes	20K	Well drained	D	Very limited	Very limited
Blackgap-Rock outcrop complex, 1 to 16 percent slopes	20K	Well drained	D	Very limited	Very limited
Chilicotal-Paisano association, 5 to 30 percent slopes	19K	Well drained	B	Somewhat limited	Somewhat limited
Mariscal-Rock outcrop complex, 5 to 30 percent slopes	18K		D	Very limited	Very limited
Chillon very gravelly fine sandy loam, 1 to 3 percent slopes, rarely flooded	18K	Well drained	B	Very limited	Somewhat limited
Solis-Rock outcrop complex, 20 to 60 percent slopes	17K	Well drained	D	Very limited	Very limited
Bissett-Rock outcrop complex, 10 to 30 percent slopes	16K	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.

Aridisols

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

Entisols

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

Mollisols

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

What This Means

Building & Foundations

About 66% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes, flood-prone areas. A geotechnical assessment is recommended before building.

Septic Systems

About 68% 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.