Dewey County, South Dakota

Survey Area SD041• South Dakota

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 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 Dewey County, South Dakota. 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
Sansarc-Opal clays, 9 to 25 percent slopes	345K	Well drained	D	Very limited	Very limited
Water	98K			Not rated	Not rated
Opal clay, 3 to 9 percent slopes	83K	Well drained	D	Very limited	Very limited
Sansarc-Dupree, acid, clays, 6 to 25 percent slopes	82K	Well drained	D	Very limited	Very limited
Opal-Sansarc clays, 6 to 15 percent slopes	78K	Well drained	D	Very limited	Very limited
Dupree-Opal clays, 3 to 9 percent slopes	65K	Well drained	D	Very limited	Very limited
Vebar fine sandy loam, 3 to 6 percent slopes	54K	Well drained	B	Somewhat limited	Very limited
Morton silt loam, 2 to 6 percent slopes	44K	Well drained	C	Somewhat limited	Very limited
Rhoades-Daglum complex, 0 to 6 percent slopes	37K	Moderately well drained	D	Very limited	Somewhat limited
Wayden-Moreau silty clays, 25 to 40 percent slopes	36K	Well drained	D	Very limited	Very limited
Regent-Ridgeview silty clay loams, 2 to 6 percent slopes	36K	Well drained	D	Very limited	Very limited
Opal-Hurley complex, 0 to 9 percent slopes	35K	Well drained	D	Very limited	Very limited
Chantier clay, 2 to 9 percent slopes	33K	Well drained	D	Very limited	Very limited
Cabba-Lantry complex, 25 to 40 percent slopes	26K	Well drained	D	Very limited	Very limited
Hurley-Slickspots complex, 2 to 9 percent slopes	26K	Well drained	D	Very limited	Very limited
Morton-Lantry silt loams, 2 to 9 percent slopes	25K	Well drained	C	Somewhat limited	Very limited
Belfield-Reeder loams, 2 to 6 percent slopes	25K	Well drained	C	Very limited	Very limited
Moreau-Wayden silty clays, 9 to 25 percent slopes	24K	Well drained	D	Very limited	Very limited
Promise-Wendte clays, channeled, occasionally flooded	22K	Well drained	D	Very limited	Very limited
Promise clay, 3 to 6 percent slopes	18K	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.

Mollisols

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

Vertisols

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

Entisols

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

Inceptisols

Young but developing soils found in mountains and river terraces. Variable properties — check drainage and bedrock depth.

What This Means

Building & Foundations

About 81% 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 88% 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.