St. Martin Parish, Louisiana

Survey Area LA099• Louisiana

The dominant drainage class is Very poorly drained and the dominant hydrologic group is D (very slow infiltration, high runoff). The most common soil order is Alfisols — moderately leached forest soils with a clay-enriched subsoil. 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 St. Martin Parish, Louisiana. 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
Fausse soils, 0 to 1 percent slopes, frequently flooded	104K	Very poorly drained	C/D	Very limited	Very limited
Water	58K			Not rated	Not rated
Dowling soils, 0 to 1 percent slopes, frequently flooded	49K	Very poorly drained	D	Very limited	Very limited
Convent silt loam, 0 to 1 percent slopes, frequently flooded	42K	Somewhat poorly drained	C	Very limited	Very limited
Sharkey clay, 0 to 1 percent slopes, rarely flooded, deltaic plain	29K	Poorly drained	D	Very limited	Very limited
Tensas silty clay loam, 0 to 1 percent slopes	26K	Somewhat poorly drained	D	Very limited	Very limited
Iberia silty clay, 0 to 1 percent slopes	24K	Poorly drained	D	Very limited	Very limited
Loreauville silt loam	22K	Somewhat poorly drained	C/D	Very limited	Very limited
Dowling clay, 0 to 1 percent slopes, frequently flooded, deltaic plain	22K	Very poorly drained	D	Very limited	Very limited
Dundee silt loam	21K	Somewhat poorly drained	C	Somewhat limited	Very limited
Sharkey clay, 0 to 1 percent slopes, frequently flooded, deltaic plain	21K	Poorly drained	D	Very limited	Very limited
Fausse association, 0 to 1 percent slopes, frequently flooded	19K	Very poorly drained	D	Very limited	Very limited
Carville-Barbary association	18K	Somewhat poorly drained	C	Very limited	Very limited
Convent association, occasionally flooded	18K	Somewhat poorly drained	C	Very limited	Very limited
Carville soils, undulating, frequently flooded	7K	Somewhat poorly drained	C	Very limited	Very limited
Gallion-Perry complex, gently undulating	6K	Well drained	B	Somewhat limited	Somewhat limited
Dundee-Sharkey complex, gently undulating	5K	Somewhat poorly drained	C	Somewhat limited	Very limited
Baldwin silty clay loam, 0 to 1 percent slopes	5K	Poorly drained	D	Very limited	Very limited
Schriever clay, 0 to 1 percent slopes, rarely flooded	4K	Poorly drained	D	Very limited	Very limited
Memphis-Frost complex, gently undulating	4K	Well drained	B	Not limited	Somewhat 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.

Alfisols

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

Inceptisols

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

Vertisols

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

What This Means

Building & Foundations

About 81% of soils are rated "very limited" for dwellings with basements. Specific challenges include poor drainage in some areas, flood-prone areas. A geotechnical assessment is recommended before building.

Septic Systems

About 86% of soils are rated "very limited" for septic absorption fields. Poorly drained soils can't absorb septic effluent effectively. Engineered or alternative systems are frequently required. Always get a professional perc test before purchasing land that needs septic.

Gardening & Agriculture

Many soils hold water for extended periods. Raised beds are highly recommended to improve drainage for vegetables. Well-adapted native plants and water-loving species will do best in natural conditions.