Soil series profile

Clovelly soil series

Clovelly is a very poorly drained soil with a muck surface, mapped on 382,269 acres in 15 counties across 2 states. Hydrologic group C/D.

#822 by mapped area clayey Terric Haplosaprists (Histosols)

Drainage class
Very poorly drained
99% of mapped acres
Hydrologic group
C/D
74% of mapped acres
Typical topsoil pH
6.6
neutral · range 6.6–6.6
Mapped area
382k
acres in 15 counties, 2 states

Typical Clovelly profile

Texture and pH by depth

Typical Clovelly soil profile by depth 0 in 20 in 40 in 60 in 0–28 in · Oa · pH 6.6 Muck 28–79 in · Cg · pH 6.9 · 72% clay Clay
Depth to scale. More strongly shaded layers hold more clay. Horizon names are the soil survey's (A = topsoil, B = subsoil, C = parent material).
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Typical Clovelly horizons (representative values)
Depth Texture pH Clay Sand Organic matter
0–28 in (Oa) Muck 6.6 Not reported Not reported 45.5%
28–79 in (Cg) Clay 6.9 72% 2% 0.6%

Representative values from the most extensive Clovelly map unit (Clovelly muck, 0 to 0.2 percent slopes, very frequently flooded, survey area LA075). Other map units of this series vary within the series range.

Hands holding dark garden soil
Stock photo for illustration, not a sample of this soil series. Credit on the Sources & method page.

What this means

What Clovelly soil means for gardens, lawns and septic systems

For gardens

Typical topsoil in Clovelly soils is neutral: pH 6.6, the range most vegetables, flowers and lawn grasses prefer.

Organic muck or peat is the most common topsoil (99% of mapped Clovelly acres). It is rich and holds water, but is often wet, can be acidic, and settles when drained. The most common surface texture is muck (99% of mapped Clovelly acres).

99% of mapped Clovelly acres is somewhat poorly to very poorly drained, so soil stays soggy for long spells after rain and in wet seasons. Raised beds, plants that tolerate wet feet, and not working the soil while wet all help.

For lawns and yards

On 99% of mapped acres, rain soaks in slowly (hydrologic groups C and D, including dual groups that are D until drained). Expect runoff and puddles after heavy rain: core-aerate compacted lawns and keep ground sloping away from foundations.

A seasonal high water table comes within 18 inches of the surface on 99% of mapped acres, often in spring. Basements, sump pumps and lawns in low spots feel it first.

For a septic system

For conventional septic absorption fields, NRCS rates 99% of the acres in mapped Clovelly soils very limited, 0% somewhat limited and 0% not limited (2% not rated, such as urban land, pits or water).

Where the soil is very limited (slow permeability, a high water table, flooding, shallow bedrock or steep slopes), alternative systems such as mound or sand-filter designs are common and cost more.

Flooding is mapped on 99% of the acres (0% occasional, 99% frequent).

Only a licensed site evaluation or perc test at the actual lot decides whether a system is allowed and which design.

Generated from the mapped numbers above using fixed rules, not a site visit. See how these notes are written.

Where Clovelly soil is found

Mapped acres

Clovelly is mapped in Louisiana and Texas.

Counties with the most mapped Clovelly soil
County Acres Share of county land
Terrebonne Parish, LA 81,129 11.2%
Cameron Parish, LA 74,741 9.2%
Plaquemines Parish, LA 64,396 17.1%
St. Bernard Parish, LA 45,837 18.9%
Vermilion Parish, LA 40,242 5.7%
Orleans Parish, LA 18,092 17.6%
Jefferson Parish, LA 15,754 9.2%
Lafourche Parish, LA 14,446 2.4%
St. Tammany Parish, LA 13,378 2.5%
Calcasieu Parish, LA 7,150 1.1%
St. Mary Parish, LA 5,934 1.5%
St. Charles Parish, LA 794 0.5%
Jefferson County, TX 368 0.1%
Iberia Parish, LA 6 0.0%
St. Martin Parish, LA 4 0.0%

Septic absorption fields

NRCS rating, share of Clovelly acres

Not limited 0%
Somewhat limited 0%
Very limited 99%
Not rated 2%
Septic tank absorption field rating across mapped Clovelly acres. Scale 0 to 100% of mapped land.
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Septic tank absorption field rating across mapped Clovelly acres.
CategoryShare of acres
Not limited0.0%
Somewhat limited0.0%
Very limited98.5%
Not rated1.5%

Drainage, water table and flooding

Share of Clovelly acres

Depth to seasonal high water table
About 0 inches (median where reported); within 18 inches on 99% of acres.
Flooding
Mapped as flooding on 99% of acres (0% occasional, 99% frequent).
Slope
Typically 0–0% (median 0%).
Topsoil organic matter
Median 45.5%.

Drainage class

Excessively drained 0%
Somewhat excessively drained 0%
Well drained 0%
Moderately well drained 0%
Somewhat poorly drained 0%
Poorly drained 0%
Very poorly drained 99%
Not rated 1%
Drainage class across mapped Clovelly acres. Scale 0 to 100% of mapped land.
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Drainage class across mapped Clovelly acres.
CategoryShare of acres
Excessively drained0.0%
Somewhat excessively drained0.0%
Well drained0.0%
Moderately well drained0.0%
Somewhat poorly drained0.0%
Poorly drained0.0%
Very poorly drained99.0%
Not rated1.0%

Hydrologic soil group

A: fast infiltration (mostly sandy or gravelly) 0%
B: moderate infiltration 0%
C: slow infiltration 0%
D: very slow infiltration (clayey, shallow or wet) 19%
A/D: D as is, A if drained 6%
B/D: D as is, B if drained 0%
C/D: D as is, C if drained 74%
Not rated 2%
Hydrologic soil group across mapped Clovelly acres. Scale 0 to 100% of mapped land.
Show as a table
Hydrologic soil group across mapped Clovelly acres.
CategoryShare of acres
A: fast infiltration (mostly sandy or gravelly)0.0%
B: moderate infiltration0.0%
C: slow infiltration0.0%
D: very slow infiltration (clayey, shallow or wet)18.8%
A/D: D as is, A if drained5.7%
B/D: D as is, B if drained0.0%
C/D: D as is, C if drained74.1%
Not rated1.5%

Sources & data dates

Source
USDA NRCS Soil Survey Geographic Database (SSURGO), queried through Soil Data Access. Public domain.
Data date
SSURGO as published on November 3, 2026 (most recent survey area update October 26, 2026). NRCS refreshes SSURGO each October.
Scope
All map unit components named Clovelly (component kind "Series") in SSURGO: 382,269 acres.
Method
Shares are by mapped acres of Clovelly components. The profile comes from the single largest Clovelly component. Full methodology.

Independent reference site. No government affiliation or endorsement.

Full narrative description: USDA Official Soil Series Description for Clovelly.