(1) Mixed Alluvial
This channel-dissected soil complex occurs in floodplains and
drainageways, and is susceptible to flooding1. Soil materials range from
soft organic silts and clays to dense gravel-sand-silt-clay alluvium. The
seasonal high water table varies from 0 to 2.5 feet below the surface.
Depth to hard bedrock ranges from 3 to 30 feet. Permeability is variable.
Soil strength may be poor because of soft soil and seasonal saturation.
Septic drainfields and infiltration trenches are poorly suited because of
wetness and flooding potential. Stream bank erosion within these soils
may result in undercutting of embankments on adjacent properties. Hydric
soils, which may include nontidal wetlands, occur within this mapping
unit2.
(2) Chewacla
Soils consist of silty and clayey alluvium eroded from schist, granite,
and gneiss. This soil occurs on floodplains and terraces adjacent to
active stream channels and is subject to flooding1. The seasonal high
water table is 0.5 to 1.5 feet below the surface. Depth to hard bedrock
ranges from 10 to 20 feet. Permeability is slow. Foundation support may
be poor because of soft soil and seasonal saturation. Basements below
existing grade are not recommended because of potential severe wetness
problems. Suitability for septic drainfields and infiltration trenches is
poor because of wetness, slow permeability and flooding potential. Hydric
soils occur in low areas within the Chewacla mapping unit2.
(3) Congaree
Soils consist of silty and clayey alluvium eroded from schists,
granites, and gneiss. This soil occurs along high terraces and
floodplains, and is subject to flooding1. The seasonal high water table
is 2.5 to 4 feet below the surface. Depth to hard bedrock ranges from 10
to 25 feet. Permeability is slow. Foundation support may be poor because
of soft soil and seasonal saturation. Foundation drains (exterior and
interior) and waterproofing are needed to prevent wet basement problems.
Suitability for septic drainfields and infiltration trenches is poor
because of wetness, slow permeability and flooding potential.
(5) Wehadkee
Soils consist of organic silts and clays eroded from schists, granites,
and gneiss. This soil occurs within floodplains and is subject to
flooding1. The seasonal high water table is 0 to 0.5 foot below the
surface. Depth to hard bedrock ranges from 8 to 20 feet. Permeability is
slow. Foundation support may be poor because of soft soil and seasonal
saturation. Basements below existing grade are not recommended because of
potential severe wetness problems. Suitability for septic drainfields and
infiltration trenches is poor because of wetness, slow permeability and
flooding potential. Wehadkee is predominantly hydric and may contain
potential nontidal wetlands2.
(6) Hyattsville
This soil occurs in drainageways and toe slopes, derived from Coastal
Plain sediments eroded from upper slopes. Soil materials include clay,
silt, sand and gravel. The seasonal high water table is one to two feet
below the surface. Depth to hard bedrock ranges from 10 to 200 feet or
more. Permeability is generally moderate. Foundation support may be
marginal because of soft soil and seasonal saturation. Foundation drains
(exterior and interior) and waterproofing are necessary to prevent wet
basements. Surface grading is often required to eliminate wet yards.
Suitability for septic drainfields and infiltration trenches is poor
because of the high water table.
(8) Worsham
This soil occurs in lower drainageways, depressions, and toe slopes,
derived from schists, granites, and alluvium. Soft clays and silts
overlie silty and sandy decomposed rock. The seasonal high water table is
0 to 0.5 foot below the surface. Depth to hard bedrock ranges from 20 to
100 feet. Permeability is slow in the surface and moderate to moderately
rapid in underlying materials. Foundation support may be poor because of
soft soil and seasonal saturation. Basements below existing grade are not
recommended because of potential severe wetness problems. Engineered
drainage designs are often required to eliminate wet yards. Suitability
for septic drainfields and infiltration trenches is poor because of the
seasonal high water table and slow permeability. Worsham is predominantly
hydric and may contain potential nontidal wetlands2.
(10) Glenville
This soil occurs in drainageways and footslopes, derived from schists,
granites, and alluvium. Clays and silts overlie silty and sandy
decomposed rock. The seasonal high water table is one to two feet below
the surface. Depth to hard bedrock ranges from 10 to 100 feet.
Permeability is moderate. Foundation support may be marginal because of
soft soil and seasonal saturation. Foundation drains (exterior and
interior) and waterproofing are necessary to prevent wet basements.
Surface grading is needed to eliminate wet yards. Suitability for septic
drainfields and infiltration trenches is poor because of the water table.
(11) Bermudian
Soils consist of silty and clayey alluvial sediments eroded from
sandstones, siltstones, and shales. This soil typically occurs at higher
elevations within the floodplains, and is subject to flooding1. The
seasonal high water table is 2.5 to 4 feet below the surface. Depth to
hard bedrock ranges from 4 to 14 feet. Permeability is moderate.
Foundation support may be poor because of soft soil and seasonal
saturation. Foundation drains (exterior and interior) and waterproofing
are needed to prevent wet basement problems. Suitability for septic
drainfields and infiltration trenches is poor because of the water table
and flooding potential.
(12) Rowland
Soils consist of silty and clayey alluvium eroded from sandstones,
siltstones, and shales. This soil occurs on middle-level floodplain
elevations, and is subject to flooding1. The seasonal high water table is
one to three feet below the surface. Depth to hard bedrock ranges from 4
to 10 feet. Permeability is slow. Foundation support may be poor because
of soft soil and seasonal saturation. Foundation drains (exterior and
interior) and waterproofing are needed to prevent wet basement problems.
Suitability for septic drainfields and infiltration trenches is poor
because of the water table and flooding potential. Hydric soils may occur
in low areas within the Rowland mapping unit2.
(13) Bowmansville
Soils consist of organic silt and clay alluvium eroded from sandstones,
siltstones, and shales. This soil occurs in the floodplain at the base of
adjoining upland slopes, and is subject to flooding1. The seasonal high
water tables is zero to one foot below the surface. Depth to hard bedrock
ranges from 4 to 12 feet. Permeability is slow. Foundation support may be
poor because of soft soil and seasonal saturation. Basements below
existing grade are not recommended because of potential severe wetness
problems. Suitability for septic drainfields and infiltration trenches is
poor because of wetness, slow permeability and flooding potential.
Bowmansville is predominantly hydric and may contain potential nontidal
wetlands2.
(14) Manassas
Soils consist of sandy, silty and clayey materials eroded from
sandstones and shales. This soil occurs in drainageways. The seasonal
high water table is one to two feet below the surface. Depth to hard
bedrock is from three to eight feet. Permeability is moderate. Foundation
support may be marginal because of soft soil in the upper two to four
feet and seasonal saturation. Foundation drains (exterior and interior)
and waterproofing are necessary to prevent wet basements. Surface grading
and subsurface drainage are often required to eliminate wet yards.
Suitability for septic drainfields and infiltration trenches is poor
because of the water table and shallow depth to rock. Use of the bedrock
as engineered fill, road embankment, and/or trench backfill is limited
due to rapid disintegration of the rocks.
(15) Muck
This organic-rich mineral soil occurs in the floodplain and is
susceptible to flooding1. Highly variable, stratified sandy, silty and
clayey sediments underlay the organic surface. The seasonal high water
table is at or above the surface for extended periods of time. Depth to
hard bedrock ranges from 20 to 300 feet. Permeability is generally slow.
Foundation support may be poor because of soft and very soft underlying
strata and seasonal saturation. Basements below existing grade are not
recommended because of potential severe wetness problems. Suitability for
septic drainfields and infiltration trenches is poor because of wetness
and flooding. Muck areas are largely wetland areas2.
(18) Rocky Land - Acidic Rock
Areas of shallow silty and sandy soils occur with schist, granite, and
gneiss outcrops and surface boulders. Outcrops and boulders occupy 15 to
40 percent of the surface. Depth to hard bedrock ranges from 0 to 6 feet.
Permeability is moderate to moderately rapid. Foundation support is good.
Shallow bedrock and stoniness make these soils difficult to excavate and
grade. Blasting may be required for below grade basements and
excavations. Suitability for septic drainfields and infiltration trenches
is poor because of shallow bedrock. This mapping unit generally occurs in
association with Manor and Louisburg soils.
(19) Very Rocky Land - Acidic
Rock
Areas of shallow silty and sandy soils occur with schist, granite, and
gneiss outcrops and surface boulders. Outcrops and boulders occupy
greater than 40 percent of the surface. Depth to hard bedrock ranges from
0 to 6 feet. Permeability is moderate to moderately rapid. Foundation
support is good. Shallow bedrock and stoniness make these soils difficult
to excavate and grade. Blasting may be required for below grade basements
and excavations. Suitability for septic drainfields and infiltration
trenches is poor because of shallow bedrock. This mapping unit generally
occurs in association with Manor and Louisburg soils.
(20) Meadowville
This soil occurs in drainageways and footslopes, derived from schists,
granites, and alluvium. Clays and silts overlie silty and sandy
decomposed rock. Depth to seasonal high water table ranges from two to
four feet. Depth to hard bedrock ranges from 10 to 100 feet. Permeability
is moderate. Foundation support may be marginal because of soft soil and
seasonal saturation. Foundation drains (exterior and interior) and
waterproofing are necessary to prevent wet basements. Grading is required
to eliminate wet yards. Suitability for septic drainfields and
infiltration trenches is poor because of the high water table.
(21) Manor
This silty and sandy soil occurs on sloping uplands underlain by
micaceous schist. Depth to hard bedrock ranges from 5 to 100 feet, but
may be shallower on steeper slopes. Permeability is moderate to
moderately rapid. Foundation support is good for small buildings (three
stories or less). A high mica content causes the soil to "fluff"
when disturbed. The soil is difficult to compact, requiring engineering
designs for use as structural fill. The soil is generally suitable for
septic drainfields and infiltration trenches. Manor is highly susceptible
to erosion.
(23)
Captina
This predominantly silty and clayey soil occurs on high stream terraces
along the Potomac River. A dense layer restricts drainage, creating a
perched water table 1.5 to 2 feet below the surface. Permeability is slow
in the subsurface. Foundation support is typically good. The subsoil may
affect subsurface drainage. Foundation drains and waterproofing are
needed to prevent wet basements. Suitability for septic drainfields and
infiltration trenches is poor because of slow permeability and the
perched water table. Grading and subsurface drainage are often required
to eliminate wet yards.
(24) Elioak
This soil occurs on hilltops underlain by micaceous schist. Silty clays
overlie silty and sandy decomposed rock. Depth to hard bedrock ranges
from 5 to 100 feet. Permeability is moderate. Foundation support is
favorable for small buildings (three stories or less). The soil is
suitable for septic drainfields and infiltration trenches. A high mica
content causes the soil to "fluff" up when disturbed. The soil is
difficult to compact, requiring engineering designs for use as structural
fill. Elioak is highly susceptible to erosion.
(26) Bertie
This soil consists of predominantly silty and clayey sediments on
relatively flat landscapes in the Coastal Plain. Sandy strata may occur
below four feet in some areas. The seasonal high water table is 1.5 to
2.5 feet below the surface. Depth to hard bedrock is greater than 50
feet. Permeability is moderately slow. Foundation support may be marginal
to poor because of soft soil and seasonal saturation. Foundation drains
(exterior and interior) and waterproofing are necessary to prevent wet
basements and crawl spaces. Surface grading and subsurface drainage may
be needed to eliminate wet yards. Suitability for septic drainfields and
infiltration trenches is poor because of the seasonal water table and
slow permeability.
(27, 29) Legore (Ruxton)
These gritty and silty upland soil is underlain by diorite/diabase
bedrock. The depth to hard rock is usually less than two feet.
Permeability in the soils above bedrock is moderately rapid. Foundation
support is favorable. Basements and excavations below existing grade may
require blasting of the hard rock. Suitability for septic drainfields and
infiltration trenches is marginal to poor because of the shallow depth to
rock.
(28) Montalto silt loam
Montalto occurs in association with plastic Iredell soils on hilltops
underlain by a diorite/diabase bedrock. A silty surface covers a clayey
subsoil of lower plasticity than Iredell. Depth to bedrock ranges from
two to six feet. Permeability is moderate. Foundation support is
generally favorable. Suitability for septic drainfields and infiltration
trenches is marginal to poor because of the shallow depth to rock.
(30) Huntington
This soil occurs on the first bottom floodplains adjacent to the Potomac
River, and is subject to flooding1. A silty surface overlies stratified
alluvial sediments. The seasonal high water table is three to five feet
below the surface. Depth to hard bedrock ranges from 15 to more than 100
feet. Permeability is moderate. Foundation support may be poor because of
soft soil and seasonal saturation. Foundation drains (exterior and
interior) and waterproofing are needed to prevent wet basement problems.
Suitability for septic drainfields and infiltration trenches is poor
because of flooding potential and the seasonal water table.
(31) Lindside
This soil occurs on the first bottom floodplains adjacent to the Potomac
River, and is subject to flooding1. Silty sediments overlie silty clay
alluvium. The seasonal high water table is 1.5 to 3 feet below the
surface. Depth to hard bedrock ranges from 15 to more than 100 feet.
Permeability is moderately slow. Foundation support may be poor because
of soft soils and seasonal saturation. Foundation drains (exterior and
interior) and waterproofing are needed to prevent wet basement problems.
Suitability for septic drainfields and infiltration trenches is poor
because of the water table and flooding potential.
(32) Fairfax silt loam
This upland soil consists of predominantly silty old alluvium, typically
3-7 feet thick, overlying silty and sandy decomposed rock. A
discontinuous dense layer results in a "perched" seasonal water
table at 1.5 to 2.5 feet below the surface. Depth to hard bedrock is 10
to 100 feet. Permeability is moderately slow in the dense layer and
moderate in the underlying soil. With proper drainage, the soil typically
provides adequate support for small buildings (3 stories or less).
Exterior foundation drains and waterproofing are necessary to prevent wet
basements. Grading and subsurface drains may be needed to eliminate wet
yards. Suitability for septic drainfields and infiltration trenches is
marginal because of slow permeability and the perched water table.
(33) Melvin
This soil occurs on the first bottom floodplains adjacent to the Potomac
River, and is subject to flooding1. Silty sediments overlie silty clay
alluvium. The seasonal high water table is zero to one foot below the
surface. Depth to hard bedrock ranges from 15 to more than 100 feet.
Permeability is moderate. Foundation support may be poor because of soft
soil and seasonal saturation. Basements below existing grade are not
recommended because of potential severe wetness problems. Suitability for
septic drainfields and infiltration trenches is poor because of wetness
and flooding potential. Melvin is predominantly hydric and may contain
potential nontidal wetlands2.
(34) Woodstown
This soil occurs in sandy sediments on nearly level landscapes in the
lower Coastal Plain. Soil materials are primarily sandy loams to sandy
clay loams, with a dense subsurface. The seasonal high water table is 1.5
to 2.5 feet below the surface. Depth to hard bedrock ranges from 50 to
more than 300 feet. Permeability is moderately rapid in the surface and
moderately slow in the subsurface. Foundation support may be marginal
because of soft soil and seasonal saturation. Foundation drains and
waterproofing are necessary to prevent wet basements and crawl spaces.
Grading and subsurface drainage may be needed to eliminate wet yards.
Suitability for septic drainfields and infiltration trenches is poor
because of the seasonal water table.
(35) Manteo
This shallow soil occurs primarily on steeper sideslopes underlain by
micaceous schist. A thin silty surface overlies partly weathered schist
and slate fragments. Depth to hard bedrock is usually less than 15
inches. Permeability is moderately rapid. The soil typically provides
favorable support for small buildings (three stories or less). Because of
a high mica content, the soil tends to "fluff" up when disturbed
and is difficult to compact, requiring engineering designs for use as
structural fill. Suitability for septic drainfields and infiltration
trenches is poor because of the shallow depth to rock. Manteo is highly
susceptible to erosion.
(37, 38) Beltsville
This gravelly and silty soil occurs on hilltops in the Coastal Plain and
on old Coastal Plain terraces over weathered schists and granites. A
dense layer is encountered at depths of 2 to 2.5 feet. Depth to hard
bedrock is typically greater than 50 feet. Permeability of the dense
layer is very slow, resulting in a perched seasonal high water table 1.5
to 2.5 feet below the surface. Foundation support is typically good with
proper drainage. Foundation drains and waterproofing are necessary to
prevent wet basements. Grading and subsurface drainage is usually
required to eliminate wet yards. Septic drainfields and infiltration
trenches are poorly suited because of slow permeability and the perched
water table.
(39) Othello
This silty and clayey soil occurs on nearly level landscapes in the
Coastal Plain. Lower areas along Dogue Creek are within the floodplain1.
Underlying strata vary from sand to soft clays. Organic strata (peat or
muck) may be encountered. The seasonal high water table is 0 to 0.5 foot
below the surface. Depth to bedrock is greater than 50 feet. Permeability
is slow in the surface and moderate to moderately rapid in underlying
sands. Foundation support may be poor because of soft to very soft
underlying strata and seasonal saturation. Basements below existing grade
are not recommended because of severe wetness problems. Engineered
drainage designs are often required to eliminate wet yards. Suitability
for septic drainfields and infiltration trenches is poor because of
wetness and slow permeability. Othello is predominantly hydric and may
contain potential nontidal wetlands2.
(40) Mecklenburg
This soil, formed in weathered diabase materials, occurs on hilltops and
sideslopes in close association with plastic Iredell soils. A silty
surface overlies a sticky plastic clay subsoil. Sandy clays and clayey
sands occur between the clay layer and bedrock in some places. A
"perched" seasonal high water table occurs above the clays, 3 to
4 feet below the surface. Depth to hard bedrock is usually from 3 to 15
feet. Permeability is slow. Foundation footings must extend below the
soft plastic clays, generally to bedrock, to ensure competent building
support. Foundation drains and waterproofing are necessary to prevent wet
basements and crawl spaces. Surface grading and subsurface drainage may
be needed to eliminate wet yards. Suitability for septic drainfields and
infiltration trenches is poor because of the perched water table, plastic
clays, and shallow depth to rock. Deep basements and excavations may
require blasting in hard bedrock.
(41) Rocky Land - (Iredell)
This mapping unit occurs on hilltops and sideslopes in association with
the Iredell soils in the diabase areas. Frequent rock outcrops or
boulders occupy 20 to 50 percent of the surface. Plastic clay subsoil may
occur one to three feet below the surface. The depth to seasonal high
water table varies from one to greater than ten feet. The depth to hard
bedrock varies from zero to 15 feet. Foundation support is good on
bedrock, but may be poor in areas with plastic clay subsoil. Suitability
for septic drainfields and infiltration trenches is poor because of
plastic clays and shallow depth to rock. The shallow bedrock and
stoniness make these soils difficult to excavate and grade. Deep
basements and excavations may require blasting in the hard bedrock.
(42) Very Rocky Land - (Iredell)
This mapping unit occurs on hilltops and sideslopes in association with
the Iredell soils in the diabase areas. Frequent rock outcrops or
boulders occupy over 50 percent of the surface. Plastic clay subsoil may
occur one to three feet below the surface. The depth to seasonal high
water table varies from one to greater than ten feet. The depth to hard
bedrock varies from zero to 15 feet. Foundation support is good on
bedrock, but may be poor in areas with plastic clay subsoil. Suitability
for septic drainfields and infiltration trenches is poor because of
plastic clays and shallow depth to rock. The shallow bedrock and
stoniness make these soils difficult to excavate and grade. Deep
basements and excavations may require blasting in the hard bedrock.
(43) Masada gravelly loam
Masada is found on high terraces, in loamy and gravelly material washed
from soils of the Piedmont Upland. A sticky, plastic clay subsoil may
restrict drainage and be difficult to manipulate and compact when wet.
Depth to hard bedrock ranges from 30 to 150 feet. Permeability is
moderately slow. Foundation support is typically good. Exterior
foundation drains and waterproofing are needed to prevent wet basements.
Grading and subsurface drainage are often required to eliminate wet
yards. Suitability for septic drainfields and infiltration trenches is
marginal because of slow permeability.
(44) Caroline
This soil occurs in clayey sediments on hilltops and sideslopes in the
Coastal Plain. A plastic clay subsoil may restrict drainage. Depth to
hard bedrock is greater than 30 feet. Permeability is moderately slow.
Foundation support is marginal because of the plastic clays. Foundation
drains and waterproofing are necessary to prevent wet basements. Grading
and subsurface drainage are often necessary to eliminate wet yards.
Septic drainfields and infiltration trenches are poorly suited because of
the clay and slow permeability.
(45) Matapeake
This soil occurs on uplands in sand, silt and clay sediments of the
lower Coastal Plain. Sandy clay loam, clay loam, and silty clay loam
soils are typical. A dense silty clay loam layer may be present two to
three feet below the surface in some areas. Depth to bedrock is typically
greater than 200 feet. Permeability is moderate, but may be moderately
slow where the dense layer is present. Foundation support is generally
favorable. Subsurface drainage may be needed to prevent wet basements and
yards where the dense layer occurs. Suitability for septic drainfields
and infiltration trenches is good, except in areas of dense soil.
(46) Mattapex
This soil occurs on uplands in sand, silt, and clay sediments of the
lower Coastal Plain. Sandy clay loam, clay loam, and silty clay loam
soils are typical. A dense layer occurs 2.5 to 3 feet below the surface.
A "perched" seasonal high water table is found above the dense
layer, one to two feet below the surface. Depth to hard bedrock is
typically greater than 200 feet. Permeability is moderately slow.
Foundation support may be marginal because of occasional soft soil and
seasonal saturation. Foundation drains and waterproofing are needed to
prevent wet basements. Grading and subsurface drainage are often
necessary to eliminate wet yards. Suitability for septic drainfields and
infiltration trenches is poor because of slow permeability and the
perched water table.
(47) Dragston
This soil occurs on nearly level uplands in sandy and clayey Coastal
Plain sediments. Sandy loams and sandy clay loams are predominant in the
upper five feet. The seasonal high water table is 1.5 to 2.5 feet below
the surface. Depth to hard bedrock is typically greater than 200 feet.
Permeability is moderately rapid. Foundation support may be marginal
because of seasonal saturation. Foundation drains (interior and exterior)
and waterproofing are needed to prevent wet basements. Grading and
subsurface drainage are often necessary to eliminate wet yards.
Suitability for septic drainfields and infiltration trenches is poor
because of the seasonal water table.
(48) Iredell
This highly plastic soil occurs on hilltops and sideslopes, formed in
weathered diabase materials. A silty surface overlies a sticky plastic
clay subsoil one to three feet thick. Sandy clays and clayey sands occur
below the clay layer. A perched seasonal high water table, above the
clays, is one to two feet below the surface. Depth to hard bedrock is
usually from 3 to 15 feet. Permeability is slow. Foundation footings must
extend below the soft plastic clays, generally to bedrock, to ensure
competent building support. Foundation drains, grading, and waterproofing
are necessary to prevent wet basements and crawl spaces. Grading and
subsurface drainage may be needed to eliminate wet yards. Suitability for
septic drainfields and infiltration trenches is poor because of the
plastic clays, perched water table, and shallow depth to bedrock. Deep
basements and excavations may require blasting.
(49) Lunt
This extremely variable soil is found on hilltops and sideslopes in
sands, silts, and clays of the Coastal Plain. Soil materials vary from
sands to clays. Where clay subsoils are present, a perched seasonal water
table may be present above the clay. Depth the hard bedrock is typically
greater than 75 feet. The soils are stable when underlain with sands.
However, Lunt soils in close proximity to areas of the Marine Clays
should be analyzed for foundation support and slope stability.
Permeability of the subsoil varies depending upon the soil material.
Foundation drains, grading, and waterproofing are necessary to prevent
wet basements and crawl spaces where clays are present. Suitability for
septic drainfields and infiltration trenches is good in the sandy subsoil
and poor in the clayey subsoil.
(50) Iredell-Mecklenburg, Stony
This highly plastic soil occurs on hilltops and sideslopes, derived from
weathered diabase. A silty surface covers a sticky plastic clay subsoil
one to three feet thick. Sandy clays and clayey sands occur below the
clay layer. Numerous surface boulders may be present. A perched seasonal
high water table, above the clay, is one to two feet below the surface.
Depth to hard bedrock is usually 3 to 15 feet. Permeability
(51) Keyport
This soil occurs on nearly level landscapes in predominantly silty and
clayey sediments of the Coastal Plain. Slowly permeable clays occur in
the subsoil and a seasonal high water table may be present within three
to four feet of the surface. Sandy strata may occur below five feet.
Depth to hard bedrock is greater than 200 feet. Foundation support is
fair provided that drainage is addressed. Foundation drains and
waterproofing are needed to prevent wet basements. Grading may be
necessary to eliminate wet yards. Suitability for septic drainfields and
infiltration is marginal to poor because of the water table and slow
permeability.
(52) Elbert - (Iredell Group)
This wet, plastic soil occurs in drainageways and footslopes in
materials derived from weathered diabase and alluvium. Slowly permeable
plastic clay subsoils occur 2 to 4 feet below the surface. The seasonal
high water table is 0 to 0.5 foot below the surface. The depth to bedrock
varies from 3 to 15 feet. Foundation footings must extend below the soft
plastic clays, generally to bedrock, to ensure competent building
support. Basements below existing grade are not recommended because of
potential severe wetness problems. Engineered drainage designs are often
required to eliminate wet yards. Septic drainfields and infiltration
trenches are poorly suited because of wetness, plastic clays and shallow
depth to bedrock. Elbert is predominantly hydric and may contain
potential nontidal wetlands2.
(53) Lenoir
This soil occurs in loamy and clayey sediments on nearly level
landscapes in the lower Coastal Plain. A silty surface overlies a slowly
permeable clayey subsoil which has a moderate shrink-swell potential. The
seasonal high water table is 0.5 to 1.5 feet below the surface. Depth to
bedrock is typically greater than 200 feet. Foundation support is
marginal because of the clays and seasonal saturation. Foundation drains
(exterior and interior), surface grading, and waterproofing are necessary
to prevent wet basements and crawl spaces. Grading is often required to
eliminate wet yards. Septic drainfields and infiltration trenches are
poorly suited because of the seasonal water table and slow permeability.
(54) Sassafras
This soil occurs on hilltops and sideslopes in sandy and clayey Coastal
Plain sediments. The upper five feet consists of predominantly sandy and
sandy clay loam materials. Depth to hard bedrock is greater than 200
feet. Permeability is moderate to moderately rapid. The soil typically
provides adequate support for small buildings (three stories or less) and
is suitable for most urban and residential uses.
(55) Glenelg
This soil occurs on hilltops and sideslopes underlain by micaceous
schist. Silts and clays overlie silty and sandy decomposed rock. Depth to
hard bedrock ranges from 5 to 100 feet. Permeability is moderate to
moderately rapid. Foundation support for small buildings (three stories
or less) is typically suitable. Because of a high mica content, the soil
tends to "fluff" up when disturbed and is difficult to compact,
requiring engineering designs for use as structural fill. This soil is
suitable for septic drainfields and infiltration trenches. Glenelg is
highly susceptible to erosion.
(56) Kempsville
This soil is found on hilltops in silty and sandy sediments of the
Coastal Plain. A discontinuous dense layer may occur within two to three
feet of the surface. Where present, this dense layer of slow permeability
results in a "perched" seasonal water table within two to three
feet of the surface. Depth to bedrock is greater than 40 feet. Building
support is typically favorable with proper drainage. Foundation drains
(exterior), waterproofing, and surface grading are needed to prevent wet
basements or crawl spaces. Grading and subsurface drainage may be
necessary to eliminate wet yards. Suitability for septic drainfields and
infiltration trenches is marginal because of slow permeability and the
perched water table.
(57) Brecknock loam
This sandy to sandy clay loam soil occurs on hilltops and sideslopes
underlain by gray baked sandstones. Depth to hard bedrock is 3 to 8 feet.
Soil permeability is moderate. Bedrock may restrict subsurface water
movement. Foundation support is generally good. Grading and subsurface
drainage may be needed to prevent wet yards. Suitability for septic
drainfields and infiltration trenches is marginal because of shallow
rock. Use of this bedrock in engineered fill, road embankment, or trench
backfill is limited due to rapid weathering. Added topsoil may be needed
in shallow areas to provide adequate rooting depth for lawns, trees, and
landscape plants.
(59) Orange
This plastic clay soil occurs on hilltops and sideslopes over greenstone
bedrock. A thin silty surface overlies a plastic clay subsoil. The
plastic clay, generally one to two feet thick often extends to bedrock in
gently sloping hilltop areas. A perched seasonal water table, resulting
from the slow permeability of the subsoil and underlying bedrock, is 0.5
to 1 foot below the surface. Depth to hard bedrock ranges from 4 to 15
feet. Building support is low in the soft plastic clays, but good on
bedrock. Foundation drains, grading, and waterproofing are necessary to
prevent wet basements and crawl spaces. Grading and subsurface drainage
may be needed to eliminate wet yards. Suitability for septic drainfields
and infiltration trenches is poor because of the plastic clays, perched
water table, and shallow depth to bedrock. Deep basements and excavations
may require blasting. Fibrous asbestos minerals may occur in the
greenstone bedrock3. These fibers may become airborne during excavation
and blasting operations. Worker protection and dust control measures are
required in such instances.
(60) Appling
This soil, derived from granite and gneiss, occurs on hilltops and
sideslopes. Silts and clays overlie clayey and sandy decomposed rock.
Sticky, plastic clays may occur within the subsoil. Depth to hard bedrock
ranges from 10 to 75 feet. Permeability is moderate to moderately slow in
the upper soil. Subsurface permeability is typically moderate to
moderately rapid, but may include relatively impermeable clay seams. The
soil typically provides favorable support for small buildings (3 stories
or less). The plastic subsoils are difficult to compact and move when
wet. Deep septic drainfields and infiltration trenches (>6 feet) may
be required because of slow subsoil permeability. Appling is highly
susceptible to erosion.
(61) Loamy and Gravelly Sediments
This soil unit is located primarily on steep hillsides in the Coastal
Plain. Soil materials include "bank run" gravels and sands mixed
with layers of silts and clays. Layers of plastic clays may be found in
areas where Marine Clays occur. The areas of this soil that are located
west of I-95 are generally stable except for a few isolated areas of
clays in terrace remnants that overlie weathered granite. Areas east of
I-95, especially in proximity to mapped areas of Marine Clay, should be
analyzed for foundation support and slope stability. Permeability, high
water table and drainage conditions are variable. Suitability for urban
and residential use is site-specific, depending on actual soil
conditions.
(62) Brecknock gravelly silt loam
This silty and silty clay soil occurs on hilltops and sideslopes
underlain by gray baked shales. Depth to hard bedrock is 3 to 8 feet.
Soil permeability is moderate. Bedrock may restrict subsurface water
movement. Foundation support is generally good. Grading and subsurface
drainage may be needed to prevent wet yards. Suitability for septic
drainfields and infiltration trenches is marginal because of possible
shallow rock. Use of this bedrock in engineered fill, road embankment, or
trench backfill is limited due to rapid weathering. Added topsoil may be
needed in shallow areas to provide adequate rooting depths for lawns,
trees, and landscape plants.
(63) Louisburg
This silty to sandy soil occurs on steep slopes underlain by granite and
gneiss. Depth to hard bedrock is typically from 4 to 50 feet.
Permeability is rapid. The soil provides good foundation support for
buildings. The shallow depth to hard rock (1 to 4 feet) in some places
decreases the potential suitability of these soils for septic drainfields
and infiltration trenches. Louisburg is highly susceptible to erosion.
(64) Silty and Clayey Sediments
This unit occurs primarily along steep hillsides and adjacent to
drainageways in the Coastal Plain. It consists predominantly of silty and
clayey strata, but may contain thin layers and lenses of sand, gravel and
Marine Clays. Soil properties are variable within this unit and low
bearing strata and perched seasonal high water tables may be present.
This unit may contain deposits of Marine Clay and should be analyzed for
potential shrink-swell and slope stability problems. Suitability for
septic drainfields and infiltration trenches is poor because of slow
permeability and potential plastic clay and slope instability problems.
(65) Colfax
The soil, derived from granite, gneiss and alluvium, occurs in
drainageways, footslopes, and upland flats. Sandy and loamy soils overlie
a dense clayey layer. This slowly permeable layer, 1.5 to 3 feet below
the surface, is usually 3 feet thick. Slowly permeable clayey soil
typically occurs below the compact layer. A perched seasonal water table,
above the dense layer, is 0.5 to 1.5 feet below the surface. Depth to
hard bedrock is from 6 to 25 feet. Foundation support may be marginal
because of soft soil and seasonal saturation. Foundation drains (interior
and exterior) and waterproofing are necessary to prevent wet basements.
Grading is needed to eliminate wet yards. Suitability for septic
drainfields and infiltration trenches is poor because of the seasonal
water table and slow permeability.
(66) Lloyd
This red soil occurs on hilltops underlain by schist and greenstone. A
loamy surface overlies a clayey subsoil. Depth to hard rock is from 4 to
30 feet. Permeability is moderate to moderately slow. The soil typically
provides adequate support for small buildings (three stories or less),
and is favorable for most urban and residential uses. Areas of greenstone
bedrock may contain naturally occurring fibrous asbestos minerals3. These
fibers may become airborne during excavation and blasting operations.
Worker protection and dust control measures are required in such
instances.
(67) Penn
This sandy and silty soil occurs on hilltops in weathered sandstone.
Hard bedrock is three to five feet below the surface. Permeability is
moderately rapid, but may be restricted by relatively un-fractured
bedrock in some areas. Foundation support is generally good. Grading and
subsurface drainage may be needed to prevent wet yards. Suitability for
septic drainfields and infiltration trenches may be limited in areas of
shallow bedrock. Use of this bedrock in engineered fill, road embankment,
or trench backfill is limited due to rapid disintegration. Additions of
topsoil may be needed in shallow areas to provide adequate rooting depths
for lawns, trees, and landscape plants.
(68) Roanoke
This soil occurs in clayey alluvium on low stream terraces in the
Piedmont Upland. The depth to seasonal high water table is from zero to
one foot. Depth to bedrock is 8 to 20 feet. Permeability is slow.
Flooding may occur following storm events1. Foundation support may be
poor because of soft soil and seasonal saturation. Basements below
original ground are not recommended because of severe wetness problems.
Suitability for septic drainfields and infiltration trenches is poor
because of wetness, slow permeability, and flooding potential. Roanoke is
a hydric soil and may contain potential nontidal wetlands.
(69) Enon
This soil occurs on hilltops and sideslopes over greenstone and schist.
The silty clay subsoil has moderate to high plasticity. A seasonal high
water table, over clay or bedrock, is 2 to 6 feet below the surface.
Depth to hard bedrock is typically 2 to 6 feet. Permeability is
moderately slow. Foundation support is poor in the clay subsoil, but good
on bedrock. Foundation drains and waterproofing are necessary to prevent
wet basements and crawl spaces. Grading and subsurface drainage may be
needed to eliminate wet yards. Septic drainfields and infiltration
trenches are poorly suited because of plastic clays, the high water
table, and shallow depth to bedrock. Deep basements and excavations may
require blasting. The greenstone bedrock may contain naturally occurring
fibrous asbestos minerals3. These fibers may become airborne during
excavation and blasting operations. Worker protection and dust control
measures are required in such instances.
(70) State
This sandy to silty soil occurs on high stream terraces in the Coastal
Plain. Flooding may occur following storm events1. The seasonal high
water table is four to six feet below the surface. Depth to hard bedrock
is 8 to 20 feet. Permeability is moderate. Foundation support is
typically good with proper drainage. Foundation drains and waterproofing
are needed to prevent wet basements. Grading may be required to eliminate
wet yards. Septic drainfields and infiltration trenches are marginally
suited because of the high water table and flooding potential.
(71) Bucks silt loam
This silty and clayey soil occurs on hilltops in weathered shale and
sandstone. Hard bedrock is three to eight feet below the surface.
Permeability is moderate, but may be restricted by un-fractured bedrock
in some areas. Foundation support is generally good. Grading and
subsurface drainage may be needed to prevent wet yards. Septic
drainfields and infiltration trenches may be limited in areas of shallow
bedrock. Use of this bedrock in engineered fill, road embankment, or
trench backfill is limited due to rapid disintegration.
(72) Bucks loam
This sandy and clayey soil occurs on hilltops in weathered sandstone.
Hard bedrock is three to eight feet below the surface. Permeability is
moderate, but may be restricted by un-fractured bedrock in some areas.
Foundation support is generally good. Grading and subsurface drainage may
be needed to prevent wet yards. Septic drainfields and infiltration
trenches may be limited in areas of shallow bedrock. Use of this bedrock
in engineered fill, road embankment, or trench backfill is limited due to
rapid disintegration.
(73) Penn silt loam
This silty soil occurs on hilltops and sideslopes over red sandstones
and shales. Depth to hard bedrock is less than three feet. Permeability
is moderate to moderately rapid, but may be restricted by un-fractured
bedrock. Foundation support is good. Grading and drainage may be needed
to prevent wet yards. Shallow bedrock may limit septic drainfields and
infiltration trenches. The bedrock disintegrates rapidly, limiting its
use in engineered fill, road embankment, or trench backfill. Topsoil may
be needed to increase rooting depths for lawns, trees, and landscape
plants.
(75) Penn loam
This loamy soil occurs on hilltops and sideslopes over red sandstones.
Depth to hard bedrock is less than two feet. Permeability is moderate,
but may be restricted by un-fractured bedrock. Foundation support is
good. Grading and drainage may be needed to prevent wet yards. Septic
drainfields and infiltration trenches are poorly suited because of
shallow bedrock. Use of this bedrock in engineered fill, road embankment,
or trench backfill is limited due to rapid disintegration. Topsoil may be
needed to increase rooting depths for lawns, trees, and landscape plants.
(76) Calverton loam
This silty to sandy clay soil occurs in drainageways and footslopes
underlain by sandstone. Slowly permeable subsoil clays have a medium
plasticity. The seasonal high water table is 0.5 to 2 feet below the
surface. Depth to hard bedrock is three to eight feet. Foundation support
may be poor because of soft plastic soil and seasonal saturation.
Basements below existing grade are not recommended because of potential
wetness problems. Engineered drainage is often needed to eliminate wet
yards. Septic drainfields and infiltration trenches are poorly suited
because of slow permeability, high water table, and shallow bedrock. The
bedrock disintegrates rapidly, limiting its use in engineered fill, road
embankment, and trench backfill.
(77) Penn shaly silt loam
This silty to clayey soil occurs on hilltops and sideslopes over shale.
Depth to hard bedrock is less than two feet. Permeability is moderate to
moderately rapid, but may be restricted by un-fractured bedrock.
Foundation support is good. Grading and drainage may be needed to prevent
wet yards. Septic drainfields and infiltration trenches are poorly suited
because of shallow bedrock. Use of this bedrock in engineered fill, road
embankment, or trench backfill is limited due to rapid disintegration.
Topsoil may be needed to increase rooting depths for lawns, trees, and
landscape plants.
(78) Calverton silt loam
This silty to clayey soil occurs in drainageways and footslopes
underlain by shale. Slowly permeable subsoil clays have a medium
plasticity. The seasonal high water table is 0.5 to 2 feet below the
surface. Depth to hard bedrock is three to eight feet. Foundation support
may be poor because of soft plastic soil and seasonal saturation.
Basements below existing grade are not recommended because of potential
wetness problems. Engineered drainage is often needed to eliminate wet
yards. Septic drainfields and infiltration trenches are poorly suited
because of slow permeability, high water table, and shallow bedrock. The
bedrock disintegrates rapidly, limiting its use in engineered fill, road
embankment, and trench backfill.
(79) Kelly
The silty and clayey soil occurs on hilltops and sideslopes underlain by
diabase and baked shales and sandstones. A thin plastic clay layer often
overlies bedrock. A seasonal high water table, one to two feet below the
surface occurs above clay or bedrock. Depth to bedrock is two to eight
feet. Permeability is moderately slow. Foundation support is good on
bedrock, but poor in the plastic subsoil. Foundation drains and
waterproofing are necessary to prevent wet basements. Grading and
subsurface drainage are needed to prevent wet yards. Septic drainfields
and infiltration trenches are poorly suited because of plastic clays,
high water table, and shallow bedrock. The bedrock disintegrates rapidly,
limiting its use in engineered fill, road embankment, and trench
backfill.
(80) Croton
This silty to clayey soil occurs in drainageways and footslopes
underlain by shale and sandstone. Subsoil clays have medium to high
plasticity. The seasonal high water table is 0 to 0.5 foot below the
surface. Depth to hard bedrock is from three to eight feet. Permeability
is moderately slow. Foundation support may be poor because of soft or
plastic subsoils and seasonal saturation. Basements below existing grade
are not recommended because of potential wetness problems. Grading and
subsurface drainage are often required to eliminate wet yards. Septic
drainfields and infiltration trenches are poorly suited because of slow
permeability, high water table, and shallow bedrock. The bedrock
disintegrates rapidly, limiting its use as engineered fill, road
embankment, and trench backfill. Croton is predominantly hydric and may
contain potential nontidal wetlands2.
(83) Galestown
This soil occurs on nearly level landscapes in the lower Coastal Plain.
Soil materials range from sandy loams to sands. Depth to bedrock is from
50 to 500 feet. Permeability is rapid. The soil provides adequate support
for small buildings (three stories or less), and is suitable for most
urban and residential uses.
(84) Fallsington
This sandy to sandy clay soil occurs on nearly level landscapes in the
Coastal Plain. Low areas along Dogue Creek are within the floodplain1.
Soft clay layers be included in the predominantly sandy soil. The
seasonal high water table is 0 to 0.5 foot below the surface.
Permeability is moderate to moderately rapid. Foundation support may be
poor because of seasonal saturation and soft soil. Basements below grade
are not recommended because of potential severe wetness problems.
Engineered drainage is often needed to eliminate wet yards. Suitability
for septic drainfields and infiltration trenches is poor because of
wetness and slow permeability. Fallsington is predominantly hydric and
may contain potential nontidal wetlands2.
(85) Elkton
This wet soil occurs on nearly level landscapes in the lower Coastal
Plain. Low areas of this soil, near larger streams, are within the
floodplain1. A silty surface overlies silty and clayey subsoils. Organic
strata (peat and muck) may be encountered in some areas. The clays
typically have a high shrink-swell potential that has resulted in
foundation damage on some existing residential dwellings. The seasonal
high water table is 0 to 0.5 foot below the surface. Depth to bedrock is
greater than 200 feet. Permeability is slow to very slow. Foundation
support may be poor because of soft soils, plastic clay, and seasonal
saturation. Basements below existing grade are not recommended because of
potential severe wetness problems. Engineered drainage designs are often
required to eliminate wet yards. Suitability for septic drainfields and
infiltration trenches is poor because of wetness and slow permeability.
Elkton is predominantly hydric and may contain potential nontidal
wetlands2.
(86) Klej
This soil occurs on nearly level landscapes in the lower Coastal Plain.
Soil materials are primarily sands and loamy sands. The seasonal high
water table is 1 to 2.5 feet below the surface. Depth to bedrock is
greater than 200 feet. Permeability is rapid. Foundation support may be
marginal because of soft soil and seasonal saturation. Foundation drains
and waterproofing are necessary to prevent wet basements and crawl
spaces. Grading and subsurface drainage may be needed to eliminate wet
yards. Suitability for septic drainfields and infiltration trenches is
poor because of the water table.
(87) Wickham
This soil occurs on low stream terraces in the Piedmont Upland and
Coastal Plain. Flooding may occur following storm events1. Silty and
clayey sediments are underlain with coarser textured materials. Depth to
bedrock is from 20 to 100 feet. Permeability is moderate to moderately
slow. Foundation support is typically adequate for small buildings (three
stories or less). Suitability for septic drainfields and infiltration
trenches may be marginal because of slow permeability.
(88) Hiwassee silt loam
This soil occurs on high stream terraces in the Piedmont Upland and
Coastal Plain. Flooding may occur following severe storm events1. Silty
and clayey sediments overlie typically coarser-textured materials. Depth
to bedrock is from 20 to 100 feet. Permeability is moderate to moderately
slow. Foundation support is typically adequate for small buildings (three
stories or less). Suitability for septic drainfields and infiltration
trenches may be marginal because of slow permeability.
(89) Tidal Marsh
Tidal marsh areas occur along the Potomac River and are periodically
inundated by flood waters under tidal influence4. The soils consist of
organic-rich, highly-stratified sandy, silty and clayey sediments.
Underlying soil is usually soft. Floodwater from tidal inundation are
typically shallow. Plant communities consist of sedges, cattails and
other hydrophytic plants.
(90) Augusta fine sandy loam
This predominantly sandy and silty soil occurs on stream terraces in the
Piedmont Upland and Coastal Plain. On low terraces along larger streams,
the soil may be subject to flooding1. A dense sandy clay subsurface
layer, 1 to 1.5 feet thick, is often found 1.5 feet below the surface. A
perched seasonal high water table occurs above the dense layer, one to
two feet below the surface. Depth to hard bedrock is from 10 to 60 feet.
Permeability is moderately slow. Foundation support may be marginal
because of soft soil and seasonal saturation. Foundation drains (exterior
and interior) and waterproofing are necessary to prevent wet basements.
Grading and subsurface drainage is required to eliminate wet yards.
Septic drainfields and infiltration trenches are poorly suited because of
slow permeability, perched water table, and potential flooding.
(91) Birdsboro
This soil, occurring on low terraces along Bull Run and Cub Run,
consists of predominantly silty and clayey alluvium. Low areas are within
the floodplain1. The seasonal high water table is two to four feet below
the surface. Depth to red shale or sandstone bedrock is generally from 7
to 20 feet, but may be within 2 feet in some places. Permeability is
moderately slow. Foundation support may be poor because of soft soil and
seasonal saturation. Foundation drains (exterior and interior) and
waterproofing are needed to prevent wet basements. Grading and subsurface
drainage are often required to eliminate wet yards. Suitability for
septic drainfields and infiltration trenches is poor due to the water
table and potential flooding. Use of the bedrock as engineered fill, road
embankment, or trench backfill is limited due to rapid disintegration.
(92) Raritan
This soil, occurring on low terraces along Bull Run and Cub Run,
consists of predominantly silty and clayey alluvium. Low areas are within
the floodplain1. The seasonal high water table is 0.5 to 3 feet below the
surface. Depth to red shale or sandstone bedrock is generally from 7 to
20 feet, but may be within 2 feet in some places. Permeability is
moderately slow. Foundation support may be poor because of soft soil and
seasonal saturation. Basements below existing grade are not recommended
because of potential severe wetness problems. Engineered drainage is
often required to eliminate wet yards. Suitability for septic drainfields
and infiltration trenches is poor due to the water table and potential
flooding. Use of the bedrock as engineered fill, road embankment, or
trench backfill is limited due to rapid disintegration.
(104) Catlett
This silty and gravelly soil occurs on hilltops and sideslopes underlain
by gray baked sandstone and shale. Hard bedrock is generally within two
feet of the surface. Soil permeability is moderate, but drainage may be
restricted by hard bedrock. Foundation support is generally good. Grading
and subsurface drainage may be needed to prevent wet yards. Suitability
for septic drainfields and infiltration trenches is poor because of
shallow bedrock. Use of this bedrock as engineered fill, road embankment,
or trench backfill is limited due to rapid weathering. Added topsoil may
be needed in shallow areas to provide adequate rooting depths for lawns,
trees, and landscape plants.
(110) Augusta loam
This predominantly silty soil occurs on stream terraces in the Piedmont
Upland and Coastal Plain. On low terraces along larger streams, the soil
may be subject to flooding1. A dense silty clay subsurface layer, 1 to
1.5 feet thick, is often found 1.5 feet below the surface. A perched
seasonal high water table occurs above the dense layer, one to two feet
below the surface. Depth to hard bedrock is from 10 to 60 feet.
Permeability is moderately slow. Foundation support may be marginal
because of soft soil and seasonal saturation. Foundation drains (exterior
and interior) and waterproofing are necessary to prevent wet basements.
Grading and subsurface drainage is required to eliminate wet yards.
Septic drainfields and infiltration trenches are poorly suited because of
slow permeability, perched water table, and potential flooding.
(112) Augusta sandy loam
This predominantly sandy and silty soil occurs on stream terraces in the
Piedmont Upland and Coastal Plain. On low terraces along larger streams,
the soil may be subject to flooding1. A dense sandy clay subsurface
layer, 1 to 1.5 feet thick, is often found 1.5 feet below the surface. A
perched seasonal high water table occurs above the dense layer, one to
two feet below the surface. Depth to hard bedrock is from 10 to 60 feet.
Permeability is moderately slow. Foundation support may be marginal
because of soft soil and seasonal saturation. Foundation drains (exterior
and interior) and waterproofing are necessary to prevent wet basements.
Grading and subsurface drainage is required to eliminate wet yards.
Septic drainfields and infiltration trenches are poorly suited because of
slow permeability, perched water table, and potential flooding.
(113) Fairfax gravelly silt
loam
This upland soil consists of silty and gravelly old alluvium, typically
3 to 7 feet thick, overlying silty and sandy decomposed rock. A
discontinuous dense layer results in a "perched" seasonal water
table at 1.5 to 2.5 feet below the surface. Depth to rock is from 10 to
100 feet. Permeability is moderately slow in the dense layer and moderate
in the underlying soils. With adequate engineered drainage, the soil
typically provides adequate support for small buildings (3 stories or
less). Exterior foundation drains and waterproofing are necessary to
prevent wet basements and crawl spaces. Surface grading and subsurface
drains may be needed to eliminate wet yards. Suitability for septic
drainfields and infiltration trenches is marginal because of slow
permeability and the perched water table.
(114) Masada fine sandy loam
Masada is found on high terraces, formed in loamy and gravelly material
washed from soils of the Piedmont Upland. The sticky, plastic clay
subsoil may restrict drainage and be difficult to manipulate for
engineering purposes when wet. Depth to hard bedrock ranges from 30 to
150 feet. Permeability is moderately slow in the subsoil. Foundation
support is typically good. Exterior foundation drains and waterproofing
are needed to prevent wet basements. Grading and subsurface drainage are
often required to eliminate wet yards. Suitability for septic drainfields
and infiltration trenches is marginal because of slow permeability.
(115) Hiwassee fine sandy loam
This soil occurs on high stream terraces in the Piedmont Upland and
Coastal Plain. Flooding may occur following severe storm events1. Fine
sandy, silty and clayey sediments are underlain with coarser textured
materials. Depth to bedrock is from 20 to 100 feet. Permeability is
moderate to moderately slow. Foundation support is typically adequate for
small buildings (three stories or less). Suitability for septic
drainfields and infiltration trenches may be marginal because of slow
permeability.
(116) Christiana
This soil occurs on hilltops and sideslopes in the Coastal Plain. Red
plastic clays and silty clays may contain thin sandy strata. Depth to
bedrock is greater than 30 feet. Subsurface permeability is moderately
slow to slow, often resulting in a perched water table at variable
depths. Foundation support is marginal because of the plastic clays.
Foundation drains and waterproofing are necessary to prevent wet
basements. Grading and subsurface drainage are often necessary to
eliminate wet yards. Septic drainfields and infiltration trenches are
poorly suited because of the clay and slow permeability. Christiana is
similar to the Marine Clays.
(117) Fresh Water Marsh
This soil occurs in low, flat areas in the Coastal Plain and is
periodically wet, inundated, or partially submerged by fresh water.
Flooding may occur following storm events1. An organic surface covers
highly variable, stratified sandy, silty and clayey sediments. The
seasonal high water table may be at or above the surface for extended
periods of time. Permeability is generally low. Foundation support is
poor because of soft and very soft soil and seasonal saturation.
Basements below existing grade are not recommended because of potential
severe wetness problems. Septic drainfields and infiltration trenches are
poorly suited because of wetness and potential flooding. Sedges, cattails
and other hydrophytic plants are predominant. Fresh water marshes are
largely wetland areas2.
(118) Marine Clay
This unit occurs on hilltops and sideslopes in the Coastal Plain. Highly
plastic silts and clays of variable thickness underlie surface silts to
gravels a few inches to a few feet thick. The clay deposits consist of
highly fractured and broken clays and silty clays which have a high
shrink-swell potential. The depth of the seasonal high water table is
variable depending on soil stratification, landscape position, and local
hydrologic features such as seepage areas. Water is often perched above
slowly permeable subsurface strata. Depth to hard bedrock is generally
greater than 50 feet. Slope instability and poor foundation support are
major problems requiring intensive geotechnical analysis. Numerous
structures have sustained damage from inadequate construction practices.
Septic drainfields and infiltration trenches are poorly suited because of
plastic clays, perched water table, and unstable slopes.
(120) Altavista
This clayey soil occurs on low stream terraces in the Coastal Plain.
Flooding may occur following storm events1. The clayey subsoil restricts
drainage, resulting in a perched seasonal high water table within two to
three feet of the surface. Depth to hard bedrock is 10 to 40 feet.
Permeability is moderately slow. Foundation support is typically good
with proper drainage. Foundation drains and waterproofing are needed to
prevent wet basements. Grading and subsurface drainage are often required
to eliminate wet yards. Suitability for septic drainfields and
infiltration trenches is poor because of the water table, slow
permeability, and potential flooding.
(128, 129) Montalto stony/rocky silt
loam
This upland soil consists of a silty surface and a clayey subsoil
underlain by a diorite/diabase bedrock. Surface stones and occasional
rock outcrops may be present. Depth to bedrock ranges from two to six
feet. Permeability is moderate. These soils generally occur in
association with the highly plastic Iredell soils. Montalto soils have a
lower plasticity than Iredell, and are generally suitable for building
support. Suitability for septic drainfields and infiltration trenches is
marginal to poor because of the shallow depth to rock.
(132) Mayodan
This soil occurs on hilltops and sideslopes along the eastern edge of
the Triassic Basin. Bedrock consists of relatively thin deposits (2 to 10
feet) of sandstone conglomerates mixed with schist materials. The loamy
surface and silty clay to clay subsurface contains rounded and angular
gravel. Depth to rock is from 10 to 15 feet. A moderately slow to slow
subsoil permeability may result in saturated surface soils and a perched
seasonal water table for short duration following rainfall events.
Foundation support for small buildings (3 stories or less) is generally
favorable. Exterior foundation drains and waterproofing are necessary to
prevent wet basements and crawl spaces. Grading and subsurface drains may
be needed to eliminate wet yards. Shallow bedrock in some areas may limit
the suitability for septic drainfields and infiltration trenches.
(141) Rocky Land - (Orange)
This mapping unit occurs on hilltops and sideslopes in association with
the Orange soils in the greenstone areas. Frequent rock outcrops or
boulders cover 20 to 50 percent of the surface. Plastic clay subsoils may
occur at one to three feet. The depth to hard bedrock varies from zero to
15 feet. The depth to seasonal high water table varies from one to
greater than ten feet. Foundation support is good on bedrock, but may be
poor in areas with plastic clay subsoil. Suitability for septic
drainfields and infiltration trenches is poor because of plastic clays
and shallow depth to rock. The shallow bedrock and stoniness make these
soils difficult to excavate and grade. Blasting in the hard bedrock may
be required for below grade basements and excavations. The greenstone
bedrock may contain naturally occurring fibrous asbestos minerals3. These
fibers may become airborne during excavation and blasting operations.
Worker protection and dust control measures are required in such
instances.
(142) Very Rocky Land -
(Orange)
This mapping unit occurs on hilltops and sideslopes in association with
the Orange soils in the greenstone areas. Frequent rock outcrops or
boulders cover over 50 percent of the surface. Plastic clay subsoils may
occur at one to three feet. The depth to hard bedrock varies from zero to
15 feet. The depth to seasonal high water table varies from one to
greater than ten feet. Foundation support is good on bedrock, but may be
poor in areas with plastic clay subsoil. Suitability for septic
drainfields and infiltration trenches is poor because of plastic clays
and shallow depth to rock. The shallow bedrock and stoniness make these
soils difficult to excavate and grade. Blasting in the hard bedrock may
be required for below grade basements and excavations. The greenstone
bedrock may contain naturally occurring fibrous asbestos minerals3. These
fibers may become airborne during excavation and blasting operations.
Worker protection and dust control measures are required in such
instances.
(148) Iredell-Mecklenburg
This highly plastic soil occurs on hilltops and sideslopes, formed in
weathered diabase materials. A silty surface overlies a sticky plastic
clay subsoil one to three feet thick. Sandy clays and clayey sands occur
below the clay layer. A perched seasonal high water table, above the
clays, is one to two feet below the surface. Depth to hard bedrock is
usually from 3 to 15 feet. Permeability is slow. Foundation footings must
extend below the soft plastic clays, generally to bedrock, to ensure
competent building support. Foundation drains, surface grading, and
waterproofing are necessary to prevent wet basements and crawl spaces.
Surface grading and subsurface drainage may be needed to eliminate wet
yards. Suitability for septic drainfields and infiltration trenches is
poor because of the plastic clays, perched water table, and shallow depth
to bedrock. Deep basements and excavations may require blasting in hard
bedrock.
(149) Lunt
The Lunt series is an extremely variable unit found on hilltops and
sideslopes in sands, silts, and clays of the Coastal Plain. A silty
surface overlies plastic silty and clayey subsoils. The subsoil is slowly
permeable, resulting in a perched seasonal water table. Depth the hard
bedrock is typically greater than 75 feet. The 149 unit, usually in close
proximity to areas of the Marine Clay, should be analyzed for foundation
support and slope stability. Foundation drains, surface grading, and
waterproofing are necessary to prevent wet basements and crawl spaces.
Suitability for septic drainfields and infiltration trenches is poor
because of the slowly permeable clays and potential slope instability.
(152) Elbert - (Orange Group)
This wet, plastic soil occurs in drainageways and footslopes in
materials derived from weathered greenstone and alluvium. Slowly
permeable plastic clay subsoils occur 2 to 4 feet below the surface. The
seasonal high water table is 0 to 0.5 foot below the surface. The depth
to bedrock varies from 3 to 15 feet. Foundation footings must extend
below the soft plastic clays, generally to bedrock, to ensure competent
building support. Basements below existing grade are not recommended
because of potential severe wetness problems. Engineered drainage designs
are often required to eliminate wet yards. Septic drainfields and
infiltration trenches are poorly suited because of wetness, plastic clays
and shallow depth to bedrock. Elbert is predominantly hydric and may
contain potential nontidal wetlands2. The greenstone bedrock may contain
naturally occurring fibrous asbestos minerals3. These fibers may become
airborne during excavation and blasting operations. Worker protection and
dust control measures are required in such instances.
(232) Fairfax loam
This upland soil consists of silty, clayey and gravelly old alluvium,
typically 3 to 7 feet thick, overlying silty and sandy decomposed rock. A
discontinuous dense layer results in a "perched" seasonal water
table at 1.5 to 2.5 feet below the surface. Depth to rock is from 10 to
100 feet. Permeability is moderately slow in the subsurface. Building
support may be marginal because of soft soil and seasonal saturation.
Foundation drains (interior and exterior) and waterproofing are necessary
to prevent wet basements and crawl spaces. Surface grading and subsurface
drains may be needed to eliminate wet yards. Suitability for septic
drainfields and infiltration trenches is marginal to poor because of slow
permeability and the perched water table.
(273) Readington
This silty and clayey soil occurs on nearly level uplands underlain by
red shale and sandstone. The seasonal high water table, perched above
bedrock, is 0.5 to 2 feet below the surface. The depth to bedrock is from
two to three feet. Soil permeability is moderate, but the shallow bedrock
has few fractures to allow water to pass through. Foundations typically
extend to shallow rock. Foundation drains and waterproofing are necessary
to prevent wet basements. Grading and subsurface drainage are often
required to eliminate wet yards. Suitability for septic drainfields and
infiltration trenches is poor because of shallow bedrock and the perched
water table. Use of this bedrock as engineered fill, road embankment,
and/or trench backfill is limited due to rapid disintegration. Added
topsoil may be needed to provide adequate rooting depths for lawns,
trees, and landscape plants.