SoilsPart 6 -Facility Description -Basin 1 - Wetaond and Infiltration Pond
Total Area Tributary to Facility Including Off-site (acres):........ 2.23 ac
Total On-site Area Tributary to Facility (acres) :................ 1.47 ac
Design Impervious Area Tributary to Facility (acres) :............ 1.51ac
Design Landscaped Area Tributary to Facility (acres):........... 0.72 ac
Design Total Tributary Area to Facility (acres) :................ 2.23 ac
Enter a one (1) for the type of facility: ) :..................... .
Wet pond detention .................................. 1
Wet pond water surface volume, cf ........... ......... 12,152
Dry pond detention ................................ .
Underground detention ............................. .
Infiltration pond .................................... 1
Dry well infiltration ...................................
Coalescing plate separator ............................
Centrifuge separator ............................... .
Biofilter ...........................................
Other ..............................
Outlet type (Enter a one (1) for each type present)
Filter .............................................
Oil water separator ................................. .
Single orifice ...................................... .
Multiple orifice ..................................... .
Weir .............................................
Spillway .......................................... 1
Pump(s) ..........................................
Other .............................................
Part 7 -Release to Groundwater
Design Percolation Rate to Groundwater (if applicable) ............... 20 inch/hour
Part 8 -Release to Surface Water N/A
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Thurston County, Washington
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TABLE 16.--WATER FEATURES--Continued
Soil name and ;Hydrologic;
~Y''
water
~'= map symbol ,
,
, group ; Frequency ; Duration ,
~ i i
, , i Months ;
i
i Depth ~ Kind
,
,
Ft
,
-`: 100, 101------- ; D ',None------------, --- i --- i 0.5-1.5 ;Perched
f Scamman ;
, , i i
i , ,
,
,
,
102, 103----------------;
B , , ,
;None------------; --- ; ,
--- ;
>6.0 ,
; ---
Schneider
~ i
' '
104---------------------,
C i
' ' '
,Rare------------, --- ,
'
--- ,
1 5-3 0
'A arent
, PP
Semiahmoo , , i i
105---------------------; D ;None------- ; --- ; --- i iAPParent
Shalcar
106---------------------i D ;Occasional------;Long----------; Nov-May ; +1-0 ;Apparent
Shalcar Variant
,
,
,
` 107, 108----------------;
D ,
,
, , ,
;None------------; --- ; ,
,
--- ;
1.0-2.0 ,
,
;Perched
Skipopa
i
, , ,
,
,
109----------------- ; D ;None------------; --- ; --- ; 1.0-3.0 ;Apparent
I
Sparta i
i
,
, , , ,
i , i ,
i ,
,
110, 111, 112, 113------; B ;None------------; --- ; --- ; >6.0 ; ---
Spanaway
114*:
Spanaway---------------, B ,None------------; --- ; --- , >6.0 ~ ---
, , , , , ,
Nisqually--------------; B ;None------------; --- ; --- ; >6.0 ; ---
,
115---------------------i
C , , ,
;Occasional------;Brief---------; ,
Nov-Apr ;
2.0-4.0 ,
;Apparent
Sultan
,
116-------------- ;
D , , ,
;Frequent--------;Brief---------; ,
Nov-Jun ;
+1-0 ,
;Apparent
Tacoma
,
, , , ,
, , i ,
i ,
,
117, 118, 119-----------; C ;None------------; --- ~ --- , >6.0 ; ---
Tenino ; ~
, , , , , ,
120------------ , D ,Rare-------- , --- , --- , 0-1.0 ,Apparent
Tisch
,
I , , , ,
, i , ,
121, 122----------------{
B ,
;None------------~ --- ~ ,
--- ~
>6.0 ,
, ---
Vailton
, i , , , ,
123, 124----------------~ B ;None------------~ --- , --- ~ >6.0 ~ ---
Wilkeson ~ i i
125------------- ,
--------'
C
,Rare------------
' i --- ~ --- ~ >2.0 ,Apparent
Xerorthents
126, 127, 128-----------i C ;None------------; --- ; --- ; 1.5-3.0 ;Apparent
Yelm
,
,
, , ,
, , , i
i ,
,
277
e
Months
Nov-Mar
Nov-May
Oct-May
Oct-May
Nov-May
Nov-Apr
,
,
,
,
,
, ---
,
,
, _
, - -
,
,
Nov-Apr
,
,
,
,
Nov-Jun
Dec-Apr
Nov-Mar
Dec-Mar
* See description of the map unit for composition and behavior characteristics of the map unit.
Thurston County, Washington
Included areas make up about 10 percent of the total
acreage.
Permeability is moderately rapid in the Spana soil.
Available water capacity is moderate. Effective rooting
depth is 20 to 40 inches. A seasonal high water table is
at a depth of about 12 to 36 inches from November to
April. Runoff is slow, and the hazard of water erosion is
slight.
Most areas are used as hayland and pasture. This
unit is suited to hay and pasture. The main limitations
are the seasonal high water table and the moderate
available water capacity. Proper stocking rates, pasture
rotation, and restricted grazing during wet periods help
to keep the pasture in good condition and protect the
soil from erosion. Rotation grazing helps to maintain the
quality of forage. Periodic mowing helps to maintain
uniform growth, discourages selective grazing, and
controls weeds. In most years irrigation is needed for
maximum production. Sprinkler irrigation is the best
method of applying water. The amount of water applied
should be sufficient to wet the root zone but small
enough to minimize the leaching of plant nutrients.
A few areas are used as woodland. On the basis of a
100-year site curve, the estimated site index for
Douglas-fir is 144. On the basis of a 50-year site curve,
it is 110. The estimated growth rate of an unmanaged,
even-aged stand of Douglas-fir is 150 cubic feet per
acre per year at 60 years of age.
The main limitation affecting the harvesting of timber
is the muddiness caused by seasonal wetness. Use of
wheeled and tracked equipment when the soil is wet
results in ruts and soil compaction. Unsurfaced roads
and skid trails are soft and can be impassable when
wet. Logging roads require suitable surfacing material
for year-round use. Rounded pebbles and cobbles for
road construction are readily available on this unit. The
seasonal high water table limits the use of equipment to
dry periods. Disturbance of the protective layer of duff
can be minimized by the careful use of wheeled and
tracked equipment.
Seedling establishment is the main concern in the
production of timber. Reforestation can be
accomplished by planting Douglas-fir seedlings. If the
stand includes seed trees, natural reforestation by red
alder occurs periodically in cutover areas. The seasonal
high water table inhibits root respiration and thus results
in some seedling mortality. When openings are made in
the canopy, invading brushy plants can prevent the
establishment of planted Douglas-fir seedlings.
Common forest understory plants are cascade
Oregon-grape, salal, vine maple, western brackenfern,
and Oregon white oak.
89
This map unit is in capability subclass Illw.
110-Spanaway gravelly sandy loam, 0 to 3
percent slopes. This very deep, somewhat excessively
drained soil is on terraces. It formed in glacial outwash
and volcanic ash. The native vegetation is mainly
grasses, ferns, and a few conifers. Elevation is 100 to
400 feet. The average annual precipitation is 45 to 55
inches, the average annual air temperature is about 51
degrees F, and the average frost-free period is 150 to
200 days.
Typically, the surface layer is black gravelly sandy
loam about 15 inches thick. The subsoil is dark
yellowish brown very gravelly loam about 5 inches thick,
The substratum to a depth of 60 inches or more is dark
yellowish brown extremely gravelly sand.
Included in this unit are small areas of Alderwood
soils on till plains; Everett, Indianola, and Nisqually soils
on outwash terraces; and Spana soils in depressions.
Also included are small areas of Spanaway soils that
have a stony sandy loam surface layer and small areas
of Spanaway gravelly sandy loam that have slopes of 3
to 15 percent. Included areas make up about 20
percent of the total acreage.
Permeability is moderately rapid in the subsoil of the
Spanaway soil and very rapid in the substratum.
Available water capacity is low. Effective rooting depth
is 60 inches or more. Runoff is slow, and the hazard of
water erosion is slight.
This unit is used mainly as hayland, pasture, or
cropland, as a site for homes, or as a source of gravel.
It is also used as woodland.
The main limitation affecting hay and pasture is the
low available water capacity. Proper grazing practices,
weed control, and fertilizer are needed to ensure
maximum quality of forage. Rotation grazing helps to
maintain the quality of forage. Periodic mowing helps to
maintain uniform growth, discourages selective grazing,
and controls weeds. Animal manure can be applied
periodically during the growing season. Areas that
receive heavy applications should be harrowed at least
once a year. In summer, irrigation is needed for
maximum production of most forage crops. Sprinkler
irrigation is the best method of applying water. The
amount of water applied should be sufficient to wet the
root zone but small enough to minimize the leaching of
plant nutrients.
This unit is suited to crops. Wheat, oats,
strawberries, raspberries, blackberries, and sweet corn
are commonly grown. The main limitation is the low
available water capacity. In summer, irrigation is
needed for maximum production of most crops.
90
Sprinklers can be used, but a slow application rate is
needed to minimize runoff. The amount of water applied
should be sufficient to wet the root zone but small
enough to minimize the teaching of plant nutrients. The
application rate should be adjusted to the available
water capacity, the water intake rate, and the needs of
the crop. Animal manure can be applied periodically
during the growing season, Areas that receive heavy
applications should be harrowed at least once a year.
This unit is well suited to homesites. Pebbles and
cobbles should be removed, particularly in areas used
for lawns. In summer, irrigation is needed for lawn
grasses, shrubs, vines, shade trees, and ornamental
trees. Mulch, fertilizer, and irrigation are needed to
establish lawn grasses and other small-seeded plants.
The main limitation affecting septic tank absorption
fields is a poor filtering capacity. If the density of
housing is moderate or high, community sewage
systems are needed to prevent the contamination of
water supplies caused by seepage from onsite sewage
disposal systems. Cutbanks are not stable and are
subject to sloughing.
Douglas-fir is the main woodland species on this unit.
Among the trees of limited extent are Oregon white oak,
lodgepole pine, and red alder. Douglas-fir and Scotch
pine are grown on Christmas tree plantations. On the
basis of a 100-year site curve, the mean site index for
Douglas-fir is 140. On the basis of a 50-year site curve,
it is 108. The highest average growth rate of an
unmanaged, even-aged stand of Douglas-fir is 145
cubic feet per acre per year at 65 years of age.
This soil is suited to year-round logging. Unsurfaced
roads and skid trails are slippery when wet. Logging
roads require suitable surfacing material for year-round
use. Rounded pebbles and cobbles for road
construction are readily available on this unit.
Disturbance of the protective layer of duff can be
minimized by the careful use of wheeled and tracked
equipment.
Seedling establishment and seedling mortality are the
main concerns in the production of timber. Reforestation
can be accomplished by planting Douglas-fir seedlings.
If the stand includes seed trees, natural reforestation by
Douglas-fir, Oregon white oak, and lodgepole pine
occurs periodically in cutover areas. Droughtiness in the
surface layer reduces the seedling survival rate. When
openings are made in the canopy, invading brushy
plants can delay the establishment of planted Douglas-
fir seedlings.
Common forest understory plants are cascade
Oregon-grape, salal, western brackenfern, western
swordfern, Indian plum, and Scotch-broom.
Soil Survey
This map unit is in capability subclass IVs.
111-Spanaway gravelly sandy loam, 3 to 15
percent slopes. This very deep, somewhat excessively
drained soil is on terraces. It formed in glacial outwash
and volcanic ash. The native vegetation is mainly
grasses, ferns, and a few conifers. Elevation is 100 to
400 feet. The average annual precipitation is 45 to 55
inches, the average annual air temperature is about 51
degrees F, and the average frost-free period is 150 to
200 days.
Typically, the surface layer is black gravelly sandy
loam about 15 inches thick. The subsoil is dark
yellowish brown very gravelly sandy loam about 5
inches thick. The substratum to a depth of 60 inches or
more is dark yellowish brown extremely gravelly sand.
Included in this unit are small areas of Alderwood
soils on till plains and Eve~reft, Indianola, and Nisqually
soils on terraces. Also included are small areas of
Spanaway soils that have a stony sandy loam surface
layer and small areas of Spanaway gravelly sandy loam
that have slopes of 0 to 3 percent. Included areas make
up about 20 percent of the total acreage.
Permeability is moderately rapid in the subsoil of the
Spanaway soil and very rapid in the substratum.
Available water capacity is low. Effective rooting depth
is 60 inches or more. Runoff is slow, and the hazard of
water erosion is slight.
This unit is used mainly as hayland or pasture, as a
site for homes, or as a source of gravel. It is also used
as woodland.
The main limitation affecting hay and pasture is the
low available water capacity during the growing season.
Proper grazing practices, weed control, and fertilizer are
needed to ensure maximum quality of forage. Rotation
grazing helps to maintain the quality of forage. Periodic
mowing helps to maintain uniform growth, discourages
selective grazing, and controls weeds. Animal manure
can be applied periodically during the growing season.
Areas that receive heavy applications should be
harrowed at least once a year. In summer, irrigation is
needed for maximum production of most forage crops.
Sprinkler irrigation is the best method of applying water. '
The amount. of water applied should be sufficient to wet
the root zone but small enough to minimize the leaching
of plant nutrients.
This unit is suited to homesites. The main limitation
is the slope. Cutbanks are not stable and are subject to
sloughing. A plant cover can be es#ablished and
maintained through proper fertilizing, seeding, mulching,
and shaping of the slopes. Pebbles and cobbles should
be removed, particularly in areas used for lawns. In
Thurston County, Washington
summer, irrigation is needed for lawn grasses, shrubs,
vines, shade trees, and ornamental trees. Mulch,
fertilizer, and irrigation are needed to establish lawn
grasses and other small-seeded plants. Topsoil can be
stockpiled and used to reclaim areas disturbed during
construction.
.The main limitation affecting septic tank absorption
fields is a poor filtering capacity in the substratum. If the
density of housing is moderate or high, community
sewage systems are needed to prevent the
contamination of water supplies caused by seepage
from onsite sewage disposal systems. The slope
hinders the installation of the absorption fields.
Absorption lines should be installed on the contour.
Douglas-fir is the main woodland species on this unit.
Among the trees of limited extent are Oregon white oak,
lodgepole pine, and red alder. Douglas-fir and Scotch
pine are grown on Christmas tree plantations. On the
basis of a 100-year site curve, the mean site index for
Douglas-fir is 140. On the basis of a 50-year site curve,
it is 108. The highest average growth rate of an
unmanaged, even-aged stand of Douglas-fir is 145
cubic feet per acre per year at 65 years of age.
This soil is suited to year-round logging. Unsurfaced
roads and skid trails are slippery when wet. Logging
roads require suitable surfacing material for year-round
use. Rounded pebbles and cobbles for road
construction are readily available on this unit.
Disturbance of the protective. layer of duff can be
minimized by the careful use of wheeled and tracked
equipment.
Seedling establishment and seedling mortality are the
main concerns in the production of timber. Reforestation
can be accomplished by planting Douglas-fir seedlings.
If the stand includes seed trees, natural reforestation of
cutover areas by Oregon white oak and lodgepole pine
occurs infrequently. Droughtiness in the surface layer
reduces the seedling survival rate. When openings are
made in the canopy, invading brushy plants can delay
the establishment of planted Douglas-fir seedlings.
Common forest understory plants are cascade
Oregon-grape, salal, western brackenfern, western
swordfern, Indian plum, and Scotch-broom.
This map unit is in capability subclass IVs.
112-Spanaway stony sandy loam, 0 to 3 percent
slopes. This very deep, somewhat excessively drained
soil is on terraces. It formed in glacial outwash and
volcanic ash. The native vegetation is mainly grasses,
ferns, and a few conifers. Elevation is 200 to 400 feet.
The average annual precipitation is 40 to 50 inches, the
average annual air temperature is about 51 degrees F,
91
and the average frost-free period is 150 to 200 days.
Typically, the surface layer is black stony sandy loam
about 16 inches thick. The subsoil is very dark brown
gravelly sandy loam about 6 inches thick. The
substratum to a depth of 60 inches or more is grayish
brown extremely gravelly sand.
Included in this unit are small areas of Alderwood
soils on till plains, Baldhill soils on terminal moraines,
and Everett, Indianola, and Nisqually soils on terraces.
Also included are small areas of Spanaway soils that
have a gravelly sandy loam surface layer and small
areas of Spanaway stony sandy loam that have slopes
of 3 to 15 percent, Included areas make up about 15
percent of the total acreage.
Permeability is moderately rapid in the subsoil of the
Spanaway soil and very rapid in the substratum.
Available water capacity is low. Effective rooting depth
is 60 inches or more. Runoff is slow, and the hazard of
water erosion is slight.
This unit is used mainly for hayland, pasture, or
homesites. The main limitations affecting hay and
pasture are the low available water capacity and the
stones on the surface. Proper grazing practices, weed
control, and fertilizer are needed to ensure maximum
quality of forage. Rotation grazing helps to maintain the
quality of the forage. Because of the surface stones,
spreading animal manure, mowing, and seeding are
difficult. In summer, irrigation is needed for maximum
production of most forage crops. Sprinkler irrigation is
the best method of applying water. The amount of water
applied should be sufficient to wet the root zone but
small enough to minimize the leaching of plant
nutrients.
This unit is well suited to homesites. Pebbles,
cobbles, and stones should be removed, particularly in
areas used for lawns. In summer, irrigation is needed
for lawn grasses, shrubs, vines, shade trees, and
ornamental trees. Mulch, fertilizer, and irrigation are
needed to establish lawn grasses and other small-
seeded plants. Cutbanks are not stable and are subject
to sloughing.
The main limitation affecting septic tank absorption
fields is a poor filtering capacity in the substratum. If the
density of housing is moderate or high, community
sewage systems are needed to prevent the
contamination of water supplies caused by seepage
from onsite sewage disposal systems.
This map unit is in capability subclass IVs.
113-Spanaway stony sandy loam, 3 to 15 percent
slopes. This very deep, somewhat excessively drained
soil is on terraces. It formed in glacial outwash and
158
Spanaway Series
The Spanaway series consists of very deep,
somewhat excessively drained soils on terraces. These
soils formed in glacial outwash and volcanic ash. Slope
is 0 to 15 percent. Elevation is 100 to 400 feet. The
average annual precipitation is 40 to 55 inches, the
average annual air temperature is about 51 degrees F,
and the average frost-free season is 150 to 200 days.
These soils are sandy-skeletal, mixed, mesic Andic
Xerumbrepts.
Typical pedon of Spanaway gravelly sandy loam, 0 to
3 percent slopes, 4 miles southeast of Lacey; about 250
feet west and 400 feet south of the northeast corner of
sec. 25, T. 36 N.. R. 1 W.
A-0 to 15 inches; black (10YR 2/1 j gravelly sandy
loam, very dark grayish brown (10YR 3/2) dry; weak
fine granular structure; loose, very friable, nonsticky
and nonplastic: many fine, medium, and coarse
roots; 25 percent pebbles; strongly acid; clear
smooth boundary.
Bw-15 to 20 inches; dark yellowish brown (10YR 3/4)
very gravelly sandy loam, light olive brown (2.5Y
5!4) dry; weak fine subangular blocky structure;
loose, very friable, nonsticky and nonplastic; many
fine, medium, and coarse roots; 55 percent pebbles;
medium acid; clear smooth boundary.
C-20 to 60 inches; dark yellowish brown (10YR 4/4)
extremely gravelly sand, yellowish brown (10YR
5/4) dry; single grained; loose; few fine roots; 80
percent pebbles, 10 percent cobbles; slightly acid.
The thickness of the solum ranges from 15 to 25
inches. The content of coarse fragments in the control
section ranges from 5Q to 85 percent, The weighted
average texture of this section is very gravelly sand or
extremely gravelly sand. The umbric epipedon is 10 to
20 inches thick.
The A horizon has hue of 10YR or 7.5YR, value of 3
or 4 when dry, and chroma of 1 or 2 when moist or dry
It is medium acid or strongly acid. The Bw horizon has
value of 4 or 5 when dry and 3 or 4 when moist. It is
very gravelly sandy loam, very gravelly loam, or
extremely gravelly sandy loam. The C horizon has hue
of 10YR or 2.5Y, value of 5 or 6 when dry and 4 or 5
when moist, and chroma of 3 or 4 when dry or moist. It
is extremely gravelly sand or extremely gravelly loamy
sand and is slightly acid or neutral.
Sultan Series
The Sultan series consists of very deep, moderately
Soil Survey
well drained soils on flood plains. These soils formed in
alluvium. Slope is 0 to 3 percent. Elevation is 20 to 75
feet. The average annual precipitation is 40 to 50
inches, the average annual air temperature is about 50
degrees F, and the average frost-free season is 150 to
200 days.
These soils are fine-silty, mixed, nonacid, mesic
Aquic Xerofluvents.
Typical pedon of Sultan silt loam, 7 miles east of
Lacey; about 1,000 feet east and 1,975 feet north of the
southwest corner of sec. 16, T. 18 N., R. 1 E.
Ap-0 to 7 inches; dark yellowish brown (10YR 3/4) silt
loam, brown (10YR 5/3) dry; moderate fine and
medium granular structure; slightly hard, very
friable, slightly sticky and slightly plastic; many fine,
medium, and coarse roots; many very fine and fine
tubular pores; slightly acid; abrupt smooth
boundary,
BA-7 to 20 inches; dark yellowish brown (10YR 4/4)
silt loam, brown (10YR 5/3) dry; moderate fine and
medium subangular blocky structure; slightly hard,
very friable, slightly sticky and slightly plastic; many
very fine, fine, and medium roots; many very fine
and fine tubular pores; slightly acid; clear wavy
boundary.
Bw1-20 to 25 inches; dark brown (10YR 3/3) silt loam,
grayish brown (2.5Y 5/2) dry; common fine
prominent red (2.5YR 5/8) mottles; moderate fine
and medium subangular blocky structure; slightly
hard, very friable, slightly sticky and slightly plastic;
common fine and medium roots; common very fine
and fine tubular pores; slightly acid; gradual wavy
boundary.
Bw2-25 to 45 inches; dark brawn (10YR 4/3) silt loam,
light brownish gray (10YR 6/2) dry; common
medium prominent red (2.5YR 5/8) mottles;
moderate medium and coarse subangular blocky
structure; slightly hard, very firiable, slightly sticky
and slightly plastic; few very fine and fine roots; few
very fine and fine tubular pores; slightly acid;
gradual wavy boundary.
C-45 to 60 inches; grayish brown (10YR 5/2) silt loam,
light gray (10YR 7/2) dry; common medium
prominent dark brown (7.5YR 4/4) mottles; massive;
slightly hard, very friable, slightly sticky and slightly
plastic; slightly acid.
The soils are slightly acid or neutral in the control
section and range from slightly acid to strongly acid
below a depth of 40 inches. Mottles that have chroma
of 3 or more are at a depth of more than 20 inches.
1
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