HomeMy WebLinkAboutEngineer's OWTS Design PlanGlenwood Springs, CO 81601
phone: (970) 945-7988
fax: (970) 945-8454
email : kaglenwood@kumarusa.com
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Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
ONSITE WASTEWATER TREATMENT SYSTEM DESIGN
PROPOSED ACCESSORY DWELLING T]NIT (ADU) AND GARAGE
PARCEL NO. 186323200099
TBD COUNTY ROAD 150 (SWEETWATER ROAD)
GARFTELD COUNTY, COLORADO
PROJECT NO. 24-7-559.02
JANUARY 22,2025
PREPARED FOR:
TED VICKERMAN
P. O. B,OX342
AVON' COLORADO 81620
tedvic@comcast.net
TABLE OF CONTENTS
INTRODUCTION ....
PROPOSED CONSTRUCTION
SITE CONDITIONS.......
SUBSURFACE CONDITIONS
OWTS ANALYSIS .
DESIGN RECOMMENDATIONS ........
SOIL TREATMENT AREA...
OWTS COMPONENTS
OWTS OPERATION AND MAINTENANCE.............
OWTS HOUSEHOLD OPERATION
OWTS MAINTENANCE......
OWTS CONSTRUCTION OBSERVATION
LIMITATIONS.
FIGURES
FIGURE 1 _ OWTS SITE PLAN
FIGURE 2 _ USDA GRADATION TEST RESULTS
FIGURE 3 _ SOIL TREATMENT AREA CALCULATIONS
FIGURE 4 - SOL TREATMENT AREA PLAN VIEW
FIGURE 5 _ SOIL TREATMENT AREA CROSS SECTION
ATTACHMENTS
VALLEY PRECAST 1,OOO GALLON, TWO-CHAMBER SEPTIC TANK DETAIL
1
I
1
-2-
-J-
I
1
5
6
6
J-
-6-
-6-
POLYLOK DISTRIBUTION BOX
INTRODUCTION
This report provides the results of an onsite wastewater treatment system (OWTS) design for
a proposed accessory dwelling unit (ADU) to be located atParcelNo. 186323200099, TBD
County Road 150 (Sweetwater Road), Garfield County, Colorado. The project site location is
shown on Figure 1. The purpose of the report is to provide design details for the OWTS in
accordance with the Garfield County Environmental Health Department Onsite Wastewater
Treatment System Regulations and the Colorado Department of Public Health and
Environmental Regulation#43. The services were performed supplementary to our agreement
for professional services with Ted Vickerman dated September 19,2024.
PROPOSED CONSTRUCTION
The proposed ADU and garage will be a two-story, wood-frame structure located on the site as
shown on Figure 1. The structure will consist of the ADU over a ground floor garage. The ADU
will have two bedrooms. The OWTS will be designed for two bedrooms. The proposed soil
treatment area (STA) for the OWTS will be located to the southeast of the ADU as shown on
Figure 1. Water service will provided by a well located northwest of the ADU. The route of the
water supply line to the ADU has not yet been determined.
If proposed construction is different than that described, we should be contacted to re-evaluate
our design recommendations.
SITE CONDITIONS
The site was a vacant pasture and hay field at the time of our field exploration. The tenain is
gently to moderately sloping down to the south at about 5 to 10 percent grade. There are visible
basalt boulders and cobbles on the ground surface. Vegetation consists of grass, brush and
scattered stands of cottonwood trees.
SUBSURFACE CONDITIONS
The field exploration for the OWTS was conducted on October 14,2024. Two profile pits
(Profile Pits 1 and2) were excavated with an excavator at the approximate locations shown on
Figure 1 to evaluate the subsurface conditions at the planned soil treatment area for the OWTS
The pits were logged by a representative of Kumar & Associates. Logs of the profrle pits are
provided below.
Log of Profile Pit 1
Depth USDA Classilication
O-lY2'TOPSOL; organic Sandy Loam, gravelly, firm, slightly moist, brown.
lVz'-9'SANDY LOAM; gravelly, moderate blocky structure, dense, slightly moist, brown.
a
a
Bottom of pit @ 9feet.
No sroundwater or redoximornhic features observed at time of pit excavation.
Depth USDA Classification
0- 1'TOPSOL; organic Sandy Loam, gravelly, firm, slightly moist, brown.
l'-8'SANDY LOAM; gravelly, moderate blocky structure, dense, slightly moist, brown.
a
a
a
Disturbed bulk sample obtainedfrom 4 to 6feet.
Bottom of pit @ 8feet.
No sroundwqter or redoximorphic features observed at time of pit excwation.
Log of Profile Pit 2
The soils encountered in the profile pits, below about I to l% foot of organic topsoil, consisted
of gravelly Sandy Loam down to the pit depths of 8 to 9 feet. Hydrometer and gradation
analyses were performed on a disturbed bulk sample of the soils from Profile Pit 2 from 4 to
6 feet depth with the results provided on Figure 2. The tested sample (minus No.l0 size sieve
fraction) classifies as Sandy Loam per the USDA system. No free water was encountered in the
pits nor indications of seasonal high groundwater were observed at the time of the pit
excavations.
Based on the subsurface conditions and laboratory testing, the soils at the STA have been
classified as Type 2 per State regulations, which equates to a long-term acceptance rate (LTAR)
of 0.60 gallons per square foot per day.
OWTS ANALYSIS
Based on the site conditions and profile pit evaluations, the evaluated area should be suitable for
a conventional infiltration disposal system. There is adequate elevation difference from the
ADU down to the STA for gravity flow of the sewer effluent. The STA will consist of chambers
in a trench configuration based in the Sandy Loam soils. The STA will be sized for two
bedrooms (4 persons) with an average daily flow of 75 gallons per person, and an LTAR
of 0.60 gallons per square foot per day for the natural soils.
The effluent will gravity flow from the ADU to the septic tank for primary treatment and then
gravity flow to the STA for dispersal and final treatment. The STA will consist of two trenches
with Infiltrator Quick 4 Plus Standard chambers. Equal distribution will be provided to the
chambers and trenches by a distribution box.
The well is far outside of any setbacks to the OWTS. The route of the planned water supply line
to the ADU is currently not designed. The required setback to the water line from the septic tank
is 10 feet, 5 feet for sewer and effluent lines, and 25 feet from the STA. We should be notified
for additional recommendations if the water line is within these minimum setbacks.
DESIGN RECOMMENDATIONS
The design recommendations presented below are based on the proposed construction, the site
and subsurface conditions encountered and our experience in the area. A layout ofthe proposed
OWTS components is provided on Figure 1. If conditions encountered during construction are
different than those that are described in this report, we should be contacted to re-evaluate our
design recofllmendations.
SOIL TREATMENT AREA
o The STA will consist of two trenches with 15 Infiltrator Quick 4 Plus Standard chambers
placed in each trench (30 chambers total) in the native soils. Equal distribution will be
provided to the trenches by a distribution box.
o The STA was sized based on an LTAR of 0.60 gallons per square feet per day.
. Each chamber was allowed 12 square feet of area. A30% reduction of the STA size was
applied for use of Infiltrator chambers in a trench configuration. The total STA design
size is 360 square feet. Soil treatment area calculations are shown on Figure 3.
o A minimum of four feet of undisturbed soil between trenches is required.
o Trench cut depths should be a maximum of 4 feet deep.
o The trenches should be oriented along ground contours to minimize soil cut and cover.
o The base and sidewalls of the trench excavations should be scarified prior to the chamber
placement.
o A minimum of 12 inches and a maximum of 24 inches of cover soil should be placed
over the chambers.
. Backfill should be graded to deflect surface water away from the STA and should be
sloped at3 horizontal to 1 vertical or flatter. A swale to divert surface water flow away
from the STA may be needed.
o Disturbed soil should be re-vegetated as soon as possible with a native grass mix. No
trees, shrubs or other plants with deep roots should be planted on or near the STA as this
may damage the system piping.
o Four-inch diameter inspection ports should be installed vertically into the knockouts
provided in the chamber end caps. Install ports at each end of the trench. The inspection
port piping should be screwed into the top to the chambers and should not extend down
to the ground surface inside the chambers. The inspection ports should extend at least
8 inches above the finished ground surface or be protected in a valve box at finished
grade.
o The STA must be a minimum of 5 feet from the septic tank.
o The STA must be a minimum of 25 feet from any potable water supply lines.
o The STA must be a minimum of 20 feet from the ADU.
o A plan view of the STA is presented on Figure 4 and a cross section of the STA is
presented on Figure 5.
OWTS COMPONENTS
Recommended OWTS components provided below are based on our design details and our
experience with the specific component manufacturers. Equivalent components may be feasible
but need to be approved by us prior to construction.
Septic Tank
o A Valley Precast 1,000 gallon, two-chamber septic tank should be used. A detail of
the tank is provided as an attachment.
o An effluent filter should be installed in the tank outlet tee.
o The tank must be a minimum of 5 feet from the ADU and the STA.
o The tank must be a minimum of 10 feet from any potable water supply lines or irrigation
lines.
o The tank must be set level. The excavation bottom must be free of large rocks or other
objects that could damage the tank during placement. A road base or gravel bedding
material may be needed to prevent tank damage during placement and act as a leveling
course.
o The tank lids must extend to final surface grade and made to be easily located.
o Install the tank with2 feet minimum cover soil for frost protection. Maximum tank
soil cover is 4 feet.
Sewer Pipe
o The sewer line to the septic tank should not be less than the diameter of the building
drains and not less than 4 inches in diameter.
o The sewer pipe should have a rating of SDR35 or stronger.
o Schedule 40 PVC pipe is required beneath any driveway surfaces.
o The sewer pipe should be sloped between 2o/olo 4o/oto help limit disturbance of solids
in the tank and potential sewage bypass of the first chamber of the tank. If a steeper
slope is needed, this can be accomplished with vertical step-downs in the sewer line.
o A minimum 18 inches of cover soil should be provided over the sewer pipe. Paved areas,
patios or other areas without vegetative cover may be more susceptible to frost and we
recommend 48 inches of soil cover over the sewer pipe in these areas, and the pipe be
insulated on top and sides with 2-inch-thick blue foam insulation board. If adequate soil
cover is not possible, we should be contacted for re-evaluation prior to installation.
o The sewer pipe should be bedded in compactedt/o-inchroad base or native soils provided
that the native soils contain no angular rocks or rocks larger than2% inches in diameter
to help prevent settlement of the pipe. Sags in the pipe could cause standing effluent to
freeze and damage the piping.
o Install cleanout pipes within 5 feet of the building foundation, where the sewer pipe
bends 90 degrees or more and every 100 feet of sewer pipe.
. All 9O-degree bends should be installed using a 9O-degree long-sweep or by using two
45-degree elbows.
o The sewer line location shown on Figure I is considered conceptual. We assume that
there will be only one sewer line exiting the ADU. It is the responsibility of the owner/
contractors to locate all sewer line exit locations and connections to the septic tank.
We should be notified if there are other sewer lines exiting the building.
Effluent Transport Piping
o The effluent transport pipe should be 4-inch diameter SDR35 piping sloped at a2o/o
minimum to flow from the septic tank to the distribution box and from the distribution
box to each trench. Piping should extend at least 6 inches into the top knockout provided
in the Infiltrator end caps and be screwed in place. Splash plates should be installed
beneath the inlet piping to help limit scouring of the infiltrative soil surface in the
chambers.
o The effluent transport pipe should be bedded in compactedtk-inch road base or native
soils provided that the native soils contain no angular rocks or rocks larger than
2Yrinches in diameter to help prevent settlement of the pipe. Sags could cause standing
effluent to freeze and damage to the piping.
o A minimum 18 inches of cover soil should be provided over the effluent transport pipe.
Paved areas, patios or other areas without vegetative cover may be more susceptible to
frost. We recommend 48 inches of soil cover over the effluent pipe and insulation with
at least 2 inches of rigid foam insulation in these areas. If adequate cover soil is not
possible, we should re-evaluate the condition prior to installation.
o Schedule 40 PVC pipe is required underneath driveway surfaces and should be provided
with at least 48 inches of soil cover and be insulated on top and sides with 2-inch-thick
rigid foam insulation board.
o All 9O-degree bends should be installed using a 90 degree long-sweep or by using two
45-degree elbows.
Distribution Box
o The distribution box will be used to equally divide effluent flow between the trenches.
We recommend a Polylok Distribution Box since it is easily accessible from ground
surface for maintenance. A copy of the distribution box detail is provided as an
attachment to this report.
o. The distribution box outlet pipes should be equipped with levelers for eose of initial setup
and adjustment over time.
o The distribution box should be a minimum of l8 inches below grade with risers andarr
access lid at or above grade.
o The distribution box must be accessible from ground surface for inspection and
maintenance per the State guidelines.
o The effluent line from the septic tank should be directed downward into the distribution
box with a 90-degree elbow inside the box.
r The distribution box must be installed level on a compacted road base subgrade to ensure
equal effluent distribution. If settlement of the distribution box occurs, unequal effluent
distribution may take place which could cause hydraulic overload of one of the trenches
and potential failure. The distribution box should be monitored periodically, and the
levelers should be adjusted as necessary for levelling.
o The ground surface above and around the distribution box should be graded to drain away
surface water to prevent standing water near the distribution box which could freezs or
cause settlement.
OWTS OPERATION AND MAINTENANCE
The OWTS will require periodic inspection and maintenance to function properly. A properly
designed, installed and maintained system can greatly increase its lifespan. The level of
maintenance will vary depending on the complexity of the system and water use habits of the
residents. We recommend that an OWTS Operation and Maintenance (O&M) Manual be
developed. Depending on the complexity of the system, a contract with an OWTS maintenance
provider may be prudent. Below are some basic recommendations for the OWTS O&M.
OWTS HOUSEHOLD OPERATION
o Use of high efficiency water fixtures is recommended to decrease the hydraulic load
on the OWTS system.
o Fix plumbing leaks immediately as this may cause a hydraulic overload of the soil
absorption system.
o Do not irrigate the area on top of or directly upgradient of the STA field as this may
cause a hydraulic overload.
o Do not dispose of household waste down drains as this may clog or damage OWTS
components. Examples of household waste include: dental floss, cotton swabs, coffee
grounds, paper towels, feminine products and many other kitchen and bath items.
o Use of kitchen garbage disposals is not recommended. If a garbage disposal is utilized,
kitchen wastewater should be screened thoroughly. Many kitchen solids are not
decomposed in the septic tank and may cause increased tank pumping frequency.
o Do not dispose of household chemicals, greases, oils, paints, hot tub water or water
softener backwash in household drains. A separate drywell, if feasible, may be necessary
for hot tub water or water softener backwash disposal.
o Limit the use of bleach as this may harm useful bacteria in the septic tank and soil
absorption system.
o Liquid dishwasher and clothes washer detergent is recommended for households served
by an OWTS. Clay substances used as fillers in powder detergents may result in
clogging of the soils absorption system.
OWTS MAINTENANCE
o Inspect the septic tank, distribution box and STA at least annually for problems or signs
of failure.
o The effluent filter for the tank should be cleaned at least annually by spray washing solids
into the first chamber of the septic tank.
o The septic tank should be pumped and cleaned every 3 to 5 years depending on use.
Longer pumping intervals may increase the amount of solids that reach the STA, which
may shorten its life span.
. Pumping of the septic tank should take place when the level of the sludge and scum
layers combined take up 25 to 33Vo of the capacity of the first chamber of the tank.
OWTS CONSTRUCTION OBSERVATION
The Garfield County Environmental Health Department requires that the designer of the system
provide a record drawing and certification of the OWTS construction (As-Built inspection).
We should be provided with at least 48-hour notice prior to the installer needing the inspections.
Prior to issuance of our certification letter, we require observation of all system components
prior to backfill. The number of site visits required for the inspection will depend on the
installer's construction schedule.
LIMITATIONS
We have conducted this design in accordance with generally accepted engineering principles and
practices in this area at this time. We make no warranty either expressed or implied. The
recoflrmendations provided in this report are based on the site conditions, profile pit evaluations
and soil texture analysis, the proposed construction and our experience in the area. Variations in
the subsurface conditions may not become evident until excavation is performed. If conditions
encountered during construction appear different from those described in this report, we should
be notified so that re-evaluation of the recommendations may be made.
This report has been prepared for the exclusive use by our client for design pu4)oses. We are not
responsible for technical interpretations by others of our information. As the project evolves, we
should provide continued consultation and field services during construction to review and
monitor the implementation of our recommendations, and to verifr that the recommendations
have been appropriately interpreted. Significant design changes may require additional analysis
or modifications to our design.
It is our opinion that the designed location of the OWTS components does not violate any
setback requirements of the current Garfield County Regulations. Below is a table of common
minimum horizontal setbacks to OWTS components. Refer to the Garfield County Regulations
for a complete list ofrequired setbacks. We recommend the OWTS components be surveyed by
a Professional Colorado Land Surveyor.
Table I - Common Minimum Horizontal Setbacks from OWTS Components
WeIls
Water
Supply
Line
Occupied
Dwelling
Lined
Ditch
Lake,
Irrigation
Ditch,
Stream
Dry
Ditch or
Gulch
Septic
Tank
STA 100'25',24',10'50'25 5
Septic Tank 50'10'5'l0'50'10'
Building Sewer 50'5',0'l0'50'l0'
Please contact us for any necessary revisions or discussion after review of this report by Garfield
County. If you have any questions, or if we may be of further assistance, please let us know.
Respectfully Submitted,
Kumar & Associates, Inc.
#d'
.#,'rfe{ I;*"
Shane M. Mello, Staff Engineer
Reviewed
David A. Young,
SMMlkac
z7Z
PARCEL No.
1 86525200099
TBD COUNTY ROAD 150
(SWEETWATER RoAD)
PROPOSED
WELL
PROPOSED SOIL TREATMENT
AREA (STA) CONSTSTTNG OF2 ROWS OF 15 INFILTRATOR
QUICK4 PLUS STANDARD
CHAMBERS ORIENTED ALONG
GROUND CONTOURS.
(30 CHAMBERS
CLEANOUT
PROPOSED VALLEY
PRECAST
1,000-GALLON,
TWO-CHAMBER
SEPTIC TANK
PROPOSED
POLYLOK
DISTRIBUTION
BOX
I PROFILE
PIT 2
PROPOSED
ADU AND
GARAGE
PROFILE
PIT 1
oto
25
tNc.
a{oe
p
50o
tu4
SCALE-FEET
200 0
coUNTY RoAD 150 (SWEETWATER ROAD)
SCALE-FEET
24-7*559.02 Kumar & Associates OWTS SITE PLAN Fig. 1
=
E
a
E
d2
too
90
EO
70
60
30
,l{,
50
20
t0
o
o
lo
20
30
&
30
60
70
ao
90
too
,o57
DIAMETER OF PARTICLES IN MILLIMETERS
CLAY
mm .02 .05 .l
SAMPLE OF: GRAVELLY SANDY LOAM
FRoM: PROFILE PIT 2 AT 4 TO 6 FEET
NOTE: Hydromeler Anolysls vos performed on o
bulk somple followlng screenlng o{ oll moleriol
lorger lhon the flO sieve (2.0 mm) per USDA
guid6lin€s.
mm
ENTIRE SAMPLE
PARTICLE SIZE DISTRIBUTION X
COBSLES 0
GRAVEL 35
SAND 58
SILT 22
CLAY 5
PORTION OF SAMPLE
PASSTNG #10 STEVE
PARTICLE SIZE DISIRIBUTION X
SAND 5E
SILT 31
CLAY I
TOTAL SAMPLE RETAINED ON f,10 SIEVE: 35X
PERCENT OF MATERIAL RETAINED ON #10 SIEVE
PASSING 3/1" SIEYE: 51X
ThG. lcll rrlull! opply only lo th.
sqmplc! whlch wsE losl6d. Tho
lodlng ruport lholl not b! nproduc€d,
sxcspf ln full, wfhoul lho wrltlonqpprcyol ol Kumor & Asloclqh!, lnc.
Sloe cnolyrls lsdlng l! pirfomod ln
occordonc€ ullh ASTU D,[22, ASIM Cl36qnd/or ASTII 01140.
COBBLES
.25 .5
SIEVE ANALYSISHYDROMETER ANALYSIS
CLEAR SOUARE OPENII{OSTITE RroING
2' HRS 7 HRS t6n tlo
U.S. STAI{DARD SERIES
ls ata
SAND GBAVELSILT
MEDIUM m vco FINE MEDIUM COARSEFINFco.V. FINE FINE
GRAIN SIZE
(mm)SIEVE SIZE X FINER
127.OO 5"100
76.00 100
38.1 0 1-1 /2'90
19.05 3/1"a4
9.50 3/8"77
1.75 *1 71
2.00 tl0 65
1.00 #18 59
o.50
'135
55
0.25 *60 /t5
0.1 06 *1/t0 55
o.053 1270 27
GRAIN SIZE
(mm)
TIME PASSED
(min)X FINER
o-o37 1 25
0.019 I 21
0-009 19 11
0.005 60 10
0.002 /+55 5
0.001 I 545 3
24-7-559.O2 Kumar & Associates USDA GRADATION TEST RESULTS Fis. 2
OWTS SOIL TREATMENT AREA CALCUTATIONS
In accordance wtLh the Garfieb County OWTS Regulatbns and the Cobrado Depaftment of Pubk Health
and Envlronment's Regulatbn #43, the soil treatment area uas cahulated as fobun:
CALCULATTON OF OvtfiS DESTGN FLOW:
q = (F)(N)
N = 2 PERSONS PER BEDROOM
WHERE:
Q = DESIGN FLOW
F = AVEMGE FLOW PER PERSON PER DAY
B = NUMBER OF BEDROOMS
N = NUMBER OF PERSONS
75 GALLONS PER DAY
2 BEDROOMS
4 PERSONS
3OO GAIIONS PER DAY
SOIL TREATMENT AREA:
F
B
N
a
CALCULATION OF OWTS
MINIMUM SOIL TREATMENT AREA =s00.0 SQUARE FEET
REDUCTION FACTOR FOR CHAMBERS =0.70
MINIMUM SOIL TREATMENT AREA WITH REDUCTION = 35O SQUARE FEET
MINIUMUM TREATMENT AREA = Q + LTAR
WHERE:
Q=
LTAR (SOIL TYPE 2) =
AREA PER INFILTMTOR QUICK 4 STANDARD CHAMBER =
TOTAL CHAMBERS NEEDED =
NUMBER OF TRENCHES =
CHAMBERS PERTRENCH =
TOTAL NUMBER OF CHAMBERS AS DESIGNED =
TOTAL SOIL TREATMENT AREA =
3OO GALLONS PER DAY
0.6 GATLONS/FTTDAY
12 SQUARE FEET
30 CHAMBERS
2 TRENCHES
15 CHAMBERS
30 CHAMBERS
35O SQUAREFEET
24-7-559.02 Kumar & Associates SOIL TREATMENT AREA CALCULATIONS Fig. 3
4 INCH DIAMETER
NON-PERFORATED
SDR55 TRANSPORT
PIPE SLOPED AT A
2% MIN. DOWN TO
DISTRIBUTION BOX.
4 INCH DIAMETER PVC
OBSERVATION PORTS
INSTALLED VERTICALLY INTO
THE KNOCKOUTS PROVIDED IN
END CAPS. INSTALL PORTS
AT EACH END OF EACH
TRENCH. REMOVABLE LID TO
BE PLACED ON TOP OF PIPE.
PIPE MUST STICK UP AT
LEAST 8 INCHES ABOVE
FINISHED GRADE OR BE
PLACED AT GRADE IN AN
ACCESSIBLE VALVE BOX.
PIPES SHOULD NOT EXTEND
TO SOIL SURFACE AND
SHOULD BE SECURED TO
CHAMBER WITH SCREWS OR
COUPLINGS TO PREVENT
SLIDING DOWNWARD.
POLYLOK
DISTRIBUTI
BOX
4 INCH DIAMETER
NON-PERFORATED
SDR55 TRANSPORT
PIPE SLOPED AT A
2% MIN. DOWN TO
TRENCH.
INFILTRATOR
QUICK 4 PLUS
STANDARD END
CAP.
TRANSPORT PIPING SHOULD BE
INSERTED AT LEAST 6 INCHES
INTO THE UPPER KNOCKOUT IN
THE END CAP. INSTALL SPLASH
PLATES BENEATH INLET PIPING
TO HELP LIMIT SCOURING OF
THE INFILTRATIVE SURFACE.
INFILTRATOR QUICK4 PLUS
STANDARD CHAMBERS ]N 2
TRENCHES. 15 CHAMBERS
PER TRENCH (30 TOTAL).
20
SCALE_FEET
Noies1. Chambers should be installed level on a scarified ground surface. Concrete sand may be used as a leveling course if
necessary.
2. Care should be taken by the contractor to avoid compaction of the native soils in the trench areas. The base and side walls of
trench excavations should be scarified prior to chamber installation.
3. All piping should have a rating of SDR35 or stronger.
4. Changes to this design should not be made without consultation and approval by Kumar & Associates.
5. Refer to the Garfield County Onsite Wastewater System Regulations for other applicable specifications.
Fis. 4
l'$\$'
24-7-559.42 Kumar & Associates SOIL TREATMENT AREA PLAN VIEW
NATIVE SOILDISTURBE
N
SOIL
BETWEEN
SCARIFY GROUND
SURFACE PRIOR TO
CHAMBER PLACEMENT
EXCAVATE 56''
WIDE TRENCH
12" MlN./24" MAX.
COVER SOIL GRADED
TO DEFLECT
SURFACE WATER
Notes
GRO UND
Chambers should be installed level on a scarified ground surface. Concrete
sand may be used as a leveling course if necessary.
Care should be taken by the contractor to avoid compaction of the native soils in
the trench areas. The base and side walls of trench excavations should be
scarified prior to chamber installation.
Changes to this design should not be made without consultation and approval
by Kumar & Associates.
INFILTRATOR QUICK 4
PLUS STANDARD
CHAMBER INSTALLED
LEVEL
2.5 0
SCALE-FEET
2
24-7-559.02 Kumar & Associates SOIL TREATMENT AREA CROSS_SECTION Fis. 5