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www.s9m-rnc.com
June t8,2O2l
Mr. Ted White, Environmental Health Specialist lll
Garfield County Public Health
2014 Blake Avenue
Glenwood Springs, CO 81601
RE Porter OWTS
CR244 and Yellow Slide Road
Section 22,T5, R93W
Rifle, CO 81650
Dear Andy,
The purpose of this letter is to provide you soils and design information relative to a tactile soils analysis
that SGM has performed on behalf of the Porter family in support of the installation of an OWTS on the
proposed soil treatment areas located on their property located near CR 244 and Yellow Slide Road in
Rifle, Colorado. The property sits south of Yellow Slide Road in Section 6, Township 65, Range 93W
north and west of the City of Rifle with the lot in the 78.4 acre +f - size. The property parcel number is
2177-062-0A0-4L.
This report and design provides Mr. Porter the direction for which he can construct an OWTS for the lot
considering the development of an OWTS for the 5 bedroom single family house proposed. On the
drawings attached at the end of this report, you will see the necessary OWTS components for the
described situation.
To better acquaint you to the site, we have provided Figure 1 on the following page that is an image
from the Garfield County GIS website. Much of the information discussed above is shown on Figure 1
The specific highlighted lot is that of the Porter property'
GLENWOOD SPRINGS l lB West Sixth St, Suite 200 | Glenwood Springs, CO 81601 | 970.945.1004
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Figurel-SiteLocation
From the NRCS Websoil Survey, the on-site soils (for the STA) are identified as a Potts Loam. The on-site
observations of the Potts loam were characteristic of the clay loam identifíed in the Websoil Survey.
We have attached a soil report from the NRCS Websoil Survey to describe further the expected
characteristics of the soils determined through our pre-site investigation. Ourfindings of the soilconcur
with those characteristics identified by NRCS in their soil investigation for the Websoil information.
Specifically, our findings are as follows:
Depth to ground water is greater than 8 feet.
Depth to limiting layer (ie., ground water or bedrock) is greater than 8 feet.
Other than a limited depth of topsoil, the soil horizon(s) below the topsoil is a consistent clay
loam soil meeting the characteristics of the Soil Type 4 in Table 10-1 of Regulation 43 from
CDPHE.
The soil structure grade was a moderate structure with approximately 50% peds found.
The No. 10 sieve and smaller particles had a blocky/granular soil structure.
The sample contained less than 35% rock.
1.
2.
3.
4.
5.
6.
GTENWOOD SPRINGS I lB West Sixth St, Suite 200 | Glenwood Springs, CO Bl60l | 970.945.10O4
ESGM
www.sgm-rnc.com
The ribbon size from tactile analysis revealed a larger than 2 inch ribbon a smooth texture.
Given these results, the classification for these soils is a Clay Loam, or as previously stated, a
Type 4 Soil per Regulation 43 Table 10-L. (GARCO Table 10-L)
The depth of this soil layer exceeds 8 feet with no groundwater, bedrock nor other limiting layer
encountered.
The proposed OWTS for the single family home will consist of a 1,500 gallon septic tank (for 5 bedroom)
gravity flow from the second compartment of the tank to a distribution box and ultimately the Infiltrator
Quick4 trench systems located north and west of the home.
The soil tactile analysis reveals a Type 4 soil which is reflective of percolation rates of 76-90 mpi.
The loading rate for the Type 4 soil and TL1 is 0.20 gallons/sf/day.
We are recommending constructing the STA in the Potts loam located just north and west of the
building site. This will accommodate a gravity system to infiltrator trenches.
Gravity Trench System
As you will see on the schematic drawings for this alternative and the information attached, the home will
need to utilize either a 1-,500 gallon septic tank (for the 5 bedroom home). The tank is reflected as being
a precast concrete tank (Valley Precast manufactured). A fiberglass or a polypropylene tank (two
compartment) may be used as well as no ground water is anticipated. From the septic tanks, the effluent
would then flow by gravity to the distribution box for the Soil Treatment Area (STA) which is proposed to
be lnfiltrator Quick4 chambers constructed in a trench format. A variety of bends and clean outs would
need to be installed from the tanks to the distribution box. At the distribution box, we are recommending
that Polylok flow distribution weirs be installed to assure equal effluent distribution to each of the
infiltratortrenches. Each of the chambered trenches can be installed at a constant level (ie.,24to48"
below grade) as equal flow distribution is being accomplished through the distribution box and weirs.
There are to be 7 trenches with 25 units each for the 5 bedroom design.
Standard end caps are proposed on the end of each trench along with inspection ports. The piping from
the tank, distribution box and infiltrator trenches shall be a minimum diameter of 4" diameter ASTM 3034
PVC. The location of the tank, distribution box, gravity pipe route and infiltrator trenches will be specified
in the attached drawing plan of this package. Note that the drawing package is prepared in a schematic
format that relies on the contractor/owner to provide adequate grading to accomplish the intent of the
design. ln this manner, it is anticipated that the contractor/owner can provide routing modifications to
make sure that the grading works for the site.
Note that the component construction for the replacement system will need to follow the requírements
of Sections 43.8,43.g and 43.10 of regulation 43 (as adopted by Garfield County) for the tank, distribution
7.
8.
9.
a
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GLENWOOD SPRINGS I lB West Sixth Si, Suite 200 | Glenwood Springs, CO Bl601 | 970.945.1004
ESGM
www.sgm-rnc.com
box, piping and STA as applicable. We have attached a copy of each of these sections for reference by the
contractor/owner to assure each component construction is adequately addressed.
Upon your receipt and review, if you have any questions, please don't hesitate to call
Respectful
S. Simonson, PE, CFM
Principal
ä61 52
6t18t21
GLENWOOD SPRINGS I lB West Sixth St, Suite 200 | Glenwood Springs, CO 81601 | 970.945.1OO4
OWTS Design Report and Calculations
Project Location: SectionClient:Thad Porter
CR244 and Yellow Slide Road
Rifle, CO 81641
Date: 15-Dec-20
Flow Data for the OWTS Design
1 Home Use (5 Bedroom Home)
Home Use
6
6s
93W
Township
Range
600
Total=600
For Home Use, 2 persons per bedroom and 75 gallons per day per person, BODS = 0.06 #/person/day
Totals:
600 gpd
600 gpd
0.48 #/day
o.48 #lday
Soil Data for the OWTS
Data from on-site soil observations:
On site textural analysis reveals clay loam
At a depth of 8', neither bedrock or groundwater have been encountered
Data from the web soil survey indicates a Potts Loam exists. Type 4 soil determined
Average of 3 percolation holes: N/A mp¡ (Soil Tactile Analysis Perfomed)
Given the consideration of all data, the Long Term Acceptance Rate to use is 0.20 gallons/sf/day
Septic Tank Sizing
3 Flow calculated from above: 600 gpd
48 hour detention time for septic tank sizing; Volume= 1200 gpd
lnstall a 1,000 gallon tank for three bedrooms, 1250 for four bedrooms and 1500 gallon tank for 5 bedrooms
Sizing of Absorption Field or Soil Treatment Area
4 Going with a soil type 4 and Treatment Level 1, LTAR =
For a pressure dosed system, size adjustment factor is 1.0 for a bed configuration
For a gravity system, the size adjustment factor shall be 1.2 for a bed configuration
For a gravity trench system, adjustment factor = 1.0
2
0.2 elsf/d
For a pressure dosed trench system, adjustment factor = 0.8
For use of chambersr size adustmentfactor is 0.7
STA= Flow/LTAR 3000 square feet (unfactored)
For a bed system, gravity flow, adjust size to 1.2*3000=
For a chamber system, gravity flow, adjust size to 0.7*3000=
lncorporating a pressure dosed system, adjust size to 0.8*2100=
For a chamber system in a trench configuration, length-
(this would equate to 7 runs of 100 feet each)
3600 square feet
2100 square feet
1680 square feet
700 feet
With the effective length of a Quick4 chamber at 4', use 25 chambers per trench for 7 trenches
(Total length of each trench is 100')
Figure 1- Profíle Hole #1
Soil Testing for
Thad and Morgan Porter OWTS
CR244 and Yellow Slide Road, Rifle, CO
Photo Documentation
Date: 03/09/202L
Figure 2- Profile Hole #21
F tf.
I
Figure j- Sieve Analysis Figure 4- Ribban Test TH -1
Figure 5- Ribbon Test TH -2 Figure 6- THL - Woll Structure
Detailed Soil lnvestigation
This report only covers the tactile evaluation of soil samples collected during profiling appropriately
located on-site test pits. Visual evaluation for the profiling of the test pits is covered under a separate
report.
1.1 Tactile Evaluation
On 6174/2021 SGM conducted the soil textural by feel evaluation on two soil samples collected during
the visual evaluation of two on-site test pits.
The evaluation concluded for each soil sample
1. Sample size = 1,000 ml.
2. Volume of rock > 35 mm (3/4") was 0 ml.
3. Volume of rock < 35 mm (314") > 2 mm (0.079") was 0 ml.
4. Total rock in sample = 0 ml.
5. Percent rock in samPle = 0o/o.
Performing the soil texture by feel methodology on the non-rock portion of the sample TP-l revealed
The soil texture by feel method using the CPOW Soil Texture Flow Chart was conducted on each
sample. Results are shown in the following table.
SAMPLE
Does Soil
Form a Ball
(yes/no)
Does Soil
Form a
Ribbon
(ves/no)
*Type of Ribbon
Formed (Weak,
Moderate,
Stronoì
How Does the Soil Feel
(G ritty/Smooth/N eith er)
TP-1 Yes Yes Stronq Smooth
TP-2 Yes Yes Stronq Smooth
*Weak < L inch; Moderate 1-2 inches; Strong > 2 inches'
The soil felt very smooth when excessively wetted, indicating silty clay
The soil shape for both samples was prismatic and the grade considered to be moderate. Using these
two soil characteristics with the finding of the soil texture by feel methodology indicates this soil
should be classified as soil type 4 with a long term acceptance rate (LTAR) of 0.20 for level 1
treatment (TL-1).
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43.8 Design Criteria - General
Table 7-2 On-eite Wastewater Treatment System Design Gonsideration and Treatment
Requiruments - Separation Distances from $oil Treatment Area
ITEM OWTS DESIGN
DERATION
NOTE: Treatment levels ârê det¡ned in Table 6-3.
Reductions in separation dístanÇ€s with higher level keatment may be gránted only if the local public heallh agency regulaiions
hãve included provisions for operation and rnaintenance.
1 Prior to approval, all setback distance reductions to the 100 foot requirement for wells and soil treatment areas must be in
full compl¡ânce wilh the ff¡nimum standads and variance requirements of the Slate of Colorado Division of Water Resources:
Rulês ând Fegulat¡ons for Water We¡l Construc,tion. Pump llstallation. Cistern
H o lelr/llell Constructio n.
43.8 Desiqn Criteria - General
A. Performance: OWTS shall be designed and constructed to achieve the treatment level specif¡ed
by the design
B, Reliability: OWTS shatt be designed and constructed such that each component sha¡lfunction,
when installed and operated, in a manner not adversely affected by normal operating conditions
including erosion, corrosion, vibration, shock, climatic conditions, and usual household chemicals.
Each component shall be fiee of non-functional protrusions or sharp edges, or other hazards,
which could cause injury to persons, anlmals, or propeÍies. Design shall be such as to exclude
flies and rodents and other vectors and to prevent the creation of nuisances and public health
hazards and shall provide for efficient operation and maintenance.
PRESSURE DOSING REQUIRED
Treatment
Levels I and 2
Treetment
Level 2N
Treatment
Level 3
Treatment
Level 3N
Horizontal Separation
D¡stances
1 Distance from soil
treatment area to on-site
well
Greater than or
equal to 100
feet
Greater than
or equal to
10û feet
Greater than
or equal to
100 feet
Greater than
or equai to 75
feet'
2 Distance from soil
treatment area to pond,
creek, lake, or other
surface water feature
Greater than or
equalt0 50 feet
Greater than
or equal to 25
feet
Greater than
or equal to 25
feet
Greater than
or equal to 25
feet
3 Distance from soil
treatment area to dry
qulclt or eut balrk
Greater than or
equal to 25 feet
Greater than
or equal to 10
feet
Greater than
or equal to '10
feet
Greater than
or equal to 10
feet
Vertical Separation
Distances
4 Deplh in feet from soil
treatment area infiltrative
surface to restrictive
laver or oround water
4 feet (3 feet
with pressure
dosing)
Greater than
or equal to 2
feet
Greater than
or equal to 2
feet
Greater than
or equal to 2
feet
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43.8 Design Criteria - General
Accessibility for lnspection, Maintenance, and Servicing
1- Septic tanks shall have risers over each âccess manhole and all risers shall extend to or
above finalgrade.
2. Each treatment component of an OWTS other than the septic tank and soil treatment
area shall be equipped with access manholes with risers that extend to or above final
grade, located tô permit periodic physical inspection, collection and testing of samples
and maintenance of all components and compartments'
3. Riser Lids
Each riser lid brought to the surface shall have a secure closing mechanism,
such as a lock, special headed bolts or screws, or sufficient weight io prevent
unauthorized access.
b. A tocal public health agency may require a secondary plug, cap, cover or screen
be provided below the riser cover to prevent tank entry if the cover is
unknowinglY damaged or removed.
4. Components that require access for maintenance shall include bui not be limited to
subrnerged bearings, moving parts, pumps, siphons, valves, tubes, intakes, slots,
distribution boxes,lrop boxes, cleanouts, effluent screens, filters, inlet and outlet baffles,
aerators, treatment equipment and other devices.
5. Components shall be designed and constructed so that, when installed, they shall be
easíly maintained, sampled, and serviced according to the manufacturer's
recommendations. Easy physical access to treatment components by maintenance
personnel and equipment shall be provided.
plumbing Codes: Plumbing fixtures, building sewers, vents, sewer lines and other appurtenances
shall be äesigned, operateO and maintained so as to comply with the minimum requirements of
the most recèngy revised locally enforceable plumbing code. ln absence of a local plumbing
code, designs shalladhere to the colorado Plumbing code (3 ccR 720-1).
Electrical EquiPment, lf Used
1. All electrical work, equipment, and material shall comply with the requirements of the
currently applicable National Electrical Code as designated by the State Etectrical Board
Rules and Fiegulations (3 CCR 71A-1)^ A local State electrical permit may be required.
Z. Ëlectrical components shall be protected from moisture and corrosive gases.
lndicators of Failure or Malfunctioning for Systems Utilizing Mechanical Apparatus: A signal
device shall be installed which will provide a recognizable indication or warning to the user that
the system or component is not operating or is operating but malfunctioning. This indication or
*atning shall be a visual signal or an audible signal or both and shall be located in a centralized
area w¡thin visual and audible range of the system user. A signal or message may also be sent
remotely to a maintenance provider.
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43.8 Design Crtterla - General
Sampling Aecess
1. lf sampling for testing or as a requirement for a permit will be required of effluent from a
component other than the soil treatment area, an accessible sampling point shall be
provided.
2. lf sampling of the treated wastewater from the soil treatment area will be required for
testing or as a requirement for a permit, a monitoring well or wells shall be constructed.
Monitoring wells shall be located down gradient from the soil treatment area, accessible,
and provided with a properly securable cover at or above the ground surface. Monitoring
wells up gradient of the system may also be required. Lysimeters or other collection
devices under the soil treatment area may be used instead of a monitoring well if
approved by the local public health agency or other issuer of a permit.
H. ComponentOperatinglnstructions
The manufacturer of proprietary treatment units utilizing mechanical components shall
provide clear, concise written instructions covering the components which, when
followed, shall assure proper installation and safe and satisfactory operation and
maintenance.
2 lf the OWTS uses public domain technology, the design engineer shall provide clear,
concise written instructions covering the componente which, whan followed, shall assure
proper installation and safe and satisfactory operation and maintenance.
Surface Activity: Activity or use on the surface of the ground over any part of the OWTS must be
restricted to that which shall allow the system to function as designed and which shall not
contribute to compaction of the soil or to structural loading detrimental to the structural integrity or
capability of the component to function as designed. During construction, equipment shall be
kept off of the ground surface above the soil treatment area and out of the excavation to prevent
compaction. lf compaction occurs, the disturbed or compacted soil shall be re-evaluated and new
percolation tests may be performed to the disturbed or compacted soil and the system
redesigned if the parameters have changed.
J. Floodplains
New OWTS and replacement OWTS installed in a '1O0-year floodplain shall meet or
exceed the requirements of the Federal Emergency Management Agency and the local
emergency agency. Repairs of an existing system shall meet the requirements as
feasible. The system as approved by a local public health agency shall be designed to
minimize or eliminate infiltration of floodwaters into the system and discharge from the
system into the floodwaters.
2. No new or expanded OWTS shall be installed in a floodway designated in a 1O0-year
floodplain. For any system repair that may affect the floodway delineation, âppropriate
procedures shall be followed including revision of the floodway designation, if necessary
Business Commercial, lndustrial, lnstitutional or Multi-Family Dwelling Wastewater Systems
1. An OWTS that will serve a business, Çommercial, industrial or institutional proper$, or a
multifamily dwelling shall;
a. Be designed by a professional engineer;
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b. Receive only such biodegradable wastes for treatment and dislribution as are
compatible witn tnose biılogical treatment processes as occur within the septic
tank, any additionaltreatment unit and the soittreatment area; and
c. Receive authorization by rule or a class V underground injection permit from the
United States Environm-ental Protection Agency (EPA) before an applicat¡on for
an owTS permit is approved if the system may receive non-residential
wastewatei or is othen¡t¡ise covered úy the EPA underground injection control
program.
43.9 Deçiqn Griterla 'GomPonents
A. Tanks and Vaults
1. Watertightness
a, Septic tanks, vaults, pump tanks, other treatment components, risers and lids
sirål not allow infiltraiion of ground water or surface water and shall not allow the
release of wastewater or liquids through other than designed openings,
b. Acceptable watertightness testing methods performed at a manufacturer's site or
in the field include water filling the tank or vacuum testing.
2. Tank Anchoring: ln locations where ground water or floodwaters mãy cause instability
problems to thã septic tank, vault, or other treatment unit in the OWTS due to flotation,
the tank, vault or unit shall be anchored in a manner sutficient to provide stability when
the tank is empty. Risers shall be included in the buoyancy calculations.
a. lf a manufacturer provides recommendations for anchoring designs, they may be
used if they meet the conditions present at the site.
b. lf a manufacturer does not provide recommendations for provisions to
compensale for buoyancy, or if the professional engineer chooses to provide
his/her own designs, the anctroring system design shall be prepared by the
professional engineer.
3. ldentification and Data Marking: All tanks and treatment units shall be permanently and
legibly marked in a location for the purpose of inspection that is readily visible when
inépeäteO before backfilling. The marking inscription shall include the following:
a. Name of manufacturer;
b. Model or serial number, if available;
c. Effective volume and unìt of measure;
d. Maximum depth of earth cover and external loads the tanks is designed to resist,
and
e. lnlet and outlet identifications, if relevant'
Septic Tanks
1. The manufacturer shall provide sufficient information to demonstrate that the tank w¡ll
meet the design sPecification.
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Sizing Requirements:
a. Sizing for residential capac¡ty for new installations shall be based upon the
number of bedrooms according to Table 9-1:
Table 9-1 llllinimum Tank SÈe Based on Numbor of Bodrooms
Number of Bedrooms Tank Capacity (gallons)
2or3 1,000
4 1,250
Each Additional 250
For multi-family and non-residential applications, a septic tank shall be sized to
permit detention of incoming wastewater design flows for a minimum of 48 hours.
For systems that remove toilet waste for separate treatment, tank capacity may
be less than 1,000 gallons, if it provides a minimum of 48 hours detention time.
Minimum tank size for new installations other than for a single-family residence is
400 gallons.
Testing of Septic Tank Watertightness
a. Testing of septic tanks must be performed and evãluated as specified in section
9 of ASTM Ç1227-12 (Standard Specification for Precast $eptic Ïanks) for
concrete tanks or in Standard IAPMOIANSI 21000-2007 (American Standards for
Prefabricated Septic Tanks) for other prefabricated septic tanks.
Each unit shall be inspected in the field for conditions that may compromise its
watertightness.
The inspection in the field shall be conducted by the local public health agency
and be performed after the tank installation but before backfìlling.
lf the inspection in the field indicates that the tank may be damaged or is not
wateftight, the ¡nspector may require that the tank be tested for watertightness by
the tank manufacturer or the system contractor.
4. Septic Tank Ðesign and Dimension Criteria
A septic tank shall have two or more compartments or more than one tank may
be used in series. The first compartment of a two-compartment tank or the first
tank in a series shall hold no less than one-half of the required effective volume
lnlet invert shall be at least two inches higher than the outlet invert.
tnlet tee or baffle shall extend above the surface of the liquid at least ftve inches
and shall extend a minimum of eight inches below the liquid surface.
Outlet tee or baffle shall extend at least 14 inches below the outlet invert and, if
needed, be modified to accommodate an etfluent screen. The outlet tee or baffle
that accommodates an effluent Screen must be located so that the effluent
t
b.
c.
d
3.
b.
c.
d.
a.
b.
c.
d.
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43.9 Design Criteria - ComPonenis
Ã
screen has sufficient clearance to be removed through the access opening with a
r¡ser in place,
The distance from the outlet invert to the underside of the tank top shall be at
least ten inches.
h.
Liquid depth shall be a minimum of 30 inches and the maximum depth shall not
exceed the tank length.
The transfer of liquid from the first compartment to the second or success¡ve
compartment snall Ue made at a liquid depth of between 35 and 40 percent of the
liquid depth measured from the liquid surface.
At least one access manhole no less than 20 inches across shall be provided in
each compartment of a sePtic tank-
A septic tank shall have a minimum of 25 square feet of liquid s!fface area and
have at least a six-foot separat¡on between inlets and outlets. Septic tanks in
series, combined, shall have a min¡mum of 25 square feet of liquid surface area
and the sum of the distances between inlets and outlets of all tanks must be at
least six feet. The requirements for liquid surface area and separation between
inlet and outlet may be waived for tanks with less than 750 gallon effective
volume.
Concrete Septic Tank Structural Design
a. Concrete septic tanks shall comply with the structural design criter¡a of ASTM
C1227-12 (Standard Specification for Precast Septic Tanks).
b. The design for each tank model and size by each manufacturer must be certified
by a proféssional engineer as complying with these design and structural
réquirements and the waìertightness standard of this regulation.
c.Certification by a professional engineer must be submitted to the Division for
acceptance.
d. Tank slab lids or mid-seam tanks shall be sealed to be watertight-
e. Connections between tank and risers shall be sealed to be watertight.
Fiberglass, Fiberglass-Reinforced Polyester, and Plaslic Tanks
All fiberglass, fiberglass-reinforced polyester, and plastic tanks shall meet the
minimum design and structuralcriteria of IAPMOIANSI 21000-2007 (American
Standards forÞrefabricated Septic Tanks) and be certified by a professional
engineer as meeting these standards. The professional engineer certifying the
critèria must be registered or licensed in the United States, but need not be
registered in Colorado.
All tanks shall be sold and delivered by the manufacturer or manufacturer's
designated representat¡ve, preferably completely assembled. On-site tank
assembly will be allowed on an as-needed basis.
Tanks Shall be structurally sound and support external forces as specified in the
standard referenced above when empty and internal forces when full. Tanks
e.
g,
b.
6.
cr-
c.
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shall not deform or creep resulting in deflectlon of more tha¡r five percent in
ñhape as a rêsult of loads imposed,
All tanks shall be constructed of sound, durable materials and not be subject to
excessive corrosion, decay, frost damage, or cracking.
All seams or connections including to risers shall be sealed to be watertight.
7. Metal tanks are Prohibited.
C. AbandonmentofTank
A tank may be completely removed and the parts disposed of safely
lf the tank will remain in place
The tank shall be pumped to remove as much waste as possible;
The bottom of the lank shall be broken so the tank neither floats nor fills with
water;
The top must be collapsed and the sides may be broken into the void;
The ramaining void shall be filled with gravel, sand or compacted soil; ancl
The filled excavation will be graded to surroundings, allowing for settling.
3.The local public health agency may require abandonment of a tank that is deemed to be
ahazañ.
D. Pipe Standards and Bedding Requirements:
1. Pipe Standards
All wastewater lines used in an OWTS shall be constructed of compatible pipe,
primer, bonding agent, and fittings.
Where unperforated plastic pipe and fittings are used for gravity flow, the
minimum wall thickness of the pipe shall conform to ASTM Standard D 3034 or
equivalent or greater strength. Schedule 40 pipe is preferred.
Perforated distribution pipe surrounded by rock within a soil treatment area shall
have a minimum wall thickness and perforations conforming to ASTM Standard
D 2729 or equivalent or greater strength. Conugated polyethylene pipe with
smooth interior that meets ASTM F405 or AASHTO M252 specifications or
equivalent may be used.
Schedule 40 or pipe of equivalent or greater strength shall be used for the
placement of piping under driveways or roadways and in instances where sewer
line setback distances are granted a variânce for any reason.
Irle prpe, open-joint plpê, ånd ôâst lron plpe must not be used irt a¡r OWTS.
Pressure pipe must be rated for the intended use to accommodate pump
discharge pressure.
d
e.
1
2
a.
b.
c.
d,
e.
a.
b.
c.
d
e.
r
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2. Bedding: All system p¡p¡ng, except for distribution laterals within the soil treatment area,
shall bãbedde-d with select matenal before final inspection by the local public health
agency. Select bedding material shallconsist of loose, g_ranular material, free from
stonei clods, frozen só¡t, or other deleterious material. Select material may consist of on-
site job-excavated or imported material. Bedding material must be mechanically
compacted to suPport PiPing'
E. Distribution Box: A distribution box, if used, shall be of sufficient size to distribute effluent equally
to the lateral lines of a trench or absorption bed system. The box shall be constructed with the
inlet invert at least one inch above the level of the outlet inverts. Flow equalizers or similar
devices shatt be used to adjust the flow between {ines. Access to the box shall be provided with a
manhole riser with access lid at or above grade if the top of the box does not reach final grade.
F. Drop Box; ln sequential or serial distribution, a watertight box may be used to tra.nsfer the
efftuent to the follbwing trench when the effluent in a trench has received the designed level for
overflow to the next trénch. A drop box shall have a riser at or above final grade, if the top of the
drop box does not reach final grade. Outlet lines in sequential distribution shall be designed and
installed so that they may be capped off for resting periods,
G. Step-downlRelief Line: ln sequential or serial distribution, an unperforated pipe may be used to
transfer the effluent to the following trench when the effluent in a treneh has received the
designed level for overflow from that trench.
H. Wastewater Pumping and Dosing Siphon Systems
Pumps
a_
b.
Non-clog pump opening shall have at least two-inch diameter solids handling
capacity where raw wastewater is pumped. A pump opening shall not have more
than 3lá-inch diameter solids handling capacity if previously settled effluent is
pumped.
Pumps must be certified to the applicable UL or CSA electrical safely slandard,
bear the seal of approval of CSA, UL or an equivalent testing program and be
con gtructed of corrosion resistant materials.
Grinder pumps must also be certified to NSF/ANSI Standard 46 and bear the
seal of approval of the NSF or equivalent testing and certification program.
c.
2. Floats and Switches
a
b
Automatic liquid level controfs must be provided to start and shut off pumps at a
frequency or level specified in the design.
Floats must be mounted on a stem separate from the pump discharge piping to
allow for removal, adjustment, and replacement of the float without removing the
pump
Float switches musl be certified to the applicable UL or CSA electrical safety
standard, bear the seal of approval of CSA, UL or an equivalent certification
program and be constructed of corrosion resistant materials.
48
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43.9 Design Criteria - ComPonents
3. Location of Pump or Siphon
A pump may be, or a siphon shall be, installed in a separate tank following the
septic tank and be of sufficient volume to allow pump or siphon cycling
commensurate with the design capacity. The use of a three-compartment septic
tank, sized to provide effective volume in the first two compartments with the
pump in the third compartment, is acceptable.
The second compartment of the septic tank shall not be used as the pump tank
unless it can be demonstrated to the satisfaction of the local public health agency
that the minimum 48-hour detention time will not be decreased and the pump is
screened or provided with an approved filtering device to assure that only liquid
effluent will be discharged.
4. Pump or Siphon Discharge Piping
a.The discharge line from the pumping or siphon chamber shall be protected from
freezing by burying the pipe below frost level or sloping the pipe to allow it to be
self-draining. Drainage shall be provided through the bottom of the pump or
through a weep hole located in the discharge line prior to exiting the tank.
The pump discharge piping shall have a quick disconnect that is accessible
within the riser to allow for easy pump access and removal.
The pipe shall be sized to maintain a velocity of two or more feet per second.
Automatic air/vacuum release valves shall be installed at high points in the
pressure line where necessary to prevent air or vacuum locking and allow self
draining of the lines.
t
The pump or dosing system tank, chamber, or compartment shall have a
minimum 24-inch diameter access riser, made of corrosion-resistant material,
extending to or above ground level.
The access riser must have a watertight connection to the pump or dosing
cham ber/compartrnent lo prevent i nfilttation or exfiltration.
6. Splice Box
Splice boxes shall be located outside the pump system access riser and be
accessible from the ground surface.
No wire splices shall be made inside the tank, dosing chamber or riser. Wire
splicing shall be completed with corrosion-resistant, wâtertight connectors-
7. Controls
The pump system shall have an audible and visualalarm notification in the event
an excessrvely h¡gh water condition occufË.
The pump shall be connected to a control breaker separate from the high water
alarm breaker and from any other control system circuits.
b.
b.
c.
d
Access
a
b.
a
b.
a.
b
49
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c.The pump system shall have a switch so the pump can be manually operated.
The pump system for pressure dosing and higher level treatment systems shall
nave a mechanism for tracking either the amount of time the pump runs or the
number of cycles the pump operates.
Control panels shall be UL listed.
d
Effluent Screens
1. Effluent screens shall be installed in all septic tanks in new installations and repairs
where the sePtic tank is rePlaced.
2. lf e pump or dosing siphon is used to remove septic tank effluent from the final
compartment of thã septic tank, an effluent screen must be provided prior to the pump or
siphän inlet. A pump vault equipped with a filter cartridge may be considered equivalent
to an effluent screen preceding the pump.
3. The effluent screen shall be cleaned at manufacturer-recommended intervals, or more
often, if use Patterns indicate'
4. An alarm may be installed on an effluent screen indicating need for maintenance.
Grease lntercePtor Tanks
1, All commercial food service facilities and other facilities generating fats, oils and greases
in their waste must install a grease interceptor tank"
2. Grease interceptor tanks shall treat only those portions of the total wastewater flow in
which grease and oils are generated'
43.10 Design Criteria- Soil Treatment Area
The size and design of the soil treatment area shall be based on the results of the site and soil
evaluation, desigicrite¡a, and construction standards for the proposed site and OWTS selected
At proposed soil treaiment area locations where any of the following conditions are present, the
system shall be designed by a professional engineer and approved by the local public health
agency:
1. The soil classifications are Types 0, 34, 4, 44, and 5 and Treatment Levels TL2, TL2N,
TL3, and TL3N as specified in Table 10-1 of this regulation,
2. The maximum seasonal level of the ground water surface is less than four feet below the
bottom of the proposed absorption system;
3. A restrictive layer exists less than four feet below the bottom of the proposed absorption
system;
4. The ground slope is in excess of thirty percent; or
A
e.
t.
J
B
5. Pressure distribution is used,
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43.10 Design Criteria- SoilTreatmenl Areå
C. Calculation of lnfiltrative Surface of Soil Treatment Area
The infiltrative surface of a trench or bed receiving any treatment leve¡ of effluent is only
the bottom area. No sidewallcredit is allowed except in deep graveltrenches and
seepage pits that are permissible in repairs.
2- Long-term accept'ance rates (LTARs) are shown in Table 10'1.
3, Factors for adjusting the size of the soil ireatment areâ are in Tables 10-2 and 10-3
4. The required area for a soil treatment area is determined by the following formula:
Soil Treatment Area in square feet required = Desion Flow (in gallons oer dar)
LTAR (in gallons per day per square foot)
Adjusted Soil Treatment Area = Required Soil Treatment Area x Size Adjustment
Facto(s).
Size adjustment factors for methods of application are in Table 10-2-
Size adjustment factors for types of storageidistribution media are in Table 10-3
A rcquired soil treatment area receiving TL1 affluont may be muttiplied by one
size adjustment factor from Table 10-2, Table 10-3, or both.
A soil treatment area receiving TL2, TL2N, TL3, or TL3N effluent must be
pressure dosed. The distribution media in Table 10-3 may be used for
distribution of higher level treatment system effluent, but an additional reduction
factor from Table 10-3 shall not be used.
a-
b.
c.
d.
e.
51
43.10 Design Griteria- Soil Treatment AreaTable 10-1 Soil Treatment AreaAccRatesSoil TextuSoil StructuPercolation Rate and Treatment LevelNoTE: Shaded areas require system dêsign by a professional engineer.1 Treatment levels are defined in Table 6-3.2 Unlined sand filters in these soil lypes shall provide pathogen removal. Design shall conform to section 11 .C.2.c, Unlined Sand Filter$* Higher long-term acceptance rates for Treâtment Level 3N may be allowed for OWTS required to havê â dischârge pemit, if the capability of the design to achieve a higherlong-term acceptence rate can be substantiated.sç¡Io'Ìiì -sNB -qPéL;:"s Eß -ú=l_ró -8 9PÈ-i-ÊßgtsrNr-ODÈã:=Ë3b-t:'¿ ¡ -iöp JE:q=ô: f-oìi rÉP-I r-;TJ_b=?T-Fa+-ö-I-0.300.200.150.800.600_601.401.00TreatmentLevel 3Nr*0.500.300.200.150.800.60r.401.00TreatmentLevel 3!0.150.ã00.400.300.201.250.900.70TreetmêntLevel 2Nr0.150.500.¡f00.300.20f .250.ql0.70TreatrnentLevel 2rM¡nimum z-foot dæp unlinpd send ñtar ËquìËd¡0.200.150.'t00.500350.30ñllinimum3-foot deepunlincdsÊnd filtcrrequired20.800.60Long-term Acceptence Rate (LTAR);Gallons per day per square footLevel 1rTreetm€nt91 -1?0121+4r-6061-757&005-1 5't6-2526-40PercolationRate (MPl)<5IM¡tû¡rrt1,2,32,3tMtülvr2.32 (Moderate)3 (Skong)1 Weak)Mäss¡veUSDA SoilStrucþre-Grade0 (SinglrGrain)0PlrtyGRPR, BK,GR0BK,PR,PR, tsK,GRPR, SK,6R0PR, BK,GR0 (none)PR(Prbmatic)8K(Blocky)GR(Granular)USDA SoilStruoture-ShapeS¡ndy Cl¡y, Ölry, SlltYCtty9dl lypcr 2,44ClrySiltyLorm, CleyChy LÞttñ9rndyLoam,$¡ndychy, Cley, SlþchvSandy Loam, Loam, SiltLoãmSandy Clay Loam, ClayLoam, Silty Clay LoâmSoil Type 1 with morothen 36% Rock (>2mm);Soil Typca 2-5 wilh monüråñ 50% Rock (>zmm)Sand, Loamy SandSandy Loam, Loam, SiltLoamUSDA So¡l Texture1¡lAðI3AI22ASoil Type, Texture, Structure and Percolation Rate RangeSoilTvæ052
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43.10 Design Criteria* SoilTreatment Area
D. Allowable Soil Treatment Area Reductions and lncreases:
The soil treatment area size determined by dividing the design flow rate by the longlerm
acceptance rate may be adjusted by factors for method of treatment, soil treatment area
design, and type of distribution media.
For the purpose of the table, a "baseline system," i.e. adjustment factor of 1.00, is
considered to be Treatment Level 1 {TL1) applied by gravity to a gravel-filled trench.
The maximum reduction from allcombined reductions including higher leveltreatment
shall be no greater than 50 percent of the baseline system required for a soil treatment
area.
Table l0-2
Reductions for use of the higher level treatment categories listed in Table 10-1 shalt only
appty provided the system is inspected and maintained as specified in the requirements
of section 14.D , Perm¡tting and Oversight of Maintenance for Soil Treatment Area
Reductions and Verticaland Horizontalseparation Distance Reductions Based on Use of
Higher Level Treatment.
Size Adjustment Factorc for Methods of Application in Soil Treatment Areas
¿
4.
Treatment Levels I 2 3 and 3N Effluent
Type of Soil
Treatment Area
Method of Effluent Application from Treatment Unit
Preceding Soil Treatment Area
Gravity Dosed (Siphon or
Pump)
Pressure Dosed
Trench 1.0 0.9 0.8
Bed L.2 1.1 1.0
Table l0-3 Size Adjustment Factors for Types of Distribution Media in Soil Treatment Areas
Treetment Level I Effluent
Design of Distribution Systems
L General
a. The infiltrative surface and distribution lines must be level'
Type of SoilTreatment
Area
Type of StoragelDistribution Media Used in SoilTreatment Area
Rock or Tire Chips Manufactured Media
Other Than Chambers
Chambers
Trench or Bed 1.0 0.9 o.7
E-
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b The infiltrative surface must be no deeper than four feet unless adequate
treatment at a deeper level can be demonstrated and is approved by the local
public health agenðy. The depth will be measured on the downslope side of the
trench or bed.
c. Trenches must follow the ground surface contours so variations in infiltrative
surface deplh are minimized. Beds must be oriented along contours to the
degree possible.
d pipe for gravity distribution must be no less than three inches in diameter.
e A final cover of soil suitable for vegetation at least ten inches deep must be
placed from the top of the geotextile or similar pervious material in a rock and
þipe system, chamber, or manufactured media up to the final surface grade of
the soil treatment area.
Following construction, the ground surface must be graded to divert stormwater
runoff or other outside water from the soil treatment area. The area must be
protected against erosion. Subsurface drains upslope of the soil treatment area
may be installed to divert subsurface flow around the area
Backfilling and compaction of soil treatment areas shall be accomplished in a
manner that does not impair the intended function and performance of the
storageldistribution media and soil and distribution laterals, allows for the
establishment of vegetative cover, minimizes settlement and maintains proper
drainage.
2. Distribution Lines
Distribution between lines in a soil treatment area must be as even as possible.
Uneven setfling of portions of the distribution system following construct¡on must
be addressed by provisions in the design to adjust flows between lines.
Distribution lines longer than 100 feet may be pressure dosed or the application
of the effluent shall bê at the center of the line. These systems must be designed
by an engineer.
The end of a distribution pipe must be capped, unless it is in a bed or trenches in
a level soil treatment area, where the ends of the lines may be looped-
lnspection Ports
(1) An inspection port accessible from ground surface must be installed at
the terminal end of each line. The bottom of the inspection port tube
must extend to the infiltrative surface and not be connected to the end of
the distribution pipe. lnspection ports in chambers may be installed
according to manufacturer's instructions if the infiltrative surface is visible
or can be measured from the inspection port.
(2)Additional inspection ports connected to distribution pipes may be
installed.
(3) An inspectron port shall be installed at the ¡nnial end of each line.
f.
g.
a
b
Ç.
d
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(3)
(4)
e Trenches
(1) Trenches must be three feet wide or less.
(2J The separating distance between trenches must be a minimum of six
feet sidewal l-to-sidewal l.
(3)Perforated distribution pipe used in a trench must be as close to the
center of the trench as Poss¡ble,
(4)Perforations must be oriented downward unless pressure distribution is
used and provision for pipe drainage is included.
Beds
(1)Maximum width for a bed must be 12 feet, unless the bed receives
effluent meeting Treatment Level2 quality or better.
(2)The separating distance between beds must be a minimum of six feet
sidewall-to-sidewall.
43.10 Design Criteria- Soil Treatment Area
The top of inspection ports may be below the final grade of the surface if
each has a cover at the surface SUCh as a valve box for a lawn irrigation
system.
The separating distance between parallel distribution lines in an
absorption bed must not exceed six feet and a distribution line must be
located within three feet of each sidewall and endwall of the absorption
bed.
g
Storage/Distribution Media
a. Rock and Pipe
(2)
Serial and Sequential Distributìon:
(1) A serial or sequential distribution system may be used where the ground
slope does not allow for suitable installation of a single level soil
treatment area unless a distribution box or dosing chamber is used
(3)
The horizontal distance from the side of the absorption system to the
surface of the ground on a slope must be adequate to prevent lateral
flow ând surfaclng.
Adjâcent trenches or beds must be connected with a stepdownlrelief line
or ã drop box arrangement such that each trench fills with eff¡uent to the
top of the gravel or chamber outlet before flowing to succeeding
treatment areas.
3.
(1) The pipe must be surrounded by clean, graded gravel, rock, or other
materiat of equal efficiency which may range in size from 1/2 inch to 2
1/2 inches. At least slx inches of gravel, rock or other material rnust be
placed below the pipe, The gravel, rock or other material must fill the
trench around the pipe and at least two inches above the top of the
distribution pipe.
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b.
c.
e.
d.
\2)
Tire Chips
(1) The pipe may be sunounded with clean, uniformly-sized tire chips.
(2) Tire chips must be nominally two inches in size and may range from 112
inch to a maximum of four inches in any one direction'
(3)Wire strands must not protrude from the tire chips more than 0.75
inches.
(4) Tire chips must be free from balls of wire and fine particles less than two
mm across.
(5) The top of the tire chips used must be covered with non-woven
permeable geotextile meeting a maximum thickness rating of 2,0 ounces
per square yard or equivalent pervious material, An impervious covering
must not be used.
Chambers
{1) Chambers must be installed with the base on the inflltrative surface.
(21 lnstallation must be according lo manufacturer's instructions.
(3) Effluent may be distributed by gravity or pressure dosing'
Manufactured Media
(1) Manufactured media must be installed with the base on the infiltrative
surface.
(2) lnstallation must be according to manufacturer's instructions.
(3) Effluent may be applied by pressure distribution only if the manufâcturer
specifles suitability of the product for that use.
Pressure Distriþution
(1) Design of pressure distribution systems must include:
(i) Dose size and frequency for flows and soil or media long-term
acceptance rate;
{i¡} Pipe diameter and strength requirements;
(iii) Orifice size and sPacing; and
(¡v) Distal Pressure head.
(2) Cleanouts must be installed at the end of each line.
The top of the placed gravel or such material used must be covered with
non-wou"n peimeaOlJgeotextile meeting a maximum thickness rating of
2.0 ounces per square yard or equivalent pervious material. An
impervious covering must not be used-
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f. l"tnplines
(1) The infiltrative surface afea must be calculated using the long-term
acceptance rate for the site or a more conservative value if
recommended by the rnanufacturer.
(2) Dripl¡nes must be installed on manufacturer's spacing recommendations.
(3) Drainback must be provided for all drip lines, pipes and pumps.
(4) Provisions must be made to minimize freezing in the distribution lines,
driplines, relief valves, and control systems.
(5) Provisions must be made for backflushing or other cleaning'
F. Alternating and Sequencing Zone Systems
1. Alternating Systems
An alternating system must have two zones that must be alternated on an annual
or more frequent basis.
Each section must be a minimum of 50 percent of the total soil treatment aÍea.
Size adjustment factors for methods of effluent application or type of diskibution
media shall not be allowed.
A diversion valve or other approved diversion mechanism may be installed on the
septic tank effluent line allowing soil treatment area sections to be alternated.
The diversion mechanism must be readily accessible irom the finished grade.
2.Sequencing Zone Systems
a. Sequencing zone systems have more than two soiltreatment area sections that
are dosed on a frequent rotating basis.
Where soil conditions are similar between the sections, each section area shall
be the same size. lf soilconditions are such that long-term acceptance rates are
different, each section may be sized for the same dose, but different long-term
acceptance rates.
c. An automatic distribution vâlve must be used
d. Dosing of each system must be evaluated by the design engineer based on
projected daily flow rates, number of zones, and soil types.
G. Dosing: Dosing may be used for soil treatment area distribution. The dose must be sized to
account for the daily flow and the dosing frequency.
H, Soil replacement must be permitted to bring the soilwithin the requirements of suitable soil.
Added soil must meet the specifications of sand fitter media, as specified in section
43,11,Q.2.al1). All added soil must be completely settled pr¡or to installation of components as
specified and approved by the design engineer. The loading rate for sand filters must be used.
Pressure distribution must be used,
a.
b.
c.
d
b.
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43.10 Design Criteria- Soil Treatment Area
For repairs, potential for risk to public health and water quality may be evaluated
by the locai public health agency. lf risk is low in the determination of the local
püUtic treattli agency, a seepage pit without higher ievel treatment may be used'
lf the risks are not low, higher level treatment of at least TL2 must be attained
prior to discharge to these systems for final disposal.
A seepage pit shall consist of a buried vertical cylinder with holes in the wall.
(r ) Pits must be provided with both vertical sidewall and top supporting
structural concrete or other material of equal structural integrity
(2t The excavation must be larger than the cylinder by at least 12 inches on
each side.
The over-exCavaied volume must be filled with rock ranging in size from
l/2 inch lo 2 112 inches.
Repairs
l-
2
?
When space is not available or if there are other site limitations that preclude other soil
treatmeht area options for OWTS repairs, wide beds, deep gravel trenches, and seepage
pits may be considered for repairs only. Other options are vaults or higher level
treatment systems, if the local board of health permits them'
Wide Beds: For repairs, beds may be wider than 12 feet without being required to
receive effluent meeting Treatment Level 2 quality or better.
Deep Gravel Trenches
a. The length of an absorption trench or bed may be calc_u¡ated by allowance for the
sidewalf area of additional depth of gravel in excess of six inches below the
bottom of the distribution pipe according to the following formula:
Adjusted Length = L x (W+2)
(w+1+2D)
Where
L = length of trench prior to adjustment for deep gravel
W = width of trench or bed in feet
D = additional depth in feet of gravel ¡n excess of the mrnimum required six
inches of gravel below the distribution pipe
Maximum allowable addilional depth is fivei feet.
percolation tests and soil profile hole or soil profile excavation test pit evaluations
must be performed at the proposed infiltrative surface depth.
The reduction in field size ãrea with the use of chambers must not be applied to
deep gravelsystems.
4. Seepage Pits
b.
c,
d
a.
b.
(3)
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(4)
(5)
(6)
Design Criteria - Higher LevelTreatment Systems
The capacity of the pit must be computed on the basls of long-term
atîçeptance rates rletermined for each stratUm penetrated. The weighted
average of the results must be used to obtain a design figure.
soil strata in which the percolation is slower than 30 minutes per inch
must not be used for absorption or seepage. These strata must not be
included in the weighted average to determine the long-term acceptance
rate.
The infiltrative surface of the pit is the vertical wall area (based on dug
perimeter) of the pervious strata below the inlet plus the bottom area
inside the vertical cylinder.
d.
e.The construction of new seepage pits for the treatment and dispersal of on-site
wastewater on ne\¡ìt sites is prohibited unless:
(1) The seepage pit is designed by a professional engineer; and
(2) The design includes higher level treatment of at least TL2'
5. Vaults
a. The allowable use of vaults for repairs in a local jurisdiction is determined by the
local board of health.
b, Criteria for vaults are in section 12.D. of this regulation'
6. Higher LevelTreatment OPtions
a. Reduction in required soil treatment area for repairs is possible with higher level
treätment.
b. Design criteria for higher ¡evel treatment systems are in section 11.
Desian Cr¡têtlâ - Hlohêr Lçvel Treãtment Svstems
General
1. Higher level treatment systems must be designed by a professional engineer.
2. Higher level treatment system$ may be public domain technology systems or proprietary
systems.
a.Public domain technology systems must be designed, installed and maintained
according to establ¡shed criteria and additional criteria established by the local
pubtic neãlth agency. When design criteria are not specifically provided in this
regulation, the criteria used in the design must be from a reference commonly
usêd as an rndustry standard and the Crlter¡a must be cited itr lhe rJesiglt.
Pits must be separated by a dlstance equal to three times the greatest lateral
dimension of the largest pit For pits over 20 feet in depth, the minimum space
between pits must be 20 feet,
43-t1
A.
59
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