HomeMy WebLinkAboutEngineer's OWTS Design129 Cains Lane
Carbondale, CO 81623
970.309.5259
carla.ostberg@gmail.com
October 21, 2023 Project No. C1835
Marc Breslin
mbreslin7@gmail.com
Subsurface Investigation and Onsite Wastewater Treatment System Design
2-Bedroom Residence
34 Kings Row Avenue
Garfield County, Colorado
Marc,
CBO Inc. performed a subsurface investigation and completed an onsite wastewater treatment system
(OWTS) design for the subject residence. The 2.578-acre property is located outside of Carbondale, in
an area where OWTSs are necessary.
Legal Description: Section: 21 Township: 7 Range: 87 FLG # 2 Subdivision: KINGS ROW SUB. 1ST.
Lot: 17
Parcel ID: 2391-213-01-017
SITE CONDITIONS The property is currently developed with a 2-bedroom residence that is served by an existing OWTS.
The OWTS consists of a 1000-gallon, two-compartment concrete septic tank followed by 2 trenches,
each with 9 ‘Standard’ Infiltrator® chambers for a total of 18 ‘Standard’ chambers and 337.5 square feet
of infiltrative area. Garfield County Individual Sewage Disposal System (ISDS) Permit 1917 documents
this system. The system was designed to accommodate 2 bedrooms. The permit received final approval
on October 31, 1991.
The soil treatment area (STA) is experiencing signs of failure and needs to be replaced.
The residence is served potable water from a community water system. While we do not know the exact
location of the water line, a water valve is located on the survey near the northeast corner of the property.
The existing OWTS and replacement are located to the southwest of the residence. No water line should
come within 25-feet of any OWTS component.
The proposed soil treatment area (STA) location has an approximate five percent slope to the west. The
proposed area is vegetated with sage and native grasses.
There should be no traffic or staging of material over the future STA site to avoid compaction of soils
prior to construction of the STA.
Page 2
SUBSURFACE
The subsurface was investigated on October 16, 2023 by digging two soil profile test pit excavations (Test
Pits). A visual and tactile soil analysis was completed by Carla Ostberg at the time of excavation.1
The materials encountered in Test Pit #1 consisted of dark brown topsoil to 6-inches, underlain by light
brown silt clay loam to 2.0-feet, underlain by medium brown silt clay loam to a maximum depth explored
of 6.5-feet. No bedrock or groundwater was encountered.
The materials encountered in Test Pit #2 consisted of light brown silt clay loam to a maximum depth
explored of 8.0-feet. No bedrock or groundwater was encountered.
A sample of the soil was taken from Test Pit #1 at 3-feet below grade. Soil structure grade was
moderate. The soil formed a ball and a ribbon 1 to 2-inches in length before breaking. Soil structure
shape was blocky and consistence was firm. Soil texture was more smooth than gritty.
The soil is consistent with Soil Type 3, Silt Clay Loam, with moderate structure grade. A long-term
acceptance rate (LTAR) of 0.35 gallons per square foot will be used to design the STA.
Test Pit #1 Backfill
Sieved sample Ribbon 1 to 2-inches before breaking
1 Carla Ostberg holds a Certificate of Attendance and Examination from the CPOW Visual and Tactile
Evaluation of Soils Training.
Page 3
Test Pit #1 looking toward Test Pit #2 Test Pit #2
Test Pit #2
DESIGN SPECIFICATIONS
We are providing two options for work on the OWTS. One is replacement of the field only, with sizing for the
existing 2-bedroom residence (2 Bedroom Option). The other will specify replacement of the septic tank as
an option and upsizing the STA to accommodate 3 total bedrooms (3 Bedroom Option).
We recommend running a camera through the existing sewer line from the residence to the septic tank to
verify the sewer line is in good condition. A new, double-sweep clean out should be added on the sewer line
before the septic tank.
For the purposes of this OWTS design, Benchmark Elevation has been established as 100’ as the
elevation of the existing sewer line as it enters the existing septic tank. CBO Inc. should be notified of
any discrepancies or problems with grade elevations of proposed components during installation of the
OWTS.
Page 4
OWTS Component Minimum Elevation
Distribution Box Approximate horizontal distance 12’ / min. 1% fall /
min. 1.5” fall
Infiltrative Surface Approximate horizontal distance to furthest trench
30’ / min. 1% fall to STA / min. 3.75” fall
*Elevations are based upon standard OWTS installation practices. Component elevations may change during
installation due to site conditions. Minimum grade refers to piping between components.
2 BEDROOM OPTION (SEE DETAIL SHEETS W1.0, W2.0, W3.0, W4.0)
The OWTS design is based on 2-bedrooms. An average daily wastewater flow of 300 GPD will be used.
Design Calculations:
Average Design Flow = 75 GPD x 2 people/bedroom x 2 Bedrooms = 300 GPD
LTAR = 0.35 GPD/SF
300 GPD / 0.35 GPD/SF = 857 SF
857 SF x 1.0 (gravity, trenches) x 0.7 (chambers) = 600 SF
The existing 1000-gallon, two-compartment concrete septic tank may remain. A new, 4-inch diameter
Orenco® Biotube effluent filter must be installed on the outlet tee.
Effluent will gravity flow to a distribution box, and then to three gravelless chamber trenches. The
distribution box must be accessible from grade and must have flow equalizers, or similar product,
installed on each outlet pipe in the distribution box to assure equal flow to each trench.
Each trench will consist of 17 ‘Quick 4’ Standard Plus Infiltrator® chambers for a total of 51 chambers
and 612 square feet of infiltrative area. There must be at least 4-feet of undisturbed soil between each
trench. Inspection ports must be installed at the beginning and end of each trench. Ports may be cut to
grade and placed in sprinkler boxes for access.
3 BEDROOM OPTION (SEE DETAIL SHEETS W1.0, W2.1, W3.1, W4.0)
The OWTS design is based on 3-bedrooms. An average daily wastewater flow of 450 GPD will be used.
Design Calculations:
Average Design Flow = 75 GPD x 2 people/bedroom x 3 Bedrooms = 450 GPD
LTAR = 0.35 GPD/SF
450 GPD / 0.35 GPD/SF = 1286 SF
1286 SF x 1.0 (gravity, trenches) x 0.7 (chambers) = 900 SF
The existing 1000-gallon, two-compartment concrete septic tank may or a new, 1000-gallon, two-
compartment poly Infiltrator® septic tank with a 4-inch diameter Orenco® Biotube effluent filter may be
installed.
Effluent will gravity flow to a distribution box, and then to four gravelless chamber trenches. The
distribution box must be accessible from grade and must have flow equalizers, or similar product,
installed on each outlet pipe in the distribution box to assure equal flow to each trench.
Each trench will consist of 19 ‘Quick 4’ Standard Plus Infiltrator® chambers for a total of 76 chambers
and 912 square feet of infiltrative area. There must be at least 4-feet of undisturbed soil between each
trench. Inspection ports must be installed at the beginning and end of each trench. Ports may be cut to
grade and placed in sprinkler boxes for access.
Page 5
COMPONENT SPECIFICATIONS
The component manufacturers are typical of applications used by contractors and engineers in this area.
CBO Inc. must approve alternative components prior to installation of the OWTS. Requests must
be submitted, in writing, to our office for approval prior to installation. Component technical data
sheets are available upon request.
COMPONENT MANUFACTURER MODEL NO. COMMENTS
Septic Tank
(OPTION)
Infiltrator® Item # IM1060-2CP 1000-gallon, 2-
compartment poly septic
tank
Effluent Filter Orenco® 4” diameter full size
effluent filter Distribution Box, risers, lid and flow equalizers
Polylok 3 or 4 ‘Roto-flow’
Chambers Infiltrator® ‘Quick 4’ Plus Standard 51 or 76 cambers
Construction must be according to the jurisdiction’s adopted On-Site Wastewater Treatment System
Regulations, the OWTS Permit, and this design.
PERMIT APPLICATION INSTRUCTIONS
An OWTS Permit Application must be submitted to Garfield County Environmental Health Department.
https://www.garfield-county.com/environmental-health/filesgcco/sites/16/OWTS-Application-Complete-
Packet-Dec.-2019.pdf. If the OWTS Permit Application will be submitted with a Building Permit
Application, it should be submitted directly to Garfield County Building Department.
All questions regarding permit submission can be directed to Garfield County Environmental Health
Department, 970-945-6614 x8150.
INSTALLATION CONTRACTOR
CBO Inc. expects that the installer be experienced and qualified to perform the scope of work outlined in this
design. The installer must review this design thoroughly and coordinate with our office in advance of
installation. Any additional conditions in this design or county permit must be completed and documented
prior to final approval of the OWTS installation. Communication between the installer and this office is
expected throughout the installation.
INSTALLATION OBSERVATIONS CBO Inc. must view the OWTS during construction. The OWTS observation should be performed before
backfill, after placement of OWTS components. Septic tanks, distribution devices, pumps, dosing
siphons, and other plumbing, as applicable, must also be observed. CBO Inc. should be notified 48 hours
in advance to observe the installation.
In an effort to improve the accuracy of the record drawing, we request that the installer provide a
sketch of the installation, including path of the sewer lines, water line installation (if applicable),
septic tank location, STA location, and measurements from building corners or another fixed
objects on the property. This sketch is most easily provided on Sheet W2.0 of the OWTS Design
Packet. Photographs of the installation and final cover are also requested to supplement our installation
documentation.
Page 6
REVEGETATION REQUIREMENTS
An adequate layer of good quality topsoil capable of supporting revegetation shall be placed over the entire
disturbed area of the OWTS installation. A mixture of native grass seed that has good soil stabilizing
characteristics (but without taproots), provides a maximum transpiration rate, and competes well with
successional species. No trees or shrubs, or any vegetation requiring regular irrigation shall be placed over
the STA. Until vegetation is reestablished, erosion and sediment control measures shall be implemented
and maintained on site. The owner of the OWTS shall be responsible for maintaining proper vegetation
cover.
OPERATION INFORMATION AND MAINTENANCE
The property owner shall be responsible for the operation and maintenance of each OWTS servicing the
property. The property owner is responsible for maintaining service contracts for manufactured units,
alternating STAs, and any other components needing maintenance.
Geo-fabrics or plastics should not be used over the STA. No heavy equipment, machinery, or materials
should be placed on the backfilled STA. Machines with tracks (not wheels) should be used during
construction of the STA for better weight distribution. Livestock should not graze on the STA. Plumbing
fixtures should be checked to ensure that no additional water is being discharged to OWTS. For example, a
running toilet or leaky faucet can discharge hundreds of gallons of water a day and harm a STA.
If an effluent filter or screen has been installed in the OWTS, we recommend this filter or screen be cleaned
annually, or as needed. If the OWTS consists of a pressurized pump system, we recommend the laterals be
flushed annually, or as needed.
The homeowner should pump the septic tank every two years, or as needed gauged by measurement of
solids in the tank. Garbage disposal use should be minimized, and non-biodegradable materials should not
be placed into the OWTS. Grease should not be placed in household drains. Loading from a water softener
should not be discharged into the OWTS. No hazardous wastes should be directed into the OWTS.
Mechanical room drains should not discharge into the OWTS. The OWTS is engineered for domestic waste
only.
ADDITIONAL CONSTRUCTION NOTES If design includes a pump, weep holes must be installed to allow pump lines to drain to minimize risk of
freezing. The pump shall have an audible and visual alarm notification in the event of excessively high-
water conditions and shall be connected to a control breaker separate from the high-water alarm breaker
and from any other control system circuits. The pump system shall have a switch so the pump can be
manually operated.
Excavation equipment must not drive in the excavation of the STA due to the potential to compact soil.
Extensions should be placed on all septic tank components to allow access to them from existing grade.
Backfill over the STA must be uniform and granular with no material greater than minus 3-inch.
LIMITS: The design is based on information submitted. If soil conditions encountered are different from conditions
described in report, CBO Inc. should be notified. All OWTS construction must be according to the county
regulations. Requirements not specified in this report must follow applicable county regulations. The
contractor should have documented and demonstrated knowledge of the requirements and regulations of
the county in which they are working. Licensing of Systems Contractors may be required by county
regulation.
Please call with questions.
Page 7
Sincerely,
CBO Inc.
Carla Ostberg, MPH, REHS
3.1 311-fa,Li, • ,L . ,i y wl'r^p r 3h t' 9 " , x ', tr 4L i,,, y""It, l'R,7AV'
O
GARFIELD COUNTY BUILDING AND SANITATION DEPARTMENT
4 109 8th Street Suite 303
Glenwood Springs, Colorado 81601
Phone (303) 945 -8212
This does not constitute
INDIVIDUAL SEWAGE DISPOSAL PERMIT 142 1917 a building or use permit.
Owner Michael L. Ferguson & Terri D. McDonald
System Location 0034 Xinge Row Aventun Carbondale
Licensed Installer o er_
Conditional Construction approval is hereby granted for a 115 gallon
Vd.Septic Tank or Aerated treatment unit,
Absorption area (or dispersal area) computed as follows:
Perc rate of one inch in / 5 minutes requires a minimum of lb. ft. of absorption area per bedroom.
r IF
Therefore the no. of bedrooms __2 x sq. ft. minimum requirement = a total oi''a 2. ft. of absorption area.
May we suggest:
11' i
l
r r---Y 260ftt S' C.)i
Date t r ' .. r/ / 4( -1 '4 InspectoP' { n1.1 y., . ?,,,r
FINAL APPROVAL OF SYSTEM:
No system shall be deemed to be in compliance with the Sewage Disposal Laws until the assembled system is approved prior to cover-
ing any part.
40 00 Septic Tank access for inspection and cleaning within 12" of ground surface or aerated access ports above ground
surface.
Proper materials and assembly.
Trade name of septic tank or aerated treatment unit.
El tt 2 IZotri
t/ r 4_dequat e (or dispersal) area.7
v Adequate compliance with permit requirements.
4 Adequate compliance with County and State regulations /requirements.
J
gOtherDate10- o ^ 9' 1 Inspector
RETAIN WITH RECEIPT RECORDS AT CONSTRUCTION SITE
CONDITIONS:
1. All Installation must comply with all requirements of the Colorado State Board of Health Individual Sewage Disposal Systems
Chapter 25, Article 10 C.R.S. 1973, Revised 1984.
2. This permit is valid only for connection to structures which have fully complied with County zoning and building
requirements. Connection to or use with any dwelling or structures not approved by the Building and Zoning office shall
automatically be a violation of a requirement of the permit and cause for both legal action and revocation of the permit.
3. Any person who constructs, alters, or installs an individual sewage disposal system in a manner which involves a knowing
and material variation from the terms or specifications contained in the application of permit commits a Class I, Petty Offense
500.00 tine — 8 months In )ail or both.).
Applicant: Green Copy Department: Pink Copy
Application
INDIVIDUAL SEWAGE DISPOSAL SYSTEM APPLICATION Approval by
y 1 County Official:
OVER mIG1.1AEL L, Fac r rnpC:C MtI
coADDRESSr>22,4 11e12 lf4,TahorA4 PHONE`() a.15$ k j542.t 9./CONTRACTOR SAvym-gal -s w
ADDRESS PHONE
PERMIT REQUEST FOR: XI New Installation Alteration Repair
Attach separate sheets or report showing entire area with respect to surrounding areas,
topography of area, habitable building, location of potable water wells, soil percolationtestholes, soil profiles in test holes. See page 4.)
LOCATION OF PROPOSED FACILITY: County GAV2.. t€ Lr,
Near what City of Town EL S6 EL Lot Size 2,.74 , q{ikPs
Legal Description 44,r,c - mow 5,,,t T;,;,s,1-0 Z
WASTES TYPE:X) Dwelling Transient Use
Commercial or Institutional Non- domestic Wastes
Other - Describe
BUILDING OR SERVICE TYPE:
Number of bedrooms 2,Number of persons 2
Garbage grinder c) Automatic washer x) Dishwasher
SOURCE AND TYPE OF WATER SUPPLY: X ) well spring stream or creek
Give depth of all wells within 180 feet of system:ink
If supplied by community water, give name or supplier: K,.- to ria .
GROUND CONDITIONS:
Depth to bedrock:la -'t FT
Depth to first Ground Water Table: SFr +/-
Percent ground slope:IO %
DISTANCE TO NEAREST COMMUNITY SEWER SYSTEM:
Was an effort made to connect to community system? OA
TYPE OF INDIVIDUAL SEWAGE DISPOSAL SYSTEM PROPOSED:
x) Septic Tank Aeration Plant Vault
Vault Privy Composting Toilet Recycling, potable use
Pit Privy Incineration Toilet Recycling, other use
Chemical Toilet Other - Describe:
FINAL DISPOSAL BY:
Absorption Trench, Bed or Pit Evapotranspiration
Underground Dispersal Sand Filter
Above Ground Dispersal Wastewater Pond
S) Other - Describe: Inr;,- ra,QTna Swe..-cw,
WILL EFFLUENT BE DISCHARGED DIRECTLY INTO WATERS OF THE STATE? ylp
Page 2
SOIL PERCOLATION TEST RESULTS: To be completed by Registered Professional Engineer.)
r Minutes per inch in hole No. 1 Minutes per inch in hole No. 3
Minutes per inch in hole No. 2 Minutes per inch in hole No._
Name, address and telephone of RPE who made soil absorption tests: ( ,
M M r Lr.
Name, address and telephone of RPE responsible for design of the system:
Applicant acknowledges that the completeness of the application is conditional upon suchfurthermandatoryandadditionaltestsandreportsasmayberequiredbythelocalhealth
department to be made and furnished by the applicant or by the local health department for
purposes of the evaluation of the application; and the issuance of the permit is subject tosuchtermsandconditionsasdeemednecessarytoinsurecompliancewithrulesandregulationsadoptedunderArticle10, Title 25, C.R.S. 1973, as amended. The undersigned hereby certifiesthatallstatementsmade, information and reports submitted herewith and required to besubmittedbytheapplicantareorwillberepresentedtobetrueandcorrecttothebestofmyknowledgeandbeliefandaredesignedtobereliedonbythelocaldepartmentofhealthinevaluatingthesameforpurposesofissuingthepermitappliedforherein. I further under-
stand that any falsification or misrepresentation may result in the denial of the applicationorrevocationofanypermitgrantedbaseduponsaidapplitionandinlegalactionforper-jury as provided by law.
M O'+ •
Date 744(41 Signed {`c. /W
PLEASE DRAW AND ACCURATE MAP TO YOUR PROPERTY
p-r
11;1
Lac y
Y
N
Ro. too
Page 3
i
PLOT PLAN AND DESIGN FEATURES:
Include by measured distance location of wells, springs, potable water supplylines, cisterns, buildings, property lines, subsoil drains, lake, water course,stream, dry gulch and show location of proposed system by direction and distancefromdwellingorotherfixedreferenceobject, and additional submissions in
support of this application such as data, plans, specifications, statements andcommitments.
Eee
Page 4
34 King s Ro w Ave Legend
34 Kings Row St
200 ft
N
➤➤
N
9,028
1,504.7
Map Viewer
This product is for informational purposes and may not have been prepared for, or be suitable for legal,
engineering, or surveying purposes. Users of this information should review or consult the primary data and
information sources to ascertain the usability of the information.
7,0161:
Feet1,1690
Legend
585
Notes
Location
1,169
Date Prepared: 10/18/2023 12:11:10 PM
Well Constructed
Final Permit
County
Gar eld County, CO
Developed by
Account
Number
R011401
Parcel Number 239121301002
Acres 3
Land SqFt 0
Tax Area 011
2019 Mill Levy 81.0290
Physical
Address
34 KINGS ROW AVE
CARBONDALE 81623
Owner Address TORMOHLEN, TAMARA
34 KINGS ROW AVE
CARBONDALE CO
81623
2019 Total Actual
Value
$1,438,570 Last 2 Sales
Date Price
12/16/2019 $795,000
9/21/2001 $625,000
Date created: 9/28/2023
Last Data Uploaded: 9/28/2023 2:07:02 AM
460 ft
Overview
Legend
Parcels
Roads
Parcel/Account
Numbers
Owner Name
Lakes & Rivers
County Boundary
Line