HomeMy WebLinkAboutEngineer's OWTS Design 07.05.2024129 Cains Lane
Carbondale, CO 81623
970.309.5259
carla.ostberg@gmail.com
July 5, 2024 Project No. C1876
Jenny Vandeventer
Agua.amarga@gmail.com
Subsurface Investigation and Onsite Wastewater Treatment System Design
5-Bedroom Residence
15 Old Orchard Road
Garfield County, Colorado
Jenny,
CBO Inc. performed a subsurface investigation and completed an onsite wastewater treatment system
(OWTS) design for the subject residence. The 3.509 -acre property is located outside of Carbondale , in
an area where OWTSs are necessary. A survey was completed after the original design documents
dated April 15, 2024 were developed. Those should be discarded and replaced with these dated July 5,
2024.
Legal Description: Section: 13 Township: 7 Range: 88 Subdivision: HAWK RIDGE
Parcel ID: 2393-134-01-015
SITE CONDITIONS The property is currently developed with a 3-bedroom residence. A remodel is proposed that will result in
5 total bedrooms.
The residence is served by an existing OWTS. The OWTS consists of a 1000-gallon, two-compartment
Copeland concrete septic tank followed by a pipe and gravel soil treatment area (STA) measuring 18’ x
48’ with 3-feet of gravel below the distribution piping. Garfield County Individual Sewage Disposal
System Permit 1677 documents this system. The system was sized to accommodate 3 bedrooms. The
permit received final approval from Garfield County on May 17, 1989 .
The residence will continue to be served by a community water system. A water line runs from a curb
stop to south along the east side of the yard area. The water line has been identified on the survey
and should also be flagged prior to installation of the STA. The water line must be at least 10-feet from
the proposed septic tank and at least 25-feet from the proposed STA.
An irrigation ditch runs to the west of the proposed STA. The STA must be at least 50-feet from the ditch,
or the ditch may be lined, placed in a culvert, or re-routed where the setback is not met. If relocated, we
assume the ditch must still be within the easement identified in the survey.
The proposed soil treatment area (STA) location has an approximate ten percent slope to the south. The
proposed area is 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 April 4, 2024 by digging two soil profile test pit excavations (Test Pit s). 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 18 -inches, underlain tan sandy
loam to a maximum depth explored of 6.5-feet. Digging beyond 6.5-feet was difficult. No bedrock or
groundwater was encountered.
The materials encountered in Test Pit #2 were similar to those encountered in Test Pit #1. Test Pit #2 was
excavated to a maximum depth explored of 6.5-feet. Digging beyond 6.5-feet was difficult. 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 less than 1-inch in length before breaking. Soil structure
shape was blocky and consistence was friable. Soil texture was more gritty than smooth.
The soil is consistent with Soil Type 2, Sandy Loam, with moderate structure grade. A long-term
acceptance rate (LTAR) of 0.6 gallons per square foot will be used to design the STA.
View of proposed STA Looking from driveway towards house (northeast)
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 Ditch that runs to the west of proposed STA
Photos of the ditch
Page 4
Test Pit #1
Test Pit #1 (looking north) Backfill from Test Pit #1
Looking towards Test Pit #2 from Test Pit #1
Page 5
Sieved sample from Test Pit #1
Test Pit #2 Backfill from Test Pit #2
Page 6
Test Pit #2
DESIGN SPECIFICATIONS
The existing septic tank will be abandoned by pumping the tank and removing it or crushing the top,
bottom, and sides and filling in the void with onsite materials. The existing STA will be abandoned in
place.
Design Calculations:
Average Design Flow = 75 GPD x 2 people/bedroom x 3 Bedrooms + 150 GPD (4th and 5th Bedrooms) =
600 GPD
LTAR = 0.6 GPD/SF
600 GPD / 0.6 GPD/SF = 1000 SF x 1.0 (gravity trenches) x 0.7 (chambers) = 700 SF
The OWTS design is based on 5-bedrooms. An average daily wastewater flow of 600 GPD will be used.
For the purposes of this OWTS design, Benchmark Elevation has been established as 100’ as the
elevation of the existing sewer line entering 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.
OWTS Component Minimum Elevation
Primary Tank Inlet Invert Approximate horizontal distance 78’ from
approximate location tying into the existing sewer
line / min. 2% fall / min. 19.5” fall
Distribution Box Approximate horizontal distance 12’ / min. 1% fall /
min. 1.5” fall
Infiltrative Surface Approximate horizontal distance 44’ to furthest
trench / min. 1% fall to STA / min. 5.5” 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.
Page 7
We recommend utilizing a camera to explore the existing sewer line from the existing septic tank to the
residence. If found to be in good condition, a double-sweep clean out should be installed near the
connection between the existing and new 4-inch SDR -35 sewer line and must have a minimum 2% grade
to the septic tank.
The system installation must include a 1500-gallon, two-compartment Infiltrator® poly septic tank with an
Orenco® Biotube effluent filter on the outlet tee. Risers must bring the manhole lids to grade for access.
If more than one riser is added to the septic tank, an extension handle must be installed on the effluent
filter.
Effluent will gravity flow to a distribution box, and then to six 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 bed.
Each trench will consist of 10 ‘Quick 4’ Standard Plus Infiltrator® chambers for a total of 60 chambers
and 720 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.
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 Infiltrator® IM-1530-2CP 1500-gallon, two-
compartment poly septic
tank
Effluent Filter Orenco® 4-inch diameter, full size
Tank Risers and Lids Orenco® Double-walled PVC Risers and Lids (24” diameter)
Distribution Box Polylok Distribution box, risers, lids, and flow equalizers (5) Chambers Infiltrator® ‘Quick 4’ Plus Standard 60 Chambers
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.
Page 8
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.
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.
Page 9
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.
Sincerely,
CBO Inc.
Carla Ostberg, MPH, REHS
I
I ,GARFIELD COUNTY BUILDING AND SANITATION DEPARTMENT
1.109 8th Street d
Glenwood Springs, Colorado 81do81801
Phone (303) 845 -8212
This does not constitute
INDIVIDUAL SEWAGE DISPOSAL PERMIT .14 1677 a building or use permit.
Owner Chris Locher /Susanne Iioeppli
System Location TM- 1 S kaiak Ridge Snhlivinlnn, t•7trltnylnle
Licensed Installer Owner/Dan Knight
Conditional Construction approval is hereby granted for a 000 gallon
Septic Tank or _Aerated treatment unit.
Absorption area (or dispersal area) computed as follows:
Perc rate of one inch in 2 minutes requires a minimum of 3 l0 0 sq. ft. of absorption area per bedroom.
Therefore the no. of bedrooms 3 x 36 O sq. ft. minimum requirement = a total of ite)R0 sq. ft. of absorption area.
uS r Rio vc 20 a roe /vy> &tee4 4/51-'0 5. 4L a Col-7 ., I,
May we suggest:
2
r r t
Date
FINAL APPROVAL OF SYSTEM:d "
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.
PI< Septic Tank access for inspection and cleaning within 12" of ground surface or aerated access ports above ground
surface.
2K Proper materials and assembly.
r
7 AC Trade name of septic tank or aerated treatment unit. rc, )e/t 1' /000 !y. '/, (nNi c. t ",f(-'. `1' "
f<Adequate absorption (or dispersal) area.. --g " X 4 ? rin id /`y;/ 4 • A
l 1<Adequate compliance with permit requirements.
77 /K Adequate compliance with County and State regulations /requirements.
Date a // 7/8y Inspector I / /.G /; X./
RETAIN WITH RECEIPT RECORDS ATYCONSTRUCTION SITE G
CONDITIONS:
1. All Installation mustcomplywith 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 1, Petty Offense
500.00 tine — 6 months In )ail or both.).
Applicant: Green Copy Department: Pink Copy
INDIVIDUAL SEWAGE DISPOSAL SYSTEM APPLICATION Approval by
County Official:
OWNER 4n.z_,f ZePe J C iarrir r
ADDRESS Aye S3/ 71, er l0 / / //2 PHONE C ?2S er43!6
CONTRACTOR e,n-ey- /,,2a n ryh/
ADDRESS 7)1 id vc.G7 64// /rC i'ccu'cc, J (UC PHONE 6 2c - , no/
PERMIT REQUEST FOR: X) 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 percolation
test holes, soil profiles in test holes. See page 4.)
LOCATION OF PROPOSED FACILITY: County Cja ti -1 t
Near what City of Town e Lot Size J acjcr
Legal Description v . / S ; fi / cx a v % e"S«4; 7, It /4 eV
WASTES TYPE:x) Dwelling Transient Use
Commercial or Institutional Non- domestic Wastes
Other - Describe
BUILDING OR SERVICE TYPE:f / i : ri 4 ran . , rie 1
Number of bedrooms 3 Number of persons 2-4/
Garbage grinder X) 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:o we// Y4n / te,'7
If supplied by community water, give name or supplier:
GROUND CONDITIONS:
Depth to bedrock:v/ /eowvn cc So-2/4i/)
Depth to first Ground Water Table:70/ Asfrown
Percent ground slope:
DISTANCE TO NEAREST COMMUNITY SEWER SYSTEM:7Z
Was an effort made to connect to community system?no
TYPE OF INDIVIDUAL SEWAGE DISPOSAL SYSTEM PROPOSED:
1 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
c) Underground Dispersal Sand Filter
Above Ground Dispersal Wastewater Pond
Other - Describe:
WILL EFFLUENT BE DISCHARGED DIRECTLY INTO WATERS OF THE STATE?n e2
Page 2
SOIL PUCOLATION TEST RESULTS: To be completed by Registered Professional Engineer.)
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.
Nance, address and telephone of RPE who made soil absorption tests:
Name, address and telephone of RPE responsible for design of the system:
Applicant acknowledges that the completeness of the application is conditional upon such
further mandatory and additional tests and reports as may be required by the local health
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 to
such terms and conditions as deemed necessary to insure compliance with rules and regulations
adopted under Article 10, Title 25, C.R.S. 1973, as amended. The undersigned hereby certifies
that all statements made, information and reports submitted herewith and required to be
submitted by the applicant are or will be represented to be true and correct to the best
of my knowledge and belief and are designed to be relied on by the local department of health
in evaluating the same for purposes of issuing the permit applied for herein. I further under-
stand that any falsification or misrepresentation may result in the denial of the application
or revocation of any permit granted based upon said application and in legal action for per-
jury as provided by law.
Date AC%Signed
PLEASE DRAW AND ACCURATE MAP TO YOUR PROPERTY
ptG Ce-n /70K.
Page 3
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ORCHARD ROAD
O
Gar eld County, CO
Developed by
Account
Number
R111539
Parcel
Number
239313401015
Acres 4
Land SqFt 0
Tax Area 011
2019 Mill
Levy
72.5180
Physical
Address
15 OLD ORCHARD RD
CARBONDALE 81623
Owner
Address
VANDEVENTER, JENNIFER
MOORE
15 OLD ORCHARD ROAD
CARBONDALE CO 81623
2019 Total Actual
Value
$1,994,390 Last 2 Sales
Date Price
3/24/2020 $897,500
10/23/1996 $525,000
Date created: 3/6/2024
Last Data Uploaded: 3/6/2024 2:11:33 AM
460 ft
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