HomeMy WebLinkAboutEngineer's OWTS Design Plan129 Cains Lane
Carbondale, CO 81623
970.309.5259
carla.ostberg@gmail.com
May 7, 2024 Project No. C1872
Brian Long
marmotflavored@gmail.com
Subsurface Investigation and Onsite Wastewater Treatment System Design
6-Bedroom Residence
40 Pine Street
Garfield County, Colorado
Brian,
CBO Inc. performed a subsurface investigation and completed an onsite wastewater treatment system
(OWTS) design for the subject residence. The 15,750-square foot property is located outside of
Carbondale, in an area where OWTSs and wells are necessary.
Legal Description: Section: 28 Township: 7 Range: 88 Subdivision: COOPERTON TWNSTE. Block: 12
Lot: 21 THRU:- Lot: 24 15750 SQUARE FEET
Parcel ID: 2393-284-12-005
SITE CONDITIONS The property is currently developed with a 6-bedroom residence. The residence is served by an existing
OWTS. The original Garfield County Permit 0155 documented a 1000-gallon aerated treatment plant
(septic tank) followed by a 10’ x 10’ x 9’ drywell. The system was designed to accommodate 3 bedrooms.
The permit received final approval on August 20, 1975.
The septic tank was replaced with a 2000-gallon, two-compartment Valley Precast concrete septic tank in
October 2023. Garfield County Permit SEPT-8134 documents the replacement.
The residence is served potable water from a shared well located on a property to the southeast. We
researched nearby wells on the Colorado Division of Water Resources website and according to you, the
property owner, the shared well is located further south and east. The well location should be verified
prior to construction to assure the well is greater than 50-feet from the proposed septic tank and
greater than 100-feet from the proposed soil treatment area (STA).
Page 2
A ditch also runs along the eastern property boundary. The STA must be at least 50-feet from any open
portion of the ditch.
The proposed soil treatment area (STA) location is a relatively flat yard area to the south of the
residence.
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.
SUBSURFACE
The subsurface was investigated on October 13, 2023 when excavation for the septic tank was occurring.
The excavation location is labeled as TP1 (Test Pit #1) on the site plans. A visual and tactile soil analysis
was completed by Carla Ostberg at the time of excavation.1
The materials encountered in the septic tank excavation consisted of light brown loamy sand and cobbles
(greater than 35%) to a maximum depth explored of 9.0-feet. No bedrock or groundwater was
encountered.
We have researched soils in the area through USGS Web Soil Survey. The report is enclosed. The area of
the proposed STA is identified by map unit symbol 13. The map unit name is Atencio-Azeltine, 3 to 6%
slopes. Typical soil profile from 0 to 10 inches is sandy loam, 10 to 20 inches is sandy clay loam, 20 to 30
inches is gravelly sandy loam, and 30 to 60 inches consists of very gravelly sand. Depth to water table is
noted as greater than 80 inches.
The soil is consistent with R-0 (Soil Type 1 with more than 35% rock.) A pressure-dosed, unlined sand
filter with a minimum of 3-feet of sand filter material (Secondary Sand) is proposed. A long-term
acceptance rate (LTAR) of 0.8 gallons per square foot will be used to design the STA.
1 Carla Ostberg holds a Certificate of Attendance and Examination from the CPOW Visual and Tactile
Evaluation of Soils Training.
Page 3
DESIGN SPECIFICATIONS The existing drywell will need to be located and access gained for pumping any liquid. The remaining
void must be filled with onsite material.
The existing septic tank will remain in use.
Design Calculations:
Average Design Flow = 75 GPD x 2 people/bedroom x 3 Bedrooms + 225 GPD (4th, 5th and 6th Bedrooms) =
675 GPD
Min. 1350 gallons for 48-hour retention time (septic tank)
LTAR = 0.8 GPD/SF
675 GPD / 0.8 GPD/SF = 843.75 SF
The OWTS design is based on 6-bedrooms. An average daily wastewater flow of 675 GPD will be used.
For the purposes of this OWTS design, Benchmark Elevation has been established as the outlet invert of
the existing septic tank as 100’. The elevation of the outlet invert is approximately 48” below native grade
(32” of risers on top of 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
Automatic Distributing Valve Approximate horizontal distance 60’ / min. 1% rise /
min. 7.5” rise
Infiltrative Surface Approximate horizontal distance 8’ / min. 1% fall to
STA / min. 1” 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.
An Orenco® Biotube Pump Vault and an Orenco® PF5005 pump must be installed in the second
compartment of the existing septic tank. The floats should be set to dose approximately 70 gallons each
pump cycle, allowing approximately 6 gallons of drain back. The control panel for the pump must be
located within line of sight of the septic tank. An electrician will be responsible for wiring the pumping system
and the contractor will be responsible for connecting the plumbing. This office should be contacted for start-
up of the system to verify its functioning and to perform a squirt test prior to use of the system.
Pump Table
Dose Range Max = 174.75 gal. (675 GPD x
25% + 6 gallons drain back)
Min. 64 gal. (14.5 gal x 4) + 6 gal
drain back
Dose Setting 85 gallons/dose 6 gallons drain back (60’ / 1.5”
diameter pump line)
Float Separation 2000 gallon 2-compartment
Valley Precast concrete septic
tank
5” on/off float separation
Pump Criteria 29.2 gallons per minute (GPM) 21.8 feet total dynamic head
(TDH)
Effluent will be pumped through a 1.5-inch diameter pump line from the pump chamber to an Orenco®
automatic distributing valve (ADV), model 6402. This pump line must have a minimum 1% grade for proper
drain back into the tank after each pump cycle. The ADV must be placed at a high point in the system in an
insulated riser with access from grade. Screened rock must be placed below the ADV to support the ADV
and to assure the clear pipes exiting the ADV remain visible for future inspection and maintenance.
Page 4
Effluent will be pressure dosed to through 1.5-inch diameter distribution lines to a 13’ x 65’ bed. A minimum
of 3-feet of sand filter material will be installed in the over-excavated footprints. Sand filter material must be
clean, coarse sand, all passing a screen having four meshes to the inch. The sand must have an effective
size between 0.15 and 0.60 mm. The uniformity coefficient must be 7.0 or less. Material meeting ASTM 33,
for concrete sand, with three percent or less fines passing 200 mesh sieve may be used. A gradation of
the sand media must be submitted to this office prior to obtaining the sand.
Laterals must be 1.5-inches in diameter with 5/32-inch diameter orifices facing down, spaced 2-feet on
center, installed on the GeoMat™ with the filter fabric over the laterals. Laterals should be placed 2-feet
from the edges of the bed with 3.0-feet between the laterals. Laterals will be connected with 1.5-inch
diameter level manifolds. Four 39” wide GeoMats™ must be placed on the 13-foot wide bed. All material
associated with the GeoMat™ installation must be proprietary products associated with the GeoMat™,
including orifice shields and geotextile fabric. Manufacturer instructions must be followed regarding
installation of the GeoMat™.
Each 1.5-inch diameter lateral must end in a sweeping ell facing up with a ball valve for flushing. Valves
should be placed in a 10-inch sprinkler box for access. Laterals must be covered by a soil separation
fabric and at least 1-foot of topsoil or other suitable soil able to support vegetative growth. There shall be no
cobble-sized (>2.5”) or greater rock in final cover over the GeoMat™. Inspection ports must be placed at
each corner of each bed. Ports may be cut to grade and covered with a valve box 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
Pump Orenco® PF500511 ½ HP
120 Volt
Biotube ProPak Pump Package Orenco® BPP30DD Vault, Filter, Control Panel (demand dose) ADV Orenco® V6402A 1.5” Inlet and Outlets
ADV Riser and Lid Orenco® Double-walled PVC Risers
and Lids (30” diameter) Flushing Assembly Orenco® 1.5” diameter (2) 45° or 90° long sweep only (4 total) GeoMat™ GeoMatrix Systems, LLC 39” wide sheets 260’ GeoMat™ (39”) and 80 Orifice Shields
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 5
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 6
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
Pump Selection for a Pressurized System - Single Family Residence Project
40 Pine Street
Parameters
Discharge Assembly Size
Transport Length Before Valve
Transport Pipe Class
Transport Line Size
Distributing Valve Model
Transport Length After Valve
Transport Pipe Class
Transport Pipe Size
Max Elevation Lift
Manifold Length
Manifold Pipe Class
Manifold Pipe Size
Number of Laterals per Cell
Lateral Length
Lateral Pipe Class
Lateral Pipe Size
Orifice Size
Orifice Spacing
Residual Head
Flow Meter
'Add-on' Friction Losses
2.00
60
40
1.50
6402
8
40
1.50
4
3
40
1.25
4
63
40
1.50
5/32
3
5
None
0
inches
feet
inches
feet
inches
feet
feet
inches
feet
inches
inches
feet
feet
inches
feet
Calculations
Minimum Flow Rate per Orifice
Number of Orifices per Zone
Total Flow Rate per Zone
Number of Laterals per Zone
% Flow Differential 1st/Last Orifice
Transport Velocity Before Valve
Transport Velocity After Valve
0.68
44
29.9
2
3.1
4.7
4.7
gpm
gpm
%
fps
fps
Frictional Head Losses
Loss through Discharge
Loss in Transport Before Valve
Loss through Valve
Loss in Transport after Valve
Loss in Manifold
Loss in Laterals
Loss through Flowmeter
'Add-on' Friction Losses
1.8
3.1
6.9
0.4
0.1
0.4
0.0
0.0
feet
feet
feet
feet
feet
feet
feet
feet
Pipe Volumes
Vol of Transport Line Before Valve
Vol of Transport Line After Valve
Vol of Manifold
Vol of Laterals per Zone
Total Vol Before Valve
Total Vol After Valve
6.3
0.8
0.2
13.3
6.3
14.4
gals
gals
gals
gals
gals
gals
29.9
21.8
gpm
feet
0 1020304050607080
0
20
40
60
80
100
120
140
160
Net Discharge (gpm)
PumpData
PF5005 High Head Effluent Pump
50 GPM, 1/2HP
115/230V 1Ø 60Hz, 200/230V 3Ø 60Hz
PF5007 High Head Effluent Pump
50 GPM, 3/4HP
230V 1Ø 60Hz, 200/230/460V 3Ø 60Hz
PF5010 High Head Effluent Pump
50 GPM, 1HP
230V 1Ø 60Hz, 200/460V 3Ø 60Hz
PF5015 High Head Effluent Pump
50 GPM, 1-1/2HP
230V 1Ø 60Hz, 200V 3Ø 60Hz
Legend
System Curve:
Pump Curve:
Pump Optimal Range:
Operating Point:
Design Point:
Garfield County Public Health
2014 Blake Ave.
Glenwood Springs,CO 81601
Phone:970)945 6614 ext.8150
For inspections,call:970 945 6614 ext.8150 and call the Design Engineer,if applicable.
Project Address:40 Pine Street,Carbondale,CO 81623 Parcel No.:239328412005
Owner Name:Eryn Barker and Brian Long Owner Phone:503)998 5046
Contractor:Alpha Excavation,LLC Contractor Phone:970)471 6292
Number of Bedrooms 6__Minimum Tank Capacity 1,750_gal__Minimum Absorption_
OWTS PERMIT
KEEP AVAILABLE AT PROJECT SITE
Permit Number SEPT 8314_
Permit Type X New X Repair X Remodel/addition X Tank only
Issue Date 10/02/2023 Expiration Date 10/02/2024
Permit Conditions:
This OWTS Permit is approved on the condition of compliance with the application and scope of
work as submitted by Alpha Excavation,LLC via email dated September 19,2023.Changes must be
approved by Garfield County Public Health and the designer prior to construction.
A failing septic tank at the property will be replaced with a 2,000 gallon Valley Precast concrete
septic tank.The specified tank is on the Colorado Department of Public Health and Environment
CDPHE)approved septic tank list for OWTS installations.Risers on the tank access ports shall
provide access to grade for the tank.An effluent filter shall be installed on the outlet tee in the
second compartment of the tank.Contractor/designer shall ensure setback requirements in current
Garfield County OWTS Regulations are met.
Contact Garfield County Public Health at least 48 hours prior to requesting final inspection of the
installed system prior to backfill.NO OWTS COMPONENT SHALL BE BACKFILLED WITHOUT PRIOR
APPROVAL FROM GARFIELD COUNTY PUBLIC HEALTH AND THE DESIGNER.
Agreement
All installations must comply with all requirements of the Garfield County OWTS regulations
including but not limited to the conditions specified above.
In consideration of the issuance of the permit,the applicant hereby agrees to comply with all
laws and regulations related to the zoning,location,construction and erection of the proposed
OWTS and associated structures for which this permit is granted.The applicant further agrees
that if the above said regulations are not fully complied with in the zoning,location,erection
and construction of the above described OWTS and structure,the permit may then be revoked
by notice from the Health Department and immediately become null and void.
The issuance of a permit and specifications of terms and conditions therein will not constitute
assumption of liability,nor create presumption that the local public health agency or its
employees may be liable for the failure or malfunctioning of any system.Permit issuance will
not constitute a certification that the system,the equipment used in the system,or any
component used for system operation will ensure continuous compliance with the provision of
the OWTS Act,the regulations adopted thereunder,or any terms and conditions of a permit.
Permit Approval
Plans and specifications for the proposed OWTS have been reviewed and are considered
satisfactory.Permission is hereby given to the property owner(s)to perform the work indicated
in accordance with the Garfield County OWTS Regulation.This Permit will expire 1 year from
the date of issuance unless construction on the system has commenced.An as built"drawing
must be submitted and inspection of the system must be completed by GCPH before final
approval of the system will be issued.
10/02/2023
Issued By:Garfield County Environmental Health
Department
Date
9/7/2021 qPublic.net - Garfield County, CO - Property Record Card: R090012
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Gar eld County, CO
View Map
CARNEY, JENNIFER C
2610 FOOTHILL ROAD
SANTA BARBARA CA 93105
Building #1
Units 1
Building Type SFR
Abstract Codes / (Property Type)SINGLE FAM.RES-IMPROVEMTS-1212 (RESIDENTIAL PROPERTY)
Architectural Style BI LEVEL
Stories 1
Frame WOOD FRAME
Actual Year Built 1975
Basement Area 880
Finish Basement Area 880
Gross Living Area 944
Total Heated SqFt 1,824
Bedrooms 2
Baths 1.5
Heating Fuel ELECTRIC
Heating Type ELEC BS BD
Air Conditioning NONE
Roof Type GABLE
Roof Cover CORG METAL
Assessed Year 2021 2020 2019
Land Actual $220,000.00 $190,000.00 $190,000.00
Improvement Actual $347,040.00 $372,460.00 $372,460.00
Total Actual $567,040.00 $562,460.00 $562,460.00
Assessed Year 2021 2020 2019
Land Assessed $15,730.00 $13,590.00 $13,590.00
Improvement Assessed $24,810.00 $26,630.00 $26,630.00
Total Assessed $40,540.00 $40,220.00 $40,220.00
Tax Year 2020 2019 2018 2017
Taxes Billed $3,036.64 $3,063.68 $2,548.08 $2,435.60
Click here to view the tax information for this parcel on the Gar eld County Treasurer's website.
Summary
Account R090012
Parcel 239328412005
Property
Address
40 PINE ST, CARBONDALE, CO 81623
Legal
Description
Section: 28 Township: 7 Range: 88 Subdivision: COOPERTON TWNSTE.
Block: 12 Lot: 21 THRU:- Lot: 24
Acres 0
Land SqFt 15,750
Tax Area 9
Mill Levy 75.5010
Subdivision COOPERTON TWNSTE.
Owner
Land
Unit Type SINGLE FAM.RES.-LAND - 1112 (RESIDENTIAL PROPERTY)
Square Feet 15,750
Buildings
Actual Values
Assessed Values
Tax History
9/7/2021 qPublic.net - Garfield County, CO - Property Record Card: R090012
https://qpublic.schneidercorp.com/Application.aspx?AppID=1038&LayerID=22381&PageTypeID=4&PageID=9447&Q=1686460126&KeyValue=R090012 2/3
Sale Date Deed Type Reception Number Book - Page Sale Price
10/1/1996 Deeds 0994-0779 $0
2/14/1994 SUPPLEMENTAL AFFIDAVIT 0894-0478 $0
10/21/1993 Deeds 0894-0479 $0
2/8/1991 Deeds 0798-0753 $0
8/14/1985 Deeds 0673-0955 $0
9/7/1983 Deeds 0635-0130 $0
1/1/1900 Deeds 0481-0881 $0
Transfers
Photos
Sketches
9/7/2021 qPublic.net - Garfield County, CO - Property Record Card: R090012
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Version 2.3.145
The Gar eld County Assessor's Of ce makes every effort to produce the most accurate information possible. No warranties, expressed or
implied are provided for the data herein, its use or interpretation. Data is subject to constant change and its accuracy and completeness
cannot be guaranteed.
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Last Data Upload: 9/7/2021, 12:13:39 AM
Developed by
Garfield County, CO
Developed by
Account Number R090012
Par cel Number 239328412005
Acr es 0
Land SqFt 15,750
T ax Ar ea 009
2019 Mill Levy 75.5010
Physical Address 40 PINE ST
C ARBONDAL E 81623
Owner A ddr ess C ARNEY, JENNIFER C
2610 FO O THIL L RO AD
SANTA BARBARA C A 93105
2019 T otal A ctual Va lue $567,040 Last 2 Sa les
Date Pr ice
10/1/1996 $0
2/14/1994 $0
Date created: 9/7/2021
Last Data Uploa ded: 9/7/2021 2:13:39 AM
230 ft
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Roa ds
Parcel/Account
Number s
Highw ays
Limited Access
Highwa y
Major Road
Loca l Roa d
Minor Road
Other Road
Ra mp
Ferry
Pedestria n Way
Owner Na me
Lakes & River s
County Boundar y
Line