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HomeMy WebLinkAboutEngineer's OWTS Design Plan129 Cains Lane Carbondale, CO 81623 970.309.5259 carla.ostberg@gmail.com March 12, 2024 Project No. C1759 Kylie Gonzalez kyliecgonzalez@gmail.com Subsurface Investigation and Onsite Wastewater Treatment System Design 7-Bedroom Residence 1359 CR 294 Garfield County, Colorado Kylie, CBO Inc. performed a subsurface investigation and completed an onsite wastewater treatment system (OWTS) design for the subject residence. The 5-acre property is located outside of Rifle, in an area where OWTSs and wells are necessary. Legal Description: Section: 10 Township: 6 Range: 93 TR IN NWSE 5 ACRES Parcel ID: 2177-104-00-008 SITE CONDITIONS The property is currently developed with a 4-bedroom residence. The residence is served by an existing OWTS documented by Individual Sewage Disposal System Permit 1822. The permit describes continued use of an “existing” septic tank and installation of a new soil treatment area (STA) sized to accommodate a 3-bedroom residence. The permit received final approval on September 7, 1990. A remodel is proposed and will result in 7-bedrooms. The residence will continue to be served by a private well on the property. We have approximated the well location on the west side of the driveway. The well is located greater than 50-feet from the proposed septic tank and greater than 100-feet from the proposed soil treatment area (STA). The proposed soil treatment area (STA) location has is relatively flat. The proposed area is vegetated with native grasses. Page 2 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. The site plan enclosed was created to the best of our ability with the resources available to us, including Google Earth images and Garfield County GIS information. The site plan is not the result of a survey, and the property owner is responsible for verifying accuracy of the plan and to assure all setbacks are met. We were not made aware of any easements on the property. SUBSURFACE The subsurface was investigated on September 8, 2022 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 light brown silt clay loam to a maximum depth explored of 7.0-feet. No bedrock or groundwater was encountered. The materials encountered in Test Pit #2 were consistent with those encountered in Test Pit #1. Test Pit #2 was excavated to a maximum depth explored of 7.0-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 between 1 and 2-inches before breaking. Soil structure shape was blocky and consistence was firm. Soil texture was smooth. 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 1 Carla Ostberg holds a Certificate of Attendance and Examination from the CPOW Visual and Tactile Evaluation of Soils Training. Page 3 Backfill Proposed STA Test Pit #2 Sieved sample Ribbon between 1 and 2-inches Page 4 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: [75 GPD x 2 people/bedroom x 3 Bedrooms + 150 GPD (4th and 5th Bedrooms)] = 600 GPD + [75 GPD x 2 people/bedroom x 2 bedrooms] = 300 GPD Average Design Flow = 600 GPD + 300 GPD = 900 GPD LTAR = 0.35 GPD/SF 900 GPD / 0.35 GPD/SF = 2571 SF x 0.8 (pressure dosed trenches) x 0.7 (chambers) = 1440 SF The OWTS design is based on 7-bedrooms. An average daily wastewater flow of 900 GPD will be used. For the purposes of this OWTS design, Benchmark Elevation has been established as 100’ at Finished Floor (FF). The sewer line exists the residence approximately 3-feet below FF. CBO Inc. should be notified of any discrepancies or problems with grade elevations of proposed components during installation of the OWTS. Elevations and component locations must be confirmed and staked prior to excavation. OWTS Component Minimum Elevation Primary Tank Inlet Invert Approximate horizontal distance 110’ / min. 2% fall / min. 27.5” fall (MAX DEPTH TO TOP OF TANK 4’) Automatic Distributing Valve Approximate horizontal distance 25’ / min. 1% rise / min. 3.125” rise Infiltrative Surface Approximate horizontal distance 50’ to furthest trench / min. 1% fall to STA / min. 6.25” 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 5 We recommend replacing the sewer line all the way to the house foundation to assure grade remains consistent at the minimum 2% fall to the septic tank. The sewer line must be 4-inch SDR-35 with a double-sweep clean out near the foundation and at least every 100-feet in length. Where the sewer line crossed the driveway, the sewer line must be Schedule 40 or the SDR-35 sewer line may be placed in a 6-inch diameter Schedule 40 conduit. The system installation will include a 2000-gallon, two-compartment Valley Precast concrete septic tank with an Orenco® Effluent Filter on the outlet followed by a 500-gallon, single-compartment Valley Precast concrete pump chamber with an Orenco® Biotube Pump Vault and an Orenco® PF3005 pump. The floats should be set to dose approximately 73 gallons each pump cycle, allowing approximately 2.5 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 = 227.5 gal. (900 GPD x 25% + 2.5 gal drain back) Min. 58.5 gal. (14 gal x 4) + 2.5 gal drain back Dose Setting 73 gallons/dose 2.5 gallons drain back (25’ / 1.5” diameter pump line) Float Separation 500 gallon single-compartment Valley Precast concrete pump chamber 7” on/off float separation Pump Criteria 18.5 gallons per minute (GPM) 18.9 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 6606. 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. Effluent will be pressure dosed through 1.5-inch diameter pipes to six gravelless chamber trenches, each 20 ‘Quick 4’ Plus Standard Infiltrator® chambers, for a total of 120 chambers and 1440 square feet of infiltrative area. There must be at least 4-feet of undisturbed soil between each trench. Effluent will be pressure dosed to 1.5-inch diameter laterals, which must be hung with zip ties from the underside of the chambers. Laterals will have 5/32-inch diameter orifices facing up, with the exception of the first and last orifices facing down for drainage. Orenco® Orifice Shields may be placed under each downward-facing orifice. The orifices must be placed 3-feet on center. Each lateral must end in a 90 degree ell facing up with a ball valve for flushing. Valves may be placed in a valve box, accessible from grade, for access. Inspection ports must be placed at the beginning and end of each trench. 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. Page 6 COMPONENT MANUFACTURER MODEL NO. Septic Tank Valley Precast Item # 2000T-2CP 2000-gallon, two- compartment concrete septic tank Effluent Filter Orenco® Full size 4-inch diameter filter Pump Chamber Valley Precast Item #500T-1CP-HH 500-gallon, single- compartment pump chamber with HH pump Pump Orenco® PF300511 ½ HP 120 Volt Biotube ProPak Pump Package Orenco® BPP30DD Vault, Filter, Control Panel (demand dose) Tank Risers and Lids Orenco® Double-walled PVC Risers and Lids (24” diameter) ADV Orenco® V6606A 1.5” Inlet and Outlets ADV Riser and Lid Orenco® Double-walled PVC Risers and Lids (30” diameter) Orifice Shields Orenco® OS150 1.5 inch diameter (12 total) Flushing Assembly Orenco® 1.5” diameter (2) 45° or 90° long sweep (6 total) Chambers Infiltrator® ‘Quick 4’ Plus Standard 120 ‘Quick 4’ 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. 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), Page 7 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. 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. Page 8 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 1359 CR 294 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 1.25 25 40 1.50 6606 50 40 1.50 3 0 40 1.50 6 80 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 27 18.5 1 5.5 2.9 2.9 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 2.4 0.5 6.3 1.1 0.0 0.6 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 2.6 5.3 0.0 8.5 2.6 13.7 gals gals gals gals gals gals 18.5 18.9 gpm feet 0 5 10 15 20 25 30 35 40 0 50 100 150 200 250 300 Net Discharge (gpm) PumpData PF3005 High Head Effluent Pump 30 GPM, 1/2HP 115/230V 1Ø 60Hz, 200V 3Ø 60Hz PF3007 High Head Effluent Pump 30 GPM, 3/4HP 230V 1Ø 60Hz, 200/460V 3Ø 60Hz PF3010 High Head Effluent Pump 30 GPM, 1HP 230V 1Ø 60Hz, 200/460V 3Ø 60Hz PF3015 High Head Effluent Pump 30 GPM, 1-1/2HP 230V 1Ø 60Hz, 200/230/460V 3Ø 60Hz Legend System Curve: Pump Curve: Pump Optimal Range: Operating Point: Design Point: W TH E L O C A T I O N O F P R O P O S E D I M P R O V E M E N T S S H O W N A R E NO T T H E R E S U L T O F A P R O P E R T Y S U R V E Y . T H E L O C A T I O N S AR E A P P R O X I M A T E . I T I S T H E H O M E O W N E R S ' D U T Y T O EN S U R E A L L C O N S T R U C T I O N A N D I M P R O V E M E N T L O C A T I O N S AR E A C C U R A T E . P R O P E R T Y L I N E S A N D S E T B A C K D I S T A N C E S SH O U L D B E C O N F I R M E D P R I O R T O E X C A V A T I O N . S C A L E D FO R P R I N T I N G O N 1 1 " X 1 7 " P A P E R . PR O P E R T Y L I N E 7- B E D R O O M RE S I D E N C E ST A SH O P DR I V E W A Y TP 1 TP 2 WE L L C O U N T Y R O A D 2 9 4 SE P T I C TA N K BA R N FE N C E 50 ' 10 0 ' We s t e r l i n / G o n z a l e s R e s i d e n c e 13 5 9 C R 2 9 4 Ga r f i e l d C o u n t y , C o l o r a d o Pr o j e c t N u m b e r : C 1 7 5 9 Da t e : 0 3 / 1 2 / 2 0 2 4 De s i g n e d b y : C B O Re v i e w e d b y : K C Dr a w n b y : D D Sh e e t 1 0 F 4 W1 . 0 DR A W I N G S M U S T B E U S E D I N CO N J U N C T I O N W I T H D E S I G N LE T T E R D A T E D 0 3 / 1 2 / 2 0 2 4 CB O I n c . 12 9 C a i n s L a n e Ca r b o n d a l e , C o l o r a d o 8 1 6 2 3 Ph o n e 9 7 0 . 3 0 9 . 5 2 5 9 ca r l a . o s t b e r g @ g m a i l . c o m N SC A L E : 1 = 5 0 ' = 0 " 1359 CR 294 Legend 1359 Co Rd 294 300 ft N ➤➤ N Image © 2024 A ir bus Image © 2024 A irbus Image © 2024 A irbus Garfield County, CO Developed by Account Number R210354 Par cel Number 217710400008 Acr es 5 Land SqFt 0 T ax Ar ea 021 2019 Mill Levy 74.6820 Physical Addr ess 1359 294 C O UNTY RD RIFL E 81650 O w ner Addr ess WESTERL IND, LUC INDA & DON O & GONZALEZ, 1359 C OUNTY ROAD 294 RIFL E C O 81650 2019 T otal Actual V alue $678,270 Last 2 Sa les Date Pr ice 3/15/2019 $635,000 7/1/2016 $0 Date created: 7/12/2022 Last Data Uploa ded: 7/12/2022 2:48:51 AM 460 ft Overvi ew Legend Parcels 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 7/12/22, 1:04 PM qPublic.net - Garfield County, CO - Property Record Card: R210354 https://qpublic.schneidercorp.com/Application.aspx?AppID=1038&LayerID=22381&PageTypeID=4&PageID=9447&Q=864265657&KeyValue=R210354 1/3 Gareld County, CO View Map WESTERLIND, LUCINDA & DON O & GONZALEZ, 1359 COUNTY ROAD 294 RIFLE CO 81650 Building #1 Units 1 Building Type SFR Abstract Codes / (Property Type)SINGLE FAM.RES-IMPROVEMTS-1212 (RESIDENTIAL PROPERTY) Architectural Style 1-STRY/BSM Stories 1 Frame WOOD FRAME Actual Year Built 1981 Basement Area 2,274 Gross Living Area 3,810 Total Heated SqFt 3,810 Bedrooms 4 Baths 3 Heating Fuel ELECTRIC Heating Type ELEC BS BD Air Conditioning CENTRAL Roof Type GABLE Roof Cover COMP SHNGL Assessed Year 2022 2021 2020 Land Actual $120,000.00 $120,000.00 $160,000.00 Improvement Actual $558,270.00 $558,270.00 $527,260.00 Total Actual $678,270.00 $678,270.00 $687,260.00 Assessed Year 2022 2021 2020 Land Assessed $8,340.00 $8,580.00 $11,440.00 Improvement Assessed $38,800.00 $39,920.00 $37,700.00 Total Assessed $47,140.00 $48,500.00 $49,140.00 Tax Year 2021 2020 2019 2018 Taxes Billed $3,622.08 $3,335.76 $3,142.88 $3,155.88 Click here to view the tax information for this parcel on the Gareld County Treasurer's website. Summary Account R210354 Parcel 217710400008 Property Address 1359 294 COUNTY RD, RIFLE, CO   81650 Legal Description Section: 10 Township: 6 Range: 93 TR IN NWSE 5 ACRES Acres 5 Land SqFt 0 Tax Area 21 Mill Levy 74.6820 Subdivision Owner Land Unit Type SINGLE FAM.RES.-LAND - 1112 (RESIDENTIAL PROPERTY) Square Feet 0 Buildings Actual Values Assessed Values Tax History 7/12/22, 1:04 PM qPublic.net - Garfield County, CO - Property Record Card: R210354 https://qpublic.schneidercorp.com/Application.aspx?AppID=1038&LayerID=22381&PageTypeID=4&PageID=9447&Q=864265657&KeyValue=R210354 2/3 Sale Date Deed Type Reception Number Book - Page Sale Price 3/15/2019 WARRANTY DEED 918178  $635,000 7/1/2016 DEATH CERTIFICATE 897192  $0 8/2/2004 RESOLUTION 657206 1610-638 $0 8/2/2004 RESOLUTION 657205 1610-634 $0 10/12/1999 WARRANTY DEED 553584 1155-85 $244,000 2/17/1995 DEED OF DISTRIBUTION 474678 0932-0298 $0 2/17/1995 LETTERS 474677 0932-0297 $0 2/13/1995 SUPPLEMENTAL AFFIDAVIT 474676 0932-0296 $0 2/3/1995 DEATH CERTIFICATE 474675 0932-0295 $0 8/7/1993 QUIT CLAIM DEED 451250 0872-0315 $0 5/11/1982 QUIT CLAIM DEED 327879 0599-0785 $0 8/27/1981 WARRANTY DEED 318761 0580-0499 $0 Click here to view Property Related Public Documents Transfers Property Related Public Documents Photos Sketches 7/12/22, 1:04 PM qPublic.net - Garfield County, CO - Property Record Card: R210354 https://qpublic.schneidercorp.com/Application.aspx?AppID=1038&LayerID=22381&PageTypeID=4&PageID=9447&Q=864265657&KeyValue=R210354 3/3 Version 2.3.206 The Gareld County Assessor's Ofce makes every effort to produce the most accurate information possible. 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