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Home My WebLink AboutOWTS Design129 Cains Lane Carbondale, CO 81623 970.309.5259 carla.ostberg@gmail.com December 2, 2021 Project No. C1684 Dan Dixon dan@custom-works.biz Subsurface Investigation and Onsite Wastewater Treatment System Design 3-Bedroom Residence + Future 1-Bedroom Accessory Dwelling Unit (ADU) 2395 Hwy 133 Garfield County, Colorado Dan, CBO Inc. performed a subsurface investigation and completed an onsite wastewater treatment system (OWTS) design for the subject residence. The 0.33-acre property (per April 3, 2019 Divide Creek Survey, Inc. survey, enclosed) located outside of Carbondale, in an area where OWTSs are necessary. Legal Description: Section: 3 Township: 8 Range: 88 A TR IN LOT 16. Parcel ID: 2463-034-00-002 SITE CONDITIONS A 3-bedroom, single-family residence and detached shop (with no bedrooms) presently exists on the property. The residence and shop are currently served by an existing OWTS. Garfield County Individual Sewage Disposal System Permit 2130 documents this system. The system consists of a 1000-gallon, 2- compartment Norwesco® poly septic tank followed by a gravelless chamber bed consisting of 4 rows of 1 and 1 row of 4 ‘Standard’ Infiltrator® chambers for a total of 24 chambers and 450 square feet of infiltrative area. The permit received final approval from Garfield County on August 16, 1993. The system was sized to accommodate 2 bedrooms. The septic tank is in poor condition and soil treatment area (STA) is slow draining. There is a desire to upgrade the OWTS. The property is currently served potable water from the Town of Carbondale. The water line enters the property from the east. The water line will not come within 25-feet of any proposed OWTS component. The Carbondale Town Ditch runs along the western property boundary. This ditch has been placed in a culvert. The STA must be located at least 10-feet from the ditch and any property line. The proposed soil treatment area (STA) location is relatively flat. The proposed area is located in a yard currently vegetated with native grasses. We recommend limited irrigation to re-establish vegetation after installation of the STA. 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 July 14, 2018 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 (excavated near the ditch) consisted of medium brown loam to a maximum depth explored of 5-feet. No bedrock or groundwater was encountered. The materials encountered in Test Pit #2 (excavated near the residence) consisted of medium brown loam to a maximum depth explored of 6-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 approximately 1-inch in length before breaking. Soil structure shape was blocky and consistence was friable to firm. Soil texture was both gritty and smooth. STA sizing is based on Soil Type 2, Loam with moderate structure grade. Due to space constraints, an over-excavated, unlined sand filter with a 2-feet of Secondary Sand Filter material is proposed. A long term acceptance rate (LTAR) of 0.8 gallons per square foot will be used to design the OWTS, in accordance with Garfield County On-Site Wastewater Treatment System Regulations. 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 View of Test Pit #1 Test Pit #2 Backfill Page 4 Sieved sample DESIGN SPECIFICATIONS The existing septic tank will be pumped and removed, and the existing STA will be abandoned in place. Design Calculations: Average Design Flow = 75 GPD x 2 people/bedroom x 4 Bedrooms = 600 GPD LTAR = 0.8 Gal/SF 600 GPD / 0.8 = 750 SF The new OWTS design is based on 4-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 sewer line exiting the residence. 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 34’ from Shop and 9’ from residence / min. 2% fall / min. 8.5” fall from Shop and 2.25” fall from residence Automatic Distributing Valve Approximate horizontal distance 7’ / min 1% rise for drain back / min. 0.875” rise Infiltrative Surface Approximate horizontal distance 11’ / min. 1% fall / min. 1.375” fall *Elevations are based upon standard OWTS installation practices. Component elevations may change during installation due to site conditions. The plumbing will be re-routed through the crawl space in the residence to exit at a higher elevation and slightly different location than the existing sewer line. This scope of work will be completed by a plumber. A new, 4-inch diameter SDR-35 sewer line must have a minimum 2% fall to the septic tank. The existing sewer line serving the existing shop (future ADU) will be routed to connect to the sewer line from the residence, prior to entering the septic tank, with a wye fitting OR can be brought into the inlet side of the septic tank through the knock-out. Page 5 A new 1500-gallon, two-compartment Valley Precast concrete septic tank will be installed with an Orenco® ProPak and an Orenco® PF3005 pump in the second compartment of the septic tank. Risers must be installed on the septic tanks to bring access to grade. The floats should be set to dose approximately 55 gallons each pump cycle, allowing approximately 1 gallon of drain back after each pump cycle. Handle extensions on both the effluent filter and float tree must be installed if the riser height exceeds 1-foot. The control panel must be located within line of sight of the septic tanks. We recommend Valley Precast out of Buena Vista be contracted for start-up of the pumping system. Pump Table Dose Range Max = 151 gal. (600 GPD x 25% + 1 gal drain back) Min. 45 gal. (11 gal x 4) + 1 gal drain back Dose Setting 55 gallons/dose 1 gallons drain back (7’ / 1.5” diameter pump line) Float Separation 1500 gallon two-compartment poly pump chamber 5.5” on/off float separation Pump Criteria 28.8 gallons per minute (GPM) 22 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. In this case, with the relatively flat topography, the pump line may exit the septic tank rather than the riser. The ADV must be placed at a high point 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 distribution lines to two zones in a 12’ x 62.5’ bed. A minimum of 2-feet of sand filter material will be installed in the over-excavated footprint. 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 will be connected with 1.5-inch diameter level manifolds. Laterals used to disperse the effluent must be surrounded by washed coarse screened gravel or crushed stone (minimum 6-inches below and minimum 2-inches above laterals). All of the gravel or stone must pass a 2 ½-inch screen and must be retained on a ¾-inch screen. Laterals must be 1.5-inches in diameter with 5/32-inch diameter orifices facing down, spaced 3-feet on center (OC). We recommend Orenco® Orifice Shields be installed on the laterals at each orifice. Laterals will begin 2-feet from the edges of the filter, with 2-feet between the middle laterals and 3- feet between the laterals that are connected with the manifold (see W3.0/1 STA Plan). Each 1.5-inch diameter lateral must end in a sweeping ell facing up with a ball valve for flushing. A soil separation fabric should be placed over the gravel layer followed by approximately 1-foot of topsoil or other suitable soil able to support vegetative growth. Inspection ports must be placed in each corner of the bed. 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. COMMENTS Septic Tank Valley Precast Item # 1500T-2CP-HH 2-compartment concrete septic tank with high head 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® V6402A 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 (80 total) Flushing Assembly Orenco® 1.5” diameter (2) 45° or 90° long sweep (4 total) Construction must be according to Garfield County On-Site Wastewater Treatment System Regulations, the OWTS Permit provided by Garfield County Building Department, and this design. 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. Page 7 12-13-2021 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. Sincerely, CBO Inc. Reviewed By: Carla Ostberg, MPH, REHS Romeo A. Baylosis, PE Pump Selection for a Pressurized System - Single Family Residence Project 2395 Hwy 133 / Dixon Residence 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 7 40 1.50 6402 11 40 1.50 3 3 40 1.50 4 60.5 40 1.25 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 42 28.8 2 5.6 4.6 4.6 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 5.8 0.3 6.6 0.5 0.0 0.7 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 0.7 1.2 0.3 9.4 0.7 10.9 gals gals gals gals gals gals 28.8 22.0 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: 2395 Hw y 133 Legend R090002 100 ft N➤➤N Iii 1 11 r GARFIELD COUNTY BUILDING AND SANITATION DEPARTMENT Permit N 2 1 3 Q 109 8th Street Sulte 303 Assessor's Parcel No.1, Glenwood Springs, Colorado 61601 r Phone (903) 945-8212 This does not constitute INDIVIDUAL SEWAGE DISPOSAL PERMIT a building or use permit.i PROPERTY f a Owner's Name Vera A . Arbana Present Address 0028 Chalyn Rd . Glacn000dhone 945 -7271 System Location 2395 Highway 133, Carbondale Legal Description of Assessor's Parcel No. SYSTEM DESIGN 7 - 1)Septic Tank Capacity (gallon)Other A r' ' 3 >Percolation Rate (minutes /inch Number of Bedrooms (or other) is IAA J /2* ' X Required Absorption Area - See "k ° ^A°^ 1.1 '/ y 1 /+(, es'c. +- - is [-Ti !4> " p f ` g, r r FSpecialSetbackRequirements:H 7 F7 ' iV r2 f T° /t r 6Y °5 P ''ti1 ry- e,, I ` v H p Nk717 C'07itAc1'Oy S;'.5 r ,,,. 27 a Date 7 ° 93 Inspector'01 C 0.AAYtiM FINAL SYSTEM INSPECTION AND APPROVAL (as installed) Call for Inspection (24 hours notice Before Covering Installation E System Installer nom".` ' ll ` 1" Co Septic Tank Capacity I Q 0 I/Septic Tank Manufacturer or Trade Name Y 0 Y' IN es C O f_- fn-c Septic Tank Access within 8" of surface Absorption Area 171 •/ 7 PI io-tA'a cA c — I 19n-t r'- rk rl _{.. Absorption Area Type and /or Manufacturer or Trade Name 7' CU/ f/{.. , A' ATO'r Adequate compliance with County and State regulations/requirements Z.- Other Date $— 1c, - / 7 Inspector RETAIN WITH RECEIPT RECORDS AT CONSTRUCTION SITE CONDITIONS:P 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. Con- nection to or use with any dwelling or structures not approved by the Building and Zoning office shall automatically be a violation or 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 materialvariationtremthetermsorspecificationscontainedIntheapplicationofpermitcommitsaClassI, Petty Offense ($500.00 fine — 8 months in )e orbptI')n w u,(, r Applloent +Qr on toy Department Pink COpy Application INDIVIDUAL SEWAGE DISPOSAL SYSTEM APPLICATION Approval by County Official: OWNER V644/ A, ARBANEY 90 P ADDRESS (9•28 G//ELyN RD 61b3 Go.11€01 PHONEem 57#7ay CONTRACTOR__SG' /ILrf PHONE 9a' ^7ADDRESS PERMIT REQUEST FOR: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 pa 4.) LOCATION OF PROPOSED FACILITY: County 6,irfle Near what City of Town(,o.,laho)1dale.Lot SizeAro/ 96 X/6 Legal Descriptions 1 .'.•. r er fi S ma k /,1 ?sr enakaya Arti/N. WASTES TYPE:C ) Dwelling Transient Use Commercial or Institutional Non- domestic Wastes Other - Describe BUILDING OR SERVICE TYPE: / 'es'i c e- Number of bedrooms par)Number of persons* PL Garbage grinder x) Automatic washer Dishwasher SOURCE AND TYPE OF WATER SUPPLY: well spring stream or creek Give depth of all wells within 180 feet of system: If supplied by community water, give name or supplier: ems' ,viiOrna- GROUND CONDITIONS: Depth to bedrock: Depth to first Ground Water Table: 7/Z Ff Percent ground slope: £q5 /Go/.O filed- DISTANCE TO NEAREST COMMUNITY SEW SYSTEM: Al /Cant bat Was an effort made to connect to community system?D TYPE OF INDIVIDUAL SEWAGE DISPOSAL SYSTEM PROPOSED: V) 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: ci Absorption Trench, Bed or Pit Evapotranspiration Underground Dispersal Sand Filter Above Ground Dispersal Wastewater Pond Other - Describe: WILL EFFLUENT BE DISCHARGED DIRECTLY INTO WATERS OF THE STATE? v0 SOIL PERCOLATION 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.__ Name, 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 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 permfti s'subject tosuchtermsandconditionsasdeemednecessarytoinsurecompliancewithrulesandregulations adopted under Article 10, Title 25, C.R.t. 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 niy knowledge and belief and are designed to be relied on by the local department of healthinevaluatingthesameforpurposesofissuingthepermitappliedforherein. 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 Signed 11 naiLas . IS- PLEASE DRAW AND ACCURATE MAP TO YOUR PROPEL ZS *Yy N 1"3q5 nar3 Cfri afia .Are w, e_. 3 vo A oy ca t Jondtat "W ,sf.GS of e_ 2 oS 1 Page Lvyy ys* Zr... PLOT PLAN AND DESIGN FEATURES: Include by measured distance location of wells, springs, potable water supply lines, cisterns, buildings, property lines, subsoil drains, lake, water course, stream, dry gulch and show location of proposed system by direction and distance from dwelling or other fixed reference object, and additional submissions in support of this application such as data, plans, specifications, statements and rnnmitmanter i CClt,dOy,G/a /e T c N 0o P lijr(n-CsueO E Q Ib q,o __ta, q 9 eft. s'w ._a , k As 1itt-!. 413 Iill —3°0 i 0 h i NI tin IN a y 1b sc- I - ,....„ Ziy pa. kA N01 saM Scti MIA Garfield County, CO Developed by Account Number R090002 Par cel Number 246303400002 Acr es 0 Land SqFt 0 T ax Ar ea 009 2019 Mill Levy 75.5010 Physical Addr ess 2395 133 HWY C ARBO NDALE 81623 O w ner Addr ess EATON DIXON, C ANDAC E D & DIXON, DANIEL P 2395 HIGHWAY 133 C ARBO NDALE C O 81623 2019 T otal Actual V alue $659,980 Last 2 Sa les Date Pr ice 5/25/2018 $0 5/25/2018 $424,000 Date created: 12/6/2021 Last Data Uploa ded: 12/6/2021 2:05:37 AM 58 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