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Home My WebLink AboutOWTS Design129 CAINS LANE CARBoNDALE, CO A1623 970.309.5259 c¡Rla. os-fn e Rc@c rr¿et l. c ol¿ !¡iltl>'l'I( : (l()l\S( I f -'l'IFÌ(; February 23,2022 Project No. C1692 Trevor Ruonavaara trevorruonavaara@hotmail. com Subsurface lnvestigation and Onsite Wastewater Treatment System Design 3-Bedroom Residence TBD CR 31 1 Garfield County, Colorado Trevor, CBO lnc. performed a subsurface investigation and completed an onsite wastewater treatment system (OWTS) design forthe subject residence. The 2.259-acre property is located outside of Silt, in an area where OWTSs and wells are necessary. Legal Description: Section: 12 Township: 7 Range: 92 A PCL OF LAND lN THE NWSE. AKA LOT 2 JOSEF P LANGEGGER SUB-DIV EXEMPTION Parcel lD: 2401 -124-00-263 SITE CONDITIONS The property is currently undeveloped. A 3-bedroom single-family residence is proposed A private well will serve the residence. The well has been drilled and is located near the center of the property, to the west of the proposed residence. The well will be greater than SO-feet from the proposed septic tank and greater than 1O0-feet from the proposed soil treatment area (STA). Any portion of sewer line that comes within SO-feet of the well will be encased (see W4.0/3 Encasement Detail). Divide Creek runs along the western property boundary. The creek was not identified in any site plan provided to us; therefore, we have estimated the location and route of the creek to the best of our ability using a Google Earth image. Divide Creek is greater than SO-feet from any OWTS component. The proposed soil treatment area (STA) location has an approximate I to 10 percent slope to the west toward Divide Creek. The proposed area is vegetated with native grasses. The area had snow cover at the time of our site visit. 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 -q&i:. SUBSURFAGE The subsurface was investigated on February 22,2022 by digging one soil profile test pit excavation (Test Pit). A visual and tactile soil analysis was completed by Carla Ostberg at the time of excavation.l Previous soil evaluations were conducted by HP Geotech (2007) and Kumar and Associates (2021). The materials encountered in Test Pit #1 consisted of medium brown sandy clay loam to a maximum depth explored of 8.0-feet. No bedrock or groundwater was encountered. A sample of the soils was taken from Test Pit #1 at 4-feet below grade. Soil structure grade was moderate. The soilformed a ball and a ribbon 1 to 2-inches in length before breaking. Soil structure shape was blocky and consistence was friable to firm. Soil texture was more gritty than smooth. 1 Carla Ostberg holds a Certificate of Attendance and Examination from the CPOW Visual and Tactile Evaluation of Soils Training. Page 3 HP Geotech performed a subsurface investigation and results are detailed in a report dated September 28,2007 , Project No. 107 0623 (enclosed). A Profile Pit was excavated, and three percolation tests were run. The Profile Pit consisted of 6-inches of topsoil, underlain by brown, moist to slightly moist, stiff to medium stiff, sandy to very sandy silty clay with occasional gravels and low plasticity. Percolation tests resulted in 60 minutes per inch (MPl). Kumar and Associates updated the soil study in a report date December 15, 2021, Prqect No. 21-7-923. Our findings onsite are consistent with previous subsurface evaluations. STA sizing is based on Soil Type 3, Sandy 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 OWTS. | ':& 'é;j* -:' j! "-t.,:*' _,,Jijlt* View of property Test Pit #1 Well *$ ,; .rÈ-- Page 4 -"' Sidewalls Backfill {¡.i{L.s- View from Test Pit toward Creek "t Page 5 Sample Ribbon DESIGN SPECIFICATIONS Desiqn 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 x 1.0 (gravity trenches) x 0.7 (chambers) - 900 SF The new OWTS design is based on 3-bedrooms. An average daily wastewater flow of 450 GPD will be used. For the purposes of this OWTS design, Benchmark Elevation has been established as 6164' Finished Floor (100'). CBO lnc. should be notified of any discrepancies or problems with grade elevations of proposed components during installation of the OWTS. *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. The 4-inch diameter SDR-35 sewer line exiting the residence must have a double-sweep clean out and a minimum 2o/o grade to the septic tank. The system installation must include a 1000-gallon, two-compartment septic tank (state-approved concrete or poly)with an effluent filter on the outlet tee. Risers must bring the manhole lids to grade for access. lf 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 five 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. OWTS Component Minimum Elevation Primary Tank lnlet lnvert Approximate horizontal distance 29' I min.2% fall I min. 7.25" fall Distribution Box Approximate horizontal distance 77' I min. 1% fall I min.9.625" fall lnfiltrative Surface Approximate horizontal distance to furthest trench 36' / min. 1o/o fall / min. 4.5" to furthest trench Page 6 Each trench will consist of 15 'Quick 4' Standard Plus lnfiltrator@ chambers for a total of 900 square feet of infiltrative area. There must be at least 4-feet of undisturbed soil between each trench. lnspection 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. GBO lnc. 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. 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 lnc. 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 offlce is expected throughout the installation. INSTALLATION OBSERVATIONS CBO lnc. 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 lnc. should be notified 48 hours in advance to observe the installation. ln 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. COMPONENT MANUFACTURER MODEL NO.COMMENTS Septic Tank Valley Precast or lnfiltrator@ tem # 1000T-2CP or tem # 1060-2CP 1000-gallon,2- oomoartment seotic tank Risers and Lids Orenco@ Double-walled PVC risers and lids Effluent Filter Orenco@ 4-inch diameter Full size Distribution Box Polylok Distribution box, lids, rises, and (5)flow equalizers Chambers lnflltratorG)standard Plus /5 'Quick 4' PageT 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 additionalwater 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. lf an effluent filter or screen has been installed in the OWTS, we recommend this fllter or screen be cleaned annually, or as needed. lf 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 CONSTRUGT¡ON NOTES lf 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. lf soil conditions encountered are different from conditions described in report, CBO lnc. 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. Page 8 Please call with questions. Sincerely, CBO lnc. Carla Ostberg, MPH, REHS (¿rn[a- }gtfu,^'E CBO lnc.129 Ca¡ns LaneCarbondale, CdoEdo 81623Phone 970.309.5259carla.ostberg@gma¡1.æmNoocz-{Foc,C"SCALE: I = 50'=0'I(t(\RESIDENCE\ISTA{,l\BCREEK(/--PROPERry LINETHE LOCATION OF PROPOSED IMPROVEMENTS SHOWN ARENOT THE RESULT OF A PROPERTY SURVEY. THE LOCATIONSARE APPROXIMATE. IT IS THE HOMEOWNERS' DUTY TOENSURE ALL CONSTRUCTION AND IMPROVÊMENT LOCATIONSARE ACCURATE. PROPERry UNES AND SETBACK DISTANCESSHOULD BE CONFIRMED PRIOR TO EXCAVATION. SCALEDFOR PRINTING ON 11" X 1T PAPER.DRAWINGS MUST BE USED INCONJUNCTION WITH DESIGNLETTER DATED 02123 12022lv2.0Ruonavaara ResidenceTBD CR 311Garfield County, ColoradoProject Number: C1692Date: 0212312022DesignedReviewedDrawn by:by: CBOby: RBDDw1 .0Sheet 1 0F 4 CBO lnc.129 Cains LaneCarbondale, Colorado 81623Phone 970.309.5259carla.ostberg@gmail.com+.vRuonavaara ResidenceTBD CR 31 1Garfield County, ColoradoProjectNumber: C1692Dale: O2l23nO22by: CBOby: RBDDDes¡gnedRèviewedDrawn by:lIIl\+),61BM(FF+3-BEDROOMRESIDENCESheet 2 0F 4w2.04'I((iI(.vN1 OOO-GALLON, TWO-COMPARTM ENTSCHEDULE 40 ENCASEMENT PIPEWITHIN 50'WELL SETBACK (SEEw4.0/3 ENCASEMENT DETATL)SEPTIC TANK WITH EFFLUENT SCREEN4" DIA SDR-35 SEWER PIPEWITH CLEANOUTMIN 2% FALL TO TANK/4' DIA SDR-35 PVC SEWER L|NE(MrN. 1% FALL TO D-BOX)L\SCALE:1"= 20'{"(*¡è\(4' DIA SDR.35 SEWER LINE TO EACH TRENCH(MrN. 1% SLOPE TO TRENCH)(CREEKTP1DISTRIBUTION BOXWITH ACCESS AT GRADE'OUICK4' CHAMBER TRENCHES.5 TRENCHES WTH 1 5 CHAMBERS PER TRENCHFOR A TOTAL OF 75 CHAMBERS AND900 sF.\\IIIjIi\\\I8-107o SLOPE4' DIA SDR-35 INSPECTION PORT ATBEGINNING AND END OF EACH TRENCH--_L\Iy'\NOTES:. TRENCHES MUST FOLLOWCONTOURS. LOCATION OF CREËK HAS BEENAPPROXIMATED AND IS NOT THERESULT OF A SURVEYLINE CBO lnc.129 Cains LaneCarbondale, Colorado 81ô23Phone 970.309.5259carla.ostberg@gmail.comI5 CHAMBERS PER RENCHf OIASDRSs DISTRIBUTIONLINE TO EACH TRENCH(MtN.'t% sLoPE TO TRENCH)END PLATEGMVELLESS'QUICK-4'CHAMBER (4'x3)4' DI,A SDR35 SEWERLINE FROM SEPTICTANKDISIRIBUTION BOXWTHACCESS AT GMDEDISTRIBUTION PIPESTO 4TH AND sTHTRENCHÊSDIA SDR-35INSPECTIONPORTPLACED IN4',TOP PORT OFCHAMBER ÊNOPUTESLsotLLIMITl4' DIA SDR.3S INSPECTIONPORTAT BEGINNING ANDEND OF ACH TRENCHEXCAVATION'outcK4'SCARIFYCHAMBER (4 x 3')/ì CHAMBER'TRENCH SECÎON\t¡-ffiSMALL VALVE COVERBOX OR IRRIGATIONVALVE BOX AT GRADEFINISHED GRADECAP OR THREADEDBOX AND COVER BROUGHT TO GRADECONCRETE LID----1\CLEANOUT ASSEMBLY24" MtN.COMPACT4' DIA SDR-35 SEWERffiããD-Ë-BASE TO SUPPORTBOX4'PVC PIPE CUTTOFIT(MIN 2% SLOPE TO TANK,MtN. 1olo TO STA)USE HOLE SAW TOCUT THRU TOP OFSCREENEDENDOR SAND FORBEDDING3'MIN.8'MIN,BAFFLE ORANGLED PIPE/âINSPECÎON PORT OETAIL\9'-TO BE USEDAT INLET/ãDISTRIEUTION BOX DET\e,r-AILOUTLETS[rooooRuonavaara ResidenceTBD CR 31 1Garfield County, ColoradoProjectNumber: C1692l>ao: o2t23t2o22loes¡gneo uy: ceolReviewed by: RBlDrawn bV: DDw3.0Sheet 3 0F 4 CBO lnc.129 Cains LâneCarbondale, Colorado 81623Phone 970.309.5259carla.ostberg@gmail.æmDESIGN3-AEDROOM RESIDENCESTA IO WATER COURSE50'77'STATO WELL100'106'STA TO HOUSE20'107'SEPTIC TANK TO WATER COURSE50'1 16'SEPTIC TANK TO WELL50'54',HOUSE TO SEPTIC TANK5'2TOWTS COMPONENTS ANDPHYSICAL FEATURESMINIMUM REQUIREDSETBACKAPPROXIMATE PROPOSEDSETBACK(75 GPD x 2 PERSONS/BEDROOM x 3 BEDROOMS)WASTEWATER FLOW = 450 GPDTANK:MIN. 1OOO GALLONSUSE lOOO-GALLON, TWO-COMPARTMENT SEPTIC TANKSOIL TREATMENT AREA (STA):LONG TERM ACCEPTANCE RATE (LTAR) = 0.35 GAU SFCALCULATED STA = C/LTAR = 450 / 0.35 = 1286 SFGRAVITY, TRENCHES = 1286 SF X 1.0 = 1286 SFCHAMBERS = 1286 SF X 0.7 = 900 SF / 12 SF / CHAMBER = 75 CHAMBERSFIVE GRAVELLESS CHAMBER TRENCHES15 'QUICK 4' CHAMBERS IN EACH TRENCHTOTAL 15 'OUICK 4' CHAMBERSSLIP.ON PVCDO NOT GLUEINSULATEDTRACER WIREFINISHED GRADESOIL PROFILE TEST PIT NO. 'ILEGENDsndyclay ¡oam0'l2J4567I104'DIASEWER LINEMEDIUM BROWN SANDY CLAY LOAMTO TANKHOUSENOTE: ORIGINAL SOIL REPORT (2007) BY HPGEOTECHUPDATED SOILS REPORT BY KUMAR ANDASSOCTATES (2021)/iCLEAN OUT DETAIL\9'--'-ñæ40END CAP MUST BEGLUED OR SECUREDIN A WATER TIGHTFASHION WITHUNDERGROUNDSEALANTENCASEMENT PIPE40 RIGID ENDNO GROUNDWATER OR BEDROCK ENCOUNTEREDDURING EXCAVATIONCAP AT EACH ENÞOF PIPEDIA SDR-35 SEWER LINE.HOLE DRILLED IN ENDCAP MUST ONLY BELARGE ENOUGH TOALLOW SEWER LINE TOFIT THROUGHMUST REST ON BOTTOMOF ENCASEMENT PIPE/ãENCASEMENT DETAIL\y NorrcruRuonavaara ResidenceTBD CR 31 1Gameld County, ColoradoProjectNumber: C1692DaIe: O2123n022Designed by: CBOReviewedDrawn by:by: RBDDw4.0Sheet 4 0F 4