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Home My WebLink AboutEngineer's Design Plan129 CAINS LANE CRneor.¡oRLE, CO 816,23 970.309.5259 ceRr¡. osre rRe.@euet t. co t'¡ RECE'VffiI} 'i | :'','liii..i .l: fl '.,,, ; "C,*5,[:,{Ë¡. u (.ì{:(¡r¡T \.u0Miìdl;i,J jI I f ;;-,1; i ,,;,ri, ,, , tt t.;l''l' I ( -" ( :( tñ'rtl Ir,'t. I ñ' (; November 27,2022 Project No. C1674 Chris Hjorth norskbuilders@qmail.com Subsurface lnvestigation and Onsíte Wastewater Treatment System Design G-Bedroom Main Residence + 2-Bedroom ADU Lot 23, Stirling Ranch Garfield County, Colorado Chris, CBO lnc. performed a subsurface investigation and completed an onsite wastewater treatment system (OWTS) design for the subject residence. The 8.168-acre property is located outside of Carbondale, in an area where OWTSs are necessary. Legal Description: Section: 29 Township: 7 Range: 87 Subdivision: STIRLING RANCH PUD Lot: 23 Parcel lD: 2391 -292-05-023 SITE CONDITIONS The property is currently undeveloped. A 6-bedroom Main Residence and 2-bedroom Accessory Dwelling Unit (ADU) are proposed. The residences will be served potable water from the community water system serving Stirling Ranch The water lines may not come within 1O-feet of the proposed septic tanks or within 2S-feet of the proposed soil treatment area (STA). The proposed soil treatment area (STA) location has an approximate 10 to 1 1 percent slope to the west The proposed area vegetated with sage and 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. SUBSURFACE The subsurface was investigated on October 24,2022 by digging two soil profile test pit excavation (Test Pit). A visual and tactile soil analysis was completed by Carla Ostberg.l A previous subsoil study and percolation testing was performed by HP-Kumar and results documented in a repoft dated December 1 1, 2017, Proled 17 -7 -7 B7 (enclosed). The materials encountered in Test Pit #1 consisted of dark brown clay loam topsoil to 1.S-feet, underlain by tan calcareous clay matrix explored to a maximum depth explored of 8.O-feet. No bedrock or groundwater was encountered. ' Carla Ostberg holds a Certificate of Attendance and Examination from the CPOWVisualand Tactile Evaluation of Soils Training. Page2 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 8.O-feet. No bedrock or groundwater was encountered. A sample of the soils was taken from Test Pit #1 at 3-feet below grade. Soil structure grade was moderate. The soilformed a ball and a ribbon approximately 1-inch in length before breaking. Soil structure shape was blocky and consistence was friable to firm. Soiltexture was both gritty and smooth. STA sizing is based on SoilType 2 with weak structure grade. A long term acceptance rate (LTAR) of 0.6 gallons per square foot. View of Test Pit #1 Test Pit #1 Backfill Page 3 Test Pit #2 DESIGN SPECIFICATIONS Desiqn Calculations: MainResidence=TSGPDx2people/bedroomx3Bedrooms+225GPD(4th,sthand6thBedrooms)=675 GPD ADU = 75 GPD x2 people/bedroom x 2 Bedrooms = 300 GPD Average Design Flow = 675 GPD + 300 GPD = 975 GPD LTAR = 0.6 GPD/SF 975 GPD / 0.6 GPD/SF x 0.8 (pressure dosed trenches) x 0.7 (chambers) = 910 SF The new OWTS design is based on 6-bedrooms in the Main Residence and 2-bedrooms in the ADU. An average daily wastewater flow of 975 GPD will be used. For the purposes of this OWTS design, Benchmark Elevation has been established as 100' as the Finished Floor (FF) of the Main Residence (Approx. 7075'). The ADU FF elevation appears to be at approximately 7081'. CBO lnc. should be notified of any discrepancies or problems with grade elevations of proposed components during installation of the OWTS. OWTS Gomponent Minimum Elevation Primary ïank lnlet lnvert ADU Tank Primary Tank lnlet Invert Main Residence ADU Tank to Pump Chamber Main Residence Tank to Pump Chamber (or tie into ADU sewer line) Approximate horizontal distance 29' I min.2o/o fall I min.7.25" fall Approximate horizontal distance 11' I min.2o/o fall I min. 2.75" fall Approximate horizontal distance 188' / min. 1o/o fall / min. 23.5" fall Approximate horizontal distance 14' I min. 1o/o fall I min. 1.75" fall Automatic Distributing Valve Approximate horizontal distance 57' I min. 1% rise for drain back / min. 7.125" rise lnfiltrative Surface Approximate horizontal distance to furthest trench 35' / min. 1o/o fall / min. 4.375" fall Page 4 *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 sewer lines exiting the ADU and Main Residence must be 4-inch diameter SDR-35 with double- sweep clean outs and a minimum 2o/o grade to the septic tank. There must be an additional clean out at least every 1OO-feet on the ADU sewer line. The system installation will include a 1OO0-gallon, two-compartment septic tank with an Orenco@ Biotube Effluent filter on the outlet to serve the ADU. An additional 2000-gallon, two-compartment septic tank with an Orenco Biotube Effluent filter must be installed to serve the Main Residence. A 5OO-gallon, single- compartment pump chamber must be installed with an Orenco@ Pump Vault and an Orenco@ PF3005 pump. Any state-approved poly or concrete septic tanks may be used, although we have provided preferred components as part of this design packet. The floats should be set to dose approximately 75 gallons each pump cycle, allowing approximately 6 gallons of drain back after each pump cycle. The control panel for the pump must be located within line of sight of the septic tank. We recommend Valley Precast out of Buena Vista be contracted for start-up of the pumping system. Table Effluent will be pumped through a 1.S-inch diameter pump line from the pump chamber to an Orenco@ automatic distributing valve (ADV), model6404. This pump line must have a minimum 1o/o 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 four gravelless chamber trenches, each 19 'Quick 4' Plus Standard lnfiltrator@ chambers, for a total of 76 chambers and 912 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.S-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 ellfacing up with a ball valve for ffushing. Valves may be placed in a valve box, accessible from grade, for access. lnspection 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. Dose Range Max = 249.75 gal. (975 GPD x 25o/o + 6 qal drain back) Min. 54 gal. (12 galx 4) + 6 gal drain back Dose Setting 75 gallons/dose 6 gallons drain back (57' I 1.5" diameter pump line) 500 gallon, single-compartment Valley Precast concrete pump chamber 7" onloff float separationFloat Separation Pump Criteria 17.8 gallons per minute (GPM)19.4 feet totaldynamic head fiDH) Page 5 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. ¡NSTALLATION 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 office is expected throughout the installation. INSTALLATION OBSERVATIONS CBO lnc. must view the OWTS during construction. ïhe OWïS 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 MANUFAGTURER MODEL NO.COMMENTS Septic Tanks lnfiltrator@ Valley Precast f nfiltrator@ Item # lM-1060 Item # 2000T-2CP Item # lMl-540-HH 1 000-gallon, 2-comp poly septic tank 2000-9allon, 2-comp :oncrete septic tank 500-gallon, single-comp ooly pump chamber with {H oumo Pump Orenco@ PF300511%HP 120 Volt Biotube ProPak Pump Packaqe Orenco(Ð BPP3ODD y'ault, Filter, Control Panel idemand dose) Tank Risers and Lids Orenco@ Double-walled PVC Risers and Lids (24" diameter) ADV OrencoG)V64U4A 1.5" lnlet and Outlets ADV Riser and Lid OrencoG)Double-walled PVC Risers and Lids (30" diameter) Orifice Shields Orenco(Ð OS150 1.5 inch diameter (8 total) Flush¡ng Assembly Orenco(Ð 1.5" diameter (2) 45" or 90" long sweep only (4 total) chambers lnfiltrator@ Plus Standard 76 'Quick 4' Chambers Page 6 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 propefi. 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. lf an effluent filter or screen has been installed in the OWTS, we recommend this filter 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 CONSTRUCTION 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 7 Pleaee call with quêst¡ons. Sinoerely, CIBO lnc. Garla Ostberg, MPH, REI-IS tw-be+elu'e Reviewed By: RomeoA. Baylosis, PE Pump Selection for a Pressurized System - Singte Famity Residence Project Norsk Builders I C1674 Parameters 300Discharge Assembly Size Transport Length Before Valve Transport P¡pe Class Transport L¡ne 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 Or¡fice Size Or¡fice Spacing Res¡dual Head Flow Meter 'Add-on' Friction Losses Calculations 't.25 57 40 1.50 6404 40 1.50 6 0 40 1.50 4 76 40 1.50 5132 3 5 None 0 inches feet inches feet inches feet feet inches feet inches inches feet feet inches feet o ü Io tt IEo .9 E(!g ê aú Ê 250 200 150 100 50 PumpData 0510 15 20 25 Net Discharge (gpm) 30 35 40 Minimum Flow Rate per Or¡fice Number of Orifices per Zone Total Flow Rate per Zone Number of Laterals per Zone o/o Flow Differential lsvLast Orifice Transport Veloc¡ty Before Valve Transport Velocity After Valve Frictional Head Losses 0.68 zo 17.8 1 4.9 2.8 2.4 gpm gpm o/o fps fps 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' Fr¡ction Losses Pipe Volumes 2.2 1.1 3.7 0.7 0_0 0.6 0.0 0.0 feet feet feet feet feet feet feet feet 0 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 6.0 3.7 0.0 8.0 6.0 11.7 gals gals gals gals gals gals PF3005 High Head Effluent Pump 30 GPM, ,I/2HP 1151230V 1Ø 60H2, 200V 3ø 60Hz PF3007 High Head Effluent Pump 30 GPM, 3/4HP 23OV 1Ø 6OHz,2OO|46OV 3Ø 60Hz PF30l0 High Head Effluent Pump 30 GPM, 1 HP 23OV 1ø 60H2, 200/460V 3ø 60Hz PF3015 H¡gh Head Effluent Pump 30 GPM. 1-1l2HP gpm feet \ System Curve: - Pump Curve:"" " HUmp ()ptrmal Kange: operating Po¡nt, G o Design Point: 23OV 1Ø 6OHz,2OOl230l460V 3Ø 60Hz N DRAWINGS MUST BE USED IN CONJUNCTION WITH DESIGN LETTER DATED 1 1 127 12022 SCÀLE: I = 50'=0" 1O.O'TYP, ESMT ?-4',VSEt ESMT. NITT / 23 P 6 ?//9 LIT 3,16 B t R/ST ¿ ACR AD t, c\ 'o 60 \.)/ESiP Irïll ,3t- I ( (o TOP ELE THE LOCATION OF PROPOSED IMPROVEMENTS SHOWN ARE NOT THE RESULT OF A PROPERry SURVEY, fHE LOCAÎIONS ARE APPROXIMATE. IT IS THE HOMEOWNERS'DUry TO ENSURE ALL CONSTRUCTION AND IMPROVEMENT LOCATIONS ARE ACCURATE. PROPERTY LINÊS ANÞ SETBACK DISTANCES SHOULD BE CONFIR¡,iED PRIOR TO EXCAVATION, SCALED FOR PRINTING ON 1'I" X 17' PAPER. k J \( Oo \.o C\\Êr() ADU SEPTIC TANK ô-BEDROOM RESIDENCE LINE Iul É, ¿f TP1 TP2 SEPTIC TANKS SCHOONER LANE VAULT J CBO lnc. 129 Ca¡ns Lane Carbondale, Colorado 81623 Phone 970.309.5259 carla.ostberg@gmail.com Norsk Builders, LTD Lot 23, Stirling Ranch Garfield county, colorado PrcjectNumber; C1674 Date:1112712022 Designed by: CBO Reviewed by: RB Drawn by: DD w1 .0 Sheet 'l 0F 4 N ? SCALE: 1 = 30'=0" OOO-GALLON, TWO-COMPARTMENT SEPTIC TANK WITH EFFLUENT SCREEN 3 tS U À 4'DIA SDR-35 SEWER LINE (1 % FALL TO PUMP CHAMBER) CLEAN OUT MIN. EVERY 1 4' DIA SDR-35 SEWER PIPE WITH CLEANOUT MIN 2% FALL TO TANK I 2OOO-GALLON 2-COIVIPARTMENT SËPTIC TANK WITH EFFLUENT SCREEN, RISERS AND LIDS TO GRADE. SINGLE.COMPARTMENT PUMP CHAMBER WTH ORENCO PUMPING SYSTEM. RISERS AND LIDS TO GRADE. ð 1.5' DIA SCH*40 PUMP LINE. (MIN 1% DRAIN BACK TO TANK) 1.5- DIA SCH-40 DISTRIBUTION LINES TO EACH TRENCH (MIN. 1olo FALL) /t rP1 + 4 TRENCHES EACH WITH 19'QUICK 4'CHAMBERS 76 CHAMBERS = 912 SF. 1.5" DIA SCH-40 PVC SUSPENDED LATERALS WITH 5/32'DIA ORIFICES 3' O.C- FACING UP. FIRST AND LAST ORIFICES FAC¡NG ÐOWN FOR DRAINAGE, COVERED WITH ORIFICE SHIELDS 4' DIA SDR-35 INSPECTION PORT AT BEGINNING AND END OF EACH TRENCH + TP2 PROPERTY LIN R E O CBO lnc. I 29 Ca¡ns Lane Carbondale, Colorado 8'l 623 Phone 970.309.5259 carla.ostberg@gmail.com Norsk Builders, LTD Lot 23, St¡rling Rênch Garfield County, Colorado ProjectNumberj C1674 Dale: 1'112712022 Designed by: CBO Reviewed by: RB Drawn by: DD w2.0 Sheet 2 0F 4 CBO lnc. 129 Ca¡ns Lane Carbondale, Colorâdo 81623 Phone 970.309.s2s9 carla.ostberg@9mail. com INFILTRATOR END PLATE \IUICK¿' CHAI,IBER (4'x 3')1,5' DtA SCH{o DISTRIBUTION LINE TÒ EACH TRENCH 1.5" DtA SDR-35 EFFLUENT PIPE FROM PUMP CHNBER DIASDR-35 SLIP.ON PVC ADV WIÎH ACCESS AT INSPÊCTION PORT DO NOT GLUE GRAOE INSULATED PUCED IN TOP POffi 4'ñax I L TRACÊR WIRE FINISHED GRADE OF CHAMBER END PLATES sotL _lLINE TO 4" DIA 4TH TRENCH (4 fot[)LIMIT SEWER L¡NE 4' DIA SDR.35 INSPECTION PORT A1 EEGINNING ANÞ ÊND OF ÊACH TRENCH EXCAVATION SUSPEND LATERALS WTH ZIP.TIES TO UNDERSIDE OF CHAMBERS GRAVELLESS'QUICK4' CHAMBER {4' x 3') SCARIFY SURFACE TO TANK END ÊACH LATERAL IN A 90" LONG SWÊÊPING ËLL FACING UP WITH A BALL VALVE IN A VALVE BOX ACCESSIBLE AT GRADË 1.5'DIA SCH"4O PVC SUSPENDED UTERAL wlH s/32" DrA ORtFICES AT 3'O.C. FACTNG UP. FIRST AND LAST ORIFICES FACE DOWN WTH AN ORIFICÊ SHIÊLD FOR DMINAGE. r;.\-C!¿i,EEE-IEEI.çH-SLCTON\:) /I CLEANOUT DETAIL L,l----j-ffi /ÀCHAMBER]RENCH PLAN\r,-ffiæ INSTALL FLUSHING VALVE ECCENTRIC TO CENTER OF VALVÉ BOX 10" DIA VALVE BOX W|TH SECURED LID SMALL VALVE COVER BOX OR ìRRIGATION VALVE BOX AT GMDE 30" DIAMEÏER PVC 1.5" PVC SLIP X MALE PIPÉ THREAD ADAPTERWCAP 1.5" DIA BALL VALVE RISER CAP ORTHREADED CLEANOUT ASSEMBLY 1.5'DtA SCH-40 PVC LONG SWEEP 90" ELBOW Trc COMPACT SOIL BASE fO SUPPORT BOX PVC PIPE CUITO FI.l- DISTRIBUTING VALVE ASSÊMBLY END CAP FROM USE HOLE SAW TO CUT THRU TOP OF PUMPING DIA SCH40 1.5'DIA SCH4O PVC SUSPENDED TATERAL END PVC INLET AND OUTLETS AINSPECTON PORT iN CHAMBERÉ/r-frræ /À AUTOMAÏC DISIRIBUTING\9r---"---'--"- ffiæ VALVE DÊTAIL /I FLL'SHING VALVE DETAIL\9¡-----rñæ Norsk Builders, LTD Lot 23, Stirling Ranch Gârfield County, Colorado ProjectNumber: C1674 llan,:11tz7t2o2z lDesigned by: CBO lReviewed by: RB lDrawn bv: DD w3.0 Sheet 3 0F 4 CBO lnc. 129 Cains Lane Carbondale, Colorado 81623 Phone 970.309.5259 €rla.ostberg@gma¡l.mm DESIGN 6.BEDROOM RESIDENCÊ + 2-BEDROOIV ADU 75 GPD X 2 PÊRSONS/BEDROOM X 3 BEDROOMS + 225 GPD (4th, sth ANd 6th BEDROOMS) = 575 75 GPD x 2 PERSONSßEDROOM x 2 BEDROOMS = 300 WASTEWATER FLOW = 975 GPD STA TO WATER COURSE 50'N/A STATO WELL 'f 00'N/A STA TO HOUSE 20'44 SEPTIC TANK TO WATER COURSE 50'N/A SEPIIC IANK TO WELL 50'N/A IVAIN HOUSE TO SEPTIC TANK 25' ADU TO SEPTIC TANK OWTS COMPONENTS AND PHYSICAL FEATURES MIN¡MUM REOUIRED SETBACK APPROXIMATE PROPOSED SETBACK TANK: MIN. I75O GALLONS TO SERVE MAIN RESIDENCE I\4IN. lOOO GALLONS TO SERVË ADU SOIL TRËATMENT AREA (STA): LONG TERM ACCEPTANCE RATE (LTAR) = 0.6 GAU SF CALCULATED STA = Q/LTAR = 975 / 0.6 = 1 625 SF PRESSURE DOSED, TRENCHES = 1625 SF X 0-8 = 1300 SF CHAMBERS = I 300 SF X 0.7 = 91 0 SF / 1 2 SF / CHAMBER = 76 CHAMBERS FOUR GRAVELLESS CHAMBER TRENCHES 19'QUICK 4'CHAMBERS IN EACH TRENCH TOTAL 76'QUICK 4' CI1AMBERS SOIL PROFILE TÊST PIT NO. 1 SOIL PROFILE TEST PIT NO. 2 LEGEND [= topso¡l l:rl ælca¡eous clay matrix 0 1 2 4 5 6 7 I 10 DARK BROWN TOPSOIL DARK BROWN TOPSOIL FINISHËÞ GRADE TAN CALCAREOUS CLAY MATRIX TAN CALCAREOUS CLAY MATRIX 24'MtN. 4'DIA SDR.35 SEWER (MlN 2% SLOPE TO TANK) SCREENED OR SAND FOR BEDDING 3" MtN. NO GROUNDWATER OR BËDROCK ENCOUNTERED DURING EXCAVATION 8" MtN. /:\.IRENCH DETAIL /ASOILS LOG\v BACKFILL Norsk Builders, LTD Lot 23, Stirling Ranch Garf¡eld County, Çolorado Project Number; C1674 Date:1112712022 Designed Reviewed Drawn by: by: CBO þy: RB DD w4.0 Sheet 4 0F 4 H-PryKUMAR Geotechnlcal Enginaering I EngineErlng Geology Materlals Testlng I Environmental 5020 County Road 154 Glenwood Springs, C0 81601 Phone: (970) 945.7988 Fax (970) 945-8454 Email: hpkglenwood@kumarusa.com Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, Summit County, Colorado December ll,20l7 ay Wright 630 East Hyman Avenuen Suite 101 Aspen, Colorado 8161I iav.wrisht @elliman.com projecr No.lT-7-287 Subject: Subsoil Study for Foundation Design and Percolation Testing, Proposed Residence, Lot23, Stirling Ranch, Skipper Drive and Schooner Lane, Missouri Heights, Garfield County, Colorado Dear As requested, H-PÆ(umar performed a subsoil study and percolation testing for foundation and septic disposal designs at the subject site. The study was conducted in accordance with our agreement for geotechnical engineering services to you dated October 20,2017. The data obtained and our recommendations based on the proposed construction and subsurface conditions encountered are presented in this report. Proposed Construction: This report was for the purchase/sale of the property in which the Clary's are the buyers. Design plans for the residence have not been developed. r#e assume that the proposed residence will be a one to two story wood frame structure over a basement or crawlspace and located on the site in the area of Pits I and2, shown on Figure 1. Ground floors will be slab-on-grade or structural over crawlspace. Cut depths are expected to range between about 2 to 7 feet. Foundation loadings for this type of construction are assumed to be relatively light and typical of the proposed type of construction. The septic disposal system is proposed to be located south of the residence in the area of the profile pits and percolation test holes shown on Figure 1. If building conditions or foundation loadings are significantly different from those described above, we should be notified to re-evaluate the recommendations presented in this report. Site Conditions: The lot was vacant and the topography appeared to be natural at the time of our field work. An existing fence line runs north to south through the eastern portion of the lot. There are pinon and juniper trees to the west of the fence and sage brush to the east. There is an -2- understory of grass and weeds across the lot. The lot slopes gently to moderately down to the southwest. Scattered basalt cobbles and boulders were observed on the ground surface. Subsidence Potential: The lot is underlain by Pennsylvania Age Eagle Valley Evaporite bedrock. The evaporite contains gypsum deposits. Dissolution of the gypsum under certain conditions can cause sinkholes to develop and can produce areas of localized subsidence. During previous work in the area, sinkholes were observed in the lower Roaring Fork Valley. Sinkholes were not observed in the immediate area of the subject lot. The pits were relatively shallow, for foundation design only. Based on our present knowledge of the site, it cannot be said for certain that sinkholes will not develop. In our opinion, the risk of ground subsidence at Lot23 throughout the service life of the residence is low and similar to other lots in the area but the owner should be aware of the potential for sinkhole development. Subsurface Conditions: The subsurface conditions at the site were evaluated by excavating two exploratory pits in the building area and two profile pits in the septic disposal area at the approximate locations shown on Figure 1. The logs of the pits are presented on Figure 2. The subsoils encountered, below about I ta Ir/z feet of topsoil, consist mainly of dense, basalt cobbles and boulders in a sandy clayey silt matrix. About lVzfeet of sandy silty clay with basalt rocks was encountered between the topsoil and mostly basalt rocks in Profile Pit 2 in the southern part of the septic area. Results of swell-consolidation testing performed on relatively undisturbed samples of sandy clayey silt matrix soils, presented on Figures 3 and 4, indicate low compressibility under existing moisture conditions and light loading and no to low collapse potential when wetted. The samples were moderately compressible under increased loading after wetting. Results of a gradation analysis performed on a sample of gravelly sandy loam (minus 3 inch fraction) obtained from the site are presented on Figure 5. The laboratory test results are summarized in Table 1. No free water was observed in the pits at the time of excavation and the soils were slightly moist. Foundation Recommendations: Development of a residence on the lot should be feasible from a geotechnical point of view. Considering the subsoil conditions encountered in the exploratory pits and the nature of the proposed construction, we recoûlmend spread footings placed on the undisturbed natural basalt rock soil designed for an allowable soil bearing pressure of 2,000 psf for support of the proposed residence. The matrix soils tend to compress after wetting and there could be some post-construction foundation settlement. Footings should be a minimum width of 16 inches for continuous walls and 2 feet for columns. I-oose and disturbed soils encountered at the foundation bearing level within the excavation should be removed and the footing bearing H-PVKUIVIAR Proiect No 17-7-7A7 -3- level extended down to the undisturbed natural soils. Exterior footings should be provided with adequate cover above their bearing elevations for frost protection. Placement of footings at least 36 inches below the exterior grade is typically used in this area. Continuous foundation walls should be reinforced top and bottom to span local anomalies such as by assuming an unsupported length of at least l0 feet. Foundation walls acting as retaining structures should be designed to resist a lateral earth pressure based on an equivalent fluid unit weight ofat least 50 pcffor the on-site soil as backfill excluding topsoil and rock larger than about 6 inches. Excavation below about 5 feet at this site will be difficult. Our experience in the Missouri Heights area is that a typical good-sized trackhoe excavator used for residential construction should be capable of excavating about 2 feet deeper in a foundation excavation than the depth where refusal to digging was encountered in our pits. Narrow excavations such as utility trenches and tight excavation corners may only be able to be excavated to the depth of our pits. Deeper excavations will likely require rock excavation techniques such as chipping or blasting. Floor Slabs: The natural on-site soils, exclusive of topsoil, are suitable to support lightly loaded slab-on-grade construction. To reduce the effects of some differential movement, floor slabs should be separated from all bearing walls and columns with expansion joints which allow unrestrained vertical movement. Floor slab control joints should be used to reduce damage due to shrinkage cracking. The requirements for joint spacing and slab reinforcement should be established by the designer based on experience and the intended slab use. A minimum 4 inch layer of free-draining gravel should be placed beneath basement level slabs to facilitate drainage. This material should consist of minus 2 inch aggregate with less than 5O7o passing the No. 4 sieve and less than ZVo passingthe No. 200 sieve. All fill materials for support of floor slabs should be compacted to at least 957o of maximum standard Proctor density at a moisture content near optimum. Required fill can consist of the on- site soils devoid of vegetation, topsoil and oversized rock. Underdrain System: Although free water was not encountered during our exploration, it has been our experience in the area that local perched groundwater can develop during times of heavy precipitation or seasonal runoff. Frozen ground during spring runoff can also create a perched condition. V[e recommend below-grade construction, such as retaining walls, crawlspace and basement areas, be protected from wetting and hydrostatic pressure buildup by an underdrain system. The drains should consist of drainpipe placed in the bottom of the wall backfill sunounded above the invert level with free-draining granular material. The drain should be placed at each level of H.PèKUMAR Project No.17-7-787 -4- excavation and at least I foot below lowest adjacent finish grade and sloped at a minimu m !c/o to a suitable gravity outlet. Free-draining granular material used in the underdrain system should contain less than 27o passingthe No. 200 sieve, less than 507o passing the No. 4 sieve and have a maximum size of 2 inches. The drain gravel backfill should be at least lr/zfeet deep. Surface Drainage: The following drainage precautions should be observed during construction and maintained at all times after the residence has been completed: 1) Inundation ofthe foundation excavations and underslab areas should be avoided during construction. 2) Exterior backfill should be adjusted to near optimum moisture and compacted to at least 95Vo of the maximum standard Proctor density in pavement and slab areas and to at least 9A7o of the maximum standard Proctor density in landscape areas. Free-draining wall backfill should be capped with about 2 feetof the on-site, finer graded soils to reduce surface water infiltration. 3) The ground surface surounding the exterior of the buitding should be sloped to drain away from the foundation in all directions. We recommend a minimum slope of 12 inches in the first l0 feet in unpaved areas and a minimum slope of 3 inches in the first 10 feet in pavement and walkway areas. A swale may be needed uphill to direct surface runoffaround the residence, 4) Roof downspouts and drains should discharge well beyond the limits of all backfill. Percolation Testing: Percolation tests l,vere conducted on November 13, Z0I7,to evaluate the feasibility of an infiltration septic disposal system at the site. Two profile pits and three percolation holes were dug at the locations shown on Figure 1. The test holes (nominal 12 inch diameter by 12 inch deep) were hand dug at the bottom of shallow backhoe pits and were soaked with water prior to testing. The soils exposed in the percolation holes are similar to those exposed in the Profile Pits shown on Figure 2 and consist of gravelly sandy loam to sandy loam. The percolation test results are presented in Table 2. Based on the subsurface conditions encountered and the percolation test results, the tested area should be suitable for a conventional infiltration septic disposal system. 'We recommend the infiltration area be oversized due to the variable percolation rate. A civil engineer should design the infiltration septic disposal system. Limitltions: This study has been conducted in accordance with generally accepted geotechnical engineering principles and practices in this area at this time. We make no warranty either expressed or implied. The conclusions and recommendations submitted in this report are based H-PryKUMAR Project Na.'17-7-787 -5- upon the data obtained from the exploratory pits excavated at the locations indicated on Figure l, the proposed type of construction and our experience in the area. Our services do not include determining the presence, prevention or possibility of mold or other biological contaminants (MOBC) developing in the future. If the client is concerned about MOBC, then aprofessional in this special field of practice should be consulted. Our findings include interpolation and extrapolation of the subsurface conditions identified at the exploratory pits and variations in the subsurface conditions may not become evident until excavation is performed. If conditions encountered during'construction appear different from those described in this report, we should be notified at once so re-evaluation of the recommendations may be made. This report has been prepared for the exclusive use by our client for design purposes. We are not responsible for technical interpretations by others of our information. As the project evolves, we should provide continued consultation and field services during construction to review and monitor the implementation of our recommendations, and to verify that the recommendations have been appropriately interpreted. Significant design changes may require additional analysis or modifications to the recommendations presented herein. We recommend on-site observation ofexcavations and foundation bearing strata and testing of structural fill by a representative of the geotechnical engineer. If you have any questions or if we may be of further assistance, please let us know. Respectfully Submitted, I.I.P*KUMAR Daniel E. Hardin, P Reviewed by: Steven L. Pawlak, P.E DEHlkac attachments Figure I - Location of Exploratory Pits Figure 2 - Logs of Exploratory Pits Figures 3 and 4 - Swell-Consolidation Test Results Figure 5 - USDA Gradation Test Results Table I - Summary of Laboratory Test Results Table 2 -Percolation Test Results H.PæKUMAR Project No,17-7-787 ı I È ! I o E LOCATION OF EXPLORATORY PITS , lE-f ¡ Ir¡ rI II ,I I 1 t Iir \ I I I f-î ----------a \P-2 A P¡T I \ I I ì I \ t\I 4 I 8 Lgr2í¡fi¡c-5:tñt Pn2 H-PVKUIVIAR F_J -:ï -\-" 6'\ I r I I ì( I I I ¡ãD o ¡r-aBÐtte " ?åä'hÐ A ¡:.5c-n .€D r tl- {ù kårâ¡¡ 1t¡ +*(l¡- -¡-h I I *I I ,f \ \ \ \ \\/ \ I \f o 120 APPROXIMATE SCALE-FEET 17 -7 -787 E ñ9 t 3 ı I I OZ PIT 1 PIT 2 PROFILE PIT 1 PROFILE PIT ? 0 WC=6.5 -200=76 LL=34 Pl= 14 0 F-f¡J l¿Ju- Irl-ô-t¡lo WC=7.4 GRAVEL=20 SAND=34 SILT=29 CLAY=17 -l i- L¡J l¡Jl¡ Irl-ô- t¡¡ô -¡ WC=11.4 DÐ=77 -2OO=7O WC=13.1 0D=74 -2O0=795 5 LEGEND TOPSO|L; oRGANlc SANDY OLAY AND slLT, wlTH GRAVEL AND COBBLES, FIRM, MotsT, DARK BROWN. BASALT COBBLES AND BOULDERS (GM): IN SANDY CLAYEY SILT MATRIX, DENSE, SLIGHTLY MOIST, WHITISH BROWN. CLAY (CL): SANDY, SILTY, WITH BASALT GRAVEL, VERY ST|FF, SL|GHTLY MOIST, BROWN. þ z-INCH DIAMETER HAND DRIVEN LINER SAMPLE. F I DISTURBED BULK SAMPLE PRACTICAL DIGGING REFUSAL. NOTES 2. 3. THE EXPLORATORY PITS WERE EXCAVATED WITH A BACKHOE ON NOVEMBER 13,2017. THE LOCATIONS OF THE EXPLORATORY PITS WERE MEASURED APPROXIMATELY BY PACING FROM FEATURES SHOWN ON THE SITE PLAN PROVIDED. THE ELEVAÏIONS OF THE EXPLORATORY PIÎS WERE NOT MEASURED AND THE LOGS OF THE EXPLORATORY PITS ARE PLOTTED TO DEPTH. 4. THE EXPLORATORY PIT LOCATIONS SHOULD BE CONSIDERED ACCURATE ONLY TO THE DEGREE IMPLIED BY THE METHOD USED. 5. THE LINES BETWEEN MATERIALS SHOWN ON THE EXPLORATORY PIT LOGS REPRESENT THE APPROXIMATE BOUNDARIES BETWEEN MATERIAL TYPES AND THE TRANSITIONS MAY BE GRADUAL. 6. GROUNDWATER WAS NOT ENCOUNTERED IN THE PITS AT lHE TIME OF DRILLING. PITS WERE BACKFILLED SUBSEQUENT TO SAMPLING. 7. LABORATORY ÎEST RESULTS: WC = WATER CONTENT (%) (ASTM D 2216)i DD = DRY DENSITY (pcf) (ASTM D 2216); -2OO = PERCENTAGE PASSING NO. 2OO SIEVE (ASTM D 11AO); LL = LIQUID LIMIT (ASTM D a318); PI = PLASTICITY INDEX (ASTM D 4318); GRAVEL = PERCENT RETAINED ON NO. 10 SIEVE SAND = PERCENT PASSING NO. 10 SIEVE AND RETATNED ON N0. JzS STEVE SILT = PERCENT PASSING NO. 325 SIEVE TO PARTICLE SIZE .002mm CLAY = PERCENT SMALLER THAN PARTICLE SIZE .002mm -.rL ,Z g 17 -7 -787 H-PVKUMAR LOGS OF TXPLORATORY PITS Fi1. 2 I E 3 È ã SAMPLI OFr Sondy Clcyey Silt Motrix FROM:Pitl@5' WG = I1.4 %, ÐÞ = 77 pcf -7OO = 7A % NÛ MOVEMENT UPON WTTTING ) riir6 tcr! rnitr{e qplty enry to th€ ¡qmÞl€: test.J, thê {êrliôq råAdd thall ñêì Þ6 fèÞroddr.d.6r€!Èt iô tull. *¡ü6u! th6 dìt¿ñ oÞp¡ovo! ot Kumor dnd Àtioc;¿lês, l¡c. 5r4ll Co¡solÌlalian lêrlinq prdoñld ;r ıc¿ordincr y;ih As'fil ¡-4516. ð:q JJtrl3ln I zg f-- ó:o tt1z0 0 *1 *2 -.? *4 *5 *6 t,0 APPLIËD PRESSURT *10 100 11 -7 *787 H-PryKUMAR SWTLL-CONSOLIDATION TEST RTSULTS Fig. 3 e Ê 4 SAMPLE OFr Sondy Clayey Silt Matrïx FfiOM:Pit2@3' WC = 13.1 %, DD = 74 pcf -28Q z 79 % I ADDITIONÂL COMFRESSION UNDTR CONSTANT PRTSSURI DUE TCI WTTTING \¡ Thô in 1 U J J [r¡ U) I zq t-- Õ J Õ an C){J _l *2 *3 *4 *5 *6 *7 I 1.0 APPLIED PRESSURË -10 100 17 -7 -787 H.PryKUMAR SWELL_CONSOLIDATION TTST RTSULTS Fig. 4 20t7 - lo@dñ Soösl am m =+3 o o oo o a @o No@o PERCENT RETAINED o oo oô{aao o i5 P b ¿¡ b 9o f 9r C]F m mf,t "Tì -o Ð-{ c)r zgrr nl m {J) o E a ñ o :D rnt- N)O \oo\ Ø zU C¡)Þ \oô\ cnI l\)(o \oo\ c) F J\¡ \oo\ c @U Øar --..1 .U !T 6) Â) (D: U) 0)fo. 5 0) 3 -n :go =3 J (g) J ¿tt t-N(¡ +i+++t-¿,4i-l--rilì li;illil;lij;rrl',,;l ffi iri,t:lrtlliliir!,ril,llrir, li iiliiiiiiiiili iiliiiiiiirl .t ljrli .ilrli \]i riilriiiriiiiil ; -+ \1ì ii :.i rl ìi -rj 'lti ti :.i j ll4 ì1ì 'i ilt¡ rl I ; I I I ll I ii'ì il/ L ililirl'l,r:irlll I l + rii ¿r ri t, aI oo{ô PERCENT PASSING a6oo ! I -J I \jæ\J -J. tT ¿¿ -^C n C ú LJÃ O -l Z --J FN U)-{nrrlaCr --J U) -¡ ç' H.P*KUMAR TABLE 1 SUMMARY OF LABORATORY TEST RESULTS Project No. l7-7-787 SOILWPE Sandy Clayey Silt Matrix Sandy Clayey Silt Matrix Gravelly Sandy Loam Sandy [.oam USDASOILTEXruRE CLAY (u') 1 7 (LL=34) (PI= 14) SILT (vù 29 SANX' (v") 7A 34 GFAVEL (vù 20 PERCENT PASSING NO.200 SIEVE 79 76 SAND (T"l GRAVEL (hl NATURAL DRY DENSITY (pcf) 77 74 NATURAL MOISTURE CONTENT e/.) 11.4 I 6J.I 'l.4 6.5 SAIIPLE LOCATION DEPTH (fr) -J J 1r/*2Vz Wz-ZVz PIT I 2 Profile Pir 1 Profi.le Pit2 H:P*KUMAR TABLE 2 PERCOLATION TEST RESULTS PROJECT NO. 17-7-787 Note: Percolation test holes were hand dug in the bottom of backhoe pits. percolation tests were conducted on November 13,2017. The average percolation rates were based on the lasttwo readings of each test. HOLE NO.HOLE DEPTH (rNcHES) LENGTH OF INTERVAL (MrN) WATER DEPTH AT START OF INTERVAL (rNcHES) WATER DEPTH AT ENO OF INTERVAL (rNcHES) DROP IN WATER LEVEL (rNcHES) AVERAGE PERCOLATION RATE (MrN.fiNCH) P-1 26 30 7 5Y4 13/o 60 514 4/t 1 4Y4 3Y1 1 g1/4 2%Y. zsL 2%Y. P-2 25 30 g%I 13/e 40 I 7Yl % 7lh 61A 1 61/¿íYz % 51h 4r/t '/+ P-3 28 30 81/,7%Y. 34 7%6 1s/c 6 4%1% 4Y¿4 % 4 3 1 ÇqPublb.net* Garfield County, Co Account Number Parcel Number Acres Land SqFt Tax Area 2019 Mill Levy R008798 Physical Address 239729205023 I Owner Address 0 011 79.7760 OSKIPPER DR CARBONDALE NORSK BUILDERS LTD 79 NAVAJO CARBONDALECO 81623 2019Total Actual Value Overview Legend f-l Parcels ' Roads Parcel/Account Numbers Owner Name f',rî Lakes&Rivers - CountyBoundary Line $250,000 Last2Sales Date Price 7O/2I/2O2O $2o5,ooo t2/t/2o77 $O 81623 Date created: LO/ 23/2022 Last Data Uploaded: IO/I3/2A22 !2:05:75 AM Deveroned bv(Ét) FFtrBFlRt 10123122,3:43PM Summåry Account Percêl ROO8798 239129205023 OSKIPPERDR,CARBONDALECO S1ó23 qPublic.nêt - Garfisld County, CO - Propêrty Record Card: R008798 GÐqPrlHisneü" Garfield County, CO Þrcperty Address Leg¡l S€ctlon:29 Townshlpr 7 Range:87 suM¡vlslon: STIRLING RANCH PUD Lot:23 EXCEPT A TR oF IAND ftesrlptlon CONT.035ACASDESC lN ÊOUNÞARYLINEADJ REC#6óó9óó.8.1óSACRES Acr6 4.1ó8 LendsqFt 0 l¡xArea 11 Mtlltwy 79J76O Slbd¡Y¡slon SIIRLINGRANCHPUD Vlil Map ùvner NOR5K BUITDERS LTD T9NAVAJO CARBONDALE CO81ó23 Land Unlt lyp6 VACANT RES LOTS - 0100 (VACANT LAND) SquareFeêt 0 Actual Values $23s,000.00 Ai:qs9qY9¿r L¿nd Actuâl 2022 srio,ooo.oo ._ $2!p,ooooo 2027 ?020 fotal Actual Assess€d Valu€s A!s6*d Ydr Tax Hl¡tory TåxY-eI .. Texs B¡lled lmproveme¡t Asseßsed Tot¡lAsssd $2s0,000.00 2t22 $0.00 $250,000.00 $0.00 $23s,(x)O.00 2024 $72,500-00 {0.0o $72,500.00 ?o?l $s,783.7ó . ?o.2-o 55.747.92 2U¿1 arr,ioü.bô $q8,lio:w $ooo $68,150.00 $0.0o $7¿5m.(x, 2û79 $s,rs¡.¿a ?918 94767-04 1t3 1Of23122,3:43PM Cl¡ck here to view the tax lnformatlon for thls oarcêl on the Gârtl€ld Corntv Tressurer's website. Trânsfers qPublic.nêt ' Garfield County, CO - Properly Record Card: R00ô798 R9.."p-t-19!N![!ul .. . ..-w.sê Bøk- Peæ Sale Prlê \au2ø!7 7UU2017 _wARl¡!:rrYqFFD.. . . .alJllclAlM DE€q. STATEMENT OF AUTHORITY.!up!?9.17 72./3t20L3 uì¡invü'.allLl.c!¡!M 9qE--D- QUIT CLAIM OEED rysc 9d)729 8439ó8 .lÉ-w.Þ-z 705103 Éq!94 . .4q5.9199 7354-672 QUITCLAIM DEED . ?E9!ôRAM|' AGRËËMENI $g $o $9. $0 711.1t?W ,5lt-4/?q? .. .. . 5192w2 .u!stlw-?. 711512ú2 qryç!ôlw¡¡l4llTYDEFP . .W4\RANTVDEFP-. . PERSONAL REPDEED . É999æ ¡¡Ég¡g 99,49!¡ !ll1-óÉ.,2 . 7r22J92. 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