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Home My WebLink AboutSubsurface Investigation for OWTS Design 09.29.2014AL • 3 Four Wheel Drive Rd Carbondale, CO 81623 910·309-5259 ~rn~mf ~ . I H September 29, 2014 Christopher Fallen and Katherine Rosen Christopher.fo llen@gmail.com Subsurface Investigation and Onsite Wastewater Treatment System Design TBD Glenwood Avenue Garfield County, Colorado Chris and Katherine, Project No. C1099 ALL SERVICE septic, LLC performed a subsurface investigation and completed an onsite wastewater treatment system (OWTS) design for the subject residence. The property is located in Satank, outside of Carbondale , in an area where OWTSs are necessary. SITE CONDITIONS The 1.149-acre property is currently undeveloped, with the exception of a shed which will be demolished. Native vegetation and grasses exist on the property. There is slight slope to the north , toward the Roaring Fork River, on the south portion of the property. The northern portion of the property drops steeply toward the river. A single-family residence is proposed, with a maximum future build-out of 4- bedrooms . The residence will be served by a public water system. A ditch runs to along the west property boundary. This ditch will be lined or placed in a culvert within 50- feet of the proposed soil treatment area (STA). A private well is located on the neighboring property to the east. A minimum 100-foot setback will be maintained from this well to the proposed STA. SUBSURFACE The subsurface was investigated on September 19, 2014 by digging two 8-foot soil profile test pit excavations (Test Pits) and conducting a visual and tactile evaluation of the soils. The materials encountered in the Test Pit #1 consisted of dark brown, moist, topsoil to 1-foot, underlain by dark brown, moist, sandy, silty, loam with a granular shape, moderate structure grade , and firm consistence to 3-feet, underlain by dark brown to gray sandy, silty, loam with cobbles 2 to 6-inches in diameter to a maximum depth explored of 7-feet. No bedrock or groundwater was encountered . The materials encountered in Test Pit #2 consisted of medium brown, moist, topsoil to 1-foot, underlain by medium brown, moist, sandy, silty, loam with a granular shape, moderate structure grade , and firm consistence with 2 to 4-inch diameter cobbles to 4-feet, underlain by similar material with larger cobbles , appro ximately 4-inches to 1-foot in diameter to a maximum depth explored of 8-feet. No bedrock or groundwater was encountered . A long term acceptance rate (L TAR) of 0.8 gallons per square foot, will be used to design the OWTS, in accordance with Table 10-1 Soil Type 1 presented in the Garfield County On-Site Wastewater Treatment System Regulations, adopted April 14, 2014. Test Pit #1 T est Pit #2 This horizo n wi ll be utili zed as th e infiltrative area T es t Pit #2 ro ckier at shallower depth from native grade. DESIGN SPECIFICATIONS De sign Calcul ati ons: 75 GPO x 3 bedrooms x 2 people = 450 GPO 75 GPO x 1 bedroom x 1 person = 75 GPO 450 + 75 = average daily wastewater flow 525 GPO T ank Capacity: 4 bedrooms requires 125 0 gall ons Additional 250 ga ll ons to accommodate pump = 1500 gallons Soil Treatment Area (STA): 525 GPO I 0 .8 ga ll ons/ SQ FT = 656 SQ FT 656 SQ FT x 1.0 press ure dosed bed = 656 SQ FT 656 SQ FT x 0 .7 chamb e rs= 459 SQ FT Minimum 38 'Qui ck 4' Infiltrator® chambe r s Page 2 Th e OWTS design is ba sed on 4-bedrooms. An ave r age daily wastewater flow of 525 GPO will be use d. Th e syste m in sta ll atio n will include a new 1500-gallon, two-compartment concrete septi c t ank with an Orenco® Biotube Pump Vault and Orenco® PF 3005 pump in stalled in the second co mpartment of the Page 3 septic tank. On/Off floats should be spaced approximately 10-inches apart to achieve a 100-gallon dose. The control panel for the pump should be located within line of sight of the septic tank. Effluent will be pressure dosed through a 1.25-inch diameter pipe to an Orenco® model 4402 automatic distributing valve (ADV), and then to two gravelless chamber beds, each with three rows of seven 'Quick 4' Infiltrator® chambers, for a total of 42 chambers and 504 square feet of infiltrative area. The chambers in each bed will be connected by a 1.25-inch diameter level manifold. Laterals will be hung with zip ties from the underside of the chambers, with 3/16-inch diameter holes facing up, with the exception of the last hole facing down for drainage. The holes must be placed 2-feet on center. Each lateral must end in a 90 degree elbow facing up with a ball valve for flushing. These may be placed in a valve box, accessible from grade, for access. Topsoil and vegetation will be over-excavated from the bed area and the chambers placed approximately 1-foot below native grade. The infiltrative area will be in the sandy loam/ loamy sand horizon approximately 2-feet above the more gravelly horizon. There must be at least 1-foot of fill over the top of the chambers, which will cause the field to be slightly mounded. Slope of the mounded portion must be a minimum 3:1 slope. The component manufacturers are typical of applications used by contractors and engineers in this area. Alternatives may be considered or recommended by contacting our office. Construction must be according to Garfield County On-Site Wastewater Treatment System Regulations, the OWTS Permit provided by Gartield County Building Department, and this design. REVEGETATION REQUIREMENTS An adequate layer of good quality topsoil capable of supporting revegetation shall be placed over the entire disturbed are 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 irritation shall be plated 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 absorption area. No heavy equipment, machinery, or materials should be placed on backfilled STAs. 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. The homeowner should pump the septic tank every two years, or as needed gauged by measurement of solids in the tank. Garbage disposal use should be minimized, and non-biodegradable materials should not be placed into the OWTS. Grease should not be placed in household drains. Loading from a water softener should not be discharged into the OWTS. No hazardous wastes should be directed into the OWTS. Mechanical room drains should not discharge into the OWTS. The OWTS is engineered for domestic waste only. Page 4 ADDITIONAL CONSTRUCTION NOTES If design includes a pump , air release valves and weep holes must be installed to allow pump lines to drain to minimize risk of freezing . The pump shall be connected to a control breaker separate from the high water alarm breaker and from any other control system circuits . Excavation equipment must not drive in 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 . INSTALLATION OBSERVATIONS ALL SERVICE septic, LLC 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 . ALL SERVICE septic, LLC should be notified 48 hours in advance to observe the installation. LIMITS: The design is based on information submitted. If soil conditions encountered are different from conditions described in report, ALL SERVICE septic, LLC 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 . Pl ease call with questions. Sincerely, ALL SERVICE septic, LLC Revi ewed By: ~~.~ ' Rich ard H. Petz, Carla Ostberg, MPH, REHS Liability Clause: Under no circumstances whats oever shall th e liability of ALL SERVICE septic, LLC, in conn ection with any contract, directly or indirectly, excee d th e total amount p aid by th e client to ALL SERVICE septic, LL C for the services and/or goods which are th e subject of th e contra ct in connection with which the liability arises. Pump Selection for a Pre s surized System -Singl e Fa mi ly Residenc e Pr oj e ct Pa ra mete rs Discharge Assembly Size 1.25 indles Transport Length Before Valve 20 feet Transpo rt Pipe Class 40 Transport Line Size 1.2 5 i ndles Distributing Va Ive Mode 4402 Transport Length After Va l ve 10 fe et Transport Pipe Class 40 Transport Pipe Size 1.25 i n dles Max El evation Li ft 3 feet Ma ni fold L eng th 6 feet Manifol d P ipe Cl ass 40 Mani fold Pipe Size 1.25 indles Number of La terals per Cell 2 ..... Lateral Length 19 fe el 1> Cl Latera l P ipe Class 4 0 !!:. L ateral P ipe Size 1.25 indles :c Ori fice S i ze 3/16 i n dies ~ Ori fi ce S p acing 2 feet -0 Residual H ead 4 feet i Fl ow Meler None indles !!l 'Add-on' Fricti on Losses 0 feet E Calcul ation s 2 ~ M ini mum Flow Rate pe r Orifice 0.87 gp m i Number o f Ori fi ces per Zone 10 {l Total Fl ow Rate per Zone 8 .7 gpm Number o f Lateral s per Zone 1 % Flow Differential 1st/L ast Ori fi ce 0.8 % Tra n sport Veloci ty Before Valve 1.9 fps Transport Ve l ocity After Valve 1.9 fps Fri ctional Hea d Losses Loss through Discharge 0.5 fee t Loss in Transport Before Va l ve 0 .2 feet Loss thro u gh Val ve 1.9 fee t Loss i n Tra n sport after Valve 0.1 feet Loss in Mani fold 0 .0 fee t Loss in Latera l s 0 .1 fee t Loss thro u gh Flo wmeter 0.0 feel 'A dd-on' Fri ction Losses 0 .0 feel Pi[!e Volum es Vol of Tra n sport Line Before Val ve 1.6 gal s Vol of Tra n sport Line After Valve 0.8 gals V ol of Mani fold 0 .5 gal s Vol of Lateral s per Zon e 1.5 ga l s To tal Vol Before Val ve 1.6 g als Total Vol A fter Va l ve 2.7 gals Min im um PumE! Regu i rements Design Flow Rate 8.7 gpm Tot al Dyna mic Head 9.9 feet ~ ~ ca 0.-.IKO 8rw l.olm 1' 1Wj)l"1'>11'JO ,~ .. ~"" I 1~ ..... ~ t:~ hti , I I u I t I..!-I ,_ I '· -.LL _.._ ,_ -4-1-... ·+-1-•-1-•-··---I JI I ,_ ---r. ·--.,..-1-. ,_ 1. ,_ -;.- I -.. 1+ I ,_ T ··-. 1---I ·--r -.... I I I I ' ' ' I I I ,_ T ,_ ·-....._ J ,_ __._. 1-1-•-r-,_,_ ·--r- .. "7.·11 I I\ ·-I+ -+ l ·-~ r-r ,_ ·f ,_ -~t r~ _,_ 1-.--tt ,_ •-I+ ,_,_ ,_,_ ,_,_ ,_ ,_ ·-·. I I t [\• I ! I I --·---.. I .... rY'~»i 1 ,_1_ '-'-[\-I L ,_ --,_ f-,_.._,_ I - -...... _ ' -,_ '-'--, _ _,_ ..... , ,_ ...... ,J \ +-1-........ ,_ .... _,_,_ ,_ \ r' \I · ,_ 1. f •· -... \ " ' \ -~ " " '\. l-l ~ I\ _,_ ...... ,_ ~ r\ -'-r'\ ·-t\ ,_ .r .. •->- :r!J ~) t'\ ' ,_ ,_ \ r\ ' '·, \ ,_,_ .... ,_ -·-'-'-r .... r-.. I\ ' ,_ - ~- ' ' ~~ ,~t:I-: . ' . -~ , ... t>.. li \ ·~"" 1 .. )'-~ \ .... -•. ~ ..... ~. '\ \ \ -. ,_ i-..1,, ~~ -_,_ -.... " ~>-- ~ 1, \ ~ r• "' ,...l--' ~ \\[\ i... ., ..,.i.... ' ~ ..... _,,_ ' r-. \t\ ....... . .,,r--. 300 25 0 200 15 0 100 50 ....... .,, -, i....i... ,_,_ .., 5 10 15 20 25 30 35 4 0 Net Di sc h arge (gpm) Pum[!Data PF3005 Hi gh Head Efflu ent Pump 30 GPM , 1/2 HP 115/23JV 10 6 CJ-t z,2 0CW 3060Hz PF3007 Hi gh Head Efflu ent P ump 30 GPM , 3/4 HP 230V 10 60Hz, 200/460V 30 60Hz PF30 10 Hi gh Head Efflu ent P ump 30 GPM, 1HP 230V 10 60Hz, 200/460V 30 60Hz PF3015 High Head Efflue nt P ump 30 GPM, 1-1/2HP 230V 10 60 Hz, 200/230/460V 30 60Hz L egen d System C u rve: - Pump Curve : - Pump Opti mal Ran ge ,_ Operating PointQ Design PointQ