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Home My WebLink AboutOWTS Installation Observations 04.25.18ESGM www.sgm-lnc.com April25, 2018 Mr. Jim Wilson, Building Official Garfield Cou nty Building Depa rtment 108 8th Street Glenwood Springs, CO 81601 RE:Smith OWTS 2995 CR 311, New Castle, CO OWTS Design Dear Jim, This letter is intended to follow up an onsite investigation of the onsite waste treatment system that we provided a design for last fall. Our inspection was intended to ascertain that the OWTS was constructed perourdesign of 9/29/77 coupledwiththefollowupletterof October25,2OI7. Tothatend,wehave confirmed that the inspection was in fact installed accordingly. Upon your receipt and review, call with questionsl Respectfully, Prin GLENWOODSPRINGS llSWestSixthSt,Suite200 lGlenwoodSprings,COSl601 1970.945.10O4 ESGM www.sg m- ln c. c o m October 25,2OL7 Mr. Jim Wilson, Building Official Garfield County Building Department 108 8th Street Glenwood Springs, CO 81601 RE:Smith OWTS 2995 CR 311, New Castle, CO OWTS Design Dear Jim, This letter is intended to follow up our prior letter of 9129/L7 which provided a design of the OWTS for the Smith Family down on Divide Creek next to CR 311. ln that design, we had referenced the installation of an Orenco AX20 series treatment unit to achieve TL3 for setback reasons. This treatment unit was proposed to sit atop a 1,500 gallon sept¡c tank. After working with the manufacturer and supplier, it has been determined that an acceptable alternative to the AX20 unit is the installation of a minimum 1,000 gallon concrete sept¡c tank followed by the installation of a AX20 RT unit in a 800 gallon recirculation tank. Also, in order to provide a compatible pump for this unit and minimize substantial electrical needs, we are recommending that the distribution piping within the infiltrator trenches be drilled with 1/8" diameter holes at 48" o.c. for perforations in lieu of the/n" diameter holes at 30" o.c. Call with questions! llv, Simonson, PE, CFM Prin GLËNWOOD SPRINGS I l8 West Sixth St, Suite 200 | Glenwood Springs, CO 81601 | 970.945.14O4 SSGM www.sgm-rnc.com September 29,2077 Mr. Jim Wilson, Building Official Garfield County Building Department 108 8th Street Glenwood Springs, CO 81601 RE:Smith OWTS 2995 CR 311, New Castle, Colorado OWTS Design Dear Jim, The purpose of this letter is to transmit the design regarding the onsite waste water treatment system (OWTS) for Shane and Sarah Smith located at 2995 CR 311, New Castle, Colorado, Assessor parcel number 2t79734O0018. The specific location of the property in question is located in Figure 1. F¡gure 1- Vicinity Map Accounl R083é99 Owner SMlTH, IJLEERT SHANE & SARAH K Phyricol Address Nol ovqilsble slLT Blð52 Moiling Addree¡ 4CI23 HIGHWAY l0S |DAHO SPRINGS. CO 8û452 Acres 35.257 2Ð16 Mill levy 50.4480 3 {9 gffi ftN 217?r3400018 ffi nepo:l Eoetcils x S Tox H gle¡ Elemoil GLENWOOD SPRINGS I l8 West Sixth St, Suite 200 | Glenwood Springs, CO Bl60l | 970.945.1004 ESGM www.sgm-lnc.com This onsite wastewater treatment system is intended to serve an new three bedroom house. As you will see on the schematic drawings and information attached, the home will be provided with a gravity service from the home to a minimum sized 1,500 gallon AdvanTex Treatment System that can be set on either the standard poly tank (manufacturer provided) or a precast concrete sept¡c tank. From the AdvanTex Treatment System, the effluent supernatant will be transported to a proposed pressure dosed lnfiltrator Quick4 trench disposal system. Each of the four proposed trenches is to be 72 feet long with 18 euick4 lnfiltrators to comprise the system. Standard end caps are proposed on the end of each trench. The piping from the AdvanTex System to the trenches shall be a minimum diameter of 1" class 160 pvc and shall be looped from front to back (including the perforated class 160 pvc pipes inside the infiltrators). Locations of the new tank and infiltrator trenches will be specified ¡n the attached drawing plan of this package in an area located just north and east of the building honoring property line, building, ditch, floodplain and Divide Creek ordinary high water setbacks' Given the use of the AdvanTex Treatment units, the treatment level for the system is that of a TL3 with CBOD to be dropped to 10 mg/|, TSS to be dropped to 10mg/l and Total Nitrogen being dropped to a 40- 60 mg/l level as is identified in Table 6-3. Because of the use of the TL3, infiltrator trenches and pressure dosing, the setback from the creek to the infiltrator trenches needs to be 25 feet. As well, the setback from the irrigation ditch can be 25 feet. The separation from the bottom of the infiltrators and the ground water can be 24" (2 feet). During soils testing, ground water present in the soil profile hole at a depth of 5 feet. The overburden soils were consistent and appeared to be a loamy material consistent with soil type 4 identified in Garfield County OWTS Regulations Table L0-1. Research was performed to gain insight on the specific soils parameter utilizing the SCS WebSoil survey. The percolation rate determined for design is greater than 60 minutes per inch which appears to be consistent with the Arvada Loam identified in the SCS Websoil Survey. The exhibits attached to this letter identify the information that was researched in addition to the testing performed to help determine the LTAR (Long Term Acceptance Rate) for the STA (Soil Treatment Area) for the design of the new disposalfield. Exhibits are listed as follows t. Exhibit A: 2. Exhibit B: 3. Exhibit C: NRCS Physical Properties RePort N RCS Engineering Propert¡es Report Websoil Description of Soils GLINWOOD SPRINGS I lB West Sixth St, Suite 200 | Glenwood Springs, CO Bl601 | 97A.945.1OO4 gSGM www.sgm-lnc.com Based researched data, the LTAR for the on-site soils is 0.30 gallons per day per square foot. With this data, the STA (Soil Treatment Area) is 1,500 square feet. Because we will incorporate the use of lnfiltrators (chambers) and pressure dosing we have employed the size adjustment factors and reduced the trench size by the following: For using chambers, a 0.7 factor is applied. For using pressure dosing, the 0.8 factor is also applied, thus resulting is an area of 840 sf. This results in four infiltrator Quick4 chamber trenches of dimension 72' inlength. Theattachedcalculationsidentifythethoughtprocessinthedesignofthissystem. The design and layout of the system is shown on the attached drawing following this letter Upon your receipt and review, if you have any questions, please don't hesitate to call. Respectfully, SGM-I son,PE,FM Princ ä81 52 9t29t17 GLËNWOOD SPRINGS I lB West Sixth Si, Suile 200 | Glenwood Springs, CO Bl60l | 970.945.10O4 OWTS Design Report and Calculations Client:Smith OWTS 2995 CR 311 New Castle, Colorado 81547 Date: 29-Sep-17 Flow Dãta for the OWTS Design 1 Home Use (3 Bedroom Home) Home Use 4s0 gpd 4s0 gpdTotals: 2 Septic Tank Sizing 3 Flow calculated from above: 450 gpd 48 hour detention time for sept¡c tank sizing; 450 450Total= For Home Use, 2 persons per bedroom and 75 gallons per day per person, BOD5 = 0.06 #/person/day 0.48 #/day O.48 #lday Soll Data for the OWTS Data from on-site soil observations: Appears to be a loamy soil of consistent depth from surface to a depth of 5 feet where gravely clays and ground water are encountered Däta from the web soil survey indicates a Arvada Loarî ex¡sts. Percolation Rate: > 60 mpi Given the consideration of all data, the Long Term Acceptance Rate to use is 0.3 Sallons/sf/day Volume=900 cpd 1000 gallon tank required at a minimum Sizing of Absorption Field or Soil Treatment Area 5 Going with a soil type 4 and Treatment Level 3, LTAR =03 s/srld For a pressure dosed system, size adjustment factor is 1.0 for a bed configuration For a grav¡ty system, the s¡ze adjustment factor shall be 1.2 for a bed configuration For a gravity trench system, adjustment factor = 1.0 For a pressure dosed trench system, adjustment factor = 0.8 For use of chambers: size adustment factor is 0.7 STA= Flow/LTAR 1500 square feet (unfactored) For a chamber system, pressure dosed, adjust size to 0.7*1500*.8=840 square feet For a chamber system in a trench configuration, length= 280 feet Number oftrenches: 4 (this would equate to 4 runs of 70 ft each) (equals) With the effective length of a Quick4 chamber at 4', use 18 chambers per trench Thus the net length ofthe runs will be 72'each. 18 infiltrator units pertre OWTS Design ond DetoilsGorfield CounlySmith ReidenæSSGMI ì8 Wêt Sixlh Steer, Sqilê 200Gleñúood Spi.ss, CO 8ló01970.945.1æ4 www.sñ.in<..ôñINFILTRATOR SYSTEMS INC.QUICK4 STANDARD CHAMBERAf ENDS Of Nf fBilCHPfuW SIANMD END48'aPs ù Nnlnam ,nn t' u. uat ætttto\fu END M ANACH I. 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