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HomeMy WebLinkAboutOWTS Design Report 09.13.2018Huddleston-Berry Engineering & Testing, LLC RECEIVED sEP 2 0 2018 GARFIELD COUNîY G@ünmilMrlIìr !$Fv.Ettopflffili r 640 White Avenue Grand Junction, Colorado 81501 Phone: 970-255-8005 Fax: 970-255-6818 Info@huddlestonberry. com September 73,2018 Project#01 852-0001 Javier Orozco 336 Evergreen Drive Rifle, Colorado 81650 Subject: OWTS Design 3 Native Springs Drive Rifle, Colorado Reference Subsoil Study for Foundation Design and Percolation Testing, Proposed Residence, Lot 11, Native Springs,2T Native Springs Lane, Rifle, Colorado by H- P Kumar for Javier Orozco, August 6,2018. Dear Mr. Orozco, At your request, Huddleston-Berry Engineering & Testing, LLC completed design of an Onsite Wastewater Treatment System (OWTS) for a single-family residence at 3 Native Springs Drive in Garfield County, Colorado. The site location is shown on Figure I - Site Location Map. A site plan is included as Figure 2. Site Description As indicated in the referenced report, the site was vacant at the time of the subsoil study. The site was described as sloping down to the west at a grade of 5 to 10%. Site topography is shown on Figure 2. Yegetation consisted of grasses and weeds. In addition, an existing water well and active irrigation ditch were observed at the site. Subsurface nvestiøation As discussed in the referenced repoft, two profile pits and three percolation pits were excavated in the vicinity of the proposed absorption bed. The test pits encountered approximately 1.0 foot of topsoil above silty to clayey sand soils to the bottoms of the excavations. Groundwater was observed in the test pits at depths of between 7 .0 and 8.0 feet. The locations of the test pits are shown on Figure 2. Copies of the test pit logs are included in Appendix A. Onsite'Wastewater Treatment System As indicated in the referenced report, percolation testing was conducted in the percolation pits in accordance with Garfield County regulations. The percolation rate in the native soils ranged from 34 to 120 minutes-per-inch with an average of approximately 78 minutes-per-inch. The percolation testing data are included in Appendix B. 3 Native Springs 7@1#0r852-ooor (¿f;8,j)"!'i**":tLl,fi:,toe/13il8 \ø " In addition to the percolation rate of the subsurface materials, the seasonal high groundwater elevation is an important factor in determining the suitability of the site for Onsite 'Wastewater Treatment Systems. For OWTS suitability, the seasonal high groundwater elevation should be at least four feet below the bottom of the proposed absorption bed. As discussed previously, groundwater was encountered at depths of between 7.0 and 8.0 during the subsurface investigation. In general, based upon the time of year thaf the subsurface investigation was completed, HBET believes that the seasonal high groundwater elevation is deeper than 6.0 feet below the existing grade in the vicinity of the proposed absorption bed. Seepøge Bed Design The design of the absorption system generally follows the requirements of Garf,reld County as outlined in the Garfield County On-Site Wastewater Treatment System (O!4/TS) Regulations, effective June 30, 2014. The proposed construction at the site is anticipated to include a four bedroom home. Based upon the soil percolation rate, a Long Term Acceptance Rate (LTAR) of 0.20 will be utilized for the absorption field design. Infiltrator Systems Quick4 Standard Chambers are proposed in lieu of a conventional gravel absorption bed. The daily flow of the sewage disposal system is calculated below and a plan and profile of the absorption bed are shown on Figure 3. Average Daily FIow: (4 bedrooms)(2 persons/bedroom)(75 GPD/person) :600 GPD Soil Treatment Area : (600 GPD / 0.20):3,000 Square Feet Adjusted Soil Treatment Area : (3,000 SFXl.2X0.7):2,520 Square Feet # of Quick4 Chambers: (2,520 I 12):210 Chambers; Use 216 Chambers System Installation The installation of the septic tank, plumbing lines, Infiltrators, etc. should be completed in accordance with the Garfield County On-Site Wastewater Treatment System Regulations and Infrltrator Systems, Inc. specifications. In addition, the following construction procedures are recommended:. The septic tank and distribution box should be placed level over native soils that have been scarified to a depth of 8 to 12 inches, moisture conditioned, and recompacted to a minimum of 95Yo of the standard Proctor maximum dry density, within +2o/o of optimum moisture content. However, up to 3-inches of washed rock or pipe bedding passing the 1-inch sieve may be used as a leveling course under the septic tank and/or distribution box.. The bottoms of trenches and backfill around the septic tank and distribution box which will support sewer or effluent lines should be compacted to at least 90 percent of the standard Proctor maximum dry density, within +2%o of optimum moisture content. Pipe bedding should have a maximum particle size of l-inch.. Vehicular or heavy equipment traffic and placement of structures should not encroach within 10 feet of the septic tank or distribution box. 2X:U008 ALL PROJECTS\01 852 - Javier Orozco\Ol 852-0001 3 Native Springs\200 - Geo\o1 852-0001 LR09 l2l 8.doc 3 Native Springs #018s2-0001 09n3/t8 Hud¡llcston-Bcrry bdñshrÅ ¡i{bt. LrC Inspectìon Schedule Huddleston-Berry Engineering & Testing LLC should be retained to monitor the construction of the O'WTS. The following schedule of observation ancl/or testing shoulcl be followed:. Observe the absorption bed excavation prior to placement of Infiltrator chambers.. Observe placement of the septic tank, distribution box, and all connecting sewer and effluent lines prior to backfill. Veri$, proper fall between inverts. ' Observe and verify installation of the absorption bed prior to placement of cover and backfill. In conformance with Garfield County regulations, HBET will be required to provide Garfield County with documentation certifying that the OWTS was placed in conformance to the plan and profile and Garfield County regulations. General Notes The OWTS design was based upon the results of the subsurface investigation and on our local experience. The design is valid only for the proposed construction We are pleased to be of service to your project. Please contact us if you have any questions or comments regarding the contents of this report. Respectfully Submitted: Huddleston-Berry Engineering and Testing, LLC Michael A. Bemy, P.E. Vice President of Engineering JX:U008 ALL PROJECTS\o1 852 - Javier Orozco\o1 852-0001 3 Native Springsuoo - Geo\o1 852-0001 LR09l2l 8.doc FIGURES G Garfield Gounty Land Explorer GørJield County Garfield Gounty, Colorado 1ô.{, !¡¡üs q. /-ì +o I A"tú Å FIGURE 1 Site Location Map .+' 0.8 Mileso.2 0.4 1 inch = 1,505 feet 1 inch = 0.28 miles Garfield County Colorado ww,garf ¡eld-county, co m c¡lorådoGarfield County Garfield Gounty Land Explorer Printed by Web User Dlsclâimer Thls ls a comp¡latlon of rëcords as ffêy ¡ppê!r ln ùe cafléld øunq ofr.6s åffod¡nc th6 6rea shown, Thls dr.wlns ls b be usêd onlylor reteÈ ncå purp6os End th6 Gunty È nd ré5poñlble for ¡ny ln¡eur..¡es heEln.onbinêd. O copyright Garf¡eld county, colorado I A:l R¡ghts Reserved Printed: g/13/2o1s âL172124 PM?#Æ 3 NATIVE SPRINGS DR.FIGURE2-SITEPLANHuddleston-BerryEngincering & Tesl¡ng, LLCó40 whire Avenue, unit BGrand Junction, CO 8i501Project No.: 01 852-0001Date: 09/13/18By: MABDRAINAGE EASEMENTwdl6 '1t595GAL10,c)'LôU).cLo(no,ìzREPLACEMENT AREALot 11J Ndh SÞfrF Drh+.507MBLE PN IAIE¡Ss 89'34'41" W 4J6.74'Èpw JE2.29'stohpd 6 ¡eSS15' UTIL1TY AND IRRIGATIÍINCounty Road No. 221(ee b.)SCALE: 1":60'A rpsr Prr (APPRoxTMATE)RDruE PIIBomt'."C.I.:1FT DETAIL AREASCALE:1"=20'4.INCH DIAMETER SEWER ANDEFFLUENT PIPE MEETNG ASTMDI785, SCHEDULE 40 OR SDR 35INFILTfu\TOR SYSTEMS10,STANDARD CHAMBERSSEPT]C TANK WITHMINIMUMC-\LLON6', mNtxnDISTRIBUTIÔN BOXËS TIÍATENSURE EVÊNOF EFFLUENT**usE swEEP 90,s oRTWO 45'S AT 90DÊGR.EE tsENDS**3 NATIVE SPRINGS DR.FIGURE3-SEPTICSYSTEMDETAILSHuddleston-BerryEnginccring & Tcstïng, LLCó40 White Avenue, Unít BGrand Junction, CO 81501Project No.: 01852-0001Date:09/13/i8By: MABGEI{ERALIZED SYSTEM PROFILENof TuSCALERES]DENTIALSIRUCTURERISERS (AS NECESSARY)THAT LIDS ARE AT ORINFILTRATER OUICK4STANDARD CHAMBERSFINISHE¡ GRADE1,0 FT wN, cwRDN ETLUENTEST. 6.0TO A.O FTESTFT1,0 FT HIN.4,0ntg,30xEsTANKGENERALIZED BED PROFILEN¡T TBSCALETNFILTRATOR SYSTEMS QUICK4COVER SOILì NATTVE SOILS OR OTHER SUITABLETOPSOIL. CRADE TO CARRY SUR¡ACE WATERSTANDARI)BED.NEEDLE PUNCHED.FABzuC IMMEDIATELY ABOVE CHAMBERSMINIMUM SETBACKS(UNITS = F.T)rcPEgY LMt01010UNOryIE¡&uñryELUE1020LAXE, SIW,NNE! MCHÐI:l@ÐFrut0æ!0ffimcHbúúGATÐ HPE10ã10VAIER ÑE10át0tr10050**OTHER SETBACKS NOT LISTED HERE SHOULD BE IN ACCORDANCE WITH GARFiELD COLNTY OWTS REGULATIONS APPENDIX A Typed Test Pit Logs t: ¡; PIT 1 EL. 91' PIT 2 EL. 96 PROFILE PIT 1 EL. 95.5' PROFILE PIT 2 EL. 94.5' 0 0 WC=15,7 DD= 1 03 -200=67 -l ¡_l F tJJ UJl¡ ITÞ-fL t¡Jô WC= 1 5.7 DD= I 04 WC=19.0 DD= 1 02 ¡-.LIt¡lt& I :Et--o- Lrjô 5 5 10 10 LEGEND ñ TOPSOIL: SAN0. SILTY, ÇLAYEY, ORGANIC, STIFF' SLIGHTLY MOIST' BROWN' SAND (SC): CLAYEY TO VERY CLAYEY, SILTY, LOOSE, MOIST-WET, BROWN TO GRAYISH BROWN. F l-r+ HAND DRIVEN UNER SAMPLE. OISTURBED BULK SAMPLE. DEPTH TO WATER TEVEL AT THE TIME OF EXCAVATION. NOTËS. 1. THE EXPLORATORY PITS WERE EXCAVATED WITH A BACKHOE ON JULY 9,2018. 2. THE LOCATIONS OF THE EXPLORATORY PITS WERE MEASURED APPROXIMATELY BY PACING FROM FEATURES SHOWN ON THE SITE PLAN PROVIDED. 3. THE ELEVATIONS OF THE EXPLORATORY PITS WERE MEASURED BY HAND LEVEL AND REFER TO THE BENCHMARK ON FIG. 1 ' 4, THE EXPLORATORY PIT LOCATIONS AND ELËVATIONS SHOULD BE CONSIÐEREO ACCURATE ONLY TO THE DEGREË IMPLIED BY THE METHOD USED. 5. THE LINES BETWEEN MATERIALS SHOWN ON THE EXPLORATORY PIT LOGS REPRESENT ÏHE APPROXIMATE BOUNDARTES BETWEEN MATERIAL TYPES AND THE ]RANSITIONS MAY BE GRADUAL. 6. GROUNDWÀTER WAS ENCOUNTERÊD IN THE PITS AT THE TIME OF DIGGING. PITS WERE SACKFILLED SUBSEQUENT TO SAMPLING. 7. LABORATORY TEST RESULTS: WC = WATER CONTENT ('¿) (ASTM D 2216)¡ TD = DRY DENSITY (PCT) (ISTM D ?216)i -2QO = PERCENTAGE'PASSING NO. 200 SIEVE (ASTM D 1140). 18-7 *446 H-PryKUMAR LOGS OF EXPLORATORY PITS Fig, 2 APPET..{DIX B Percolation Testing Results H-PñI(UMAR TABLE 2 PERCOLATION TEST RËSULTS PROJECT NO. 18-7-446 Note: Percolation test holes were hand dug in the bottom of backhoe pits and percolation tests were conducted on July 9,2018. The average percolation rates were based on the last two readings of each test. HOLE NO.HOLE DEPTH (rNcHEs) LENGTH OF INTERVAL (MrN) WATER DEPTH AT START OF INTERVAL (rNcHES) WATER DEPTH AT END OF INTERVAL (rNcHEs) DROP IN WATER LEVEL (rNcHES) AVERAGE PERCOLATION RATE (MrN./rNCH) 1 EAST 31 15 7 6Vz Yz 80 6Y2 6r/a t/+ 6r/t 6 r/+ 6 53/¿rÁ 53/e 5%YB 5%5%r/t 2 SOUTH 3I 15 7%7V2 v, t20 7r/2 7V4 r/+ 7Y4 lYs Y" 7Vs 7 Ys 7 6%% 6%63/a r/s 3 WEST 33 15 7V4 6%% 34 6%6 % 6 5%% 5%5V4 % 5r/4 Ya % 4%4%r/z