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Home My WebLink AboutEngineer's OWTS Design PlanHuddleston-Berry Engineering & Testing, LLC M:ay 12,2025 Project#02205-0002 Casey Sheets 59 County Road 317 Rifle, Colorado 81650 Subject OWTS Design - Parcel 217927101002 ADU Silt, Colorado Dear Mr. Sheets, At your request, Huddleston-Berry Engineering & Testing, LLC completed design of an Onsite Wastewater Treatment System (OWTS) for an Accessory Dwelling Unit (ADU) at Parcel 217927101002 in Silt, Colorado. The site location is shown on Figure I - Site Location Map, A site plan is included as Figure 2. Site Description At the time of the investigation, an existing residence and a shop occupied the northern portion of the site. The remainder of the site was open and sloped down to the southwest. Site topography is shown on Figure 2. Vegetation consisted of weeds, grasses, and small to large bushes. The site was bordered to the north, west, and east by open land, and to the south by Alta Mesa Road. Subsurface Investigation In order to evaluate the subsur ce conditions at the site, three test pits were excavated at the site. The locations of the test pits are shown on Figure 2. Copies of the test pit logs are included in Appendix A. As indicated on the logs, the zubsurface conditions at the site were fairly consistent. The test pits generally encountered up to 1.0 foot of topsoil above tan, moist, very stiff clay loam with gravel and cobble soils with a moderate blocky structure that extended to the bottoms of the excavations. The site soils are consistent with Soil Type 3 with less than 35Yo rock. Groundwater was not encountered in the subsurface at the time of the investigation. In general, based upon the results of the subsurface investigation, FIBET believes that the seasonal high groundwater elevation is deeper than 7.0 feet below the existing grade at this site. 2789 Riverside Parkuay Grand Jurction, Colorado 81501 Phone: 970-255-8005 Info@huddlestonberry. com P arcel 217 927 1 0 I 002 ADU #a22A5-00A2 05lnr25 Onsite Wastewater Treatment System A@ Iluddleson-Berry Ensift..iosC T.{hS, LLc Seepage Bed Design The design of the absorption $ystem generally follows the requirements of the Garfreld County Department of Public Works as outlined in the Garfield County On-Site Wastewater Treatment System Regtlations, effective July 2018. The proposed construction at the site is anticipated to include a single-bedroom ADU. However, Garfield County regulations require that a minimum of fwo bedrooms be considered per habitable structure. Therefore, the design will consider two bedrooms. Based upon visual-tactile evaluation of the site soils in accordance with the regulations, a Long- Term Acceptance Rate (LTAR) of 0.35 was utilized for the absorption field design. Infiltrator Systems Quick4 Standard Chambers are proposed. The daily flow of the sewage disposal system is calculated below and a plan and profile of the absorption system are shown on Figure 3. Average Daily Flow: (4 persons)(ls GPDlperson) :300 GPD Soil Treatment AreR : (300 GPD / 0.35): 858 Square Feet Adjusted Soil Treatment Area : (858 SFXI .2)(0.7):721Square Feet # of Quick4 Chambers : (721 / 12):60 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 Infiltrator 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 95a/o of the standard Proctor maximum dry density, within *TYo of optimum moisture content. However, up to 3-inches of washed rock or pipe bedding passing the l-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 +Za/a of optimum moisture content. Pipe bedding should have a maximum particle size of l-inch.. Vehicular or heavy equiprnent traffic and placement of structures should not encroach within 10 feet of the septic tank or distribution box. Inspection Schedule Huddleston-Berry Engineering & Testing LLC should be retained to monitor the construction of the OWTS. The following schedule of observation and/or testing should 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. Verify proper fall between inverts. 2V:U008ALL PRO.TECTS\0?:05 - Cr$et $Eiit$\02205'0002 Pdobl 217927101002 ,4Di-]1t00 - Ged$2?05-000? OWTS0.5I22.5.t&p P arcel ?1 7 927 I 0 1 002 ADU #02205-0002 05t12D5 lA@ Iluddleslon-Berry E tiftcriot& T.{hg, LLc . Observe and verify installation of the absorption bed prior to placement of cover and backfill. In conformance with Garfield County regulations, IIBET will be required to provide the Garfield County Health Department with documentation certifying that the OWTS was placed in conformance to the plan and profile and Garheld 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 Testingo LLC Wayne D. Anderson, P.E. Project Engineer JV:\2008 -{"1. PROJECTS\02:0.5 . Case}, Shiell\0?20.5'0002 Puc;l 2l ?,o27101m2 ADIi\200 ' Cdit0220.i.0002 O\!TSO51?25.tk* FIGURES G)qPublic.net'" GarfieJd County, Co Oate created: A5/2A25 Last Deta Uploaded: 2/5/2O25 2:O6:51 AM FIGURE 1 Site tocation Map o"*t.n"auv1p SCHNEIDER 9IO8PA'IAL Project No.: 02205-A002 Dale: 05112/25 BY: WDA t EXISTING STA NATURAL POND t_ \ I NEW STA/ EXISTING ROAD ROW AND UTILITY EASEMENT SCALE: 1" = 200' C.I. = l0 FT a'rusTPrT I EXISTING EXISTINGTANK*.. * EXISTINE STA'"r' "---\ SEPTICTANK WITH MINIMUM l,OOO GALLON CAPACITY \- ' -'/SCALE: l" - 60' NEW ADU SHOP WATJ LINE AREA .ilOfi ]ANh AM BEO LSTIONS APPFOT@E AND Nt SHFT SOM iUAilG CO{0ru(NON BTgED UFON 5IE TOro@ PHY ryNTR PREf! RENCE ANNR Q}IE R FIC'MS AS LW T9 AFPL&S!! SETgACK S ARE W T ACruA! $CAION OI TAI( AND 8FC W]LL BE NOICITEOONIS,E! LTOMWINGS' NEW STA S @l,l*s**ril PARCEL#2 17927 l0 1002 ADIJ FIGURE 2. SITE PI-AN DETAIL AREA **IJSE SWEEP 9O'S OR TWO 45'S .{T 90 DEGREE BENDS** SCALE: 1" = 30 f * INSPDCTION PORTS 4 ROWS OF 15 QtrJcK4 I}IFILTR,{TORS OR ENGINEER APPROVED EQUAI PORTS DISTRIBUIION BOXTHAT SEPfICTANKWITHENSURESEVEN OF EFFLUENI 1,000 GA.LLOI'{ CAPACITY 4-INCH DIAMETER SEWER AND EFFLUENT PIPE MSETING ASIM DI785, SCHEDULE dO OR SDR 35 WATER LINE Huddteston-Berry Enginecring & Tcsring, l-l,C 640 White Avenue. UnitB Grand Junction, CO 81501 PARCEL#2 17927 l0 1002 ADU FIGURE3. SEPTIC SYSTEM DETAII-S ProjectNo.: {J2205-0002 Date: 05/12/25 BY: WDA GENN,RALTZED SYSTEM PROFILE }IIT TII SCALE RE$!EI{TIAL SII(ETIRE EisT, a0 rt NAX' e qlPthilElrT slpnc Fnlt+ cFt€ aFDR!wE! LIST GENERALIT,ED BED PROFILE r{xlT T0 SCILE "l I I I I I I L FILTffi BED DIMENSIONS = ONE 12X60'BED 4 ROWS OF 15 QUICK4 STANDARD TNFILTRAT(XS ENGINEER APPRO\'ED EQU AL OR INFILTRATON, SYSTSMS QUICIi4 COVER SOIL; NATIVE SOILSOR OII{ER SUITABLE TOPSOIL. GRAD6 TO CARRY SURF'ACE WATERSTANDARI) BED. MEDLEPUNCHED, FABRIC IMMEDIATELY ABO\G CI{AMBERS MINIMUM SETBACKS (UNlTs= rD ffis $ o ! ucE"tDffi 5 5 ro 5 e0 urc, 'lflEnre[H 5! s s l@BE 1! EI s l.mM o I a 6Dm tr a l gElE D 6 o ru ! lfl t **OII{ER $TBACKS NOT LISTED HERE SIIOI,I"D BE IN ACCORDANCE WITH C.df.FIELD COUNfY OWTSREGULATIONS APPENDIX A Typed Test Pit Logs TEST PIT NUMBER TP-1 PAGE 1 OF 1 PRGTECT ]ttAME Parcel 717y2VOlAO2 ADLJ PROJEGT NUMBER OaW-ofp.Z PROJECT LOCATION sitr co CLIENT Casey Sheets Huddleston-Berry Engineering & Testing LLC 970-255-8005 Riverside Parhvay Junction, CO 81501 TEST PIT SIZEMTESTARTED 1N7N5 COMPLETED 1117N5 EXCAVATION CONTMGTOR Client CHECKEDBY MAB EXCAVAilON METHOD Trackh/Backhoe GROUNDELEVATION ATENDOFEXCAVATION Drv AFTEREXCAVATION .- LOGGEDBY TC NOTES GROUND WATER LA'ELS: ATTIMEOF EXCAVATION Drv ATTERBERG LIMITS ILo-€ a oo () +(9tqt-o MATERIAL DESCRIPTION ulL>trFul 5gL=r =2.a s E8 8sult EoJ co (/)oF=ZJ e5oz- zulLF6irr g ooI FF^ =Eto r-u baE:- -FJZ f.lt Yroz =oC) 9r e= J- oEF s=c F0il hCr-<=Jo FztrjFz Li -oC)Ca UJztr 2.5 50 Clay Loam with Gravel and Cobbles, tan, moist, very stiff, moderate blocky structure (Soil Type 3 < 35% Rock) oN a dooOq RNo azEfJoO-to-t)utFoU Bottom of test pit at 7.0 feet. Huddleston-Berry Engineering & Testing LLC 2789 Riverside Parkway C'rand Junction, CO 81501 970-255-8005 PROJECT MME Parcel 217W7 1 O1OUZ ADV PRG'ECT NUMBER O22O5.OOO2 PROJECT LOCATION Silt, CO CLTENT Casev Sheets TEST PIT NUMBER TP-z PAGE ,I OF 1 DATESTARTED 1117125 @MPLETED 1117125 TEST PIT SIZE EX$VATIONCONTMCTOR Client CHECKED BY r\4AB EXCAVATION METHOD Trackh/Backhoe GROUND ELB/ATION ATENDOFEXCAVATION Drv AFTEREXCAVATION --- LOGGEDBY TC I{OTES GROUND WATER LEVELS: AT TIMEOF EXCAVATION Drv ATTERBERG LIMITSLllo->04Fut 5go-=) =.2(D a qe gs LUtr (,)ul>FfAZ1;3soz zul o- F-Gixg ooo- 5 L =Ee.o r.rr bsE-- t/) gl -Foz>oo a, a= l- otrt 3=(L Fst 6e 5= Fz UJFz LJ€oe) s) ttJztr I IF(L ulA o.o o ftEt-o MATERIAL DESCRIPTION 2.5 EA Clay Loam with Gravel and Cobbles, tan, moist, very stiff, moderate blocky structure (Soil Type 3 < 350,6 Rock) FUq tn Jg) l Fz(, o-q at): fo Noo o Fq! N N Jlx IY L Noo a 6lNo Bottom of test pit at 6.0 feet. TEST PIT NUMBER TP.3 PAGE 1 OF 1 PRO.TECT lrlAME Parcel 21792.VO1 AO2 ADV PRO.JECT LOCATIONPROJECT NUMBER oz2ffi-Offi2 Rirerside Engineering & Testing LLC CLIENT Casev Sheets 970-255-8005 Junction, CO 81501 @MPLETED 1117125 TEST PIT SIZEDATESTARTED 1117125 CHECKED BY fvIAB EXCAVATION CONTRACTOR Client EXCAVATION METHOD Trackh/Backhoe GROUND ELEVATION AT ENDOF EXCAVATION Drv AFTEREXCAVATION -* LOGGEDBY TC t{oTEs GROUND WATER LBIEL$: AT TIME OF EXCAVATION Drv ATTERBERG LIMITSu.r SE:' tD lil -Foz>o C) r], a<fJ ()trF 3= o- Fqff 6a-<=JL FzulFzoG'()el @trjz l"L IE EF(Llllo o o Irho-X sYo MATERIAL DESCRIPTION ul(L>GFtU 5go-:IEz. aJ) s E<- ttHg5 trlv. oO>F= ^ZJx3soz zul(L FOilJ.9 Ooo- F^ 19, ao 1 ry.'.!i* r_t..J ?'*4 .r i; \r:-:.'? i:.g-t' it,a .rl 2."S-?. Clay Loam with Organics (TOPSOIL) 2 Clay Loam with Gravel and Cobbles, tan, moist, very stiff moderate blocky structure (Soil Type 3 < 3506 Rock) Bottom of test pit at 3,0 feet. Na Foo ni Jol t-z(t L Ju O E. Noooo RNo azFlJoo-d! Iotltt t!