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Home My WebLink AboutOWTS Design 2789 Riverside Parkway Grand Junction, Colorado 81501 Phone: 970-255-8005 Info@huddlestonberry.com March 29, 2022 Project#02388-0001 Shane Wade PO Box 425 Silt, Colorado 81652 Subject: OWTS Design 1650 County Road 237 Silt, Colorado Reference: Geotechnical Investigation, 1650 County Road 237, Silt, Colorado by Huddleston-Berry Engineering & Testing, LLC for Shane Wade, December 22, 2021. Dear Mr. Wade, At your request, Huddleston-Berry Engineering & Testing, LLC completed design of an Onsite Wastewater Treatment System (OWTS) for a single-family residence at 1650 County Road 237 in Silt, Colorado. The site location is shown on Figure 1 – Site Location Map. A site plan is included as Figure 2. Site Description At the time of the investigation, the site was open and gradually sloping down towards the east. Site topography is shown on Figure 2. Vegetation consisted of weeds, grasses, and small to large bushes and trees. The site was bordered to the north and east by residential/agricultural properties, to the south by 250 Road, and to the west by Harvey Gap Road. Subsurface Investigation As indicated in the referenced report, three test pits were excavated in the vicinity of the proposed Soil Treatment Area (STA). Test Pits TP-8 and TP-9 encountered 1.0 foot of topsoil above loamy sand with gravel and cobbles. Test Pit TP-10 encountered 1.0 foot of topsoil above silt loam. Groundwater was not encountered in the subsurface at the time of the investigation. In general, HBET believes that the seasonal high groundwater in the vicinity of the proposed STA is deeper than 6.0 feet. The locations of the test pits are shown on Figure 2. Copies of the test pit logs are included in Appendix A. 1650 County Road 237 #2388-0001 03/29/22 C:\HBET\Project Files\2022\02388-0001 1650 County Road 237\200 - Geo\02388-0001 LR032922.doc 2 Onsite Wastewater Treatment System Seepage Bed Design The design of the absorption system generally follows the requirements of the Garfield County Board of Health as outlined in the Garfield County On-Site Wastewater Treatment System (OWTS) Regulations, adopted June 2018. The proposed construction at the site is anticipated to include a four-bedroom home. Based upon visual-tactile classification of the site soils, a Long-Term Acceptance Rate (LTAR) of 0.6 will be 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 = (7 persons)(75 GPD/person) = 525 GPD Soil Treatment Area = (525 GPD / 0.6) = 875 Square Feet Adjusted Soil Treatment Area = (875 SF)(1.2)(0.7) = 735 Square Feet # of Quick4 Chambers = (735 / 12) = 62 Chambers; Use 64 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 (OWTS) 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 95% of the standard Proctor maximum dry density, within ±2% 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% of optimum moisture content. Pipe bedding should have a maximum particle size of 1-inch.  Vehicular or heavy equipment 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.  Observe and verify installation of the absorption bed prior to placement of cover and backfill. 1650 County Road 237 #2388-0001 03/29/22 C:\HBET\Project Files\2022\02388-0001 1650 County Road 237\200 - Geo\02388-0001 LR032922.doc 3 In conformance with Garfield County regulations, HBET will be required to provide the Garfield County Board of Health 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. Berry, P.E. Vice President of Engineering 03/29/22 FIGURES 2789 Riverside ParkwayGrand Junction, CO 81501Project No.: 02388-0001Date: 03/29/22By: MAB1650 COUNTY ROAD 237PART OF PARCEL 212725400042FIGURE 2 - SITE PLANAPPROX. TEST PIT LOCATIONC.I. = 2 FTSCALE: 1" = 60'03/29/22 GENERALIZED BED PROFILECOVER SOIL; NATIVE SOILS OR OTHER SUITABLETOPSOIL. GRADE TO CARRY SURFACE WATERAWAY FROM BED.NONWOVEN, NEEDLE PUNCHED, GEOTEXTILEFABRIC IMMEDIATELY ABOVE CHAMBERSGENERALIZED SYSTEM PROFILE2789 Riverside ParkwayGrand Junction, CO 81501MINIMUM SETBACKS(UNITS = FT)**OTHER SETBACKS NOT LISTED HERE SHOULD BE IN ACCORDANCE WITH GARFIELD COUNTY OWTS REGULATIONSINFILTRATOR SYSTEMS QUICK4STANDARD CHAMBERS**USE SWEEP 90'S ORTWO 45'S AT 90DEGREE BENDS**DETAIL AREASCALE: 1" = 30'Project No.: 02388-0001Date: 03/29/22By: MAB4-INCH DIAMETER SEWER ANDEFFLUENT PIPE MEETING ASTMD1785, SCHEDULE 40 OR SDR 35SEPTIC TANK WITHMINIMUM 1,250GALLON CAPACITYDISTRIBUTION BOXTHAT ENSURES EVENDISTRIBUTION OFEFFLUENTINSPECTION PORTSINFILTRATOR SYSTEMSQUICK4 STANDARD CHAMBERSINSPECTION PORTSNEW RESIDENCE1650 COUNTY ROAD 237PART OF PARCEL 212725400042FIGURE 3 - SEPTIC SYSTEMDETAILSWELLWATER LINE03/29/22 APPENDIX A Typed Test Pit / Perc Testing Logs Silt LOAM with Organics (TOPSOIL) Loamy SAND with Gravels and Cobbles (<35% rock), tan, moist, structureless Bottom of test pit at 6.0 feet. NOTES GROUND ELEVATION LOGGED BY SD EXCAVATION METHOD Trackh/Backhoe AT TIME OF EXCAVATION 5.5 ft AT END OF EXCAVATION 5.5 ft AFTER EXCAVATION --- TEST PIT SIZE EXCAVATION CONTRACTOR Client GROUND WATER LEVELS: CHECKED BY MAB DATE STARTED 11/10/21 COMPLETED 11/10/21 DEPTH(ft)0.0 2.5 5.0 GRAPHICLOGATTERBERG LIMITS MATERIAL DESCRIPTION SAMPLE TYPENUMBERFINES CONTENT(%)RECOVERY %(RQD)BLOWCOUNTS(N VALUE)POCKET PEN.(tsf)DRY UNIT WT.(pcf)MOISTURECONTENT (%)LIQUIDLIMITPLASTICLIMITPLASTICITYINDEXPLASTICITYINDEXPAGE 1 OF 1 TEST PIT NUMBER TP-8 CLIENT Shane Wade PROJECT NUMBER 02388-0001 PROJECT NAME 1650 County Road 237 PROJECT LOCATION Silt, CO GEOTECH BH COLUMNS 02388-0001 1650 CR 237 USDA.GPJ GINT US LAB.GDT 3/24/22Huddleston-Berry Engineering & Testing, LLC 2789 Riverside Parkway Grand Junction, CO 81501 970-255-8005 Silt LOAM with Organics (TOPSOIL) Loamy SAND with Gravels and Cobbles (<35% rock), tan, moist, structureless Bottom of test pit at 3.0 feet. NOTES GROUND ELEVATION LOGGED BY SD EXCAVATION METHOD Trackh/Backhoe AT TIME OF EXCAVATION dry AT END OF EXCAVATION dry AFTER EXCAVATION --- TEST PIT SIZE EXCAVATION CONTRACTOR Client GROUND WATER LEVELS: CHECKED BY MAB DATE STARTED 11/10/21 COMPLETED 11/10/21 DEPTH(ft)0 1 2 3 GRAPHICLOGATTERBERG LIMITS MATERIAL DESCRIPTION SAMPLE TYPENUMBERFINES CONTENT(%)RECOVERY %(RQD)BLOWCOUNTS(N VALUE)POCKET PEN.(tsf)DRY UNIT WT.(pcf)MOISTURECONTENT (%)LIQUIDLIMITPLASTICLIMITPLASTICITYINDEXPLASTICITYINDEXPAGE 1 OF 1 TEST PIT NUMBER TP-9 CLIENT Shane Wade PROJECT NUMBER 02388-0001 PROJECT NAME 1650 County Road 237 PROJECT LOCATION Silt, CO GEOTECH BH COLUMNS 02388-0001 1650 CR 237 USDA.GPJ GINT US LAB.GDT 3/24/22Huddleston-Berry Engineering & Testing, LLC 2789 Riverside Parkway Grand Junction, CO 81501 970-255-8005 Silt LOAM with Organics (TOPSOIL) Silt LOAM, brown, moist, blocky, moderate structure Bottom of test pit at 3.0 feet. NOTES GROUND ELEVATION LOGGED BY SD EXCAVATION METHOD Trackh/Backhoe AT TIME OF EXCAVATION dry AT END OF EXCAVATION dry AFTER EXCAVATION --- TEST PIT SIZE EXCAVATION CONTRACTOR Client GROUND WATER LEVELS: CHECKED BY MAB DATE STARTED 11/10/21 COMPLETED 11/10/21 DEPTH(ft)0 1 2 3 GRAPHICLOGATTERBERG LIMITS MATERIAL DESCRIPTION SAMPLE TYPENUMBERFINES CONTENT(%)RECOVERY %(RQD)BLOWCOUNTS(N VALUE)POCKET PEN.(tsf)DRY UNIT WT.(pcf)MOISTURECONTENT (%)LIQUIDLIMITPLASTICLIMITPLASTICITYINDEXPLASTICITYINDEXPAGE 1 OF 1 TEST PIT NUMBER TP-10 CLIENT Shane Wade PROJECT NUMBER 02388-0001 PROJECT NAME 1650 County Road 237 PROJECT LOCATION Silt, CO GEOTECH BH COLUMNS 02388-0001 1650 CR 237 USDA.GPJ GINT US LAB.GDT 3/24/22Huddleston-Berry Engineering & Testing, LLC 2789 Riverside Parkway Grand Junction, CO 81501 970-255-8005