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Home My WebLink AboutOWTS Installation Observation 08.03.2026August 3, 2026 502 Main Street, Suite A3, Carbondale, CO 81623 970-704-0311 Larry and Susie Brannon PO Box 2834 Santa Maria, California 93547 Barehunter17@hotmail.com C/O Alan Short, Woodstone Inc., alan@woodstoneinc.net RE: As-Constructed Report, On -site Wastewater Treatment System (OWTS), Larry and Susie Brannon Family Trust, Brannon Residence, 253 Shore Drive, Silt , Garfield County, CO SE Job No. 34132, Parcel N o: 217912401004. New Garfield County Permit # SEPT-9016 Dear Larry: Pursuant to County requirements, this letter provides documentation that the Onsite Wastewater Treatment System (OWTS) upgraded components recently installed at the above referenced site is in compliance with the permitted design. Sopris Engineering inspected the excavations, soils, materials and the installation of the system components during construction, prior to final backfill and after all installations were completed. The absorption field and pump dosing/ distribution component installations were designed and constructed to serve the proposed usage on the subject property. Sopris Engineering performed site visits to inspect and document the as -constructed conditions of the OWTS. Inspections were coordinated with the general contractor, Alan Short, Woodstone Inc. and the contractor that installed the system components. The as-constructed conditions and installation of the OWTS components is in compliance with Garfield County regulations and the specifications is delineated C1.0-OWTS As-Constructed Plan dated 08-03-2026, by Sopris Engineering. As-Constructed OWTS Conditions and Design Criteria The system was constructed to provide for demand dosing of septic tank effluent to an engineered soil treatment area (STA). The OWTS includes a gravity service pipe from the residential dwelling to a 1530- gallon plastic septic tank in series with a 540-gallon plastic dosing tank equipped with a Orenco System bio tube high head effluent pump assembly for pressure distribution of septic tank effluent to a new pressure dosed chamber trench system . The tanks were installed with ribbed PVC risers with fiber lids at the surface, inlet and outlet sanitary tee s, an Orenco Universal Biotube Pump Vault with a PF500511 pump, 1.5” discharge and 27” float stem assemblies in the dosing tank. An Orenco Systems S-1 Simplex CT ETM control panel was installed at the SE corner of the dwelling. Pump and control wires from panel to components, routed to the dosing tank riser external splice box are connected with silicon wire nuts. Septic tank effluent is pressure dosed to an infiltrator chamber trench system consisting of 4 chamber trenches, installed in native soils, with custom perforated distribution laterals set on the native soil absorptive surface. The 1.5” effluent discharge transport pipe was installed to an automatic distribution valve (ADV) (Orenco Model 6404) that has individual 1.5” distribution pipes connecting to the distribution laterals at the proximal end of each trench. The ADV provide for alternating demand dose to a single trench per dose cycle. Each trench has specified inspection ports and flush assemblies with appurtenances installed on the head and distal ends of each trench. OWTS As-Constructed Conditions Report Brannon, 253 Shore Drive, Silt, Garfield County Permit # SEPT-9106, SE Job No. 34132.01 August 3, 2026 Page 2 Final Inspection, System Testing and Startup Sopris Engineering performed a site visit on July 16, 2026, to inspect and verify operational function of the recently installed OWTS distribution components and testing performed in coordination with the contractor. SE inspected the OWTS to complete the required As-Constructed documentation for the record drawing, certification letter and to document that all previously listed Final Inspection Punch list items were addressed pursuant to the email by Garfield County, Julia Lee, dated 11-26-2025. On July 15, 2026 the contractor performed operation test in coordination with the engineer. The floats were manually operated to test the pumps on/off/alarm activation and to confirm that the high water visual/audible alarm is active. A squirt test was performed by observing the effluent height from each orifice in a threaded cap at all 4 distal end flush assemblies. The residual head squirt height was measured at 7.0’ (84”) from the level of the distribution laterals set at the absorptive surface in the trenches. The testing verified that the system is functioning as designed and can be set for automatic normal operation. The ADV inlet ball valve was adjusted to reduce the quirt height to 4’. Design Calculations OWTS The des ign is based on a 4-bedroom single family residence. The design flow was based on a total residential population of 7 persons. From County adopted State Regulation 43, Design Flow Criteria: Minimum population based on 2 persons per bedroom for the first 3 bedrooms and 1 person per each additional bedr oom. 4-bedroom Design capacity = 3 x 2 +1 = 7 persons @ 75 gal/person/day, Max. Design flow (Qd)gallons/day = (# of people) x (avg. flow)gal/person/day. Design flow Qd = 7 * 75 = 525 gpd Septic Tank Design: 2-Day detention time = 525 x 2 = 1050 gallons required. Used a 1530-gallon, two compartment plastic detention tank in series with a 540-gallon , one compartment plastic dosing tank with a high head pump assembly. Sub Surface Conditions and Testing Additional soil evaluations were performed by the engineer during construction to verify the soils in the entire STA field excavation during installation of the OWTS components. The observed soils in the trenches within 3 -feet of the existing surface grades and tank, within 8-feet of the existing surface grades excavations were consistent with the descriptions above and consists of sandy silt loam. No rocky soils or change of texture was encountered at depth. The soils are characterized as USDA soil type 2 consisting of sandy silt texture with granular structure and moderate to strong grade. This soil has an effective loading rate for conventional soil treatment of 0.60 Gal/S.F./day for a level 1 conventional treatment system. A Subsurface soil investigation was previously performed by Kumar USA on December 17, 2024 in order to develop recommendations for the foundation, floor slab and potential groundwater mitigation design. The subsoil conditions in the area of the proposed dwelling structure were evaluated from soil samples OWTS As-Constructed Conditions Report Brannon, 253 Shore Drive, Silt, Garfield County Permit # SEPT-9106, SE Job No. 34132.01 August 3, 2026 Page 3 obtained from two drilled exploratory boring holes. Samples of the subsoils obtained during the field exploration were tested in the laboratory to determine their classification, compressibility, natural moisture content, density, and finer than sand size gradation analyses and other engineering characteristics. The subsurface profile encountered in the borings consists of very stiff, slightly clayey, slightly sandy to sandy silt down to the maximum depth drilled of about 25 to 30 feet. No limiting soil or hydrological conditions were encountered. The soils below 6 inches of topsoil consist of stiff sandy silt. Based on the testing results, existing topography, vegetation and observation of site features the soils appear and are assumed to be consistent across the site. From the results of the tests performed and presented in Kumar's subsoil study report, the soils from 2 -3 feet below the surface are consistent with a USDA soil type 2 consisting of sandy silt texture with granular structure and moderate to strong grade. Observation and sampling of the boring spoils by the engineer indicate presence of soil type 2 sandy silt with granular structure and moderate grade. No free water was encountered in the borings on site. Normal Groundwater levels are expected to be below 10 feet from the existing surface grades. Chamber Treatment Unit/ Absorption System Design The soil treatment area was designed based on utilizing the effective Long Term Acceptance Rate (LTAR) for native soils and the application of appropriate loading factors for a treatment level-1 system utilizing pressure dosed chamber trenches . Long Term Acceptance Rate (LTAR) Receiving septic tank effluent, a treatment level-1 Maximum hydraulic loading rate for TL1 effluent is 0.6 gal./S.F./day) (Table 10 -1) being the long-term acceptance rate of the Type 2 receiving soil. A(sf) = Qd x L.F.1 x L.F.2.: A = Area; LTAR LTAR = 0.6 gal/S.F./day for silt loam Qd = flow (gal/day) for OWTS = 525 gpd L.F.1=0.8 pressure dosed trench application L.F.2=0.7 Gravelless chambers Category 3 distribution media OWTS: A(sf) = 525 gpd x 0.8 x 0.7 = 490 S.F. 0.6 Gal/S.F./day Number of Quick -4 Infiltrator chambers 4'x3'x12"chambers: 490 S.F = 41 Infiltrator Quick-4 chambers; Use 44 chambers 12 S.F./Chamber Installed 44 Quick-4 Infiltrator chambers in 4 trenches 46' long by 3' wide with 11 chamber units per trench plus two end caps as delineated on the plan. A 4" vertical inspection port riser was installed from the molded penetration port on each chamber end cap in the trench. OWTS As-Constructed Conditions Report Brannon, 253 Shore Drive, Silt, Garfield County Permit # SEPT-9106, SE Job No. 34132.01 August 3, 2026 Page 4 Effluent Distribution System The septic tank effluent is pressure discharged to a automatic distributing valve (ADV), installed at a highpoint adjacent to the proximal end of the southerly trench , via a 1.5” transport pipe from the high head pump discharge assembly in a biotube filter vault set in the single compartment of the 500-gallon dosing tank. The minimum slope of the transport pipe from the tank's dosing compartment to the automatic distributing valve w as installed at a minimum 2% slope to allow for drain back to the tank. The distribution system was installed for effluent to be equally distributed across the absorptive surface in each trench via individual custom perforated pressure distribution laterals connected to the distribution pipes from the ADV. The distribution laterals were installed on the infiltrative surface, under the chambers, along the entire length of each trench. The 3/16 -inch orifices w ere drilled on 2’ centers oriented upward along the length of the distribution lateral. A ball valve was installed on the terminal end of each distribution lateral extended vertically adjacent to the 4” inspection port from the distal end cap, housed in a 10" valve box with lid set 2" above surface grades. OWTS Operation and Maintenance The floats were set pursuant the original design intent performance specifications with respect to the dosing tank, piping and STA configuration as -constructed conditions. The performance calculations are presented on the Record drawing. The dosing volume is approximately 58 gallons per cycle. All components of the engineered OWTS shall be inspected on a regular basis and be properly maintained. The responsibility for repair and maintenance of the system will remain with the property Owner. The owner shall retain the services of qualified personnel to inspect the OWTS and to perform all maintenance and repairs necessary to ensure that the system is in good operating condition and is in compliance with the manufacturer’s performance requirements. The operating components of the OWTS should be inspected every six months by the owner or qualified service provider. In general, for a properly utilized system, septic tanks should be pumped every 3-5 years. The effluent filter should be cleaned every six months and at the time of pumping. Absorption fields should be maintained with suitable vegetative cover and kept free of root invasive plants. Positive s urface drainage away from the absorption field should be maintained. If you have any question or need any additional information, please call. Sincerely, SOPRIS ENGINEERING, LLC Paul E. Rutledge Yancy Nichol, PE Design Engineer Principal 8/3/2026