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Home My WebLink AboutAs-built Report 12.02.2019December 2, 2019 Dave Heyl Heyl Construction 6560 C.R. 335 New Castle, CO 81647 "Dave Heyl" <d.heyl@heylcivil.com> RE: As -Constructed, Onsite Wastewater Treatment System (OWTS) Record Report — Lot 3, Oak Meadows Subdivision Filing 3, 75 Oak Crest Lane, Glenwood Springs, Garfield County, CO SE Job No. 13098.02 Parcel No: 2645-273-00-004, Garfield County Permit No. SEPT -03-19-5696 Dear Dave: Pursuant to County requirements, this letter provides documentation that the new Onsite Wastewater Treatment System (OWTS) 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 at various times during construction, prior to final backfill and after all installations was completed. The system constructed on site was designed and built to serve the needs of the single family residential structure and accessory garage/shop building. The installed residential system was designed for a maximum 4 -bedroom residence. Sopris Engineering performed site visits to inspect and survey the as built conditions of the constructed system in coordination with Dave Hyle, Hyle Construction. The as built conditions and installation of the new OWTS components are in compliance with County Regulations; the recommendations and specifications delineated on the civil design plans, C2.0 OWTS Plan and C2.1 OWTS Details, dated March 19, 2019, designed by Sopris Engineering. The design criteria and system sizing information is summarized below. An As -Constructed OWTS record drawing is attached delineating the As -built descriptions and location of the components. The OWTS was constructed and completed in October of 2019 by Hyle Construction, 6560 County Road 335, New Castle, CO 81647, p. 970.230.5822 OWTS Design Criteria and Sizing The OWTS is designed for a treatment capacity of 525 gallons per day based on the design wastewater flow to serve a 4 -bedroom residence in accordance with Table 6-2 values, Section 43.6, A.4. The building improvements included a 4 -bedroom dwelling with a Shop Garage facility that includes a 1/2 bath to be served by the new OWTS system. The system was designed pursuant to current County design criteria approved for the use of a pressure dosed sand filter (SF) system based on the LTAR loading rate for ASTM -33 filter sand sized for a minimum equivalent 4 - bedroom flow capacity. The OWTS includes the installation of a 2,000 gallon 3 -compartment concrete septic tank that provides 1,500 gallon capacity in the first and second compartments. The tank is equipped with an Orenco Systems biotube assembly with duplex high head pumps installed in the third chamber with associated piping and controls. The 672 S.F. treatment/absorption SF field SF field consists of two beds installed to provide for alternate equal pressure distribution of effluent across each 336 S.F. bed. The SF beds were installed with 36 -inches of filter sand below graveness chamber spray shield units. The effluent is dosed across the two distribution rows in each bed via an individual custom perforated pressure distribution pipe running the length of each 42 feet by 8 feet beds. 502 Main Street • Suite 113 • Carbondale, CO 57623 • (970) 70e7-0377 • Fax (970) 70cf-0373 SOPRIS ENGINEERING •LLC civil consultants Dave Heyl —AC-OWTS Record Report 75 Oak Crest Lane, Glenwood Springs SE Job No. 18206.02 December 2, 2019 Page 2 Sub Surface Conditions and Observation A site specific subsurface soil evaluation was performed by Sopris Engineering, in March, 2019, in the vicinity of the proposed OWTS field. The soils below nil to 12 inches of topsoil consist of medium dense sandy clay loam from 1.0 to 6 feet below the surface. The soil appears to be consistent in both profile excavations and across the site. The native soils sampled from 2-6 feet below the surface are characterized as a soil type 3 consisting of sandy clay loam texture with moderate granular structure. The tactile soil test ribbons were over 1 -inch long however they did not exceed 1 % inch. The type 3 soil has a theoretical effective loading rate for conventional soil treatment of 0.35 Gal/S.F./day for a level 1 conventional treatment system and 0.80 Gal/S.F./day for a level 3 secondary treatment system with a 36" depth sand filter layer. Due to terrain topography and to provide optimal treatment an intermittent sand filter was installed that will treat effluent to a Level 3 treatment quality prior to infiltration into the native soil. No free water was encountered in excavations on site. Groundwater levels are expected to be below 10 feet from the existing surface grades. The soils are suitable for the installation of a sand filter treatment bed system that will be fully pressure dosed and utilize 36 -inches of washed concrete sand. OWTS Design Flow Calculations The onsite wastewater treatment system (OWTS) is designed with the capacity to serve a 4 -bedroom residence. From Garfield County/Regulation 43 usage table : Minimum population based on 3 bedrooms = 6 persons. Additional population based on bedrooms assuming 1 person per bedroom. Gallons per day per person =75 gal/person/day, No peaking factor. 3 bedrooms x 2 persons/bedroom + 1 additional bedroom x 1 person/bedroom = 7 persons Max. Design flow (Qd)gallons/day = (# of persons) x (avg. flow)gal/person/day. Design flow Qd = 7'75=525 gpd Septic Tank Design: Volume (V) of tank = Design Flow (Qd) x 2 (48 hour -2 day retention time) V = 525 gal/day * 2 = 1050 Installed a 2000 gallon, 3 -compartment septic with 1500 gallons of capacity in the 1st and 2nd chambers, Intermittent Sand Filter Treatment Unit/ Absorption System Design The treatment/absorption field is designed based on utilizing the effective Long Term Acceptance Rate (LTAR) for an intermittent sand filter treatment system utilizing pressure dosed distribution laterals and gravelless chamber units as spray shields. Long Term Acceptance Rate (LTAR) A(sf) = Qd x L.F.: A = Area; Qd = flow (gal/day) = 525 gpd LTAR L.F.1=1.0 pressure dosing LTAR = 0.8 gal/S.F./day for treatment level 3 sand filter utilizing 36" washed ASTM -33, filter secondary sand A(sf) = 525 gpd x 1.0 = 660 S.F. 0.8 gal/S.F./day Dave Heyl —AC-OWTS Record Report 75 Oak Crest Lane, Glenwood Springs SE Job No. 18206.02 December 2, 2019 Page 3 Installed two 42' by 8' beds excavated to a maximum 5' depth below finish grade surface and backfilled with 36 - inches of ASTM -33, washed concrete sand. Installed 2 rows of custom perforated 1.25 -inch distribution lateral on top of sand layer in each bed and covered with 9 Quick -4 chambers per row for use as pressure dose spray shields, as delineated on the plan. The beds are alternately dosed from the duplex high head distribution pump system installed in the third compartment of the new septic tank. The standard Quick 4 chamber spray shields were installed over the top of the sand on 4 -foot centers and backfilled with a minimum 12 -inch depth of cover. Filter fabric was placed over the chambers and the entire extents of the sand filter bed. The slightly mounded beds were constructed with 3 -inch topsoil layer placed over the field surface. OWS Operation and Maintenance Responsibility for maintenance and repair of the installed OWTS will remain with the property Owner. The Owner is encouraged to retain the services of qualified personnel to inspect the OWTS and to perform all maintenance and repairs necessary to ensure that the system components are maintained in good operating condition and suitable vegetative cover is established on the fields. The components of the OWTS system should be inspected within 30 days of being placed into operation and should be inspected and maintained bi-annually. The tank, absorption field and other system components should be visually inspected bi-annually for debris, damage, leaks, or other potential problems. In general, for a properly utilized system, septic tanks should be pumped every 2 - 4 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 surface 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 Design Engineer