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HomeMy WebLinkAboutAs-built Report & Plans 02.02.2021February 2, 2021 James P & Kelly Jonas Cleaver 3724 County Rd 115 Glenwood Springs, Co 8160I RE: As-Constructed—Onsite Wastewater Treatment System (OWTS), Cleaver Residence, 3724 C.R. 115, A Tract in Lot 1 Sec 20, Lots 3 & 8, Section 29 T6s R88w 6th PM, Garfield County, Colorado SE Job No. 30169.01 Parcel No: 2187-292-00-077, Previous Garfield County ISDS Permits: 1094&1852 Current Garfield County OWTS Permit: SEPT-10-20-6528 Dear James and Kelly: 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 replacement absorption field and tank installations were designed and constructed to serve the existing 5-bedroom residential property. Sopris Engineering performed site visits to inspect and document the as -constructed conditions of the OWTS. Inspections were coordinated with the property owner and the Contractor, Great Lakes Construction that installed the replacement system components. The as -constructed conditions and installation of the upgraded and new OWTS components is in compliance with Garfield County Regulations; the recommendations and specifications delineated on the civil C 1 OWTS plan drawing dated 10-07-2020 and the OWTS design Report dated 10-08-2020 by Sopris Engineering. The design criteria and system sizing information is summarized below. The As -Constructed OWTS components were completed as delineated on the design construction document plan previously submitted for permit. Summary Design Criteria The waste flow from the existing residence had been served by an OWTS permitted at the time of building permit in 1981, under County ISDS permit No. 1094 to serve a 2-bedroom residence and upgraded in 1990, under County ISDS permit No. 1852 to serve a total 5-bedroom equivalent residence. The recently installed OWTS provided for the addition of another septic tank, upgrade of an existing tank's access risers and replacement absorption field for a treatment capacity of 600 gallons per day based on the design wastewater flow to serve a 5-bedroom residence in accordance with Table 6-2 values, Section 43.6, A.4. The replacement OWTS utilizes the existing 1,000 gallon single compartment concrete septic tank and a new 1,060 gallon 2-compartment reinforced plastic septic tank installed in series longitudinal adjacent to the existing tank within the lawn area west of the primary dwelling structure. The existing 1,000 gallon septic tank outlet pipe, raw gravity sewer inlet pipes, from primary dwelling and ADU were excavated to the tank lid and below the pipe inverts for inspection, resetting of sanitary tee and installation of pipe connections. The original 750 gallon tank and connecting pipe was abandoned in place. New ribbed PVC risers with fiber lids were installed on the existing septic tank along with appropriate pipe connection to the new tank in series. The new 1,060 gallon 2-compartment reinforced plastic septic tank was installed with appropriate sanitary tees, outlet effluent filter with risers and lids at the surface. A gravity schedule-40 or SDR 35 sewer pipe section with two-way cleanout was installed between the existing tank inlet on the gravity sewer line and the primary dwelling. An additional cleanout has been installed on the new effluent outlet pipe from the new secondary septic tank in series at the grade break on the driveway embankment. A gravity schedule-40 or SDR 35 effluent pipe from the new 502 Main Street • Suite A3 • Carbondale, CO 81623 • (970) 704-0311 • Fax (970) 704-0313 SOPRIS ENGINEERING • LLC civil consultants Cleaver Residence, 3724 C.R. 115 As Constructed OWTS SE Job No. 30169.01 February 2, 2021 Page2 septic tank was installed to the new replacement STU absorption field with appropriate stepped fittings and cleanouts as needed to a new distribution box at the head of the field. The new replacement soil treatment unit (STU) consists of leaching chamber trenches that provide 840 S.F. of total absorption area. The septic tank effluent is gravity discharged through a new 4-inch schedule-40 or SDR-35, installed at variable slope, to the STU via a distribution box. The effluent is equally distributed from the distribution box via 4" distribution pipes connected to the head end cap of each of the 4 chamber trenches. Observation ports with caps were installed on each end chamber unit. The design is in compliance with the current County regulations with design calculations based on the soil type, texture and structure with an appropriate long term acceptance rate (LTAR). The system meets all required setbacks and has been installed within the general location indicated on the plan_ The existing well serving the residence, (Permit No. 113117) is located over 300 feet East Southeast of the field area. The design is outlined below and delineated on the attached C-1 As -Constructed OWTS plan. Design Flow The replacement OWTS is designed for a treatment capacity of 600 gallons per day based on the following design criteria: Minimum population based on 2 person per bedroom for the first 3 bedrooms = 6 persons and 1 person per bedroom for each additional 2 bedrooms = 2 persons for a total of 8 persons. 75 gal/person/day, No PF Max. Design flow (Q(1)gallons/day = (# of people) x (avg. flow)gal/person/day. Design flow Qd = 8*75=600 gpd. Septic Tank Design The septic tank capacity required for a minimum 48 hour retention time is calculated as follows: V = 600 gal/day * 2 = 1,200 gallons. Using the existing 1,000 gallon, single compartment concrete tank and a new 1,060 gallon 2-compartment reinforced plastic septic tank installed in series for a total septic tank capacity of 2,060 gallons. Tanks installed with sealed ribbed PVC risers and fiber glass lids set to the finish grade surface. The original 750 gallon tank was pumped, breached, partially crushed and backfilled for abandonment in place. Sub Surface Conditions and Observation A subsurface soil investigation and site assessment was performed by Sopris Engineering in on October 15, 2020. The soils from two profile pits, in the vicinity of the proposed STU field envelope area were sampled and characterized by application of the USDA visual/tactile soil texture method analysis. The soils below 18- 24 inches of topsoil consist of medium dense silt loam soil with less than 2% scattered gravel or rock content to 8 feet below the surface grades. The soils appear to be consistent across the site from observations in the excavated profile pits. The native soils sampled from 2-5 feet below the surface are characterized as a soil type 2 to type 2A consisting of silt loam texture with fine granular to weak massive structure. This soil has an effective loading rate for conventional soil treatment of 0.5 Gal/S.F./day for a level 1 conventional treatment system. The soils from 5-7 feet below the surface are characterized as a soil type 2A consisting of slightly sandy silt loam texture with weak massive structure having an effective loading rate of 0.5 Gal/S.F./day for a level 1 conventional treatment system. The soils below 7' to the depth of the 8.5 deep profile pit consist of slightly sandy silt loam with massive structure and slight evidence of mottling speckles, indicating minor redox conditions from infrequent maximum high ground water conditions below 7 feet from surface. No free water was encountered in the two profile pit excavations on site near the proposed STU area. Normal Seasonal high Groundwater levels are expected to be below 10 feet from the existing surface grades. Cleaver Residence, 3724 C.R. 115 As Constructed OWTS SE Job No. 30169.01 February 2, 2021 Page3 The soils are suitable for a shallow conventional shallow absorption field consisting of gravelless infiltration chamber units. Treatment -Soil Treatment Unit/ Absorption System Design The shallow STU trenches were installed with a maximum depth to the absorptive surface of 36 inches from finish surface grades and backfilled with approximately 3-inches of final grading topsoil mounded over the trenches placed to allow positive drainage away from the surface. Chambers were installed level in native soil. Each tipiich was constructed level along the contours with successive trenches installed following natural contour grades accordingly. A minimum separation distance of 4 feet was maintained between the individual trench sidewalls. Prior to installation, the Engineer inspected the trench excavation to confirm soil conditions and installation procedures. All septic system components and trench installations were approved by the Engineer prior to backfilling. Photo documentation by Engineer and Contractor have not been recovered or found due to phone loss and cloud storage failure. Field Sizing: Long Term Acceptance Rate (LIAR) Considering the application of the state regulation 43: Receiving Wastewater Treatment Level 1; Soil type 2A loading rate for silt loam with weak massive structure is (0.5 gal./S.F./day). Loading factors; (Table 10-2, Gravity application trenches = 1.0) and (Table 10-3, gravelless chambers = 0.7) A(sf) = Qd x L.F.1 x L.F.2 .: LTAR A(sf) = 600 gpd x 1.0 x 0.7 = 840 S.F. 0.5 Gal/S.F./day A = Area; LTAR = 0.5 Gal/S.F./day for silt loam Qd = flow (gal/day) = 600 gpd L. F.1=1.0 Gravity Distribution L.F.2=0.7 Chambers Number of ADS Arc-36 leaching chambers 5'x3'x12"chambers: 840 S.F = 56 chambers; Installed 70 chambers 15 S.F./Chamber STU Layout A total of 56 ADS Arc-36 leaching chambers chambers were installed in four trenches 70' long by 3' wide with 14 chamber units per trench plus end caps as delineated on the plan. OWS Operation and Maintenance Ownership of the system and responsibility for maintenance and repair 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 Cleaver Residence, 3724 C.R. 115 As Constructed DWTS SE Job No. 30169.01 February 2, 2021 Page4 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 3 - 5years. 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, TIP Paul E. Rutledge Design Engineer Yancy Nichol, PE Principal a .4 EXISTING 4" PVC GRAVITY SEWER PIPE INSTALL 1060 GALLON 2-COMPARTMENT INFILTRATOR SEPTIC TANK WITH SEALED RISERS AND LIDS INSTALLED AT THE FINISHED GRADE SURFACE. INSTALL INLET SANITARY TEE AND OUTLET EFFLUENT FILTER SANITARY TEE. DEPTH TO TOP OF TANK FROM PROPOSED GRADE 15 APPROXIMATLEY 30", INSTALL INTERMEDIATE CLEAN OUT AT TOP OF GRADE BREAK 4" EFFLUENT PIPE TO DISTRIBUTION BOX SDR-36@ MIN. 2% WITH 45° GRADE BREAK STEPS WITH CLEAN OUTS - s _ 10' OFFSET & UTILITY EASEMENT PROPERTY LiNE CONCRETE 7-PORT OUTLET DISTRIBUTION BOX W/ BAFFLE INSTALLED LEVEL ON COMPACTED BASE. INSTALLED RISERS & LID TO SURFACE GRADE 4" PVC DISTRIBUTION PIPES (TYP.) TO HEAD OF EACH TRENCH END CAP INSTALLED 4" RISER PIPE INSPECTION PORT EXTEND RISER W/ CAP MIN. 1" ABOVE FINISH GRADE (TYP. EACH CHAMBER END CAP) EX 750-GALLON SEPTIC TANK WAS PUMPED. THE RISER & LiD WAS REMOVED AND THE THAK WAS BACKFILLED &ABANDONED IN PLACE ABSORPTION/TREATMENT FIELD 7D QUICK-4 CHAMBERS IN 2 TRENCHES WITH 18 CHAMBERS UNITS PER TRENCH AND IN 2 TRENCHES WITH 17 CHAMBERS UNITS PER TRENCH FOR A TOTAL ABSORPTION AREA OF 840 S.F. THE BOTTOM OF EACH TRENCH WAS EXCAVATED TO AN AVERAGE DEPTH OF 30 INCHES BELOW THE EXISTING SURFACE GRADES, WITHIN THE UPPER HORIZON OF THE NATIVE SILT LOAM SOILS & BACKFILLED WITH A MINIMUM 12-INCHES OF COVER OVER THE CHAMBERS. THE FINISH GRADE ACROSS THE FIELD WA5 SLIGHTLY MOUNDED ABOVE EXISTING ADJACENT GRADES. rMMPRavL:.te.N; APARCFJ-OF LAND SITUATED Irj GOV t LEY: I, SECTION 20I..ioF'r LOPS A.1)H_;'r... IO' 29 TOH'VSh1P6 Sd1tx, R.1AI(;E RI WEST OF THl6IH P M. Cdtte toFrlvFE.V.STATE OF COLORAbf1 I_ f PEAK\ Sun cyies, Ice -.... PREVIOUS SURVEY PLAT EXISTING 1-BEDROOM STUDIO EX PATIO 4" PVC SEWER PIPE @ 2%, USE SCHD-400R 5DR-35 4" PVC EFFLUENT PIPE @ MIN. 1 %, U5E SCHD-40OR SDR-35 INSTALLED CHAMBER ENDCAPS (TYP.) INSTALLED NEW 24" DIA BY 30" TALL RIBBED PVC RISERS WITH FIBER LIDS (TYP) EXISTING 1000-GALLON SEPTIC TANK INSTALLED NEW PIPE CONNECTIONS & SANITARY TEES INSTALL NEW TWO-WAY CLEAN OUT EXISTING 4" PVC GRAVITY SEWER PIPE WITH EXISTING INTERNAL CLEANOUT EXISTING 4-BEDROOM HOUSE INSTALLED4" RISER PIPE INSPECTION PORT EXTEND RISER W/ CAP MIN. 1" ABOVE FINISH GRADE (TYP. EACH CHAMBER END CAP) APPROXIMATE LOCATION PROFILE PIT (TYP) APPROXIMATE LOCATION EXISTING ABSORPTION FIELD CHAMBER BED ABANDONED IN PLACE. OWTS DESIGN PLAN pI„p�vr ;�.TY EXISTING WELL, PERMIT 4 113117, PROVIDING WATER TO THIS PROPERTY LOCATED APPROXIMATELY 300' EAST SOUTH EAST FROM PROPOSED OWTS FIELD SHOWN GRAPHIC SCALE t IN FEET) ] inch = 20 ft. VINCINITY AERIAL MAP 61' MIN. 1 4" MiN. 1060 Gallon - 2CP infiltrator@ Poly Tank Risers to Grade ►can aoar • Compllent with CSA and IAPAO Standards • Insulated Iks avellohle • Maximum burro! depth Is 48' • I11"Imum Iwrfol depth ie 8' • 'Fmk Fe net read for vehrouldr ttofflo loading • Exterior of manhole cover Includes the folio-Med waelry 'DANGER DO NOT ENTER! POISON GASES 12' Lang x 7' Wide Mid -Height Seam Section Inlet 4r Olmenelona Length 127- Width 622' Heigh t 54. 7' Net Capoclty 320 Ibs REINFORCED PLASTIC SEPTIC TANK DETAIL NATIVE, YARD OR LANDSCAPED SURFACE Design Calculations OWTS Design Flow The design flow is calculated as follows for the total current and anticipated future waste flows of the existing single family dwelling. The replacement OWTS is designed for a treatment capacity of 600 gallons per day based on the design wastewater flow to serve a 5-bedroom capacity residence in accordance with Table 6-2 values, Section 43.6, A.4. Regulation 43: Minimum population based on 2 person per bedroom for the first 3 bedrooms = 6 persons and 1 person per bedroom for each additional 2 bedrooms = 2 persons fora tot& of 8 persons. 75 gal/person/day, No PF Max. Design fiow (Qd)gallons/day = (# of people) x (avg. flow)gai/person/day. Design flow Qd = 8* 75=600 gpd Septic Tank Design The septic tank capacity required for a minimum 48 hour retention time is calculated as follows: V = 600 gal/day * 2 = 1,200 gallons. Use the existing 1,000 gallon, single compartment concrete tank and a new 1,060 gallon 2-compartment reinforced plastic septic tank installed in series for a total septic tank capacity of 2,060 gallons. All tank to be installed with sealed ribbed PVC risers and fiber glass lids set to the finish grade surface. The original 750 gallon tank will be pumped, breached, partially crushed and backfilled for abandonment in place. Sub Surface Conditions and Observation A subsurface soil investigation and site assessment was performed by Sopris Engineering in on October 15, 2020. The soils from twa profile pits, in the vicinity of the proposed STU field envelope area were sampled and characterized by application of the USDA visual/tactile soil texture method analysis. The soils below 18- 24 inches of topsoil consist of medium dense silt loam soil with less than 2% scattered gravel or rock content to 8 feet below the surface grades. The Soils appear to be consistent across the Site from observations in the excavated profile pits. The native soils sampled from 2-5 feet below the surface are characterized as a soil type 2 to type 2A consisting of silt loam texture with fine granular to weak massive structure. This soil has an effective loading rate for conventional soil treatment of 0.5 Gal/S.F./day for a level 1 conventional treatment system. The soils from 5-7 feet below the surface are characterized as a soil type 2A consisting of slightly sandy silt loam texture with weak massive structure having an effective loading rate of 0.5 Gal/S.F./day fora level 1 conventional treatment system. The soils below 7' to the depth of the 8.5 deep profile pit consist of slightly sandy silt loam with massive structure and slight evidence of mottling speckles, indicating minor redox conditions from infrequent maximum high ground water conditions below 7 feet from surface. No free water was encountered in the two profile pit excavations on site near the proposed STU area. Normal Seasonal high Groundwater levels are expected to be below 10 feet from the existing surface grades. The soils are suitable for a shallow conventional shallow absorption field consisting of gravelless infiltration chamber units. Treatment -Soil Treatment Unit/Absorption System Design The treatment/absorption field is designed based on utilizing the effective Long Term Acceptance Rate (LTAR) for the native soils and the application of appropriate loading factors for a soil treatment unit system utilizing gravity distribution to gravelless chamber trenches. The new treatment system and absorption field will consist of gravity distribution of septic tank effluent via a distribution box to individual chamber trenches with treatment across the native soil absorptive surface. The shallow STU trenches shall be installed with a maximum depth to the absorptive surface of 36 inches from finish surface grades and backfilled with approximately 3-inches of final grading topsoil mounded over the trenches placed to allow positive drainage away from the surface. Chambers shall be installed level in native soil. Each trench will be constructed level along the contours with successive trenches installed following natural contour grades accordingly. A minimum separation distance of 4 feet will be maintained between the individual trench sidewalls. The engineer, prior to installation shall inspect the trench excavation to confirm soil conditions and installation procedures. All septic system components and trench installations are to be approved by the Engineer prior to backfiliing. Field Sizing: Long Term Acceptance Rate (LTAR) Considering the application of the state regulation 43: Receiving Wastewater Treatment Level 1; Sail type 2A loading rate for silt loam with weak massive structure is (0.5 gal./S.F./day). Loading factors; (Table 10-2, Gravity application trenches = 1.0) and (Table 10-3, gravelless chambers = 0.7) A(sf) = Qd x L.F.1 x L.F.2 .: LTA R A = Area; LTAR = 0.5 Gal/S.F./day for silt loam Qd = flow (gal/day) = 600 gpd L.F.1=1.0 Gravity Distribution L.F.2=0.7 Chambers A(sf) = 600 gpd x 1.0 x 0.7 = 840 S.F. 0.5 Gal/S.F./day Number of Quick-4 infiltrator chambers 4'x3'x12'chambers: 840 S.F = 70 chambers; Use 70 chambers 12 S.F./Chamber 5TU Layout A total of 70 Quick-4 infiltrator chambers were installed in two trenches 70' long and two trenches 74' long each by 3' wide with 17 and 18 chamber units per trench respectively plus two end caps as delineated on the plan or equivalent Arc/Bio-Diffuser chamber trenches. CONNECT INDIVIDUAL 4" DISTRIBUTION PIPE TO HEAD OF EACH CHAMBER TRENCH (TYPICAL EACH TRENCH). INSTALL CONNECTION AS NEEDED FROM END OR SIDE INLET PORT OF EACH INFILTRATOR CHAMBER END CAP. CHAMBER END CAP CHAMBER END CAP CONNECTION DETAIL EXCAVATED MATERIAL COMPACTED TO 9D% STANDARD PROCTOR SUITABLE BACKFILL OR I# CLASS 6 ROAD BASE COMPACTED SUBGRADE TRENCH CROSS-SECTION FOR SDR-35.26 OR SCHD-40 PIPES 4" SOLID PVC GRAVITY DISTRIBUTION PIPES (TYP.) TO ABSORPTION FEILD BACKFiLL WiTH SCREENED ONSITE 501L5 FREE OF ROCKS IN EXCESS OF 3" DIAMETER OR USE 3/4" TO 1.5' SCREENED ROCK FILTER FABRIC BACKFILL LAYER NATURAL ONSiTE SOILS FREE OF ROCKS SCARIFY/TILL BOTTOM SURFACE TO OF 3'' AND PLACE MIN. 3" OF ASTM SAND LEVELING COURSE. A DEPTH -33 NOTE: ALL CHAMBERS iN EACH TRENCH MUST BE INSTALLED ON LEVEL GRADE OVER 3" ASTM-33 FILTER SAND LEVELING COURSE. MAXIMUM DEPTH OF TRENCHES NOT TO EXCEED 36" BELOW PROPOSED SURFACE GRADES. INLET AND END CAPS ARE TO BE INSTALLED ON EACH END CHAMBER ROW. IF EXCESSIVE LARGE COBBLES OR BOULDERS ARE ENCOUNTERED IN ANY PART OF THE EXCAVATION, OVER EXCVATE AND BACKFILL WITH SAND OR SUITABLE SCREENED NATIVE 500.5. DISTRIBUTION BOX LID AT GROUND SURFACE RISER SECTION BAFFLE 4" DISTRIBUTION GRAVITY LINE FROM SEPTIC TANK INVERT IN -8" AGREGATE BASE COURSE COMPACTED SUBGRADE DISTRIBUTION BOX DETAIL CROWN FiELD TRENCH TO DIVERT SURFACE WATER 4" PVC INLET PORT IN END CAP 3' MIN 6' MIN —011 EVEGATA I ION TOPSOIL LAVE' LEACHING CHAMBER 12"-36" UNDISTURBED EARTH SAM)TY SILT LOAivi SOIL. CHAMBER TRENCH CROSS SECTION DETAIL GENERAL NOTES: 1. THE OWTS AS SHOWN ON THE PLAN AND THE DETAILS WERE DESIGNED BYSOPRIS ENGINEERING. 2, THE PROPOSED LOT CONDITIONS BY SOPRiS ENGINEERING AND OWNERS. 3. THE EXi51TNG LOT CONDITIONS PER COUNTY GIS DATA BASE, AERIAL MAPPING, LIDAR TOPOGRAPHY AND SURVEY INFORMATION BY PEAK LAND SURVEYING LLC 4. PRIMARY OWNER NAME & ADDRESS: JAMES Peit KELLY JONAS CLEAVER 3724 COUNTY' RD 115 GLENWOOD SPR1 GS, CO 81601 5. LEGAL SUMMARY: A TRACT IN LOT/SEC 20, LOTS 3 & 8, SECTION 29 T65 R88W 6TH PM 6. SITE ADDRESS: 3724 COUNTY RD 115, GLENWOOD SPRINGS, CO 81601 7. PARCEL NUMBER: 2187-292-00-077 8. NEW GARFIELD COUNTY OWTS PERMIT #:SEPT-210-20-6528 9. PREVIOUS CURRENT OWTS PERMIT NUMBERS 1094 & 1852 ISSUED 1981 & 1990 10. CONTRACTOR: GREAT LAKES CONSTRUCTION G:j2020\30169\CIVIL\CIVIL DWGS\DEPLAN.DWG - Feb 02, 2021 - 1:57pm w i 1- z DESIGNED BY - m 11 I CHECKED BY U J J z LJJ LJJ z z W cc 0 /0 ( ) 7 CIVIL CONSULTANTS 502 MAIN STREET ro 0 0 w J Z m CY 0 w 1- d m REVISION 0) r O N 0 GARFIEL❑ COUNTY. COLORADO ONSITE WASTEWATER TREATMENT SYSTEM PLAN AS -CONSTRUCTED OWTS PLAN RECORD DRAWING DATE: 02 - 002 - 2021 JOB NO. 30169.01 SHEET C-1