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HomeMy WebLinkAboutOWTS Design 09.11.2021129 Cains Lane Carbondale, CO 81623 970.309.5259 carla.ostberg@gmail.com September 11, 2021 Project No. C1617 Dave DuMais Dave@dumaismail.com Subsurface Investigation and Onsite Wastewater Treatment System Design 3-Bedroom Residence + 1-Bedroom Future Accessory Dwelling Unit (ADU) 3004 CR 127 Garfield County, Colorado Dave, CBO Inc. performed a subsurface investigation and completed an onsite wastewater treatment system (OWTS) design for the subject property. The 20-acre property is located outside of Glenwood Springs, in an area where OWTSs and wells are necessary. Legal Description: Section: 29 Township: 6 Range: 89 W1/2NWSE Parcel ID: 2185-294-00-021 SITE CONDITIONS A 3-bedroom, single-family residence presently exists and is utilizing an existing OWTS. The OWTS consists of a 1000-gallon, two-compartment concrete septic tank followed by a seepage pit. Garfield County Individual Sewage Disposal System (ISDS) Permit 2454 documents the system. The permit received final approval September 8, 1985. A letter from Zamora Excavating, Inc. dated November 9, 2020 (enclosed) documents the system is in poor condition and in need of replacement. The proposed replacement OWTS will serve the existing 3- bedroom residence and a future 1-bedroom Accessory Dwelling Unit (ADU) which will be located in a proposed detached garage. The residence is currently served, and will continue to be served, by a private well located over 400-feet north of the residence, near driveway entrance off CR 127. No proposed OWTS component will come within 25-feet of any water line The proposed soil treatment area (STA) location has an approximate 25-28 percent slope to the east. The area is vegetated with scrub oak and native grasses. Clearing of vegetation in the proposed area will be necessary. We recommend separating the proposed STA beds to maintain the mature vegetation between the beds for stability of the hillside. There should be no traffic or staging of material over the future STA site to avoid compaction of soils prior to construction of the STA. Page 2 Approx. septic tank location View of approx. tank location and seepage pit Seepage pit Several feet of water in seepage pit Proposed STA Page 3 SUBSURFACE The subsurface was investigated on May 6, 2021 by digging one soil profile test pit excavation (Test Pit). Only one Test Pit was excavated due to challenging terrain and dense vegetation limiting equipment access in the area of the proposed STA. A visual and tactile soil analysis was completed by Carla Ostberg at the time of excavation.1 The materials encountered in Test Pit #1 consisted of moist, dark brown organic topsoil to 1.5-feet, underlain by medium brown, moist, clay loam to a maximum depth explored of 7.0-feet. No bedrock or groundwater was encountered. A sample of the soils was taken from Test Pit #1 at 3-feet below grade. The soil formed a ball and a ribbon 1 to 2-inches in length before breaking. Soil structure shape was blocky and consistence was friable to firm. Soil texture was both gritty and smooth. STA sizing is based on Soil Type 3, Clay Loam with moderate structure grade. The proposed design will consist of pressure dosed, over-excavated, unlined sand filters with a minimum of 2-feet of sand filter material allowing sizing based on Treatment Level 3 (TL3). A long term acceptance rate (LTAR) of 0.65 gallons per square foot will be used to design the OWTS. Test Pit #1 Backfill 1 Carla Ostberg holds a Certificate of Attendance and Examination from the CPOW Visual and Tactile Evaluation of Soils Training. Page 4 Sieved sample Ribbon length DESIGN SPECIFICATIONS The existing OWTS components will be properly abandoned by pumping and crushing the concrete structures and either removing or filling the void with onsite soils. Design Calculations: Average Design Flow = 75 GPD x 2 people/bedroom x 4 Bedrooms = 600 GPD LTAR = 0.65 GPD/SF 600 GPD / 0.65 GPD/SF = 923 SF The new OWTS design is based on 3-bedrooms in the existing residence and a proposed 1-Bedroom ADU over a detached garage. An average daily wastewater flow of 600 GPD will be used. Page 5 For the purposes of this OWTS design, Benchmark Elevation has been established as the existing sewer line exiting the residence as 100’. CBO Inc. should be notified of any discrepancies or problems with grade elevations of proposed components during installation of the OWTS. OWTS Component Minimum Elevation Primary Tank Inlet Invert Approximate horizontal distance 12’ / min. 2% fall / min. 3” fall Automatic Distributing Valve (ADV) Approximate horizontal distance 86’/ min. 1% rise for drain back / min.10.75” rise Infiltrative Surface Approximate horizontal distance to furthest bed 50’ / min. 1% fall / min. 6.25” fall *Elevations are based upon standard OWTS installation practices. Component elevations may change during installation due to site conditions. The sewer line exiting the residence must be replaced with minimum 4-inch diameter, SDR-35 sewer line and have a double-sweep clean out and a minimum 2% grade to the septic tank. The sewer line existing the ADU must also be a minimum 4-inch diameter, SDR-35 sewer line and have a double-sweep clean out and a minimum 2% grade to the septic tank. This sewer line may be placed in the same trench as the proposed pump line to the ADV. The system installation will include a 1500-gallon, two-compartment Infiltrator® poly septic tank followed by an Infiltrator® poly single-compartment poly pump chamber with an Orenco® Biotube Pump Vault and an Orenco® PF3005 pump. The floats should be set to dose approximately 80 gallons each pump cycle, allowing approximately 9 gallons of drain back after each pump cycle. A pump curve is enclosed. The control panel for the pump must be located within line of sight of the septic tank. We recommend Valley Precast out of Buena Vista be contracted for start-up of the pumping system. Pump Table Dose Range Max = 159 gal. (600 GPD x 25% + 9 drain back) Min. 89 gal. (20 gal x 4) + 9 gal drain back Dose Setting 80 gallons/dose 9 gallons drain back (86’ / 1.5” diameter pump line) Float Separation 500-gallon single-compartment Infiltrator® poly pump chamber 6” on/off float separation Pump Criteria 30.5 gallons per minute (GPM) 37.9 feet total dynamic head (TDH) Effluent will be pumped through a 1.5-inch diameter pump line from the pump chamber to an Orenco® automatic distributing valve (ADV), model 6402. This pump line must have a minimum 1% grade for proper drain back into the tank after each pump cycle. The ADV must be placed at a high point in the system in an insulated riser with access from grade. Screened rock must be placed below the ADV to support the ADV and to assure the clear pipes exiting the ADV remain visible for future inspection and maintenance. Effluent will be pressure dosed to through 1.5-inch diameter distribution lines to two 10’ x 46.5’ beds. A minimum of 2-feet of sand filter material will be installed in the over-excavated footprint. Sand filter material must be clean, coarse sand, all passing a screen having four meshes to the inch. The sand must have an effective size between 0.15 and 0.60 mm. The uniformity coefficient must be 7.0 or less. Material meeting ASTM 33, for concrete sand, with three percent or less fines passing 200 mesh sieve may be used. A gradation of the sand media must be submitted to this office prior to obtaining the sand. Laterals must be 1.5-inches in diameter with 5/32-inch diameter orifices facing down, spaced 3-feet on center, installed on the center of each GeoMat™ with the filter fabric over the laterals. Three 39” wide GeoMat™ sheets must be placed on each 10-foot wide beds. All material associated with the GeoMat™ Page 6 installation must be proprietary products associated with the GeoMat™, including orifice shields and geotextile fabric. Manufacturer instructions must be followed regarding installation of the GeoMat™. Each 1.5-inch diameter lateral must end in a sweeping ell facing up with a ball valve for flushing. Valves should be placed in a 10-inch sprinkler box for access. Laterals must be covered by a soil separation fabric and at least 1-foot of topsoil or other suitable soil able to support vegetative growth. There shall be no cobble-sized (<2.5”) or greater rock in final cover over the GeoMat™. Inspection ports must be placed at each corner of each bed. Ports may be cut to grade and covered with a valve box for access. COMPONENT SPECIFICATIONS The component manufacturers are typical of applications used by contractors and engineers in this area. CBO Inc. must approve alternative components prior to installation of the OWTS. Requests must be submitted, in writing, to our office for approval prior to installation. Component technical data sheets are available upon request. COMPONENT MANUFACTURER MODEL NO. COMMENTS Septic Tank Infiltrator® IM-1530-2CP 1500-gallon, two- compartment poly septic tank Pump Chamber Infiltrator® IM-540-HH 500-gallon, poly pump chamber Risers and Lids Orenco® Risers and Lids Pump Orenco® PF300511 ½ HP 120 Volt Biotube ProPak Pump Package Orenco® BPP30DD Vault, Filter, Control Panel (demand dose) Tank Risers and Lids Orenco® Double-walled PVC Risers and Lids (24” diameter) ADV Orenco® V6402A 1.5” Inlet and Outlets ADV Riser and Lid Orenco® Double-walled PVC Risers and Lids (30” diameter) GeoMat™ GeoMatrix Systems, LLC 140’ GeoMat™ (39” sheets) 90 orifice shields Flushing Assembly Orenco® 1.5” diameter (2) 45° or 90° long sweep only (6 total) Construction must be according to Garfield County On-Site Wastewater Treatment System Regulations, the OWTS Permit provided by Garfield County Building Department, and this design. INSTALLATION CONTRACTOR CBO Inc. expects that the installer be experienced and qualified to perform the scope of work outlined in this design. The installer must review this design thoroughly and coordinate with our office in advance of installation. Any additional conditions in this design or county permit must be completed and documented prior to final approval of the OWTS installation. Communication between the installer and this office is expected throughout the installation. Page 7 INSTALLATION OBSERVATIONS CBO Inc. must view the OWTS during construction. The OWTS observation should be performed before backfill, after placement of OWTS components. Septic tanks, distribution devices, pumps, dosing siphons, and other plumbing, as applicable, must also be observed. CBO Inc. should be notified 48 hours in advance to observe the installation. In an effort to improve the accuracy of the record drawing, we request that the installer provide a sketch of the installation, including path of the sewer lines, water line installation (if applicable), septic tank location, STA location, and measurements from building corners or another fixed objects on the property. This sketch is most easily provided on Sheet W2.0 of the OWTS Design Packet. Photographs of the installation and final cover are also requested to supplement our installation documentation. REVEGETATION REQUIREMENTS An adequate layer of good quality topsoil capable of supporting revegetation shall be placed over the entire disturbed area of the OWTS installation. A mixture of native grass seed that has good soil stabilizing characteristics (but without taproots), provides a maximum transpiration rate, and competes well with successional species. No trees or shrubs, or any vegetation requiring regular irrigation shall be placed over the STA. Until vegetation is reestablished, erosion and sediment control measures shall be implemented and maintained on site. The owner of the OWTS shall be responsible for maintaining proper vegetation cover. OPERATION INFORMATION AND MAINTENANCE The property owner shall be responsible for the operation and maintenance of each OWTS servicing the property. The property owner is responsible for maintaining service contracts for manufactured units, alternating STAs, and any other components needing maintenance. Geo-fabrics or plastics should not be used over the STA. No heavy equipment, machinery, or materials should be placed on the backfilled STA. Machines with tracks (not wheels) should be used during construction of the STA for better weight distribution. Livestock should not graze on the STA. Plumbing fixtures should be checked to ensure that no additional water is being discharged to OWTS. For example, a running toilet or leaky faucet can discharge hundreds of gallons of water a day and harm a STA. If an effluent filter or screen has been installed in the OWTS, we recommend this filter or screen be cleaned annually, or as needed. If the OWTS consists of a pressurized pump system, we recommend the laterals be flushed annually, or as needed. The homeowner should pump the septic tank every two years, or as needed gauged by measurement of solids in the tank. Garbage disposal use should be minimized, and non-biodegradable materials should not be placed into the OWTS. Grease should not be placed in household drains. Loading from a water softener should not be discharged into the OWTS. No hazardous wastes should be directed into the OWTS. Mechanical room drains should not discharge into the OWTS. The OWTS is engineered for domestic waste only. Page 8 10-26-2021 ADDITIONAL CONSTRUCTION NOTES If design includes a pump, weep holes must be installed to allow pump lines to drain to minimize risk of freezing. The pump shall have an audible and visual alarm notification in the event of excessively high- water conditions and shall be connected to a control breaker separate from the high-water alarm breaker and from any other control system circuits. The pump system shall have a switch so the pump can be manually operated. Excavation equipment must not drive in the excavation of the STA due to the potential to compact soil. Extensions should be placed on all septic tank components to allow access to them from existing grade. Backfill over the STA must be uniform and granular with no material greater than minus 3-inch. LIMITS: The design is based on information submitted. If soil conditions encountered are different from conditions described in report, CBO Inc. should be notified. All OWTS construction must be according to the county regulations. Requirements not specified in this report must follow applicable county regulations. The contractor should have documented and demonstrated knowledge of the requirements and regulations of the county in which they are working. Licensing of Systems Contractors may be required by county regulation. Please call with questions. Sincerely, CBO Inc. Reviewed By: Carla Ostberg, MPH, REHS Romeo A. Baylosis, PE Pump Selection for a Pressurized System - Single Family Residence Project Parameters Discharge Assembly Size Transport Length Before Valve Transport Pipe Class Transport Line Size Distributing Valve Model Transport Length After Valve Transport Pipe Class Transport Pipe Size Max Elevation Lift Manifold Length Manifold Pipe Class Manifold Pipe Size Number of Laterals per Cell Lateral Length Lateral Pipe Class Lateral Pipe Size Orifice Size Orifice Spacing Residual Head Flow Meter 'Add-on' Friction Losses 1.25 86 40 1.50 6402 50 40 1.50 15 6 40 1.50 6 44.5 40 1.50 5/32 3 5 None 0 inches feet inches feet inches feet feet inches feet inches inches feet feet inches feet Calculations Minimum Flow Rate per Orifice Number of Orifices per Zone Total Flow Rate per Zone Number of Laterals per Zone % Flow Differential 1st/Last Orifice Transport Velocity Before Valve Transport Velocity After Valve 0.68 45 30.5 3 1.0 4.8 4.8 gpm gpm % fps fps Frictional Head Losses Loss through Discharge Loss in Transport Before Valve Loss through Valve Loss in Transport after Valve Loss in Manifold Loss in Laterals Loss through Flowmeter 'Add-on' Friction Losses 6.5 4.6 7.1 2.7 0.1 0.1 0.0 0.0 feet feet feet feet feet feet feet feet Pipe Volumes Vol of Transport Line Before Valve Vol of Transport Line After Valve Vol of Manifold Vol of Laterals per Zone Total Vol Before Valve Total Vol After Valve 9.1 5.3 0.6 14.1 9.1 20.0 gals gals gals gals gals gals 30.5 41.2 gpm feet 0 5 10 15 20 25 30 35 40 0 50 100 150 200 250 300 Net Discharge (gpm) PumpData PF3005 High Head Effluent Pump 30 GPM, 1/2HP 115/230V 1Ø 60Hz, 200V 3Ø 60Hz PF3007 High Head Effluent Pump 30 GPM, 3/4HP 230V 1Ø 60Hz, 200/460V 3Ø 60Hz PF3010 High Head Effluent Pump 30 GPM, 1HP 230V 1Ø 60Hz, 200/460V 3Ø 60Hz PF3015 High Head Effluent Pump 30 GPM, 1-1/2HP 230V 1Ø 60Hz, 200/230/460V 3Ø 60Hz Legend System Curve: Pump Curve: Pump Optimal Range: Operating Point: Design Point: 3004 CR 127 Legend 100 ft N➤➤N ler 1 • GARFIELD COUNTY BUILDING AND SANITATION DEPARTMENT Permit N _2 4 5 a t..109 8th Street Suite 303 Assessor's Parcel No.i Glenwood Springs, Colorado 81601 Phone (303) 945 -8212 This does not constitute to k INDIVIDUAL SEWAGE DISPOSAL PERMIT a building or use permit. t t PROPERTY pipt3 Owner's Name William M Park Present Address 1962 132Rd. Glenwood Phone 945 -8766 1 System Location 004/ County Road 127, Glenwood Springs 1 6 1 Legal Description of Assessor's Parcel No.i 6 SYSTEM DESIGN b q 11 i1›Septic LTank Capacity (gallon) Other A_ir___iy 9 i iyPRate (minutes /inch) of Bedrooms (or other)I S. Required Absorption Area - See Attached i L"V 21 2 ox ;• ( /( 1 J) lc)II7- /-/4 y c 2 . 4^ Ey { R' X / fr X 1_2 t.- - )- 7 Special Setback Requirements:1 ! f Date Q S.- 8 Inspector z‹4 I FINAL SYSTEM INSP &CtION AND APPROVAL (as install- 'r"; C.;..1- Call for Inspection (24 hours notice) Before Covering Installation Pi, System Installer_ aJ. in. Peal&4' Septic Tank Capacity 00 0 Septic Tank Manufacturer or Trade Name 7- C U. T A /r,l Septic Tank Access within 8" of surface ei-S i c vAbsorptionArea13 ' )(I$ ) /v Q i i :, Absorption Area Type and /or Manufacturer or Trade Name i • Adequate compliance with County and State regulations /requirements 44S 4 Other b t Date V 4 'Inspector 4-1../1.. _,- RETAIN WITH RECEIPT RECORDS AT CO STRUCTION SITE A f CONDITIONS: 1. All installation must comply with all requirements of theColorado State Board of Health Individual Sewage Disposal Systems Chapter tilt i 25, Article 10 C.R.S. 1973, Revised 1984. 2. This permit is valid only for connection to structures which have fully complied with County zoning and building requirements. Con- i iiinectiontoorusewithanydwellingorstructuresnotapprovedbytheBuildingandZoningofficeshallautomaticallybeaviolationora requirement of the permit and cause for both legal action and revocation of the permit.t, 3. Any person who constructs, alters, or installs an individual sewage disposal system in a manner which involves a knowing and materi h }al variation from the terms or specifications contained in the application of permit commits a Class I. Petty Offense ($500.00 fine —6 tl'.` it months in jail Or both). 1 Applicant: Green Copy Department: Pink Copy h t . sd 1 . JNDIVIDUAI. SEWAGE SEWAGE DISPOSADISPOSAL SYSTEM APPi.ICATION OWNER ADDRESS IQ(o•2 -W Gan,,,Arookzeia Coo PHONE c t`45 531 bb Nn 614S (C' S Pates er. CONTRACTOR t w L- . ADDRESS On 2 — (COO tea Sp t^1 PHONE c45 5300 PERMIT REQUEST FOR 44 NEW INSTALLATION ALTERATION ( ) REPAIR Attach separate sheets or report showing entire area with respect to surrounding areas, topography of area, habitable building, location of potable water wells, soil percolation test holes, soil profiles in test holes See page 4). J.00ATION OF PROPOSED FACILITY:COUNTY Coq„ Q jo2a ` Near what City or Town 0,1/40o,•„ ,.ree. - Q GpIrtel or Lot Legal Description Tov.ma.: ( Soak.Ra..tiie.' S Wes#. ntekke. k"' PGGethto1, a4 wesk ya kke,ekku2es* Yq Qpini WASTES TYPE: 04 Dwelling Transient Use Commercial or Industrial Non - domestic Wastes Other - Describe BUILDING OR SERVICE TYPE: Number of bedrooms: 3 Number of persons a) Garbage Grinder x) Automatic Washer 4 Dishwasher SOURCE AND TYPE OF WATER SI 'PM .Y: QQ WELL SPRING () STREAM OR CREEK Give depth of all wells within 180 feet of system: %\wnL. If supplied by communtiy water, give name of supplier: GROIJND CONDITIONS: Depth to bedrock: Depth to first Ground Water Table: Percent Ground Slope: DISTANCE TO NEAREST COMMUNITY SEWER SYSTEM: flares) Was an effort made to connect to community system? f® TYPE OF INDIVIDUAL SEWAGE DISPOSAL SYSTEM PROPOSED: Qd Septic Tank Aeration Plant Vault Vault Privy Composting Toilet Recycling, potable use Pit Privy Incineration Toilet Recycling, other use Chemical Toilet ( ) Other - Describe: FINAL DISPOSAL BY: QQ Absorption Trench, Bed or Pit Evapotranspiration Underground Dispersal Sand Filter Above Ground Dispersal Wastewater Pond Other - Describe: WILL EFFLUENT BE DISCHARGED DIRECTLY INTO WATERS OF THE STATE? '00 PERCOLATION TEST RESULTS: (To be completed by Registered Professional Engineer) Minutes per inch in hole No. 1 Minutes per inch in Hole No. 3 Minutes per inch in hole No. 2 Minutes per inch in Hole No. _ Name, address and telephone of RPE who made soil absorption tests: Name, address and telephone of RPE responsible for design of the system: Applicant acknowledges that the completeness of the appliction is conditional upon such further mandatoryd and additional tests and reports as may be required by the local health department to be made and fa d the by the applicant or by the local health department for purposes of the evaluation of the application;issuance of the permit is subject to such terms and conditions as deemed necessary to inusre compliance with rules and regula adopted ts make, information Oand reports submittedbmi 1973, ed hereith and required to be submitted certifies that all snbytheapplicantareorwill be represented to be true and correct to the best of my knowledge and belief andaredesignedtobrereliedonbythelocaldepartmentofhealthinevluatingthesamefropurposesofissuing the permit of the a fpr ca t io n. I n or revocation of any understand perm t granted falsification based upon said applicationand in legal the denial of the applicaio revca action for perjury as provided by law. Signed AM--c ille Date S tS S L 't•' t 13 a0 TA k v II, kg_ c,_ 0 4c, N gas,,,,, r --.f " sw s 3X co . e4w.0 eQ. PERCOLATION TEST RESIITTS: (To be completed by Registered Professional Engineer)1 Minutes per inch in hole No. 1 Minutes per inch in Hole No. 3 Minutes per inch in hole No. 2 Minutes per inch in Hole No. _ Name, address and telephone of RPE who made soil absorption tests: Name, address and telephone of RPE responsible for design of the system: Applicant acknowledges that the completeness of the appliction is conditional upon such further mandatory and additional tests and reports as may be required by the local health department to be made and furnished by the applicant or by the local health department for purposes of the evaluation of the application; and the issuance of the permit is subject to such terms and conditions as deemed necessary to inusre compliance with rules and regulations adopted under Article 10, Title 25, C.R.S. 1973, as amended. The undersigned hereby certifies that all statements make, information and reports submitted herewith and required to be submitted by the applicant are or will be represented to be true and correct to the best of my knowledge and belief and are designed to bre relied on by the local department of health in evluating the same fro purposes of issuing the permit applied for herein. I further understand that any falsification or misrepresentation may result in the denial of the application or revocation of any permit granted based upon said application and in legal action for perjury as provided by law. Signed Cas/Q.kavv. N cR Date S I «1 in EASE DRAW AN ACCT IRATE MAP TO YOUR PROPERTY 13 RCS TA sekV j Qet pa SQy,.,an T L.ec._ e-`c'Cl 1,04 -52. d 6er4- c T.rN.__ a i swws. ccA. rQc. w. 0 tor- \vewGa w pi.lT PI AN AND DESIGN FRATI IR ES Include by measured distance location of wells, springs, potable water supply lines, cisterns, buildings, property lines, subsoil drains, lake, water course, stream, dry gulch and show location of proposed system by direction and distance from dwelling or other fixed reference object, and additional submissions in support of this application such as data, plans, specifications statements and commitments. CRS Via,; ,,v, ,k at w 00-113::1/40,3 0 iscidD,cibser til/+ceake 08 0- attr kJU,vu Juksitaa cortzczjecalops„ C see CX.aastri broc) - e ISa© ea..nC kerizmi 1. Ob' Jrrocer}i i... nt. To lea,Gle n " r,AA re"0 4l P° 1 'sj Ps\S 0 t-zc w ewal Garfield County, CO Developed by Account Number R080175 Par cel Number 218529400021 Acr es 20 Land SqFt 0 T ax Ar ea 131 2019 Mill Levy 75.6980 Physical Addr ess 3004 127 C OUNTY RD GLENWOO D SPRINGS 81601 O w ner Addr ess PARK, WILL IAM M PO BO X 154 GLENWOO D SPRINGS C O 81602- 0154 2019 T otal Actual Value $388,730 Last 2 Sales Date Pr ice 11/13/2001 $114,500 1/7/2000 $0 Date created: 10/21/2020 Last Data Uploa ded: 10/21/2020 2:08:05 AM 921 ft Overvi ew Legend Parcels Roa ds Parcel/Account Number s Highw ays Limited Access Highwa y Major Road Loca l Roa d Minor Road Other Road Ra mp Ferry Pedestria n Way Owner Na me Lakes & River s County Boundar y Line