HomeMy WebLinkAboutOWTS ReportIITOUNTËTIN CROSS
ENGINEERING. INC.
Civil alld ãnvåRçnnnental Gonsulting Ënd Ѐslgn
January 27"2ü21
Micha *l Fr¡ ller .A.rchif ecf s
CIO Ms" Kelleigh Condsn
23400 Two Rivers Road, Suite 4l
Basalt, Cû 81621
RE:And*rsç¡¡ Resiclenceo 278 -Rnnee Lane, Garlield Counfy, C0 * OWTS R.eport
Dear Kelleigh:
The pu:pose of this oorresponde¡ce is to infcrm you about the onsi-te w¿stewaTer treatment system
(û\Ã/TS) designed fsr the reconstrucfion projeet of the Anderson Residence. The project p{rposes
to raze and ccnsiruof a new rcsidence. The project is located in Garfield County, just to the west
r:f the Hagle County line near Carbondale, CO at 278 Ronee l-ane. The main floor of the residence
will be a gravity system to a convenÌicnnl septie rank where a pump will pressur:e close to a,leach
lield comprised of a bed of infìlfration chsmbers. The plwnbing of the lower level will need a
selver ejector pump to lift into the gravity system. The residence will be seryecl by an existing
well. The OWTS is not witliin a 100-year flood plain boundary. There are practical ccnstraints
that you should be â\e'åre of when consiclering the proper design, construction, and opei:âtic)ti,
Sr¡hsurface
The soil was determined to be R2A sails with an LT,4R value approximated as û.5t gallons per
day per square fbot (GPII/sq.ft.) from soil evaluations performed by C'lL Thompson. A plofils
hole was excavated and an inspection revealed that no bedrcclc ol high groundwate¡"tabJe is within
an 8' dep{h of the leaching area.
Desien Calculatiogs
ll-he residcnce is propospd to be 4 bedrocms with a 1 bedroom caretaker unit absve the gzu'age"
IJsing Garfield County Table 6-1 far a S-bedloom rcsideRce, this yields 60ûgatlons per day (GPD)
total. "Ihe design calculations for sizing cf the septic system and the leach ficld f'nllow:
. ¡Lnderson Residence: 5 bedrooms: 600 GPD
. Based on soil cvaluation and percolation tests results, LTAR: 0.50 GPDlsq.ft.. Minimum absorplion area = 60ü GPD 10.50: 1.200 sq. ft.
ç Reductions in soil treaünenf areas for bed treâ*nent with pressure dosing
= 1,2A0 sq. lt. * {).7 * 1.0 = 840 sq.ft leach area
r Required chambers: (840 sq.ft)l(12.34 sq.ftlchamber): 68 chambers, Use four rows of I7 chambers, 68 chambs's
r Requircd septic lank volums = 1,500 gallons per: Garfield County Tabte 9-l. Dasing frec¡uency:4 dosesperday; dosç volume:600 GPÐ i 4 dcses: tr5ügal.ldose* Prunp(s) shotrld provide 70 gprn at 25' of Total Dynamic ï{ead
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Ânsderson Residence
January,202'l
Page 2 nf3
¡ PVC later¿l distributío¡ pipes'should be Schedule 4t, I-1/2" in diametêr.
o FVC suppty and manifold pipes slr*nld be Schedule 40, 2" in diameter.
r Eaeh lateral pipe should have seventeen t/a" åiqrneter holss drilled in the lal.eral at 5'
spacing withtire first hole located at2.5'fiom the sta¡t of the bed.
The eomponents maüufacturers are typical f-or the area. .Altølativas may be considered by
contacting this office. Conshuction must be in açccrda¡ce with the specifications of Garfield
County Envimnmental Health, the O\VTS pennit, and this design.
Topsoil should be placed or¡er the OWTS and planted with native grasses. No lalge vrgetalion
and/or plants with tapr'oots should be planæd over fhe absorption area nor grasses that require
excessive irrigation.
Setbåckq
The location fur the septic and dosing tanks are limited by setbaclc requirements per Garfield
Coung and thc State of üolorada. Tlresç include:
. 50'FRCIM \ryELL
r I0'FROM $/ATËR SUPPLY LINE
l , 5' FROM BUILÐIÌ{G 14,'ITH BASEMEN?
r 10' FROM PROPERTY LINE
r 10' F*ûM LINED POND, DITCH, ûR STRE.4M
. 5{)' FROM W,ATER BOÐY
c 10' FROM CREST OF BANK
r 5'F"RûM LEACH FIELI)
The leach field setbaclc requirements arer
r 10û'FRÛM liVELL,
. 25'FROM 1MATER SUPPLI'LINE
¡ 2ü' FROM BUILÐINC WITI{ BASEMEN'Ï
o 1û' FROM FR0FtrRTY LINE
r l0' FROM LIhIED POND, DITCH, OR STRËAM
. 5û' FROM Tï/ATER EODY
o 25'FROM CREST OF BANK
s 5'FR0M SEFTIC TANK
The setback requirements deal primârily with br¡ildings and po-tenTial contamination from the
septic tank, dasing tank, and leach field to either culinary water or surface'water. These setbacks
have been included on the plans for- refçrelrce,
Thele is an existing pond that is lined and must remain lined to cc¡nfr¡rm ta the required setbarks"
The leach field wjli need to he located out of the required serbaclc distance from the top of bank.
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Ansrierson Residence
January,202l
Page 3 of3
ûneration lnfarxnatiøn and Mainte¡¡&nre
The Owner will neerl to be respcnsi,ble fur dre operation and management of the OWTS. Geo,
fabrics or plastics should not be used over the absorplion area. No heavy equipment, palking of
lrachinety, cr n:.aterials should be placecl on tl¡e absorption area. Livcslock shoulil not gruze on
the abscrption area. Plumbing fixtr¡res should be checked to ensure that no additional r¡oater is
being discharged to OS/TS; Ibr example, running toilefs or leaky faucets can discharge hundre.ds
of gnllons of water a day and harm the absorption ar:ea.
Garbage disposal use should be mjnimized, ¿nd non-biodegradable materials should not be placed
into the û\üTS. Crease should not be placed in drains and grease traps shoulcl be installed
upstr:eam of the eeptic lank but downstrcam fiam any l<itchen. Loading fiom a water softener
should not be discharged into the OWTS. No hazardous wastes shoulci he directed into the OV/TS.
The O1{¡TS is engineered for don'restic waste onl,v.
1'he {Jv,ner will }ike}y need to contract witir a septic system cl*aner to clean the septic tanl< every
two years. or as needcd gauged by measuremenT of solids in the tank. The standards cf
perfornance for thc septic systen: cleaner are recnmrïended tc he the fallnrving, at a minimum:
l. The Systems Cleaner shall be licenqed.
2. The Systems Cleaner', when cieaning a septic tank, shall rßmovethe liquid. sludge, and
scrlnr, Ieaving no more than three (3) inches depth of sewage in a seplic tank.
3. The Systems Cleanel shall maintair his equipment so as 1o çnsure that no spillage of
s€wage wíI1 occur durirrg transportation, and that its employees are not subject to undue
health hazards.
4. The Syslems Cleaner shall dispose o1'the collected selvage only at a designated site
rccogrúzed by the Board of I'{ealth,
Çonstruet'ion Obserr.ratår n
Prior to being backfilled, the construction of the OWTS and all of the components wjll necd to be
observed by representatives o{'Mountain Cross Engineering, lnc.
The conclusions and opinicns that are expressed above are t¡ased on the infom"¡ation avaiiabie a{
The time of preparation of this repofi. Any additional information presented aflerward marv recluire
that these opinions and the design be m*dified.
Thank yau for the opportunity tc provide this report. Føel fi'ee ta call if you have any questions,
concerns, or oomillents.
C'ro.rs
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