HomeMy WebLinkAboutEngineer's OWTS Design PlanCIVÏL ENGINEERING WATER RESOURCES ENGINEERING ENVIRONMENTAL CONSUTTING
July 28, 2023
Garfield County Community
Development Department
Public/Environmental Health
108 8th Street, Suite 401
Glenwood Springs, CO 81601
RE: 6800 CR 252 Rifle, CO Parcel 192120300033 - Design Report for Proposed On-Site
Wastewater Treatment System.
Dear GCCDD
On behalf of the owner, Ruben Jenson, herein included are this design report, permit drawings
and a Garfield County OWTS Permit Application. As indicated in the application, the individual sewage
disposal system will treat and dispose of domestic waste from a planned 3-bedroom dwelling.
The septic system as designed will include a 4-inch sewer, effluent and drainfield distribution
pipes, 1,O0O-gallon septic tank, and approximately 192 feet of drainfield infiltrator chambers. The
drainfield will be located west and downhill of the house. The nearest surface water, West Rifle Creek,
is located over 400 feet away from the drainfield. The terrain in the vicinity of the OWTS is approximately
ten percent and well vegetated with native grasses and forbs. The primary offset distance that needs
to be considered is the distance to the county road R/OA// which is noted by a fence. The fence, terrain
and other features were surveyed with survey-grade GPS. Areal imaging was also collected to help
locate the system in relation to the site.
Preliminary lnvestigation
A detailed soil investigation for the proposed drainfield location was conducted July 18,2023 by
me. Two soil profile pits (SPP), were excavated near the anticipated drainfield location. The soil
encountered within the SPPs was evaluated visually and tactilely based on texture, structure and the
ribbon test as required for the septic system in accordance with CDPHE/WQCC, Regulation #43
Section 43.5.D.2. No signs of groundwater or restrictive layers were encountered in the SPPs. The
soils in the vicinity of the drainfield are predominately fine-grain sand to silty loam. A scaled soil log is
provided on sheet 4 of design drawings.
Design
Based on the results of the soil classification, the drainfield was sized using the methods outlined
in CDPHE/WQCC, Regulation #43. The design calculations are presented in attachment A of this
report. The drainfield shall be installed in accordance with applicable sections of Regulation #43,local
codes and manufactures' recommendations. All sewer pipe shall be SCH 40 or SDR 35, though SCH
40 is preferred and is required under roads and/or parking areas. All pipe shall be placed to drain and
bedded with native sandy backfill or road base under driveways and/or parking areas. Steel mesh can
be placed under the drainfield chambers to prevent rodents from burrowing into the void space under
the drainfield chambers, but this will be at the owner's choice. The drainfield chambers shall be Quick4,
manufactured by lnfiltrator Water Technologies, or equal. The septic tank shall be 1,O0O-gallon poly
tank manufactured by lnfiltrator Water Technologies or equal. The plan set details how the drainfield
shall be constructed and quantities and specifications for the system products are included on sheet 4
of the plan set.
PO BOX 1293 CRAIG, CO 81626 PHONE (970) 620'4030
July 28, 2423
Page 2 of 4
encl: as noted
///r/ / ?----
Please let me know if you have any questions of comments
Best Regards,
Will A. Myers, P.E
Attachment A
Design Calculations
Ruben Jenson
6800 cR252 RIFLE 81650
Sources/Notes:
Allsources of information and design requirements are CDPHE/WQCC, Regulation #43
l. Design Flow Rate
Desiqn Component Notes/l nformation Sou rce
3-Bedroom House
No. of Bedrooms 3
Occupants based on Bedrooms:6 Table 6.1
Wastewater Flow per Occupant:75 qpd Table 6.1
Daily Design Flow Rate 450 qpd
ll. Septic Tank Design
Design Component Notes/l nformation Sou rce
3-Bedroom House
No. of Bedrooms 3
Min. Septic Tank Capacity Based on
Bedrooms:1,000 gal Table 9.'1
sal
Ruben Jenson
6800 cR 252 RTFLE 81650
lll. Drainfield Design
Des qn Component Notes/lnformation Source
Peak dailv desiqn flow rate 450 spd
Soil texture within/near drainfield Sandv Loam
Soil Tvpe 2 Table '10-1
Treatment Level 1 Table 10-1
Long-Term Acceptance Rate (LTAR)1 0.6 qal/dav/sq ft Table 10-1
Required drainfield absorption area 750 sq ft
Adiustment factor for chambers:0.7 Table 10-3
Adjusted d rainfield absorption area:525.0 sq ft
Width of drainfield chamber 3.0 ft Standard Size
Total required lenqth of drainfield 175.0
Lenqth of drainfield chamber:4.0 ft 5 foot also standard
Min. required number of drainfield chambers:44.0O
Number of drainfield chambers in proposed desiqn 48 chambers
Number of zones 1
Number of laterals per zone 4
Number of chambers per lateral 12.00
Lateral length 48 ft
Total lateral lenqth:192 ft
Min. distance between trenches 4 fr Section 43.10.F.1
Min. trench CL spacinq:7 ft
Desiqn trench CL spacinq I ft
Sources/Notes:
All sources of information and design requirements are CDPHE/WQCC, Regulation #43 unless othenivise noted
1 Determined from a field soil evaluation.
Attachment B
Permit Plan Set
PARCEL BOUNDARY
. PROPOSED
3-BEDROOM HOME
PROPOSED l.OOO GAL.
SEPTIC TANK--
?PROPOSED DRA]NFIELDt'^N
NI
+
PROJECT S¡TE
GLENWOOD
SPRINGSt-70
<.l¡
1RIFLE
{1
Scale: '1" = 30 Miles COUNTY OF GARFIELD
STATE OF COLORADO
INDEX OF SHEETS
SHEET NO SHEET TITLE
LOCATION & SITE PLAN
SYSTEM PLAN
PROFILE & DETAILS
CALCULATIONS & NOTES
3
4
LEGAL LOCATION: NESW SECTION 20, T.4S.; 93W., PARCEL 192120300033 l.)
SITE NOTES
1, OWNÊR PLANS TO HAU L WATER RATHER THAN DRILLING A WELL INITIALLY
2. ÏHERE ARE NO WATER FEATURES WTHIN 1OO FEET OF THE PROPOSED OWTS.
GARFIELD COUNTY OWTS DESIGN
LOCATION & SITE PLAN
SITE ADDRESS:
6800 cR 252
RIFLE, CO 81650
SHEET
1oF 4
For:
REUBEN & LISA JENSEN
PO BOX 445
CARLSBAD, TX 76934
By:
Headwater Engineering
P.O. BOX 1293
Craig, CO 81626
.---r---f7-,"-^
H
GRAPHIC SCALE (FEET)
Revised=ile:
Dâte:Checked BY: WAT¡Drawn Byr WAM
GARFIELD COUNTY OWTS DESIGN
SYSTEM PLAN
SITE ADDRESS:SHEET
20F 4
6800 cR 252
RTFLE. CO 81650
0*00
For:
REUBEN & LISA JENSEN
PO BOX 445
CARLSBAD, TX 76934
o
o
By:
Headwater Engineering
P.O. BOX 1293
Craig, CO 81626
Revised:
g+20
0*À0
O+60
o
4'ø EFFLUENT F|PF
6680
I lOO'MIN FROM ANY \,IELL
48'
7*40
48' DRAINFIELD CI.IAMBER
TfP. OF 12 PER LA'IERAL) (48 TÒTAL)
N
7 4" Ø |NSPECT|oN
P|PE CryP. oF 4)
s'(rvìlN.)
4oo
END CAP (l-Ì'P. oF 8)
oo
Date:Checked Bv: WA[4
GRAPHIC SCALE (FEET)
C.l. = I'
SOIL PROFILE PIT
LEGEND
+
File:
Drawn By: WAM
4^ ø CLEANOUT
fu""
4'ø SCH 40 SE\¡./Eil P|PE
SÉPTIC IANK. 1.000 GALLON. 2-COtu1PARTMENT
SPP2
6-HOLE
DISTRIBUT¡ON BOX
4" ø SDR 35 0R
SCH 40
PIPE
16'
10'MtN
SPPl
PROFILE
SCALE: 1" = 20'
6
m
ı-
0)*ol
L =3.5't
S=45"
2'(rYP.)
2'
66
0+40
PROFILE CALLOUT NOTES
1 1 1+40 1 1
4'' Ø CLEANOUT WITHIN 5'OF BUILDING
4" Ø SCH 40 SEWER PIPE L= +80'
,1,OOO GALLON SEPTIC TANK
DROP PIPE 14'' BELOW INLET AND OUTLET
4" ø SDR 35 OR SCH 40 EFFLUENT PIPE L =
r2Q' S =10/o (;'7 FT) MtN.
6-HOLE DISTRIBUTION BOX, WITH RISER, SPEED LEVELERS & CONCRETE AROUND BASE
4" Ø SDR 35 OR SCH 40 DISTRIBUTION PIPE TOTAL L = +95'
END CAP (TYP. OF 8)
48" DRAINFIELD CHAMBER OF (TYP. OF12 PER LATERAL) (48 TOTAL)
4" Ø TNSPECTTON P|PE (TYP. OF 4)
NOIE: AN ALTERNAIIVE To USING A 2-WAY
CLEANOUT TEE. TWO APPOSING SINGLE
CLEANOUTS CAN BE USED.
4'ø SCH 40 PIPE
CAP
ù/
4 øSCH40
2-WAY
CLEANOUT TEE
TYPICAL DRAINFIELD TRENCH SECTION TWO-WAY CLEANOUT DETAIL INSPECTION PIPE DETAIL
SCALE 5/16 = 1'SCALE: 5/16" = I SCALE: 5/16 = 1'
I
OUICK4 PLUS STANDARD CHÂilBER
sEcnoN vt&
GARFIELD COUNTY OWTS DESIGN
PROFILE & DETAILS
SITE ADDRESS:
6800 cR 252
RIFLE, CO 8'r650
SHEET
30F4
For:
REUBEN & LISA JENSEN
PO BOX 445
CARLSBAD, TX 76934
By:
Headwater Engineering
P.O. BOX 1293
Craig, CO 81626
Revised:File:
Dete:Checked By: WAMDrawn By: WAM
nf iùalor &ler Tæhnobqes M 160 O.E.
=2 Tan
nfihalo¡ ftler Tæhhdooes Quick4 O E.
rdilite6-hde.t sÞeed!ælÉsând Lid Risd
1
580
80
1
1
115
QUANTITIES AND SPECIFICATIONS
Ruben Jensn
6800 cR 252 RTFLE 81650
Biil Materials
GROUND
SURFACE
1
a
J
4
5
6
7
Õ
I
0 - 1.5' SILTY LOAM,
RED TO DK, BROWN
1.5" 3,0' SANDY GRAVEL
WITH ROCK COBBLES 6"- 8"
4 SCH 4 CÈanoùllæ s
s
om
1l
-lT
1
_+
3,0' - 8.0' stLTY LOAM,
RED TO DK. BROWN
FG SAND
$wc6JNolès:
1 Al quadnies are approitoâle ând bã*d on desìln ñeasúedents feb m€surêmsts ad Wâñf€s may B¡y Estimates ar¿ tor ptaming
&brevat hsì A= Eadh. LÊ; Lìñear leet. SF= Sq€re fæl O E. = Or Equat
TYPICAL SOIL PROFILE LOG
SC^LE 1 =5
NOTES:
1.
2.
ENGINEER SHALL INSPECT SYSTEM INSTALLATION PRIOR TO BACKFILL. PLEASE NOTIFY ENGINEER
AT LÊAST 24 HOURS PRIOR TO REQUIRING INSPECTION,
SCH 40 PIPE SHALL BE USED UNDER DRIVEWAYS AND PARKING AREAS. SDR 35 CAN BE USED
ELSEWHERE ALTHOUGH SCH 40 IS RECOMI\¡ENDED. ALL FITTINGS SHALL BE SANITARY
FITTINGS. (PRESSURE FITTINGS SHALL NOT BE USED UNLESS SPECIFIED)
PIPE FITTINGS USED IN lHE SEWER LINE SHALL NOT EXCEED A 45' BEND AND WLL BE INSTALLED
WTH A CLEANOUT,
BACKSLOPE EXCAVATION FOR -TANK INSTALLATION IN ACCORDANCE WTH OSHA REGULATIONS {29
cFR PART 1926, SUBPART p, SECTTONS 1926.650 THROUGH 1926.652).
SEPÍ IC IANK SHALL BE TWO COI\¡PARII\¡ENT UNLESS OTHERWSE SPECIFIED. INSTALL TANK IN
ACCORDANCE VMTH MAN UFACTU RE'S RECOI\¡I\¡ENDATIONS.
MESH SCREEN CAN BE INSTALLED IN THE TRENCH BENEATH THE DRAINFIELD CHAMBERS TO
PREVEN'| ANIMAL ENTRANCE. BUT IS NOT REOUIRED.
BRUSH AND VEGETATION SHALL BE CLEARED FROI\¡ DRAINFIELD AREA PRIOR TO CONSIRUCTION.
IN AS I\,1UCH AS POSSIBLE ORIENT THE DRAINFIELD LATERALS PARALLEL WTH IHE HILL SLOPE,
NEITHER BEDROCK. GROUNDWATER NOR OTHER RESTRICTIVE LAYERS WERE ENCOUN-TERED IN THE
SOIL PROFILE PIT,
INSTALL ALL PIPE. DRAINFIELD CHAMBERS SEPTIC TANK, AND APPURTENANCES IN ACCORDANCE VUTH
IllANUFACTURES' RECOI\¡I\¡ENDATIONS AND LOCAL CODÊS.
ITISTHECONTRACTOR'SRESPONS¡BILI]-YTOLOCATEEXISTINGUlILITIES, UTILITIESWERENOT
VERIFIED VllTH THIS PROJECT.
ACTUAL FIELD LENGTHS AND DEPTHS OF THE CONSTRUCTED SYSTEI\4 ARE EXPECTED TO VARY. BUT
SHOULD BE WTHIN THÉ ¡iIINII\¡UI\¡S AND MAXI¡/U¡,4S AS SPECIFIED WTHIN THESË PLANS.
OFFSET DISTANCES
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9.
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GARFIELD COUNTY OWTS DESIGN
NOTES & CALCULATIONS
SITE ADDRESS:
6800 cR 252
RtFLE, CO 81650
SHEET
4UF 4
For:
REUBEN & LISA JENSEN
PO BOX 445
CARLSBAD, ÎX 76934
By:
Headwater Engineering
P.O. BOX 1293
Craig, CO 81626
COLORADO
Revised:
Dâle:Checked By: WAMDrawn Bv WAM