HomeMy WebLinkAboutOWTS Design Report 07.26.17DESIGN REPORT
ON-SITE WASTEWATER TREATMENT SYSTEM (OWTS)
901 ODIN ROAD
SILT, COLORADO
GARFIELD COUNTY
Prepared By: Kenneth J. Brotsky, P.E.
558 Rio Oso Lane
Grand Junction, CO 81507
{970)216 8861
I. INTRODUCTION:
JULY 26, 2017
This Report has been prepared at the request of Clayton Homes
representative for the above referenced property. This Report
addresses the design of an On-Site Wastewater Treatment System to
serve a proposed residence. Public sewer service is not
available.
The procedures used in this report follow the "Garfield County
.On-Site Wastewater Treatment System Regulations".
II. SOILS AND PERCOLATION TEST:
A test hole was dug in the area of the proposed absorption field
and observed by the Engineer on May 31, 2017. The upper 12" of
soil is brown, loamy clay topsoil. From 12" to 32" the material
is hard, chalky limestone powder containing traces of caliche. At
32" to 90" the soil is powdery, chalky, limestone, softer than
the above material. At 90" limestone bedrock was encountered.
The ground surface where the OWTS absorption bed will be built
slopes at about 1 to 2% to the southeast.
Percolation rate in the 12 to 32" layer was 25 minutes per inch.
In the 32 to 90" layer the percolation rate was faster, averaging
16 minutes per inch. The soil is characteristic of somewhere
between a Type 2 and a Type 1. Therefore a Long Term Acceptance
Rate of 0.7 gallons per square foot per day will be used.
The bottom of the absorption bed will be set 30" below existing
grade at the northeast corner of the bed.
III. SYSTEM DESIGN:
A. Estimated Sewage Flow: ( 3 bedrooms)
3 x 150 = 450 gallons per day
B. Septic Tank
Use a 1,000 gallon tank
C. Absorption Bed:
The absorption bed size is calculated as
follows:
A ,.,,450/.70
= 643 sq. ft .
. Adjustment Factors:
Table 5.2 Method of Application is Dosed Bed
Factor 1.2
Table 5.3 Type of Distribution is Chambers
Factor 0. 70
Bed Size required is 643 x 1.2 x 0.70 = 540 Sq. Ft.
Total Number of chambers required is 540/12 45 units
Use bed configuration, with 4 rows and 12 chambers per r o w
for a total of 48 chambers.
No . 18 8 4 3
PERCOLATION TEST DATA TABLE
901-CJD/ Ii i2 o.
ADDRESS:sJLr. fa DATE S-/31/1 7 •
HOLE DEPTH
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SOIL PROFILE
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DROP RATE AVE.
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RATE SLOWER THAN 60 MPI //
RATE FASTER THAN 5 MPI '/
SLOPE GREATER THAN 300/o Jl
HOLE LOCATION DIAGRAM
---HSWT DEEPER THAN 4 FT._....Y.__
BEDROCK LESS THAN 4 FT. A/
FLOODPLAIN /\/
ON-SITE WATER t.J~t..t.. --------REPAIRAREA.~---~~~~~-
GWT HSWf -------COMMENTS:
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WATER SERVICE
(~tUST HAVE A l\UNIMUl\1
OF 25' Sf.PARA TION
FROM ABSORPTION BED
& SEPTIC TANK
"QUICK-4 STD"
INFILTRATORS.4 ROWS
12 EACH ROW• 48 TOTAL
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1000 GALI.ON SEPTIC
TANK. SEE NOTE 4
,.SEE MANIFOLD DETAIL t ~i
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VENT/INSPECTION roRTS
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GEOTEXTILE FABRIC ••• :,l_
;--DRAPED OVER INFB.ntATORS ~----f-,.-\---.:'--.
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SET BOTIO!\I OF IN FI LTRATORS
l.EVEL 24" BEi.OW EXISTING
GRADE AT NORTHEAST CORNER
NOTES
1. Contact E:ngineer for inspections at the following timez:
(Allow at least 24 hours advance notice). (Engineer will
coordinate inspection time with Garfield County)
1) When installation of the infiltrators, piping, and
septic tank is complete and ready for final inspection.
Engineer is Kenneth J. Brotsky (970) 216-8861
2 . The pipe from the house plumbing to the septic tank shall be
4 inch diameter, SOR 35, PVC sewer pipe. The pipe sha 11 be
laid at a minimum slope of l/B" per foot.
3. INE"ILTRATOR uni ts to be installed per manufacturers
recommendations. Uni ts to be "Quick 4 standard ( 3' x 4' x 13") .
Geo-textile landscaping fabric shall be draped over the
infiltrators as shown.
4. The septic tank shall be a 1,000 gallon, 2-compartment tank
approved by Garfield County.
5. All construction shall be in accordance with Garfield County
On-Site Wastewater Treatment System Regulations", most current
edition.
6. 1\ny changes to the layout on these drawings must have the
approval of the Engineer prior to construction . Any unauthorized
changes may have to be corrected . Any costs for redrawing of
plans required because of unauthorized changes may be back
charged to the installer.
7. Installer responsible for calling for "Locates".
4 ROWS INFILTRATORS
4~14"14"TEE ~
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4"s'J9"Bf.ND [j 1 ~
~USE SIDE INLETS
MANIFOLD DETAIL
I SITE PLAN, DETAILS, & NOTES
I-
ON-SITE WASTEWATER TREATM ENT
SYSTEM (OWfS)
901 ODIN ROAD
GARFIELD COUNTY, CO
JULY26, 2017 DWG I OF I