HomeMy WebLinkAboutOWTS Design Report 10.28.2020DESIGN REPORT
ON-SITE WASTEWATER TREATMENT SYSTEM (OWTS)
TBD CR 237
TRACT 28
SILT, COLORADO
GARFIELD COUNTY
October 28, 2020
Prepared By: Kenneth J. Brotsky, P.E.
558 Rio Oso Lane
Grand Junction, CO 81507
(970)216 8861
I. INTRODUCTION:
This Report has been prepared at the request of Kelley Dearth,
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:
The site is a sloping, high desert area, with ground slopes
generally about 11% to the north-northwest. There is sparse
desert vegetation with mesquite pine trees to the south of the
building site. The site is located nearly in the center of the
parcel of 12 acres.
Two test holes were dug in the general area of the proposed OWTS.
The upper 12" of soil is hard, cloddy, clay topsoil. From 12 to
30" there is tannish, silty, clay not as cloddy as above. From
30" to 98" there is a clayey, sandstone matrix. This material is
very chalky. The tactile examination indicates a somewhat non-
porous material which is not moldable when wetted. There is a
grittyish feel indicating that there is some silt present.
Percolation rates varied from 37 to 60 minutes per inch. Soil
observation and percolation rate each indicates a Soil Type 3
with a Long Term Acceptance Rate of 0.35 gallons per square feet
per day.
Because of the sloping topography (11%) 4 trenches will be used
spaced 6' apart with the absorptive surface at 32" below existing
grade.
III. SYSTEM DESIGN:
A. Estimated Sewage Flow: The proposed house will be 4
bedroom.
4 x 150 = 600 gallons per day
B. Septic Tank
Use a 1,250 gallon tank.
C. Absorption Bed:
The absorption bed size is calculated as
follows:
Adjustment Factors:
row
A = 600/.35
1714 sq. ft.
Table 5.2 Method of Application is gravity trench
Factor 1.0
Table 5.3 Type of Distribution is Chambers
Factor 0.70
Bed Size required is 1714 x 1.0 x 0.70 = 1200 Sq. Ft.
Total Number of chambers required is 1200/12 = 100 units
Use trench configuration, with 4 rows and 25 chambers per
for a total of 100 chambers.
KENNETH J. BROTSKY, PE „mr►>vr
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No. 18843
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PERCOLATION TEST DATA TABLE
ADDRESS: 7-‘3O - Z.17 -- %�4eT zer DATE 'Z - z z — 240 Z12
- u,e Pc <s TCS T
HOLE
DEPTH
O Se-(
3
TIME
/:'%a /2/4/0 //ia /:V ' Z//o
DROP
RATE
X1'1
RI"
AVE.
ATP/
-:y3''
Go- 7t''
SOIL PROFILE
D
E
P
T
H
3/5"" 3/,r" J4, a/0
3.4/"
34
3/v .
/8" 46''
cot (l4 y ThpSA
\/2 6r/T'#7,114 .5-/64�p
r-,-, 47# , ', C /y 4 i / ',
-3%s
3 3/b
-r SO/L S u/ ,fie= A/2E62047-.4.9 la C- - 4,c' a
0
yo
38
36'
RATE SLOWER THAN 60 MPI /✓ HOLE LOCATION DIAGRAM
RATE FASTER THAN 5 MPI A/
SLOPE GREATER THAN 30% N
HSWT DEEPER THAN 4 FT. y Re Po se",'
BEDROCK LESS THAN 4 FT. A/ i av se
FLOODPLAIN 41
ON-SITE WATER 7
REPAIR AREA
GWT, HSWT ------
COMMENTS:
flcD aC
40 ;". €.0 s
Le f of n/'.r 4/te-
rn 4
/trmL Re 77-/ pAJ 1 )a' _ /~!'I)''
J J X
DISTRIBUTION BOX
ADJUST SO EACH PIPE
OUTLET IS THE SAME
LEVEL FOR EQUAL
FLOW TO EACH TRENCH
1250 GALLON
SEPTIC TANK
I CLEANOUT -
PROPOSED HOUSE
4 BEDROOM
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5{'NrLE
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JAiFILrAra TOg
VRJa.z. 2 -'/e" ,4ucc-S
34'4/F AZ0/71 Barr'am
t/EN,I0t1.5Peen-e v P7-
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REPLACEMENT AREA
TOPOFHOU$E
FOUNDATION /00.0
- VENT/INSPECTION TUBE
FLOW -LINE PROFILE
SCHEMATIC
NOT TO SCALE
r 4c eFIL L. kv,'? V
.44 17,j 44.fre,e/Apz
QUICK 4 INFILTRATORS _
4 TRENCHES , 25 EACH
TRENCH =100 TOTAL
QUICK 4 INFILTRATORS
4 TRENCHES, 25 EACH
TRENCH = 100 TOTAL
SET BOTTOM OF INFILTRATORS
IN EACH TRENCH LEVEL
NORTH
SCALESCALE: 1"=Zi
: 1 "= 20,
NOTE IT IS CRUCIAL THAT
THE FLOW LINE OF THE PIPES
OUT OF THE DISTRIBUTION BOX
BE AT LEAST 12" ABOVE THE
INLET FLOW LINE INTO THE 1"
TRENCH INFILTRATOR.
SE T /3e //-/C L"/l/
„52"-/- 5/3 5CLOIA/
eace
d;' E'45P G/t/!>_
1
AA
,SCC7zA/
GE0%LX% /L E FM3R/C
SET BOTTOM OF INFILTRATORS
IN EACH TRENCH LEVEL,
I'LASTiC OR IEDPR LID
FLAT OR DOMED •
FASTEN TO RISER
24^ DIAMETER
HDPE RISER
USE END PLATE ON
EACH ROW"
VENT/INSPECTION PORTS
4 RQD
NOTE S
1. Contact Engineer for inspections at the following times: (Allow at
least 24 hours advance notice). (Engineer will coordinate inspection time
with Garfield County)
1) When installation of the infiltrators, piping, and
tank is complete but not covered, and ready for final inspection.
Engineer is Kenneth J. Brotsky
(970) 216-8861
septic
2. The pipe from the house plumbing to the septic tank and from the tank
to the distribution box shall be 4 inch diameter, SDR 35, PVC sewer pipe.
The pipe shall be laid.at a minimum slope of 1/4 inch per foot.
3. INFILTRATOR units to be installed per manufacturers recommendations.
Units to be "Quick 4". Geo -textile landscaping fabric' shall be draped over
the Infiltrators as shown.
4. Septic tank shall be 1,250 gallon, 2 compartment approved by Garfield
County.
5. All construction shall be in accordance with Garfield County On -Site
Wastewater Treatment System Regulations", most current edition.
6. Any 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".
8. An OWTS Permit must be obtained from Garfield County prior to starting
installation of system.
FINISH GRADE
1,•;•1 FASTEN TOTANK
TANK COVER
TANK RISER DETAIL
TANK WALL
SITE LAYOUT, DETAILS, & NOTES
ON-SITE WASTEWATER TREATMENT
SYSTEM (OWTS)
TBD - CR 237
TRACK 28
SILT, COLORADO
GARFIELD COUNTY
OCTOBER 29, 2020
DWG 1