HomeMy WebLinkAboutEngineers Design Report 05.17.2018DESIGN REPORT
ON-SITE WASTEWATER TREATMENT SYSTEM (OWTS)
11084 CR 311
SILT, COLORADO
GARFIELD COUNTY
May 17, 2018
Prepared By: Kenneth J. Brotsky, P.E.
558 Rio Oso Lane
Grand Junction, CO 81507
(970)216 8861
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I. INTRODUCTION:
This Report has been prepared at the request of Pete Grover,
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 15, 2018. The soils are
ancient alluvial material. The upper 12" of soil is black,
loamy, clay, mountain topsoil. From 12" to 38" the material is a
biege, silty clay. At 38" to 96" the soil is a light tan, silty,
sandy clay with some caliche.
The ground surface where the OWTS absorption bed will be built
slopes at about 5 to 6% to the northwest.
Percolation rate averaged from 8 to 15 minutes per inch. The
soil type is somewhere between type 1 and 2, so for design
purposes, a Long Term Acceptance Rate of 0.7 gallons per square
foot per day will be used.
It is desirable to put the bottom of the absorption bed in the
material which is 38" below the existing grade.
III. SYSTEM DESIGN:
A. Estimated Sewage Flow: The proposed house will be 3 bedroom,
however the hoomeowner wishes to design and construct a system
for 4 bedrooms.
4 x 150 = 600 gallons per day ...;25
B. Septic Tank
Use a 1,250 gallon tank
C. Absorption Bed:
follows:
The absorption bed size is calculated as
525 /
A= 6<0'b/.70 6 Z 5/ 7 Z 750
857 sq. ft.
Adjustment Factors:
Table 5.2 Method of Application is Gravity Trench
Factor 1.0
Table 5.3 Type of Distribution is Ch
Factor 0.70
szs
Bed Size required is 750 x 1.0 x 0.70 = 6 Sq. Ft.
Total Number of chambers required is 600/12 = 50 units
Use trench configuration, with 2 trenches and 25 chambers
per trench for a total of 50 chambers.
KENNETH J. BROTSKY,
No. 18843
PERCOLATION TEST DATA TABLE
ADDRESS: //6891'- e21/
DATE 5-///6//8
HOLE
#
DEPTH
iz o s
TIME
i
.' 3
�
3 G Mi u
("so
DROP
RATE
/1/ArrTpI
AVE.
CO
4'o -5'/h
2 53/4,
33//
8
/z-3/; s, c ry C'cA y
. 38-9e." 4iGilr 74N SIc7 y e,..4,
It)/ 54...w 0L/-(6-•
7QLLue.m4G o�.0
D/G S
/�,vG/E� r
C
ez-34
z y
z
/s
a
34 Y7
/'// y yy
3
'
SOIL PROFILE
D
E
P
T
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l
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v-iz" 84.AA /s1irV, r p »
iz
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9L *
/oS _
/z-3/; s, c ry C'cA y
. 38-9e." 4iGilr 74N SIc7 y e,..4,
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7QLLue.m4G o�.0
D/G S
/�,vG/E� r
RATE SLOWER THAN 60 MPI A/
RATE FASTER THAN 5 MPI A/
SLOPE GREATER THAN 30% A/
HSWT DEEPER THAN 4 FT. 5
BEDROCK LESS THAN 4 Ff. n/
FLOODPLAIN
ON-SITE WATER= ‘-
REPAIR AREA
GWT IISWT
COMMENTS:
TESTED BY: '� /i+ : 'c •
_'
SIGNATURE
HOLE LOCATION DIAGRAM
r),,EQPO f..r
frite
SEE MANIFOLD DETAIL,
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CLEANOIIT
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roc- rim
NOTE:
1250 GALLON
SEPTIC TANK
SEE NOTE 4
SET TEE AND MANIFOLD
• PIPE LEVEL
' ELBOW DOWN TO
LOWER INFILTRATOR
QUICK-41NFIL"
TRENCHES, 2'
TRENCH = 50 T
NORTH
SCALE: 1" = 20'
'INFILTRATORS_
4"PVC PIPE e
FROM TANK
4"R4"X4"TEE
4"x B$ND=
MANIFOLD DETAIL