HomeMy WebLinkAboutTract 6760 Sewer Study
Objective
The objective of this study is as follows:
1) The purpose of this study is to determine the sewer discharge from Tract 6760.
Existing Facilities
The proposed project site is currently undeveloped but is surrounded by developed land, with
existing residential subdivisions to the north and west and an existing Church to the east. An
existing residence (APN 532-040-03) and Taft Highway exists to the south of the project site.
Thirty three lots of Tract 6760 and the existing residence will discharge through the proposed 6”
sewer to an existing 8-inch sewer stub constructed with Phase 3 of Tract 6491 that will
ultimately discharge to the City of Bakersfield Wastewater Treatment Plant #3.
Planned Land Uses
Tract 6760 is a residential development and will consist of 33 single family dwellings. An
existing residence (APN 532-040-03), located between lots 25 & 26, will also utilize the
proposed sewer improvements.
Design
The proposed development will be serviced by an existing 8” sewer stub located at the Tract
Boundary on Agassiz Rock Way. The existing 8” sewer was constructed as part of Phase 3 of
Tract 6491. Our calculations, shown in the enclosed spreadsheet, show that the proposed system
has enough capacity to accommodate the 33 lots in Tract 6760 as well as the existing residential
lot. The capacity of the sewer mains were calculated using Manning’s Equation as shown below.
V = 1.486 R2/3S1/2 and Q = AV
n
Where “V” is the average velocity in feet per second
“n” is Manning’s coefficient
“A” is the area based on the pipe size
For plastic pipe: n = 0.011
1.486 = 135.091
n
“R” is the hydraulic radius in feet and “S” is the slope in feet per foot.
Sewer Main Allowable Flow Characteristics
8” @ 0.35% V = 135.091 x 0.303 x 0.059 = 2.415 fps
A = 0.349 sf
Q = 0.843 cfs
Sewer Main Allowable Flow Characteristics
6” @ 0.50% V = 135.091 x 0.25 x 0.0070 = 2.386 fps
A = 0.196 sf
Q = 0.469 cfs
Sewer Main Allowable Flow Characteristics
6” @ 1.00% V = 135.091 x 0.25 x 0.10 = 3.377 fps
A = 0.196 sf
Q = 0.663 cfs
Calculations are attached in spreadsheet form.
Results
Tract 6760 is a single phase project that will be serviced by an existing 8” Sewer Stub from
Phase 3 of Tract 6491. The system is designed to utilize 6” PVC pipe at 0.50% & 1.00%
throughout the site. An 8” sewer line is proposed along Agassiz Rock Way at a proposed slope
of 0.35% to tie into the existing sewer stub located near the Tract Boundary. The approved
Sewer Study for Tract 6491 included the discharge from Tract 6760 in its calculations. It is
calculated that the service area will generate 0.062 cfs (0.040 MGD) of sewer that will ultimately
discharge to the City of Bakersfield’s Wastewater Treatment Plant No. 3. The discharge from
this Tract has already been allocated as part of the Sewer Study for Tract 6491.
C.E.Q.A. Compliance
Development of the proposed project will not result in significant impacts to the existing and
proposed sewer collection and treatment facilities. The development will be serviced by the City
of Bakersfield’s Wastewater Treatment Plant No. 3 which has a current average daily flow of
17.3 MGD and a design capacity of 32 MGD.
Vicinity Map
TRACT
6760
NOT TO SCALE
SE
W
E
R
S
T
U
D
Y
2/
2
6
/
1
6
Tr
a
c
t
6
7
6
0
Mi
n
i
m
u
m
V
e
l
o
c
i
t
y
F
u
l
l
:
2
Ma
n
i
n
i
n
g
s
"
n
"
:
0
.
0
1
1
Cu
m
u
l
a
t
.
P
e
a
k
T
o
t
a
l
Re
q
'
d
.
D
e
s
i
g
n
C
a
p
a
c
i
t
y
SE
R
V
I
C
E
L
a
n
d
D
E
N
.
A
R
E
A
E
.
D
.
U
.
A
v
e
r
a
g
e
A
v
e
r
a
g
e
A
v
e
.
R
e
s
.
P
e
a
k
F
l
o
w
D
e
s
i
g
n
U
.
S
.
U
.
S
.
R
e
a
c
h
S
i
z
e
S
l
o
p
e
S
l
o
p
e
D
.
S
.
D
.
S
.
a
t
D
e
sign
AR
E
A
U
s
e
D
U
/
A
C
a
c
r
e
s
c
f
s
/
a
c
F
l
o
w
,
c
f
s
F
l
o
w
,
c
f
s
F
a
c
t
o
r
c
f
s
F
l
o
w,
c
f
s
M
.
H
.
I
N
V
.
l
e
n
g
t
h
I
n
c
h
e
s
I
N
V
.
M
.
H
.
S
l
o
p
e
,
c
f
s
In
i
t
i
a
l
D
e
v
e
l
o
p
m
e
n
t
Pi
p
e
5
S
F
3
0.
0
0
1
2
1
5
.
1
8
9
0
.
0
0
6
CO
1
33
9
.
4
4
83
6
0.
0
0
3
5
0
7
0.010000 338.61 4
0
.
6
6
3
Pi
p
e
4
S
F
2
0.
0
0
0
8
0
5
.
4
0
4
0
.
0
1
1
4
33
8
.
5
1
82
6
0.
0
0
3
5
0
7
0.010000 337.69 3
0
.
6
6
3
Pi
p
e
3
S
F
1
3
0.
0
0
5
2
3
4
.
4
8
2
0
.
0
3
4
3
33
7
.
6
9
40
0
6
0.
0
0
3
5
0
7
0.005000 335.69 1
0
.
4
6
9
Po
i
n
t
o
f
C
o
n
f
l
u
e
n
c
e
@
M
H
1
0.
0
0
7
2
4
0
.
0
3
4
3
33
5
.
5
6
31
4
8
0.
0
0
2
3
9
0
0.003500 334.46 TIE-IN
0
.
8
4
5
Pi
p
e
2
S
F
1
6
0.
0
0
6
4
3
4
.
3
8
9
0
.
0
2
8
2
33
9
.
4
6
37
6
6
0.
0
0
3
5
0
7
0.010000 335.69 1
0
.
6
6
3
Po
i
n
t
o
f
C
o
n
f
l
u
e
n
c
e
@
M
H
1
0.
0
0
6
4
3
0
.
0
2
8
2
33
5
.
5
6
28
5
8
0.
0
0
2
3
9
0
0.003500 334.46 TIE-IN
0
.
8
4
5
Pi
p
e
1
S
F
0.
0
6
2
1
33
5
.
5
6
16
5
8
0.
0
0
2
3
9
0
0.003500 334.96 TIE-IN
0
.
8
4
5
TO
T
A
L
S
:
34
0.
0
1
3
6
7
0.
0
6
2
<<
<
D
i
r
e
c
t
F
l
o
w
t
o
E
x
s
t
.
8
"
S
e
w
e
r
s
t
u
b
f
r
o
m
T
r
a
c
t
6
491 - Phase 3
P:
\
P
R
O
J
E
C
T
S
\
0
5
0
4
3
.
0
2
-
U
L
A
T
6
7
6
0
\
S
t
u
d
i
e
s
\
S
e
w
e
r
\
C
a
l
c
u
l
a
ti
o
n
s
\
0
5
0
4
3
.
0
2
S
S
0
1
.
x
l
s