HomeMy WebLinkAboutCT 04-11; Poinsettia Commons; Sewer Report; 2007-04-02SEWER REPORT
POINSETTIA COMMONS
April 2,2007
Prepared For:
CITY OF CARLSBAD
RECORD COPY
Initial Date
Curtis'j. f urkW
Registration Expires
Prepared By:
PROJECTDESIGN CONSULTANTS
PLANNING • ENVIRONMENTAI • ENGINEERING • SURVEY/GPS
701 B Street, Suite 800, San Diego, CA 92101
619-235-6471 FAX 619-234-0349
Job No. 3153.00
RCE 59285
6/30/07
Prepared By: RB
Checked By: NP
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1.0 INTRODUCTION
This sanitary sewer report has been prepared to document the final design and supporting
calculations for the sewer system associated with the proposed development of Poinsettia
Commons within the City of Carlsbad. The sewer system for the development will connect to an
existing sewer main under Embarcadero Lane.
2.0 DESCRIPTION OF STUDY AREA
The property consists of approximately 5.92 acres of developed land located in the vicinity of
Embarcadero Lane and Avenida Encinas in the western portion of Carlsbad, California. The
property is bounded on the north and east by Avenida Encinas, on the south by Bay Lane, and to
the west by the North County Transit District.
3.0 PROPOSED SANITARY SEWER IMPROVEMENTS
The proposed private sewer system consists of an 8" PVC sewer main and 9 access holes
connecting to an existing 8" sewer under Embarcadero Lane. Individual 6" PVC private sewer
laterals will service the buildings on site and each will be connected to the 8" main. Eastlake
Village Limited Edition LLC proposes to develop approximately 75,212 square feet of
commercial, retail, lofts, and live/work facilities.
4.0 ESTIMATED SEWAGE FLOW (DEMAND)
According to the Carlsbad Standard Sewer System Design Criteria manual, sewage demand is
approximated as 220 gallons per dwelling unit for an average day. The Carlsbad Municipal
Water District Sewer master Plan (1993) states that every 1,800 SF of building space is
equivalent to 1 dwelling unit (EDU). Therefore and average sewage demand is equated by
P:\3153\ENGR\REPORTS\SWR\3153SEWERREPORT2007-04-02.DOC
dividing the total square feet of building space by 1800 and multiplying this number by 220
gallons per day. See table 1 for these quantities.
5.0 DESIGN CRITERIA
Where D = pipe diameter, and d = flow depth:
8-inch diameter pipe:
1. Maximum Depth at Peak Flow = Yz pipe diameter (0.5 feet) or d/D < 0.50
2. Minimum Pipe Slope = 0.40%, desirable 0.5%
3. Minimum Sewage Flow Velocity = 2 feet/second
4. Peaking Factor = 2.50
5. Unit Flow Generation Factor = 1 EDU/1,800 SF of building space
6. Sewage Generated = 220 gallons/EDU/day
7. Pipe Roughness Coefficient 'n' = 0.011 for PVC pipe
Design calculation equations were obtained from the City of Carlsbad Engineering Standards,
Volume 1, Chapter 6, 2004 Edition. Maximum sewer depth shall be 15 feet. Depths greater than
15 feet require approval from the City Engineer.
6.0 CONCLUSION
In conclusion, it was determined that the proposed 8-inch PVC pipe is suitable to carry the
service flow without exceeding the criteria depth of peak flow < Yz pipe diameter or d/D < 0.50.
The pipes' minimum velocity and slope requirements were maintained. The sewer depth ranges
from 1.7-feetto 14.8-feet maximum.
P:\31S3\ENGR\REPORTS\SWR\3153SEWERKEPORT2007-04-02.DOC
Project Design Consultants
701 "B" Street Suite 800
San Diego CA 92101
PDC job #3153.00
Date: 04/02/07
TABLE 1
SEWER FLOW CALCULATIONS
POINSETTIA COMMONS
Pipe Section by
Manhole
A-MH 1
C-D
D-E
E-F
F-G
G-B
B-MH1
MH1 - Ex. MH 1
H-l
I-J
J - Ex. CO
Ex. CO - Ex. MH
1
Ex. MH - Ex. MH
2
PP Area 5
Bldg. Area
(SF>
24742
22710
29070
29070
29070
25560
14634
0
8435
17125
0
0
0
0
Generation
Factor
(EDU)
13.75
3.00
3.00
3.00
3.00
3.00
3.00
0.00
4.65
9.44
0.00
0.00
0.00
100.00
Avg daily
flow (qpd)
3024
660
660
660
660
660
660
0
1023
2077
0
0
0
22000
Peak
Factor
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
Q-gpd
Peak/
Section
7560
1650
1650
1650
1650
1650
1650
0
2558
5192
0
0
0
55000
Q-gpd
Peak/
Total
7560
1650
3300
4950
6600
8250
9900
17460
2558
7750
7750
7750
25210
80210
Q-cfs
Peak/
Section
0.0117
0.0026
0.0051
0.0077
0.0102
0.0128
0.0153
0.0000
0.0040
0.0080
0.0000
0.0000
0.0000
0.1241
Q-cfs
Peak/
Total
0.0117
0.0026
0.0077
0.0153
0.0255
0.0383
0.0536
0.0653
0.0040
0.0120
0.0120
0.0120
0.0773
0.2014
Slope
0.0789
0.0110
0.0110
0.0110
0.0110
0.0110
0.0110
0.2080
0.0767
0.3169
0.3169
0.3133
0.0040
0.0040
n
0.011
0.011
0.011
0.011
0.011
0.011
0.011
0.011
0.011
0.011
0.011
0.011
0.011
0.011
D{ft)
0.670
0.670
0.670
0.670
0.670
0.670
0.670
0.670
0.670
0.670
0.670
0.670
0.670
0.670
Area-half
(sf)
0.176
0.176
0.176
0.176
0.176
0.176
0.176
0.176
0.176
0.176
0.176
0.176
0.176
0.176
Hyd Rad
(ft)
0.0235
0.0139
0.0232
0.0314
0.0395
1.0395
0.0293
0.0346
1.0346
2.0346
0.0127
0.0127
0.0790
0.1200
v (ft/sec)
2.5200
0.8100
1.1400
1.3900
1.6200
1.8300
2.0200
6.0000
1.8200
4.1400
4.1400
4.1300
1.5800
2.0800
Q-cap
(cfs)
0.4442
0.1428
0.2010
0.2450
0.2856
0.3226
0.3561
1 .0577
0.3208
0.7298
0.7298
0.7280
0.2785
0.3667
Excess
Cap (cfs)
0.4325
0.1402
0.1959
0.2374
0.2754
0.3098
0.3408
1.0577
0.3169
0.7218
0.7298
0.7280
0.2785
0.2426
d"
0.03
0.02
0.03
0.05
0.06
0.07
0.09
0.05
0.02
-6710.87
0.02
0.02
0.13
0.21
d/D
0.04
0.03
0.04
0.07
0.09
0.10
0.13
0.07
0.03
-10016.22
0.03
0.03
0.19
0.31
NOTE:
An existing sewer report or sewer study for the neighboring Poinsettia Properties Area 5 could not be obtained. The final d/D ratio of 0 32 was calculated by assuming that the Poinsettia Properties Area 5 neighborhood
to the north of Embarcadero Lane contains 100 single family dwelling units. The flow value from this area was then added to the flow from the new construction to calculate the final ratio.
The maximum d/D ratio for an 8" sewer line is 0.5. In conjuction with the proposed flow from Poinsettia Commons, the Poinsettia Properties Area 5 would need to have approximately 492 single family dwelling units
in order to achieve a d/D ratio of 0.50. In referencing the as-built plans for Poinsettia Properties Area 5 (City of Carlsbad Dwg. No. 378-9), it is apparent that significantly less than 492 units were constructed.
Therefore, one can conclude that the existing 8" sewer main under Embarcadero Lane will be sufficient to convey the current flow from Poinsettia Properties Area 5 and the additional flow from the Poinsettia
Commons project.
** = calculated in Flowmaster
^EXISTING
EXISTING
MANHOLE 2
0 25 50
GRAPHICAL SCALE
SCALE: 1" = 50'
PRQJECrDESIGN CONSULTANTS
PLANNING « BNVMONMBNIAL » ENODOBRIND »SUKVEWGBS
701 B Street, Suite 800, San Diego, CA 92101
619-235-6471 FAX 619-234-0349
COMMONS
SEWER REPORT
CHAPTER 6 - DESIGN CRITERIA FOR GRAVITY SEWER LINES AND
APPURTENANCES
Engineer will submit a rough layout of system for review and approval by the City Engineer prior
to preparation of improvement plans.
1. SEWER MAIN DEPTH AND SIZE
A. Sewer main depth and size shall be as shown below unless approved by the City
Engineer.
B. Minimum depth, finish grade to top of pipe 6 feet
C. Maximum depth, finish grade to top of pipe 15 feet
D. Design calculations shall be submitted to verify size and bedding design. (Manning
"N"PVC = 0.011 is norm).
E. Minimum size of mainline shall be 8".
F. 6" main line will be allowed on cul-de-sac streets with a maximum of 10 units.
G. All sewer laterals and main line invert elevations shall be shown in profile on the
improvement plans and shall include stations, slope, and distance.
H. All sewer mains over 15" in diameter shall require special design and City Engineer
approval.
2. SEWER LATERAL DEPTH AND SIZE
A. 4" minimum diameter for single-family residence.
B. 6" minimum diameter for all other use.
C. Desirable depth at property line is 5 feet (top of pipe to finish grade @ top of curb).
3. PIPELINE MATERIAL TYPES
A. Gravity sewer pipe and fittings shall have PVC conforming to ASTM D3034 for
diameters 4" - 15" and ASTM F 679 for 18" - 24", with integral-bell gasketed joints
(gasket and spigot end joint design). Pipe shall be made of PVC plastic having a
cell classification of 12454-B or 12364-B as defined in ASTM D 1784 and shall have
SDR of 35 and a minimum stiffness of 46 psi according to ASTM D 2412.
B. All fittings and accessories shall be as manufactured and finished by the pipe
supplier or approved equal and have bell and spigot configurations compatible with
that of the pipe.
Page 1 of 12
C. PVC pipe joints shall be elastomeric gasket joints type conforming to Standard
Specifications for Public Works (Greenbook) most recent edition. Rubber gaskets
shall be factory installed and conform to ASTM F 477. Pipe joints shall have been
tested and meet watertight performance requirements of ASTM D 3212, "Joints for
Pipe Using Flexible Elastomeric Seals."
D. PVC C-900 shall be used for gravity sewer pipelines with depths equal or greater
than 15 feet.
E. Use of other pipe and fitting materials and types may be required by the City
Engineer to meet specific conditions during design or construction.
F. Service connections to the sewer main shall be watertight and not protrude into the
sewer pipe. All materials used to make the service connections shall be compatible
with each other and with the pipe material to be joined and shall be corrosion proof.
G. Couplings used for repair, or transition to dissimilar pipe materials shall be
approved by the City Engineer and provide corrosion proof watertight seal.
DESIGN PARAMETERS FOR SEWER MAIN SLOPE. FLOW AND DEMAND
A. Gravity sewer pipelines shall be designed for a minimum velocity of 2 feet/second.
Velocity unless otherwise stated shall be calculated from peak dry weather flow.
B. Pipeline slopes shall satisfy the minimum velocity requirement aforementioned.
Maximum velocities greater than 10 ft/second should be avoided.
Slopes for Specific Pipe Sizes 8 through 12-inch diameter:
1) 8" minimum 0.40% desirable 0.50%
2) 10" minimum 0.28% desirable 0.40%
3) 12" minimum 0.21% desirable 0.30%
Slopes for larger than 12-inch diameter pipe shall be designed to meet flow and
velocity criteria and require specific approval of the City Engineer. Pipelines with
horizontal curvature will require increase slope to achieve minimum required
velocities.
C. 10" and smaller depth of peak flow Yz diameter
12" and above depth of peak flow % diameter
D. Gravity pipelines with diameters of 12" and less shall be designed to flow at depths
of 0.5D during peak flow. Gravity pipelines with diameters greater than 12" shall be
designed to flow at depths of 0.75D during peak flow.
Page 2 of 12
'.. Flowrate Generation
1) An Equivalent Dwelling Unit (EDU) = 220 gal/day, Average Daily Flow (ADF)
2) A peaking factor (PF) of 2.5 multiplied times the ADF shall be used to
determine Peak Daily Flows (PDF). PDF = ADF x 2.5
a) Residential: Single Family Residence = 1 EDU
b) Commercial Property: 1 EDU/1,800 ft2 (building space)
i) To convert raw land to square feet of building space, assume
30% coverage. This could vary significantly dependent
development constraints.
ii) To convert improved pads to square feet of building space,
assume 40% of coverage.
3) Industrial Property: 1 EDU/5,000 ft2 (warehouse space)
1 EDU/1,800 ft2 (office space)
a) To convert raw land to square feet of building space, assume 30%
coverage. This could vary significantly dependent issues such as
environmental restrictions.
b) To convert improved pads to square feet of building space, assume 40%
of coverage.
c) Assume 60% of building space is warehouse, and 40% is office space.
HORIZONTAL AND VERTICAL LAYOUT
A. Streets: See City of Carlsbad Standard Drawing No. GS6 for location.
Alley: Main to centerline shall be a minimum of three feet (3') offset.B.
C.
D.
Private Street: Shall require special design and conditions. Easement shall be
20 feet.
Horizontal Curve: SDR 35, PVC pipe may be curved horizontally with the
following limitation:
Pipe Diameter
(SDR 35)
6-inch
8-inch
1 0-inch
12-inch
1 5-inch
1 8-inch
Minimum Radius
of Curvature
150 feet
200 feet
250 feet
300 feet
375 feet
450 feet
City Engineer shall approve curvatures for larger diameter pipe.
Page 3 of 12