HomeMy WebLinkAboutTract 6442 Sewer StudySEWER STUDY
Tract No. 6442
Objective
The objective of this study is as follows:
· To determine the sewer discharge from Tract 6442 at the three (3) separate tie-in points
to several existing sewer lines.
Existing Facilities
The site is currently undeveloped and surrounded by developed residential single lot family
homes to the south (Ex. Tract 6141) and east (Ex. Tract 6066). Berkshire Road exists to the
north with Stine Road to the west. Seventy seven lots of Tract 6442 will ultimately discharge
to the existing 30-inch sewer line on Stine Road and eventually to the Wastewater Treatment
Plant #3.
Planned Land Uses
Tract 6442 is a residential development that will consist of seventy seven (77) single family
dwellings and a drainage basin. Based on the City Planning & Land Use Map, this site is
listed as Low Density Residential thus a further downstream analysis will not be required.
Design
The proposed development will be serviced by an existing 10” sewer on Berkshire Road then
by an existing 30” sewer located on the westerly side of Stine Road, just south of Berkshire
Road. This existing 30” sewer runs southerly towards the McCutchen Road Trunk Line. Due
to the terrain and cover restrictions on site, we are proposing to construct 8” PVC sewer lines
at a slope of 0.35%.
Our calculations, as shown below and in the enclosed spreadsheet, illustrates that the
proposed 8” line will work for upstream of all connection points. Tract 6442 is expected to
generate a total of 0.101 cfs of sewage discharge. Here is a breakdown of the amount of
discharge at each Point of Connection:
1) Berkshire Road – Sta 23+26.63: 0.013 cfs
2) Berkshire Road – Sta 11+28.40: 0.017 cfs
3) Stine Road – Sta 7+79.11: 0.071 cfs
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” @ 0.350% V = 135.091 x 0.304 x 0.059 = 2.423 fps
A = 0.349 sf
Q = 0.845 cfs
Calculations are attached in spreadsheet form.
Results
Tract 6442 has been divided into three (3) separate sewer systems with three different points
of connection to the existing sewer. It is calculated that the project will generate a total of
0.101 cfs of sewer. The system is designed to use 8” PVC pipe at 0.35% throughout most of
the site. The last 100 feet of all reaches are 6” PVC at 1%. The lots fronting Berkshire Road
will discharge into two (2) separate existing manholes on this street. Point of Connection #1
will be located at the intersection of Berkshire Road & Sherwood Forest Road. Point of
Connection #2 will be located several feet east of the Berkshire Road & Stine Road
intersection. The third tie-in point, Point of Connection #3, will be located at an existing
manhole, located on Stine Road adjacent to the proposed sump, thus discharging directly into
the existing 30” sewer line. The residential lots tributary to this sewer system will handle all
within the development and not homes that front Berkshire Road. The cumulative flow will
eventually discharge to the Wastewater Treatment Plan No 3.
The sewer system within the tract is very shallow. We are able to provide minimum cover by
using PVC pipe and minimizing the slope of the pipe to 0.35%. These three sewer systems
will only service Tract 6442.
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 currently has a capacity of
32.0 million gallons per day.
Blaine Neptune
R.C.E. 55102
SEWER STUDY11/16/20Tract 6442Minimum Velocity Full: 2Maninings "n": 0.011Cumulat. Peak TotalReq'd. Design CapacitySERVICE Land DEN. AREA E.D.U. Average Average Ave. Res. Peak Flow Design U.S. U.S. Reach Size Slope Slope D.S. D.S. at DesignAREA Use DU/AC acres cfs/ac Flow,cfs Flow,cfs Factor cfs Flow,cfs M.H. INV. length Inches INV. M.H. Slope, cfsInitial Development6" PVC SF 20.00062 5.548 0.003CO2352.38100 60.0035070.010000351.384 0.6638" PVC SF 60.00186 4.971 0.0134351.24310 80.0023900.003516350.156 0.847Point of Connection #1 @ Sta. 23+26.638TOTAL0.00247 0.0136350.0534 80.0023900.004706349.89PC-1 0.9806" PVC SF 20.00062 5.548 0.003CO1351.13100 60.0035070.010000350.133 0.6636" PVC SF 20.00062 5.548 0.0073350.13170 60.0035070.005000349.282 0.4698" PVC SF 70.00216 4.895 0.0172349.14400 80.0023900.003500347.741 0.845Point of Connection #2 @ Sta. 11+28.4011TOTAL0.00340 0.0171347.6434 80.0023900.015588347.11PC-2 1.7838" PVC SF58TOTAL0.01793 3.962 0.0717347.11226 80.0023900.004206346.16PC-3 0.926Point of Connection #3 @ Sta. 7+79.110.02134 0.0717347.11226 80.0023900.004206346.16PC-3 0.926P:\PROJECTS\20044.00-TR6442\Studies\Sewer\Calculations\20044SS01.xls
Point of Connection #2Point of Connection #1Point of Connection #2Point of Connection #1Point of Connection #1Point of Connection #1NOTE:
INVERTS MAYBE DIFFERENT
DUE TO THE DATUM BUT THE
PROPOSED SIZES, PIPE
LENGTHS, AND PIPE SLOPES
WILL REMAIN THE SAME AS
THESE PLANS.
Point of Connection #3Point of Connection #3NOTE:
INVERTS MAYBE DIFFERENT
DUE TO THE DATUM BUT THE
PROPOSED SIZES, PIPE
LENGTHS, AND PIPE SLOPES
WILL REMAIN THE SAME AS
THESE PLANS.
SEWER EXHIBITLEGEND:
Lots discharging to the
Point of Connection #1
Lots discharging to the
Point of Connection #2
Lots discharging to the
Point of Connection #3
8 Lots
11 Lots
58 Lots
LEGEND:
Lots discharging to the
Point of Connection #1
Lots discharging to the
Point of Connection #2
Lots discharging to the
Point of Connection #3
8 Lots
11 Lots
58 Lots