HomeMy WebLinkAboutTract 7044 Sewer StudyTract No. 7044 – Residential Project
SEWER STUDY
2
Objective
The objective of this study is as follows:
1) The purpose of this study is to determine the sewer discharge from Tract 7044 and
to determine if any surrounding areas may be served by a main line extension.
Existing Facilities
The site is currently undeveloped and surrounded by undeveloped land to the south with
the Independence High School site to the east. Mountain Vista Drive to the west and
future Tract 7043 is planned for the land to the south. Berkshire Road exists to the
north. Tract 7044 and future Tract 7043 will discharge to an existing 48-inch sewer line,
part of the McCutchen Road Trunk, and ultimately to the Wastewater Treatment Plant
#3.
Planned Land Uses
Tract 7044 is a residential development and will consist of 131 single family dwellings
and part of a drainage basin. Tract 7043 may be developed up to 206 single family
dwellings (based on 6,000 sq ft lots) at a future date.
Phasing
The project consists of two phases and a future development to the south. Phase 1
contains 74 single family homes and Phase 2 contains 55 single family homes and,
future Tract 7043 assumes 206 single family homes (6,000 sq ft lots) on its 28.33 acres.
This acreage only involves the buildable area and omits the proposed park area and
McCutchen Road.
Design
The proposed development will be serviced by and connecting to an existing 48” sewer
located on the north side of McCutchen Road, just west of Independence High School.
The existing 30” sewer was constructed as part of McCutchen Road Trunk Line. Due to
the terrain and cover restrictions, we are proposing to construct 8” PVC sewer lines at a
minimum slope of 0.25%.
Our calculations, shown below and in the enclosed spreadsheet, show that the proposed
8” line will work. Tract 7044 is expected to generate 0.245 cfs of sewer. All of Tract
7043, which is to be developed at a future date, will generate a flow of 0.281 cfs, shown
in Extension Pipe. The overall discharge produced for the developed condition is 0.527
cfs.
Tract No. 7044 – Residential Project
SEWER STUDY
3
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” @ 0.250% V = 135.091 x 0.304 x 0.050 = 2.053 fps
A = 0.349 sf
Q = 0.72 cfs
Calculations are attached in spreadsheet form.
Results
Tract 7044 has been divided into two phases and the sewer has been design to serve
each phase as it is constructed. It is calculated that the project will generate 0.527 cfs of
sewer. The system is designed to use 8” PVC pipe at 0.25% throughout most of the site.
The last 100 feet of all reaches are 6” PVC at 1%. The site discharges to an existing
manhole on the north side of McCutchen Road, an invert of 324.30 will be used at this
connection point. The existing manhole is already part of the McCutchen Road Trunk
line which discharges to the Wastewater Treatment Plan No 3.
Tract No. 7044 – Residential Project
SEWER STUDY
4
Vicinity Map
________________________________
____________________________________________________________Not to Scale
RESIDENTIAL PROJECT
P:\PROJECTS\15008.00-OLDRIVER\Studies\SEWER\Calculations\ 15008SS01.xls
SEWER STUDY 8/27/19
Tract 7044
Minimum Velocity Full:2
Maninings "n":0.011
Cumulat.Peak Total Req'd.Design Capacity
SERVICE Land DEN.AREA E.D.U.Avg.Average Ave. Res.Peak Flow Design U.S.U.S.Reach Size Slope Slope D.S.D.S.at Design
AREA Use DU/AC acres cfs/ac Flow,cfs Flow,cfs Factor cfs Flow,cfs M.H.INV.length Inches INV.M.H.Slope, cfs
Initial Development
PIPE 16 SF 4 0.00161 5.042 0.008 SSCO-03 338.65 175 6 0.003507 0.010000 336.90 SSMH-23 0.663
PIPE 8 SF 4 0.00161 5.042 0.008 SSCO-02 338.78 100 6 0.003507 0.010000 337.78 SSMH-25 0.663PIPE 7 SF 11 0.00442 4.557 0.028 SSMH-25 337.65 260 8 0.002390 0.003000 336.87 SSMH-23 0.782
Point of Confluence @ MH 23 0.00764 0.036 SSMH-23 336.77 130 8 0.002390 0.002500 336.44 SSMH-22 0.714
PIPE 15 SF 12 0.00482 4.518 0.022 SSMH-27 340.68 369 6 0.003507 0.009973 337.00 SSMH-26 0.662
PIPE 14 SF 4 0.00161 5.042 0.008 SSCO-04 338.74 175 6 0.003507 0.009943 337.00 SSMH-26 0.661
Point of Confluence @ MH 26 0.00643 0.030 SSMH-26 336.86 170 8 0.002390 0.002500 336.44 SSMH-22 0.714
PIPE 13 SF 2 0.00080 5.404 0.034 SSMH-26 336.86 170 8 0.002390 0.002500 336.44 SSMH-22 0.714
PIPE 6 SF 1 0.00040 5.792 0.039 SSMH-23 336.77 130 8 0.002390 0.002500 336.44 SSMH-22 0.714
PIPE 5 SF 0 0.00004 7.215 0.073 SSMH-22 336.34 290 8 0.002390 0.002500 335.62 SSMH-17 0.714
PIPE 12 SF 9 0.00362 4.649 0.017 SSMH-21 340.41 243 6 0.003507 0.010029 337.97 SSMH-20 0.664
PIPE 11 SF 9 0.00362 4.649 0.034 SSMH-20 337.84 400 8 0.002390 0.002500 336.84 SSMH-19 0.714
PIPE 10 SF 7 0.00281 4.768 0.047 SSMH-19 336.74 245 8 0.002390 0.002500 336.13 SSMH-18 0.714PIPE 9 SF 8 0.00322 4.705 0.062 SSMH-18 336.13 245 8 0.002390 0.002500 335.52 SSMH-17 0.714
Point of Confluence @ MH 17 0.02859 0.062 SSMH-17 335.52 123 8 0.002390 0.002500 335.21 SSMH-16 0.714
PIPE 20 SF 3 0.00121 5.189 0.006 SSCO-01 338.07 165 6 0.003507 0.010000 336.42 SSMH-14 0.663PIPE 19 SF 12 0.00482 4.518 0.028 SSMH-14 336.29 400 8 0.002390 0.002500 335.29 SSMH-13 0.714
PIPE 18 SF 11 0.00442 4.557 0.048 SSMH-13 335.29 400 8 0.002390 0.002500 334.29 SSMH-12 0.714
PIPE 17 SF 6 0.00241 4.842 0.060 SSMH-12 334.19 297 8 0.002390 0.002500 333.45 SSMH-11 0.714
PIPE 4 SF 4 0.00161 5.042 0.144 SSMH-17 335.52 123 8 0.002390 0.002500 335.21 SSMH-16 0.714
PIPE 3 SF 5 0.00201 4.931 0.153 SSMH-16 335.11 315 8 0.002390 0.005000 333.55 SSMH-11 1.010
Point of Confluence @ MH 11 0.06039 0.153 SSMH-11 333.45 237 8 0.002390 0.002613 332.83 SSMH-10 0.730
PIPE 2 SF 7 0.00281 4.768 0.227 SSMH-11 333.45 237 8 0.002390 0.002613 332.83 SSMH-10 0.730
PIPE 21 SF 10 0.00402 4.601 0.018 SSMH-28 336.15 318 6 0.003507 0.010000 332.96 SSMH-10 0.663
Point of Confluence @ MH 10 0.06722 0.245 SSMH-10 332.73 155 8 0.002390 0.002459 332.35 Boundary 0.708
PIPE 1 SF 0 0.00004 7.215 0.245 SSMH-10 332.73 155 8 0.002390 0.002459 332.35 Boundary 0.708
EXTENSION SF 206 0.08281 3.400 0.527 Boundary 332.35 1,866 8 0.002390 0.004315 324.30 TIE-IN 0.938
Point of Connection to Exist. 48" Sewer 26 0.15007 0.527 <<< Direct Flow into Exist. 48" on McCUTCHEN ROAD
NOTE: The Proposed Sewer Extension to Mccutchen Road collects Future Tract 7043 runoff which assumes 6,000 sq ft lots for a total area 28.33 acres. 28.33 acres/0.137741 ac per lot = Approx. Number of 206 Lots
EXISTING
SUMP
(NOT A PART)
PROPOSED
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