HomeMy WebLinkAbout17 - Design Report - Lakes at Valley West - Wastewater THE LAKES AT VALLEY WEST
PLANNED UNIT DEVELOPMENT
WASTEWATER DESIGN REPORT
NOVEMBER 17, 2014
REVISED 1UNE 7, 2016
REVISED MARCH 9, 2017
REVISED DECEMBER 11, 2017
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Contents
Introduction...........................................................................................................................................2
WastewaterFlows................................................................................................................................2
Infrastructure within the Boundaries of the Planned Unit Development..............................2
OffsiteInfrastructure...........................................................................................................................3
Phases1 and 2......................................................................................................................................3
Phase3 ...................................................................................................................................................4
Phase4...................................................................................................................................................4
Phase5 and 6........................................................................................................................................4
Summary................................................................................................................................................4
1
Introduction
The Lakes at Valley West Planned Unit Development was projected to have approximately 300
dwelling units and will be completed in multiple phases. Wastewater service will be provided by
the City of Bozeman through a combination of existing infrastructure and newly constructed
infrastructure primarily located within the boundary of the Planned Unit Development. The
purpose of this report is to identify the capacity of the existing system, conceptual improvements
for the Planned Unit Development and specific improvements required for the various phases of
the PUD.
Wastewater Flows
The full build out of the PUD was projected to have up to 300 dwelling units. Based on the City
of Bozeman Design Standards the total average daily wastewater flow will be 56,337 gallons
per day. (89 gpdpc x 2.11 people per unit x 300 units) In addition, based on the Design
Standards, the PUD will contribute 9,750 gpd of infiltration. (65 acres x 150 gpd/acre) The total
average daily flow is computed to be 66,087 gpd and the peak flow from the PUD is computed
to be 230,591 gpd based on a peaking factor of 3.92. (56,337 gpd x 3.92 +9,750 gpd)
Phase 1 and 2 consisted of 61 dwelling units, 5 accessory dwelling units, and 22.9 acres of
property.
Phase 3 adds 50 dwelling units, 4 accessory dwelling units, and 10.5 acres of property.
Phase 4 adds 25 dwelling units, 2 accessory dwelling units and 11.0 acres of property.
Phase 5 and 6 adds 79 dwelling units, 10 accessory dwelling units and 20.6 acres of property.
Summary Table of Units Submitted for Preliminary Plat
Phase Lots Accessory Dwelling Total Units
Units
1 and 2 61 5 66
3 50 4 54
4 25 1 2 27
5 and 6 79 1 10 89
1 Total 215 121 236
Infrastructure within the Boundaries of the Planned Unit Development
The existing wastewater infrastructure within the boundary of the PUD consists of an 8" main
stub located at the intersection of Westgate Avenue and Durston Road and a forcemain that
provides service to the Norton Lift Station located south of the PUD.
All wastewater from the PUD will gravity flow to the existing sewer main stub located at the
intersection of Westgate Avenue and Durston Road. The new infrastructure located within the
boundary of the PUD will include sewer mains and sewer services. The sewer mains will all be
8" in diameter and services will primarily be 4" in diameter. The actual sewer service sizes will
be determined during each phase based on the detailed layout developed during that phase of
the project.
The proposed 8" sewer mains will have a peak flow of 230,591 gpd (160.1 gpm). The capacity
of an 8" main at minimum slope (0.004 ft/ft) and flowing at 75% depth utilizing an n factor of
0.013 is 313 gpm. Thus the proposed 8" mains will have adequate capacity for all phases.
Offsite Infrastructure
Wastewater will flow from the PUD through sewer mains, a lift station and a forcemain
constructed as part of the Laurel Glen Subdivision located immediately to the north of the PUD.
The Laurel Glen forcemain discharges into a sewer main constructed by the original Valley
West Subdivision and flows from that point through interceptors to the City of Bozeman's Water
Reclamation Facility.
This existing offsite infrastructure has dedicated capacity of 49,088 gpd of wastewater flow on
an average day basis and an additional 6,600 gpd of infiltration capacity. These values are from
the design reports for the Laurel Glen Lift Station and are document in the memorandum
located in Appendix A.
This dedicated offsite capacity provides a total of 55,688 gpd average day flow capacity. For
The Lakes at Valley West PUD this will be utilized for 65 acres of infiltration capacity(9,750
gpd)with the remainder utilized for wastewater flow. Since the infiltration allowance is not
utilized with a peaking factor a review of the peak flow is required. The 49,088 gpd average day
wastewater flow equates to a peak flow of 166,899 gpd utilizing the peak factor of 3.40 that has
been established for the lift station. The allotted peak flow for wastewater is therefore 163,749
gpd. (166,899 gpd less additional infiltration requirement of 3,150 from the original allotment)
The resulting average day flow allotted for wastewater flow is therefore 48,161 gpd. The
available wastewater capacity is therefore 256 dwelling units based on 2.11 people/unit and 89
gpdpc.
Future improvements will be required to serve the PUD beyond the 256 dwelling units of
capacity that currently exist. A review of the available capacity of sewer mains between the
PUD and the Laurel Glen Lift Station has been completed and summarized in a memorandum
located in Appendix B. The memorandum documents adequate capacity to serve the PUD from
the point of connection to the lift station. Improvements to the lift station will most likely be
required when the PUD exceeds 256 dwelling units. Improvements downstream of the lift
station maybe required at that point. It is recommended as the PUD is developed that the
number of dwelling units be tracked. Depending on the actual number of dwelling units
eventually contemplated offsite infrastructure improvements may or may not be required.
Phases I and 2
The Lakes at Valley West, Phases 1 and 2 will be served by an 8" sewer main that begins at the
Intersection of Westgate Avenue and Durston Road, extends through future phases of the
Lakes at Valley West and contuse through the Phase 1 and 2 Subdivision to provide sewer
service to each lot within the development. Adequate capacity is available in the existing City of
Bozeman wastewater infrastructure and the proposed 8" mains will provide adequate capacity
for the development.
3
Phase 3
The Lakes at Valley West, Phase 3 will be served by an 8"sewer main that either was
constructed as part of Phases 1 and 2 or an 8" sewer main installed as part of Phase 3. The
wastewater flows down a sewer main in Westgate Gate Avenue to the north. Adequate
capacity is available in the existing City of Bozeman wastewater infrastructure and the proposed
8" mains will provide adequate capacity for the development.
Phase 4
The Lakes at Valley West, Phase 4 will be served by an 8" sewer main that either was
constructed as part of Phases 1 and 2 or 3 and an 8" sewer main installed as part of Phase 4.
The wastewater flows down a sewer main in Westgate Gate Avenue to the north. Adequate
capacity is available in the existing City of Bozeman wastewater infrastructure and the proposed
8" mains will provide adequate capacity for the development.
Phase 5 and 6
The Lakes at Valley West, Phase 5 and 6 will be served by an 8" sewer main that either was
constructed as part of Phases 1 and 2, 3 or 4 and an 8" sewer main installed as part of Phase 5.
The wastewater flows down a sewer main in Westgate Gate Avenue to the north. Adequate
capacity is available in the existing City of Bozeman wastewater infrastructure and the proposed
8" mains will provide adequate capacity for the development.
Summary
The existing City of Bozeman wastewater infrastructure in addition to the proposed 8" sewer
mains with the development will provide adequate capacity to serve 256 dwelling units in The
Lakes at Valley West Planned Unit Development. With the final phase of the project being
proposed at this time, only 236 dwelling units are included in the project. This is less than the
256 dwelling unit capacity of offsite facilities and therefore the project can be served by a
combination of existing facilities and newly installed 8" sewer mains within the boundary of
Phase 5 and 6.
Appendix A
MORRI ON
EFO MMENC. memo
An Emplqyee-(hIMny
TO: Greg Stratton
FROM: James Nickelson<�
1-4�
RE: Valley West Property (Wing Lakes)
Wastewater Capacity
DATE: February 27, 2014
As requested, we have reviewed documentation relative to wastewater collection
system capacity for the Valley West property located west of the Valley West Park. This
property consists of approximately 65 acres and consists of Tract 1 of Certificate of
Survey 1005B and Tract 2A of Certificate of Survey 1005C.
The following documents have been reviewed.
0 2003 Laurel Glen Subdivision Design Report by Allied Engineering
0 2002 Letter from Morrison Maierle to Allied Engineering
0 2006 Laurel Glen Lift Station Report by C & H Engineering
Based on this information it is our opinion that 49,088 gallons per day of wastewater
capacity (on an average day basis) is available to serve the Valley West property
through the Laurel Glen lift station and the Valley West Trunk Sewer Line downstream
of the lift station with no further improvements to these facilities.
Attachments: Excerpts from 2003 Laurel Glen Report
2002 Morrison Maierle Letter
Excerpts from 2006 Laurel Glen Lift Station Report
cc: City of Bozeman Engineering Division
LAUREL GLEN SUBDIVISION
LIFT STATION DESIGN REPORT
The Laurel Glen Subdivision is a 157-acre major subdivision consisting of both residential and
commercial zoned areas. The subdivision is located approximately 1300 feet west of the
intersection of Durston Road and Cottonwood Road in a portion of the south one-half of Section 4,
Township 2 South, Range 5 East. The lift station is to be designed to serve the development and
the portion of Valley West Subdivision to the south that cannot currently flow into the City's
collection system by gravity. A force main will connect the proposed subdivision with the Valley
West Gravity Trunk line.
The subdivision will be provided water and sewer service by the City of Bozeman, and all water
and sewer main extensions will be reviewed in accordance with certified check lists from the City
of Bozeman and the Montana Department of Environmental Quality. The homeowners will be
billed in their sewer rates for the City to assume the responsibility of operation and maintenance of
the lift station after it is constructed.
Laurel Glen Subdivision has been zoned, which is necessary to calculate the wastewater flow
projections. The peak hourly flow of the lift station was determined in accordance with City of
Bozeman design requirements, which in turn, are based on zoning classifications. The subdivision
will be developed in accordance with local subdivision regulations. The 1998 Wastewater Facility
Plan for the City of Bozeman, provides densities for persons per acre and a flow of 72 gpd/capita
to estimate flows. The breakdown of developed area and associated population densities are
estimated below in Table 1.
Table 1. Total Developed Area and Population Densities of Laurel Glen Subdivision
Total Area Population Density
Zone Classification Kacres) (people/acre)
R-2 34.74 7.62
R-3 32.56 12.19
R-3A 38.06 12.19
R-4 21,84 12.19
B-1 8.72
Park/Open Space 21.08
Total 157.0
The lift station will also service a 71 acre portion of the Valley West Subdivision. Morrison-
Maierle, Inc. has provided zoning for the Valley West Subdivision which will be used to calculate
the wastewater flow projections. There are 44 developed acres in this section, 40 identified for
R-3 zoning and four acres identified for B-1 zoning. The same densities used for Laurel Glen
Subdivision will be used to estimate flows.
MDEQ Project:L -85 Laurel Glen Subdivision
March 21,2003
The total population served by the lift station is estimated below in Table 2. The 1998 Wastewater
Facility Plan for the City of Bozeman did not provide for wastewater flows generated by the
Business Park zoning designation. The largest generator of wastewater per acre in the facility plan
was the B2 zoning designation at 3,495 gallons per acre,which was used in lieu of a flow for B-1.
Table 2. Population Served by Lift Station
Population Number of
Zone Classification (per acre) Developed Acres —Total Population Flow(gpd)
Laurel Glen
R-2 7.62 34.74 265 19,060
R-3 12.19 32.56 397.-1-28,578
R-3A 12.19 38.06 464 33,405
R-4 12.19 21.84 267 — 19,-169
B-1 N/A 8.72 30,477
Valley West
R-3 12.19 40 487.6 35,108
B-1 N/A 4 13,980
Totals 179.92 179,777
The average daily flow rate, including infiltration, is then calculated as follows:
179,777 gal/day/ 1440 min/day= 124-85 gpm
(150 gal/acre/day x 228 total acres)/ 1440 min/day=23.75gpm
124.85 gpm +23.75 gpm= 148.6 gpm
An equivalent population was estimated in order to calculate a peaking factor. According to the
1998 Wastewater Facility Plan for the City of Bozeman, people generate 72 gped. The total flow
of 179,777 gpd has an equivalent population of 2,497 people.
Using the following equation from DEQ2, the peaking factor for the peak hourly flow rate was
estimated as follows:
F=(18 +Po- )/(4+Po")
Where:
F=Peaking Factor
P =Population (in thousands)
F= (18 + 2.4"')/(4 + 2.40-')
F=3.52
P:00001007185 Laurel Glen SubDesign ReporhLiff SlaliontDe#gn Repon 3-21-03.doc
Allied Engineering Services,Inc. Page 2
MDEQ Project:,,- 185 Laurel Glen Subdivision
March 21, 2003
The peak hourly flow rate is then estimated to be 124.85 gal/min * 3.52 = 439.47 gal/min+ 23.75
gal/min (infiltration)= 463.22 gal/min. A peak hourly flow rate of 465gpm will be used for all
calculations.
The proposed lift station will consist of two identical submersible pumps and an auxiliary power
generator. The control panel and valves will be situated inside a building. The pumps are located
in the wet well which consists of a six foot diameter concrete manhole with a total inside depth of
approximately 20 feet. The pumps are sized to service the peak flow with the target pump out of
service, as per MDEQ requirements.
The pump discharge assemblies will be four-inch diameter. Inside the lift station enclosure, both
pumps discharge assemblies will be connected together with a four-inch discharge plug valve.
The force mains will then transition to eight-inch diameter PVC SDR 21 pipe, and will be
approximately 5300 feet in length until it discharges into the Valley West Trunk gravity sewer at
the intersection of Durston Road and Cottonwood Road.
Additional features of the lift station include:
Permanent standby engine;
4 Continuous monitoring by a SCADA system in the City of Bozeman shop.
Pump Sizing. DEQ 2 requires the lift station pumps to meet the peak hour demand with the
largest pump out of service. Since both pumps will be sized the same, each pump will need to
have a capacity of 465 gpm, DEQ 2 also requires use of the Hazen Williams equation to estimate
pipe friction (C value of 120). The pumps specified have a discharge of 465 gpm at 75 TDH.
The maximum total dynamic head for each pump is calculated as follows;
Friction: 1811. of 6" ductile iron @ 465 gpm, C=120 0.4 feet
530011 of 8" PVC @ 465 gpm, C=120 27.4 feet
Elevation: from LWL to discharge into gravity sewer 45.0 feet
Minor Losses: 2 -6"90 degree bends @ 465 gpm (K=.3) 0.2 feet
I - 6"gate valve @ 465 gpm (K= 1) 0.4 feet
I - 6" swing check valve @ 465 gpm(K= 1.5) 0.6 feet
1 - 6"tee @ 465 gpm (K=0.6) 0.2 feet
1 - 4"x 6"reducer @ 465 gpm (K=0.4) 0.2 feet
2— 8" 90 degree bends @ 465 gpm (K=0.3) 0.1 feet
Total Dynamic Head: 74.5 feet
The pump will be sized based on 75 feet of total dynamic head. The selected pumps are Gorman
Rupp Submersible JS4K60-X18 non-clog pumps,which can pass a 3.00 inch diameter solid.
PA2000100-185 Laurel Glen SubWesign ReportV ift StationlDesign Report 3-21-03.doc
Allied Engineering Services,Inc. Page 3
ENGINEERS
MORMSON SCIENTISTS
SURVEYORS
PNNERS
MMERLE,INC. 901 TECHNOLOGY BLVD P.O.BOX 1113 •BOZEMAN,MT 59771 • 406-587.0721 FAX:406LA-587-1176
An Employee-Owned Company
August 29, 2002
Josh McGibbon
Allied Engineering Services
32 Discovery Dr.
Bozeman, MT 59718
RE: Valley West Subdivision — Phases 7 & 8
Sewer and Water Service
MMI #3384.006
Dear Josh:
This letter is to address provisions for water and sewer service to be extended
across Durston Road to serve Phases 7 & 8 of the Valley West Subdivision. Per
our discussions on Friday, August 23, 2002, it is our understanding that as part of
the infrastructure improvements for the Laurel Glenn Subdivision the water and
sewer trunk systems will be extended in Durston Road to the West boundary of
the property, and that water and sewer piping will be stubbed to the Valley West
Property on the south side of Durston Road to the west of Bronken Park.
The Valley West Planned unit Development calls for the total acreage of Phases
7 & 8 to be 71 acres. Of this total there are 40 acres identified for residential
development generally at densities allowed by R-3 zoning in the City of Bozeman
Design Standards. Additionally there area 4 acres identified for commercial
development with a B-1 Zone Classification.
We hope that this provides the information you need to complete your design
work. If you need additional information please advise.
Thanks
Morrison-Maierle, Inc.
(fregAtrafton, P.E.
Project Engineer
H:X3384\006NDOC\Corresp,,Allied—August 29.doc
"Providinq resources in partnership with clients to achieve their goals"
DESIGN REPORT
FOR PROPOSED MODIFICATIONS
TO THE EXISTING LAUREL GLEN
LIFT STATION
(revised May 2006)
LAUREL GLEN SUBDIVISION
BOZEMAN, MT
Prepared for:
David Macdonald Construction, Inc.
2055 N. 22" Ave., Suite 4, Bozeman, MT 59718
and
Rosa Johnson Construction
PO Box 11113, Bozeman, MT 59719
Prepared by:
C & H Engineering and Surveying, Inc.
205 Edelweiss
Bozeman, MT 59718
(406) 587-1115 WIN I
P
C)
Project Number: 05189/05230
May, 2006
INTRODUCTION
This design report and calculations serve as an update to the Laurel Glen Lift Station and Valley
West Sanitary Sewer Trunk Main analysis approved in January, 2004 and the Proposal for Lift
Station Modifications (revised April 2005). Based on Allied Engineering's design report for
Laurel Glen Subdivision, the property currently served by the lift station, will produce an average
flow of 148.6 GPM including infiltration, The total population of both the Rosa Subdivision and
the Flanders Creek Subdivision was previously calculated as 832 people. The average flow to the
lift station from these two subdivisions including infiltration was previously calculated as 49.8
GPM. The total average flow to the lift station,based on the calculations previously submitted, is
198.4 GPM. A peaking factor of 3.4 was calculated based on the equation provided in the City of
Bozeman's Design Standards. Utilizing this peaking factor, the peak flow to the lift station will be
598.1 GPM including infiltration.
The existing lift station wet well is sized to handle the sewer flow from Laurel Glen and a portion
of Valley West. In order for both Flanders Creek Subdivision and Rosa Subdivision to utilize this
wet well, additional capacity would be required. The existing wet well elevation is such that both
the Flanders Creek Subdivision and Rosa Subdivision could not utilize the existing wet well
unless it was lowered. C&H Engineering is proposing the construction of a new wet well, sized to
handle all sewer flows from the Laurel Glen Subdivision, a portion of the Valley West
Subdivision,Rosa Subdivision and Flanders Creek Subdivision. The pumps installed in this new
wet well will be sized to handle the peak flows of all of the combined subdivisions. The existing
wet well will then be abandoned once the construction of the new wet well is complete. The new
pumps will be connected to the existing control building in order to utilize the existing piping,
valves and also the existing control panel and backup 50 kW generator.
PUMP CALCULATIONS
The additional flow into the Laurel Glen Lift Station is based on the proposed zoning of C.O.S.
2389 and a revised peaking factor for the entire population which would flow to the lift station.
C.O.S. 2389 is 78.76 acres. In order to verify the capacity modeling,the approved lot layout was
used to determine the maximum number of lots/people which could be built. Please see the
attached plat map and the chart below which calculates the proposed population of the property.
POPULATION CALCULATIONS
FLANDERS MILL & ROSA SUBDIVISION
FLANDERS MILL SUBDIVISION
BLOCK# # UNITS #People
1 2.7198 acres 33.18
2 14 lots 14 35.56
3 14 lots 14 35.56
4 32 lots 32 81.28
5 6.8889 acres 84.04
6 40 lots 40 101.60
Total # People
(Flanders) = 371.23
ROSA SUBDIVISION
BLOCK # DESCRIPTION #UNITS #People
1 19 lots 19 48.26
2 18 lots 27 68.58
3 17 lots 18 45.72
4 46 lots 46 116.84
5 2,7024 acres 32.97
6 3.6481 acres 44.51
7 4 lots 8 20.32
1.0331 acres 12.60
8 9 lots 21 53.34
9 4 lots 4 10.16
0.5710 acres 6.97
Total# People
(Rosa) = 460,27
C.O.S. 2389 Population: 832 people
Allied Engineering's design report for Laurel Glen Subdivision states that the equivalent
population of the land currently served by the lift station is 2,497 people (some assumptions were
made for B-1 zoning). This results in a total population of 3,3 29 people utilizing the lift station.
Averaize Flow
Allied Engineering's design report for Laurel Glen Subdivision states that the area currently
served by the lift station will produce an average flow of 148.6 GPM including infiltration.
Average flows from C.0,S. 2389 are calculated below using,72 GPD per capita and 150 GPD per
acre of land.
Average flow: 832 people 72 GPD per capita=59,904 GPD = 41.6 GPM
78.76 acres 150 GPD/acre= 11,813.3 GPD=8.2 GPM (Infiltration)
C.O.S.2389 Average Flow =71,717.3 GPD=49.8 GPM
Total Average Flow to Lift Station = 148.6 GPM +49.8 GPM= 198.4 GPM
(Dec. 2003 original estimate= 204.8 GPM)
Peak Flow
Based on a total population of 3,329 a revised peaking factor is calculated based on the equation
provided in the City of Bozeman's Design Standards.
Qmax 18+PJ/2
------- --------- (P =Population in thousands)
Qave 4+P 1/2
Peaking Factor=3.40
Average flow without infiltration for C.O.S. 2389 is 41.6 GPM and for Laurel Glen is 124.9 GPM
(from Allied's report). Applying the peaking factor and infiltration results in a peak flow as
follows.
Flows: 41.6 GPM+ 124.9 GPM= 166.5 GPM
166.5 GPM * 3.40= 566.1 GPM
C.O.S. 2389 is 78.76 acres and Allied's report states that the lift station is designed for the 157
acre subdivision (Laurel Glen)in addition to 71 acres of Valley West(228 acres total).
Infiltration- 78.76 acres +228 acres=306-76 acres
306.76 acres * 150 GPD/acre=46,014 GPD=32.0 GPM
Total Peak ,Flow to lift Station = 32.0 GPM+ 566.1 GPM= S98.1 GPM
(Dec. 2003 original estimate = 618.1 GPM)
Pump Sizing
Pump sizing was completed using a combination of Watercad and Flygt Pump software. At this
point in the design process it was assumed that Flygt pumps would be used since they are currently
installed in the existing lift station. Two pumps will be installed in the new wet well, with each
pump being able to handle the peak flow of 598.1 GPM. The new wet well will have an (8) foot
inside diameter to allow for the additional flows and also keep the wet well as shallow as
possible due to the high ground water at the project site.
Due to the size of the force main, and the Hazen-Williams friction coefficient "C"which is
required to be 120 by DEQ-2, each pump will be capable of pumping 620 GPM, Pump Curves for
the proposed Flygt Pumps are included. The proposed pumps are Flygt pumps NP3171.180 with a
270 nim diameter impeller and a 230V, 60 HZ, 3-phase motor.
The new wet well will be set at the elevations shown on the design drawings. The level
transducer control settings will result in a depth of three feet available for filling.
A Watercad model was utilized to select the pumps required to handle the maximum flow with one
pump out of service. The pumps were set at an elevation of 4697.40, along with the outlet to the
Valley West gravity system at the intersection of Cottonwood and Durston Roads (4744.65).
Elevation headloss is 47.25 feet. The Watercad analysis for one pump running and two pumps
running are attached.
With: one pump operating, the flow through the force main with friction and Tread losses,
which total 94.77 feet,will be 620 GPM. With two pumps operating, the flow through the
force main with friction and head losses, which total 109.89 feet, will be 739 GPM,
Cycle Times
Cycle times were analyzed for average flows and peak flows. During average flows only one
Appendix B
MORRISON
DOI MAIK Company
memo
An Employee
TO: Greg Stratton
FROM: Jodie Binger and James Nickelson
RE: Valley West— Wing Lake Property
Existing Sewer Capacity Through Laurel Glen Subdivision to Lift Station
DATE: March 17, 2014
The existing 8" and 10" sewer mains within the Laurel Glen Subdivision were analyzed
to determine if the mains have adequate capacity to convey expected flows from the
proposed Valley West Subdivision. Existing flow was determined based on currently
built units and zoning classifications. Expected flow was determined based on the City
of Bozeman Design Standards. Both of the existing line sizes were shown to have the
capacity to include the proposed flows. Flow calculations and Figures are attached to
support these findings.
Based on a maximum number of units of 300 on the Valley West property the expected
flow from Valley West is 0.36 CFS. After build out of the Laurel Glen Subdivision, the 8"
outfall line has 0.61 cfs of capacity and the 10" outfall line has 0.71 cfs of capacity.
Thus adequate capacity exists to serve Valley West through these sewer mains.
Attachments:8" Calculations with Supporting Map
10" Calculations with Supporting Map
Record Drawings of Laurel Glen Sewer
Existing Flow in 8"Laurel Glen Sewer Line
Services 145.33 units
People 2.11 people
units
Flow 89 gal
person day
131 zoning 6.53 acres
1000 gal
acre day
Infiltration 150 gal
acre day
Area 33.32 acres
Wastewater Flow(based on asbilts and plat)
average flow: 145.33 units I 2.11 people I 89 gal 27292 gal
(units) units person day day
average flow: 6.53 acres 1000 gal I 6530 gal
(B1) acre day day
population: 145.33 units I 2.11 people 307 people
units -
0.31 people in thousands
peak flow: (18+PA.5) 18.5537565 4.07 peaking factor
(4+PA.5) 4.55375653
4.0743851 33821.521 gal 137802 gal
day - day
infiltration: 150 gal 33.316791 acres 4998 gal
acre day day
total flow 137801.9 gal + I 4997.5186 gal I 142799 gal
day day day
99 gal
min
0.22 cfs
Laurel Glen Pipe Flow Conditions
pipe flow(assume greater than 1/2 full) pipe flow(assume less than 1/2 full)
d 8in d 8in
n 0.013 n 0.013
k 1.486 k 1.486
s 0.003 ft/ft s 0.003 ft/ft
r 0.333 ft r 0.333 ft
h 0.402 ft h 0.265 ft
theta 3.557 rad theta 2.727 rad
A 0.129 ftA2 A 0.129 ftA2
P 0.909 ft P 0.909 ft
R 0.142 ft R 0.142 ft
q 0.22 cfs q 0.22 cfs
flow<1/2
Note:h>r therefore less than 1/2 full
Allowable Future Flow(75%pipe full flow)
pipe flow
d 8 in
n 0.013
k 1.486
s 0.003 ft/ft
r 0.333 ft
h 0.167 ft
theta 2.094 rad
A 0.281 ftA2
P 1.396 ft
R 0.201 ft
q 0.60 cfs
Q(allow from 0.38 cfs
Valley West)
172 gal
min
Flow Expected From Valley West Proposed
Services 300 services
People 2.11 people
service
Flow 89 gal
person day
Infiltration 150 gal
acre day
Area 65 acres
Wastewater Flow(based on proposed Valley West Subdivision)
average flow: 300 services 2.11 people 89 gal - 56337 gal
service person day day
population: 300 services 2.11 people 633 people
service
0.63 people in thousands
peak flow: (18+PA.5) 18.795613 3.92 peaking factor
(4+PA.5) 4.79561297
3.9193351 56337 gal 220804 gal
day day
infiltration: 150 gal 65 acres - 9750 gal
acre day day
total flow 220803.6 gal + 9750 gal 230554 gal
day day day
160 gal
min
0.36 cfs
Existing Line WILL Convey Flow From Proposed Valley West Addition
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Existing Flow in 10"Laurel Glen Sewer Line(phase 1 and 2)
Services 443.67 services
People 2.11 people
service
Flow 89 gal
person day
81 zoning 6.53 acres
1000 gal
acre day
Infiltration 150 gal
acre day
Area 68.76 acres
Wastewater Flow(based on asbilts and plat)
average flow: 443.67 services 2.11 people 89 gal 83317 gal
I service person day day
average flow: 6.53 acres 1000 gal _ - 6530 gal
(B1) acre day day
population: 443.67 services 2.11 people 936 people
service
0.94 people in thousands
peak flow: (18+PA.5) 18,9675452 3.82 peaking factor
(4+PA.5) 4,96754519
3.818293 89846.789 gal 343061 gal
day day
infiltration: 150 gal 68,76322 acre 10314 gal
acre day day
total flow 343061.4 gal + 10314.483 gal 353376 gal
day 1 day----] day
245 gal
min
0.55 cfs
pipe flow(assume greater than 1/2 full) pipe flow(assume less than 1/2 full)
d 10in d 10in
n 0.013 n 0.013
k 1.486 k 1.486
s 0.004 ft/ft s 0.004 ft/ft
r 0.417 ft r 0.417 ft
h 0.467 ft h 0.366 ft
theta 3.385 rad theta 2.898 rad
A 0.231 ftA2 A 0.231 ftA2
P 1.208 ft P 1.208 ft
R 0.191ft R 0.191ft
q 0.55 cfs q 0.55 cfs
flow<1/2
Note:h>r therefore less than 1/2 full
Allowable Future Flow(75%pipe full flow)
pipe flow
d 10 in
n 0.013
k 1.486
s 0.004 ft/ft
r 0.417 ft
In 0.208 ft
theta 2.094 rad
A 0.439 ftA2
P 1.745 ft
R 0.251 ft
q 1.26 cfs
Q(allow from 0.71 cfs
Valley West)
318 gal
min
Flow Expected From Valley West Proposed
Services 300 services
People 2.11 people
service
Flow 89 gal
person day
Infiltration 150 gal
acre day
Area 65 acres
Wastewater Flow(based on proposed Valley West Subdivision)
average flow: 300 services I 2.11 people I 89 gal 56337 gal
service person day I day
population: 300 services I 2.11 people 633 people
it service
0.63 people in thousands
peak flow: (18+PA.5) 18.795613 3.92 peaking factor
(4+PA.5) 4.79561297
3.9193351 56337 gal 220804 gal
day day
infiltration: 150 gal 65 acres 9750 gal
acre day 1 day
total flow 220803.6 gal I + I 9750 gal I 230554 gal
day day I day
160 gal
min
0.36 cfs
Existing Line WILL Convey Flow From Proposed Valley West Addition
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