HomeMy WebLinkAbout08 - Design Report - West Winds Ph 4 - Stormwater 71�/C)
Stormwater Investigation
For
West Winds Planned Community
Phase 4
Prepared By:
HKM Engineering Inc.
920 Technology Blvd. Suite A
Bozeman, MT 59718
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Revised
July 8, 2008
04S067.125
Stormwater Investigation
For
West Winds Planned Community
Phase 4 Subdivision
Prepared For:
Cascade Development, Inc.
1627 West Main St.
Bozeman, MT 59715
Prepared By:
HKM Engineering Inc.
920 Technology Blvd., Ste. A
Bozeman, MT 59718
Revised
July 8, 2008
04S067.125
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Phase 4: Stormwater InveSLigation Report June 2008
Table of Contents
Page
Purpose............................................................................................................................................ 2
ProjectOverview ............................................................................................................................ 2
Preliminary Conditions Summary................................................................................................... 2
Basisof Calculations....................................................................................................................... 3
StormwaterDetention..................................................................................................................... 3
Stormwater Treatment and Release................................................................................................ 6
ConveyanceFacilities..................................................................................................................... 6
Maintenance.................................................................................................................................... 7
Conclusion...................................................................................................................................... 8
Table 1 —Peak Runoff& Required Storage Volumes.................................................................... 3
Table 2— Stormwater Pond Summary............................................................................................ 5
Table 3 — Storm Sewer Capacity Calculations ............................................................................... 7
Figure 1 —Phase 4 Stormwater Plan............................................................................................... 2
Figure 2— Stormwater Pond Section A:A......................................................................................3
Figure 3 — Stormwater Drainage Basins.........................................................................................3
Appendices
Appendix A—Detention Pond Volume Calculations
Appendix B —Conveyance Facility Calculations
Appendix C—Outlet Orifice Sizing
Page 1 of 7
[NGINECAIN�
Phase 4: Stormwater Investigation Report June 2008
Purpose
This engineer's report is intended to address the stormwater management system for the
proposed Phase 4 Subdivision of the West Winds Planned Community, and will supplement the
Stormwater Investigation Report submitted with the P.U.D Application. The southern 650 feet of
Winward Avenue included within Phase 4 was previously permitted and constructed. The
stormwater management system for this portion of Winward Ave. will connect to the proposed
stormwater management system within Phase 4— as a whole—in order to enable conveyance of
the stormwater runoff to the detention facilities. This report supplements the Winward Avenue
Stormwater Investigation previously submitted, and will determine the recommended sizing of
the stormwater detention basins and conveyance facilities within the Phase 4 subdivision. This
report was prepared in accordance with the design criteria set forth in the City of Bozeman's
Design Standards and Specifications Policy.
Pro 6ect Overview
The Phase 4 Subdivision of the West Winds Planned Community contains four large lots that
will contain an assisted living facility with approximately 68 units for senior citizens and a
retirement villa community with approximately 48 units. Phase 4 also contains five single-family
lots (see Figure 1). Phase 4 is located in the southwest portion of the West Winds Planned
Community, which is located in the northeast '/ of the northwest %, Section 2, Township 2
South, Range 5 East. Phase 4 is bordered by Oak Street on the south, Phases 2A and 3 of West
Winds Park on the east, future Phases 5 and 6 on the north, and Phase 5 on the west.
Preliminary Conditions Summary
The pre-development condition of the proposed 17.03-acre subdivision is agricultural with no
residential structures on site. The property is currently being used for hay production. The site
is not currently irrigated, but the property has water rights through the Farmer's Canal Ditch
Company a/k/a Harmon Ditch. The current topography of the site can be generalized as flat with
a consistent slope of approximately 2% from south to north. There is a seasonal watercourse that
runs adjacent to the east side of the subject parcel running south to north. This watercourse is a
continuation of the Harvest Creek linear park to the south and is within the open space on the
preliminary plat of Baxter Square Subdivision to the north.
The NRCS Soil Survey has identified three soil types on the property: Amsterdam silt loam
(53B); Meadowcreek loam (510B); and Fairway silt loam (511A). These soil types correlate to
the SCS Hydrologic Soil Group "B". Soil pits were excavated and groundwater monitors were
installed in April 2003 and monitored through September 2003. From these pits and subsequent
pits excavated in April of this year, it was determined that the soil horizon is typical of the
Bozeman area with approximately 12" to 18" of topsoil underlain with a layer of silty-clay,
followed by sandy gravel. The groundwater depth varied dependant on elevation and proximity
to irrigation channels with a typical minimum depth to water being in the range of 4' to 8' below
ground surface within proposed housing areas.
Page 2 of 7
E N G I N E E R I N�
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PROPOSED TRAIL SYSTEM
PROPOSED LOT UNE GALLA TIN COUNTY, MONTANA
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Phase 4: Stormwater Invescigation Report June 2008
Basis of Calculations
The calculations and recommendations within this report are based on the regulations set forth in
the City of Bozeman Design Standards and Specifications Policy. The Rational Method was
used to determine the pre-developed release rates and, in turn, the post-developed minimum
required storage volumes. All calculations associated with the release rates and required storage
volumes were based on a 10-year, 2-hour storm event. The conveyance facilities, described
further in this report, are based on a 25-year, 2-hour storm event. Calculations are provided in
the appendices of this report.
Stormwater Detention
The Phase 4 area originally comprised of two drainage basins identified as B-6A and B-6B in the
West Winds Final PUD Application. Subsequently, more detailed topographic surveys have
been performed and the phasing boundary lines for the project have been revised. Therefore, the
original drainage basin boundaries have also been revised. There are a total of five drainage
basins within the revised Phase 4 subdivision boundary, Basins 4A through 4E (see Figure 3).
There are two drainage basins located within previous Phase 3 (Basins 3A and 3B) and two
basins within future Phase 5 (Basins 5A and 5B) of the overall West Winds development whose
run-off will also be conveyed to the detention ponds by the Phase 4 storm water system. The
drainage basins are described in further detail below. A summary of the pre-developed peak
runoff rates and the post-developed required storage is shown in Table 1. The proposed
temporary detention ponds are shown in Figures 1 and 3, and a typical cross-section of the
temporary detention facilities is shown in Figure 2.
Table 1 —Peak Runoff& Rec tired Storage Volumes
Detention/Retention Contributing Pre-Developed in. Required Storage
Pond Basins Peak Runoff Rate
(Cfs) (Cf)
Pond 1 3A, 4A through 4D, 5A & 5B 3.95 19,640
Pond 2 3B &4E 2.23 11,386
Pond 3 4C &5A N/A 18,677
Stormwater runoff from Basins 4C and 5A will initially be conveyed to temporary Retention
Pond 3 located east of Phase 4 within future Phase 5, for storage. Once the plans for the
development within these basins are finalized, Retention Pond 3 may be removed and runoff
from the basins conveyed through Basin 4D to Detention Pond 1 via the Phase 4 stormwater
system. Therefore, the stormwater conveyance system on Winter Park Street (storm Mains L-1
and L-2), Winward Avenue (Main L-3) and Detention Pond 1 have been sized to convey/store
the additional flows.
Basin 4A is a total of 0.88 acres in size and includes a portion of a retirement community lot.
The retirement community lots are estimated to house a total of 48 senior living dwellings in
Page 3 of 7
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FIGURE 3
200 0 200 400 WEST WINDS SUBDIVISION PHASE 4
scale feet STORM WATER DRAINAGE BASINS
Ck BOZEMAN, MONTANA J 04S067.125 JULY 8, 2008
Copyright 0 2008 HKM Engineering, All Rights Reserved.
Phase 4: Stormwater Investigation Report June 2008
Phase 4. The retirement community areas have an estimated C-factor of 0.6. Storm water from
this basin will be conveyed to Windward Ave. and transferred to a temporary detention pond via
curb and gutter, storm piping and temporary swale. Temporary Detention Pond 1 will be located
on the north end of Windward Ave. within the future Phase 6 Subdivision. Upon final build-out,
temporary Pond 1 will be removed and the storm water will be conveyed to permanent detention
ponds near Baxter Lane.
Basin 4B is a total of 0.62 acres in size and includes a portion of two retirement community lots.
The retirement community areas have an estimated C-factor of 0.6. Storm water from this basin
will be conveyed to Windward Ave. and transferred to temporary Detention Pond 1 via curb and
gutter, storm piping and temporary swale
Basin 4C is a total of 5.23 acres in size and includes portions of two retirement community lots
and 470 feet of Breeze Lane. The retirement community areas have an estimated C-factor of 0.6
and the road right-of—way was calculated to be impervious with a C-factor of 0.9. Storm water
Wilf be convey out to Breeze Lane and then transferred to a temporary retention pond via
curb and gutter an s orm piping. Temporary Retention Pond 1 will be located northwest of
proposed Breeze Lane within future Phase 5 of the proposed Subdivision (See Figure 3). Upon
development of the retirement community lots, Retention Pond 3 may or may not be removed as
discussed above.
Basin 4D is a total of 6.14 acres in size and includes one retirement community lot, 1.18 acres of
an assisted living lot, 0.21 acres of park area, 450 feet of Winter Park Street and 450 feet of
Winward Ave. The retirement community and assisted living areas have an estimated C-factor of
0.6, the park area has a C-factor of 0.2 and the road rights-of—ways have been calculated to be
impervious with a C-factor of 0.9. Stormwater will be conveyed to Winter Park Street and
Windward Ave. and transferred to temporary Detention Pond 1 via curb and gutter, storm piping
and temporary swale
Basin 4E is 4.16 acres in size and includes 5 single-family lots, 2.33 acres of an assisted living
lot, 434 feet of Hunters Way and 0.39 acres of park area. The single-family areas have an
estimated C-factor of 0.5, the assisted living areas have a C-factor of 0.6, the park area has a C-
factor of 0.2 and the road right-of—ways have been calculated to be impervious with a C-factor
of 0.9. Stormwater will flow to Hunters Way and be conveyed via curb and gutter, storm piping
and temporary swale to temporary Detention Pond 2 located on the north end of Hunters Way in
the future Phase 6 Subdivision. Upon final build-out, temporary Pond 2 will be removed and the
stormwater will be conveyed to permanent detention ponds near Baxter Lane.
Basin 3A is a portion of existing Phase 3 of the West Winds Development and is 1.99 acres in
size. Basin 3A includes 0.95 acres of independent senior living, 660 feet of Winward Ave. and
132 feet of Breeze Lane. Runoff from the independent living areas was calculated using a C-
factor of 0.6 and from the roadway rights-of-ways using a C-factor of 0.9. Runoff from the
development will flow to Winward Ave. and Breeze Lane and will be conveyed to Basin 4D via
curb and gutter and storm pipe. Runoff will then be conveyed via the storm sewer system within
Basin 4D to temporary Pond 1 for detention.
Page 4 of 7
"GI E E R I NG.
Phase 4: Stormwater Investigation Report June 2008
Basin 3B is a portion of existing Phase 3 of the West Winds Development and is 9.46 acres in
size. Basin 3B includes 8 single-family lots, 6.39 acres of independent senior living, 0.38 acres
of open space/park area, 784 feet of Hunters Way and 132 feet of Breeze Lane. The single-
family areas have an estimated C-factor of 0.5, the independent senior living areas have an
estimated C-factor of 0.6, the open space/park areas have a C-factor of 0.2 and the road rights-of
—ways have been calculated to be impervious with a C-factor of 0.9. Runoff from the
development will flow to Hunters Way and Breeze Lane and will be conveyed to Basin 4E via
curb and gutter and storm pipe. Runoff will then be conveyed via the storm sewer system within
Basin 4E to temporary Pond 2 for detention.
Basin 5A is a portion of the future Phase 5 West Wind Development and is a total of 4.78 acres
in size. The basin includes one future retirement community lots and 320 feet of Breeze Lane.
The retirement community area has an estimated C-factor of 0.6 and the road right-of—way has
been calculated to be impervious with a C-factor of 0.9. Storm water will flow to future Breeze
Lane, at which point it will be conveyed via curb and gutter and storm pipe to Retention Pond 3
located within future Phase 5.
Basin 5B is a portion of the future Phase 5 West Wind Development and is a total of 2.87 acres
in size. The basin includes one future retirement community lot and 310 feet of Winter Park
Street. The retirement community area has an estimated C-factor of 0.6 and the road right-of—
way has been calculated to be impervious with a C-factor of 0.9. Storm water will flow to future
Winter Park Street at which point it will be conveyed via curb and gutter and storm pipe to Basin
4D. The flows will then be conveyed via the storm sewer system located within Basin 4D to
temporary Pond 1 for detention.
Stormwater runoff from a portion of existing Oak Street and future Davis Lanes will be
conveyed via the future stormwater management facilities of Davis Lane north to the future
stormwater detention ponds located within the West Winds Development, adjacent to Baxter
Lane, as identified in Figure 1. No storm runoff from these roadways will outfall to the Phase 4
or 5 Subdivision development areas.
Table 2 below provides a summary of the proposed stormwater detention and retention ponds
including required storage, the storage volume at a depth of 1-1/Z feet, and an overall depth of 2 1/z
feet. The detention ponds volumes were calculated using the average end area method and are
based on the pond geometry shown in Figure 2. The detention ponds have been designed with
adequate inlet protection by means of riprap pads as to avoid erosion. The temporary detention
and retention ponds have been sized to detain stormwater runoff from Phases 3, 4 and portions of
Phase 5 Subdivisions,
Table 2—Stormwater Pond Summary
Pond WSE Storage Overall Storage Required Storage
Volume Volume Volume
(cf) (cf) (cf)
Pond 1 20,578 37,046 19,640
Pond 2 11,445 21,185 11,386
Pond 3 18,774 33,935 18,677
Page 5 of 7
E N G I N E E R N�
Phase 4: Stormwater InveS«gation Report June 2008
Stormwater Treatment and Release
The stormwater detention ponds have been designed for the removal of solids, silt, oils, grease,
and other pollutants. The pond has been sized to provide adequate volume and detention time to
allow the settling of solids, silts and other contaminants. The detention pond will use natural
vegetation to limit pollutants.
Stormwater will be released from the detention ponds at a rate equal to that of the 10-year pre-
developed storm event. Release will be accomplished through a flow control manhole equipped
with an orifice outlet. Discharge structure design is primarily driven by elevation and head,
which requires site-specific designs for each detention pond. Detailed pond sizing calculations
are provided in Appendix A and outlet orifice sizing calculations in Appendix C of this report.
Stormwater will be released from each detention pond into the Harmon Ditch. The flow control
manholes will be located at the ponds. Released stormwater will be conveyed to the Harmon
Ditch by means of manmade temporary drainage swales.
Conveyance Facilities
Stormwater runoff from this site will eventually be conveyed to stormwater detention ponds at
the north end of the Planned Community, adjacent to Baxter Lane shown in Figure 1. The storm
sewer infrastructure to the aforementioned ponds will be installed in future phases, and therefore
temporary stormwater detention ponds will be constructed at the north end of the Phase 4 and 5
Subdivisions. The temporary detention ponds will be abandoned and reclaimed when
subsequent storm drainage improvements are installed. The retention pond located within future
Phase 5 may or may not be removed in the future depending on final development configuration.
Detention Pond 1 has been designed to store the additional flows should Retention Pond 3 be
removed.
Stormwater will be conveyed by means of curb and gutter, catch basins, storm mains and
temporary swales. All conveyance facilities on the site have been sized to handle the 25-year, 2-
hour storm event as required in the City of Bozeman Design Standards and Specifications Policy.
Table 3 summarizes the post-developed runoff rates and required pipe diameters. The storm
sewer mains are shown graphically on Figures 1 and 3.
Storm sewer Mains L-1 and L-2 service Basins 4D and 5B. Mains L-1 and L-2 have been sized
to also service Basins 4C and 5A should Retention Pond 3 be removed in the future. Main L-3
services Basins 4A, 4B and 3A. Main L-4 services Basins 4A, 4B, 3A and portions of Basin 4D.
Storm sewer Main L-5 services Basins 3A, 4A, 4B, 4D and 5B. Main L-5 has been sized to also
service basins 4C and 5A if required in the future. Storm Mains L-6, L-7 and L-8 service Basins
3B and 4E. Main L-9 services Basins 4C and 5A. These 18" through 27" PVC storm mains
collect and convey the stormwater from Phases 3, 4, and a portion of Phase 5 Subdivisions to the
temporary detention/retention facilities, as noted below in Table 3. The gutter capacities, leaving
Page 6 of 7
E N G
Phase 4: Stonnwater Inves«gation Report June 2008
0.15' of freeboard on the face of curb, were found to be adequate for handling the stormwater
flows on all roadways. See Appendix B for detailed calculations.
Standard 24"x 36" square storm drain inlets and 48" and 60" combination manhole and curb
inlets (C.O.B Standard Drawing No. 02720-1 and 027204B, respectively) will be used to
capture the stormwater runoff at the points specified on Figure 3. These catch basins are in
conformance with City of Bozeman design standards and include a 9" sump for ease of
maintenance.
Table 3- Storm Sewer Capacity Calculations
Storm Sewer Post-D Rate cfeveloped Pipe Pipe Outfail
Main Runoff s Diameter in. Ca acit cfs Pond
L-1 14.41 27 19.59 Pond 1
L-2 14.88 27 19.59 Pond 1
L-3 4.57 18 6.64 Pond 1
L-4 5.30 18 13.70 Pond 1
L-5 18.93 27 19.59 Pond 1
L-6 9.83 18 11.98 Pond 2
L-7 11.67 21 15.03 Pond 2
L-8 12.55 21 15.03 Pond 2
L-9 9.17 18 10.50 Pond 3
Maintenance
The storm drainage system within the Phase 4 Subdivision is defined as a private and public
system. The mains and catch basins that lie within the publicly dedicated right-of-ways are
defined as public systems. The public systems shall be maintained by the City of Bozeman. The
private system, those facilities that do not lie within the publicly dedicated right-of-ways, will
initially be maintained by the developer and then the Homeowners Association.
Due to sediment in the storm runoff and other variables, regular maintenance will be required to
maintain proper performance of the storage and drainage network. The following steps are
minimum requirements for the maintenance of the storm facilities.
A) Inspection Program—On an annual basis, the following elements of the storm water
facilities should be inspected for excessive sediment deposits:
1) Catch Basins
2) Curb Cut Openings
3) Storm Mains
4) Detention Ponds
B) Maintenance Program—The following maintenance measures should be completed
based on the inspection program:
Page 7 of 7
"GI E E R IE E R I N�
Susan Stodola
From: Lowe, Zach [ZLowe@hkminc.com]
Sent: Thursday, July 10, 2008 8:58 AM
To: Susan Stodola
Cc: Smith, Walter; Litle, Clint
Subject: West Winds Ph4 Stormwater issues
Sue,
Per our conversation yesterday afternoon, we looked into our inspector's as-built drawings and confirmed in the field, that
the lateral storm line crossing Windward at its current north end is (as planned) a 15" line.
Because of initial assumptions in our original Windward Avenue storm report, the line north of Breeze Lane within
Windward was sized as a 21" line, however, due to more detail topographic surveys and the adjustment of phase
boundaries, we are now only collecting 31% of the area we previously had anticipated collecting at Breeze Lane(a 69%
reduction). The majority of the stormwater will be collected on site within the Epcon development and will connect into the
Winter Park storm line. In the Epcon preliminary site plan, a pond was proposed that would also receive collected
stormwater and would further reduce the required capacity of the storm mains within City ROW.
Please let me know how you would like us to proceed, as we feel the mains as proposed in our latest stormwater report
are adequately sized; otherwise we could up-size/over-size the storm main within Windward (north of Breeze) from 18"to
21"—whatever we need to get this report approved.
I will be out of the office quite a bit today, so if you cannot get a hold of me, please contact either Clint or Walt. Thanks.
Zach Lowe, P.E.
HKM Engineering
A Division of DOWL, LLC
920 Technology Blvd, Suite A
Bozeman, MT 59718
406.586.8834 (phone)
406.586.1730 (fax)
i
Susan Stodola
From: Lowe, Zach [ZLowe@hkminc.com]
Sent: Wednesday, July 09, 2008 2:53 PM
To: Susan Stodola
Subject: FW: West Winds Phase 4 -Stormwater Report
Sue,
Please find a response to the gutter capacity issue below.
Zach Lowe, P.E.
HKM Engineering
A Division of DOWL, LLC
920 Technology Blvd, Suite A
Bozeman, MT 59718
406.586.8834 (phone)
406.586.1730 (fax)
From: Smith, Walter
Sent: Wednesday, July 09, 2008 8:46 AM
To: Lowe, Zach
Subject: RE: West Winds Phase 4 - Stormwater Report
Correct. The gutter spreadsheet accounts for only the surface flow which is anticipated to reach the gutter. The
portion of gutter expected to receive the largest amount of flows (worst case) in each roadway segment was
considered. The balance of the stormwater runoff from the individual lot developments not accounted for on the
spreadsheet will be conveyed via the storm drain system. HKM Engineering has been involved in the
preliminary engineering for the individual developments adjacent to the roadways located within the
subdivision. Preliminary design information was used to determine the runoff quantities utilized on the gutter
capacity spreadsheet included in the stormwater report. This same information was used to size the storm pipe
mains within the subdivision to adequately convey the balance of the stormwater flows.
Should you have any questions or require further information, please give me a call.
Sincerely,
Walter R. Smith,P.E.
M
ENOINEERINO
920 Technology Blvd.,Ste.A
Bozeman,MT 59718
(406)586-8834 x539
(406)586-1730 fax
From: Brian Heaston [mailto:bheaston @BOZEMAN.NET]
Sent: Tuesday, July 08, 2008 5:02 PM
To: Lowe, Zach
Cc: Susan Stodola
Subject: RE: West Winds Phase 4 - Stormwater Report
Zach,
I'm not following the gutter spreadsheet. I'll use one pipe segment as an example. Table-3, sheet 7, shows post-
developed runoff for pipe L-9 at 9.17 cfs. The max gutter capacity calculated at the design slope for Breeze is 4.91 cfs.
The gutter capacity column, second from right end, looks to be mostly road area,with a small amount of lot area
contributing. Where is the rest of the runoff accounted for? Does it not reach the gutter? Are you placing the
responsibility on the lot developers to tie into the storm drain stub, so their runoff doesn't hit gutter?
Further detail on your methodology would be appreciated. Thanks.
Sincerely,
Brian Heaston,P.E.
Project Engineer
City of Bozeman - Engineering
20 E. Olive St.
P.O. Box 1230
Bozeman, MT 59771
(406) 582-2280
bheaston@bozeman.net
From: Susan Stodola
Sent: Tuesday, July 08, 2008 4:42 PM
To: Brian Heaston
Subject: FW: West Winds Phase 4 - Stormwater Report
From: Lowe, Zach [mailto:ZLowe@hkminc.com]
Sent: Tuesday, July 08, 2008 4:37 PM
To: Susan Stodola
Subject: RE: West Winds Phase 4 - Stormwater Report
Sue,
Regarding your third comment, there are gutter flow calculations in the last three pages of Appendix B. The 'Max Gutter
Capacity at design slope' column (furthest right) is the capacity with 0.15' of freeboard on the curb. The 'Q' value to the
left contain the calculated flows at the design slope.
Let me know if you need further clarification on this issue.
Zach Lowe, P.E.
HKM Engineering
A Division of DOWL, LLC
920 Technology Blvd, Suite A
Bozeman, MT 59718
406.586.8834 (phone)
406.586.1730 (fax)
2
Phase 4: Stormwater Investigation Report June 2008
1) Catch Basin, & Curb Cut Openings— excessive sediments shall be removed either
manually(with a shovel) or with a vacuum truck and flushed. E
2) Storm Mains—Mains shall be flushed if necessary.
3) Detention Pond—A stake will be set six (6) inches above the original bottom of the
basin. If sediment is over the stake, it must be removed and the basin must be
revegetated according to the original landscape plan.
The Homeowners Association is responsible for conducting the inspection program and
maintaining the storm facilities outside of the public right-of-way—this typically includes the
retention and detention ponds. During the annual stormwater inspection, if any facility within
the street right-of-way needs attention, the Homeowners Association should contact the City of
Bozeman Streets Department and inform them of the problem.
Conclusion
This report establishes the projected stormwater flows, detention requirements and conveyance
recommendations for the Phase 4 Subdivision of the West Winds Planned Community. The
basis for this report is the approved West Winds P.U.D. application of September 9, 2005.
Page 8 of 7
"G1 E E R I N�
DETENTION POND
VOLUME CALCULATIONS
1
t
Weighted C Factors
Phase Basin Commercial Single-Family Road ROW Open Space/Park Total Basin Weighted
Area ac Area ac Area ac Area ac Area ac C-Factor
3 3A 0.95 0.00 1.04 0.00 1.99 0.76
3 3B 6.37 1.09 1.62 0.38 9.46 0.62
4 4A 0.88 0.00 0.00 0.00 0.88 0.60
4 4B 0.62 0.00 0.00 0.00 0.62 0.60
4 4C 4.60 0.00 0.63 0.00 5.23 0.64
4 4D 4.71 0.00 1.22 0.21 6.14 0.65
4 4E 2.33 0.79 0.65 0.39 4.16 0.59
5 5A 4.34 0.00 0.44 0.00 4.78 0.63
5 513_1 2.44 1 0.00 0.43 0.00 2.87 0.64
Development T pe C-Value
Commercial 0.6 (Senior/Retirement/Assisted Living)
Single-Family 0.5
Road ROW 0.9
Open Space/Park Area 0.2
f
f
i
f
i
Storage Requirements for Temporary Detention Pond 1
(Contributing Basins: 3A,4A through 4D, 5A and 513)
The following calculations were used to determine the minimum required storage volume for the storm water
runoff from the basins contributing to Pond 1. The volumes were calculated using the Rational Method,and the
detention facilities were sized based on a 10-year 2-hour storm event.The calculations are for Basins 3A,4A
and 5 as routed to temporary Detention Pond 1.
Area= 22.51 Acre
C= 0.2 Open Land
Calculate Time of Concentration (T j
Existing Conditions:
S=2.60%
C=0.20 Open Land Conditions
Assume: L=710 ft.--(300 ft-sheet flow/410 ft shallow flow)
From Figure 1-1,Tc= 35.5 min.(overland flow)
Using Mannings Equation, n=0.035,S =2.60%,calculate channel flow
L= 540 ft
R= 0.92 ft
v= 6.48 ft/sec
Tc= 1.4 min
Total Tc= 36.9 min
Calculate Pre-developed Storm Intensity at Tc
From Figure 1-3, using the 10 year event, I=0.64Tc'-"
I = 0.88 in/hr
Calculate Pre-developed Peak Runoff Rate
Q10= ciA,using the above parameters.
Qio= 3.95 cfs
Calculate Developed Minimum Required Volume Storage For 10-Year Event
CR= 0.50 Residential-High Density A(ac)= 0.00
CcN= 0.60 Senior Living A(ac)= 18.54
CP= 0.20 Parkland/Openspace A(ac)= 0.21
CIMP= 0.90 Impervious/Pavement A(ac)= 3.76
C= 0.65 Weighted Average Total 22.51
1
Pond 1
0
Developed Developed Pre-developed
Storm Duration Intensity Runoff Rate Runoff Volume Release Volume Required Storage
(Minutes) (in/fir) (cfs) (cf) (cf) (cf)
5 3.2185 46.83 14,049 1,186 12,863
` 7 2.5862 37.63 15,804 1,660 14,144
9 2.1964 31.96 17,257 2,134 15,123
11 1.9278 28.05 18,513 2,609 15,904
13 1.7295 25.16 19,628 3,083 16,545
15 1.5759 22.93 20,636 3,557 17,079
J 17 1.4527 21.14 21,560 4,032 17,528
19 1.3514 19.66 22,416 4,506 17,910
21 1.2663 18.42 23,215 4,980 18,235
' 23 1.1936 17.37 23,966 5,455 18,511
.f 25 1.1306 16.45 24,676 5,929 18,747
27 1.0755 15.65 25,350 6,403 18,946
29 1.0266 14.94 25,992 6,878 19,114
31 0.9831 14.30 26,605 7,352 19,253
1 33 0.9439 13.73 27,194 7,826 19,368
35 0.9085 13.22 27,760 8,301 19,459
37 0.8763 12.75 28,305 8,775 19,530
39 0.8468 12.32 28,831 9,249 19,582
41 0.8197 11.93 29,340 9,724 19,617
43 0.7947 11.56 29,834 10,198 19,636
45 0.7716 11.23 30.312 10,672 19,640
47 0.7501 10.91 30,777 11,147 19,630
49 0.7300 10.62 31,229 11,621 19,608
51 0.7113 10.35 31,670 12,095 19,574
53 0.6937 10.09 32,099 12,570 19,529
55 0.6772 9.85 32,518 13,044 19,474
57 0.6617 9.63 32,927 13,518 19,408
59 0.6470 9.41 33,327 13,993 19,334
E 61 0.6332 9.21 33,718 14,467 19,251
63 0.6200 9.02 34,101 14,941 19,159
65 0.6076 8.84 34,476 15,416 19,060
1
Calculate Minimum Surface Area For Storm Treatment
Assume: 1. Non-flocculant particles
2. Settling velocity of 40 micron particles=0.0069 ft/sec
Design Release Rate= 3.95 cfs
Minimum Area = 573 sf
Basin Sizing(Temporary Detention Pond A)
Sized to detain the stormwater runoff from Basins 3A,4A-D,5A and 5B.
Vrequirod= 19,640 cf
i
Pond 1
POND 1
1200 140
r
1000
o ► y / 120
r W
800 / —/ 100
LLI
w 7/0
ILL I /
z_ / I V Ii
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a 400 / ( 60
., ZZ
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FIGURE I-1 TIME OF CONCENTRATION (Rational Fomiulal
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28
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Storage Requirements for Temporary Detention Pond 2
(Contributing Basins: 3B and 4E)
The following calculations were used to determine the minimum required storage volume for the storm water
runoff from the basins contributing to Pond 2. The volumes were calculated using the Rational Method,and
the detention facilities were sized based on a 10-year 2-hour storm event.The calculations are for Basins 3B
and 4B as routed to temporary Detention Pond 2.
Area= 13.62 Acre
C= 0.2 Open Land
Calculate Time of Concentration(Tc)
Existing Conditions:
S=2.40%
C=0.20 Open Land Conditions
Assume: L=915 ft.--(300 ft-sheet flow/615 ft shallow flow)
9
From Figure 1-1,Tc= 40 min.(overland flow)
Using Mannings Equation, n =0.035,S=2.4%,calculate channel flow
L= 390 ft
R= 0.92 ft
v= 6.22 ft/sec
Tr= 1.0 min
Total Tc= 410 min
Calculate Pre-developed Storm Intensity at T,
From Figure 1-3, using the 10 year event, I=0.64Tc-0'65
I = 0.82 in/hr
Calculate Pre-developed Peak Runoff Rate
Q10= ciA, using the above parameters.
Q10= 2.23 cfs
Calculate Developed Minimum Required Volume Storage For 10-Year Event
CR= 0.50 Residential- High Density A(ac)= 1.88
CCN= 0.60 Senior Living A(ac)= 8.70
CP= 0.20 Parkland/Openspace A(ac)= 0.77
CiMP- 0.90 Impervious/Pavement A(ac)= 2.27
r C= 0.61 Weighted Average Total 13.62
1
I Ir
Pond 2
1
9
-� Developed Developed Pre-developed
Storm Duration Intensity Runoff Rate Runoff Volume Release Volume Required Storage
(Minutes) (in/hr) (cfs) (cf) (CO (cf)
5 3.2185 26.90 8,069 669 7,400
7 2.5862 21.61 9,077 937 8,140
a 9 2.1964 18.36 9,912 1,205 8,707
11 1.9278 16.11 10,633 1,473 9,161
13 1.7295 14.45 11,274 1,740 9,533
15 1.5759 13.17 11,853 2,008 9,844
' 17 1.4527 12.14 12,383 2,276 10,107
i J 19 1.3514 11.29 12,875 2,544 10,331
21 1.2663 10.58 13,334 2,812 10,522
23 1.1936 9.97 13,765 3,079 10,686
25 1.1306 9.45 14,173 3,347 10,826
j 27 1.0755 8.99 14,560 3,615 10,945
29 1.0266 8.58 14,929 3,883 11,046
31 0.9831 8.22 15,281 4,150 11,131
33 0.9439 7.89 15,619 4,418 11,201
35 0.9085 7.59 15,944 4,686 11,258
37 0.8763 7.32 16,257 4,954 11,304
39 0.8468 7.08 16,560 5,221 11,338
U 41 0.8197 6.85 16,852 5,489 11,363
43 0.7947 6.64 17,135 5,757 11,378
45 0.7716 6.45 17,410 6.025 11,386
47 0.7501 6.27 17,677 6,292 11,385
i" 49 0.7300 6.10 17,937 6,560 11,377
51 0.7113 5.94 18,190 6,828 11,362
53 0.6937 5.80 18,436 7,096 11,341
55 0.6772 5.66 18,677 7,363 11,314
57 0.6617 5.53 18,912 7,631 11,281
59 0.6470 5.41 19,142 7,899 11,243
t
t
Calculate Minimum Surface Area For Storm Treatment
ll
Assume: 1. Non-flocculant particles
2. Settling velocity of 40 micron particles=0.0069 ft/sec
E. Design Release Rate= 2.23 cfs
Minimum Area= 323 sf
f Basin Sizing (Temporary Detention Pond B)
{ Sized to detain the stormwater runoff from Basins 3B and 46.
l Vrequlred 11,386 cf
I
I
I
Pond 2
�o N Z
1200 140
p � r
z / /
1000 ° o , 120
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cr
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40 0 �c ' ��
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FIGURE I-1 TIME OF CONCENTRATION Rational Formula
28
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`! Temporary Stormwater Detention Ponds
J
The following tables were used to determine the detention pond volumes. The volumes were
calculated by using the prismoidal method and are based on the detention pond configuration shown
t� in Fig 2. All elevations are assumed.
I� DETENTION POND 1
POND ELEV AREA VOLUME VOLUME,,, , Gomme-r t
Li ESIGN ft ft3 ft
'!.5 12,158 0 0 bottom
O G 98 13,179 6,333 6,333
j Z z 98.5 14,239 6,853 13,185
�
a 99 15,339 7,393 WSE (vs. 19,640 cf regd.)
_ 0 99.5 16,444 7,944 28,522
�1 100 17,658 8,524 37,046 to
Surface Area = 15,399 sf (vs. 573 sf reqd.)
( � DETENTION POND 2
FIUME.,, 'Comment
ft3 -
97.5 6,463 0 0 bottom
O LA98 7,221 3,419 3,419
wZ98.5 8,019 3,808 7,228
a 99 8,856 4,217 WSE (vs. 11,386 cf regd.)
0 99.5 9,734 4,646 16,090
J 100 10,650 5,094 21,185 to
Surface Area =8,856 sf (vs. 323 sf reqd.)
{
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L
ll
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1
Storage Requirements for Temporary Retention Pond 3
(Contributing Basins: 4C and 5A)
The following calculations were used to determine the minimum required
storage volume for stormwater runoff. The volumes were calculated using
the Rational Method, and the retention facilities were sized based on a 10-
year 2-hour storm event. The retention pond is sized to store the runoff
Total Area = 10.01 acres
Weighted C = 0.63
I = 0.41 in./hr.
Determine post-developed runoff rate:
Q = CxIxA
= 2.59 cfs
LA Determine minimum required storage volume:
f V= 7200xQ
Li = 18,677 cf
In the event the pond overflows, excess water will be released towards the Winter Park Street storm drainage
conveyance system, which has been sized to handle the additional flows.
The following table was used to determine the retention pond volume. The volumes were
calculated by using the prismoidal method and are based on the retention pond with 5:1 sideslopes
as shown in Figures 1 and 2 attached.
L_J � POND ELEV AREA VOLUME VOLUMEsum Comment
DESIGN (ft2) (ft3 ft'
l s. 4700.00 11,028 0.00 0.00 bottom
z 4700.50 12,000 5,755 5,755
10
Z 4701.00 13,012 6,251 12,007
:w p 4701.50 14,064 6,767 18,774 WSE
W ° 4702.00 15,155 7,303 26,077
( a 4702.50 16,285 7,858 33,935 top
1_
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CONVEYANCE FACILITY
CALCULATIONS
1,
! Contributing Areas&Weighted C Factors
Pine Segment C Factor Area ac
1.
L-1
Commercial 0.6 13.91
Single 0.5 0.00
LI Roads 0.9 1.93
Park 0.2 0.00
Weighted/Total 0.64 15.84
L_2
Commercial 0.6 14.91
Single 0.5 0.00
Roads 0.9 1.97
Park 0.2 0.00
i- Weighted/Total 0.64 16.88
� L_3
Commercial 0.6 2.45
t $ Single 0.5 0.00
Roads 0.9 1.04
Park 0.2 0.00
Weighted/Total 0.69 3.49
`t..1
L-4
Commercial 0.6 3.06
Single 0.5 0.00
Roads 0.9 1.15
IA Park 0.2 0.00
Weighted/Total 0.68 4.21
L-5
Commercial 0.6 18.41
Single 0.5 0.00
Roads 0.9 3.48
Park 0.2 0.00
i Weighted/Total 0.65 21.89
L-6
Commercial 0.6 6.42
Single 0.5 1.09
Roads 0.9 1.62
Park 0.2 0.38
Weighted/Total 0.62 9.51
L-7
Commercial 0.6 8.14
Single 0.5 1.38
Roads 0.9 1.72
Park 0.2 0.38
WeightedlTotal 0.62 11.62
t
L_8
Commercial 0.6 8.59
Single 0.5 1.85
Roads 0.9 2.13
Park 0.2 0.38
Weighted/Total 0.62 12.95
r L_9
Commercial 0.6 8.94
Single 0.5 0.00
Roads 0.9 1.07
Park 0.2 0.00
( Weighted/Total '0.63 10.01
Storm Drainage Main L-1
The following calculations were used to size the conveyance facilities for stormwater runoff.
The volumes were calculated using the Rational Method,and the conveyance facilities were
sized based on a 25-year 2-hour storm event.
i Contributing Basin(s) 4C,4D,5A&5B (See Figure 3)
1 Area= 15.84 Acre
C= 0.64 Weighted C
Calculate Time of Concentration(TJ
Developed Conditions:
S= 0.75 %Average Slope
C= 0.64
I Find Sheet/Shallow Concentrated Tc
Assume: L=375 ft.(minimum tc=5 min)
From Figure 1-1,
g Tc(SF)= 19.0 min.
Find Channel Flow Tc(Gutter Flow&Pipe)
Using Mannings Equation,n=0.013,S=1.15%,calculate channel flow
L= 835 ft
R= 0.1355 ft
v= 3.23 ft/sec
Tc(cF)= 4.3 min
Find Total Tc
Tc=TQSF)+Tc(cF)
Total Tc(Bae;n B)= 23.3 min
Calculate Post-developed Storm Intensity at Tc
From Figure 1-3,using the 25 year event,I=0.78TC-0.64
I= 1.43 in/hr
J Calculate Post-developed Peak Runoff Rate
Q= ciA,using the above parameters.
Q= 14.41 cfs
r Calculate Pipe Capacity Provided(Storm Main L-1)
I
Q=(1.486/n)*A*FtzJ3,,S"2
I I
Given: n= 0.013 Pipe Diameter= 27 in.
A= 3.976 sf Material= PVC
R= 0.562 ft
S= 0.004 ft/ft
Q= 19.59 cfs >14.41 cfs-ok
V= 4.93 fps
Check Inlet Control on Pipe Capacity (See Following Nomograph)
HW/D= 1.0
Q= 17cfs > 14.41 -ok
Storm Drainage Main L-2
The following calculations were used to size the conveyance facilities for stormwater runoff.
The volumes were calculated using the Rational Method,and the conveyance facilities were
sized based on a 25-year 2-hour storm event.
Contributing Basin(s) 4C,41),5A&5B (See Figure 3)
Area= 16.88 Acre
C= 0.64 Weighted C
Calculate Time of Concentration(Tc)
Developed Conditions:
S= 0.75 %Average Slope
C= 0.64
F Find Sheet/Shallow Concentrated Tc
j Assume: L=375 ft.(minimum tc=5 min)
i From Figure 1-1,T
9 c(SF)_ 19.0 min.
Find Channel Flow Tc(Gutter Flow&Pipe)
J
Using Mannings Equation,n=0.013,S=1.03%,calculate channel flow
L= 989 ft
R= 0.1355 It
v= 3.06 ft/sec
Tc(cF)= 5.4 min
Find Total Tc
Tc=Tc(SF)+Tc(cF)
Total Tc(Basin B)= 24.4 min
Calculate Post-developed Storm Intensity at Tc
From Figure 1-3,using the 25 year event,I=0.78TcA.64
I= 1.39 in/hr
Calculate Post-developed Peak Runoff Rate
Q= ciA,using the above parameters.
Q= 14.88 cfs
Calculate Pipe Capacity Provided(Storm Main L-2)
Q=(1.486/n)*A'e'*Sv2
Given: n= 0.013 Pipe Diameter= 27 in.
A= 3.976 sf Material= PVC
R= 0.562 ft
S= 0.004 ft/ft
Q= 19.59 cfs >14.88 cfs-ok
V= 4.93 fps
Check Inlet Control on Pipe Capacity (See Following Nomograph)
HW/D= 1.0
Q= 17cfs >14.88-ok
Pipe L - 1 ANu -Z
1200 — 140
r L
z
-1000 ° °
Nod
120
O'
w
i 1300 10.0 z
I z
LU ,
w
lwi
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600
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Ll
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FIGURE I-1 TIME OF CONCENTRATION (Rational Formula)
I
28
PIPE _ I AN D
TM 5-820.4/AFM 88-5r Chap 4
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156 j - 6,000 0.36 inches(3.0 feet I
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PREPARED BY
BUREAU OF PUBLIC ROADS
Figure B-5. Headwater depth for corrugated metal pipe Mlverte with inlet control.
5
Storm Drainage Main L-3
The following calculations were used to size the conveyance facilities for stormwater runoff.
The volumes were calculated using the Rational Method,and the conveyance facilities were
sized based on a 25-year 2-hour storm event.
l Contributing Basin(s) 3A,4A&4B (See Figure 3)
1{ Area= 3.49 Acre
C= 0.69 Weighted C
Calculate Time of Concentration(TJ
Developed Conditions:
S= 0.50 %Average Slope
C= 0.69
i
Find Sheet/Shallow Concentrated Tc
Assume: L=150 ft.(minimum tc=5 min)
-i From Figure 1-1,T 12.0 min.
9 asF)_
1 Find Channel Flow Tc(Gutter Flow&Pipe)
a Using Mannings Equation,n=0.013.S=1.53%,calculate channel flow
L= 655 ft
R= 0.1355 ft
J v= 3.69 ft/sec
Tc(CF)= 3.0 min
Find Total Tc
TC=TC(sF)+TC(CF)
Total Tc(Basln B)= 15.0 min
iCalculate Post-developed Storm Intensity at Tc
From Figure 1-3,using the 25 year event, I=0.78Tc-0.64
I= 1.90 in/hr
Calculate Post-developed Peak Runoff Rate
Q= ciA,using the above parameters.
Q= 4.57 cfs
Calculate Pipe Capacity Provided(Storm Main L-3)
Q=(1.486/n)"A.Rv3.S112
Given: n= 0.013 Pipe Diameter= 18 in.
A= 1.767 sf Material= PVC
R= 0.375 ft
S= 0.004 ft/ft
Q= 6.64 cfs >4.57 cfs-ok
V= 3.76 fps
Check Inlet Control on Pipe Capacity (See Following Nomograph)
HW/D= 1.5
Q= 10cfs >4.57-ok
Storm Drainage Main L-4
The following calculations were used to size the conveyance facilities for stormwater runoff.
The volumes were calculated using the Rational Method,and the conveyance facilities were
sized based on a 25-year 2-hour storm event.
Contributing Basin(s) 3A,4A,4B&4D (See Figure 3)
Area= 4.21 Acre
C= 0.68 Weighted C
Calculate Time of Concentration(TJ
Developed Conditions:
S= 0.50 %Average Slope
C= 0.68
Find Sheet/Shallow Concentrated Tc
{) Assume: L=150 ft.(minimum tc=5 min)
} From Figure 1-1,TaSF)= 12.0 min.
Find Channel Flow Tc(Gutter Flow&Pipe)
)I Using Mannings Equation,n=0.013,S=1.53%,calculate channel flow
L= 807 ft
R= 0.1355 ft
v= 3.73 ft/sec
TC(cF)= 3.6 min
Find Total Tc
Tc=Tc(SF)+Tc(cF)
Total Tc(Basin B)= 15.6 min
Calculate Post-developed Storm Intensity at Tc
From Figure 1-3,using the 25 year event, I=0.78TC-0.64
I= 1.85 in/hr
Calculate Post-developed Peak Runoff Rate
Q= ciA,using the above parameters.
Q= 5.30 cfs
Calculate Pipe Capacity Provided(Storm Main L-4)
Q=(1.486/n)"A*Fe'*Sv2
Given: n= 0.013 Pipe Diameter= 18 in.
A= 1.767 sf Material= PVC
R= 0.375 ft
S == 0.017 ft/ft
Q= 13.70 cfs >5.30 cfs-ok
V= 7.75 fps
Check Inlet Control on Pipe Capacity (See Following Nomograph)
H W/D= 1.5
Q= 10cfs >5.30-ok
I
PIPE 4AID ,C=
1.200 140
z r I
I'
1000 ° 120
r
W - .. °
f O �
cn
Ju
800 / 100
4 —j �v
!!, w
w
w t=
z l l
600 / 80
W z
c� w
U
O
W
O
j 400 60
� � O
w 200 11111A / / i �,- 40 0
ol
20
/ ` C �C ' l Z MIN•
0
f FIGURE I-1 TIME OF CONCENTRATION (Rational Formula)
28
TM 6"820.4/AF M 88-5, Chap 4 I (PE L- J �Q N D L- L/
1e0-•� -10.000
1
168 - 6,000 EXAMPLE
- 156 - 6,000 0.36 inches(3.0 feel)
- 144 I 5,000 0.66cte 6•
-4.000 (3)
132 ' nw 5. 6.
f 3,000 peel)
• 180
72,000 (21 2.1 6.3 b.
a
108 (3) 2.2 6.6 4.
1 gJJ
96 5 1000 '0 IN toot 3. 4.
, —_-
u 3.
ea 600 _ 3.
- 6.00
! 500 - 2.
i 72. 4:00 -- --
300
x —
r.T 200
54 /
W 100
46 eo60
U. 42 j C 50 1.0 1.0
F
% 40 a
W W -� (.O
41 36 30 h-W ALE ENTRANCE
4
_5 33 d TYPE W
20 f1)30 1Nedrell tl' fj 8�
(2) Mildred to conform a
to,love
_e
or 27 10 (3) Projecting -
a
a 24
- 6 .7
5 To as stele(2)or 3
21 O Pnpet
4 horitoeretlT to sap(1),then -
vol eight tocliad flat through .6 .6
3 0•e0 0 solee.or rorem eo
1 f! illeetrerd. 6
2
15
1.0 .5 Ll
.5
12
PREPARED BY
BUREAU OF PUBLIC ROADS
Figure B-5. Headwater depth for corrugated metal pip&culvert,with inlet control.
Storm Drainage Main L-5
The following calculations were used to size the conveyance facilities for stormwater runoff.
The volumes were calculated using the Rational Method,and the conveyance facilities were
sized based on a 25-year 2-hour storm event.
Contributing Basin(s) 3A,4A,413,4C,4D,5A&5B (See Figure 3)
Area= 21.89 Acre
C= 0.65 Weighted C
Calculate Time of Concentration(T.)
Developed Conditions:
S= 0.75 %Average Slope
C= 0.65
Find Sheet/Shallow Concentrated Tc
Assume: L=375 ft.(minimum tc=5 min)
From Figure 1-1,T«sF)= 18.5 min.
Find Channel Flow Tc(Gutter Flow&Pipe)
Using Mannings Equation,n=0.013,S=1.03%,calculate channel flow
L= 1360 ft
R= 0.1355 ft
v= 3.06 ft/sec
TC(cF)= 7.4 min
Find Total Tc
Tc=Tc(SF)+Tc(cF)
Total Te(Basin B)= 25.9 min
Calculate Post-developed Storm Intensity at Tc
From Figure 1-3,using the 25 year event, I=0.78TC-0.64
I= 1.34 in/hr
Calculate Post-developed Peak Runoff Rate
Q ciA,using the above parameters.
Q= 18.93 cfs
Calculate Pipe Capacity Provided(Storm Main L-5)
Q=(1.486/n)"A*R2i3,S1/2
Given: n= 0.013 Pipe Diameter= 27 in.
A= 3.976 sf Material= PVC
R= 0.562 ft
S= 0.004 ft/ft
Q= 19.59 cfs > 18.93 cfs-ok
V= 4.93 fps
Check Inlet Control on Pipe Capacity (See Following Nomograph)
HW/D= 1.1
Q= 20 cfs > 18.93-ok
} pipe
�-5
-200
i 140
1I V - r
1000 ° 120
O
n N
_ W
800 I I ioo
r r _z
W
LL
? — a
v 600 r 60 w
/ U
r y
o �
G W
J O
j 400 60 _
Z
/ I
I W
w 200 40 O
- — - —
I —
0 20
B.r
o
FIGURE I-1 TIME OF CONCENTRATION (Rational Formula
28
TM 5-820-4/AFM 88-5, Chap 4 P l PE 1--5
-too-- -10.000
168 6,000 EXAMPLE
- 156 6,000 D-36 inches(3.0 feel) �2� -
- 144 I - 5.000 0.66 cte 6•
- 4.000
(32 � ,H�s Hw 5. S.
1 f - 3,000 D itself 6.
. 120 s (1) 4.6 3.4 4." 112
a2.000 (2) 2.1too i (3) 2.2 6.64•
ve0 is foot 3. 4.
96 1.000 �3.
84 � 600 600
500 2.
72• 400 2.300 / o .
60 2001.65
_ 54 F
WW 100
a6
x-
13
60
LL
42 H 50 1.0 1.0
j 40 d
W e 1.0
36 30 _SCALE ENTRANCE tr $
TYPE Iv
a 33 @- .9
b 0 (1) Hood•ell C' 8 9 30 (2) Mitered to conform
to slope S _6
a
27 10 (3) ►rs)ectlq
dY 24 6 .7 .7
6 7
5 TO e$e$solo(1)or 3
2 f ( 1 project
4 herlsentelly to @Coll (1).two -
eCo ttoidht leetlnod list throodA .6 .6
3 0 end 0-help,or reverse eo
16 Nlrstreted. ,6
2
15
1.0 5
.5
—' 12
i
I
PREPARED BY
{ BUREAU OF PUBLIC ROADS
1
Figure B-5. Headwater depth for corrugated metal pipe culverta with inlet control.
I
I
i
)
lei
I Storm Drainage Main L-6
The following calculations were used to size the conveyance facilities for stormwater runoff.
The volumes were calculated using the Rational Method,and the conveyance facilities were
sized based on a 25-year 2-hour storm event.
Contributing Basin(s) 3B&4E (See Figure 3)
Area= 9.51 Acre
C= 0.62 Weighted C
4
Calculate Time of Concentration(TJ
i Developed Conditions:
S= 1.50 %Average Slope
t C= 0.62
e
Find Sheet/Shallow Concentrated Tc
Assume: L=310 ft.(minimum tc=5 min)
From Figure 1-1,T�(sF)= 14.5 min.
Find Channel Flow Tc(Gutter Flow&Pipe)
Using Mannings Equation,n=0.013,S=0.78%,calculate channel flow
L= 635 ft
R= 0.1355 It
v= 2.66 ft/sec
TC(cF)= 4.0 min
Find Total Tc
Tc=Tc(SF)+Tc(cF)
Total Tc(Basin B)= 18.5 min
Calculate Post-developed Storm Intensity at Tc
From Figure 1-3,using the 25 year event,I=0.78Tv-0-64
1= 1.66 in/hr
f Calculate Post-developed Peak Runoff Rate
t ,
Q= ciA,using the above parameters.
f Q= 9.83 cfs
1
1
Calculate Pipe Capacity Provided(Storm Main L-6)
( Q=(1.486/n)"A*Ry3'SU2
L
Given: n= 0.013 Pipe Diameter= i8 in.
A= 1.767 sf Material= PVC
R= 0.375 ft
S= 0.013 ft/ft
Q= 11.98 cfs >9.83 cfs-ok
V= 6.78 fps
i
I Calculate Inlet Capacity (See Following Nomograph)
HW/D= 1.5
Q= 10cfs >9.83-ok
i
� I
i
Storm Drainage Main L-7
The following calculations were used to size the conveyance facilities for stormwater runoff.
The volumes were calculated using the Rational Method,and the conveyance facilities were
j sized based on a 25-year 2-hour storm event.
Contributing Basin(s) 3B&4E (See Figure 3)
Area= 11.62 Acre
j C= 0.62 Weighted C
Calculate Time of Concentration(TJ
Developed Conditions:
S= 1.50 %Average Slope
C= 0.62
i
Find Sheet/Shallow Concentrated Tc
Assume: L=310 ft.(minimum tc=5 min)
From Figure 1-1,Tc(SF)= 14.5 min.
Find Channel Flow Tc(Gutter Flow&Pipe)
- ' Using Mannings Equation,n=0.013,S=0.80%,calculate channel flow
L= 750 It
R= 0.1355 ft
v= 2.70 ft/sec
T((CF)= 4.6 min
Find Total Tc
Tc=Tc(SF)+TacF)
Total Tc(Basin B)= 19.1 min
Calculate Post-developed Storm Intensity at Tc
From Figure 1-3,using the 25 year event,I=0.78Tv-0-64
1= 1.62 in/hr
Calculate Post-developed Peak Runoff Rate
Q= ciA,using the above parameters.
Q= 11.67 cfs
Calculate Pipe Capacity Provided(Storm Main L-4)
Q=(1.486/n)•A Fe*S"
Given: n= 0.013 Pipe Diameter= 21 in.
A= 2.405 sf Material= PVC
R= 0.437 ft
S= 0.009 ft/ft
Q= 15.03 cfs > 11.67 cfs-ok
V= 6.25 fps
Check Inlet Control on Pipe Capacity (See Following Nomograph)
HW/D= 1.3
Q= 13cfs >11.67-ok
LA
Storm Drainage Main L-8
The following calculations were used to size the conveyance facilities for stormwater runoff.
The volumes were calculated using the Rational Method,and the conveyance facilities were
sized based on a 25-year 2-hour storm event.
Contributing Basin(s) 3B&4E (See Figure 3)
Area= 12.95 Acre
C= 0.62 Weighted C
Calculate Time of Concentration(TJ
Developed Conditions:
S= 1.50 %Average Slope
C= 0.62
Find Sheet/Shallow Concentrated Tc
Assume: L=310 ft.(minimum tc=5 min)
J From Figure 1-1,TasF)= 14.5 min.
Find Channel Flow Tc(Gutter Flow&Pipe)
L_J Using Mannings Equation,n=0.013,S=0.80%,calculate channel flow
L= 960 It
R= 0.1355 ft
v- 2.70 ft/sec
TO(cF)= 5.9 min
Find Total Tc
Tc=Tc(SF)+Tc(cF)
I Total TO(easin e)= 20.4 min
Calculate Post-developed Storm Intensity at Tc
From Figure 1-3,using the 25 year event, I=0.78Tc-0.A
I= 1.55 in/hr
Calculate Post-developed Peak Runoff Rate
Q= ciA,using the above parameters.
Q= 12.55 cfs
I
Calculate Pipe Capacity Provided(Storm Main L-5)
Q=(1.486/n)*A*Rv3*Sv2
i
Given: n= 0.013 Pipe Diameter= 21 in.
A= 2.405 sf Material= PVC
R= 0.437 ft
l S= 0.009 ft/ft
Q= 15.03 cfs > 12.55 cfs-ok
V= 6.25 fps
Check Inlet Control on Pipe Capacity (See Following Nomograph)
HW/D= 1.3
Q= 13cfs >12.55-ok
1200 I 140
I
-1000 120
w —
o'
w
800 ' ! 100
w
w /
w 600 / a z
U / w
U
0 G ti
J ' /
400 y 60 r
~ I 1 ' O
Z / / r x /
w 200 / 40 0
i
0 20
i i
I c
0
f
FIGURE I-1 TIME OF CONCENTRATION (Rational Formula)
I
28
TM 5-820.4/AFM 88-5e Chap 4 Pipe
e l�
-le0 10.000
166 a.000 EXAMPLE ()
- 156 - 6.000 0•36 tnMn(3.0 feel)
144 I 5,000 0-66 cfe 6•
4,000 (3)
i 132 e ' 1tw S. 6.
3,000 (feet)
q
120 5.4
(1) 1.e 6L_. 6.
y 1- 2.000 (2) 2.1 4.3 5.
406 (a) t.t 6.6 4.
'0 In foot 3. 4.
9.6 1.000
�' Boo 3'
In3.
64
600
Soo 2.
72- - 400 __
� .
300 / 2 2.
z
1.5
60 0 200
LT �%/ 1.6 1.5
54 g / w
w 100
i 46
a
cis o so z
42 V) 50 C = 1.0 1.0
p
j 40 d
Fw' 36 c 1.0 fL
_
w 30 ALE ENTRANCE tr
q 33 b TYPE
t0 •8
U) Meldrell 30 d .e .6
(t1 mitered to conform R
to stop# ILI
27 10
a
fat /rojecHq
a 24 6 T .7
6 To goo Sella(2)or !
21' ( 1►rgecf
4 ASritenfellr 1e$Cold (1).then
use Straight intllnod line farov,pA .6 f)
3 0 end 0 voelet,or reverse eS
16 )Ilrofroted. .6
2
(S
1.0 � .S
5
12
PREPARED BY
BUREAU OF PUBLIC ROADS
h'igure B-5. Headwater depth for corrugated metal pipe culverta.with inlet control.
i
TM 5-820.4/AFM 88-5, Chap 4 PIPES C. - 7 AND - 8
ISO- 10.000
166 6.000 EXAMPLE {
156 - 6.000 0.36 inches(3.0 feel)
�
144 I 5'O Q.66 ctt G.
4.000
Nr u 5. 6.
132 3.000 O (het)
(1) 4.6 3.4 6.
(20 5r.-.
- 4. '
a 2.000 (el 2.1 4.3 S.
108 i (3) 2.2 6.6 4.
ggJ '0 in feat 3. 4.
1 } 95 5 1,000 - - -
I 3.
600 3.
84 a 600
500 2.
72, - 400 -- --
rn 2. 2.
300
6o 0 200 �E�
x 6�►% 1.5 1.5
-54 ( /
Q W 100
w 48
80/
60 z
0 42 j C 50 H 1.0 1.0
% 40. a
W
36 � ALE ENTRANCE ac
a 33 b TYPE W
t- .8
b 20 (q Needwsto � .8 .6 30 (1►. Mitered to conform Q
to loop. r L6 27 10 (3) projecting -
F
24 8 7 -.7
5 To toe Stole 2 at 3
21 O O prefect
4 horieentelly to stele(q,then
one straight Inclined line fhreogh .6 .6
3 0 sad 0 oesteo,or rotaeo es
18 illustrated. .6
2
i
1.0 .5
.5
12
1
L�
PREPARED BY
f BUREAU OF PUBLIC ROADS
Figure B-5. Headwater depth for cotwated metal pipe culverts with inlet control.
r
i 5
l
l� Storm Drainage Main L-9
The following calculations were used to size the conveyance facilities for stormwater runoff.
I� The volumes were calculated using the Rational Method,and the conveyance facilities were
I sized based on a 25-year 2-hour storm event.
Contributing Basin(s) 4C&5A (See Figure 3)
Area= 10.01 Acre
I� C= 0.63 Weighted C
Calculate Time of Concentration(TJ
Developed Conditions:
S=0.75 %Average Slope
C= 0.63
Find Sheet/Shallow Concentrated Tc
Assume: L=375 ft.(minimum t�=5 min)
From Figure 1-1,Tc(SF)= 19.2 min.
Find Channel Flow Tc(Gutter Flow&Pipe)
Using Mannings Equation,n=0.013,S=1.10%,calculate channel flow
L= 678 ft
R= 0.1355 ft
v= 3.16 ft/sec
TC(cF)= 3.6 min
Find Total Tc
Tc=Tc(SF)+Tc(cF)
Total Tc(Basin B)= 22.8 min
Calculate Post-developed Storm Intensity at Tc
From Figure 1-3,using the 25 year event, I=0.78Tc-0,64
I= 1.45 in/hr
Calculate Post-developed Peak Runoff Rate
Q= ciA,using the above parameters.
Q= 9.17 cfs
Calculate Pipe Capacity Provided(Storm Main L-6)
Q=(1.486/n)"A"R2J3*S1/2
Given: n= 0.013 Pipe Diameter= 18 in.
A= 1.767 sf Material= PVC
R= 0.375 ft
S= 0.010 ft/ft
Q= 10.50 cfs >9.17 cfs-ok
V= 5.94 fps
Calculate Inlet Capacity (See Following Nomograph)
HW/D= 1.5
Q= 10cfs >9.17-ok
1200 140
Tv—
r �
-1000 ° —
o / I 120
LU
o`
N
w
a00
/
V 1°°
w
w _
w
Z I
I�—
w 600 80 Z
w
Q G w
J O
j 400 60-i ——--—6 I
/ /
i w
w 200 4A
- - - — —
i_! I
— I
I
0
� �• / � 20
j C
I
l _
I
0
I •
I
l_J
I
FIGURE 1-1 TIME OF CONCENTRATION (Rational Fonnula
I
I
28
TM 5-820-4/AFM 88-5, Chap 4 ` 1°C
a.
-1e0--# -10.000
166 f 6,000 EXAMPLE
- 156 - 6r000 D.36 inches(3.0 feel!i
144 G.
5.000 0.66 cfI
4.000
5. 6.
3.000 Rfefl
j . 120 I.e 4.'-
`t (1) s.4
1 ` 2.000 (Pi !.1 6,; S.
toe i (3) t.2 i.6 4•
a 00 IN het 3. 4.
96 1,000 000 -
e4 3.
600
S00 - 2.
y h T2. - 400 -- --
300 / 2. 2.
Z /
� 60 0 200
6�►% L5 1.5
54 / w
f-
W W 100
--mot 46 � eO/
c 0� 60 z
4
48 V1 50 F=- 1.0 1.0
� � G
0 % 40 IL
36 1.0
m 30 ALE ENTRANCE
a 33 0 TYPE tw
20 .9
0 30 U) Ilafd"oll .6
(0. witaed to eonlerrw
to flop.
a
27 10 (3) Mojfcldg
F 24
9 .7
6 .7
5 is fle fells(t)or ;21 ( j$reps
4 horiffRglll to lefts (q,Imo --
enf etffight'Refined Hot through - .6 .6
3 0 old 0 .efts$,or nvua es
I8 UWetrohl. .6
2
- IS
1.0 .5
.5
12
PREPARED BY
BUREAU OF PUBLIC ROADS
Figure B-�. Headwater depth jOr corrugated metal pipe Oulvet*with inlet control.
�' i
f«
� ° �
// ] m n
. \
o
(S \
�)
Z
\ \ R
� ) & a
° � w w
) k > �
k/ »e
: « aLL
E} / ( § § (
| 7
f } | 2 c) n
t
/{ k k ) § § \
22
I�
zo
{ Pf
i -I
§
_■
/{ \ S @ R
0{ ƒ�
\ t Jz
/ § } a ) j o00 oco oco c\§em
; 0 ° k
2m
Cj
� �° o00 o c]222 000 ci
42}}
m / V
§ ) / Lo
§ / ) ) -
u _ |
a ;) x « k�2 ) 222 ƒ Ea) J mm0
' E1co zz§ w ! e! EE§«
ID
\ k \ 0 W,a oe�z oaXI Jam£
{ \k % > &
»
§ ) ) k ) ■
\ 0
0
i
6wr-rEjr c, P-4c,T y
5.4" (0 45')
24'
l 4• TOPS01 e
! L (TYP "R 4_R
12' ° a. a 4 a
a < d A4
V
44 4 ° v° Q" K A/1 V
o o�0 0
CRUSHED GRAVEL
0000000000000000000000000000.000
BASE — 3" MINZ
0000000000000 O O O O O O O O O 4 r A Z 5, fr
0 0 0 0 0 0 0 0 0 /
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Z
p= 9. Z6� Fr
SUB—WE COURSE
AS REQUIRED
COMPACTED SUBGRAOE
3/4• P t•SLOPE 3 �� PER I' �7z �j 7
1 2-PER 1' Sl4Pf ( 3 /a
R -- '
76 y R
J Z'03% 5,4
DROP CURB FOR DRIVEWAYS DROP CURB FOR PEDESTRIAN RAMPS SPILL CURB
NO
1. Subgrade or base course compaction shall conform to section 02230 (M.P W Specs., 1996 ed.)
2- Controclion joints shall be placed at 10' intervals and shall have a minimum depth of 3/4" and minimum width of 1/9'
3. 1/2' expansion joint moteriol shall be placed at all P.C.s, P T.s, curb returns and of not more than 300' Intervals. The
expansion material shall,extend through the full depth of the curb and gutter.
4. No curb and gutter shall be placed without o final form inspection by the City Engineer or his representative.
5. Concrete shall be Class M-4000.
6. Crushed grovel boss shall meet the requirements of Section 02235 (MPW SPECS, 2003 ed.) For curb and
gutter replacement projects, washed rock may be used for the gravel base.
CITY OF BOZEMAN SCALE: INTEGRAL CONCRETE NO. 02528-1
STANDARD DRAWING NONE CURB & GUTTER Revised
Mar. 2006
OUTLET ORIFICE
SIZING
I�
Outlet Discharqe Structure Sizinq
I
The following calculations were used to determine the discharge orifice sizing:
Q =Cd*A*(2*g*h)u2
i Solving for A,
F
A=Q/Cd*(2*g*h)"2
_!
Flow Control Manhole 1 (Detention Pond 1): xJ
Manhole Inverts (elevations assumed):
Q= 3.95 cfs Rim El = 100.00
Cd= 0.62 Inv. El.= 97.50 (bottom of pond)
g= 32.2
h = 1.50 ft
A= 93.41 in
D= 10.9 in
Flow Control Manhole 2 (Detention Pond 2):
f
Manhole Inverts (elevations assumed):
Q = 2.23 cfs Rim El = 100.00
Cd= 0.62 Inv. El.= 97.50 (bottom of pond)
g= 32.2
h = 1.50 ft
A= 52.73 in2
D= 8.2 in
f
I
L.
I.
f�
� • •
t
1
1
1
1
1
1
1
1
1
1