HomeMy WebLinkAbout12 - Design Report - South University District Ph 1 - Storm Storm Water Plan
South University District — Phase 1
February 2012
Submitted to:
City of Bozeman Engineering Department
20 East Olive
Bozeman, MT 59715
Prepared by:
Stahly Engineering and Associates
7585 Shedhorn Drive
Bozeman, MT 59718
(406) 522-9526
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South University District — Phase 1
Storm Water Plan
Contents
Existing Conditions and General Design Criteria
Storm Drainage Plan Description
Estimation of Runoff
Pre-development Runoff— Phase 1
Post-development Runoff— Phase 1
Pre-development Runoff— Phase 2-3
Post-development Runoff— Phase 2-3
Storage/Treatment Facilities
Discharge Structure and Storm Sewer
Curb Capacity
Inlet Capacity
Facilities Maintenance
Figures and Tables
Figure 1. Detention Pond Basin Exhibit
(separate figure in Appendix)
Figure 2 Inlet Basin Exhibit
(separate figure in Appendix)
Table 1. Runoff Calculations — Phase 1
Table 2. Runoff Calculations— Phases 2-3
Appendix
Detention Basin Calculations
Inlet Basin/Pipe Sizing Calculations
Gutter Capacity Calculations
Outfall Structure Calculations
Figures/Maps
Storm Water Plan 1 2/17/2012
Existinq Conditions and General Design Criteria
The existing condition at the site for the proposed South University District (SUD)
— Phase 1 includes 17.6 acres of undeveloped agricultural land west of Bobcat
Stadium and south of the Stadium Center Subdivision within the City of
Bozeman. Down-gradient development has restricted storm drainage paths
leaving the property to the north. An existing creek (Mandeville Creek) runs
along the west edge of the property and is the only acceptable location for storm
water to leave the site. This drainage flows north through neighboring
developments.
In accordance with the City of Bozeman Design Standards and Specifications
Policy(COB Standards) an engineering analysis has been conducted for the
SLID property to limit post-development runoff to pre-development rates. Storm
runoff originating on the site will be detained on-site and released at rates less
than the pre-development rates. Furthermore, detention basins will reduce storm
water velocity and allow solids, silt, oils, grease, and other pollutants to settle
from the runoff before the flows leave the site.
Inlets and storm sewers are sized to pass the 25-year event without overtopping
roadways. Should a larger event overtop the roadways grading will divert
overflows to the west to the existing Mandeville Creek.
Storm Drainage Plan
The overall storm drainage plan for SLID — Phase 1 is depicted on Figure 2 in the
Appendix of this report. Overall drainage direction on the proposed development
is indicated by arrows showing the proposed drainage patterns and inlet
locations.
Estimation of Runoff
The rational method was used to estimate peak flow rates and volumes from
storm runoff. Standard assumptions in using the rational method include that
rainfall is uniformly distributed over a watershed for the duration of a storm event,
the peak runoff rate occurs when the storm duration equals the time of
concentration, and the runoff coefficient for a watershed is constant for similar
land use. Time of concentration was determined from the slope of the basin,
rational runoff coefficient and flow length (COB Standards— Equation II.E.6).
Storm Water Plan 2 2/17/2012
Pre-development Runoff- Phase 1
A runoff coefficient of 0.20 for open land was selected for pre-development
conditions. An average overland slope of 2.5% over a basin length of 1,650 feet
provides a time of concentration of 50.4 minutes. The Bozeman OF curves
show a rainfall intensity for the 10-year design storm event of 0.72 in/hr.
Applying this over the 17.6 acre site produces a runoff flow rate of 2.52 cfs at the
downstream end of the basin.
Post-development Runoff- Phase 1
Post-construction runoff was calculated using a runoff coefficient of 0.60
(commercial neighborhood) to account for future site development in accordance
with the master plan. The increased impervious area reduces the time of
concentration to 28.0 minutes. The Bozeman IDP curves show a 10-year storm
intensity of 1.05 in/hr. The rational method provides a 1 0-year peak runoff rate of
11.08 cfs. The same analysis for a 25-year event provides a peak runoff rate of
14.54 cfs.
Table 1 Runoff Calculations - Phase 1
Pre-development Post-Development Post-Development
Open Land Commercial Commercial
Land Use Neighborhood Neighborhood
Drainage Area (acres) 17.6 17.6 17.6
Slope (%) 2.5 2.5 2.5
Overland Runoff Coefficients 0.2 0.6 0.6
Frequency Adjustment Factor, Cf 1 1 1.1
Design Storm Frequency 1 0-year 16-year 25-year
Basin Length (ft) 1,650 1,650 1,650
Time of Concentration, Tc(min) 50.4 28.0 28.0
Intensity at Tc (Figure 1-2 pg.
29)(in/hr) 1 0.72 1.05 1.38
Runoff Rate(cfs) 1 2.52 11.08 14.54
The storm water detention pond for Phases 2 and 3 will also be constructed with
SUD - Phase 1 and was therefore analyzed to size the basin needed for this
future development.
Pre-development Runoff- Phase 2-3
A runoff coefficient of 0.20 for open land was selected for pre-development
conditions. An average overland slope of 2.5% over a basin length of 2,620 feet
provides a time of concentration of 63.5 minutes. The Bozeman OF curves
show a rainfall intensity for the 1 0-year design storm event of 0.62 in/hr.
Applying this over the 36.5 acre Phase 2-3 site produces a runoff flow rate of
4.51 cfs at the downstream end of the basin.
Storm Water Plan 3 2/17/2012
Post-development Runoff— Phase 2-3
Post-construction runoff was calculated using a runoff coefficient of 0.60
(commercial neighborhood) to account for future site development in Phases 2-3
in accordance with the master plan. The increased impervious area reduces the
time of concentration to 35.3 minutes. The Bozeman IDP curves show a 10-year
storm intensity of 0.90 in/hr. The rational method provides a 1 0-year peak runoff
rate of 19.81 cfs. The same analysis for a 25-year event provides a peak runoff
rate of 26.06 cfs.
Table 2 Runoff Calculations— Phase 2-3
Pre-development Post-Development Post-Development
Open Land Commercial Commercial
Land Use Neighborhood Neighborhood
Drainage Area (acres) 36.5 36.5 36.5
Slope (%) 2.5 2.5 2.5
Overland Runoff Coefficients 0.2 0.6 0.6
Coefficients
Frequency Adjustment UFactor, Cf 1 1 1.1
Design Storm Frequenc 1 0-year 0-year 25-year
Basin Length (ft) 2,620 2,620 2,620
Time of Concentration, Tc(min) 63.5 35.3 35.3
Intensity at Tc (Figure 1-2 pg.
29)(in/hr) 1 0.62 0.90 1.19
Runoff Rate (cfs) 4.51 19.81 26.06
Storage/Treatment Facilities
Simple pond routing using the modified rational method is provided in the
Appendix at the end of the report. This spreadsheet shows a required storage of
15,245 cubic feet of runoff for the 1 0-year event for Phase 1 and 34,359 cubic
feet for Phases 2-3. The required storage is provided by 2 basins, one for the
Phase 1 runoff and one for the Phase2-3 runoff. The Phase 1 pond has a bottom
area of 8,748 square feet and 4:1 side slopes. The bottom elevation is 4928.00
and surface overflow to the west is provided at an elevation of 4930.50. The
maximum depth is 1.5 feet, with a total volume of approximately 16,344 cubic
feet. The pond for the future Phases 2-3 development has a bottom area of
21,790 square feet and 4:1 side slopes. The bottom elevation is 4930.5 and the
surface overflow to the west is provided at an elevation of 4933.00. The
maximum depth is 1.5 feet, with a total volume of approximately 35,600 cubic
feet at this depth. The detention basins are located at the northwest (down-
gradient) end of the site and will be vegetated with grass.
Storm Water Plan 4 2/17/2012
Discharge Structure and Storm Sewer
The detention basin outflow for both the Phase 1 and the Phase 2-3 development
is restricted by a typical control structure as depicted in COB Standards Figure A-
2. Using the weir calculation equation given in Section II.D.2 of the COB
Standards, the slot width of both weir structures was determined. The slot width
for the Phase 1 pond discharge structure is 5 inches and the slot width for the
Phase 2-3 discharge structure is 9 inches. These slot widths limit the discharge
from the structure to pre-developed rates at the maximum depth of 1.5 feet.
Outfall structure calculation can be found in the Appendix.
In the occurrence of an event greater than the 10-year event the ponds are sized
for, the overflow of the ponds directs flow to the west to Mandeville Creek.
Curb Capacity
Where runoff flows in SUD — Phase 1 will be partially carried in the curb and
gutter of a 35' wide road. Capacity of this curb and gutter was analyzed to
determine if the curb would be overtopped in a 25-year event and one lane of
traffic would remain open. The maximum 25-year event for any of the curb inlet
basins produces approximately 0.65 cfs of runoff. The capacity of the curb at the
minimum slope of 0.73% is 6.08 cfs at a depth of .15 feet below the top of the
curb. Therefore, curb capacities in the development are adequate for runoff
control.
Inlet Capacity
The curb inlets on the roadways in the development were analyzed to ensure
they have capacity to accept flows conveyed to them without reaching a point
0.15 feet from the top of the curb. The COB approved Neenah Foundry R-3067-
L inlet structure has a capacity of 5.98 cfs at 0.35 feet of head (0.15 below top of
curb). This capacity will convey the necessary flows.
Facilities Maintenance
The proposed storm drainage facilities will be operated and maintained by the
property owner. The owner is responsible for quarterly maintenance of all storm
water facilities. The maintenance includes, but is not limited to, visual inspection
and removal of sediment from curbs, inlets, detention basins, and outlet
structures as well as any necessary repairs to the facilities.
Storm Water Plan 5 2/17/2012
APPENDIX
DETENTION BASIN
CALCULATION
Phase 1 Runoff Calculations
Time of Concentration Calculations Preconstruction Postconstruction Storm Sewer Flow
Land Use Open Land REMU REMU
Drainage Area(acres) 17.57 17.57 17.57
Slope(%) 2.6 2.5 2.5
Runoff Coefficients 0.2 0.6 0.6
Frequency Adjustment Factor,Cf 1 1 1.1
Basin Length(ft) 1650 1650 1650
Time of Concentration(min) 50.4 28.0 24.6
Peak Flow Calculations
Design Storm 10-Year 10-Year 25-Year
Intensity at Tc (Figure 1-2 pg.29)(inlhr) 0.72 1.05 1.36
Peak Runoff Rate at Tc(Q=CIA)(cfs) 2.52 11.O6 14.54
(max release rate)
Required Storage Volume MAX VOL.
15245.30
Storm Duration Intensity Future Runoff Rate Runoff Volume Release Volume Required Storage Notes
(minutes) (inlhr) (Q=CIA)(cis) (co (cf) (cq
2 5.84 61.55 7386.06 302.37 7083.69
4 3.72 39.22 9413.99 604.75 8809.24
6 2.86 30.14 10849.39 907.12 9942.27
8 2.37 25.00 11998.70 1209.50 10769.20
10 2.05 21.62 12973.36 1511.87 11461.49
12 1.82 19.21 13828.21 1814.24 12013.97
14 1.65 17.37 14594.77 2116.62 12478.15
16 1.51 15.93 15293.07 2418.99 12874.07
18 1.40 14.76 15936.68 2721.37 13215.32
20 1.31 13.78 16535.34 3023.74 13511.60
24 1.16 12.24 17624.89 3628.49 13996.40
26 1.10 11.62 18125.63 3930.86 14194.77
28 1.05 11.07 18601.92 4233.24 14368.69
30 1.00 10.59 19056.58 4535.61 14520.97
32 0.96 10.15 19491.94 4837.99 14653.95
34 0.93 9.76 19909.95 5140.36 14769.59
36 0.89 9.40 20312.27 5442.73 14869.53
38 0.86 9.08 20700.31 5745.11 14955.20
40 0.83 8.78 21075.29 6047.48 15027.81
42 0.61 8.51 21436.27 6349.86 15088.42
44 0.78 8.25 21790.19 6652.23 15137.96
46 0.76 8.02 22131.85 6954.61 15177.25
48 0.74 7.80 22463.99 7256.98 15207.01
50 0.72 7.60 22787.26 7559.35 15227.90
52 0.70 7.40 23102.22 7861.73 15240.49
54 0.69 7.23 23409.40 8164.10 15245.30 Required Storage
56 0.67 7.06 23709.28 8466.48 15242.80
58 0.65 6.90 24002.27 8768.85 15233.42
60 0.64 6.75 24288.77 9071.22 15217.54
62 0.63 6.60 24569.12 9373.60 15195.52
64 0.61 6.47 24843.66 9675.97 15167.68
66 0.60 6.34 25112.67 9978.35 15134.33
68 0.59 6.22 25376.44 10280.72 15095.72
70 0.58 6.10 25635.21 10583.10 15052.11
72 0.57 5.99 25889.22 10885.47 15003.75
74 0.56 5.89 26138.68 11187.84 14950.114
76 0.55 5.79 26383.80 11490.22 14893.56
78 0.54 5.69 26624.76 11792.59 14832.17
80 0.53 5.60 26661.73 12094,97 14766.77
82 0.52 5.51 27094.89 12397.34 14697.55
84 0.51 5.42 27324.38 12699.71 14624.66
86 0.51 5.34 27550.34 13002.09 14548.25
BB 0.50 5.26 27772.92 13304.46 14468.45
90 0.49 5.18 27992.23 13606.84 14385.39
92 0.48 5.11 28208.39 13909.21 14299.18
94 0.46 5.04 28421.52 14211.59 14209.93
96 0.47 4.97 28631.72 14513.96 14117.76
98 0.47 4.90 28839.10 14816.33 14022.76
100 0.46 4.84 29043.74 15118.71 13925.03
102 0.45 4.78 29245.74 15421.08 13824.66
104 0.45 4.72 29445.18 15723.46 13721.72
106 0.44 4.66 29642.14 16025.83 13616.31
108 0.44 4.60 29836.71 16328.20 13508.50
110 0.43 4.55 30028.94 16630.58 13398.36
112 0.43 4.50 30218.91 16932.95 13285.96
114 0.42 4.45 30406.70 17235.33 13171.37
116 0.42 4.40 30592.35 17537.70 13054.65
118 0.41 4.35 30775.93 17840.08 12935.86
120 0.41 4.30 30957.51 18142.45 12815.06
Phase 2 and 3 Runoff Calculations
Time of Concentration Calculations Preconstruction Postconstruction Storm Sewer Flow
Land Use Open Land REMU REMU REMU
Drainage Area(acres) 36.52 36.52 36.52 36.52
Slope(%) 2.5 2.5 2.5 2.5
Runoff Coefficients 0.2 0.6 0.6 0.6
Frequency Adjustment Factor,Cf 1 1 1.1 1.1
Basin Length(ft) 2620 2620 2620 2620
Time of Concentration(min) 63.5 35.3 31.0 25.0
Peak Flow Calculations
Design Storm 10-Year 10-Year 25-Year 25-Year
Intensity at To (Figure 1-2 pg.29)(in/hr) 0.62 0.90 1.19 1.37
Peak Runoff Rate at Tc(Q=CIA)(cis) 4.51 19.81 26.06 29.93
(max release rate)
Required Storage Volume MAX VOL.
34358.76
Storm Duration Intensity Future Runoff Rate Runoff Volume Release Volume Required Storage Notes
(minutes) (in/hr) (Q=CIA)(cfs) (cf) (cf) (co
2 5.84 127.94 15352.25 540.80 14811.45
4 3.72 81.53 19567.37 1081.60 18485.77
6 2.86 62.64 22550.93 1622.41 20928.53
8 2.37 51.96 24939.80 2163.21 22776.60
10 2.05 44.94 26965.69 2704.01 24261.68
12 1.82 39.92 28742.53 3244.81 25497.72
14 1.65 36.11 30335.86 3765.61 26550.25
16 1.51 33.11 31787.29 4326.41 27460.88
18 1.40 30.67 33125.08 4867.22 28257.86
20 1.31 28.64 34369.41 5408.02 28961.39
24 1.16 25.44 36634.10 6489.62 30144.48
26 1.10 24.15 37674.91 7030.42 30644.49
28 1.05 23.01 38664.90 7571.22 31093.67
30 1.00 22.01 39609.92 8112.03 31497.90
32 0.96 21.10 40514.83 8652.83 31862.01
34 0.93 20.29 41383.69 9193.63 32190.06
36 0.89 19.55 42219.92 9734.43 32485.49
38 0.86 18.87 43026.48 10275.23 32751.25
40 0.83 18.25 43805.89 10816.03 32989.86
42 0.81 17.68 44560,37 11356.84 33203.54
44 0.76 17.16 45291.84 11897.64 33394.21
46 0.76 16.67 46002.01 12438.44 33563.57
48 0.74 16.21 46692.38 12979.24 33713.14
50 0.72 15.79 47364.29 13520.04 33844.25
52 0.70 15.39 48018.96 14060.84 33958.11
54 0.69 15.02 46657.45 14601.65 34055.81
56 0.67 14.67 49280.76 15142.45 34138.31
58 0.65 14.34 49889.75 15683.25 34206.50
60 0.64 14.02 50465.25 16224.05 34261.20
62 0.63 13.73 51067.98 16764.85 34303.12
64 0.61 13.45 51638.61 17305.65 34332.96
66 0.60 13.18 52197.77 17846.46 34351.31
68 0.59 12.93 52746.02 18387.26 34358.76 Required Storage
70 0.58 12.69 53283.88 18928.06 34355.82
72 0.57 12.46 53811.85 19468.86 34342.99
74 0.56 12.24 54330.37 20009.66 34320.71
76 0.55 12.03 54839.86 20550.46 34289.39
78 0.54 11.82 55340.70 21091.27 34249.44
80 0.53 11.63 55833.27 21632.07 34201.20
82 0.52 11.45 66317.89 22172.87 34145.02
84 0.51 11.27 56794.90 22713.67 34081.22
86 0.51 11.10 57264.57 23254.47 34010.10
88 0.50 10.93 57727.20 23795.27 33931.93
90 0.49 10.77 58183.04 24336.08 33846.97
92 0.48 10.62 56632.35 24876.88 33755.47
94 0.48 10.47 59075.35 25417.68 33657.67
96 0.47 10.33 59512.27 25958.48 33553.79
98 0.47 10.19 59943.30 26499.28 33444.02
100 0.46 10.06 60368.66 27040.08 33328.58
102 0.45 9.93 60788.53 27580.89 33207.64
104 0.45 9.81 61203.07 28121.69 33081.38
106 0.44 9.69 61612.47 28662.49 32949.98
108 0.44 9.57 62016.87 29203.29 32813.56
110 0.43 9.46 62416.44 29744.09 32672.35
112 0.43 9.35 62811.31 30284.89 32526.42
114 0.42 9.24 63201.63 30825.70 32375.93
116 0.42 9.14 63587.51 31366.50 32221.02
118 0.41 9.04 63969.10 31907.30 32061.80
120 0.41 8.94 64346.51 32448.10 31896.41
INLET BASIN
PIPE SIZING
CALCULATIONS
Phase 'I Inlet Basin and Pipe Capacity Calculations
Inlet Basin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
Land Use REMU REMU REMU REMU REMU REMU REMU REMU REMU REMU REMU REMU REMU REMU REMU REMU REMU REMU REMU REMU REMU REMU REMU REMU REMU REMU REMU
Drainage Area acres 0.50 0.95 1.37 0.47 0.46 0.60 0.23 0.73 0.38 0.16 0.27 1.96 0.28 0.79 0.35 1.03 0.33 0.30 0.24 1.16 1.72 0.21 0.27 1.61 0.62 0.38 0.50
Slope %) 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5
Runoff Coefficients 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6
Frequency Adjustment Factor,Cf 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1
Basin Length ft 388 612 317 594 594 221 250 700 4.13 113 306 350 216 281 207 726 412 245 246 250 316 258 251 313 314 230 418
Time of Concentration min 11.9 15.0 16.0 17.0 18.0 19.0 20.0 21.0 22.0 23.0 24.0 25.0 26.0 27.0 28.0 29.0 30.0 31.0 32.0 33.0 34.0 35.0 36.0g25
E25yr
39.0 40.0
Peak Flow Calculations
Design Storm 25 r 25 r 25 r 25 r 25 r 25 r 25 r 25 r 25 r 25yr 25 r 25 r 25 r 25 r 25 r 25 r 25 r 25 r 25 r 25 r 25 r 25 r 25 r 25 r 25 r
Intensit at Tc Fi ure 1-2 .29 (in/hr 2.19 1.89 1.82 1.75 1.69 1.63 1.58 1.53 1.48 1.44 1.40 1.37 1.33 1.30 1.27 1.24 1.22 1.19 1.17 1.14 1.12 1.10 1.06 1.03 1.01
Peak Runoff Rate at Tc(Q=CIA)(cfs) 0.66 1.08 1.49 0.49 0.47 0.59 0.22 0.67 0.34 0.14 0.23 1.61 0.22 0.62 0.27 0.77 0.24 0.21 0.17 0.80 1.16 0.14 0.18 0.23 1 0.30
Phase 1 Pipe Capacity
Detention Basin A Pipe Network
Pipe Number 1A 2A 3A 4A 5A 6A 7A 8A 9A 10A 11A 12A 13A 14A 15A 16A 17A 18A 19A 20A 21A 22A 23A 24A 25A 26A 27A
Pipe Size(in) 24.00 15.00 15.00 24.00 15.00 12.00 24.00 12.00 24.00 15.00 12.00 18.00 12.00 15.00 18.00 15.00 15.00 18.00 15.00 12.00 18.00 15.00 15.00 15.00 18.00 18.00 18.00
Manning's"n" PVC 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013
Area(ft) 3.14 1.23 1.23 3.14 1.23 0.79 3.14 0.79 3.14 1.23 0.79 1.77 0.79 1.23 1.77 1.23 1.23 1.77 1.23 0.79 1.77 1.23 1.23 1.23 1.77 1.77 1.77
Wetted Perimeter ft 6.28 3.93 3.93 6.28 3.93 3.14 6.28 3.14 6.28 3.93 3.14 4.71 3.14 3.93 4.71 3.93 3.93 4.71 3.93 3.14 4.71 3.93 3.93 3.93 4.71 4.71 4.71
Hydraulic Radius ft 0.50 0.31 1 0.31 0.50 0.31 0.25 0.50 1 0.25 0.50 0.31 0.25 0.38 0.25 0.31 0.38 0.31 0.31 0.38 0.31 0.25 0.38 0.31 0.31 0.31 0.38 0.38 1 0.38
Slope ft/ft 0.0045 0.0035 10.0035 0.0025 0.0035 0.0050 0.0025 0.0050 0.0025 0.0035 0.0050 0.0100 0.0050 0.0035 0.0125 10.0035 0.00351 0.0186 0.0035 0.0050 0.0186 0.0035 0.0035 0.0035 0.0784 0.0050 0.0050
Full Flow Capacity cfs 15.22 3.83 1 3.83 11.34 3.83 2.53 11.34 2.53 11.34 3.83 2.53 10.53 2.53 3.83 11.78 3.83 3.83 1 14.36 3.83 2.53 14.36 3.83 3.83 3.83 29.49 7.45 7.45
Velocity(ft/sec) 4.84 3.12 3.12 3.61 3.12 3.22 3.61 3.22 3.61 3.12 3.22 5.96 3.22 3.12 6.66 3.12 3.12 8.13 3.12 3.22 8.13 3.12 3.12 3.12 16.69 4.21 4.21
Contributing Inlet Basin 1 2 3 NONE 4 5 6 7 NONE 8 9 10 11 12 13 14 15 NONE 16 17 18 19 20 21 22 23 24
Contributing Pipes 2A 3A NONE 5A 6A NONE 8A NONE 10A 11A NONE 13A NONE NONE 16A 17A NONE 19A 20A NONE 22A 23A NONE NONE 26A 27A NONE
4A 7A 9A 12A 14A 18A 21A 24A
15A
Actual Pipe Flow(cfs) 12.42 2.57 1.49 9.19 0.96 0.47 8.23 0.22 7.43 1.01 0.34 6.42 0.23 1.61 4.45 0.88 0.27 3.34 1.01 0.24 2.34 0.96 1 0.80 1.16 1.34 1 1.20 1.03
Detention Basin B Pipe Network
Pipe Number 1B 2B 3B 4B 5B 6B 7B 8B 9B
Pipe Size in 30.00 30.00 12.00 24.00 24.00 12.00 24.00 24.00 12.00
Mannin 's"n" PVC 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013
Area 4.91 4.91 0.79 3.14 3.14 0.79 3.14 3.14 0.79
Wetted Perimeter(ft) 7.85 7.85 3.14 6.28 6.28 3.14 6.28 6.28 3.14
Hydraulic Radius ft 0.63 0.63 1 0.25 0.50 0.50 0.25 0.50 0.50 0.25
Slope(ft/ft) 0.0179 0.0179 0.0050 0.0100 0.0050 0.0050 0.0050 0.0106 0.0050
Full Flow Capacity cfs 55.02 55.02 2.53 22.68 16.04 2.53 16.04 23.35 2.53
Velocity(ft/sec) 11.21 11.21 3.22 7.22 5.11 3.22 5.11 7.43 3.22
Contributing Inlet Basin NONE NONE 25 NONE NONE 26 NONE NONE 27.00
Contributing Pipes 2B 3B NONE 5B 6B NONE 8B 9B NONE
4B 7B
Flow Contribution from Phase 2-3(cfs) 9.98 9.98 9.98
Actual Pipe Flow(cfs) 30.86 30.86 0.39 20.49 10.51 0.23 10.28 1 0.30 0.30
GUTTER CAPACITY
CALCULATIONS
Gutter Capacity Calcs
Right-side slope X:1 0.05
Left-side slope X:1 50.00
Channel bottom width(ft) 0
Flow Depth (ft) 0.400
Flow Area (ft^2) 4.004
Wetted Perimeter(ft) 20.404
Width 0.040
Hydraulic Radius (ft) 0.196
Manning's Roughness 0.013
Slope(ft/ft) 0.010
Average Velocity(ft/sec) 3.87
Flow(ft^3/sec) 15.49
OUTFALL STRUCTURE
CALCULATIONS
Outfall Structure Sizing
South University District
Phase 1�
Pre-developed Runoff cfs � 2.52
Weir Coefficient"C 3.33
Head ft 1.5
Slot Width (in) 5
Phase 2-3
Pre-developed Runoff(Q) 4.51
Weir Coefficient"C" 3.33
Head ft 1.5
Slot Width 9
FIGURES/MAPS
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n DATE 2/6/12
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