20070566 Ver 2_Stormwater Info_20071024

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WITHERS RAVENEt_

STORMWATER CALCULATIONS
FOR
NORWOOD BLUFFS SUBDIVISION
Wake County, North Carolina
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Prepared:
October 9, 2007

Table of Contents
Section Page
Stormwater Summary 1
Wake County Stormwater Worksheets 2-11
Detention Pond Calculations 12-ZO
Minor Flood Study:
FES-2 -Outlet-1 21-25
Minor Flood Study:
HW-4 - HW-3 26-30
Roadside Ditch Calculations 31-39
Exhibits:
Stormwater Drainage Area Delineation Map EX-1
Sediment Basin Drainage Area Delineation Map EX-2
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Stormwater Narrative
The proposed Norwood Bluffs subdivision is located along Norwood Road, in Wake
County, North Carolina. The subdivision proposes to create 14 single family lots on a
30.6 acre tract.
The development is subject to the following Stormwater requirements:
Volume Control:
Volume control as determined per the Wake Stormwater ordinance must be provided, and
released over a period of 2-5 days. The required volume as determined by the Wake
County worksheets is 12,423 cf. The required volume is provided, and is released over a
period of 2-5 days.
Peak Flow Detention:
Since the project's impervious coverage exceeds 15%, the one-year post-developed peak
flow must be detained and released at a rate equal to or less than the pre-developed rate.
This requirement is met by providing additional volume as estimated by the Wake County
worksheets. The peak flow is then calculated based on the provided volume. The pre-
developmentpeak flow and the post-development peak flow are both 3.49 cfs.
Nitrogen Control:
The post-developed nitrogen export from the site is 3.75 lbs/ac/yr. Therefore, a buydown
of $3,898.69 is required.

Wake County Stormwater Worksheets
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~~~ Stormwater Management Plan s/D No.: o
Norwood Tract Date: 9/21/2007
CtJllNTY
~~,~~„ ~-A~,7~,~~ Withers & Ravenel Designer: SAH
SUMMARY INFORMATION
Site Data
Total Area: 30.56 acres
Zoning: R-8oW
Number of Lots: 14
Percent Im envious: 16.24
Volume Management Calculations
Target Curve Number: 63
Proposed Curve Number: 66
Total Volume Required:

Total Volume Provided: 30060 ft3~ ~~'~ '~E~"''
s , W l~kt: c~~ry A
28859 ft c~--,~_.~-~, ~ ~.,
Nitrogen Calculations
TN Loading from Site: 3.75 Ibs/ac/yr
Buy-down (if in NRB): $1,512.72 Before9/1/07
3898.692 After 9/1/07
Peak Flow Management Calculations:
Pre-Development Peak Flow: 3.49 cfs
Post-Development Peak Flow: 3.49 cfs
V U u / r-tE LAG ~~'-
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Wake County Stormwater Tool
Version 2.0
0
10!9/2007 10:41 AM

Stormwater Management Plan S/D No.:
yv~~ Norwood Tract Date: 9/21/2007
COUNTY Withers & Ravenel Designer: SAH
tiit3tTi-~ i~,:nsxoe.~kn
TARGET CURVE NUMBER CALCULATION
Wake County Target Curve Numbers
Zoning District A B C D
R-80W and R-80 37 60 73 79
R-40W and R-40 41 62 75 80
R-30, R-20, R-15, R-5 43 63 76 81
Site Data:
Total Site Area: 30.56 acres ""Excludes Area of Exisitng Lakes or Ponds on site
Zoning District: R-8OW
Soil Composition:
Hydrologic Soil Group Site Area
A
B 25.01
C 3.50
D 2.05
Target Curve Number:
Runoff (inches) = Q* _
Target CN
37
82% 60
11% 73
7% 79
100%
63
0.43 inches
Wake County Stormwater Tool ~~
Version 2.0 10/9/2007 10:41 AM

~rlil~~ Stormwater Management Plan s/D No.:
W~~~ Norwood Tract Date: 9/21/2007
COUNTY Withers & Ravenel Designer: SAH
POST-DEVELOPMENT CALCULATIONS I
CURVE NUMBER:
Is Data from Preliminary Plan Still Valid?
Total Area of Lots:
Number of Lots:
Impervious Area per Lot:
Impervious on Lots:
Woods on Lots:
Impervious in RMI:
Percent Impervious for Site:
Percent of Total Disconnected Impervious:
Yes
20.62 acres
14
13200 sf
20.57
33.6372
40
16.24
50 % (50% is Default. See Table 3.3)
HSG Land-use CN Area (acres)
B Lots (w/Buffer) 67 19.34 63.29%
C Lots (w/Buffer) 78 1.28 4.19%
B R/W w/Ditch Sections 87 1.8 5.89%
B Woods (C.O.S. or non-Iof Buffer) 55 4.01 13.12%
C Woods .(C.O.S. or non-lof Buffer) 70 1.94 6.35%
D Woods (C.O.S. or non-lot Buffer) 77 1.95 6.38%
B Open Space (Grassed C.O.S) 61 0.24 0.79%

Totals: 30.56 100.00%
Post-Development CN = 66
Runoff (inches) = Q* = 0.54 inches
Warnings/Notes:
CN is greater than the Target CN therefore volume management will be required.
iPercent woods on lots exceeds allowable. Please show the wooded area to be preserved on the construction drawing.
Wake County Stormwater Tool ~-
Version 2.0 ` ,J,J 10/9/2007 10:41 AM

~-~ Stormwater Management Plan S/D No.:
Norwood Tract Date: 9/21/2007
COUNTY Withers & Ravenel Designer: SAH
PRE-DEVELOPMENT CALCULATIONS
(CURVE NUMBER:
User Defined
User Defined
User Defined
User Defined
HSG Land-use CN Area (acres)
B Woods, Good Cond. 55 24.5 80.17%
C Woods, Good Cond. 70 3.5 11.45%
D Woods, Good Cond. 77 2.05 6.71
B Pasture or Open Space, Good Cond. 61 0.51 1.67%
98
98
98
98
98
98
98
98

Totals: 30.56 100.00%
Pre-development CN = 58
Runoff (inches) = Q* = 0.27 inches
ME OF CONCENTRATION:
Sheet Flow:
Sheet Flow:
Shallow Flow:
Shallow Flow:
Channel Flow:
Channel Flow:
Length (ft) Slope (ft/ft) Surface Cover Tt (hrs)
95 0.032 Woods 0.27

.522 0.405 Unpaved 0.03

Length (ft)
Slope (ft/ft)
n-value Flow
Area (ftz)
Wetted Perimeter (ft)
Tt (hrs)
636 0.028 0.065 2.0 4.0 0.07

Pre-development T~ = 0.37 hrs (Minimum 5minutes)
Wake County Stormwater Tool ~ ~j
/~~
Version 2.0 ~-- 10/9/2007 10:41 AM

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~'~ Stormwater Management Plan SID No.:
Norwood Tract Date: 9/21/2007
COUNTY Withers & Ravenel Designer: SAH
POST-DEVELOPMENT CALCULATIONS
ITIME OF CONCENTRATION:
Sheet Flow:
Sheet Flow:
Shallow Flow:
Shallow Flow:
I Channel Flow:
Channel Flow:
Length (ft) Slope (ftlft) Surface Cover T~ (hrs)
95 0.032 Woods 0.27

522 0.105 Unpaved 0.03

Length (ft)
Slope (ft/ft)
n-value Flow
Area (ftz)
Wetted Perimeter (ft)
Tt (hrs)
636 0.028 0.065 2.0 4.0 0.07

Post-development T~ = 0.37 hrs (Minimum 5minutes)
Wake County Stormwater Tool
Version 2.0
7~
10/9/2007 10:41 AM

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~~ Stormwater Management Plan SID No.:
Norwood Tract Date: 9/21/2007
COUNTY Withers & Ravenel Designer: SAH
N[>ATli fA.Ri34.t 3vJ1
PEAK FLOW CALCULATIONS
(CURVE NUMBER:
Pre-development CN = 58
Post-Development CNad~ = 58
TIME OF CONCENTRATION:
Pre-development T~ = 0.37 hrs
Post-development T~ = 0.37 hrs
PEAK FLOW:
Method: TR-55 Graohical Peak Discharge Method for Type II Distribution
QP = q~AmQ*
Where:
Qp =Peak Discharge (cfs)
q„ =Unit peak discharge (csm/in) TR-55 Appendix F
Am =Drainage Area (miz)
Q` =runoff (inches)
Pre-development
q„ = 266.77 csm/in
Am = 0.05 mil
Q` = 0.27 inches
Q~-year = 3.49 Cfs
Post-development
q„ = 266.77 csm/in
Am = 0.05 miz
Q* = 0.27 inches
Q~-year = 3.49 Cfs
Wake County Stormwater Tool
Version 2.0
-~; l
r~~'
10/9/2007 10:41 AM

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~ ~~ Stormwater Management Plan SID No.:
Norwood Tract Date: 9/21/2007
COUNTY Withers & Ravenel Designer: SAH
..~ ~nria r.racai.~4a
PROPOSED STORAGE DEVICES
Storage Volume
Name/Location T pe of Device Provided (ft3) Additional Comments
1 BMP 1 D Detention Basin 13574 Southern BMP
2 BMP 2 D Detention Basin 15285 Northern BMP
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Total Volume Provided: 28859 ft
Volumes ou a increase y: c.. --~ N~ ~ t4c ~' ''~~~ ~-- V °~~'`'~~
Volume Required by Wake '~~~u'~~= ~~, ~~ w
County Ordinance: 12423 ft3 ~E-rE~~-no~~ Mc-7,
,;STI r+„~TEq
imuln Volume Required to Meet Peak
Flows for Neuse Rules: 17637 ft3
Total Volume Required: 30060 ft
Post-Development Curve Number Adjustment based on Volume Provided
Source: "Modeling Infiltration Practices Using TR-20", October, 1983, Maryland Department of the Environment
200
Chad, _ (P+2Q+2) - (5PQ+4Qz)vz
Where:
P =Rainfall (inches) = 3 inches
Q =Runoff Depth for Proposed CN (Q') -Volume Provided (inches)
Volume Provided (Inches) = 0.26 inches
Q* = 0.54 inches
Q = 0.28 inches
Post-Development CNadj = 58
Wake County Stormwater Too-
Version 2.0
~i~
10/9/2007 10:41 AM

Stormwater Management Plan ~s/D No.:
'W~~.[~E Norwood Tract Date:
COUNTY Withers & Ravenel Designe
\S?A,YId C.AR<?FlU.a
NITROGEN CALCULATIONS
TN export TN export
coefficient from use
T e of Land Cover Area (acres) (Ibs/ac/yr) Ibs/ r
Permanently protected undisturbed open
space (forest, unmown meadow) 14.84 0.60 8.90
Permanently protected managed open
space ( rass, landsca ing, etc.) 10.76 1.20 12.91

Impervious surfaces (roads, parking lots,
drivewa s, roofs, etc.) 4.96 21.20 105.20
TOTAL 30.56 127.02
9/21 /2007
SAH
Nitrogen Loading w/out BMP Reductions: 4.16 Ibs/ac/yr
Neuse Buy-down w/out BMP Reductions: $5,647.49 (Before sn/o7) $14,555:12 cAners/1ro~y
Nitrogen Loading with BMP Reductions
See Wake County Stormwater Design Manual Chapter 4 for Details
o Arnim 1•
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T pe of Land Cover

Area (acres)
TN coeff.
(Ibs/ac/yr)
TN export
Ibs/ r
Permanent) rotected opens ace 0.60 0.60 0.36
Managed open space 6.40 1.20 7.68
Im envious surfaces 1.50 21.20 31.80
TOTAL 8.50 39.84
Nitrogen Removal Efficiency of BMP(s) 1ti
Nitrogen Loading for DA 1: 3.37 Ibs/ac/yr
Drainage Area 2:

T e of Land Cover
Area (acres) TN coeff.
(Ibs/ac/yr) TN export
Ibs) r
Permanent) rotected o en space 0.60
Mana ed o ens ace 0.70 1.20 0.84
Im envious surfaces 0.10 21.20 2.12
TOTAL 0.80 2.96
Nitrogen Removal Efficiency or BnnN(sl ~/ ro
Nitrogen Loading for DA 2: 2.33 Ibs/ac/yr
Drainage Area 3:

T e of Land Cover
Area (acres) TN coeff.
(Ibs/ac/yr) TN export
Ibs/ r
Permanent) rotected o ens ace 0.60
Managed opens ace 1.20
Im envious surfaces 21.20
TOTAL
Nitrogen Removal Efficiency of BMP(s)
Nitrogen Loading for DA 3:
~~0
Ibs/ac/yr
Final Nitrogen Loading from Site: 3.75 Ibs/ac/yr
Wake County Stormwater Tool ; -=
„_._:__ ., „ f I p~ 10/9/2007 10:41 AM

Buy-down (Neuse Only) BEFORE September 1, 2007: $1,512.72
Wake County Stormwater Tool ~ ~
Version 2.0 10/9/2007 10:41 AM

Detention Pond Calculations
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Hydrograph Summary Report (~'~~
Hydraflow Hydrographs by Intelisolve v9.1
Hyd.
No. Hydrograph
type
(origin) Peak
flow
(cfs) Time
interval
(min) Time to
peak
(min) Hyd.
volume
(cult) Inflow
hyd(s) Maximum
elevation
(ft) Total
strge used
(cult) Hydrograph
description
1 SCS Runoff 5.518 1 719 13,771 ---- ---- ---- Pond #1 Pre-Developed
2 SCS Runoff 7.606 1 718 17,335 --- --- -- Pond #1 Post-Developed
3 Reservoir 0.140 1 1429 10,527 2 385.50 13,588 Pond #1 Routing
4 SCS Runoff 0.519 1 719 1,296 -- --- ------ Pond #2 Pre-Developed
5 SCS Runoff 0.716 1 718 1,632 -- -- ---- Pond #2 Post-Developed
6 Reservoir 0.025 1 958 1,597 5 358.24 811 Pond #2 Routing
POND.gpw Return Period: 1 Year Tuesday, Oct 9, 2007
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Hydrograph Summary Report (o-~
Hydraflow Hydrographs by Intelisolve v9.1
Hyd.
No. Hydrograph
type
(origin) Peak
flow
(cfs) Time
interval
(min) Time to
peak
(min) Hyd.
volume
(tuft) Inflow
hyd(s) Maximum
elevation
(ft) Total
strge used
(tuft) Hydrograph
description
1 SCS Runoff 27.57 1 718 55,836 ---- --- ---- Pond #1 Pre-Developed
2 SCS Runoff 31.50 1 718 63,362 --- --- --- Pond #1 Post-Developed
3 Reservoir 26.96 1 720 56,535 2 385.95 16,509 Pond #1 Routing
4 SCS Runoff 2.594 1 718 5,255 ---- ---- -- Pond #2 Pre-Developed
5 SCS Runoff 2.964 1 718 5,963 -- ------ Pond #2 Post-Developed
6 Reservoir 0.060 1 1035 5,589 5 359.10 3,783 Pond #2 Routing
POND.gpw Return Period: 10 Year Tuesday, Oct 9, 2007
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Hydrograph Summary Report ~~~-y~°
Hydraflow Hydrographs by Intelisolve v9.1
Hyd.
No. Hydrograph
type
(origin) Peak
flow
(cfs) Time
interval
(min) Time to
peak
(min) Hyd.
volume
(cult) Inflow
hyd(s) Maximum
elevation
(ft) Total
strge used
(cult) Hydrograph
description
1 SCS Runoff 58.03 1 718 116,733 --- ------ ---- Pond #1 Pre-Developed
2 SCS Runoff 63.11 1 718 127,518 - -- Pond #1 Post-Developed
3 Reservoir 62.46 1 718 120,681 2 386.49 18,407 Pond #1 Routing
4 SCS Runoff 5.461 1 718 10,987 --- --- ---- Pond #2 Pre-Developed
5 SCS Runoff 5.940 1 718 12,002 - -- --- Pond #2 Post-Developed
6 Reservoir 0.087 1 1127 9,609 5 360.21 8,537 Pond #2 Routing
POND.gpw Return Period: 100 Year Tuesday, Oct 9, 2007
U

DRY DETENTION POND #1 ORIFICE SIZING
Detention Volume 13,574 cf
13,574 cf X
48 hr
Q=0.6*Area(2(32.2)(Have))^0.5
Area 1.918 sq in
Orifice Diameter 1.56 in
1 hr =
3600 sec
Have 1.5 ft
0.0786 cfs
13,574 cf X 1 hr =
120 hr 3600 sec
Q=0.6*Area(2(32.2)(Have))"0.5 Have 1.5 ft
Area 0.767 in^2
Orifice Diameter 0.99 in
0.0314 cfs
Use Orifice Diameter 1.5 in BMP Outflow 0.29 cfs
~~~

Pond Report
Hydraflow Hydrographs by Intelisolve v9.1 Friday, Oct 5, 2007
- POND #1
Pond Data
Contours -User-defined contour areas. Conic method used for volume calculation. Begining Elevation = 383.00 ft
Stage /Storage Table
Stage (ft) Elevation (ft) Contour area (sgft) Incr. Storage (tuft) Total storage (tuft)
0.00 383.00 4,549 0 0
1.00 384.00 5,229 4,885 4,885
2.00 385.00 5,947 5,584 10,468
!
~~ }'
~
~~ ~
~ ~J rx ~
O F
2.50 385.50 6,480 3,105 ~
13,574 o - , ,
3.00 386.00 6,708 3,297 16,870 ) ~ ~-~ ~ ~ F {~Q~E G TU
4.00 387.00 713 3,202 20,072 .~
Culvert /Orifice Structures Weir Structures
[A] [B] [C] [PrfRsr] [A] [B] [C] [D]
Rise (in) = 18.00 1.50 0.00 0.00 Crest Len (ft) = 16.00 15.00 0.00 0.00
Span (in) = 18.00 1.50 0.00 0.00 Crest EI. (ft) = 385.50 385.'0 0.00 0.00
No. Barrels = 1 1 0 0 Weir Coeff. = 3.33 3.33 3.33 3.33
Invert EI. (ft) = 383.00 383.00 0.00 0.00 Weir Type =Riser Rect -- -
Length (ft) = 33.00 0.00 0.00 0.00 Multi-Stage =Yes No No No
Slope (%) = 3.03 0.00 0.00 n/a
N-Value = .013 .013 .013 n/a
Orifice Coeff. = 0.60 0.60 0.60 0.60 Exfil.(in/hr) = 0.000 (by Wet area)
Multi-Stage = n/a Yes No No TW Elev. (ft) = 0.00
Note: CulverUOrifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s).
Stage I Storage I Discharge Table
Stage Storage Elevation Clv A Clv B Clv C PrfRsr Wr A Wr B Wr C Wr D Exfil User Total
ft tuft ft cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs
0.00 0 383.00 0.00 0.00 - - 0.00 0.00 -- - -- -- 0.00
1.00 4,885 384.00 0.06 is 0.06 is - - 0.00 0.00 - - - - 0.06
2.00 10,468 385.00 0.08 is 0.08 is - - 0.00 0.00 - - - - 0.08
2.50 13,574 385.50 0.09 is 0.09 is - - 0.00 0.00 - - - -- 0.09
3.00 16,870 386.00 12.42 is 0.02 is - - 12.40 s 17.66 - - - - 30.08
4.00 20,072 387.00 15.32 is 0.01 is - - 15.26 s 91.76 - - - -- 107.03
17

DRY DETENTION POND #2 ORIFICE SIZING
Detention Volume 11,422 cf
Orifice Size for 2 Day Drawdown
11,422 cf X
48 hr
Q=0.6*Area(2(32.2)(Have))^0.5
Area 1.614 sq in
Orifice Diameter 1.43 in
1 hr =
3600 sec
Have 1.5 ft
0.0661 cfs
11,422 cf X
120 hr
Q=0.6*Area(2(32.2)(Have))^0.5
Area 0.646 in"2
Orifice Diameter 0.91 in
1 hr =
3600 sec
Have 1.5 ft
0.0264 cfs
Use Orifice Diameter 1.5 in BMP Outflow 0.29 cfs
~t

Pond Report
Hydraflow Hydrographs by Intelisolve v9.1 Tuesday, Oct 9, 2007
Pond No. 1 -Pond #2
Pond Data
Contours -User-defined contour areas. Conic method used for volume calculation. Begining Elevation = 358.00 ft
Stage /Storage Table
Stage (ft) Elevation (ft) Contour area (sgft) Incr. Storage (cult) Total storage (cult)
0.00
1.00
2.00
3.00
3.50
4.00
5.00 358.00
359.00
360.00
361.00
361.50
362.00
363.00 2,993
3,739
4,545
5,412
5,869
6,340
7,329 0
3,359
4,135
4,972
2,819
3,051
6,828 0
3,359
7,494
12,465 c~ ~Uti4 ~ 2 ~o~v~/tE aF
15,285
18,336 l S~ZPs cF L~40UE~ TO
25,164 ~1~~-~~''~ ~~'uteC~'~
Culvert /Orifice Structures Weir Structures
Ip-] IBI [C] IPrfRsr] IAl IB] , [Cl ID]
Rise (in) = 18.00 1.50 0.00 0.00 Crest Len (ft) = 12.00 10.00 0.00 0.00
Span (in) = 18.00 1.50 0.00 0.00 Crest EI. (ft) = 361.50 361.70 0.00 0.00
No. Barrels = 1 1 0 0 Weir Coeff. = 3.33 3.33 3.33 3.33
Invert EI. (ft) = 358.00 358.00 0.00 0.00 Weir Type =Riser Rect - -
Length (ft) = 38.00 0.00 0.00 0.00 Multi-Stage =Yes No No No
Slope (%) = 0.50 0.00 0.00 n/a
N-Value = .013 .013 .013 n/a
Orifice Coeff. = 0.60 0.60 0.60 0.60 Exfil.(iNhr) = 0.000 (by Wet area)
Multi-Stage = n/a No No No TW Elev. (ft) = 0.00
Note: CulverUOrifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s).
Stage /Storage /Discharge Table
Stage Storage Elevation Clv A Clv B Clv C PrfRsr Wr A Wr B Wr C Wr D Exfil User Total
ft cult ft cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs
0.00 0 358.00 0.00 0.00 - -- 0.00 0.00 - -- -- -- 0.00
1.00 3,359 359.00 0.00 0.06 is - - 0.00 0.00 - - - - 0.06
2.00 7,494 360.00 0.00 0.08 is - -- 0.00 0.00 -- - - - 0.08
3.00 12,465 361.00 0.00 0.10 is - -- 0.00 0.00 - - - - 0.10
3.50 15,285 361.50 0.00 0.11 is - -- 0.00 0.00 - - - -- 0.11
4.00 18,336 362.00 14.12 is 0.12 is - -- 14.12 s 5.47 - - -- - 19.71
5.00 25,164 363.00 17.49 is 0.13 is - - 17.46 s 49.36 - - - -- 66.95
l `i

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TR55 Tc Worksheet
Hyd. No. 1 (~P~N~~~-:..i ~ ~
Pre-Developed t -
Description A
Sheet Flow
Manning's n-value = 0.011
Flow length (ft) = 100.0
Two-year 24-hr precip. (in) = 3.60
Land slope (%) = 4.00
Travel Time (min) = 0.87
Shallow Concentrated Flow
Flow length (ft) = 600.00
Watercourse slope (%) = 9.60
Surface description =Unpaved
Average velocity (ft/s) = 5.00
Travel Time (min) = 2.00
Channel Flow
B C
0.011 0.011
0.0 0.0
0.00 0.00
0.00 0.00
+ 0.00 + 0.00
Hydraflow Hydrographs by Intelisolve v9.1
Totals
= 0.87
0.00 0.00
0.00 0.00
Paved Paved
0.00 0.00
+ 0.00 + 0.00 = 2.00
X sectional flow area (sgft) = 0.00 0.00 0.00
Wetted perimeter (ft) = 0.00 0.00 0.00
Channel slope (%) = 0.00 0.00 0.00
Manning's n-value = 0.015 0.015 0.015
Velocity (ft/s) = 0.00 0.00 0.00
Flow length (ft) = 0.0 0.0 0.0
Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00
Total Travel Time, Tc .................................................. ....................... ..... 2.87 min
~----
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Minor Flood Study:
FES-2 -Outlet-1
2c

Culvert Designer/Analyzer Report
• FES-2 -OUTLET-1
• ~~25~
• Analysis Component
Storm Event Design Discharge 26.75 cfs
Peak Discharge Method: Rational
Design Retum Period 25 year Check Return Period 100 year
• Design Peak Discharge 26.75 cfs Check Peak Discharge 31.74 cfs
• Total Area 8.10 acres Time of Concentration 5.00 min
Rational Coefficient 0.40 Intensity 9.72 in/hr
• Area
Subwatershed(acres) C
• 1 8.10 0.40
•
• Tailwater Conditions: Constant Tailwater
Tailwater Elevation N/A ft
• Name Description Discharge HW Elev. Velocity
• Culvert-1 1-24 inch Circular 26.75 cfs 390.18 ft 14.12 ft/s
Weir Not Considered N/A N/A N/A

•

• Title: CHATSWORTH Project Engineer. MLS
• k:\...\proj\stormwaterlculverts.cvm Withers 8 Ravenel CulvertMaster v3.0 [3.0004)
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Culvert Designer/Analyzer Report
FES-2 -OUTLET-1
Component:Culvert-1 ~ ~ ~ ~~
Culvert Summary
Computed Headwater Elev. 390.18 ft Discharge 26.75 cfs
Inlet Control HW Elev. 390.18 ft Tailwater Elevation N/A ft
Outlet Control HW Elev. 389.68 ft Control Type Inlet Control
Headwater Depth/Height 2.09

Grades
Upstream Invert 386.00 ft Downstream Invert 382.00 ft
Length 66.00 ft Constructed Slope 0.043956 ft/ft

Hydraulic Profile
Profile S2 Depth, Downstream 1.16 ft
Slope Type Steep Normal Depth 1.07 ft
Flow Regime Supercritical Critical Depth 1.80 ft
Velocity Downstream 14.12 ft/s Critical Slope 0.012292 ft!ft

Section
Section Shape Circular Mannings Coefficient 0.013
Section Material Concrete Span 2.00 ft
Section Size 24 inch Rise 2.00 ft
Number Sections 1

Outlet Control Properties
Outlet Control HW Elev. 389.68 ft Upstream Velocity Head 1.25 ft
Ke 0.50 Entrance Loss 0.63 ft

Inlet Control Properties
Inlet Control HW Elev. 390.18 ft Flow Control Submerged
Inlet Type Square edge w/headwall Area Full 3.1 ftz
K 0.00980 HDS 5 Chart 1
M 2.00000 HDS 5 Scale 1
C 0.03980 Equation Form 1
Y 0.67000
Titte: CHATSWORTH Project Engineer: MLS
k:\...\projlstormwaterlculverts.cvm Withers 8 Ravenel CulvertMaster v3.0 [3.0004]
09/20/07 11:22:47 AM ©Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 USA [phone] Page 2 of 2
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Culvert Designer/Analyzer Report
FES-2 -OUTLET-1
(~-~a~'1
Analysis Component
Storm Event Check Discharge 31.74 cfs

Peak Discharge Method: Rational
Design Return Period 25 year Check Return Period 100 year
Design Peak Discharge 26.75 cfs Check Peak Discharge 31.74 cfs
Total Area 8.10 acres Time of Concentration 5.00 min
Rational Coefficient 0.40 Intensity 9.72 in/hr
Area
Subwatershed(acres) C
1 8.10 0.40
Tailwater Conditions: Constant Tailwater
Tailwater Elevation N/A ft
Name Description Discharge HW Elev. Velocity
Culvert-1 1-24 inch Circular 31.74 cfs 391.36 ft 14.69 ft/s
Weir Not Considered N/A N/A N/A
Title: CHATSWORTH Project Engineer: MLS
k:\...\proj\stomtwater\culverts.cvm Withers & Ravenel CulvertMaster v3.0 [3.0004]
09/20/07 11:22:38 AM ©Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 USA [phone] Page 1 of 2
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Culvert Designer/Analyzer Report
FES-2 -OUTLET-1
Component:Culvert-1
Q~
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Culvert Summary
Computed Headwater Elevs
Inlet Control HW Elev. 391.36 ft
391.36 ft Discharge
Tailwater Elevation 31.74 cfs
N/A ft
Outlet Control HW Elev. 390.38 ft Control Type Inlet Control
Headwater Depth/Height 2.68

Grades
Upstream Invert
Length 386.00 ft
66.00 ft Downstream Invert
Constructed Slope 382.00 ft
0.043956 ft/ft

Hydraulic Profile
Profile
Slope Type
Flow Regime
Velocity Downstream S2
Steep
Supercritical
14.69 ft/s Depth, Downstream
Normal Depth
Critical Depth
Critical Slope 1.30 ft
1.20 ft
1.89 ft
0.017026 ft/ft

Section
Section Shape
Section Material
Section Size Circular
Concrete
24 inch Mannings Coefficient
Span
Rise 0.013
2.00 ft
2.00 ft
Number Sections 1

Outlet Control Properties
Outlet Control HW Elev.
Ke 390.38 ft
0.50 Upstream Velocity Head 1.66 ft
Entrance Loss 0.83 ft

Inlet Control Properties
Inlet Control HW Etev. 391.36 ft
Inlet Type Square edge w/headwall
K 0.00980
M 2.00000
C 0.03980 Flow Control
Area Full
HDS 5 Chart
HDS 5 Scale
Equation Form Submerged
3.1 ft=
1
1
1
y 0.67000
Project Engineer: MLS
Title: CHATSWORTH CulvertMaster v3.0 [3.0004]
k:\...\proj~stormwater\culverts.cvm Withers 8 Ravenel
09/20/07 11:22:38 AM ®Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 USA [phone] Page 2 of 2

Minor Flood Study:
I3W-4 - HW-3
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Culvert Designer/Analyzer Report
HW-4 - HW-3
~-25~
Analysis Component
Storm Event Design Discharge 75.95 cfs

Peak Discharge Method: Rational
Design Return Period 25 year Check Return Period 100 year
Design Peak Discharge 75.95 cfs Check Peak Discharge 90.14 cfs
Total Area 23.00 acres Time of Concentration 5.00 min
Rational Coefficient 0.40 Intensity 9.72 in/hr
Area
Subwatershed(acres) C
1 23.00 0.40
Tailwater Conditions: Constant Tailwater
Tailwater Elevation N/A ft
Name Description Discharge HW Elev. Velocity
Culvert-1 1-48 inch Circular 75.95 cfs 362.38 ft 15.39 ft!s
Weir Not Considered N/A N/A N/A
Title: CHATSWORTH Project Engineer: MLS
k:\...\proj\stormwater\culverts.cvm Withers 8 Ravenel CulvertMaster v3.0 [3.0004]
08/15/07 09:14:04 AM ©Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 USA [phone] Page 1 of 2
CZ~~

Culvert Designer/Analyzer Report
HW-4 - HW-3
Component:Culvert-1 ~ ~ ~~~
Culvert Summary
Computed Headwater Elew 362.38 ft Discharge 75.95 cfs
Inlet Control HW Elev. 362.09 ft Tailwater Elevation N/A ft
Outlet Control HW Elev. 362.38 ft Control Type Entran ce Control
Headwater Depth/Height 1.09

Grades
Upstream Invert 358.00 ft Downstream Invert 355.00 ft
Length 97.00 ft Constructed Slope 0.030928 ft/ft

Hydraulic Profile
Profile S2 Depth, Downstream 1.66 ft
Slope Type Steep Normal Depth 1.50 ft
Flow Regime Supercritical Critical Depth 2.64 ft
Velocity Downstream 15.39 ft/s Critical Slope 0.004689 ft/ft

Section
Section Shape Circular Mannings Coefficient 0.013
Section Material Concrete Span 4.00 ft
Section Size 48 inch Rise 4.00 ft
Number Sections 1

Outlet Control Properties
Outlet Control HW Elev. 362.38 ft Upstream Velocity Head 1.16 ft
Ke 0.50 Entrance Loss 0.58 ft

Inlet Control Properties
Inlet Control HW Elev. 362.09 ft Flow Control N/A
Inlet Type Square edge w/headwall Area Full 12.6 ft2
K 0.00980 HDS 5 Chart 1
M 2.00000 HDS 5 Scale 1
C 0.03980 Equation Form 1
Y 0.67000
Title: CHATSWORTH Project Engineer: MLS
k:\...\proj\stormwater\culverts.cvm Withers 8 Ravenel CulvertMaster v3.0 [3.0004]
08/15/07 09:14:04 AM ©Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 USA [phone] Page 2 of 2
~~

~ Culvert Designer/Analyzer Report
• H
W-4 - HW-3
/
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• Analysis Component
Storm Event Check Discharge ~ 90.14 cfs

Peak Discharge Method: Rational
.
Design Return Period 25 year Check Return Period 100 year
• Design Peak Discharge 75.95 cfs Check Peak Discharge 90.14 cfs
• Total Area 23.00 acres Time of Concentration 5.00 min
Rational Coefficient 0.40 Intensity 9.72 in/hr

• Area
Subwatershed(acres) C
• 1 23.00 0.40

• Tailwater Conditions: Constant Tailwater
Tailwater Elevation N/A ft

• Name Description Discharge HW Elev. Velocity
• Culvert-1 1-48 inch Circular 90.14 cfs 362.90 ft 15.94 ft/s
Weir Not Considered N/A N/A N/A
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. Title: CHATSWORTH Project Engineer: MLS
. k:\...\proj\stormwater\culverts.cvm Withers 8 Ravenel CulvertMaster v3.0 [3.0004]
08/15/07 09:14:56 AM ©Haestad Waterbury, CT 06708 USA [phone] Page 1 of 2
Methods, Inc. 37 Brookside Road
• ~
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~ Culvert Designer/Analyzer Report
~ HW-4 - HW-3
• ~ -, ~ ~~
Component:Culvert-1 \

• Culvert Summary
Computed Headwater Elev< 362.90 ft Discharge 90.14 cfs
• Inlet Control HW Elev. 362.68 ft Tailwater Elevation N/A ft
• Outlet Control HW Elev. 362.90 ft Control Type Entrance Control
Headwater Depth/Height 1.22

• Grades
• Upstream Invert 358.00 ft Downstream Invert 355.00 ft
Length 97.00 ft Constructed Slope 0.030928 ft/ft
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Hydraulic Profile
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Profile S2 Depth, Downstream 1.84 ft
• Slope Type Steep Normal Depth 1.65 ft
• Flow Regime Supercritical Critical Depth 2.88 ft
Velocity Downstream 15.94 fUs Critical Slope 0.005233 ft/ft
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Section
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Section Shape Circular Mannings Coefficient 0.013
• Section Material Concrete Span 4.00 ft
Section Size 48 inch Rise 4.00 ft
Number Sections 1

• Outlet Control Properties
Outlet Control HW Elev. 362.90 ft Upstream Velocity Head 1.35 ft
• Ke 0.50 Entrance Loss 0.67 ft

•
Inlet Control Properties
• Inlet Control HW Elev. 362.68 ft Flow Control Transition
• Inlet Type Square edge w/headwall Area Full 12.6 ft2
K 0.00980 HDS 5 Chart 1
• M 2.00000 HDS 5 Scale 1
• C 0.03980 Equation Form 1
Y 0.67000
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• Title: CHATSWORTH Project Engineer: MLS
• k:\...\proj\stormwater\culverts.cvm Withers 8 Ravenel CulvertMaster v3.0 [3.0004]
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08/15/07 09:14:56 AM ©Hae stad Methods, I age
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Roadside Ditch Calculations
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11+00 - 14+00 RIGHT
Project Description....
Friction Method Manning Formula
Solve For Normal Depth
Input :Data
Roughness Coefficient
Channel Slope
Left Side Slope
Right Side Slope
Discharge
Results
Normal Depth
Flow Area
Wetted Perimeter
Top Width
Critical Depth
Critical Slope
Velocity
Velocity Head
Specific Energy
Froude Number
Flow Type
GVF Input.Data
Downstream Depth
Length
Number Of Steps
GVF Olatput Data
Upstream Depth
Profile Description
Profile Headloss
Downstream Velocity
Upstream Velocity
Normal Depth
Critical Depth
Channel Slope
Critical Slope
0.025
0.09800 ft/ft
4.00 ft/ft (H:V)
3.00 ft/ft (H:V)
11.55 ft'/s
0.63 ft
1.38 ft2
4.57 ft
4.40 ft
0.93 ft
0.01242 ft/ft
8.37 ft/s
1.09 ft
1.72 ft
2.63
Supercritical
0.00 ft
0.00 ft
0
0.00 ft
0.00 ft
Infinity ft/s
Infinity ft/s
0.63 ft
0.93 ft
0.09800 ft/ft
0.01242 ft/ft
Bentley Systems, Inc. Haestad Methods Solution Center FlowMaster [08.01.058.00]
8116!2007 9:33:54 AM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA [phone] Page 1 of 1
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Worksheet for 14+00 - 15+50 R
Project Description
Friction Method
Solve For
Input Data
Roughness Coefficient
Channel Slope
Left Side Slope
Right Side Slope
Discharge
Results
Normal Depth
Flow Area
Wetted Perimeter
Top Width
Critical Depth
Critical Slope
Velocity
Velocity Head
Specific Energy
Froude Number
Flow Type
GVF InputData
Downstream Depth
Length
Number Of Steps
GVF Output Data
Upstream Depth
Profile Description
Profile Headloss
Downstream Velocity
Upstream Velocity
Normal Depth
Critical Depth
Channel Slope
Critical Slope
8/16I200T 10:16:46 AM
Manning Formula
Normal Depth
0.028
0.02000 ft/ft
4.00 ft/ft (H:V)
3.00 ft/ft (H:V)
6.93 ft'/s
0.73 ft
1.86 ft2
5.31 ft
5.10 ft
0.75 ft
0.01668 ft/ft
3.73 ft/s
0.22 ft
0.94 ft
1.09
Supercritical
0.00 ft
0.00 ft
0
0.00 ft
0.00 ft
Infinity ft/s
Infinity ff/s
0.73 ft
0.75 ft
0.02000 ft/ft
0.01668 ft!ft
Bentley Systems, Inc. Haestad Methods Solution Center FlowMaster [08.01.058.00]
27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA [phone] Page 1 of 1
,~3

Worksheet for 16+00 - 18+00 R
Project Description
Friction Method Manning Formula
Solve For Normal Depth
Input.Data
Roughness Coefficient 0.028
Channel Slope 0.02500 ft/ft
Left Side Slope 4.00 ft/ft (H:V)
Right Side Slope 3.00 ft/ft (H:V)
Discharge 3.47 ft'/s
Results
Normal Depth 0.54 ft
Flow Area 1.02 ft:
Wetted Perimeter 3.93 ft
Top Width 3.77 ft
Critical Depth 0.57 ft
Critical Slope 0.01829 ft/ft
Velocity 3.41 ft/s
Velocity Head 0.18 ft
Specific Energy 0.72 ft
Froude Number 1.16
Flow Type Supercritical
GVF Input Data
Downstream Depth 0.00 ft
Length 0.00 ft
Number Of Steps 0
GVF Output Data
Upstream Depth 0.00 ft
Profile Description
Profile Headloss 0.00 ft
Downstream Velocity Infinity ft/s
Upstream Velocity Infinity ft/s
Normal Depth 0.54 ft
Critical Depth 0.57 ft
Channel Slope 0.02500 ft/ft
Critical Slope 0.01829 ft/ft
Bentley Systems, Inc. Haestad Methods Solution Center FlowMaster (08.01.058.00]
8/15/2007 10:18:19 AM 27 Siemons Company Drive Suite 200 W WateRown, CT 06795 USA [phone] Page 1 of 1

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Worksheet for 19+00 - 21 +00 R
Project Description
Friction Method Manning Formula
Solve For Normal Depth
Input Data
Roughness Coefficient 0.040
Channel Slope 0.09800 ft/ft
Left Side Slope 4.00 ft/ft (H:V)
Right Side Slope 3.00 ft/ft (H:V)
Discharge 0.87 ft'/s
Results
Normal Depth 0.28 ft
Flow Area 0.28 ft~
Wetted Perimeter 2.07 f{
Top Width 1.99 ft
Critical Depth 0.33 ft
Critical Slope 0.04489 ft/ft
Velocity 3.08 ft/s
Velocity Head 0.15 ft
Specific Energy 0.43 ft
Froude Number 1.44
Flow Type Supercritical
GVF Input. Data
Downstream Depth 0.00 ft
Length 0.00 ft
Number Of Steps 0
GVF Output Data
Upstream Depth 0.00 ft
Profile Description
Profile Headloss 0.00 ft
Downstream Velocity Infinity ft/s
Upstream Velocity Infinity fUs
Normal Depth 0.28 ft
Critical Depth 0.33 ft
Channel Slope 0.09800 ft/ft
Critical Slope 0.04489 ft/ft
Bentley Systems, Inc. Haestad Methods Solution Center FlowMaster [08.01.058.00]
8/1612007 10:39:22 AM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA [phone] Page 1 of 1
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Worksheet for 11 +00 - 12+00 L
Project Description
Friction Method
Solve For
Input Data
Roughness Coefficient
Channel Slope
Left Side Slope
Right Side Slope
Discharge
Results
Normal Depth
Flow Area
Wetted Perimeter
Top Width
Critical Depth
Critical Slope
Velocity
Velocity Head
Specific Energy
Froude Number
Flow Type
GVF Input Data
Downstream Depth
Length
Number Of Steps
GVF Output Data
Upstream Depth
Profile Description
Profile Headloss
Downstream Velocity
Upstream Velocity
Normal Depth
Critical Depth
Channel Slope
Critical Slope
Manning Formula
Normal Depth
0.041
0.09800 ft/ft
4.00 ft/ft (H:V)
3.00 ft/ft (H:V)
0.43 fN/s
0.22 ft
0.17 ft=
1.60 ft
1.54 ft
0.25 ft
0.05181 ft/ft
2.54 ft/s
0.10 ft
0.32 ft
1.35
Supercritical
0.00 ft
0.00 ft
0
0.00 ft
0.00 ft
Infinity ft/s
Infinity ff/s
0.22 ft
0.25 ft
0.09800 ft/ft
0.05181 ft/ft
Bentley Systems, Inc. Haestad Methods Solution Center FlowMaster [08.01.058.00]
81181200711:11:02 AM 27 Siemons Company Drive Suite 200 W WateRown, CT 08795 USA [phone] Page 1 of 1
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Worksheet for 14+00 - 14+75 L
Project Description
Friction Method
Solve For
Input Data
Roughness Coefficient
Channel Slope
Left Side Slope
Right Side Slope
Discharge
Results
Normal Depth
Flow Area
Wetted Perimeter
Top Width
Critical Depth
Critical Slope
Velocity
Velocity Head
Specific Energy
Froude Number
Flow Type
GVF Input Data
Downstream Depth
Length
Number Of Steps
GVF Output Data
Upstream Depth
Profile Description
Profile Headioss
Downstream Velocity
Upstream Velocity
Normal Depth
Critical Depth
Channel Slope
Critical Slope
Manning Formula
Normal Depth
0.055
0.02000 ft/ft
4.00 ft/ft (H:V)
3.00 ft/ft (H:V)
0.43 ft'/s
0.33 ft
0.38 ft=
2.41 ft
2.32 ft
0.25 ft
0.09323 ft/ft
1.12 ft/s
0.02 ft
0.35 ft
0.49
Subcritical
0.00 ft
0.00 ft
0
0.00 ft
0.00 ft
Infinity ft/s
Infinity ft/s
0.33 ft
0.25 ft
0.02000 ft/ft
0.09323 ft/ft
Bentley Systems, Inc. Haestad Methods Solution Center FlowMaster [08.01.058.00]
8/16/2007 11:13:12 AM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA [phone] Page 1 of 1
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Worksheet for 16+50 - 18+00 L
Project. Description
Friction Method
Solve For
Input Data
Roughness Coefficient
Channel Slope
Left Side Slope
Right Side Slope
Discharge
Results
Normal Depth
Flow Area
Wetted Perimeter
Top Width
Critical Depth
Critical Slope
Velocity
Velocity Head
Specific Energy
Froude Number
Flow Type
GVF Input Data
Downstream Depth
Length
Number Of Steps
GVF Output Data
Upstream Depth
Profile Description
Profile Headloss
Downstream Velocity
Upstream Velocity
Normal Depth
Critical Depth
Channel Slope
Critical Slope
Manning Formula
Normal Depth
0.055
0.02400 ft/ft
4.00 ft/ft (H:V)
3.00 ft/ft (H:V)
0.43 ft'/s
0.32 ft
0.36 ft:
2.33 ft
2.24 ft
0.25 ft
0.09323 ft/ft
1.20 ft!s
0.02 ft
0.34 ft
0.53
Subcritical
0.00 ft
0.00 ft
0
0.00 ft
0.00 ft
Infinity ft/s
Infinity ft/s
0.32 ft
0.25 ft
0.02400 ft/ft
0.09323 ft/ft
Bentley Systems, Inc. Haestad Methods Solution Center FlowMaster [08.01.058.00]
8/16/2007 11:14:00 AM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA [phone] Page 1 of 1
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Worksheet for 19+00 - 20+75 L
Project Description
Friction Method Manning Formula
Solve For Normal Depth
Input Data
Roughness Coefficient 0.041
Channel Slope 0.09800 ft!ft
Left Side Slope 4.00 ft/ft (H:V)
Right Side Slope 3.00 ft/ft (H:V)
Discharge 0.87 ft /s
Results
Normal Depth 0.29 ft
Ffow Area 0.29 ft2
Wetted Perimeter 2.09 ft
Top Width 2.01 ft
Critical Depth 0.33 ft
Critical Slope 0.04716 ft/ft
Velocity 3.03 fUs
Velocity Head 0.14 ft
Specific Energy 0.43 ft
Froude Number 1.41
Flow Type Supercritical
GVF Input Data
Downstream Depth 0.00 ft
Length 0.00 ft
Number Of Steps 0
GVF Output Data
Upstream Depth 0.00 ft
Profile Description
Profile Headloss 0.00 ft
Downstream Velocity Infinity ft/s
Upstream Velocity Infinity ft/s
Normal Depth 0.29 ft
Critical Depth 0.33 ft
Channel Slope 0.09800 ft/ft
Critical Slope 0.04716 ft/ft
Bentley Systems, Inc. Haestad Methods Solution Center FlowMaster [09.01.058.00]
SH5/2007 11:11:57 AM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA [phone] Page 1 of 1
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