20070208 Ver 2_More Info Received_20071203

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CLH desi n .a. o7-a~$~a
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MacGregor Park, 125 Ea'inburgh South, Suite 310
Cary, North Carolina 27511
Phone.• (9I9) 319-6716 Fax.• (9I9) 319-7516
30-Nov-07
TO: Cyndi Karoly - NC Division of Water Quality

FROM:
Steven J. Miller, PE -CLH Design, PA D ~ ~ ~ ~~~
RE: 401 EXPRESS REVIEW PERMIT
HERITAGE HIGH SCHOOL D` C ~ 2007
WAKE FOREST, NC
CC: Debbie Edwards - S&EC :~T~AWO:t .a ~.~,7 t~ . ~ v~; ~Fi~r; '
RAblCh
File (l 123-prmt)
Dear Ms. Karoly:
Attached please find two (2) hard copies of additional and revised calculations requested in your
review letter dated 29-Nov-07. Electronic copies of these calculations were transmitted to Joseph
Gyamfi on 30-Nov-07.
We offer the following responses to your comments:
I. Diffuse Flow Provisions:
a. For the 1-inch storm, please provide calculations for the design volume above permanent
pool level...
Response: Calculations for the 1-in water quality pool volume, surface area, dewatering orifice,
draw-down time and flow velocities at the pipe outlet and the end of the riprap apron
of each BMP are attached. The velocity of the discharge at the end of the riprap
. channel was determined by analyzing the riprap apron as a riprap channel with vertical
side slopes. The velocities were all calculated to be well below 2.0-fps at the end of
the riprap aprons. Below is a summary of the data requested:
Pond A
Pond A is a dry detention pond. The volume of the 1-in storm is 3,661-cf and
discharges at a maximum rate of 2.99-cfs through an 8-in orifice with a maximum
head of 3.5-ft above the floor of the pond (or 3'-2" above the centroid of the orifice).
The velocity of the discharge at the end of the pipe was calculated to be 8.9-fps and
the velocity at the end of the riprap apron was calculated to be 0.83-fps.
Pond B
Pond B is a wet detention pond. The volume of the l-in storm is 34,387-cf and
discharges at a maximum rate of 0.82-cfs through a 4-in orifice with a maximum head
of 4-ft above the permanent pool (or 3'-10" above the centroid of the orifice). The
discharge velocity at the end of the pond outlet pipe is 3.3-fps and the velocity at the
end of the riprap apron is 0.23-fps.
i i -3o-o~-i~wQ-a.a~c

30-Nov-07
Page 2
Pond C
Pond C is a wet detention pond. The volume of the 1-in storm is 13,206-cf and
discharges at a maximum rate of 0.49-cfs through a 3-in orifice with a maximum head
of 4.5-ft above the permanent pool (or 4'-4.5" above the centroid of the orifice). The
discharge velocity at the end of the pond outlet pipe is 2.9-fps and the velocity at the
end of the riprap apron is 0.27-fps.
Pond D
Pond D is a wet detention pond. The volume of the 1-in storm is 24,379-cf and
discharges at a maximum rate of 0.57-cfs through a 4-in orifice with a maximum head
of 2-ft above the permanent pool (or 1'-10" above the centroid of the orifice). The
discharge velocity at the end of the pond outlet pipe is 2.9-fps and the velocity at the
end of the riprap apron is 0.33-fps.
Pond G
Pond G is a wet detention pond. The volume of the 1-in storm is 2,372-cf and
discharges at a maximum rate of 0.03-cfs through a 1-in orifice with a maximum head
of 1-ft above the permanent pool (or 11.5" above the centroid of the orifice). The
discharge velocity at the end of the pond outlet pipe is 0.1-fps and the velocity at the
end of the riprap apron is 0.13-fps.
* Note that there are no ponds 'E' and 'F'.
2. Wet Detention Pond G:
a. Please revise flow and velocity calculations through Channels 50 and 51 with the
appropriate section slopes...
Response: The calculations for Channels 50 and 51 have been revised using channel slopes of
18.4% and 13.3°Io respectively. Non-erosive flow velocities of less than 2-fps were
calculated for both of these natural channels (1.60-fps for Channel 50 and 1.84-fps for
Channe151).
Thank you very much for your assistance in the permitting of this project. Please contact me directly if
you have any questions about these new calculations.
Sincerely,
I1-30-07-DWQ-4.duc

DESK ltii GAi.~GULATIOItiiS
GIVILISITE WORK
HERITAGE HIGH SCHOOL
WAKE FOREST, NORTH CAROLINA
DECEMBER, 2006
REV. MARCH , 2007
REV. Nov. 2007
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MacGregor Park, 125 Edinburgh South, Suite 310
Calms, North Carolina 27511
Phone: (9I9) 3I9-6716 Fax.• (919) 319- 7516

~ ~ t ~ [~; k, ;DATE
a ~ ,r ~~
.. 12-04-06
PROJECT NAME PROJECT NO ~ ~~/j
Herita a Hi h School 1123 ~ ~ ° ~
LOCATION gY ~- ~~
Wake Forest, NC K,q~
.~ ~
Drainage Area, (DA) = 7.39 ac
Impervious Area (c=0.95) = 0.71 ac
Pervious Area (c=0.35) = 6.68 ac
Cc = 0.41
Permanent Water Quality Pool
Impervious = 10
Permanent Pool Depth = 0.00 ft
SA / DA Ratio = N/A
Required Surface Area = 0 sf
Temporary Water Quality Pool
Design Storm Rainfall 1.00 in (Typically 1-in)
Runoff Coeff. (Rv = 0.05 + 0.009 (% Imperv.)) = 0.14 in/in
Required Volume (design rainfall)(Rv)(DA) = 3,661 cf
Avg. Full Depth Surface Area Provided= N/A sf
Surface Area at 1"Storage Volume= 9,600 sf
1'" Storage Volume Provided= 19,700 cf
Max. Head of Water Above Dewatering Hole = 3.50 ft
Diameter of Dewatering Hole = 8.0 in
s:\1319\0001\calcs\1123-POndSize-Pond A-void.XLS printed: 11/30/2007 2:36 PM Page 1 of 1

,. `~ ' ' ~~ ~ "
,~ ~~ a.
- ~ 1 DATE DESIGN PHASE -
,
e f ~ , ; ,.~ ~ 11 /29/07 S D / /
PROJECT NAME PROJECT NO DD / /
Herita a High School 1123 CD / X /
LOCATION BY REV / /
Wake Forest, NC KAL OTHER / /
CHECKED BY (SPECIFY)
X ~~
RIPRAP LINING -Permissible Sheer and Capacity
Outlet No: DRY POND A Drainage Area, (DA) = 7.39 ac
Sta from: Impervious Area (c=0.95) = 0.71 ac
Sta to: Pervious Area (c=0.35) = 6.68 ac
Section Length: 20 ft Cc = 0.41
Section Slope: 2.00 % One inch/hr storm= 3.01 cfs
Riprap Class: 2 (d50= 14") Temp. Storage Depth = 3.50 ft
Allowable Sheer: 4.67 Ib/sf Diameter of Dewatering Hole = 8.0 in
Allowable Depth: 1.00 ft Drawdown Rate= 2.99 cfs
CZ = c~1 ~ z~ t, -.~
Swale sizing method done by manipulation of Manning's Equation to find the depth ~- 3,,2„~ 3 /!o7-Fr
of flow that matches the known flow conditions. Performed by trial and error. ~
¢ ~ o. 3'>'9-sF
`
(_~ 3 ~~~0
INPUT DATA
Qp = 2.99 cfs flow by drawdown
n = 0.15 Class 2 Riprap Manning's Coefficient (dimensionless)
S = 0.02 ft/ft longitudinal slope (ft of fall per ft of run)
Zreq = 2.13 quantity to equate to Zav
M = 0 :1 side slope of channel (ft of run : 1 ft of rise)
NORMAL DEPTH AND VELOCITY
B D A P R Zav Remark
6 0.50 3.00 7.00 0.43 1.71 shallow
6 0.30 1.80 6.60 0.27 0.76 shallow
6 0.40 2.40 6.80 0.35 1.20 shallow
6 0.60 3.60 7.20 0.50 2.27 OK
B = bottom width of trapezoidal channel
Zav =Zreq
D = normal depth of flow
A = cross-sectional area of flow A ~xr~ _ Qn
P = wetted perimeter of the channel 1,4g ~~
R = hydraulic radius of the channel
Liss TH~~
Normal Depth, D = 0.60 ft Depth O.K.
~ 2 ~s .~~
-
.--
Velocity= 0.83 fps Velocity O.K.
SHEAR STRESS
T = yds =shear stress in Ib/sq-ft
Y = unit weight of water, 62.4 Ib/cu-ft
D = normal depth of flow in ft
S =longitudinal slope in ft/ft
shear stress, T = 0.75 Ib/sq-ft Sheer O.K.
FINAL OUTLET LINING DIMENSIONS
length, L= 20 ft
width, W = 6 ft
Permanent Channel Lining: Class 2 Riprap
(REF: Malcom, 1991) Page 1

i ~ S
`' ~`..
<, .
PROJECT NAME
Herita a Hi h School
LOCATION
Wake Forest, NC
Storm Outlet Structure
FES No.= H10
Pipe Dia= 30 in
Qio= 31.63 cfs
Qfull = 42.00 cfs
Vfull = 8.50 fps
Q1 = 4.65 cfs
From Fig. 8.06.b.1:
From Fig. 8.06.b.2:
~~ - ~~
~ __
r - --
Length
Storm Outlet Structure
FES No.= POND A
Pipe Dia= in
010 = 7.45 cfs
Qfull = 66.20 cfs
Vfull = 21.10 fps
Drawdown = 2.99 cfs
From Fig. 8.06.b.1:
From Fig. 8.06.b.2:
~~~~~ ~~
~~j ~ ~~ ~-~~ _ _i
I~ ~E~r~~tn
-- -
DATE
11-29-07
PROJECT NO
1123
BY
KAL
CHECKED BY
SJM
Q1/Qfull =
ViNfull =
Zone
0.11 Qio/Qfull =
0.67 VNfull =
Vio =
Slope=
Pipe Inv=
V1 =
D50
DMAX
Riprap Class
Apron Thickness
Apron Length
Apron Width = 3xDia
QD/Qfull =
VDNfull =
Zone
0.05 Qio/Qfull =
0.42 VNfull =
V10=
Slope=
Pipe Inv=
VDrawdown =
D50 =
DMAX =
Riprap Class =
Apron Thickness =
Apron Length =
Apron Width = 3xDia =
DESIGN PHASE
PRELIM
CONSTR
REVISION
RECORD
OTHER
(SPECIFY)
0.75
1.10
9.3 fps
5.0
215.00 ft
5.7 fps
3
10 in
15 in
1
22.5 in
20 ft
8 ft
0.11
0.67
14.2 fps
2.0
263.00 ft
8.9 fps ~'
5
14 in
21 in
2
31.5 in
20 ft
6 ft
x ii

i~' ~ ~ c .~ , 4 `_ n ~ ~ N . V ' t ~ DATE ,
1~
... ~,
' " ~ _ 12-04-06 '
PROJECT NAME PROJECT NO _, ~ // ~~ II
Heritage High School 1123 +j iJ_ ~
,_ -~ r ~
LOCATION BY ,1 ~,,
Wake Forest, NC KAL ~ '~
Drainage Area, (DA) = 16.30 ac
Impervious Area (c=0.95) = 9.62 ac
Pervious Area (c=0.35) = 6.68 ac
Cc = 0.70
Permanent Water Quality Pool
Impervious = 59
Permanent Pool Depth = 3.00 ft
SA / DA Ratio = 2.37 (from Tbl. 1.1)
Required Surface Area = 16,804 sf
Temporary Water Quality Pool
Design Storm Rainfall 1.00 in
Runoff Coeff. (Rv = 0.05 + 0.009 (% Imperv.)) = 0.58 in/in
Required Volume (design rainfall)(Rv)(DA) = 34,387 cf
Avg. Full Depth Surface Area Provided=
Surface Area at 1"Storage Volume=
1" Storage Volume Provided=
Max. Head of Water Above Dewatering Hole =
Diameter of Dewatering Hole =
Detention (Draw-Down) Time (Per NCDENR) _
Table 1.1
16,900 sf
35,209 sf
90,190 cf
4.00 ft
4.0 in
3.9 days
(Typically 1-in)
SA / DA Ratios
Permanent Pool Depth (ft)
Impervious 3.0 4.0 5.0 6.0
10 0.59 0.49 0.43 0.35
20 0.97 0.79 0.70 0.59
30 1.34 1.08 0.97 0.83
40 1.73 1.43 1.25 1.05
50 2.06 1.73 1.50 1.30
60 2.40 2.03 1.71 1.51
70 2.88 2.40 2.07 1.79
80 3.36 2.78 2.38 2.10
90 3.74 3.10 2.66 2.34

`_ i - ~ '; „~;:' ~ ~ ~,
~ DATE DESIGN PHASE
' ~~ - '
~~ z"`
. 11/29/07 SD / /
PROJECT NAME PROJECT NO DD / /
Heritage High School 1123 CD / x /
LOCATION BY REV / /
Wake Forest, NC KAL OTHER / /
CHECKED BY (SPECIFY)
X ~~jlq
RIPRAP LINING -Permissible Sheer and Capacity
Outlet No: POND B Drainage Area, (DA) = 16.30 ac
Sta from: Impervious Area (c=0.95) = 9.62 ac
Sta to: Pervious Area (c=0.35) = 6.68 ac
Section Length: 28 ft Cc = 0.70
Section Slope: 1.8 % One inch/hr storm= 11.48 cfs
Riprap Class: 1 (d50= 10") Temp. Storage Depth = 4.00 ft
Allowable Sheer: 3.33 Ib/sf Diameter of Dewatering Hole = 4.0 in
Allowable Depth: 1.00 ft Drawdown Rate= 0.82 cfs
Qcc~1.4 ZJCh
Swale sizing method done by manipulation of Manning's Equation to find the depth ~ ~ 3~ I ou = 3. s3 '
of flow that matches the known flow conditions. Performed by trial and error. fJ = p . 0 67-s~
Cd . o•foo
INPUT DATA
Qp = 0.82 cfs flow by drawdown
n = 0.409 Class 1 Riprap Manning's Coefficient (dimensionless)
S = 0.018 ft/ft longitudinal slope (ft of fall per ft of run)
Zreq = 1.68 quantity to equate to Zav
M = 0 :1 side slope of channel (ft of run : 1 ft of rise)
NORMAL DEPTH AND VELOCITY
B D A P R Zav Remark
11 0.50 5.50 12.00 0.46 3.27 deep
11 0.40 4.40 11.80 0.37 2.28 deep
11 0.20 2.20 11.40 0.19 0.73 shallow
11 0.33 3.63 11.66 0.31 1.67 OK
B = bottom width of trapezoidal channel
Zav =Zreq
D = normal depth of flow
zr~
Qn
A = cross-sectional area of flow
_
~ ~
P = wetted perimeter of the channel 1.49 CJs
R = hydraulic radius of the channel
G~sS 71Jr4~.l
Normal Depth, D = 0.33 ft Depth O.K. 2 -fps :. ok-
Velocity= 0.23 fps Velocity O.K.
SHEAR STRESS
T = yds =shear stress in Ib/sq-ft
Y = unit weight of water, 62.4 Ib/cu-ft
D = normal depth of flow in ft
S =longitudinal slope in ft/ft
shear stress, T = 0.37 Ib/sq-ft Sheer O.K.
FINAL OUTLET LINING DIMENSIONS
length, L= 28 ft
width, W = 11 ft
Permanent Channel Lining: Class 1 Riprap
(REF: Malcom, 1991) Page 3

' E ~ ~ ; G
~ ~ ~,
PROJECT NAME
Heritage High School
(LOCATION
Wake Forest, NC
f
1 k: tp ~ S
.~.i ~
Storm Outlet Structure
FES No.= POND B
Pipe Dia= in
010 = 6.04 cfs
0full = 122.00 cfs
Vfull = 12.70 fps
Drawdown = 0.82 cfs
From Fig. 8.06.b.1:
Storm Outlet Structure
FES No.= POND
Pipe Dia= 30 in
Oio= 2.36 cfs
Ofull = 44.20 cfs
Vfull = 9.00 fps
Drawdown = 0.49 cfs
From Fig. 8.06.b.1:
From Fig. 8.06.b.2:
r ~~
~~ _ ~S
~ r
~_ . ~5-
S~ t-_{r1~,-?'
DATE
11-29-07
PROJECT NO
1123
BY
KAL
CHECKED BY
SJM
OD/Ofull = 0.01 01o/Ofull =
VDNfull = 0.26 VNfull =
V10 =
Slope=
Pipe Inv=
VDrawdown =
Zone =
From Fig. 8.06.b.2: Dso = 10 in
DMAX = 15 in
_ _ ~ - Riprap Class = 1
i. Apron Thickness = 22.5 in
_ v Apron Length = 28 ft
Apron Width = 3xDia = 11 ft
_-~e~,at.h__
OD/Ofull = 0.01 Oio/Ofull =
VDNfull = 0.32 VNfull =
V10=
Slope=
Pipe Inv=
VDrawdown =
Zone =
DESIGN PHASE
PRELIM
CONSTR
REVISION
RECORD
OTHER
(SPECIFY)
0.05
0.52
6.6 fps
1.8
214.00 ft
3.3 fps ~~
3
0.05
0.52
4.7 fps
4.0
211.00 ft
2.9 fps ~----
3
D5o = 10 in
Dnnax = 15 in
Riprap Class = 1
Apron Thickness = 22.5 in
Apron Length = 20 ft
Apron Width = 3xDia = 8 ft

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PROJECT NAME PROJECT NO ll /,i~
~ ~~
~
~~
Herita a Hi h School 1123 U (r_
I~
~
LOCATION gy I1j
~~
Wake Forest, NC KAL '~
•• ~
Drainage Area, (DA) = 12.10 ac
Impervious Area (c=0.95) = 3.37 ac
Pervious Area (c=0.35) = 8.73 ac
Cc = 0.52
Permanent Water Quality Pool
Impervious = 28
Permanent Pool Depth = 3.00 ft
SA / DA Ratio = 1.26 (from Tbl. 1.1)
Required Surface Area = 6,644 sf
Temporary Water Quality Pool
Design Storm Rainfall 1.00 in (Typically 1-in)
Runoff Coeff. (Rv = 0.05 + 0.009 (% Imperv.)) = 0.30 in/in
Required Volume (design rainfall)(Rv)(DA) = 13,206 cf
Avg. Full Depth Surface Area Provided= 8,901 sf
Surface Area at 1"Storage Volume= 21,817 sf
1"Storage Volume Provided= 69,498 cf
Max. Head of Water Above Dewatering Hole = 4.50 ft
Diameter of Dewatering Hole = 3.0 in
Detention (Draw-Down) Time (Per NCDENR) = 4.5 days
Table 1.1
SA / DA Ratios
Permanent Pool Depth (ft)
Impervious 3.0 4.0 5.0 6.0
10 0.59 0.49 0.43 0.35
20 0.97 0.79 0.70 0.59
30 1.34 1.08 0.97 0.83
40 1.73 1.43 1.25 1.05
50 2.06 1.73 1.50 1.30
60 2.40 2.03 1.71 1.51
70 2.88 2.40 2.07 1.79
80 3.36 2.78 2.38 2.10
90 3.74 3.10 2.66 2.34
s:11319~00011calcs\1123-PondSize-Pond C.XLS printed: 11/302007 9:22 AM Page 1 of 1

~_ `' "` ' ~ ~,~~;,i ~~ DATE DESIGN PHASE
~ I `_I. 11/29/07 SD / /
PROJECT NAME PROJECT NO DD / /
Herita a Hi h School 1123 CD / X /
LOCATION BY REV / /
Wake Forest, NC KAL OTHER / /
CHECKED BY (SPECIFY)
~i/l
R/PRAP LINING -Permissible Sheer and Capacity
Outlet No: POND C Drainage Area, (DA) = 12.10 ac
Sta from: Impervious Area (c=0.95) = 3.37 ac
Sta to: Pervious Area (c=0.35) = 8.73 ac
Section Length: 20 ft Cc = 0.52
Section Slope: 4.0 % One inch/hr storm= 6.26 cfs
Riprap Class: 1 (d50= 10") Temp. Storage Depth = 4.50 ft
Allowable Sheer: 3.33 Ib/sf Diameter of Dewatering Hole = 3.0 in
AI-owable Depth: 1.00 ft Drawdown Rate= 0.49 cfs
'
s Equation to find the depth
Swale sizing method done by manipulation of Manning
of flow that matches the known flow conditions. Performed by trial and error.
INPUT DATA
Op = 0.49 cfs flow by drawdown
n = 0.409 Class 1 Riprap Manning's Coefficient (dimensionless)
S = 0.04 ft/ft longitudinal slope (ft of fall per ft of run)
Zreq = 0.68 quantity to equate to Zav
M = 0 :1 side slope of channel (ft of run : 1 ft of rise)
NORMAL DEPTH AND VELOCITY
B D A P R Zav Remark
8 0.50 4.00 9.00 0.44 2.33 deep
8 0.40 3.20 8.80 0.36 1.63 deep
8 0.20 1.60 8.40 0.19 0.53 shallow
8 0.23 1.84 8.46 0.22 0.67 OK
B = bottom width of trapezoidal channel _
Zatr Zreq
D = normal depth of flow
A = cross-sectional area of flow A R2r~ _ ~n
P = wetted perimeter of the channel 1.19 Vs
R = hydraulic radius of the channel .
Legs 'T61,4r~
Normal Depth, D = 0.23 ft Depth O.K. ~ Z~FPS .:
Velocit = 0.27 fps Velocity O.K.
SHEAR STRESS
T = yds =shear stress in Ib/sq-ft
Y = unit weight of water, 62.4 Ib/cu-ft
D = normal depth of flow in ft
S =longitudinal slope in ft/ft
shear stress, T = 0.57 Ib/sq-ft Sheer O.K.
FINAL OUTLET LINING DIMENSIONS
length, L= 20 ft
width, W = 8 ft
Permanent Channel Lining: Class 1 Riprap
(REF: Malcom, 1991) Page 4

f ~ ~ c DATE
,~r~.,~~'~ 11-29-07
PROJECT NAME PROJECT NO
Herita a High School 1123
LOCATION BY
Wake Forest, NC KAL
CHECKED BY
SJM
Storm Outlet Structure
FES No.= POND B
Pipe Dia= in
010 = 6.04 cfs
Ofull = 122.00 cfs
Vfull = 12.70 fps
Drawdown = 0.82 cfs
From Fig. 8.06.b.1:
OD/Ofull = 0.01 Qio/Qfull =
VDNfull = 0.26 VNfull =
V10 =
Slope=
Pipe Inv=
VDrawdown =
Zone =
DESIGN PHASE
PRELIM
CONSTR
REVISION
RECORD
OTHER
(SPECIFY)

0.05
0.52
6.6 fps
1.8
214.00 ft
3.3 fps ~-~
3
From Fig. 8.06.b.2: D5o = 10 in
DMAX = 15 in
- Riprap Class = 1
s Apron Thickness = 22.5 in
3 Apron Length = 28 ft
`---
Apron Width = 3xDia = 11 ft
- L.er~yth -_-~
Storm Outlet Structure
FES No.= POND
Pipe Dia= 30 in
Qio= 2.36 cfs
Ofull = 44.20 cfs
Vfull = 9.00 fps
Drawdown = 0.49 cfs
From Fig. 8.06.b.1:
OD/Ofull = 0.01 Qio/Qfull =
VDNfull = 0.32 VNfull =
V10 =
Slope=
Pipe Inv=
VDrawdown =
Zone =
0.05
0.52
4.7 fps
4.0
211.00 ft
2.9 fps -~----
3
From Fig. 8.06.b.2: D5o = 10 in
DM/ax = 15 in
--_ -- Riprap Class = 1
{ Apron Thickness = 22.5 in
~ ~ ~_ Apron Length = 20 ft
' "~ Apron Width = 3xDia = 8 ft
Y
__
~~„yt~,

~ , i f C y : ~ &~ ~ {` ~ ~ ~~ .t ~, T~~ ~,;,x DATE _ !i
4 . ,n, it 1k th tom.; ~ ~ ~ ~ x i t ti-
PROJECT NAME PROJECT NO l=J ~ !~
Herita a Hi h School 1123 ~ ~r ~~ ~ ri
_=~r°~~
LOCATION BY ~ `~
Wake Forest, NC KAL `' °~
Drainage Area, (DA) = 20.20 ac
Impervious Area (c=0.95) = 6.34 ac
Pervious Area (c=0.35) = 13.86 ac
Cc = 0.54
Permanent Water Quality Pool
Impervious = 31
Permanent Pool Depth = 3.00 ft
SA / DA Ratio = 1.39 (from Tbl. 1.1)
Required Surface Area = 12,266 sf
Temporary Water Quality Pool
Design Storm Rainfall 1.00 in (Typically 1-in)
Runoff Coeff. (Rv = 0.05 + 0.009 (% Imperv.)) = 0.33 in/in
Required Volume (design rainfall)(Rv)(DA) = 24,379 cf
Avg. Full Depth Surface Area Provided=
Surface Area at 1"Storage Volume=
1"Storage Volume Provided=
Max. Head of Water Above Dewatering Hole =
Diameter of Dewatering Hole =
Detention (Draw-Down) Time (Per NCDENR) _
Table 1.1
16,757 sf
37,053 sf
99,319 cf
2.00 ft
4.0 in
2.9 days
SA / DA Ratios
Permanent Pool Depth (ft)
Impervious 3.0 4.0 5.0 6.0
10 0.59 0.49 0.43 0.35
20 0.97 0.79 0.70 0.59
30 1.34 1.08 0.97 0.83
40 1.73 1.43 1.25 1.05
50 2.06 1.73 1.50 1.30
60 2.40 2.03 1.71 1.51
70 2.88 2.40 2.07 1.79
80 3.36 2.78 2.38 2.10
90 3.74 3.10 2.66 2.34
s:11319100011ca1cs11123-POndSize-Pond D-rev paac.XLS panted: 11/30!2007 9:23 AM Page 1 of 1

` ~ ~ ~ ~~~` DATE DESIGN PHASE
~'~ `> ' " 11/29/07 SD / /
PROJECT NAME PROJECT NO DD / /
Herita a High School 1123 CD / X /
LOCATION BY REV / /
Wake Forest, NC KAL OTHER / /
CHECKED BY (SPECIFY)
X ~' ~,
R/PRAP LINING -Permissible Sheer and Capacity
Outlet No: POND D Drainage Area, (DA) = 20.20 ac
Sta from: Impervious Area (c=0.95) = 6.34 ac
Sta to: Pervious Area (c=0.35) = 13.86 ac
Section Length: 24 ft Cc = 0.54
Section Slope: 8.3 % One inch/hr storm= 10.87 cfs
Riprap Class: 1 (d50= 10") Temp. Storage Depth = 2.00 ft
Allowable Sheer: 3.33 Ib/sf Diameter of Dewatering Hole = 4.0 in
Allowable Depth: 1.00 ft Drawdown Rate= 0.57 cfs

Swale sizing method done by manipulation of Manning's Equation to find the depth
of flow that matches the known flow conditions. Performed by trial and error.
INPUT DATA
Qp = 0.57 cfs flow by drawdown
n = 0.409 Class 1 Riprap Manning's Coefficient (dimensionless)
S = 0.083 ft/ft longitudinal slope (ft of fall per ft of run)
Zreq = 0.54 quantity to equate to Zav
M = 0 :1 side slope of channel (ft of run : 1 ft of rise)
NORMAL DEPTH AND VELOCITY
B D A P R Zav Remark
9 0.50 4.50 10.00 0.45 2.64 deep
9 0.40 3.60 9.80 0.37 1.85 deep
9 0.20 1.80 9.40 0.19 0.60 deep
9 0.19 1.71 9.38 0.18 0.55 OK
B = bottom width of trapezoidal channel
Zav = Zreq
D = normal depth of flow
A = cross-sectional area of flow ~ ~~~ _ 'Qn
P = wetted perimeter of the channel 1.49 ~/s
R = hydraulic radius of the channel
LASS' TK -a-,J
Normal Depth, D = 0.19 ft Depth O.K. ~ 2 FPS •'• °k'
Velocit = 0.33 fps Velocity O.K.
SHEAR STRESS
T = yds =shear stress in Ib/sq-ft
Y = unit weight of water, 62.4 Ib/cu-ft
D = normal depth of flow in ft
S =longitudinal slope in ft/ft
shear stress, T = 0.98 Ib/sq-ft Sheer O.K.
FINAL OUTLET LINING DIMENSIONS
length, L= 24 ft
width, W = 9 ft
Permanent Channel Lining: Class 1 Riprap
(REF: Malcom, 1991) Page 5

~', ~' . ~ " ' `~- ~:~~ ~ - x° -
. DATE DESIGN PHASE
~' ~ " '== `
~~ ~ 11-29-07 PRELIM / /
PROJECT NAME PROJECT NO CONSTR / /
Herita a High School 1123 REVISION / x /
LOCATION BY RECORD / /
Wake Forest, NC KAL OTHER / /
CHECKED BY (SPECIFY)
SJM
Storm Outlet Structure

FES No.= POND D Q~/Qfull = 0.01 Q1o/Qfull = 0.36
Pipe Dia= in VNfull = 0.26 VNfull = 0.91
Qio = 28.37 cfs V1o = 10.1 fps
Qfull = 78.60 cfs Slope= 8.3
Vfull = 11.10 fps Pipe Inv= 221.00 ft
Drawdown = 0.57 cfs VDrawdown = 2.9 fps ~-~
From Fig. 8.06.b.1: Zone = 3
From Fig. 8.06.b.2:
~_
I __ Length
rm Outlet Structure
FES No.= J2
Pipe Dia= 15 in
010 = 0.81 cfs
Qfull = 6.80 cfs
Vfull = 5.60 fps
Q1 = 0.11 cfs
From Fig. 8.06.b.1:
From Fig. 8.06.b.2:
ci ~~ ~I
~`~ _ ~ :;
P~'~_ 1
~E~,gth I
D5o = 10 in
Dnna,x = 15 in
Riprap Class = 1
Apron Thickness = 22.5 in
Apron Length = 24 ft
Apron Width = 3xDia = 9 ft
Q1/Qfull = 0.02 Q1o/Qfull = 0.12
V1Nfull = 0.32 VNfull = 0.67
V1o = 3.8 fps
Slope= 5.0
Pipe Inv= 215.00 ft
V1 = 1.8 fps
Zone = 2
Dso = 8 in
Dnn,ax = 12 in
Riprap Class = B
Apron Thickness = 18 in
Apron Length = 8 ft
Apron Width = 3xDia = 4 ft

.i' ;';'E ~,;;.~i~ R .. ~' ~ `~ DATE ~~
,, -
-. _ _ _.,
2OJECT NAME PROJECT NO J ~ 'J~ i~
erita a Hi h School 1123 `~,~~~ f~ ri
,_ _,
)CATION BY ~~
lake Forest, NC 1(AL ~/
'• ~
Drainage Area, (DA) = 1.91 ac
Impervious Area (c=0.95) = 0.62 ac
Pervious Area (c=0.35) = 1.29 ac
Cc = 0.54
Permanent Water Quality Pool
Impervious = 32
Permanent Pool Depth = 3.00 ft
SA / DA Ratio = 1.44 (from Tbl. 1.1)
Required Surface Area = 1,195 sf
Temporary Water Quality Pool
Design Storm Rainfall 1.00 in (Typically 1-in)
Runoff Coeff. (Rv = 0.05 + 0.009 (% Imperv.)) = 0.34 in/in
Required Volume (design rainfall)(Rv)(DA) = 2,372 cf
Avg. Full Depth Surface Area Provided=
Surface Area at 1"Storage Volume=
1" Storage Volume Provided=
Max. Head of Water Above Dewatering Hole =
Diameter of Dewatering Hole =
Detention (Draw-Down) Time (Per NCDENR) _
Table 1.1
2,289 sf
4,869 sf
2,224 cf
1.00 ft
1.0 in
4.3 days
SA / DA Ratios
Permanent Pool Depth (ft)
Impervious 3.0 4.0 5.0 6.0
10 0.59 0.49 0.43 0.35
20 0.97 0.79 0.70 0.59
30 1.34 1.08 0.97 0.83
40 1.73 1.43 1.25 1.05
50 2.06 1.73 1.50 1.30
60 2.40 2.03 1.71 1.51
70 2.88 2.40 2.07 1.79
80 3.36 2.78 2.38 2.10
90 3.74 3.10 2.66 2.34
5:\1319\0001\calcs\1123-PondSize-Pond G.XLS printed: 11/302007 9:23 AM Page 1 of 1

'~' `' `~~ DATE DESIGN PHASE
,` ,. ~` 11/29/07 SD / /
PROJECT NAME PROJECT NO DD / /
Heritage High School 1123 CD / X /
LOCATION BY REV / /
Wake Forest, NC KAL OTHER / /
CHECKED BY (SPECIFY)
X
R/PRAP LINING -Permissible Sheer and Capacity
Outlet No: POND G Drainage Area, (DA) = 1.91 ac
Sta from: Impervious Area (c=0.95) = 0.62 ac
Sta to: Pervious Area (c=0.35) = 1.29 ac
Section Length: 12 ft Cc = 0.54
Section Slope: 21.00 % One inch/hr storm= 1.04 cfs
Riprap Class: 1 (d50= 10") Temp. Storage Depth = 1.00 ft
Allowable Sheer: 3.33 Ib/sf Diameter of Dewatering Hole = 1.0 in
Allowable Depth: 1.00 ft Drawdown Rate= 0.03 cfs
~- G`i ~ a5
'
Swale sizing method done by manipulation of Manning
s Equation to find the depth
of flow that matches the known flow conditions. Pertormed by trial and error.
INPUT DATA
Op = 0.03 cfs flow by drawdown
n = 0.409 Class 1 Riprap Manning's Coefficient (dimensionless)
S = 0.21 ft/ft longitudinal slope (ft of fall per ft of run)
Zreq = 0.02 quantity to equate to Zav
M = 0 :1 side slope of channel (ft of run : 1 ft of rise)
NORMAL DEPTH AND VELOCITY
B D A P R Zav Remark
5 0.50 2.50 6.00 0.42 1.39 deep
5 0.20 1.00 5.40 0.19 0.32 deep
5 0.10 0.50 5.20 0.10 0.10 deep
5 0.04 0.20 5.08 0.04 0.02 OK
B = bottom width of trapezoidal channel
Zav = Zreq
D = normal depth of flow
A = cross-sectional area of flow A ~~~ __ ~n
P = wetted perimeter of the channel 1.d9 -~./s
R = hydraulic radius of the channel
1/~L < 2~ ~~~s
Normal Depth, D = 0.04 ft Depth O.K. 1 ~~
/y
Velocit = 0.13 fps Velocity O.K.
~ ~ ~_--~
SHEAR STRESS
T = yds =shear stress in Ib/sq-ft
Y = unit weight of water, 62.4 Ib/cu-ft
D = normal depth of flow in ft
S =longitudinal slope in ft/ft
shear stress, T = 0.52 Ib/sq-ft Sheer O.K.
FINAL OUTLET LINING DIMENSIONS
length, L= 12 ft
width, W = 5 ft
Permanent Channel Lining: Class 1 Riprap
(REF: Malcom, 1991) Page 2

'kC,~F
PROJECT NAME
Heritage High School
LOCATION
Wake Forest, NC
Storm Outlet Structure
FES No.= POND G
Pipe Dia= in
010 = 8.51 cfs
Ofull = 33.70 cfs
Vfull = 19.10 fps
Drawdown = 0.03 cfs
From Fig. 8.06.b.1:
From Fig. 8.06.b.2:
s
.~
~__
- --1
Storm Outlet Structure
FES No.= AS
Pipe Dia= 15 in
Qio= 1.33 cfs
Ofull = 19.60 cfs
Vfull = 15.90 fps
Oi = 0.18 cfs
From Fig. 8.06.b.1:
From Fig. 8.06.b.2:
T
,_
~/- `~ ~ z
. - 1 _ _.
_~e~,gt~n
QD/Ofull =
VDNfull =
Zone
DATE
11-29-07
PROJECT NO
1123
BY
KAL
CHECKED BY
SJM
0.00 Oio/Ofull =
0.00 VNfull =
V10 =
Slope=
Pipe Inv=
VDrawdown =
D50
DMAX
Riprap Class
Apron Thickness
Apron Length
Apron Width = 3xDia
01/Ofull =
ViNfull =
Zone
0.01 Qio/Ofull =
0.26 VNfull =
V10 =
Slope=
Pipe Inv=
V1 =
D50 =
DMAX =
Riprap Class =
Apron Thickness =
Apron Length =
Apron Width = 3xDia =
DESIGN PHASE
PRELIM
CONSTR
REVISION
RECORD
OTHER
(SPECIFY)
0.25
0.83
15.9 fps
21.0
261.00 ft
0.1 fps ~-"
3
10 in
15 in
1
22.5 in
12 ft
5 ft
0.07
0.52
8.3 fps
7.0
276.00 ft
4.1 fps
3
10 in
15 in
1
22.5 in
10 ft
4 ft

~ DATE DESIGN PHASE
`~~ = 11-29-07 SD / /
PROJECT NAME PROJECT NO DD / /
Herita a HS 1123 CD / x /
LOCATION BY REV / /
Wake Forest, NC bsl OTHER / /
CHECKED BY (SPECIFY)
X ~1
PERMANENT LINING -Permissible Velocity and Capacity
Channel No: CHANNEL-50 (Ex. Natural) Drainage Area: 0.75 ac
Sta from: Design Fequency: 10 yrs
Sta to: Time of Conc: 5 min
Section Length: 90 ft Intensity: 7.22 in/hr
Section Slope: 18.40 % Runoff Coeff: 0.30
Ret Class: B Discharge: 1.62 cfs
Permissible Velocity: 4.50 fps Plus Pond 'G' Q: 8.51 cfs
Allowable Depth: 2.00 ft = 10.13 cfs
Swale sizing method done by manipulation of Manning's Equation to find the depth
of flow that matches the known flow conditions. Performed by trial and error.
INPUT DATA
Qp = 10.13 cfs flow by Rational Method
n = 0.22 Grass Manning's Coefficient (dimensionless)
S = 0.184 ft/ft longitudinal slope (ft of fall per ft of run)
Zreq = 3.49 quantity to equate to Zav
M = 8 :1 side slope of channel (ft of run : 1 ft of rise)
NORMAL DEPTH AND VELOCITY
B D A P R Zav Remark
6 0.50 5.00 14.06 0.36 2.51 shallow
6 0.55 5.72 14.87 0.38 3.03 shallow
6 0.60 6.48 15.67 0.41 3.60 deep
6 0.59 6.32 15.51 0.41 3.48 OK
B = bottom width of trapezoidal channel
D = normal depth of flow Zav = 7req
A = cross-sectional area of flow ~ Rzr~ _ Qn
P = wetted perimeter of the channel 1.49 1/s
R = hydraulic radius of the channel
Normal Depth, D = 0.59 ft Depth O.K.
Velocit = 1.60 fps Vel: O.K.
SHEAR STRESS
T = yds =shear stress in Ib/sq-ft
Y = unit weight of water, 62.4 Ib/cu-ft
D = normal depth of flow in ft
S =longitudinal slope in ft/ft
shear stress, T = 6.77 Ib/sq-ft
FINAL CHANNEL LINING DIMENSIONS
B = Eft side slopes, M = 8 :1
D = 2.0 ft top width, W = 38.0 ft
Permanent Channel Lining: Grass
(REF: Malcom, 1991)

p~U
,~
~-
Page 1

~ DATE DESIGN PHASE
11-29-07 SD / /
PROJECT NAME PROJECT NO DD / /
Herita a HS 1123 CD / x /
LOCATION BY REV / /
Wake Forest, NC bsl OTHER / /
CHECKED BY (SPECIFY)
X ~1
PERMANENT LINING -Permissible Velocity and Capacity
Channel No: CHANNEL-51 (Ex Natural) Drainage Area: 2.18 ac
Sta from: Design Fequency: 10 yrs
Sta to: Time of Conc: 5 min
Section Length: 215 ft Intensity: 7.22 in/hr
Section Slope: 13.30 % Runoff Coeff: 0.30
Ret Class: B Discharge: 4.72 cfs
Permissible Velocity: 4.50 fps Plus Pond 'G' Q: 8.51 cfs
Allowable Depth: 2.00 ft = 13.23 cfs
Swale sizing method done by manipulation of Manning's Equation to find the depth
of flow that matches the known flow conditions. Performed by trial and error.
INPUT DATA
Qp = 13.23 cfs flow by Rational Method
n = 0.17 Grass Manning's Coefficient (dimensionless)
S = 0.133 ft/ft longitudinal slope (ft of fall per ft of run)
Zreq = 4.14 quantity to equate to Zav
M = 8 :1 side slope of channel (ft of run : 1 ft of rise)
NORMAL DEPTH AND VELOCITY
B D A P R Zav Remark
6 0.50 5.00 14.06 0.36 2.51 shallow
6 0.70 8.12 17.29 0.47 4.91 deep
6 0.60 6.48 15.67 0.41 3.60 shallow
6 0.644 7.18 16.38 0.44 4.14 OK
B = bottom width of trapezoidal channel
Zav =Zreq
D = normal depth of flow
A = cross-sectional area of flow ~ Rzr~ _ ~n
P = wetted perimeter of the channel 1.49 ~
R = hydraulic radius of the channel
Normal Depth, D = 0.64 ft Depth O.K.
Velocity= 1.84 fps Vel: O. K.
SHEAR STRESS
T = yds =shear stress in Ib/sq-ft
Y = unit weight of water, 62.4 Ib/cu-ft
D = normal depth of flow in ft
S =longitudinal slope in ft/ft
shear stress, T = 5.34 Ib/s -ft
FINAL CHANNEL LINING DIMENSIONS
B = Eft side slopes, M = 8 :1
D = 2.0 ft top width, W = 38.0 ft
Permanent Channel Lining: Grass
(REF: Malcom, 1991)
,~_ AIL 2fps
.. o~-
Page 1