20081866 Ver 2_More Info Received_20090320 (2)

Ex;p o8- IS6Ie Vz
? M ? Kimley-Horn
and Associates, Inc.
Suite 300
4651 Charlotte Park Drive
Charlotte, North Carolina
28217
TEL [phone]
FAX [phone]
Transmittal
Date: March 19, 2009 Job Number: 018253029
Project Name: North Belgate Multi-Family Stormwater Management Plans
To: Joseph Gvamfi
Division of Water Quality
r,'r?
2321 Crabtree Blvd, Suite 250
Raleigh, NC 27604 MAR o P 2,000 ?
919-715-3473
DENR - YlER OtALIP?
-
WETLA1a0S MID S T ORIA,`TER BRF,NDl
We are sending these by
0 U.S. Mail ® FedEx Hand Deliver
? Other:
We are sending you
® Attached
? Shop Drawings
R Other:
Copies Date No. Description
2 03/19/09 1 North Belgate Multi-Family Stormwater Management Plans
2 03/19/09 2 North Belgate Multi-Family Stormwater Management Calculations
fl 3 03/19/09 3 Financial Responsibility Form for Pond 2 (Forthcoming, see below)

These are transmitted as checked below:
® For your use Approved as submitted Resubmit 0 Copies for approval
As requested Approved as noted E] Submit E] Copies for distribution
For review and comment E] Returned for corrections ? Return ? Corrected prints
Joe,
We raised the bottom elevation in the forebay of Pond 2. The client is re-signing the
financial responsibility forms and sending them to you separately. Otherwise, you should
have all the information you need. Please give me a call if you have any questions.
Thanks!
Copy to:
Under separate cover via the following items:
® Prints/Plans ? Samples ? Specifications ? Change Orders
Signed Beverly Rosenbloom, E.I.
Page 1
I
?.x.p D 8 - t8 ?? v2
BELGATE MULTI-FAMILY DEVELOPMENT
CHARLOTTE, NORTH CAROLINA
REVISED STORMWATER MANAGEMENT CALCULATIONS
v.°
MAR 200.9
Prepared for: DENR - WATER QUALITY
WETLANDS AND STORMA.WATER BRANCH
Crescent Resources, LLC
400 S. Tryon Street, Suite 1300
Charlotte, North Carolina 28202
Prepared by:
Kimley-Horn and Associates, Inc.
4651 Charlotte Park Drive, Suite 300
Charlotte, North Carolina 28217
CAR
'S?o?oFESS/p -
i9? ?NG [ N ???' 03?
P?
(.9.04
March 2009
KHA Ref: 018253029
t it
C..n Kimley-Horn
and Associates, Inc.
WET DETENTION BASIN
Project Information
Project Name:
KHA Project #:
Designed by:
Revised by:
Revised by:
Belgate Multifamily
018253029
TDR Date: 10/16/2008
BRR Date: 1/19/2009
Date:
Site Information
Sub Area Location: Drainage Area 1
Drainage Area (DA) = 9.42 Acres
Impervious Area (IA) = 6.28 Acres
Percent Impervious (1) = 66.7 %
Required Surface Area
Permanent Pool Depth: 3.25 ft
SA/DA = 3.85 (90% TSS Removal via Pond)
Min Req'd Surface Area = 15798 sf (at Permanent Pool)
Required Storage Volume:
Design Storm = 1 inch (Project Does Not Drain to SA waters)
Determine Rv Value = 0.05 + .009 (1) = 0.65 in/in
Storage Volume Required = 22,226 cf (above Permanent Pool)
Elevations
Bank Elevation = 675.00 ft
Top of Pond Elevation = 675.00 ft
Temporary Pool Elevation = 671.40 ft
Forebay Weir = 670.00 ft
Shelf Beginning Elevation = 670.50 ft
Permanent Pool Elevation = 670.00 ft
Shelf Ending Elevation = 669.50 ft
Bottom Elevation = 663.00 ft
Wet Basin Areas/Volumes
Area @ Top of Temporary Pool =
Area @ Top of Permanent Pool =
Volume of Temporary Storage =
Side Slopes of Pond =
Side Slopes of Shelf =
Side Slopes of Pond (below shelf) =
20,847 sf
16,066 sf
25,839 cf
31
101
31
Is Permanent Pool Surface Area Sufficient (yes/no)?
Volume of Storage Provided 25,839 cf
Total Volume Sufficient (yes/no)? Yes
Area (s.f.)
20,847
16,066
(Elevation = 671.40)
(Elevation = 670.00)
Yes ( 16066 > 15798 ) sf
Orifice Size = 2.50 inches
Drawdown Time = 2.77 days
I
WET DETENTION BASIN
Project Information
Project Name: Belgate Multifamily
KHA Project #: 018253029
Designed by: TDR
Revised by: BRR
Revised by:
Site Information
10/20/2008
1/19/2009
Date:
Date:
Date:
Sub Area Location: Drainage Area 1
Drainage Area (DA) = 9.4 Acres
Impervious Area (IA) = 6.3 Acres
Percent Impervious (1) = 66.7 % (Drainage Area)
Orifice Sizing
Q2 Days = 0.1495 cfs
Q5 Days -
Orifice Size =
Q office =
Drawdown Time =
0.0598 cfs
2.50 in
0.108 cfs
2.77 days
less than 5 days (yes/no) ?
greater than 2 days (yes/no) ?
Yes
Yes
Orifice Equation: Q=cAgV(2gh)
(Flowrate required for a 2 day drawdown)
(Flowrate required for a 5 day drawdown)
(Diameter)
Q2< Q< Q5
c = 0.6
A9= Area of Pipe = n/4D2
g = gravity = 32.2 ft/s2
h = orifice head = 1/3 (TPE-PPE-1/2D)
TPE = Temporary Pool Elevation
PPE = Permanent Pool Elevation
D = Diameter
T I
Kimley-Hom
pP-Z?
11111- and Associates, Inc.
WET DETENTION BASIN
Project Information
Project Name: Belgate Multifamily
KHA Project #: 018253029
Designed by: TDR Date: 10/16/2008
Revised by: BRR Date: 1/19/2009
Revised by: Date:
Site Information
Sub Area Location: Drainage Area 2
Drainage Area (DA) = 10.97 Acres
Impervious Area (IA) = 7.96 Acres
Percent Impervious (1) = 72.6 %
Required Surface Area
Permanent Pool Depth: 3.25 ft
SA/DA = 3.95 (90% TSS Removal via Pond)
Min Req'd Surface Area = 18875 sf (at Permanent Pool)
Required Storage Volume:
Design Storm = 1 inch (Project Does Not Drain to SA waters)
Determine Rv Value = 0.05 +.009 (1) = 0.70 in/in
Storage Volume Required = 27996 cf (above Permanent Pool)
Elevations Area (s.f.)
Bank Elevation = 679.00 ft
Top of Pond Elevation = 679.00 ft
Temporary Pool Elevation = 676.30 ft 27,100
Forebay Weir = 674.00 ft
Shelf Beginning Elevation = 674.50 ft
Permanent Pool Elevation = 674.00 ft 19,979
Shelf Ending Elevation = 673.50 ft
Bottom Elevation = 667.00 ft
Wet Basin Areas/Volumes
Area @ Top of Temporary Pool = 27100 sf (Elevation = 676.30 )
Area @ Top of Permanent Pool = 19979 sf (Elevation = 674.00 )
Volume of Temporary Storage = 54141 cf
Side Slopes of Pond = 3 : 1
Side Slopes of Shelf = 10 : 1
Side Slopes of Pond (below shelf) = 3 : 1
Is Permanent Pool Surface Area Sufficient (yes/no)? Yes ( 19979 > 18875) sf
Volume of Storage Provided 54141 cf
Total Volume Sufficient (yes/no)? Yes
Orifice Size = 2.50 inches
Drawdown Time = 2.1 days

WET DETENTION BASIN
Project Information
Project Name: Belgate Multifamily
KHA Project #: 018253029
Designed by: TDR
Revised by: BRR
Revised by:
Site Information
10/21/2008
1/19/2009
Date:
Date:
Date:
Sub Area Location: Drainage Area 2
Drainage Area (DA) = 11.0 Acres
Impervious Area (IA) = 8.0 Acres
Percent Impervious (1) = 72.6 % (Drainage Area)
Orifice Sizing
Q2 Days = 0.3133 cfs
Q5 Days -
Orifice Size =
Q Office =
Drawdown Time =
0.1253 cfs
2.50 in
0.140 cfs
2.1 days
less than 5 days (yes/no) ?
greater than 2 days (yes/no) ?
Yes
Yes
Orifice Equation: Q=cAgV(2gh)
(Flowrate required for a 2 day drawdown)
(Flowrate required for a 5 day drawdown)
(Diameter)
Q2< Q< Q5
c = 0.6
Ay= Area of Pipe = rd4D2
g = gravity = 32.2 ft/s2
h = orifice head = 1/3 (TPE-PPE-1/2D)
TPE = Temporary Pool Elevation
PPE = Permanent Pool Elevation
D = Diameter
N
C
O
u
N
N V
a >
M
11= 3
H 'O.
ns ?
u w
R
i d
3 E
H W
C O
? 07
OJ y
E O
3
O m
> O
A
O
C
Q
E
m¢
E?
Y ?m
C
t'
T
E
o rn
LL N
O
7 V)
? N
0) W
1]
O)
N
CD
O O
C) 0
O O
O n
?Iml
N N 0)
cc co M
0 00
0] I D]
,_
O
E E u a n'
o Z o v v O
c v v
w a oo ^
.+ o Q
0) 2 p C OC
•? d Y
a
0)
u '^
t0 U
1 O) tD
7 ci
0)
co Q
c 0010 ;
? C LL
01 ?
0

E o en ci M
to a)
oo U) r
?
V O
O
O n
O n
V) co
V)
'•i

lx? M M M
Q
O
.4
N
t
n
00 6 N
.-I
>
OJ
^
E
O
n
O
O
00
N
M
LD
O V O O O V) O V) V) tD O)

rl
i1
N
N
e-1
e1
14 6
> O
F
u N o ei M M M M 0) M
O
N
0 N
0 N
0 M
0 N
0 'D
0 n
0 00
O O)
O
W v 0 0 0 6 6 6 6 0 0
j

O
M 00
in
Q lD r, N
.-4 N
N 00
N N
M Vl
M N

M
W
W
?D to t m m n
N u u ?D ? lD
O
O
C
o a
Q C
V
a ?p
E
O ?
a
9
O
C
Q)
00
N
m
Ln M
co ci
M m
o v
ci V1
I?
d
E a
v 2 o
E o in
> w
o "O
> !n
> c
v E v
`o d `O
LL D. LL
C O
E
M n lD u) n 00 co .-I 1-4 V) cT
n N m O ?

O
O
O
O R
N M
Ot V)
n lD
n M
n N
C OJ
N 8
O M
N
O 01
M
' n V) V1
> ? I ce
LO _Z
00 O N V)
L,
U 'i N M co V In D ,
Q
(E"
N
O
0)
V) 0)
M
00 O) n N
D
J w
V tD
Vi tD
? 00
n O
o O)
V tD
V) oO'
D m 0o i
lD

O O m O m
V) M
ID
N O
N O
co M
en O
n V1 N
n
IT
n V)
M n
1-1 tt )D
O M N M co -?T ID n O ?T M M
Ip O O 'I N 'i e-1 N N N M tt t7 V) V) V) lD
w 0 o o o 0 o 0 0 O O O O O O O O
Q

M
M
^

N

o0

n

oO

O)

V) .-I

O at

0) M

e-i V)

N n

V
0)
V
co
N
V)

ID
oO

Ll
O E
E M
N to
ci 0
ci V
N
D M
N
n O)
M
W N
tD
Ol N
O C
N O)
7 ,
0 co
O O)
?-1 00
M n
u) n
n
Q M V V) t N N N N N

Z
0
a
pOp
M
"
a
'
N
1-0
O
n
O
C
O)
M
r
O 4
n r4
n
M
n
It
n
n
l
D l
D
DD
'
?
l
D
?
w
lD
m
n
O
n
ID
m
m
lD
tD
Q n m Lo

-6

O
?- 7
0
0

y
C
O t
ut d a LL r_

O

O -C

N
l
N
m
v
a)
C
O
O

a 6
E
O
E Q
O
D o
a
F
co
ci
M
lD
O
N
E
O
c
a,
c
E
v
a
Q
0
a
c
ra
E
a
a
m
II
01
Q
0
ar
v
h
'a
m
N
1=
O
m
uu
co
y u
d >
m
3
N •Q
M N
T >
c
u d
m
? v
3
W
"O a
C C
m m
aC, Y
C U
7 O
O to
O
O
c
Q
E.x
m<
2.
C
T
E
m rn
IL N
O
Cl)
7 to
CN
N
? O
0)
O
CO
C
O
O O
00
O O
?I[hl
UI N N
co 0 0
=I
CO D]
ja 0)
E E a
v a
o z
c v a a
c v a
M y N
U y > '>
y° x p W CC
•? a x
a
N
d
u '^
m V
r-I 01 lD
Ol
C m N
N d
IT1 Q v
c " 3
o °D
M O
C a u-
GJ ?
y O
0

O

7
N L
rn

N
co N

>
7
U
N
E 1
w N
O
O
d1
N

Y
U
N
_
O
O
w
7

'C

n
m
L
? Y
U O
co co O O 00 V ( LO ? D
V co N V N P' C V N
co Lo to (D
Y II II II II II II N 11 11 II 11
U C f? N G
_o '_ '_ v v (n v v
m L L f6 a a Y w L v
C .? N N N U J?'D O] O) L
m E m C > J = C
N) N N EL 0 Q Q
O 7 7 E?? cLJ O
Q 2 m m
F
o 65 >
o ° o 0 0>
N p V E of
y U o a
>
Q
CD
c
r L
N Q
3 •D
U
rn
0
m N
(D
c
m m
3 ?
O. N
N N
N
:1 0
E a 7
(0 E
C
E E
O
O O O LO O
(fl O c, I-
(0
T 11 11 II 11 II II
3 w N ? ? ? ?
a N m cm m
3 3
N C7 c m°

u ° '2 J N
N
N
O (n T
C
a? W
> 3 m n
d o= a)
E L U U
W p T
3
o p
c
• to
W m
M
I L
N
C
D
ld
u
u
10
v
a, >
N
'a
M y)
L u
Q V
V ?
10 ?
01
E
LA W
c c
R f6
d y
E u
>o
N
O
C
Q
2
aTi Q
E'er
Y m
C
u
E
LL N
O
7 LO
CN
N
? O
_rn
a1
m
r_
O
0 O
O O
O O
N `
?IMI
0 o 0
of Of
mlm
N Jt
j6 n
E E ? °
o z o m-ov
? C N N
d 00 .
>.C
d a Y p s m
O
a`
d
v ?
m u
N I? t\
01 L..j
O e-1
C R ?
•? v
Q
co
c " 3
o °D
m o
+J c -
C •- LL
d ?
v p
0

o n ? .-1 0 0 0
o o rn
M v
M n
Ql LD
M m L`?D O L?D
Q
o 1-1 m Ln of y

a
E
m
m
N
001
O
m
000
7 u O O cn 01 LO M O N
O" a-i ti N M N N N f6
>

t6 M In Ol O Ln N cT N Ln
.... ? N m N W C)
ro 0 0 0 L
n
0 ID
0 0 m
0 ? ?
W v 0 0 0 0 0 0 0 0 0
? Q

O N m OM V LOD W 0m1 7 -4 O

"'
^ N LO N m h N 1, N
Ln
Q N c-1 N N M v C
m

W
cr-
m m rn o N m m
LD LD n n ^ n L
V) LD to LD O LD
O
c o
D
O
2
_ C
Lu
u c

v E
p ?
o_
9
O
O
O
N
1-
m
O ?
LD I?
co ri
r 1 LD
Q
E a
N 7 O
E O V)
7 > y
o a
> N
m R
a,a, E tea,
O v O
LL D_ LL
N
7
^
Vl
lb
D1
O
N
n
1n
-1
e-I
01
'•?
Ln
r-
r-I
N Ln

0
0
0 co
v r4
D V
r+ m rn M 1

' L.n
, ?
n N

O O

LD 01

Ln N

00 co
> N O r r" M m C V) 00
Lj H N M V V Ln LD I, M
Q
I? W M .-'I N lA m m m ti ON a 0
3 j) 0 0 LMD W .?-q Ln o rn m lD m o N W N
O ` Ln LD m T -04 to lD l%1 N LI) 00 .a)
4 m
N
m
f4

ra N
_q O
w W
r4 l0
r1 M
N a)
V M
0) m
n Ln
O O1
00 W
n O
(? .-1
N N
00 m
N m
co
dl .y V I? O M lD W Ln N Ln O N Ln .-L lp
m N N N M 7 Ln lD LD LD 1- n
v o O O O O O o O O 0 0 0 0 0 0 O
Q
W
(p lb N a-I Ln c-I •-i N V 1? l0 LO a-I O L--I N
-7 01
LD
J ^
o N
N n
a m
N m
f` .-+
Ln LD
N a
N m
N V o
1--4 rl
LO t
o [T
O
Q
m m
Ln
lD
N
w OD 0 ,--1 N Ln
-I 00
l V
N lD
N n
N co
N r-1
M M
M
H L--1 N c r

Z
°a
i
h
N
Ql
o
c-1
N
M
V
?
0
W
01
p
p
m ?D LO ?o r, rl r, r, r,
^ ^
^ ^
O LD LD - O LD O n
Lfl lD
p lD lD
lD to lp to

C L O
a
v O
a y
c
o n Ln m
M o ra
u E C O O` O
E O O
p m d F w F
D_ F-
at
M
ci
I? ? dl M
r- I D1
n m
" '•I
E
>
`c
a
c
rt
E
`a
a
Q
c
a
c
ra
E
v
LL
N
a
0
v
LA
c
ca
m
N
C
O
i+
m
u
U
m
N V
d m
N 'a
m H
Q U
u ?
m ?
3
H W
= C
m Cp
N y
E U
30
om
>o
m
0

dQ
E9
2'.
pp-

a
m am
1.L N
O
M
7 U-1
N
? O
N
m
??O
I I
?IC',
co m co
000
?m
of ? QM-1
0
•m bi it
E E -o
a
o z o a o v
C ? C ? h
u a` oo ?
Q N N
N 2 O K
•Q n. Y
a
N
`u
m u
N I? t`
Ol 'y
o
C m ?
N ?
m ¢ ?
c
o to
m O
LL
d ?
d 0
0

C
O

N L
O)
N U7
>>
N N

6

E

? N

Ol E

N
y
U U

?
A
? Y
?2 O
O O N (D O
co cD o v cD
v M cc) t if V V (M CD
.Y 11 II II 11 II II dj 11 II II II
o c v N U G C
to r L m -a v .Y ? w? v
C 0) U N N N U 0 'O 01 O_) L
O C U U O U> N N U
y m Q m m m c J= C
Ip J N O N N O Q Q
? j w d' ? ? U O
c o Q o
Q 2 m co 0
r m :? 3:
0
o ° 0 0 0>
O L .U
N 0 ?j E rn
co U o .?
> > N
0-
aD
c
r L
c?i n
3 °
U
01
w t0
C N
? C
m °1
3 •.E-0
N N
a)
E a :3
m E
E E
O
n t` O ? r 0
0
o
r ?
T 11 II II II 11 II
m N N «" .Y'' ? ?

CL N Co Of O m
3
N C7 O
m
>+ j
_
° O. J N N
Cn
C

D T w
M
y ?`
3
C
m O = m
E r w 0
w

0 n
m
0 3

co
N
N m
N
Permit
NCDENR
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part III) must be printed, filled out and submitted along with all of the required information.
(to be provided by DWQ)
O?OF W ATF9OG
O T
I. PROJECT INFORMATION
Belgate Multi-Family
Project name
Contact person Beverly Rosenbloom
Phone number 704-319-7699
Date 311912009
Drainage area number 1
II. DESIGN` INFORMATION
Site Characteristics
Drainage area
Impervious area, post-development
% impervious
Design rainfall depth
Storage Volume: Non-SA Waters
Minimum volume required
Volume provided
Storage Volume: SA Waters
1.5" runoff volume
Pre-development 1-yr, 24-hr runoff
Post-development 1-yr, 24-hr runoff
Minimum volume required
Volume provided
Peak Flow Calculations
Is the pre/post control of the 1 yr 24hr storm peak flow required?
1-yr, 24-hr rainfall depth
Rational C, pre-development
Rational C, post-development
Rainfall intensity: 1-yr, 24-hr storm
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Pre/Post 1-yr, 24-hr peak flow control
Elevations
Temporary pool elevation
Permanent pool elevation
SHWT elevation (approx. at the perm. pool elevation)
Top of 1 Oft vegetated shelf elevation
Bottom of 1 Oft vegetated shelf elevation
Sediment cleanout, top elevation (bottom of pond)
Sediment cleanout, bottom elevation
Sediment storage provided
Is there additional volume stored above the state-required temp. pool?
Elevation of the top of the additional volume
410,335 fe
273,557 ft
66.67 %
1.0 in
22,227 ft3 OK
25,839 ft3
OK, volume provided is equal to or in excess of volume required.
ft3
ft3
ft3
0 ft3
ft3
Y (Y or N)
2.6 in
0.15 (unitless)
0.70 (unitless)
0.12 in/hr OK
4.71 ft3/sec
27.03 ft3/sec
22.32 ft3/sec
671.40 fmsl
670.00 fmsl
fmsl
670.50 tmsl
669.50 fmsl Data not needed for calculation option #1, but OK if provided.
664.00 fmsl
663.00 fmsl Data not needed for calculation option #1, but OK if provided.
1.00 ft
Y (Y or N)
671.4 fmsl OK
Form SW401-Wet Detention Basin-Rev.6-2120/09 Parts I. & II. Design Summary, Page t of 2
Permit
(to be provided by DWQ)
IC DESIGN INFORMATION - -
Surface Areas
Area, temporary pool 68,235 ft
Area REQUIRED, permanent pool 15,798 ft
SAIDA ratio 3.85 (unitless)
Area PROVIDED, permanent pool, A,,,,,,_,,d 16,066 ft3 OK
Area, bottom of 1 Oft vegetated shelf, Ab?t_a,,t 10,261 ffz
Area, sediment cleanout, top elevation (bottom of pond), Abotp„d 4,138 ft?
Volumes
Volume, temporary pool 25,839 ft3 OK
Volume, permanent pool, Vra, l 54,813 ft3
Volume, forebay (sum of forebays if more than one forebay) 10,385 ft3
Forebay % of permanent pool volume 18.9% % OK
SAIDA Table Data
Design TSS removal 90 %
Coastal SAIDA Table Used? N (Y or N)
Mountain/Piedmont SAIDA Table Used? Y (Y or N)
SAIDA ratio 3.85 (unitless)
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b) Y (Y or N)
Volume, permanent pool, Vv,-.ro 54,813 ft3 OK
Area provided, permanent pool, A,._pd 16,066 ftz OK
Average depth calculated 3.41 ft OK
Average depth used in SAIDA, da,,, (Round to nearest 0.5ft) 3.5 ft OK
Calculation option 2 used? (See Figure 10-2b) N (Y or N)
Area provided, permanent pool, Ap._pw ftz
Area, bottom of 1 Oft vegetated shelf, Abt_sw ft?
Area, sediment cleanout, top elevation (bottom of pond), Aboty.d ftz
"Depth" (distance b/w bottom of 1Oft shelf and top of sediment) ft
Average depth calculated ft
Average depth used in SAIDA, d., (Round to nearest 0.5ft) ft
Drawdown Calculations
Drawdown through orifice?
Diameter of orifice (if circular)
Area of orifice (if-non-circular)
Coefficient of discharge (CD)
Driving head (Ho)
Drawdown through weir?
Weir type
Coefficient of discharge (C.)
Length of weir (L)
Driving head (H)
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Storage volume discharge rate (through discharge orifice or weir)
Storage volume drawdown time
Additional Information
Vegetated side slopes
Vegetated shelf slope
Vegetated shelf width
Length of flowpath to width ratio
Length to width ratio
Trash rack for overflow & orifice?
Freeboard provided
Vegetated filter provided?
Recorded drainage easement provided?
Capures all runoff at ultimate build-out?
Drain mechanism for maintenance or emergencies
Y (Y or N)
2.50 in
in2
0.60 (unitless)
0.43 ft
N (Y or N)
(unitless)
(unitless)
ft
ft
4.71 ft3/sec OK
0.79 ft3/sec OK
0.11 ft3/sec
2.80 days OK, draws down in 2-5 days.
OK, drawdown time is correct.
3 :1 OK
10 :1 OK
10.0 ft OK
3 :1 OK
2.3 :1 OK
Y (Y or N) OK
1.1 ft OK
N (Y or N) OK
Y (Y or N) OK
Y (Y or N) OK
Gravity Pipe
Form SW401-Wet Detention Basin-Rev.6-2/20/09 Parts I. & II. Design Summary, Page 2 of 2
Permit
ATIMPA
NcDENR
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part III) must be printed, filled out and submitted along with all of the required information.
(to be provided by DWQ)
W A TF9OG
J ti
O Y

t.' PROJECT INFORMATION
Project name Belgate MultWamily
Contact person Beverly Rosenbloom
Phone number 704-319-7699
Date 311912009
Drainage area number 2
II. DESIGN INFORMATION ?
Site Characteristics
Drainage area 477,853 ffz
Impervious area, post-development 346,738 ffa
% impervious 72.56 %
Design rainfall depth 1.0 in
Storage Volume: Non-SA Waters
Minimum volume required 27,997 ft3 OK
Volume provided 54,141 ft3
OK, volume provided is equal to or in excess of volume required.
Storage Volume: SA Waters
1.5" runoff volume
Pre-development 1-yr, 24-hr runoff
Post-development 1-yr, 24-hr runoff
Minimum volume required
Volume provided
Peak Flow Calculations
Is the prelpost control of the 1yr 24hrstorm peak flow required?
1-yr, 24-hr rainfall depth
Rational C, pre-development
Rational C, post-development
Rainfall intensity: 1-yr, 24-hr storm
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Pre/Post 1-yr, 24-hr peak flow control
Elevations
Temporary pool elevation
Permanent pool elevation
SHWf elevation (approx. at the perm. pool elevation)
Top of 1 Oft vegetated shelf elevation
Bottom of 1 Oft vegetated shelf elevation
Sediment cleanout, top elevation (bottom of pond)
Sediment cleanout, bottom elevation
Sediment storage provided
ft3
ft3
ft3
0 ft3
ft3
Y (Y or N)
2.6 in
0.15 (unitless)
0.70 (unitless)
0.12 in/hr OK
4.93 ft3lsec
32.80 ft3lsec
27.87 ft3lsec
676.30 fmsl
674.00 fmsl
fmsl
674.50 fmsl
673.50 fmsl Data not needed for calculation option #1, but OK if provided.
668.00 fmsl
667.00 fmsl Data not needed for calculation option #1, but OK if provided.
1.00 ft
Is there additional volume stored above the state-required temp. pool? Y (Y or N)
Elevation of the top of the additional volume 676.3 fmsl OK
Form SW401-Wet Detention Basin-Rev.6-2/20/09
Parts I. & It, Design Summary, Page 1 of 2
Permit No.
(to be provided by DWQ)
it. DESIGN INFORMATION - - -
Surface Areas
Area, temporary pool 27,100 ftz
Area REQUIRED, permanent pool 18,875 ft
SAIDA ratio 3.95 (unitless)
Area PROVIDED, permanent pool, Ap,.-pcd 19,979 ft3 OK
Area, bottom of 1 Oft vegetated shelf, Ab. sheff 12,514 W
Area, sediment cleanout, top elevation (bottom of pond), AW-, d 5,052 ftz
Volumes
Volume, temporary pool 54,141 ft3 OK
Volume, permanent pool, Vpe--" 67,747 ft3
Volume, forebay (sum of forebays if more than one forebay) 13,610 ft3
Forebay % of permanent pool volume 20.1% % OK
SAIDA Table Data
Design TSS removal 90 %
Coastal SAIDA Table Used? N (Y or N)
Mountain/Piedmont SAIDA Table Used? Y (Y or N)
SAIDA ratio 3.95 (unitless)
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b) Y (Y or N)
Volume, permanent pool, Vp--P d 67,747 ft3 OK
Area provided, permanent pool, Ap,--" 19,979 ftz OK
Average depth calculated 3.39 ft OK
Average depth used in SAIDA, day, (Round to nearest 0.5ft) 3.5 ft OK
Calculation option 2 used? (See Figure 10-2b) N (Y or N)
Area provided, permanent pool, Ate,, j fe
Area, bottom of 10ft vegetated shelf, A ,hw ft3
Area, sediment cleanout, top elevation (bottom of pond), Awl.d ftZ
"Depth" (distance b/w bottom of 1Oft shelf and top of sediment) ft
Average depth calculated It
Average depth used in SAIDA, d.„ (Round to nearest 0.5ft) ft
Drawdown Calculations
Drawdown through orifice? Y (Y or N)
Diameter of orifice (if circular) 2.50 in
Area of orifice (if-non-circular) in2
Coefficient of discharge (Co) 0.60 (unitless)
Driving head (Hp) 0.73 It
Drawdown through weir? N (Y or N)
Weir type (unitless)
Coefficient of discharge (Cw) (unitless)
Length of weir (L) It
Driving head (H) It
Pre-development 1-yr, 24-hr peak flow 4.93 ft3/sec OK
Post-development 1-yr, 24-hr peak flow 0.92 ft3lsec OK
Storage volume discharge rate (through discharge orifice or weir) 0.10 ft3lsec
Storage volume drawdown time 2.90 days OK, draws down in 2-5 days.
Drawdown time varvinq from expected value by more than a half dav.
Additional Information
Vegetated side slopes 3 :1 OK
Vegetated shelf slope 10 :1 OK
Vegetated shelf width 10.0 ft OK
Length of flowpath to width ratio 3 :1 OK
Length to width ratio 2.4 :1 OK
Trash rack for overflow & orifice? Y (Y or N) OK
Freeboard provided 1.1 It OK
Vegetated filter provided? N (Y or N) OK
Recorded drainage easement provided? Y (Y or N) OK
Capures all runoff at ultimate build-out? Y (Y or N) OK
Drain mechanism for maintenance or emergencies Gravity Pipe
Forth SW401-Wet Detention Basin-Rev.6-2 /2 010 9 Parts I. & It. Design Summary, Page 2 of 2
9S 10S 13S
Pre-dev DA-2 Post-d v DA-2 Post-dev 2 Undetained
11 12
Multi-Family Wet Pond 2 Outfall 2
Subca Reach on Link Drainage Diagram for Mulit-Family North Pond 2
Prepared by Kimley-Horn and Associates, Inc., Printed 3/19/2009
HydroCAD® 8.50 s/n 005123 © 2007 HydroCAD Software Solutions LLC

Mulit-Family North Pond 2 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 3/19/2009
HydroCAM 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 2
Summary for Subcatchment 9S: Pre-dev DA-2
Runoff = 4.93 cfs @ 12.18 hrs, Volume= 0.486 af, Depth= 0.49"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Area (ac) CN Description
11.800 70 PRE - Woods/Meadow - Good condition HSG C
11.800 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
21.4 Direct Entry, From spreadsheet
v
3
0
X
Subcatchment 9S: Pre-dev DA-2
Hydrograph
--------------
4.93 cfs --------------------------- i-------; ----- - - ------- ------- ------ --------------- ------ ------
5
Charlotte; 24-hr
1 1- r 'r -124 h r
4 Rainfall=2.68'
Rulltioff Ar6aT11.800 air
. -----
Riunoff VQlulme=0.486 of
RUndff !DOth'0.49:
:---- T ----------------------- :------- ---- , - r -. r
z ' Tc=21.4 M: in
QW7D
¦ Runoff
0
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
Mulit-Family North Pond 2 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 3/19/2009
HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 3
Summary for Subcatchment 10S: Post-dev DA-2
Runoff = 32.80 cfs @ 11.96 hrs, Volume= 1.539 af, Depth= 1.68"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Area (ac) CN Description
10.970 91 POST - Pond Drainage Area
10.970 Pervious Area
Tc Length Slope Velocity Capacity Description
_(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry, From spreadsheet
Subcatchment 10S: Post-dev DA-2
Hydrograph
¦ Runoff
v
3
0
U.
Time (hours)
1 .
Mulit-Family North Pond 2 Charlotte 24-hr 1-yr 1 yr- 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 3/19/2009
HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 4
Summary for Subcatchment 13S: Post-dev 2 - Undetained
Runoff = 1.31 cfs @ 11.97 hrs, Volume= 0.062 af, Depth= 0.65"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Area (ac) CN Description
1.140 74 POST - Undetained Drainage Area
1.140 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 13S: Post-dev 2 - Undetained
Hydrograph
¦ Runoff
v
3
0
U.
., ., ?., ?., ? .. .... .... .... ... ... ..- Time (hours) - - -
Mulit-Family North Pond 2 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 3/19/2009
HydroCAM 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 5
Sumi
Inflow Area = 10.970 ac,
Inflow = 32.80 cfs @
Outflow = 0.28 cfs @
Primary = 0.28 cfs @
Secondary = 0.00 cfs @
mary for Pond 11 P: Multi-Family Wet Pond 2
0.00% Impervious, Inflow Depth = 1.68" for 1 yr - 24 hr event
11.96 hrs, Volume= 1.539 of
24.00 hrs, Volume= 1.442 af, Atten= 99%, Lag= 722.8 min
24.00 hrs, Volume= 1.442 of
0.00 hrs, Volume= 0.000 of
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Peak Elev= 676.31'@24.00 hrs Surf.Area= 27,138 sf Storage= 56,125 cf
Plug-Flow detention time= 2,467.7 min calculated for 1.442 of (94% of inflow)
Center-of-Mass det. time= 2,432.6 min ( 3,239.3 - 806.8 )
Volume Invert Avail.Storage Storage Description
#1 674.00' 137,143 cf Custom Stage Data (Prismatic) Listed below
Elevation Surf.Area Inc.Store Cum.Store
_(feet) (sq-ft) (cubic-feet) (cubic-feet)
674.00 19,979 0 0
675.00 24,296 22,138 22,138
676.00 26,441 25,369 47,506
677.00 28,671 27,556 75,062
678.00 31,011 29,841 104,903
679.00 33,469 32,240 137,143
Device Routing Invert Outlet Devices
#1 Primary 667.00' 24.0" x 90.0' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 666.00' S=0.0111'/' Cc= 0.900 n=0.013
#2 Device 1 674.00' 2.5" Vert. Orifice/Grate C= 0.600
#3 Device 1 676.30' 3.50' W x 0.50'H Vert. Orifice/Grate C=0.600
#4 Device 1 677.00' 3.50' W x 0.17'H Vert. Orifice/Grate C=0.600
#5 Secondary 677.50' 15.0' long x 5.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00 3.50 4.00 4.50 5.00 5.50
Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65
2.67 2.66 2.68 2.70 2.74 2.79 2.88
#6 Device 1 677.50' 4.00' x 3.00' Horiz. Orifice/Grate Limited to weir flow C=0.600
Primary OutFlow Max=0.26 cfs @ 24.00 hrs HW=676.31' (Free Discharge)
L1=Culvert (Passes 0.26 cfs of 43.61 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.24 cfs @ 7.16 fps)
3=Orifice/Grate (Orifice Controls 0.02 cfs @ 0.36 fps)
-Orifice/Grate ( Controls 0.00 cfs)
-Orifice/Grate (Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=674.00' (Free Discharge)
t5=Broad-Crested Rectangular Weir (Controls 0.00 cfs)

Mulit-Family North Pond 2 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 3/19/2009
HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 6
Pond 11 P: Multi-Family Wet Pond 2
Hydrograph
I ¦ Inflow
? Outflow
¦ Primary
¦ Secondary
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
A r+
Mulit-Family North Pond 2 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 3/19/2009
HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 7
Summary for Pond 12P: Outfall 2
Inflow Area = 12.110 ac, 0.00% Impervious, Inflow Depth > 1.49" for 1 yr - 24 hr event
Inflow = 1.49 cfs @ 11.97 hrs, Volume= 1.504 of
Primary = 1.49 cfs @ 11.97 hrs, Volume= 1.504 af, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Pond 12P: Ouffall 2
Hydrograph
S
1.49 cfs IofidwAte&121.110 aC
------- --- ------- ------
-------------- ------- ------- ------- ------- ------- -------
1
0
a
0
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
¦ Inflow
¦ Primary