20081866 Ver 2_Stormwater Info_20090325

CM" Kimley-Horn
and Associates, Inc.
Transmittal
Suite 300
4651 Charlotte Park Drive
Charlotte, North Carolina
28217
TEL [phone]
FAX [phone]
Ex-P OS -19 t, to v z
Date: March 24, 2009 Job Number: 018253029
Project Name: North Belgate Multi-Family Stormwater Management Plans
To: Joseph Gvamfi
Division of Water Quality
2321 Crabtree Blvd, Suite 250 lj
Raleigh, NC 27604 MAR 2 5 2009
919-715-3473 oENR-WATER QUALITY
WETLANDS AND STORMWATER BRAICIT
We are sending these by
? U.S. Mail ® FedEx Hand Deliver
? Other:
We are sending you
Z Attached
Shop Drawings
Other:
Copies Date
n Under separate cover via
the following items:
® Prints/Plans ? Samples ? Specifications ? Change Orders
No. Description
3 03/19/09 1 North Belgate Multi-Family Stormwater Management Plans
2 03/19/09 2 North Belgate Multi-Family Stormwater Management Calculations
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 Ej Resubmit r-1 Copies for approval
As requested Approved as noted Submit ? Copies for distribution
For review and comment ? Returned for corrections Return R 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:
Signed Beverly Rosenbloom, E.I.
Page 1
Permit Number: X? 0$ - I O V b Yz
(to be provided by DWQ)
Drainage Area Number:
Wet Detention Basin Operation and Maintenance Agreement
I will keep a maintenance record on this BMP. This maintenance record will be kept in a
log in a known set location. Any deficient BMP elements noted in the inspection will be
corrected, repaired or replaced immediately. These deficiencies can affect the integrity
of structures, safety of the public, and the removal efficiency of the BMP.
The wet detention basin system is defined as the wet detention basin,
pretreatment including forebays and the vegetated filter if one is provide
/`O 4`4:> -yj
Gj 4J
This system (check one):
? does ® does not incorporate a vegetated filter at the outlet. ,19
ilea
This system (check one): ?T4ai#os1?R.w 10 L,
qN0 q?
? does ® does not incorporate pretreatment other than a forebay."V fry
Rg
Important maintenance procedures: ?
- Immediately after the wet detention basin is established, the plants on the
vegetated shelf and perimeter of the basin should be watered twice weekly if
needed, until the plants become established (commonly six weeks).
- No portion of the wet detention pond should be fertilized after the first initial
fertilization that is required to establish the plants on the vegetated shelf.
- Stable groundcover should be maintained in the drainage area to reduce the
sediment load to the wet detention basin.
- If the basin must be drained for an emergency or to perform maintenance, the
flushing of sediment through the emergency drain should be minimized to the
maximum extent practical.
- Once a year, a dam safety expert should inspect the embankment.
After the wet detention pond is established, it should be inspected once a month and
within 24 hours after every storm event greater than 1.0 inches (or 1.5 inches if in a
Coastal County). Records of operation and maintenance should be kept in a known set
location and must be available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potential problem: How I will remediate the problem:
The entire BMP Trash/ debris is resent. Remove the trash/ debris.
The perimeter of the wet Areas of bare soil and/or Regrade the soil if necessary to
detention basin erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Vegetation is too short or too Maintain vegetation at a height of
long. a roximatel six inches.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 1 of 4
(I . * I I
?. i t. 0 R I - a ?
Permit Number:
(to be provided by DWQ)
Drainage Area Number:
BMP element: Potential problem: How I will remediate the problem:
The inlet device: pipe or The pipe is clogged. Unclog the pipe. Dispose of the
Swale sediment off-site.
The pipe is cracked or Replace the pipe.
otherwise damaged.
Erosion is occurring in the Regrade the swale if necessary to
swale. smooth it over and provide erosion
control devices such as reinforced
turf matting or riprap to avoid
future problems with erosion.
The forebay Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design depth for possible. Remove the sediment and
sediment storage. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Erosion has occurred. Provide additional erosion
protection such as reinforced turf
matting or riprap if needed to
prevent future erosion problems.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than spraying.
The vegetated shelf Best professional practices Prune according to best professional
show that pruning is needed practices
to maintain optimal plant
health.
Plants are dead, diseased or Determine the source of the
dying. problem: soils, hydrology, disease,
etc. Remedy the problem and
replace plants. Provide a one-time
fertilizer application to establish the
ground cover if a soil test indicates
it is necessary.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than spraying.
The main treatment area Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design sediment possible. Remove the sediment and
storage depth. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Algal growth covers over Consult a professional to remove
50% of the area. and control the algal growth.
Cattails, phragmites or other Remove the plants by wiping them
invasive plants cover 50% of with pesticide (do not spray).
the basin surface.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 2 of 4
Permit Number:
(to be provided by DWQ)
Drainage Area Number:
BMP element: Potential problem: How I will remediate the problem:
The embankment Shrubs have started to grow Remove shrubs immediately.
on the embankment.
Evidence of muskrat or Use traps to remove muskrats and
beaver activity is present. consult a professional to remove
beavers.
A tree has started to grow on Consult a dam safety specialist to
the embankment. remove the tree.
An annual inspection by an Make all needed repairs.
appropriate professional
shows that the embankment
needs repair. if applicable)
The outlet device Clogging has occurred. Clean out the outlet device. Dispose
of the sediment off-site.
The outlet device is damaged Repair or replace the outlet device.
The receiving water Erosion or other signs of Contact the local NC Division of
damage have occurred at the Water Quality Regional Office, or
outlet. the 401 Oversight Unit at 919-733-
1786.
The measuring device used to determine the sediment elevation shall be such
that it will give an accurate depth reading and not readily penetrate into
accumulated sediments.
When the permanent pool depth reads 6 feet in the main pond, the sediment
shall be removed.
When the permanent pool depth reads 6 feet in the forebay, the sediment shall
be removed.
BASIN DIAGRAM
ill in the blanks)
Sediment Removal
Bottom
Permanent Pool Elevation 674
669 Pe anen?
------------------Volume
668 -ft Min.
Sediment
Storage
FOREBAY
Pool
- - -Sediment Removal Elevation 668 ............ Volume
\ ------ Sediment
Bottom Elevation
MAIN POND
1-ft
Storage
Form SW401-Wet Detention Basin O&M-Rev.4 Page 3 of 4
Permit Number:
(to be provided by DWQ)
I acknowledge and agree by my signature below that I am responsible for the
performance of the maintenance procedures listed above. I agree to notify DWQ of any
problems with the system or prior to any changes to the system or responsible party.
Project name:North Belgate Multi-Family
BMP drainage area number
Print name:Crescent Resources, LLC - David Niekamp
Title:Director of Retail Development
Address:400 South Tryon Street, Suite 1300, Charlotte NC 28285
Phone: [phone]L.
Signature:
Date: / bl1 (# !-
-r
Note: The legally responsible party should not be a homeowners association unless more than 50% of
the lots have been sold and a resident of the subdivision has been named the president.
a Notary Public for the State of
N C , County of do hereby certify that
10AYiQ i ' personally appeared before me this
day of C .Zd?1 , and acknowledge the due execution of the
forgoing wet detention basin maintenance requirements. Witness my hand and official
seal,
SEAL
My commission expires
filly Commission Expires August 17, 2013
Form SW401-Wet Detention Basin O&M-Rev.4 Page 4 of 4
syCq B-t$?LP
BELGATE MULTI-FAMILY DEVELOPMENT
CHARLOTTE, NORTH CAROLINA
?? In
RA R 2 5 2009
YNET(AIyDSAND STpR) WWAW7EW)
NANCY
REVISED STORMWATER MANAGEMENT CALCULATIONS
Prepared for:
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
C A R
'FESS16. ??
0
co
D ?
March 2009
KRA Ref: 018253029
,., ,
s .,
?. ,t.
Kimley-Horn
and land 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 1
Drainage Area (DA) = 9.42 Acres
Impervious Area (IA) = 6.28 Acres
Percent Impervious (1) = 66.7 %
Required Surface Area
Permanent Pool Depth:
SA/DA =
Min Req'd Surface Area =
Required Storage Volume:
Design Storm =
Determine Rv Value =
Storage Volume Required =
Elevations
3.25
3.85
15798
1
0.05+.0
22,226
ft
_ (90% TSS Removal via Pond)
sf (at Permanent Pool)
inch (Project Does Not Drain to SA waters)
D9 (1) = 0.65 in/in
_ cf (above Permanent Pool)
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
16,386 sf
26,063 cf
31
101
31
Is Permanent Pool Surface Area Sufficient (yes/no)?
Volume of Storage Provided 26,063 cf
Total Volume Sufficient (yes/no)? Yes
Area (s.f.)
20,847
16,386
(Elevation = 671.40)
(Elevation = 670.00)
Yes ( 16386 > 15798 ) sf
Orifice Size = 2.50 inches
Drawdown Time = 2.80 days
WET DETENTION BASIN
Project Information
Project Name: Belgate Multifamily
KHA Project #: 018253029
Designed by: TDR
Revised by: BRR
Revised by:
Site Information
Date:
Date:
Date:
10/20/2008
1/19/2009
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
U2 Days - U. "I 5U0 CTS
Q5 Days = 0.0603 cfs
Orifice Size = 2.50 in
Q Office = 0.108 cfs
Drawdown Time = 2.80 days
less than 5 days (yes/no) ? Yes
greater than 2 days (yes/no) ? Yes
(I-iowraie requlrea Tor a z aay arawaown)
(Flowrate required for a 5 day drawdown)
(Diameter)
Orifice Equation: Q=CAgd(2gh) 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
WET DETENTION BASIN
Project Information
Project Name: Belgate Multifamily
KHA Project #: 018253029
Designed by: TDR
Revised by: BRR
Revised by:
Site Information
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 = 0.3077 cfs
Qs Days = 0.1231 cfs
Orifice Size = 2.50 in
Q office = 0.140 cfs
Drawdown Time = 2.1 days
less than 5 days (yes/no) ? Yes
greater than 2 days (yes/no) ? Yes
10/21/2008
1/19/2009
(Flowrate required for a 2 day drawdown)
(Flowrate required for a 5 day drawdown)
(Diameter)
Orifice Equation: Q=CAgV(2gh) Q2 < Q < Q5
c = 0.6
A9= Area of Pipe = r</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
= w
d?
Y m
C
u
N
G
m
3
h V
OJ >
ns
F16- 3
m H
d >
Q u
? C
u a
? LD
? W
3 E
? W
C G
10 ry
N Y
E U
3 O
o co
> G
O
Y
O
E
G Co
Q LL N
O
3 Lo
2 N
N
'o O
°
a?
m
ON NO
O O
O)Ir-
m
2 22
0 0 0
IIof
co co
C
O
N 4i ?
E E n >
L ? a
o z •o y v v
= c ar v
u LL` O0 ?n ?n
a
v
m > >
? 2 p aj Qj
.O LL Y
IL`
0)
V ?
ra u
ti rn ?
a ti
rn
C f6 ?
0)
M Q o
c v ;
o °D
" G o
G •? LL
O)
OI 0

E rn rn .1 o0 0 o
00 n
N a)
00
U 7 0 0 N r -A
O w
N o
N m
00
lD
n
0
Q
> r m ?i o0 of ? rn ?

ar
rn o o rn m a o0
3 V o O l
_
O .J C
a-4 n
14 N
N 00
N to
N o0
ei O
N
M
> O
H
u

..
f 6 LMD v v U) W m ° m °n'
r-I N m IT 0 n 00 00 Q1
m 0 0 0 0 0 0 0 0 0
W N 0 0 0 0 0 0 0 0 0
Q
J
?0 .•-. Lo N 00 N Ln n n a

Q Q" n e-I e-I N N m co m C
m
W
C

O O O O T T O
O
c O
o a
O.
_
` ?
y
u c
E
o
cu
a
0
0
m
00
0
N
ci
m
m n
W Iq
? -t
4 to
?q Ln
v
E a
a, ? o
E o H
O >
p d
O
> V)
M c T
ro m
v E m
`o (V `o
LL a LL
a, O
m n 1o Ln n oo
m
C,4
m .4
00 ri
M
N a
r,
ID VI ON

O
0
0 ? N m n n n V

N O N

O O1 n

' `^

N
> O lD V 00 a 1 6 o -i m 00 Lr ,..?
•I 1 N M m a to 0
U0 e
00 0 r14 Ul
Lj
U r . M Ln
Q

3
N
k
-4
n
?
N
`
° M
m 0) n N
u O O L
D ID o
L 0
0 O O
1 l
D O
O n -4-4 o
c W r,, r
.... V Ln lD n m v In to CO 00 lC-4
i ?4
N -:T
N LD
LD
F
u
t0
tV
O
N
O
N
0
O
V
O
O
m
O
Ln
r4
C'
n In
m n
c ci
V Lo
D - N
O N
N
m
m LD
to
co
N C
N D
OD n M
O n
a

O n

m
rp O O 4
N i
' ri N N N N M V ? V1 Li u
1 lD
v 0 0 0 0 0 0 0 o O O O O o 0 0 O
Q
W

m Ol m Ll1 n rn 00 In 07
J m w m o C m rn N O M N
C) N ?r
co Q
a N to
, In
r
O t0
N

M
.--1

a
ci

m

o
N

n
M

00
ao

Ol
o
N
a

0

O
)
co
M
r
Ln
l
n
I ?--? .--i N N N N N N

a o ' -4 N m a ui
. . . ? 'o Ci
N to O lD O LD lD 'D m tDD tDD co lDD Loo wo

= 6 6
c
V) a a) a c

Q
-
O r
c t
Ln ` o
m

u
E v
c
O
O
W ° E E o
o o
?-
?-
co 0)
a ar
F-
d'
m
N
ti n I to M
00
ti m
E
? v
a a
> Ln o
c c a,
a ar ?
G c N
ro fa
E E 5
. v
a a co
N
C
°
M
3
u
io
N U
w a
m
3
N 'C.
M N
Q u
? C
u ?
R m
.? y
E
H W
C C
<s N
W Y
E u
7 O
[L
O
6
c
Q
9

?a
Y m
pp-

T
E
IL N
O
Cl)
7 u?
g N
N W
?p O
O
N
co
r_
O
QIQ
NI NI N
m co m
p p p
mix
Q! of
m m
R N U
E E u s
o z -o y a v
Q 'N > >
d 0 Y
O
a`
N
d
u N
f6 u
e-i m CO
C c-I
CT
C_ 6 Ln
i) N
O] Q
c a 3
O
? O
C •? LL
N
d 0
0
v
c
0

3
a L
O O
co
N

?
w
>
Z 3
a

O w
O cc E
0) N 3
E
? O
N
`o C

Y
U N

w h
t Y
V Z, O
O N CO O W
co (D O O V (O LO LO 0 O
V M 7 N P' c l!
n tfi M CO
.1C II II II II II II aj II II II 11
p c C y v .n a N C C C
Q (0 f6 m C> N= C
J CL cl
6 ` N N _N N 0 Q Q
3 7 'a. p p U O
c _ Q m o,
Q m d
'
o m (n ° 3
? o ° 0 0 0,
N O ? ? m N
tq U U 3 'd ?
? 7 N
C7
N
C
3 ?
U Ill
CA
. 2
O
m y
T N
m E
Q N
N N
N
E 0 3
m _E
c
'? C C
E E
O
O
O O O U) (O
(O CO O M O
N I? ?
O
T II II II II 11 II
3 w N v v w?
U O T L C U
cc 0
fn C7 t 3 c O
T n a J > N
C C'1 m T W d
Of > 3 N LL
`m O _
E C1
tco
W p T
o p 3
C N Cl
'N NN N
fA >
S y
m'¢
Y m
C
11
u
N
C
O
M
16
3
10
u
d >
R
3
N G
f6 yl
? T
Q C
u ar
w ?
? N
3 E
H W
C C
10 L0
01 y
u
? O
O m
O
M
O T
E
C M
Q L- N
- O
7 O
N
N O
L0 O
o>
0)
m
rn
00
0
I 0
N N'N"
M
0) 0) O
ca cc cc
0 0 0
a. a.
2 d'
mlm
C
O
E E ???sT
`OZ vv
v
> >
v .p Q v a) ai
r
m x p Of LY
.O d Y
a
v
U ?
f6 U
N r I\
OL e
O
C N ?
N ?
m Q
C t
O to
0 O
C •? LL
OJ ?•
v o
0

O 01 N n N
u m O O N
lD r
LD t` C', a ? ? ?
Q --I Y) lp 01 N
j i f e-I r1
O m m Ln Ln N t` 00

_O
O
O
O
O
0 -1
O 1
n U)
a0 0
C

O
-1
N
N
m
14
rl l
N
rd
7 O
H
v
c
o 0
N 0)
N Cl
.-t Ol
ei c-I
M m
Ln 00
.•-? t`
00 tl-
Ln
N M V Ln LD n 00 -
,? 0 0 0 0 0 0 0 0 0
W 0 0 0 0 0 0 0 0 0
Q
J
-4 a -tt N 00 N Ln N O
w O m N N n N N 00 r--I
Q 1-i ?1 ri N N m m m
m
W

O ?

tio 00 01 O ''1 N M m ^ •,
n LD LD LD t.0 lD LD 1 11 d
{
O
C O
p
. a
Q
- c
v
Lj C
?a
E
o
0)
CL
0
O
N
N
n 00
-1 LD
Q
E n
v 3 O
E p Ln
_3 > N
> v `n
T C T
f6 ? f9
a E w
O v O
LL a LL
w .?
E L11 W T
- O N r` u1 ~ 0 0 `•'1 .?-I
0 0 0 m a IT cn 0) n Lr o rn N 0000

L j
N-I
N0 o
m -I
1* r?
v
Ln "
O C;
t` 06
0) 'D
0O 'D Ln
Ln 00
0000 c
Q
a
rn

00
Lo
ID
7 U O O to 000 q LLr
0, O 0?1 M
T m
O
O
00
N
.... Lr LD 00 0) lD lD O0 0o a) 0) N
N N M
O
H
f0 'i O 00 lD M o, M M Ln 0, 00 O c-1 N O1 M

Ol LD
N N
V r-1
n N
O 7
M 0,
ED rl
co O
L.n 00
e-1 n
Ln n
O N
N 00
to N
-- •I 00
-
m O c•1 ri e-1 N N N N M V Ul LD LD LD I,. n
x 0 0 0 0 0 0 0 0 O O O 0 0 0 0 O
Q
W

f0 00 N ?-I L!1 .? ~ N d' r <D lD r1 O Ol
G) Ln r14 r4 r4
O ?o 0
Q N m 0 lD n 00 O N N Ln 00 V 00 m
N N e-I N .--1 N N N N M M

2

p00 n
lp 00
O Q1
O O
n ri
n N
r M
n
M r
N
C Ln
n LD
h M
O n
L? 00
n 0)
t\
Z Lp Lo ID t"
C

C 6
O
w 0
O

Y
p L
C a v a c

p
O C
C
v1
L ` a
m

U
E v
C
m
O ?
p
O
0 O E CL
O CL
E a
O
o
m a H
O
Ln
m
e-1
t` rn M
m N
co --1
Ol
a,
E 11
3 01
o a
> Ln 2
p p D
v d -D
C C N
? R
E E E
.N
OJ OJ O
a a m
9
d<
Y m
C
u
0
Y
a7
u
m
H v
ar >
a
as H
a T
Q u
al C
V ?
a5 OD
L N
E
N W
c c
of la
d y
E u
o
m
> c
O
Y
2
wO >,
c m rn
Q LL N
= O
M
ui
? N
a) W
fa O
01
N
m
a
O
ON)
O W N ml ml a?
m m m
IY fY
fY 0
m m
ja a, XL
E E u n
ca y ? ? ?
O Z •? y -a a
C v O
CL to ?
.
O 2 C K
d Y
O
a`
N
a1
m u
N n n
Ol 'y
c; •1
N
C o Ln
m a U
c ?' 3
o °D
c m u'
a)
Ql 0

0
m
3
IT
N r

co m

al ?
c6

>

E w
O

O a1
E

m N 3

o E
?
y
° 'c
-

U U
-ca
n
r Y
v ..- O
O O N u) O O
W vJ O V O u) ui O
C M C,4 7 ry r N
co ui 6 CD
Y 11 II II 11 II II N II 11 II II
O c c N v N C C
m L L f6 'O a Y .L... w v O
= a) N N U O U> O) O_l L
O c Q f0 o 0 C> N N U
la -J O N O Q J Q
O j 3 'Q-. ?? U O
Q` i N m Q o)
U O
O t
O) O 2 O O O)
N O N
U U 0
(n 01
3 'd
> > N
3
O'
N
C_
r L
N Q.
3 ?
U Cl)
t ?
? O
C
C
3
Q N
N N
N
m
E °
m E
E E
O
N O ? (fl
r r O O
(O r
T 11 II II 11 II II
3 w v x
U T
L C O
EL N
f CY 3 c p
(jD -Q
C C'J ? >, L1J N
El >
N
a) Q - N
E L U
W a) >
o p co
3
C N
1N (6
N
Permit No.
(to be provided by DWQ)
W A TF9O
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 111) must be printed, filled out and submitted along with all of the required information.
I. PROJECT INFORMATION
Project name Belgate Mufti-Family
Contact person Beverly Rosenbloom
Phone number 704-319-7699
Date 3/19/2009
Drainage area number 1
iL DESIGN INFORMATION -- T ?i
Site Characteristics
Drainage area 410,335 ft
Impervious area, post-development 273,557 ft2
% impervious 66.67 %
Design rainfall depth 1.0 in
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 stone 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 Off 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
Form SW401-Wet Detention Basin-Rev.6-2120/09
22,227 ft3 OK
26,063 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 fmsl
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
Parts I. & II. Design Summary, Page 1 of 2
Permit No.
(to be provided by DWQ)
Ill. DESIGN INFORMATION
Surface Areas
Area, temporary pool 68,235 f?
Area REQUIRED, permanent pool 15,798 f?
SA/DA ratio 3.85 (unitless)
Area PROVIDED, permanent pool, Apex,_p?d 16,066 f 2 OK
Area, bottom of 1 Oft vegetated shelf, Abo, Sha, 10,261 ff
Area, sediment cleanout, top elevation (bottom of pond), Abo,-d 4,138 ff
Volumes
Volume, temporary pool 26,063 ft3 OK
Volume, permanent pool, Vaef -. 56,117 ft3
Volume, forebay (sum of forebays if more than one forebay) 11,689 ft3
Forebay % of permanent pool volume 20.8% % OK
SAIDA Table Data
Design TSS removal 90 %
Coastal SAIDA Table Used? N (Y or N)
Mountain/Piedmont SA/DA 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, Vim,,,-Pc 56,117 ft3 OK
Area provided, permanent pool, Ate -,, , 16,066 ft2 OK
Average depth calculated 3.49 ft OK
Average depth used in SAIDA, day, (Round to nearest 0.5ft) 3.5 It OK
Calculation option 2 used? (See Figure 10-2b) N (Y or N)
Area provided, permanent pool, Ate„„-,,d fe
Area, bottom of 1 Oft vegetated shelf, Abo, a,?j, ftz
Area, sediment cleanout, top elevation (bottom of pond), Ab,_pw
"Depth" (distance b/w bottom of 10ft shelf and top of sediment)
Average depth calculated
Average depth used in SAIDA, da,, (Round to nearest 0.5ft)
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 (Cw)
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
ftz
ft
ft
it
Y (Y or N)
2.50 in
in2
0.60 (unitless)
0.43 ft
N (Y or N)
(unitless)
(unifless)
ft
It
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 No.
(to be provided by DWQ)
OF WA TF9
A`MiA O? 7G 71
NCDENR t
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 Ill) must be printed, filled out and submitted along with all of the required information.
?1. PROJECT' INFORMATION
Project name Belgate Multi-Family
Contact person Beverly Rosenbloom
Phone number 704319-7699
Date 3119/2009
Drainage area number 2
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 lyr 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
477,853 e
346,738 ft2
72.56 %
1.0 in
27,997 ft3 OK
53,163 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
4.93 ft3/sec
32.80 ft3/sec
27.87 ft3/sec
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
Y (Y or N)
676.3 fmsl OK
Form SW401-Wet Detention Basin-Rev.6-2/20/09 Parts I. & 11. Design Summary, Page 1 of 2
Permit
(to be provided by DWO)
11. DESJGN INFORMATION
Surface Areas
Area, temporary pool 27,100 ft3
Area REQUIRED, permanent pool 18,875 ft2
SAIDA ratio 3.95 (unitless)
Area PROVIDED, permanent pool, Apen-pod 19,129 ftz OK
Area, bottom of 10ft vegetated shelf, AW -shelf 12,514 ftZ
Area, sediment cleanout, top elevation (bottom of pond), Ab t,.d 5,052 ft'
Volumes
Volume, temporary pool
Volume, permanent pool, Vp,-y,
Volume, forebay (sum of forebays if more than one forebay)
Forebay % of permanent pool volume
SAIDA Table Data
Design TSS removal
Coastal SAIDA Table Used?
Mountain/Piedmont SAIDA Table Used?
SAIDA ratio
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b)
Volume, permanent pool, V L--"
Area provided, permanent pool, Ap, -P,,
Average depth calculated
Average depth used in SAIDA, d, (Round to nearest 0.5ft)
Calculation option 2 used? (See Figure 10-2b)
Area provided, permanent pool, APL,,,-PDC9
Area, bottom of 1 Oft vegetated shelf, AbDr 5wf
Area, sediment cleanout, top elevation (bottom of pond), Abt,.d
"Depth" (distance b/w bottom of 10ft shelf and top of sediment)
Average depth calculated
Average depth used in SAIDA, d.„ (Round to nearest 0.5ft)
Drawdown Calculations
Drawdown through orifice?
Diameter of orifice (if circular)
Area of orifice (if-non-circular)
Coefficient of discharge (Cc)
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
53,163 ft3 OK
66,897 ft3
12,760 ft3
19.1% % OK
90 %
N (Y or N)
Y (Y or N)
3.95 (unitless)
Y (Y or N)
66,897 ft3 OK
19,979 ft2 Insufficient. Data does not equal data previously entered.
3.35 ft OK
3.5 ft OK
N (Y or N)
ft
ftz
ft2
Y (Y or N)
2.50 in
in2
0.60 (unifless)
0.73 ft
N (Y or N)
(unitless)
(unitless)
It
ft
4.93 ft3/sec OK
0.92 ft3/sec OK
0.10 ft3/sec
2.90 days OK, draws down in 2-5 days.
Drawdown time varyinq from expected value by more than a half day.
3 :1 OK
10 :1 OK
10.0 ft OK
3 :1 OK
2.4 :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.6-2120/09 Parts I. & II. Design Summary, Page 2 of 2