SW8990802_COMPLIANCE_20030313

STORMWATER DIVISION CODING SHEET
POST -CONSTRUCTION PERMITS
PERMIT NO.
SW D
DOC TYPE
❑ CURRENT PERMIT
❑ ' APPROVED PLANS
❑ HISTORICAL FILE
COMPLIANCE EVALUATION INSPECTION
DOC DATE���
YYYYMM DD

u
August 22, 2002
Stormwater Narrative
Leland Food Lion
Leland, NC
'1TE 99063
Leland Food Lion is an existing commercial subdivision treated by wet detention. An
existing building totaling 39,000 sf and 11,700 of future building expansion have been
included in the existing permit along with 7,350 sf of sidewalk and 145,640 sf of asphalt
parking. We are proposing to add 15,949 sf of additional asphalt area to the existing plan.
This drainage area contains two out parcels allocated 87,391 sf of impervious area to be
treated within the pond. The total impervious area to be treated by the pond is 305,820 sf.
This creates 50.9% impervious. Out flow will be routed to an unnamed tributary of
Sturgeon Creek, classified C-SW.
RECEIVED
MAR 13 2g03
DWQ
PROJ# �GU�C/%jdUZ

8r22r2002
CDC
LELAND FOOD LION
Stormwater Calculations
99063
Drainage Area
s . ft. I acres
ra osed development 1 601,128 1 13.80
Total 1 601,128 113.80.
% impervious = 0.509
= 50.9%
Use 51.0%
Stormwater Calculations:
Time of Concentration
Hydraulic Length (L) = 323 ft.
change in Height (H) = 1.75 ft.
To = (Ls IH)'J" / 128
4.98 min.
Flow for 10 year, 6 hour Storm (Q1o):
QPRE _ (CPRE) x (1t0) x (Area)
21.74 cfs
QPosT = (CPOST) x (110) x (Area)
= 53.03 cfs
Soil Storage Caoacitv for 10 vear Storm:
CN = (Si)(% imp.) + (49)(1-% imp.)
66
Pa 4.80 in. for 10 yr, 6 hr storm
S = 10001CN - 10
= 5,15
Depth (D)= [P-(0.2)(S)]` I [P+(0.8)(S)]
1.59 in.
Time to Peak Flow:
TP = [(43.5)(D)(Area)] 101
18.03 min.
Detention Pond Design:
Pond Size:
Elevation
ft.
Surface Area
(sq. ft.
Normal Pool
34.50
33,258
State Flood Pool
35.50
35.861
City Flood Pool
36.50
38,463
Top of Bank
1 40.00
1 48,264
Bottom of Pool
1 28.50
1 19,371
Total Provided City Storage VOIUme:
Vol. _ ((Normal pool SA + Flood Pool SA) 1 21
x (F.P. elev. - N,P, elev.)
71,721 cu. ft.
City Storage Required for 10 year Storm
TP = Vol. I (1.39)(0P)
Vol. = (TP)(1.39)(QP)(60 sec.)
QP = QIO,POST - Q10,PRE
31.30 cfs
Vol, - 47.065 cu. ft.
OverallPONDmod
Impervious Area
Land Use
s ,ft.
acres
Building area
49,500
1.14
Asphalt area
161,589
3.71
Concrete area
7,350
0.17
2 Outparcels 85%
87,381
2.01
Total
305,820
7.02
CPRE = 0.25
CPosT' ("6 imp.)(.95)+(1-% imp.)(.25)
0.61
110 = 6.30 inlhr
150 = 7.79 in/hr
Flow for 50 year, 6 hour Storm (Q50):
QPRE _ (CPRE) x (150) x (Area)
26.88 cfs
QPoST = (CPOST) x (Iso) x (Area)
= 65.58 cfs
oen arora a i,a acn for z)u year worm:
CN = (81)(% imp,) + (49)(1-% imp.)
66
P = 6.42 in, for 50 yr, 6 hr storm
S= 1000ICN-10
5.15
Depth (D)= [P-(0.2)(S)[21 [P+(0.8)(S)]
2.76 in,
Time to Peak Row:
TP = ](43.5)(D)(Area)] 1 050,POST
= 25.23 min.
State Surface Area Reauirement at normal pool:
1:9
Pond side slopes = 3 :1
Depth below N.P. = 6 ft.
SAlDA = 0.0277
(Chart for 90% TSS Removal for Wet Detention
Pond without Ve etat"ve Filter
Required SA = (SAIDA) x (Total Drainage Area)
= 16.651 s . ft.
State Volume Requirement for Storage of first 1" of runoff:
Vol. = [(1112) x (DA) x (% imp.)] +
[(1112) x (DA) x (1-% imp,) x C]
C = 0.2
30,407 cu. ft.
Provided Stora a Volume for State Requirement:
State Vol, = 34,560 cu, ft,
City Storage Required for 50 year Storm:
TP = Vol. 1 (1.39)(0P)
Vol. = (TP)(1.39)(0P)(60 sec.)
QP " Q50,PosT - 050,PRE
��11111111 ] 1l1//� r = 38.70 cfs
�, CAR �� Vot. = 81,423 cu. ft.
SEAL 9
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8/22/2002
CDC
Fofebay7
Required Volume
Vol. = 20% of pond storage volume
= 31,577 cu.ft.
Outlet Structure Design:
Flow for 2-day drawdown:
for 1st 1" of stormwater,
Q = Required State Vol. 1172,800 sec. (2-days)
= 0,176 cfs
Required Area of Pipe for 2-day drawdown;
A= Q 1 [Cd x SQRT(2 x g x h)]
Cd = 0.6
9 = 32.2 ft.Is2
h = (F.P. elev.- N.P. elov.) 12
0.5 ft.
A= 0.0517sq. ft.
Diameter of Piae for 2-day drawdown
DIA. = SQRT[(A x 4) 1 pi]
= 0,2565 ft.
= 3.08 in.
' USE 2.5" ORIFICE
Outlet Structure Check:
Using a 4' x 4' Basin,
Perimeter L = 16 ft.
LELAND FOOD LION
Stormwater Calculations
Q = CIA
C = (% imp.)(.95) + (1-% imp.)(.25)
0.61
1 = 6.30 in. for a 10 yr. Storm
A = 13.80 Acres
= 53.03 cfs
Q= CwxLxH"5
H = [Q 1 (Cw x L)]2"
Cw = 3
— 1.07 ft.
Peak elevation = flood pool elevation + H
= 37.57 ft.
Provided Volume
99063
Bottom Pool SA =
8.708 sq. ft.
Normal Pool SA =
12,400 sq. ft.
Vol. _
((N.P. SA + F.P. SA) 121 x (F-P. el. - N.P. el_)
=
31,662 cu. ft.
depth =
3 ft.
Flow for 5-day drawdown:
for 1st 1" of stormwater,
Q = Required State Vol. 1432,000 sec. (5-days)
= 0.070 cfs
rea Area or ripe for o-gay orawa
A= Q1[CdxSQRT(2xgxh)]
Cd = 0.6
9 = 32.2 ft-Is2
h = (F.P. elev. - N.P. elev.) 12
= 0.5 ft.
0.0207 sq, ft.
Diameter of Pipe for 5-day drawdown:
DIA. = SQRT[(A x 4) 1 pi]
= 0.1622 ft.
1.95 in.
OveraIIPONDmod 2 of 2

TE 99063
Leland Food Lion
Stormwater Project No. SW8 990802
New Hanover County
Engineer's Certification
I, _Phillip G. Triyp , as a duly registered Professional Engineer in the State of North
Carolina, having been authorized to observe (periodically/weerb4ft" ifae) the construction of the
project,
Leland Food Lion (Project)
far Z P No. 91, LLC (Project Owner) hereby state that, to the best of my abilities, due care
and diligence was used in the observation of the project construction such that the construction was
observed to be built within substantial compliance and intent of the approved plans and specifications.
Signature ���,�Sl02
Registration Number 17374 :� ��g14 •_CL
Date � C► �oz,' •• ''
RECEIVEg1
MAR 13 2003
DWQ
PROJ # :5,U 9,30 TUZ

812199
CDC
LEL.AND FOOD LION
Stormwater Calculations
Drainage Area
It. acres
Proposed develo meat 601,128 13,80
Total 601,128 13.80
% impervious - 0.479
= 47.9%
Use 49.0%
SStormwMo,r Calculations:
Time of Concentration:
Hydraulic Length (L) - 323 ft.
change in Height (H) = 1.75 ft.
Tc = (Lz 11 ),3as / 128
4.98 min.
Flow for 10 year, 6 hour Storm (010):
QPRE _ (CPRE) x (110) x (Area)
b 21.74 cfs
QPOST = (CPosr) x (Ila) x (Area)
= 51.29 cfs
Soil Storage Capacity for 10 year Storm:
CN = (81)(% imp.) + (49)(1-% imp.)
= 65
P = 4,80 in_ for 10 yr, 6 hr storm
S= 10MICN-10
5.38
Depth (D)= [P-(0.2)(S)1' I [P*(0.8)(S)1
= 1.52 in,
Time to Peak Flow:
Tp _ [(43.5)(D)(Area)1 I Q,o,PosT
17.01 min.
Detention Pond Design:
Pond Size:
Elevation
ft.)
Surface Area
. ft.
Normal Pool
34.50
33,258
State Flood Pool
35.50
35,861
C' Flood Pool
36,50
38,463
ITop of Bank
40,00
48,264
Bottom of Pool
28.50
19,371
Total Provided C', Store a Volume:
Vol. _ [(Normal pool SA + Flood Pool SA)121
x (F.P. elev. - N.P. elev.)
a 71,721 cu. ft.
City Storage Required for 10 year Storm:
TP = Vol. 1 (1.39)(Qp)
Vol, = (Tp)(1.39)(Qp)(60 sec.)
OP = 010,POST - 010,PRE
a 29.56 cfs
Vol- = 43,909 cu. ft.
-ITLmvious. Area
Land Use
sq. ft.
acres
Building area
49,500
1.14
As halt area
143,962
3.30
Concrete area
7,350
0.17
YOutparcels @ 85%
87.381
2.01
Total
288,193
6.62
CPRE = 0.25
CPosr = (% imp.)(.95)+(1 % imp.)(.25)
0.59
I,0 = 6.30 inlhr
15, = 7,79 in/hr
Flow for 50 year, 6 hour Storm (Qs0):
QPRE _ (CPRE) x (tso) x (Area)
= 26,88 cfs
QPOST = (CPov) x (150) x (Area)
= 63.43 cis
CN a (81)(% imp.) + (49)(1-1/6 imp.)
a 65
P = 6.42 in. for 50 yr, 6 hr storm
S = 10001CN - 10
= 5.38
Depth (D)- [P-(0.2)(S)]2I [P+(O.8)(S)]
a 2.66 in.
Time to Peak Flow:
Tp = [(43.5)(D)(Area)j 1 Q50,POST
25.19 min.
Pond side slopes = 3 :1
Depth below N.P. a 6 ft.
SAIDA = 0.0264
(Chart for 90% TSS Removal for Wet Detention
Pond without Vegetative Filter)
. ft.
State Volume Requirement for Storage of first V of runoff. -
Vol. _ [(1I12) x (DA) x (% imp.)] +
[(1112) x (DA) x (1-% imp.) x Cj
C = 0.2
= 29,232 cu. ft.
Provided Storage Volume for State Requirement:
State Vol. a 34,560 cu. ft.
Citv Storage Required for 50 vear Storm:
TP = Vol. I (1.39)(Qp)
Vol. _ (Tp)(1.39)(0p)(60 sec.)
Qp = 050.POST - 050.PRE
= 36,55 cfs
Vol. = 76,778 cu. ft.
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C4yPOND.xls 1 of 2

812199
CDC
re
LELAND FOOD LION
Stormwdter Calculations
Required Volume
Vol. a 20% of pond storage volume
31,577 cu.ft.
Outlet Structure Desian:
Flow for 2-day drawdown:
for 1st 1" of stormwate►,
4 = Required State Vol. / 172.800 sec. (2-days)
0.169 cfs
Required Area of Pipe for 2-day drawdown:
A= Q1[Cdx$QRT(2xgxh)]
Cd 0.6
9. 32.2 R.Is2
h = (F.P. elev.- N.P. elev.)12
0.5 ft.
A = 0,0497 s . ft.
Diameter of Pipe for 2-day drawdown
DIA. = SQRT[(A x 4)1 pi]
0.2515 ft.
a 3.02 in.
USE 2.5" ORIFICE
Outlet Structure Qh%k'
Using a 4' x 4' Basin,
Perimeter (L) = 16 ft.
4 = CIA
C = (% imp.)(.95) + (1-% imp.)(.25)
0.59
1. 6.30 in. for a 10 yr. Storm
A a 13.80 Acres
= 51.29 cfs
Q= CwxLxH"s
H a [Q ! (Cw x L)]Y"
Cw = 3
1.05 ft.
Peak elevation = Rood pool elevation + H
= 37.55 ft.
Provided Volume
Bottom Pool SA - 8,708 sq. ft.
Normal Pool SA - 12,400 sq. ft.
Vol. _ [(N.P. SA + F.P. SA)12] x (F.P, at. - N.P. at.)
31,662 cu. ft.
depth a 3 It.
Flow for 5-day drawdown:
for 1st 1" of stormwater,
Q = Required State Vol. 1432,000 sec. (5-days)
= 0,068 cfs
Required Area of Pipe for 5-day drawdown:
A= QI[CdxSQRT(2xgxh)]
Cd a 0.6
g . 32.2 ft.ls=
In = (F.P. elev. - N.P. elev.)12
a 0.5 ft.
A = 0.0199 sq, ft.
Diameter of Pipe for 5-day drawdown:
DIA. = SQRT[(A x 4)1 pi]
= 0.1591 ft.
1.91 in.
99063
CdyPOND.xls 2 of 2