SW8910405_HISTORICAL FILE_19910604

STORMWATER DIVISION CODING SHEET
POST -CONSTRUCTION PERMITS
PERMIT NO.
SW8 0 S
DOC TYPE
❑ CURRENT PERMIT
❑ APPROVED PLANS
HISTORICAL FILE
❑ COMPLIANCE EVALUATION INSPECTION
DOC DATE
Iggl 06 04-
YYYYMMDD

-- ,
State of North Carolina
Department of Environment, Health, and Natural Resources
Wilmington Regional Office
James G. Martin, Governor
Vlilliam W. Cobey, Jr., Secretary
June 4, 1991
DIVISION OF ENVIRONMENTAL MANAGEMENT
Mr. Thomas H. Nunalee, III, President
Cross Seed Company
Post Office Box 269
Wilmington, North Carolina 28402
Dear Mr. Nunalee:
Bob Jamieson
Regional Manager
Subject: Certification of Compliance
with Stormwater Regulations
Stormwater Project No. 910405
Cross Seed Company
New Hanover County
This Certification is pursuant to the application for
the Cross Seed Company received on April 9, 1991, with additional
information received on May 17, 1991. Based on our review of the
project plans and specifications, we have determined that the
stormwater control system complies with the Stormwater
Regulations set forth in Title 15A NCAC 2H.1003(i). The runoff
will be treated in a detention pond sized to achieve 90%
reduction in Total Suspended Solids.
This Certification shall be effective from the date of
issuance until rescinded. The project shall be constructed and
maintained in accordance with the plans and specifications
approved by the Wilmington Regional Office.
A professional engineer must certify that the
stormwater system has been installed in accordance with the
approved plans and specifications upon completion of
construction. The attached certification should be received
by this Office within 30 days of completion of construction.
Continued
127 Cardinal Drive Extension, Wilmington, N.C. 28405-3845 • Telephone [phone] • Fax [phone]
An Equal Opportunity Affirmative Action Employer

Mr. Nunalee
June 4, 1991
Page Two
----------------
If you have any questions concerning this matter, please
call Alexis Finn or me at [phone].
Sincerely,
-Dave Adkins
Water Quality Supervisor
DA/ai.f: 910405.JUN
cc: Mrs. Linda Phillips, Siteworks Design Group
Sky Conklin
John Parker, DCM
Bill Mills
Jim Herstine
Alexis Finn
CWiaming-to n-Regional=0,ff_ice�
Central Files

DIVISION OF ENVIRONMENTAL MANAGEMENT
Evaluation of Stormwater Treatment and Disposal System
Draining to Waters Other Than Class SA
PROJI':CT DATA
Project Name: Cross Seed Company
Project No.: 910405
Location (County, Township/Municipality, Address):
New Hanover County
Applicant Name: Mr. Thomas H. Nunalee, III, President
Mailing Address: Post Office Box 269
Wilmington, North Carolina 28402
Submittal.Date: April 9, 1991
Water Body Receiving Stormwater Runoff: Smith Creek
Classification of Water Body: "C Swamp"
WET DETENTION POND EVALUATION
1. Yes No The design storage is for the runoff from all
impervious surfaces resulting from 1-inch of
rainfall and is located above the permanent
pool.
2. Yes No The permanent pool is designed for 90% TSS
removal. Therefore, no vegetative filter is
required.
3. Yes No The runoff completely draws down to the
permanent pool in 5 days, but not less than 2
days.
4. Yes No The mean depth of the permanent pool is a
minimum of 3 feet;.
5. Yes No The inlet structure is designed to minimize
turbulence and short circuiting.
6. Yes No An appropriate operation and maintenance plan
has been provided for the system.
Continued

WET DETENTION POND EVALUATION CONTINUED
7. Yes No THIS PROJECT MEETS THE STORMWATER CONTROL
REQUIREMENTS OF 15A NCAC 2H.1003 (g), (i), (k),
and (1) (For Yes, 1 through 7 must all be
circled Yes.)
Brief Explanation: The surface area of this detention pond has
been designed to remove 90% TSS without the aide of a vegetative
filter.
DIVISION OF ENVIRONMENTAL MANAGEMENT SIGN -OFF
Wilmington Regional Office
l � i
Date Individual Evaluating Form/Plans
7
D
fti e f;'
cc: Applicant/WiRO/Mills/CF
Water ,Quality egional Supervisor

/ ITEWORKS
-S Design Group, P.A.
May 16 1991
Ms. Alexis Finn
127 Cardinal Dr. Ext.
Wilmington, NC 28405
RE: Cross Seed Additional Information
File # 91015-9
Dear Alexis:
919/799-6808
I received your letter of May 8, 1991. Your questions are
answered below. Two sets of revised prints are included.
1. Storm water is routed to the pond from the gravel area
and part of the building by the swale on the northeast property
line and by a Swale built into the pavement on the northwest
asphalt. Sheet flow occurs from -the paved area and enters the two
swales that lead to the pond. W�� s_ �(��'';'
2. The concrete swale is extended to 33.8 MSL�and rip rap
�531 is added at the outlet.
sp. 101(.S <y 3. As discussed, there are 2 separate pond calculations.
In talking with Larry, we have decided to build a pond now to
1.95"'0, 4L.accept the future impervious area.
4. Wetlands do not exist.
5. Receiving stream characteristics - See attached sheet.
If you have any other questions, please do not hesitate to
call.
Sincerely,
SITEWORKS DESIGN GROUP, P.A.
?� I
y
,J,0*1
D E M 1(b
PROJ # g/oyoS
4006 Oleander Dr., Suite 3 0 P.O. Box 3988 0 Wilmington, North Carolina 28406-3988

�s-15-9/ 9/alS FICA Ve%/i4
1. I-055 ,.:;c: c. Q� C5
Area = 31.5 s-F
We4cc( ffrimefer, P, = l77'
slope = 1. 3Co %
n = „ D 3 C Heavy �ecJefafeo��
r
14 r z/?
2Cp8 CPS CE�risfin�r%
Y = A = si. S = F, S Fps CExr's>S'nq
There are gees onJ underbrush gYowinq along
-Ae honks o-F -lhe di fch. The Plan) clear1,y shows
fha-F the clearing wll no-t ol/sfur/J- Jgrisfi'nJc
vgei afi'on on Jei+her ,lcle o-F fhe d'fch For a
Jisfance o-F a-f leas+ V 1r-cm -!he censer of -Me

--1-
7-
F
DEL-]
L
+-li
711
i
I
T-

State of North Carolina
Department of Environment, Health, and Natural Resources
Wilmington Regional Office
James G. Martin, Governor
William W. Cobey, Jr., Secretary
May 8, 1991
DIVISION OF ENVIRONMENTAL MANAGEMENT
Mrs. Linda Lewis
Siteworks Design Group
Post Office Box 3988
Wilmington, North Carolina 28406-3988
Subject: Additional Information
Stormwater Project No. 910405
Cross Seed Company
New Hanover County
Dear Mrs. Lewis:
Bob Jamieson
Regional Manager
The Wilmington Regional Office received a Stormwater
Management Plan for the Cross Seed Company on April 9, 1991.
A preliminary review has determined that the submittal for the
subject project is not complete. The following information is
needed to continue the stormwater review:
1. How is stormwater runoff being routed from the building
and parking areas to the detention pond?
2. This Office recommends extending the concrete inlet
swale to 2 ft. below the NWL, e.g. 33.8' MSL and the
addition of rip rap.
3. Please check your calculations of the following values.
A discrepancy exists in our calculations of the
following:
a. Required SA of the permanent pool = 11592 sf
b. 1.0" < orifice < 1.6"
4. If applicable, delineate wetlands and provide U.S. Army
Corps of Engineers documentation. If wetlands do not
exist, please indicate in writing.
5. Provide receiving stream characteristics.
Continued
127 Cardinal Drive Extension, Wilmington, N.C. 28405-3845 • Telephone [phone] • Rtx 919-350-2004
An Equal Opportunity Affirmative Action Emolover

�iScroF rc..l @ �.OP AM pooQ

Mrs. Lewis
May 8, 1991
Page Two
This information should be received by this office no later
than June 10, 1991, or your project will be returned as
incomplete.
Construction of the subject project may not commence
prior to approval of the Stormwater Management Plan. If you have
any questions, you may call me at telephone number (919)
395-3900.
Sincer ly,
Ms. Alexis I. Finn
Environmental Engineer
AIF: 910405.MAY
cc: c(_2_)_Arexs-Fnn�:7
Bill Mills
Central Files

ITEWORKS
Ail S Design Group, P.A.
April 8, 1991
Ms. Alexis Finn
DEHNR
127 Cardinal Dr. Ext.
Wilmington, NC 28405
RE: Cross Seed Co. Site Plan
File u 91015-5
Dear Alexis:
919/799-6808
Attached for your review are 2 grading plans, calculations,
the Operation and Maintenance manual, and the signature
authorization form. A copy of the topography map used to
calculate the off -site drainage is also included.
A copy of this plan and the required information is filed
with Jim Craig of New Hanover County for Erosion Control
approval.
If you need more information, please do not hesitate to
call.
Sincerely,
SITTEWORKS DESIGN GROUP, P.A.
OC,fi»Gta��
Linda Lewis
jECEIVE0
1991
ap^ ci •®
DEM
PiOj if roNo�
4006 Oleander Dr., Suite 3 0 P.O. Box 3988 ■ Wilmington, North Carolina 28406-3988

Division of Enviromental Management
7225 Wrightsville Ave.
Wilmington, NC 28403
RE: Stormwater Signature Authorization
File 0 91015
TO: D.E.M.
1, Cross Seed Company, the
stormwater review, hereby grant
signature of authority to submit
stormwater review.
Sincerely,
44vr4-4 --
---------- -----
THOMAS H. NLNALEE, 111 PRESIDENT
owner of the property under
Siteworks Design Group, P.A.
plans and calculations for
I, ( ()j2 a Notary Public of the County of
_ State of North Carolina, hereby certify
that personally before me this day and under
oath acknowledge that the above form was executed by him.
Witness my han and notarial seal this �_ day of
My commissiofn� expires VU1�go2_
Signature _—
�]) ECE 9 1'/ LS �rl
ILfn�( APP 1 191 U
DEM
PRpJ g10yoS

Data for CROSS SEED CO. 91015
Prepared by SITEWORKS DESIGN GROUP, P.A. 2 Apr 91
HVdroCAD Release 2.51 (c) 1986-1990 Applied Microcomputer Systems
SUBCATCHMENT 1 to 9999
RUNOFF BY RATIONAL METHOD: DURATION= 10 MIN INTEN= 6.40 IN/HR
SUBCAT
AREA
LEN SLOPE. Tc
WGT'D
PEAK
NUMBER
(ACRE)
(FT) (0) (MIN)
--- GROUND COVERS (0CN) ---
CN C
(CFS)
1
1.00
- - 5
100000 - -
- - .90
5.9
2
.30
- - 16
100000 - - -
- .35
.3
3
.30
- - 7
100000 - -
- - .90
1.6
4
1.10
- - 10
100000 - - -
- .90
5.2
5
.40
- - 11
100 000 - -
- - .35
.7
6
.20
- - 4
100000 - -
- - .90
1.2
7
.30
- - 18
100000 - -
- - .35
.3
8
5.00
- - 30
100000 - -
- - .25
2.2
9
17.50
- - 22
100000 - -
- - .50
21.0
10
2.50
- - 9
100000 - -
- - .85
11.3
11
.16
- - 5
100000 - -
- - .90
1.0
FJUIS��A �•� �Ii1
APR 9 199. U
DEM
PROJ W lLQgD�

Data for CROSS SEED CO. 91015
Prepared by SITEWORKS DESIGN GROUP, P.A. 2 Apr 91
HydroCAO Release 2.51 (c) 1986-1990 Apvlied Microcomputer Systems
REACH 1 to 9999
REACH
ROUTING BY
STOR-IND METHOD
REACH
BOTTOM
SIDE
PEAK
CONTACT
PEAK
NO.
DIAM
WIDTH DEPTH
SLOPES
n
LENGTH
SLOPE
VEL.
TIME
Qout
(IN)
(FT) (FT)
(FT/FT)
(FT)
(FT/FT)
(FPS)
(SEC)
(CFS)
1
-
- 1.2
.33 .33
.020
510
.0050
2.8
185
5.1
2
-
- 1.0
.33 .33
.013
115
.0280
7.6
15
6.6
3
-
- 1.0
.33 .33
.020
210
.0050
:2.9
73
6.1
4
24.0
- -
- -
.013
30
.0050
2.0
15
.1
5
36.0
- -
- -
.013
110
.0136
11.0
10
35.1
6
36;0
- -
- -
.013
105
.0136
11.0
10
35.8
7
-
- 1.0
.33 .33
.020
340
.0050
1.7
197
.8
veloa'-h'es in bgrcwr A{ sweles,
h=-Oz

Data for CROSS SEED CO. 91015
Prepared by SITEWORKS DESIGN GROUP, P.A. 27 Mar 91
HydroCAD Release 2.51 (c) 1986-1990 Applied Microcomputer Systems
REACH 1 to 9999
REACH
ROUTING BY
STOR-IND METHOD
REACH
BOTTOM
SIDE
PEAK
CONTACT
PEAK
NO.
DIAM
WIDTH DEPTH
SLOPES
n LENGTH SLOPE
VEL.
TIME
Qout
(IN)
(FT) (FT)
(FT/FT)
(FT) (FT/FT)
(FPS)
'(SEC)
(CFS)
1
-
- 1.2
.33 .33
.030 510 .0050
2.0
256
4.7
2
-
- 1.0
.33 .33
.013 115 .0280
7.6
15
6.1
3
-
- 1.0
.33 .33
.030 210 .0050
2.1
100
5.9
4
24.0
- -
- -
.013 30 .0050
2.0
15
.1
5
36.0
i
- -
- -
.013 110 .0136
11.0
10
35.1
6
36.0
- -
- -
.013 105 .0136
11.0
10
35.8
Ve/aciii'es in
5awne� /ii��i�q
5u�a�es
7 =. o3

Data for CROSS SEED CO. 91015
Prepared by SITEWORKS DESIGN GROUP, P.A. 24 Mar 91
HydroCAD Release 2.51 (c) 1986-1990 Applied Microcomputer Systems
POND 1 to 9999
POND ROUTING BY STOR-IND METHOD
POND OUTLET SPECIAL START
FLOOD
PEAK PEAK
Qpeak
Qpeak
Qpeak
NO. DEVICES OUTLETS ELEV.
ELEV.
ELEV. STORAGE
ATTEN.
LAG
OUT
(FT)
(FT)
(FT) (AF)
(o)
(MIN)
(CFS)
1 2 - 35.8
38.6
36.8 .22
99
21.1
.1

Data for CROSS SEED CO. 91015
Prepared by SITEWORKS DESIGN GROUP, P.A. 26 Mar 91
HydroCAD Release 2.51 (c) 1986-1990 Applied Microcomputer Systems
POND 1 to 9999
POND 1 POND 1
STARTING ELEV= 35.8 FT
FLOOD ELEV= 38.6 FT
ELEVATION CON.AREA INC.STOR CUM.STOR
(FT) (SF) (CF) (CF)
35.8 8888 0 0
37.2 10351 13454 13454
38.6 11882 15551 29005
STOR-IND METHOD
PEAK ELEVATION= 36.8 FT
PEAK STORAGE = 9366 CF
Qin = 13.6 CFS @ 10.19 HRS
Qout= .1 CFS @ 10.54 HRS
ATTEN= 99 96 LAG= 21.1 MIN
IN/OUT= .22 / .06 AF
INVERT (FT) OUTLET DEVICES
35.8' 1.7" ORIFICE
Q=.6 PI r^2 SQR(2g) SQR(H-r)
37.2 9' SHARP -CRESTED WEIR
Q=C L H^1.5 C=3.27+.4 H/l L=Length-2(.1 H)
TOTAL
DISCHARGE vs
ELEVATION
FEET
0.0
.1
.2 .3
.4 .5
.6
.7
'.8 .9
35.8
0.0
0.0
0.0 0.0
0.0 0.0
.1
.1
.1 .1
36.8
.1
.1
.1 .1
.1 1.0
2.8
5.1
7.8 11.0
37.8
14.6
18.5
22.8 27.4
32.4 37.7
43.3
49.2
55.4

Data for CROSS SEED CO. 91015
Prepared by SITEWORKS DESIGN GROUP, P.A. 24 Mar 91
HydroCAD Release 2.51 (c) 1986-1990 Applied Microcomputer Systems
POND 1 to 9999
POND 1
HOUR
10.00
11.00
12.00
13.00
14.00
15.00
16.00
17.00
18.00
19.00
20.00
13
12
11
10
9
8
7
6
4
3
2
POND 1 INFLON & OUTFLOW
POND 1
STOR—IND METHOD
PERK ELEV= 36.9 FT
PERK STOR= 9365 CF
Qin= 13.6 CFS
Qout= .1 CFS
LAG= 21.1 MIN
0i CD V Ln CD r�
TIME (hours)
POND 1
OUTFLOW PEAK= .1 CFS @ 10.54 HOURS
CC) Ol CD
N
0.0
0.0
.1
.1
.1
.1
.1
.1
.1
.1
.1

., 1
Data for CROSS SEED CO. 91015 FUTURE DEVELOPMENT Page 1
Prepared by SITEWORKS DESIGN GROUP, P.A. 26 Mar 91
HydroCAD Release 2.51 (c) 1986-1990 Applied Microcomputer Systems
SUBCATCHMENT 1 to 9999
RUNOFF BY RATIONAL METHOD: DURATION= 10 MIN INTEN= 6.40 IN/HR
SUBCAT
AREA LEN
SLOPE Tc
WGT'D
PEAK
NUMBER
(ACRE) (FT)
(96) (MIN)
--- GROUND COVERS (96CN)
--- CN C
(CFS)
1
1.00 -
- 5
100 WO - -
- - .90
5.9
2
.30 -
- 16
100%00 - -
- - .35
.3
3
.30 -
- 7
1009600 - -
- - .90
1.6
4
1.10 -
- 10
100-%00 - -
- - .90
5.2
5
.40 -
- 11
1009600 - -
- - .35
.7
6
.20 -
- 4
1009600 - -
- - .90
1.2
7
.30 -
- 18
100-%00 - -
- - .35
.3
8
5.00 -
- 30
100.%00 - -
- - .25
2.2
9
17.50 -
- 22
100-%00 - -
- - .50
21.0
10
2.50 -
- 9
1009600 - -
- - .85
11.3
11
1.10 -
- 10
1009600 - -
- - 1.90
5.2
n
Ll
ILIj��\l APR 9
JD_ EM
PROF F� /0q0s-

Data for CROSS SEED CO. 91015 FUTURE DEVELOPMENT
Prepared by SITEWORKS DESIGN GROUP, P.A. 27 Mar 91
HydroCAD Release 2.51 (c) 1986-1990 Applied Microcomputer Systems
REACH 1 to 9999
REACH
ROUTING BY
STOR-IND METHOD
REACH
BOTTOM
SIDE
PEAK
CONTACT
PEAK
NO.
DIAM
WIDTH DEPTH
SLOPES
n
LENGTH
SLOPE
VEL.
TIME
Qout
(IN)
(FT) (FT)
(FT/FT)
(FT)
(FT/FT)
(FPS)
(SEC)
(CFS)
1
-
- 1.2
.33 .33
.030
510
.0050
2.1
239
6.4
2
-
- 1.0
.33 .33
.013
115
.0280
8.1
14
8.2
3
-
- 1.0
.33 .33
.030
210
.0050
2.2
95
7.9
4
24.0
- -
- -
.013
30
.0050
2.9
10
1.1
5
36.0
- -
- -
013
110
.0136
11.6
9
46.6
6
36.0
- -
- -
.013
105
.0136
11.7
9
47.4

Data for CROSS SEED CO. 91015 FUTURE DEVELOPMENT Page 3
Prepared by SITEWORKS DESIGN GROUP, P.A. 26 Mar 91
PxidrnrAn Ralaaca 7 51 (r) 1QAFi-iaon Annlind lAirrnrnmmitar Cvctownc
POND 1 to 9999
POND ROUTING BY STOR-IND
METHOD
POND OUTLET SPECIAL START
FLOOD
PEAK
PEAK
Qpeak
Qpeak
Qpeak
NO. DEVICES OUTLETS ELEV.
ELEV.
ELEV.
STORAGE
ATTEN.
LAG
OUT
(FT)
(FT)
(FT)
(AF)
(6)
(MIN)
(CFS)
1 2 - 35.6
38.2
36.9
.30
99
20.5
.1

Data for CROSS SEED CO. 91015 FUTURE DEVELOPMENT
Prepared by SITEWORKS DESIGN GROUP, P.A.
N\/rlrnrAn Roloaco 9 m (r) laAA-loon Annliorl Mirr
POND 1 to 9999
POND 1 POND 1
STARTING ELEV= 35.6 FT
FLOOD ELEV= 38.2 FT
ELEVATION CON.AREA INC.STOR CUM.STOR
(FT) (SF) (CF) (CF)
35.6 9032 0 0
37.2 10714 15778 15778
38.2 11844 11274 27052
Page 4
26 Mar 91
STOR-IND METHOD
PEAK ELEVATION= 36.9 FT
PEAK STORAGE = 12984 CF
Qin = 18.8 CFS @ 10.18 HRS
Qout= .1 CFS @ 10.52 HRS
ATTEN= 99 96 LAG= 20.5 MIN
IN/OUT= .30 / .07 AF
INVERT (FT) OUTLET DEVICES
35.6 1.8" ORIFICE
Q=.6 PI r^2 SQR(2g) SQR(H-r)
37.2 9' SHARP -CRESTED WEIR
Q=C L H^1.5 C=3.27+.4 H/l L=Length-2(.1 H)
TOTAL DISCHARGE vs ELEVATION
FEET
0.0
.1
.2
.3
.4 .5
.6
.7 .8 .9
35.6
0.0
0.0
0.0
0.0
0.0 .1
.1
.1 .1 .1
36.6
.1
.1
.1
.1
.1 .1
.1
1.0 2.8 5.1
37.6
7.9
11.0
14.6
18.5
22.8 27.5
32.4
37.7

Data for CROSS SEED CO. 91015 FUTURE DEVELOPMENT
Prepared by SITEWORKS DESIGN GROUP, P.A. 27 Mar 91
HvdroCAD Release 2.51 (c) 1986-1990 Applied Microcomputer Systems
POND i to 9999
POND 1 POND 1
STARTING ELEV= 35.6 FT
FLOOD ELEV= 38.2 FT
ELEVATION CON.AREA INC.STOR CUM.STOR
(FT) (SF) (CF) (CF)
35.6 9032 0 0
37.2 10714 15776 15778
38.2 11844 11274 27052
STOR-IND METHOD
PEAK ELEVATION= 37.3 FT
PEAK STORAGE = 16997 CF
Qin = 25.1 CFS @ 10.18 HRS
Qout= 1.2 CFS @ 10.43 HRS
ATTEN= 95 96 LAG= 14.6 MIN
IN/OUT= .40 / .11 AF
INVERT (FT) OUTLET DEVICES
35.6 1.8" ORIFICE
Q=.6 PI r^2 SQR(2g) SQR(H-r)
37.2 9' SHARP -CRESTED WEIR
Q=C L H^1.5 C=3.27+.4 H/1 L=Length-2(.1 H)
TOTAL DISCHARGE vs ELEVATION
FEET
0.0
.1
.2
.3
.4
.5
.6
.7 .8 .9
35.6
0.0
0.0
0.0
0.0
0.0
.1
.1
.1 .1 .1
36.6
I
.1
.1
.1
.1
.1
.1
.1
1.0 2.8 5.1
37.6
7.9
11.0
14.6
18.5
22.8
27.5
32.4
37.7

,E
` JOB re; ! __C?•
SITEWORKS DESIGN GROUP SHEET NO. ' OF
P.O. Box 3988 CALCULATED BY �12Lf DATE 3-27 9r
WILMINGTON, NORTH CAROLINA 28406
[phone] CHECKED BY DATE
SCALE
RIOOIICI7a1�4s,OMIn.Wp. %IIl, topaz M1gNETOLLiPEF FIOPtlSNEO

SITEWORKS DESIGN GROUP
P.O. Box 3988
WILMINGTON, NORTH CAROLINA 28406
[phone]
D
ADD
SHEET NO.
`�
OF
CALCULATED BY
14•j' L
q
DATE
CHECKED BY
DATE
SCALE
M 4oRii X
J�
7S61�wa Mal. ie�M Tmntm IJmOSdeE

J0B �,v;sCo. 91 DI
SITEWORKS DESIGN GROUP SHEET NO. /]� OF
P.O. Box 3988 CALCULATED BV A 2l_ —DATE -�-ZS - 9�
WILMINGTON, NORTH CAROLINA 28406
[phone] CHECKED BY DATE
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JOB
SITEWORKS DESIGN GROUP SHEET NO. OF
P.O. Box 3988 CALCULATED BY DATE
WILMINGTON, NORTH CAROLINA 28406
[phone] CHECKED BY DATE
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SITEWORKS DESIGN GROUP
P.O. Box 3988
WILMINGTON, NORTH CAROLINA 28406
[phone]
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SHEET NO. p5 OF
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CALCULATEDBV , pa— DATE 9'
CHECKED BY DATE
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OPERATION & MAINTENANCE MANUAL
Cross Seed Company Site
Project #91015
1. Description
The Stormwater detention system consists of a detention
pond, and regulated outflow device. The pond is
approximately 10000 square feet in area and 4.5 feet deep at
the normal water level, and will be graded at 3:1 and
protected by aquatic vegetation.
Outflow from the pond is regulated by a concrete outlet
structure. The regulating device is a 1-3/4" orifice in one
side of the concrete box at the normal pool level of 35.8.
This opening allows the 1" runoff volume to escape the pond
in 2 days.
2. Operation
The purpose of the stormwater detention system is to
collect and store the runoff from the first inch of rainfall
on the site, allow sediment to settle out of the runoff and
discharge the stored water over a 2 to 5 day period The
methods by which this occur do not require operator
attention, other than maintenance requirements.
Stormwater runoff flows by gravity to the pond. For
rainfalls of 1" or less the pond will rise up to 1.4 feet
and drop back down over a 2 to 5 day period as water
discharges through the 1-3/4" diameter hole. For.rainfalls
greater than 1", once the water level rises by 1', it will
flow over the weirs around the concrete box, and discharge
thru a 24" RCP from the system. All stormwater receives some
degree of settling and treatment, but the rainfall in excess
of 1" discharges much sooner.
ECEIVED
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3. Maintenance
Routine maintenance will be required to keep the pond
operating as designed.
Each runoff producing rain:
1. Check orifice and concrete box and remove any
trash.
2. Check areas around swales for erosion. Make
repairs promptly.
Weekly:
.1. Remove trash from pond slopes.
Quarterly:
1. Pond depth should be measured to check
sediment levels. Normal depth is 4.5 feet.
Sediment removal'is.necessary when depth is
3.5 feet. Sediment should be removed with a
backhoe, being careful no to damage the pond
slopes.
2. Check grassed areas around pond for erosion.
Repairs should be made promptly.
4. Responsibility
Cross Seed Company, owner will be responsible for
routine maintenance of the system, and the complete
restoration of any failed, damaged or deteriorated
components.
I, Tom Nunilee, have read and understand the intent of
this document.
Signature ° a'��`7i Date
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