SW8940120_HISTORICAL FILE_19991130 (2)

STORMWATER DIVISION CODING SHEET
POST -CONSTRUCTION PERMITS
PERMIT NO.
SW8 614ok'ap
DOC TYPE
❑ CURRENT PERMIT
❑ APPROVED PLANS
X HISTORICAL FILE
❑ COMPLIANCE EVALUATION INSPECTION
DOC DATE
l 9 4 911,56
YYYYMMDD

TRIPP ENGINEERING, P.C.
419 Chestnut Street
Wilmington, North Carolina 28401
Phone: [phone] • FAX: [phone]
LETTER OF TRANSMITTAL
Job �No. Vu Jq
To: Iv� L/N Date:(v'
Attention: L1ylax� Low15 Subject:14Porgy
_ FAX TRANSMITTAL: NUMBER OF PAGES INCLUDES COVER _
I am sending you: (ATTACHED ( ) UNDER SEPARATE COVER
( ) Prints ( ) Tracings ( ) Copy of letter ( ) Specifications ( ) Other
These are transmitted as checked below:
( )'For Approval ( ) For Your Use ( ) Sign & Return ( ) Review
Remarks:
cc:
Signe ._
c

STATE OF NORTH CAROLINA, Department of Environmental Quality,
127 Cardinal Drive Extension, Wilmington, North Carolina 28405 [phone]
FILE ACCESS RECORD
DEQSECTION: •DEA&t_2 Sf..) REVIEW TIME/
NAME: I EMAIL: J� '►(mot I q co Y1i
REPRESENTING:' PHONE:
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out our day-to-day program obligations. Please read carefully the following guidelines signing the form:
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$500.00. No briefcases, large totes, etc. are permitted in the file review area.
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an offsite location at your expense. Large plan copies needed should be attached on top of the file. Allways Graphics
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7. In accordance with General Statue 25-3-512, a $25.00 processing fee will be charged and collected for checks on which
payment has been refused.
FACILITY NAME
I. 5W� �N0120 Jei�M far-�.c�
z. E Zoy,_i
3.
4.
5.
COUNTY
, ',T�►c IZ 05 Lq ' ' 1 s q i 3'o
rignaturVanidme of Firm/Business Date M/DD/YY Time In Time Out
of
COPIES MADE PAID
INVOICE
G:/ADM/Shared/File Review Access Form rev 2018

7/22199
CDC
JERRY PORTER EXPANSION
Stormwater Calculations
99059
Total Drainage Area
R. acres
181.210 1 4.18
Im orMAMs Area
Land Use
sq.R.
acres
buildings
8,092
0.19
parkinglasphaft
144,141
3.31
concrete
365
0.01
1
Total
1 152.598
3.50
Stormwater Calculations:
Time of Concerdrelion
Hydraulic Length (L) = 783 R.
change In Heigh (H) = 3 ft.
To = (L0 /11).3" / 128
11.26 min.
Flow for 10 year, 6 hour Stonn (010)
OPRE • (CPRE) x (110) x (Area)
= 6,55 cfs
OPosr • (Cmv) x (110) x (Area)
22.01 cfs
Son
CN = (98)(% imp.) + (60)(1-% imp.)
93
P = 4.82 in. forlOyr, 6 hr storm
S = 1000/CN - 10
= 0.75
Depth (D)= [P-(0.2)(S)j21 [P+(0.8)(S)j
= 4.02 in.
Time to Peak Flow:
TP = [(43.5)(D)(Area)I / 02,Posr
33.05 min.
Detention Pond Design:
Pond Size:
Elevation
R.
Surface Area
(sq. ft.
Normal Pool
1 35.00
7,781
Flood Pool
38.70
9.632
Top of Benk
38.00
11,160
Bottom of Pool
28.50
2,430
Provided Storage Volume:
Vol.v[(Normal pool SA + Flood Pool SA)121
x (F.P. elev. - N.P. elev.)
14,801 cu. R.
% impervious = 0.842
84.2%
say 85.0%
CPRE0.25
CPom= (% imp.)(.95)+(1-% imp.)(.25)
0.84
Ir0 • 6.30 in/hr
1250 7.13 in/hr
Flow for 25 year, 6 hour Storm (025)
OPRE' (CPRE) x (125) ■ (Area)
7.42 cfs
OPosr • (CPosr) x (125) x (Area)
24.92 cis
CN = (98)(% imp.) + (60)(1 -%imp.)
93
P = 5.71 in. for 25 yr, 6 hr stomr
S = 1000/CN - 10
0.75
Depth (0)' (P-(0.2)(S)12 / [P+(0.8)(S)l
Time to Peak Flow:
TP n [143.5)(D)(Area)j / Oro,Posr
35.56 min.
5AWA = V.l14jv
(Chart for 90%TSS Removal for Wet Detention
Pond without Vegetative Filter)
State Volume Reouired for Stereos of first 1' of runoff
Vol.- [(V12) x (DA) x (% imp.)) +
[(1112) x (DA) x (l-% imp.) x CI
C = 0.2
13,193 cu. R.
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99059POND.xis 1 of 2 1 IV'-- ^ ^I

7/22/99 JERRV PORTER EXPANSION
CDC Stomlwe[er Calculations
Pond Volume:
Bottom SA = 2,430 sq. ft.
Normal Pool SA = 7,781 sq. R.
Vol. • [(N.P. SA + Bottom SA) / 21 x (N.P. el. - Bottom el.)
33,186 cu. R. _
o F
Required Volume
Vol. • 20% of storage volume
8,637 cu. R.
;dRi['bi'TiTn1Rt:7�`:F7 r r
Flow for 2-day drawdown:
for 1st 1' of stormwator,
Q = Required Vol. / 172,800 sec. (2-days)
0.076 cfs
Required Area of Pipe for 2-day drawdown:
A- Q/ [Cd x SQRT(2 x g x h)]
Cd - 0.6
g • 32.2 R./s2
h - (F.P. elev.- N.P. elev.) /2
0.85 R.
A = 0.0172 sq. R.
Diameter of Islas for 2-day drawdown
DIA. • SORT[(A x 4) / pij
0.1480 R.
1.78 in.
'Use: 1.75 in diameter pipe
Outlet Structure Check:
Using a 4' x 4' Basin,
Perimeter (L) = 18 R.
Q = CIA
C = (% imp.)(.M + (1-% impJ(.25)
0.84
1 = 7.13 in. for a 25 yr. Storm
A = 4.16 Acres
24.92 cfs
Q• Cwx LxH s
H = [Q / (Cw x L)I�O
Cw = 3
0.65 R.
Peak elevation = flood pool elevation + H
37.35 R.
Provided Volume
Bottom SA -
1,330 sq. R.
Normal Pool SA •
3,085 sq. R.
Vol. _
[(N.P. SA+ Bottom SA) / 21 x (N.P. el. - Bottom el.)
8,623 cu. R.
depth =
3 R.
Flow for 5-day drewdown:
for 1st 1' of stormwater,
Q = Required Vol. / 432,000 sec. (5days)
0.031 cfs
Required Area of Pipe for 5-day drawdown:
A- Q/[CdxSQRT(2xgxh)[
Cd - 0.6
g • 32.2 R./52
h - (F.P. elev. - N.P. olev.) / 2
• 0.85 R.
A = 0.0089 s . R.
Diameter of Pipe for 5d2drawdown:
DIA. = SORT((A x 4) / pi[
0.0936 R.
.12 In.
99059POND.xis 2 of 2

TRIPP ENGINEERING, P.C.
419 Chestnut Street
Wilmington, North Carolina 28401
Phone: [phone] • FAX: [phone]
October 22, 1999
NCDENR
Division of Environmental Management
Water Quality Section
127 Cardinal Drive
Wilmington, NC 28405-3845
Attn: Ms. Linda Lewis
Re: Jerry Porter Lincoln Mercury Isuzu
SW8 940120 Modification
New Hanover County, NC
T99059
Dear Linda:
OCT 2 5 1999
In response to your additional information request letter, dated September 20, 1999,
we offer the following:
I . The math error has been corrected.
2. The cleanout depths for the O & M agreement have been revised.
I The outlet structure has been labeled.
4. An additional site plan with highlighted drainage areas has been enclosed.
5. All Correspondence is labeled with the project # SW8 940120.
6. The forebay wall elevation has been raised between DI-2 and the outlet structure to
help with short circuiting of the pond.
7. Dimensioning of the pond has been included.
Please contact us with questions or comments, or if you require additional information.
Thank you.
Sincerely,
'T/ripp En ineering, P.
Charles 1). Cazier, E.I.
CDC:dcb
Enc.

State of North Carolina
Department of Environment
and Natural Resources
Wilmington Regional Office
James B. Hunt, Jr., Governor
Bill Holman, Secretary
Division of Water Quality
September 20, 1999
Mr. Jerry Porter
Jerry Porter Lincoln, Mercury, Isuzu
5501 Market Street
Wilmington, NC 28405
U
sw�®
NCDENR
NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
Subject: ACKNOWLEDGMENT OF RECEIPT AND
REQUEST FOR ADDITIONAL INFORMATION
Stormwater Project No. SW8 940120 Modification
Jerry Porter Lincoln Mercury Isuzu
New Hanover County
Dear Mr. Porter:
The Wilmington Regional Office received a Stormwater Management Permit Application for Jerry
Porter Lincoln Mercury Isuzu on July 27, 1999. A preliminary review of that information has determined that
the application is not complete. The following information is needed to continue the stormwater review:
There is a math error in the reported amount of built -upon area. Please correct the total.
2. The sediment cleanout elevations on the O & M are backwards. The numbers that are supposed
to go in the blanks are the larger numbers, ie., 75% of the design depth. If you put in the smaller
number, you are incorrectly allowing the depth to be reduced to an amount equivalent to 25%
of the design depth.
Please label the outlet structure on the plans.
Please provide a plan which includes the entire drainage area, highlighted, and which shows all
the development previously permitted, including existing grades.
5. Please reference the project number above on all correspondence.
6. Please create a longer flow path for the runoff from DI-2 by raising the elevation of the top of
the forebay wall between DI-2 and the outlet structure. Short-circuiting is a concern.
Please provide dimensions for ALL sides of the pond.
127 Cardinal Dr. Ext., Wilmington, North Carolina 28405 Telephone [phone] FAX [phone]
An Equal Opportunity Affirmative Action Employer 50% recycled/10% post -consumer paper

Mr. Porter
September 20, 1999
Stormwater Project No. S W8 940120 Modification
Please note that this request for additional information is in response to a preliminary review. The
requested information should be received by this Office prior to October 20, 1999, or the application will be
returned as incomplete. The return of a project will necessitate resubmittal of all required items, including the
application fee. The Division is allowed 90 days from the receipt of completed application to issue the permit.
The construction of any impervious surfaces, other than a construction entrance under an approved
Sedimentation Erosion Control Plan, is a violation of NCGS 143-215.1 and is subject to enforcement action
pursuant to NCGS 143-215.6A.
If you have any questions concerning this matter please feel free to call me at [phone].
Sincerely,
Linda Lewis
Environmental Engineer
RSS/arl: S:\WQS\STORMWAT\ADDINFO\940120.SEP
cc: Linda Lewis
Phil Tripp, P.E.
127 Cardinal Dr. Ext., Wilmington, North Carolina 28405
An Equal Opportunity Telephone 9d/I0%-3900 sum 9paper -2004
q pportunit Affirmative Action Employer 50% recycled/]0% post -consumer paper

2. If this application is being submitted as the result of a renewal or modification to an existing permit, list
The existing permit number SW8 940120 and its issue date (if known) I/23/99
3. Specify the type of project (check one):
_ Low Density X High Density Redevelop
4. Additional Project Requirements (check applicable blanks):
CAMA Major X Sedimentation/Erosion Control
General Permit Other
404//401 Permit NPDES Stormwater
Information on required state permits can be obtained by contacting the Customer Service Center at
1-877-623-6748.
III. PROJECT INFORMATION
1. In the space provided below, summarize how stormwater will be treated. Also attach a detailed narrative
(one to two pages) describing stormwater management for the project.
stormwater detention pond
2. Stonnwater runoff from this project drains to the Cape Fear River basin.
3. Total Project Area: 4.16_ acres
4. Project Built Upon Area: 84.2 %.
5. How many drainage basins does the project have? 1_
6. Complete the following information for each drainage area. If there are more than two drainage areas in the
project, attach an additional sheet with the information for each area provided in the same fonnat as below.
Tiashi"Irifortna "on'
Receiving Stream Name
Dratmage Basitt u
Unnamed trib. to Smith Creek
, Dramag stn --'
apt
Receiving Stream Class
C-SW
Drainage Basin Area
181,210 sf
Existing Impervious * Area
94,360 sf
Proposed Impervious * Area
58,238 sf
% Impervious* Area (total)
84.2 %
Im�iery pus *Surcax,„
D' naS66AWss zz
On -site Buildings
8,092 sf
On -site Streets'
0
On -site Parking
49,781 sf
On -site Sidewalks
365 sf
Other on -site existing
94,360 sf
Off -site
0
Total:
E=144,141 sf
E=
*Impervious area is defined as the built upon area including, but not limited to, buildings, roads, parking
areas sidewalks, gravel areas, etc.
Form SWU-101 Version 3.99 Page 2 of 4

Maintenance activities shall be performed as follows:
1. After every significant runoff producing rainfall event and at least monthly:
a. Inspect the wet detention system for sediment accumulation, erosion, trash accumulation,
vegetated cover, and general condition.
b. Check and clear the orifice of any obstructions such that drawdown of the temporary pool occurs
within 2 to 5 days as designed.
2. Repair eroded areas immediately, re -seed as necessary to maintain good vegetative cover, mow vegetative
cover to maintain a maximum height of six inches, and remove trash as needed.
3. Inspect and repair the collection system (i.e. catch basins, piping, swales, riprap, etc.) quarterly to
maintain proper functioning.
4. Remove accumulated sediment from the wet detention basin system semi-annually or when depth is
reduced to 75% of the original design depth (see diagram below). Removed sediment shall be disposed
of in an appropriate manner and shall not be handled in a manner that will adversely impact water quality
(i.e. stockpiling near a wet detention basin or stream, etc.).
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.
4, 875
When the permanent pool depth reads -i.625 feet in the main pond, the sediment shall be removed.
2.25
When the permanent pool depth reads -0 35 feet in the forebay, the sediment shall be removed.
T,
�lev2f��� �,✓,�FFefe�ce
m 4L_ l�1 plc,
BASIN DIAGRAM
ill to the blanks)
Permanent Pool Elevation 35.0
Sediment Removal Elevation 30.125 75%
Bottom Elevation
MAIN POND
5. Remove cattails and other indigenous wetland plants when they cover 50% of the basin surface. These
plants shall be encouraged to grow along the vegetated shelf and forebay berm.
6. If the basin must be drained for an emergency or to perform maintenance, the flushing of sediment
through the emergency drain shall be minimized to the maximum extent possible.
Form SWU-102 Rev 3.99
Page 3 of 4

TRIPP ENGINEERING, P.C.
0 419 Chestnut Street
Wilmington, North Carolina 28401
Phone: [phone] • FAX: [phone]
O\P%
July 27, 1999
NCDENR
Division of Environmental Management
Water Quality Section
127 Cardinal Drive
Wilmington, NC 28405-3845
Attn: Ms. Linda Lewis
Re: Jerry Porter
New Hanover County, NC
TE 99059
Dear Linda:
LECEIVEJUL�2 7 1999
:�
Enclosed please find two (2) sets of plans, one (1) signed original and one (1)
copy of the application form with narrative, one (1) wet detention supplement, two (2)
sets of signed sealed calculations and one check for the application fee.
Please review for approval and contact us with any questions or comments.
Thank you.
Sincerely,
Trim) Engineering, P.C.
Phillip G. Tripp, P.E.
PGT:dcb
Enc.