SW8050547_Historical File_20111026

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NCDEE R
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Beverly Eaves Perdue Coleen H. Sullins Dee Freeman
Governor Director Secretary
October 26, 2011
Mr. Jon W. Rosborough, Airport Director
New Hanover County Airport Authority
1740 Airport Boulevard
Wilmington, NC 28405
Subject: Stormwater Permit No. SW8 050547 Mod.
Wilmington International Airport Phases I, II, and III
High Density Dry Detention Basin Project
New Hanover County
Dear Mr. Rosborough:
The Wilmington Regional Office received a complete, modified Stormwater Management Permit
Application for Wilmington International Airport Phases I, II and III on October 21, 2011. Staff review of
the plans and specifications has determined that the project, as proposed, will comply with the
Stormwater Regulations set forth in Title 15A NCAC 2H.1000. We are forwarding modified Permit No.
SW8 050547 dated October 26, 2011, for the construction of the subject project.
This permit is for the treatment of stormwater runoff within a designated pocket of high density
consisting of 321.35 acres in accordance with Permit No. SW8 040836, the Airport Master Stormwater
Plan. This permit modification adds Phase III to the drainage area, which consists of 57.35 acres and
1,479,341 square feet of built -upon. The permit shall be effective from the date of issuance until June
15, 2015, and shall be subject to the conditions and limitations as specified therein. Please pay special
attention to the Operation and Maintenance requirements in this permit. Failure to establish an adequate
system for operation and maintenance of the stormwater management system will result in future
compliance problems.
If any parts, requirements, or limitations contained in this permit are unacceptable, you have the right to
request an adjudicatory hearing by filing a written petition with the Office of Administrative Hearings
(OAH). The written petition must conform to Chapter 150B of the North Carolina General Statutes, and
must be filed with the OAH within thirty (30) days of receipt of this permit. You should contact the OAH
with all questions regarding the filing fee (if a filing fee is required) and/or the details of the filing process
at 6714 Mail Service Center, Raleigh, NC 27699-6714, or via telephone at 919-431-3000, or visit their
website at www.ncoah.com. Unless such demands are made this permit shall be final and binding.
If you have any questions, or need additional information concerning this matter, please contact Linda
Lewis at [phone].
Sin r,rely,
Coleen H. Sullins, Director
Division of Water Quality
GDS/arl: S:IWQSIStormwater\Permits & Projects120051050547 HD12011 10 permit 050547
cc: Tim Clinkscales, P.E., Paramounte Engineering
New Hanover County Building Inspections
City of Wilmington Public Services
Beth Wetherill, New Hanover County Engineering
Wilmington Regional Office Stormwater File
Wilmington Regional Office
127 Cardinal Drive Extension, Wilmington, North Carolina 28405 One
Phone: [phone] FAX: [phone] Customer Service:1-877-623-6748 N fffiCarohna
Internet: www.ncwaterquality.org a'��1er� /�I'
An Eaual Ooonomity 1 Affirmative Action Emolnver � �/ m ` /✓�

State Stormwater Management Systems
Permit No. SW8 050547Mod.
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES
DIVISION OF WATER QUALITY
STATE STORMWATER MANAGEMENT PERMIT
HIGH DENSITY DEVELOPMENT
In accordance with the provisions of Article 21 of Chapter 143, General Statutes of
North Carolina as amended, and other applicable Laws, Rules, and Regulations
PERMISSION IS HEREBY GRANTED TO
Jon W. Rosborough and New Hanover County Airport Authority
Wilmington International Airport Phases 1, 11 and 111
1740 Airport Boulevard, Wilmington, New Hanover County
FOR THE
construction, operation and maintenance of an extended dry detention basin in
compliance with the provisions of Session Law 2008-211 and 15A NCAC 2H .1000
(hereafter collectively referred to as the "stormwater rules') and the approved
stormwater management plans and specifications and other supporting data as
attached and on file with and approved by the Division of Water Quality and considered
a part of this permit.
This permit shall be effective from the date of issuance until June 15, 2015, and shall
be subject to the following specified conditions and limitations:
I. DESIGN STANDARDS
1. This permit is effective only with respect to the nature and volume of stormwater
described in the application and other supporting data.
2. This stormwater system has been approved for the management of stormwater
runoff as described in Section 1.6 on page 3 of this permit. The stormwater
control has been designed to handle the runoff from 9,947,405 square feet of
impervious area.
3. The tract will be limited to the amount of built -upon area indicated in Section 1.6
of this permit, and per the application, the approved plans, calculations and other
supporting documentation.
4. Where an individual project is being leased or sold, the stormwater collection
system must be located in either dedicated common areas or easements and the
final plats will be recorded showing all such required easements.
5. The runoff from all built -upon area within the permitted drainage area of this
project must be directed into the permitted stormwater control system. FAA
requirements prohibit standing water (i.e., permanent pools) and stipulate that
the design story„ must be fully drained within 48 hou s. The approved plans
include a low flow device but do not include a permanent pool at the low flow
outlet or sediment storage below the low flow outlet.
Page 2 of 8

State Stormwater Management System's
Permit No. SW8 050547Mod..
6. The following design criteria have been provided in the extended dry detention
basin and must be maintained at design condition:
a. Drainage Area, acres: 321.35
Phase I onsite, ft2: 6,534,000 (150 acres)
Phase II onsite, ft2: 4,965,840 (114 acres)
Phase III onsite, ft2: 2,498,166 (57.35 acres)
Offsite, ft2' 0
b. Total Impervious Surfaces, ft2 9,947,405
Phase I: 4,247,100
Phase II: 4,220,964
Phase III: 1,479,341
C. Design Storm, inches:
Phase I: 1.0"
Phase II: 1.5"
Phase III: 1.5"
d. Basin Bottom Elevation, feet: 7.0
e.OTSS removal efficiency: 50%
f. Storage Elevation, FMSL: 13.3
g. Storage Surface Area, ft2: 602,325
h. Permitted Detention Volume, ft3: 1,274,829
i. Seasonal High Water Table, FMSL: 6.0
j. Controlling Orifice: 12.0"0 hole in 16" DIP endcap
k. Drawdown Time for 12.0"0 orifice, days: 2.65
I. Receiving Stream/River Basin: Smith Creek / Cape Fear
M. Stream Index Number: 18-74-63
n. Classification of Water Body: "C; Sw"
OTributary projects must provide an additional BMP with a sufficient TSS removal efficiency
such that the total TSS removal, including the dry detention, is at least 85%.
II. SCHEDULE OF COMPLIANCE
1. The stormwater management system shall be constructed in its entirety,
vegetated and operational for its intended use prior to the construction of any
built -upon surface.
2. During construction, erosion shall be kept to a minimum and any eroded areas of
the system will be repaired immediately.
3. The permittee shall at all times provide the operation and maintenance
necessary to assure the permitted stormwater system functions at optimum
efficiency. The approved Operation and Maintenance Plan must be followed in
its entirety and maintenance must occur at the scheduled intervals including, but
not limited to:
a. Semiannual scheduled inspections (every 6 months).
b. Sediment removal.
C. Mowing and revegetation of slopes and the vegetated filter.
d. Immediate repair of eroded areas.
e. Maintenance of all slopes in accordance with approved plans and
specifications.
f. Debris removal and unclogging of outlet structure, orifice device, flow
spreader, catch basins and piping.
g. Access to the outlet structure must be available at all times.
4. Records of maintenance activities must be kept and made available upon
request to authorized personnel of DWQ. The records will indicate the date,
activity, name of person performing the work and what actions were taken.
Page 3 of 8

State Stormwater Management Systems
Permit No. SW8 050547Mod.
5. The facilities shall be constructed as shown on the approved plans. This permit
shall become voidable unless the facilities are constructed in accordance with
the conditions of this permit, the approved plans and specifications, and other
supporting data.
6. Upon completion of construction, prior to issuance of a Certificate of Occupancy,
and prior to operation of this permitted facility, a certification must be received
from an appropriate designer for the system installed certifying that the permitted
facility has been installed in accordance with this permit, the approved plans and
specifications, and other supporting documentation. Any deviations -from the
approved plans and specifications must be noted on the Certification. A
modification may be required for those deviations.
7. If the stormwater system was used as an Erosion Control device, it must be
restored to design condition prior to operation as a stormwater treatment device,
and prior to occupancy of the facility.
8. Access to the stormwater facilities shall be maintained via appropriate
easements (as required) at all times.
9. The permittee shall submit to the Director and shall have received approval for
revised plans, specifications, and calculations prior to construction, for any
modification to the approved plans, including, but not limited to, those listed
below:
a. Any revision to any item shown on the approved plans, including the
stormwater management measures, built -upon area, details, etc.
b. Redesign or addition to the approved amount of built -upon area or to the
drainage area.
C. Further subdivision, acquisition, lease or sale of all or part of the project
area. The project area is defined as all property owned by the permittee,
for which Sedimentation and Erosion Control Plan approval or a CAMA
Major permit was sought or required.
d. Construction of any future built -upon area within the drainage area.
e. Filling in, altering, or piping of any vegetative conveyance shown on the
approved plan.
11. A copy of the approved plans and specifications shall be maintained on file by
the Permittee for a minimum of ten years from the date of the completion of
construction.
12. The Director may notify the permittee when the permitted site does not meet one
or more of the minimum requirements of the permit. Within the time frame
specified in the notice, the permittee shall submit a written time schedule to the
Director for modifying the site to meet minimum requirements. The permittee
shall provide copies of revised plans and certification in writing to the Director
that the changes have been made.
III. GENERAL CONDITIONS
1. This permit is not transferable except after notice to and approval by the Director.
At least 60 days prior to a change of ownership, or a name change of the owner
or of the project, or a mailing address change, the permittee must submit a
completed and signed Name/Ownership Change Form to the Division of Water
Quality, accompanied by the documentation listed on the form. The approval of
this request will be considered on its merits and may or may not be approved.
The permittee is responsible for compliance with all permit conditions until such
time as the Division approves the transfer request.
Page 4 of 8

State Stormwater Management System's
Permit No. SW8 050547Mod.:�
2. Failure to abide by the conditions and limitations contained in this permit may
subject the Permittee to enforcement action by the Division of Water Quality, in
accordance with North Carolina General Statute 143-215.6A to 143-215.6C.
3. The issuance of this permit does not preclude the Permittee from complying with
any and all statutes, rules, regulations, or ordinances, which may be imposed by
other government agencies (local, state, and federal) having jurisdiction.
4. In the event that the facilities fail to perform satisfactorily, including the creation
of nuisance conditions, the Permittee shall take immediate corrective action,
including those as may be required by this Division, such as the construction of
additional or replacement stormwater management systems.
5. The permittee grants DENR Staff permission to enter the property during normal
business hours for the purpose of inspecting all components of the permitted
stormwater management facility.
6. The permit may be modified, .revoked and reissued or terminated for cause. The
filing of a request for a permit modification, revocation and reissuance or
termination does not stay any permit condition.
7. Unless specified elsewhere, permanent seeding requirements for the stormwater
control must follow the guidelines established in the North Carolina Erosion and
Sediment Control Planning and Design Manual.
8. Approved plans and specifications for this project are incorporated by reference
and are enforceable parts of the permit.
9. The permittee shall submit a permit renewal application and fee at least 180
days prior to the expiration date of this permit.
Permit modified and reissued this the 26th day of October 2011
NORTH CAROLINA ENVIRONMENTAL MANAGEMENT COMMISSION
�c
Division of Wa#er Quality
By Authority of the Environmental Management Commission
Page 5 of 8

State Stormwater Management Systems
Permit No. SW8 050547Mod.
Wilmington International Airport Phases I, II and III
Stormwater Permit No. SW8 050547Mod
New Hanover Countv
Designer's Certification
1, , as a duly registered in the
State of North Carolina, having been authorized to observe (periodically/ weekly/ full
time) the construction of the project,
(Project)
for (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.
The checklist of items on page 2 of this form is included in the Certification.
Noted deviations from approved plans and specification:
Signature
Registration Number
Date
SEAL
Page 6 of 8

State Stormwater Management Systems
Permit No. SW8 050547Mod.►
Certification Requirements:
The drainage area to the system contains approximately the permitted
acreage.
2. The drainage area to the system contains no more than the permitted
amount of built -upon area.
3. All the built -upon area associated with the project is graded such that the
runoff drains to the system.
4. All roof drains are located such that the runoff is directed into the system.
5. The outlet/bypass structure elevations are per the approved plan.
6. The outlet structure is located per the approved plans.
7. Trash rack is provided on the outlet/bypass structure.
8. All slopes are grassed with permanent vegetation.
9. Vegetated slopes are no steeper than 3:1.
10. The inlets are located per the approved plans and do not cause short-
circuiting of the system.
11. The permitted amounts of surface area and/or volume have been
provided.
12. Required drawdown devices are correctly sized per the approved plans.
13. All required design depths are provided.
14. All required parts of the system are provided, such as an outlet structure
and a forebay.
15. The required system dimensions are provided per the approved plans.
cc: NCDENR-DWQ Regional Office
New Hanover County Building Inspections
Page 7 of 8

State Stormwater Management Systems
Permit No. SW8 050547Mod.
The master permit tables for Phase I and II were added to the permit on September 20,
2010, as part of the review for the modification to SW8 060515. Phase Ill was added on
October 26, 2011.
Master Permit No. SW8 050547 Phase I
Starting New BUA balance = 4 247,100-1 222,553 = 3,024 547
Offsite Permit No.
Date Issued
Offsite Project Name
Proposed
BUA
Remaining
BUA
SW8 050801
General Aviation Apron
Expansion
151,589
2,872,958
SW8 060326
Air Wilmington FBO
Building
196,725
2,676,233
SW8 060515
Credit Card Parking Lot
225,722
2,450,511
Master Permit No. SW8 050547 Phase II
Starting New BUA balance = 4 220 964-418 705 = 3,802,259
Offsite Permit No.
Date Issued
Offsite Project Name
Proposed
BUA
Remaining
BUA
SW8 050547
10/28/2009
ILM Phase I and Phase II
for gravel roads
15,843
3,786,416
Master Permit No. SW8 050547 Phase III
Starting New BUA balance = 1,479,314
Offsite Permit No.
Date Issued
Offsite Project Name
Proposed
BUA
Remaining
BUA
Page 8 of 8

ONLY
11 Date Received A Fee Paid I Permit Number 11
Applicable Rules: ❑ Coastal SW —1995 ❑ C astal SW — 2008 ❑ Ph II - Post Construction
(select all that apply) ❑ Non -Coastal SW- HQW/ORW Waters ❑ Universal Stormwater Management Plan
❑ Other WQ Mgmt Plan:
State of North Carolina
Department of Environment and Natural Resources
Division of Water Quality
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
This form may be photocopied for use as an original
I. GENERAL INFORMATION
1. Project Name (subdivision, facility, or establishment name - should be consistent with project name on plans,
specifications, letters, operation and maintenance agreements, etc.):
Wilmington International Airport Stormwater Management - Phase III
2. Location of Project (street address):
1740 Airport Boulevard
City:Wilmington County:New Hanover Zip:28405
3. Directions to project (from nearest major intersection):
South of the intersection of Gardner Drive and Airport Blvd at the Wilmington International Airport
4. Latitude:34° 15' 50" N Longitude:77° 54' 51" W of the main entrance to the project.
II. PERMIT INFORMATION:
1. a. Specify whether project is (check one): ❑New ®Modification
b.If this application is being submitted as the result of a modification to an existing permit, list the existing
permit numberSW8 050547 , its issue date (if known)Oct 28, 2009 and the status of
construction: ❑Not Started []Partially Completed* ® Completed* *provide a designer's certification
2. Specify the type of project (check one):
❑Low Density ®High Density ❑Drains to an Offsite Stormwater System ❑Other
3. If this application is being submitted as the result of a previously returned application or a letter from DWQ
requesting a state stormwater management permit application, list the stormwater project number, if
assigned, and the previous name of the project, if different than currently
proposed,
4. a. Additional Project Requirements (check applicable blanks; information on required state permits can be
obtained by contacting the Customer Service Center at 1-877-623-6748):
❑CAMA Major ®Sedimentation/Erosion Control: 6 ac of Disturbed Area
❑NPDES Industrial Stormwater ❑404/401 Permit: Proposed Impacts
b.If any of these permits have already beer,. acquired please provide the Project Name, Project/Permit Number,
issue date and the type of each permit:
Form SWU-101 Version 07Jun2010 Page 1 of 6
RECEIVED
OCT 1 0 2011
BY:

III. CONTACT INFORMATION
1. a. Print Applicant / Signing Official's name and title (specifically the developer, property owner, lessee,
designated government official, individual, etc. who owns the project):
Applicant/Organization:New Hanover County Airport Authority
Signing Official & Title:Tulie Wilsey, Deputy Director
b. Contact information for person listed in item 1a above:
Street Address:1740 Airport Boulevard
City:Wilmington State:NC Zip:28405
Mailing Address (if applicable):
City: State: Zip:
Phone: (910 ) 341-4333 Fax: (910 ) 341-3465
Emai • � � S � '� t I IYY1 P i'.OYYI
c. Please check the appropriate box. The app cant listed above is:
® The property owner (Skip to Contact Information, item 3a)
❑ Lessee* (Attach a copy of the lease agreement and complete Contact Information, item 2a and 2b below)
❑ Purchaser* (Attach a copy of the pending sales agreement and complete Contact Information, item 2a and
2b below)
❑ Developer* (Complete Contact Information, item 2a and 2b below.)
2. a. Print Property Owner's name and title below, if you are the lessee, purchaser or developer. (This is the
person who owns the property that the project is located on):
Property Owner/Organization:
Signing Official & Title:
b. Contact information for person listed in item 2a above:
Street Address:
City: State: Zip:
Mailing Address (if applicable):
City:_
Phone:
Email:
State: Zip:
Fax: ( 1
3. a. (Optional) Print the name and title of another contact such as the project's construction supervisor or other
person who can answer questions about the project:
Other Contact Person/Organization:
Signing Official & Title:
b. Contact information for person listed in item 3a above:
Mailing Address:
City:
Phone: ( )
Email:
State: Zip:
Fax: ( )
4. Local jurisdiction for building permits: New Hanover Court
Point of Contact:Tav Graham Phone #: (910 ) 798-7175
F! JVED
� uCi to 2011
Form 5WU-101 Version 07Jun2010 Page 2 of 6

IV. PROJECT INFORMATION
1. In the space provided below, bri9fly summarize how the stormwater runoff will be treated.
The extended dry basin will used to treat stormwater.
2. a. If claiming vested rights, identify the supporting documents provided and the date they were approved:
❑ Approval of a Site Specific Development Plan or PUDApproval Date:
❑ Valid Building Permit Issued Date:
❑ Other: Date:
b.If claiming vested rights, identify the regulation(s) the project has been designed in accordance with:
® Coastal SW —1995 ❑ Ph II — Post Construction
3. Stormwater runoff from this project drains to the Cape Fear River basin.
4. Total Property Area: 1620.8 acres 5. Total Coastal Wetlands Area: acres
6. Total Surface Water Area: acres
7. Total P�perty Area (4) — Total Coastal Wetlands Area (5) — Total Surface Water Area (6) = Total Project Area':
11 . �� acres
' Total project area shall be calculated to exclude the following: the normal pool of impounded structures, the area
between the banks of streams and rivers, the area below the Normal High Water (NHW) line or Mean High Water
(MHW) line, and coastal wetlands landward from the NHW (or MHW) line. The resultant project area is used to
calculate overall percent built upon area (B ). Non -coastal wetlands landward of the NHW (or MHW) line may be
included in the total project area.
8. Project percent of impervious area: (Total Impervious Area / Total Project Area) X 100 = 71 %
9. How many drainage areas does the project have?1 (For high density, count 1 for each proposed engineered
stormwater BMP. For low density and other projects, use 1 for the whole property area)
10. Complete the following information for each drainage area identified in Project Information item 9. If there
are more than four drainage areas in the project, attach an additional sheet with the information for each area
provided in the same format as below.
Basin Information
Pramage Area I
Drainage Area
Drama a Area ,
Drama ,e Area
Receiving Stream Name
Smith Creek
T
Stream Class *
C,Sw
Stream Index Number *
18-74-63
Total Drainage Area (sf)
13,998,165
On -site Drainage Area (sf)
13,998,165
Off -site Drainage Area (sf)
0
Proposed Im ervious Area** (sf)
9,947,405
% Impervious Area** (total)
71%
Iin exuaous�*-Sixrface Area...
Drama : e Area 1
Drama a Area _,
Drama . e Area ,T,
Drains Area
On -site Buildings/Lots (sf)
n/a
On -site Streets (sf)
n/a
On -site Parking (sf)
n/a
On -site Sidewalks (sf)
n/a
Other on -site (sf)
15,843
Future (sf)
8,290,304
Off -site (sf)
n/a
Existing BUA*** (sf)
1,641,258
Total (sf):
9,947,405
Stream crass and index Number can be determined at: http://portal.ncdenr.org/webl 1 s/csu/classifications
** Impervious area is defined as the built upon area including, but not limited to, buildings, roads, parking areas,
sidewalks, gravel areas, etc.
*** Report only that amount of existing BUA that will remain after development. Do not report a��tg D
to be removed and which will be replaced by new B UTA.
Form SWU-101 Version 07Jun2010 Page 3 of 6 OCT 1 0 2011

11. How was the off -site impervious area listed above determined? Provide documentation. Tributary area is
entirely on -site
Proiects in Union County: Contact DWQ Central Office staff to check if the project is located within a Threatened &
Endangered Species watershed that may be subject to more stringent stormwater requirements as per NCAC 02B .0600.
V. SUPPLEMENT AND O&M FORMS
The applicable state stormwater management permit supplement and operation and maintenance (O&M) forms
must be submitted for each BMP specified for this project. The latest versions of the forms can be downloaded
fromhtW://12ortal.ncdenr.org/web/wq./ws/su/bmp-manual.
VI. SUBMITTAL REQUIREMENTS
Only complete application packages will be accepted and reviewed by the Division of Water Quality (DWQ).
A complete package includes all of the items listed below. A detailed application instruction sheet and BMP
checklists are available from http://12ortal.ncdenr.org/web/wg/ws/su/statesw/forms does. The complete
application package should be submitted to the appropriate DWQ Office. (The appropriate office may be
found by locating project on the interactive online map at htip://12ortal.ncdenr.org/web/wq/ws/su/maps.)
Please indicate that the following required information have been provided by initialing in the space provided
for each item. All original documents MUST be signed and initialed in blue ink. Download the latest versions
for each submitted application package from htW://12ortal.ncdenr.org/web/wq/ws/su/statesw/forms does.
�n ttals, e
1. Original and one copy of the Stormwater Management Permit Application Form. �4(�! /
2. Original and one copy of the signed and notarized Deed Restrictions & Protective Covenants C
Form. (if required as per Part VII below)
3. Original of the applicable Supplement Form(s) (sealed, signed and dated) and O&M
agreement(s) for each BMP. AMV
4. Permit application processing fee of $ yable to NCDENR. (For an Express review, refer to
hU://www.envhelD.org/12ages/onestopexpress.html for information on the Express program
and the associated fees. Contact the appropriate regional office Express Permit Coordinator for
additional information and to schedule the required application meeting.)
5. A detailed narrative (one to two pages) describing the stormwater treatment/management for
the project. This is required in addition to the brief summary provided in the Project
Information, item 1.
6. A USGS map identifying the site location. If the receiving stream is reported as class SA or the
receiving stream drains to class SA waters within lh mile of the site boundary, include the 1h
mile radius on the map.
7. Sealed, signed and dated calculations.
Two sets of plans folded to 8.5" x 14" (sealed, signed, & dated), including:
a. Development/Project name.
b. Engineer and firm.
c. Location map with named streets and NCSR numbers.
d. Legend.
e. North arrow.
f. Scale.
g. Revision number and dates.
h. Identify all surface waters on the plans by delineating the normal pool elevation of
impounded structures, the banks of streams and rivers, the MHW or NHW line of tidal
waters, and any coastal wetlands landward of the MHW or NHW lines.
• Delineate the vegetated buffer landward from the normal pool elevation of impounded
structures, the banks of streams or rivers, and the MHW (or NHW) of tidal waters.
i. Dimensioned property/project boundary with bearings & distances.
j. Site Layout with all BUA identified and dimensioned.
k. Existing contours, proposed contours, spot elevations, finished floor elevations.
1. Details of roads, drainage features, collection systems, and stormwater control measures.
m. Wetlands delineated, or a note on the plans that none exist. (Must be delineated by a
qualified person. Provide documentation of qualifications and identify the person who
made the determination on the plans.
n. Existing drainage (including off -site), drainage easements, pipe sizes, runoff calculations.
o. Drainage areas delineated (included in the main set of plans, not as a separate documnt �D p. Vegetated buffers (where required). ! -
Form S WU-101 Version 07Jun2010 Page 4 of 6 { 0 6 T 1 U Lull

9. dopy of any applicable soils report with the associated SHWT elevations (Please identify S '
elevations in addition to depths) as well as a map of the boring locations with the existing 4
A copy of the most current property deed. Deed book see attached Page No:
For corporations and lim-ited Liability corporations (LLC): Provide documentation from the NC
Secretary of State or other official documentation, which supports the titles and positions held
by the persons listed in Contact Information, item 1a, 2a, and/or 3a per NCAC 2H.1003(e). The
corporation or LLC must be listed as an active corporation in good standing with the NC
Secretary of State, otherwise the application will be returned.
htft2://www.secretary.state.nc.us/Corl2orations/CSearr-h.asgx
VII. DEED RESTRICTIONS AND PROTECTIVE COVENANTS
elevations and boring logs. Include an 8.5"x11" copy of the NRCS County Soils map with the
project area clearly delineated. For projects with infiltration BMPs, the report should also
include the soil type, expected infiltration rate, and the method of determining the infiltration rate.
(Infiltration Devices submitted to WiRO: Schedule a site visit for DWQ to verify the SHWT prior
to submittal, [phone].),7—
cl-
For all subdivisions, outparcels, and future development, the appropriate property restrictions and protective
covenants are required to be recorded prior to the sale of any lot. If lot sizes vary significantly or the proposed
BUA allocations vary, a table listing each lot number, lot size, and the allowable built -upon area must be provided
as an attachment to the completed and notarized deed restriction form. The appropriate deed restrictions and
protective covenants forms can be downloaded from
b=://12ortal.ncdenr.org/web/wQ/ws/su/statesw/forms docs. Download the latest versions for each submittal.
In the instances where the applicant is different than the property owner, it is the responsibility of the property
owner to sign the deed restrictions and protective covenants form while the applicant is responsible for ensuring
that the deed restrictions are recorded.
By the notarized signature(s) below, the permit holder(s) certify that the recorded property restrictions and
protective covenants for this project, if required, shall include all the items required in the permit and listed
on the forms available on the website, that the covenants will be binding on all parties and persons claiming
under them, that they will run with the land, that the required covenants cannot be changed or deleted
without concurrence from the NC DWQ, and that they will be recorded prior to the sale of any lot.
VIII. CONSULTANT INFORMATION AND AUTHORIZATION
Applicant: Complete this section if you wish to designate authority to another individual and/or firm (such as a
consulting engineer and/or firm) so that they may provide information on your behalf for this project (such as
addressing requests for additional information).
Consulting Engineer:Tim Clinkscales
Consulting Firm: Paramounte Engineering
Mailing Address:5911 Oleander Drive
City: Wilmington
Phone: (910 ) 791-6707
Email:
State:NC Zip:28403
Fax: (910 ) 791-6760
IX. PROPERTY OWNER AUTHORIZATION (if Contact Information, item 2 has been filled out, complete this
section)
I, (print or type name of person listed in Contact Information, item 2a) . certify that I
own the property identified in this permit application, and thus give permission to (print or type name of person
listed in Contact Information, item 1a) with (print or type name of organization listed in
Contact Information, item 1a) to develop the project as currently proposed. A copy of
the lease agreement or pending property sales contract has been provided with the submittal, which indicates the
party responsible for the operation and maintenance of the stormwater system.
EI�TED
OCT 1 0 2011
Form SWU-101 Version 07Jun2010Y
Page 5 of 6 ,__.._.

As the legal property owner I acknowledge, understand, and agree by my signature below, that if my designated
agent (entity listed in Contact Information, item 1) dissolves their company and/or cancels or defaults on their
lease agreement, or pending sale, responsibility for compliance with the DWQ Stormwater permit reverts back to
me, the property owner. As the property owner, it is my responsibility to notify DWQ immediately and submit a
completed Name/Ownership Change Form within 30 days; otherwise I will be operating a stormwater treatment
facility without a valid permit. I understand that the operation of a stormwater treatment facility without a valid
permit is a violation of NC General Statue 143-215.1 and may result in appropriate enforcement action including
the assessment of civil penalties of up to $25,000 per day, pursuant to NCGS 143-215.6.
Signature: Date:
a Notary Public for the State of County of
do hereby certify that
before me this _ day of
personally appeared
. and acknowledge the due execution of the application for a
stormwater permit. Witness my hand and official seal,
SEAL
My commission expires
X. APPLICANT'S CERTIFICATION
I. (print or type name of person listed in Contact Information, item 1a) Tulie Wilsey
certify that the information included on this permit application form is, to the best of my knowledge, correct and
that the project will be constructed in conformance with the approved plans, that the required deed restrictions
and protective covenants will be recorded, and that the proposed project complies with the requirements of the
applicable wT
rule under 15A NCAC 2H .1000, SL 2006-246 (Ph. II - Post Construction) or SL 2008-211.
Signature: � W�-Iklt
gn Date:
I, 5mDRA 5 . K6urky a Notary Public for the State of NokM l.l: &14AfA County of
do hereby certify that Jy4ja A • W r eS!y personally appeared
before me this day of beT66E2 aO 11 and apknowledge ution of the application for a
Stormwater permit. Witness my hand and official seal, � � �-- �/ - 7ec
w'
Illgllll
O� S. RO
A
NOTARY _
PUBLIC
S
S�fiICK G�
SEAL
My commission expires b IAA .9 0 / (o
P�ECEIVIED
OCT 1 0 2011
Form SWU-101 Version 077un2010 Page 6 of 6

Permit Number: SXti I?D1! 5 DST
(to be provided by D Q)
Drainage Area Number:
Dry Extended 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 dry extended detention basin system is defined as the dry detention basin, outlet
structure, pretreatment including forebays and the vegetated filter if one is provided.
This system (check one):
E does ❑ does not incorporate a vegetated filter at the outlet.
This system (check one):
❑ does ® does not incorporate pretreatment other than a forebay.
Important maintenance procedures:
- The drainage area will be managed to reduce the sediment load to the dry
extended detention basin.
- Immediately after the dry extended detention basin is established, the vegetation
will be watered twice weekly if needed until the plants become established
(commonly six weeks).
- No portion of the dry extended detention pond will be fertilized after the first
initial fertilization that is required to establish the vegetation.
- I will maintain the vegetation in and around the basin at a height of
approximately six inches.
- Once a year, a dam safety expert will inspect the embankment.
After the dry extended detention basin is established, it will be inspected once a quarter
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 will be kept in a known set
location and will be available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element:
Potentialproblem:
How I will remediate the roblem:
The entire BMP
Trash/debris is present.
Remove the trash/debris.
The perimeter of the dry
Areas of bare soil and/or
Regrade the soil if necessary to
extended detention
erosive gullies have formed.
remove the gully, and then plant a
basin
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Form SW401-Dry Detention O&M-Rev.3
RECEIVED
OCT 1 0 2011
BY•
Page 1 of 4

BMP element:
Potentialproblem:
How I will remediate theproblem:
The inlet device: pipe or
Swale
The pipe is clogged (if
ap licable).
Unclog the pipe. Dispose of the
sediment off -site.
The pipe is cracked or
Replace the pipe.
otherwise damaged (if
applicable).
Erosion is occurring in the
Swale (if applicable).
Regrade the Swale if necessary to
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
Search for the source of the
and reduced the depth to 75%
sediment and remedy the problem if
of the original design depth
possible. Remove the sediment and
(see diagram below).
dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Erosion has occurred or
Provide additional erosion
riprap is displaced.
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 pesticides are used, wipe
them on the plants rather than
spraying.
The main treatment area
Sediment has accumulated
Search for the source of the
and reduced the depth to 75%
sediment and remedy the problem if
of the original design depth
possible. Remove the sediment and
(see diagram below).
dispose of it in a location where it
will not cause impacts to streams or
the BMP. Revegetate disturbed
areas immediately with sod
(preferred) or seed protected with
securely staked erosion mat.
Water is standing more than
5 days after a storm event.
Check outlet structure for clogging.
If it is a design issue, consult an
appropriate rofessional.
Weeds and noxious plants are
Remove the plants by hand or by
growing in the main
wiping them with pesticide (do not
treatment area.
.t"a.IT-11ET V ED
OCT 1 0 2011
Form SW401-Dry Detention O&M-Rev.3-_- Page 2 of 4

BMP element:
Potentialproblem:
How I will remediate the probleM
The embankment
Shrubs or trees have started
Remove shrubs or trees
to grow on the embankment.
immediately.
Crass cover is unhealthy or
Resiore the health of the grass cover
eroding.
— consult a professional if necessary.
Signs of seepage on the
Consult a professional.
downstream face.
Evidence of muskrat or
Use traps to remove muskrats and
beaver activity is present.
consult a professional to remove
beavers.
An annual inspection by an
Make all needed repairs.
appropriate professional
shows that the embankment
needs repair.
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 NC Division of Water
damage have occurred at the
Quality 401 Oversight Unit at 919-
outlet.
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 acczumulated sediments.
When the basin depth readsM,1 P
Wfeet in the main pond, the sediment shall be removed.
When the basin depth reads Z. ! feet in the forebay, the sediment shall be removed.
Sediment Removal
Bottom
BASIN DIAGRAM
(fill in the blanks)
Temporary Pool Elevation 13.30
11.00 Te or Pool
-------------- -- olume Sediment Removal Elevation�b Q,rj j
it8.25 25% -------------------------------------------
Sediment Bottom Elevation 7.00
Storage
FOREBAY MAIN POND
Form SW401-Dry Detention O&M-Rev.3
RECEIVED
OCT 1 o 2011
BY:
Page 3 of 4
Volume
------A
25%

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:Wilmington International Airport Stormwater Management - Phase III
BMP drainage area number:l
Print name:Julie Wilsey
Title:Denuty Director
Address:1740 Airport Boulevard, Wilmington NC 28405
Phone: (9 1 OYB41-4333 _
Signature: � U !Y/
Date: V lot 5&(f
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.
1, �S"DkA S . P-OWt14 , a Notary Public for the State of
f Vol2Tl+ C V-OL►N A , County of &2wyscJt e k- , do hereby certify that
TALI F, A • WaAeq personally appeared before me this 511-
day of ( zc7zm iL , a-o// , and acknowledge the due execution of the
forgoing dry detention basin maintenance requirements. Witness my hand and official
seal,
6gyp, S. /?0�
a
d ►VOTARY S
pUBLIC 2
�SWICKG�•,
SEAL
My commission expires Oro / a 9Lao/6
-:CEIVTED
I
Form SW401-Dry Detention O&M-Rev.3 OCT 1 0 2011
BY:
Page 4 of 4

Permit No.
(to be provided by DWQ)
Tom:
STORMWATER MANAGEMENT PERMIT APPLICATION FORM a r
NCDENR
401 CERTIFICATION APPLICATION FORM
DRY EXTENDED 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 the required information.
I. PRWECT INFORMATION
Project name Wilmington International Airport Stormwater Management - Phase III
Contact person Tim Clinksca►es
Phone number 910 791-6707
Date 9/30/2011
Drainage area number
U. DEMN INFORMAPON
Site Characteristics
Drainage area
Impervious area
% Impervious
Design rainfall depth
Peak Flow Calculations
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 control
Storage Volume: Non -SA Waters
Minimum required volume
Provided volume
Sediment storage volume provided
Storage Volume: SA Waters
1.5" runoff volume
Pre -development 1-yr, 24-hr runoff volume
Post -development 1-yr, 24-hr runoff volume
Minimum required volume
Provided volume
Sediment storage volume provided
Basin Design Parameters
Drawdown time
SHWT elevation
Basin bottom elevation
Storage elevation
Basin side slopes
Top elevation
Freeboard provided
Basin Bottom Dimensions
Basin length
Basin width
Length to width ratio
13,998,165.00 fe
9,947,405.00 fe
0.71
1.27 in
3.83
in
7200.
(unitless)
88.00
(unitless)
0.76
in/hr
7500
ft3/sec
173.00
fe/sec
98.00
ft3/sec
1,033,693.00 ft3
1,274,829:00 ft3
241,135.00 ft3
n/a ft3
nla ft3
n/a ft3
#VALUE! ft3
n/a ft3
n/a ft3
265 days
6.00 fmsl
7.00 fmsl
�644r%43J4 fmsl
10 4.0 :1
2000.fmsl
6.70 ft
2.12500 It
450.00 ft
4.00 :1
OK
Increase to at least 25% of volume provided
#VALUE!
#VALUE!
OK
Raise -basin bottom, ua ho a+ least 2-ft above SH05-
t3.3
OK
Too deep, maximum depth of 10-feet allowed
OK
7RECEI'TEI�-
OK OCT 1 0 2011
BY:
r1
eg
1
Form SW401-Dry Extended Detention Basin-Rev.3 Parts I. & II. Design Summary, Page 1 of 2

Additional Information
Total runoff volume captured by basin
Forebay provided
Is basin in a recorded drainage easement?
Does basin capture all runoff at ultimate build -out?
Is a sediment depth indicator included?
Does the basin include a drain?
407,00 ac-in Forebay is required
y (Y or N)
y (Y or N) OK
y (Y or N) OK
y (Y or N) OK
y (Y or N) OK
Permit No.
(to be provided by DWQ)
CEIVF'eD
OCT 1 0 ZU11
Form SW401-Dry Extended Detention Basin-Rev.3 Parts I. & II. Design Summary, Page 2 of 2

MEMORY TRANSMISSION REPORT
TIME :10-27-'11 09:39
FAX NO.1 :910-350-2018
NAME :DENR Wilmington
FILE NO.
129
DATE
: 10.27 09:37
TO
: 993414365
DOCUMENT PAGES
9
START TIME
10.27 09:37
END TIME
10.27 09:39
PAGES SENT
9
STATUS
OK
*** SUCCESSFUL TX NOTICE ***
state otivortb DCaaroHes
eQarttiaeat of Eavironmeaa and Natural Itssoaroes
wllmiautoa x4azi .al ama
Bcvsi{y Savas Peed+ia, Governor FAX Ca'%Y]r Y 813EET
)Pies -JYirdswn, Secretary
No. Pages ocoxcl. covarj=
Fes, 3 yr/ - y3G s Fmc: [phone]
12y c—ai.. I nri— sxa-to.., 140 20405 a (910> 796-72I9 a .-La Mcj—1 <>V, c —ity urn,-,.. L— A-u... jamyj_,

State of forth Carolina
(Department of Environment and Natural Resources
Wilmington Regional Office
Beverly Eaves Perdue, Governor FAX COVER SHEET
Date
To:
Co:
Fax:
Re:
A11-11117 -74 '01('O!�?
's � L
Dee Freeman, Secretary
No. Pages (excl. cover):
From: Jo Casmer
Phone: [phone]
Fax: [phone]
Oor 7 4-
a- ,r,00p- ,
127 Cardinal Drive Extension Wilmington, NC 28405 o [phone] o An Equal Opportunity Affirmative Action Employer

MEMORY TRANSMISSION REPORT
TIME :10-26-'11 14:56
FAX NO.1 :910-350-2004
NAME :DENR Wilmington
FILE NO.
480
DATE
10.26 14:54
TO
B 97916760
DOCUMENT PAGES
9
START TIME
: 10.26 14:54
END TIME
: 10.26 14:56
PAGES SENT
9
STATUS
OK
*** SUCCESSFUL TX NOTICE ***
State or North Carolian
Dapartaneot or Havlroumeot and Natural Reaoor
Wtlmtn�too Rasbaal Oflfa+e
Bevmty J1!o�•ss Aeid�ra Governor $.A1X COVER S8L*+=T
pee lrr�errma, Secretary
:
To: ��/ i'�s'� _ _ C� li•iT �r�' c .� �� S Fro7o2_ J'o Caemer
Phone: [9101 796-7336
F'sx: � ��'� � ►�+ d Fax: i9l01.350-,7AU4
127 Cardinal Drive Extension. Wilmingt—, NC 28403 o [phone] a An Equal C3 pa unity Aktr r.ati­q tipn $enpluyar

State of North Carolina
Department of Environment and Natural Resources
Wilmington Regional ®face
Beverly Eaves Perdue, Governor FAX COVER SHEET DeeFreeman, Secretary
Date: l 1� No. Pages (excl. cover):
To: �/r °�? eG"ems e- x�AP S From: Jo Casmer
Co: l" �� �dy r� �n Phone: [phone]
Fax: �lP �� d Fax: [phone]
127 Cardinal Drive Extension, Wilmington, NC 28405 ® [phone] a An Equal Opportunity Affirmative Action Employer

PARAMOUNT
.
E t,
N G I N E E F2 I N G, I N CO
99911 OLEANDER DRIVE, SUITE 201 CT
W I L M I N G T O N, N C 2 8 4 0 3
9 1 0 - 7 9 1 - 6 7 0 7 (0) 9 1 0 - 7 9 1 - 6 7 6 0 (F)
1�
L E T T E R n F T R A N 9 M T T 'r A T.
To:
NCDENR-Land Quality Section
Date
1 10/2012011
127 Cardinal Drive Extension
Wilmington, NC 28405
Re:
Wilmington International Airport — Phase III
Express Review Submittal
Attn:
Janet Russell/Linda Lewis
Pro'ect No.
I 11181.PE
e are sendine Originals
he following iterns:1 Correspondence
® Prints ❑ Shop Drawings ❑ Calculations
® Plans ❑ Specifications ® Other as listed below
Quantity
Date
Dwg. No.
Description
2
Plans (Final Design — Not Released For Construction)
Issue Status: ® For Approval ❑ As Requested ❑ Construction ❑ Bid
❑ For Your Use ❑ For Review and Comment ❑ Approved as Noted ❑ See Remarks
[Action Taken ❑ No Exceptions Taken ❑ Make Corrections Noted ❑ Amend & Resubmit
❑ Rejected - See Remarks ❑ Approved as Submitted ❑ Other
emarks:
m Clinkscales, PE PLS
�EED
OCT 2 1 2011
BY:-J�%�

Lewis,Linda
From:
Lewis,Linda
Sent:
Thursday, October 20, 2011 11:17 AM
To:
'tclinkscales'
Cc:
'Julie Wilsey'
Subject:
RE: SW8 050547
Tim:
Thank you for pointing that out. I was aware that the surface areas listed for the dry pond proposed condition
represents the previously permitted "as -built" surface areas plus the proposed expanded basin surface areas.
But, as you suggest, I compared the wrong numbers because when I list them out next to each other (see
below) it's not what 1 thought it was on Tuesday.
This table represents a compilation of 2009 proposed area, the as -built area and the 2011 proposed area
(forebay plus the main pond). The first number is the 2009 proposed area; the second number is the "as -built"
condition which is your existing condition; and the third number represents the 2011 "proposed" condition:
2009
As -built
2011
net change
7
250
215
185
-30
8
13657
4960
4960
0
9
21965
21865
12695
-9170
10
94443
93150
91790
-1360
11
263058
M 130
259240
-1890
12
411821
410570
419580
+9010
13
506082
Jii5455
588660
+83,205
14
539055
539140
634210
+95,070
I'm not sure I understand how the as -built existing area at elevations 7, 9, and 10 has decreased because you
are not doing anything at those elevations. It would make sense to me that the net change from as -built to
proposed 2011 for those areas would be zero.
Beginning at elevation 11, if the existing "as -built" area is 261130 sf, and you are extending the 11 contour up
into the expanded basin area in the low flow channel by 250 feet, and it's 10 feet wide, then it would make
sense that the surface area at elevation 11 should go up by 2500 square feet, but instead it goes down by
1890 sf.
At elevation 12, 1 am scaling a total added area of about 14,000 sf, but the proposed area only goes up by
9,010 sf.
At elevations 13 and 14, as expected, the biggest jumps in area occur.
I'm OK with the calculations because they propose smaller areas than I come up with, resulting in smaller
volumes. There's nothing that needs to be labeled.
The other issue of the dimensions still needs to be addressed.
Linda Lewis
NC Division of Water Quality
127 Cardinal Drive Ext.
Wilmington, NC 28405
910-796-7215

E-mair correspondence to and from this address may be subject to the North Carolina Public Records Law and may
be disclosed to third parties.
From: tclinkscales [mailto:[e-mail]]
Sent: Wednesday, October 19, 2011 11:39 AM
To: Lewis,Linda
Cc: cmiilis
Subject: RE: SW8 050547
Linda,
Here is the response for question #1. Please let us know if this answers your question.
In regard to comment #1...1 believe there might be a small misunderstanding ... the "Proposed Dry Basin (Including
Existing Basin)' stage storage calculations are not solely indicating the elevations/areas for the expanded basin but
reflect elevations/areas for the entire expanded basin (existing as -built basin plus the proposed phase III expanded
basin). This spreadsheet reflects what the surface area will be at each elevation once the basin is completely
constructed (existing plus expanded basin). As a result, in response to the comment regarding at what elevations there
should be expansions and that it should not occur to elevation 11 in the lower half and elevation 12 in the upper half
and such ... please note that the information given is just not the expanded basin, but cumulative information for the
entire basin. Please find that the cumulative areas at each elevation have been carefully calculated using the as -built of
the existing basin in combination with the proposed expanded basin; therefore the "Proposed Dry Basin" stage storage
spreadsheet will reflect the completed basin once the proposed phase III expansion is performed. This is why the
information starts at elevation 7 for the total basin and elevation 9 for the forebay. I hope that this expounded
information regarding the stage/storage calculations will put us all on the same page.
For the contouring, is their a certain contour that needs labeling.
Have a good day
Tim
Tim Clinkscales PE, PLS
DARAMOUNTE
PARAMOUNTE ENGINEERING, INC
5911 Oleander Drive, Suite 201
Wilmington, NC 28403
OFFICE: [phone]
CELL: [phone]
FAX: [phone]
From: Lewis,Linda [maiito:[e-mail]]
Sent: Tuesday, October 18, 2011 3:22 PM
To: tciinkscales
Cc: Russell, Janet; Julie Wilsey
Subject: SW8 050547
I am reviewing the submittal today and have the following questions:

1: The bottom elevation for the expanded basin area is 12 in the upper half and 11 in the lower half. But,
the areas in the stage -storage table start increasing much earlier - at elevation 9 (+3595 so, elevation
10 (+9850 so, elevation 11 (+65010 so and elevation 12 (+150210 so. At elevation 13 and above, we
should see the largest jumps but we don't. These are very large amounts of added surface area that do
not appear to be supported by the proposed grading plan at these elevations. Where are you adding
surface area at elevations 9 and 10? Based on the proposed contours, the most that the surface area
at elevation 11 would expand by is the length of the low -flow channel above the existing 11 contour in
the lower half of the basin, to the connecting culvert (250 feet) times its width of 10 feet, which is 2500
sf. At elevation 12, the surface area would expand by 10800 in the lower half plus 390 linear feet of low -
flow channel times a width of 8 feet in the upper half, or approximately a total of 14,000 square feet. I
just don't see where these large increases in surface area you are proposing are coming from.
2. The dimensions for the expansion are provided at unknown points along the contour. Please provide a
dimension for each straight line and a radius for each curved line, beginning and ending at known
points.
3. The O&M document indicates that a vegetated filter has been provided at the outlet. I don't think this is
true although the O&M for the 2009 permit contains the same misinformation. I believe that the
requirement is for each proposed project to provide a suitable "pre-treatment" device, such that the total
TSS removal is 85%, which negates the need for a VFS at the outlet. The current approved plans do
not show any such VFS. I'm going to simply mark through the "DOES" box and mark the "DOES NOT"
box on the O&M.
Please resubmit the requested items by October 25, 2011.
Linda Lewis
NC Division of Water Quality
127 Cardinal Drive Ext.
Wilmington, NC 28405
910-796-7215
E-mail correspondence to and from this address may be subject to the North Carolina Public Records Law and may
be disclosed to third parties.

r
PARAMOUNTE
E N G I N E E R I N G, I N C.
9 9 9 1 1 OLEANDER DRIVE, SUITE 2 0 1
W I L M I N G T O N, N C 2 8 4 0 3
9 1 0- 7 9 1- 6 7 0 7( O) 9 1 0- 7 9 1- 6 7 6 0 ( F)
L E T T F R n R 'r R A N C n r T r •r A T
To:
NCDENR-Land Quality Section
Date
1 10/06/2011
127 Cardinal Drive Extension
Wilmington, NC 28405
Re:
Wilmington International Airport— Phase III
Express Review Submittal
Attn:
PWAI n# S
Project No.
I 11181 YE
e are sendin
® Originals
® Prints
❑ Shop Drawings
❑ Calculations
Correspondence
® Plans
❑ Specifications
® Other as listed below
he following iterns:1
Quantity
Date
Dwg. No.
Description
2
Plans (Final Design — Not Released For Construction)
1
Stormwater Narrative w/ Calculations
1
Wetland J.D.
1
Check for Express Review Fee ($2000.00)
2
Storrnwater Permit Application Form (Original & Copy)
1
Dry Detention Basin Supplement (Original)
1
Dry Detention Basin O&M Agreement (Original)
1
Financial Responsibility Form (Erosion Control Application)
1
Erosion Control Fee ($390)
ssue Status: ® For Approval ❑ As Requested ❑ Construction ❑ Bid
❑ For Your Use ❑ For Review and Comment ❑ Approved as Noted ❑ See Remarks
ction Taken: ❑ No Exceptions Taken ❑ Make Corrections Noted ❑ Amend & Resubmit
❑ Rejected - See Remarks ❑ Approved as Submitted ❑ Other
Cc:
RECEIVED
OCT 102011
ccsS
By
Signed:
Tim Clinkscales, PE PLS
ME •10

U.S. ARMY CORPS OF ENGINEERS
WILMINGTON DISTRICT
Action Id. SAW-2010-01904 County: New Hanover U.S.G.S. Quad: Wilmington
NOTIFICATION OF JURISDICTIONAL DETERMINATION
Property Owner/Agent: Wilmington Airport Authority
C/o Mr. Jon Rosborough, Airport Director
Address: 1740 Airport Boulevard, Suite 12
Wilmington, North Carolina 28405
Telephone No.: [phone]
Property description:
Size (acres) 447
Nearest Waterway Smith Creek
USGS HUC 03030007
DEC 2 1 2010 s
b1 '
t`F
L
Nearest Town Wilmington
River Basin Cape Fear
Coordinates N 34.273142, W-77.916436
Location description The area being verified is the west portion of the Wilmington International Airport located along
23rd Street and Blue Clay Road, Wilmington New Hanover County North Carolina
Indicate Which of the Following Apply:
A. Preliminary Determination
Based on preliminary information, there may be wetlands on the above described property. We strongly suggest you have this
property inspected to determine the extent of Department of the Army (DA) jurisdiction. To be considered final, a jurisdictional
determination must be verified by the Corps. This preliminary determination is not an appealable action under the Regulatory
Program Administrative Appeal Process (Reference 33 CFR Part 331).
B. Approved Determination
_ There are Navigable Waters of the United States within the above described property subject to the permit requirements of
Section 10 of the Rivers and Harbors Act and Section 404 of the Clean Water Act. Unless there is a change in the law or our
published regulations, this determination may be relied upon for a period not to exceed five years from the date of this
notification.
X There are waters of the U.S. including wetlands on the above described property subject to the Dermit reauirements of
Section 404 of the Clean Water Act (CWA)(33 USC 4 1344)Unless there is a change in the law or our published
regulations, this determination may be relied upon for a period not to exceed five years from the date of this notification
We strongly suggest you have the wetlands on your property delineated. Due to the size of your property and/or our present
workload, the Corps may not be able to accomplish this wetland delineation in a timely manner. For a more timely delineation,
you may wish to obtain a consultant. To be considered final, any delineation must be verified by the Corps.
_ The waters of the U.S. including wetland on your property have been delineated and the delineation has been verified by the
Corps. We strongly suggest you have this delineation surveyed. Upon completion, this survey should be reviewed and verified
by the Corps. Once verified, this survey will provide an accurate depiction of all areas subject to CWA jurisdiction on your
property which, provided there is no change in the law or our published regulations, may be relied upon for a period not to exceed
five years.
X The waters of the U.S. including wetlands have been delineated and surveyed and are accurately depicted on the plat
siSned by the Corps Regulatory Official identified below on 12/21/2010 Unless there is a change in the law or our
Published regulations, this determination may be relied upon for a period not to exceed five years from the date of this
notification.
There are no waters of the U.S., to include wetlands, present on the above described property which are subject to the permit
requirements of Section 404 of the Clean Water Act (33 USC 1344). Unless there is a change in the law or our published
regulations, this determination may be relied upon for a period not to exceed five years from the date of
OCT 1 0 2011
Ry.

X The property is located in one of the 20 Coastal Counties subject to regulation under the Coastal Area Management Act
(CAMA). You should contact the Division of Coastal Management in Wilmington NC at [phone] to determine
their requirements.
Placement of dredged or fill material within waters of the US and/or wetlands without a Department of the Army permit may
constitute a violation of Section 301 of the Clean Water Act (33 USC § 1311). If you have any questions regarding this determination
and/or the Corps regulatory program, please contact Emily Hughes at 910-251-4635.
C. Basis For Determination
This site exhibits wetland criteria as described in the 1987 Coms Wetland Delineation Manual and is adjacent to an unnamed
tributary to Smith Creek. This site also contains a waterbody that exhibits an ordinary high water mark and is an unnamed
tributary to Smith Creek. This determination is based on information submitted by Withers and Ravenel and a site visit by
Emily Hughes on 11/10/2010.
D. Remarks
E. Appeals Information (This information applies only to approved jurisdictional determinations as indicated in B.
above)
This correspondence constitutes an approved jurisdictional determination for the above described site. If you object to this
determination, you may request an administrative appeal under Corps regulations at 33 CFR part 331. Enclosed you will find a
Notification of Appeal Process (NAP) fact sheet and request for appeal (RFA) form. if you request to appeal this determination you
must submit a completed RFA form to the following address:
District Engineer, Wilmington Regulatory Division
Attn: Emily Hughes, Project Manager,
Wilmington Regulatory Field Office
69 Darlington Ave.
Wilmington, North Carolina 28403-1398
In order for an RFA to be accepted by the Corps, the Corps must determine that it is complete, that it meets the criteria for appeal
under 33 CFR part 331.5, and that it has been received by the District Office within 60 days of the date of the NAP. Should you
decide to submit an RFA form, it must be received at the above address by 2/21/2011.
**It is not necessary to submit an RFA form to the District Office if you do not object to the determination in this correspondence.**
Corps Regulatory Official: `
Date December 21, 2010 Expiration Date December 21, 2015
Action Id. SAW-2010-01904
The Wilmington District is committed to providing the highest level of support to the public. To help us ensure we continue to do so,
please complete the Customer Satisfaction Survey located at our website at http://regulatoiy.usacesurvey.com/ to complete the survey
online.
Copy furnished:
Withers & Ravenel Attn: Troy Beasley, 1410 Commonwealth Dr., Ste 101 Wilmington NC 28403
w" �EIVE
OCT 102011

-2W ;Z1,
kTION 01P ADI VF. R
t APPEAL
Applicant: Wilmington International Airport File Number: 2010-01904 Date: 12/21/201
Attached is:
See Section below
INITIAL PROFFERED PERMIT (Standard Permit or Letter of permission)
A
PROFFERED PERMIT (Standard Permit or Letter of permission)
B
PERMIT DENIAL
C
X
APPROVED JURISDICTIONAL DETERMINATION
D
PRELIMINARY JURISDICTIONAL DETERMINATION
E
SECTION .The f61,16W'--J Id-iffstritive appeal n .9p an �d�
ep tiof the above
decision. -Additi.6nalbr
. in i"'
mation-pWil.- Eoun,
htq://www6usare,arMy.niiVfgQW/ a �e te Carp regulations ,at.33CFRPart331,.
A: INITIAL PROFFERED PERMIT: You may accept or object to the permit.
• ACCEPT: If you received a Standard Permit, you may sign the permit document and return it to the district engineer for final
authorization. If you received a Letter of Permission (LOP), you may accept the LOP and your work is authorized. Your
signature on the Standard Permit or acceptance of the LOP means that you accept the permit in its entirety, and waive all rights
to appeal the permit, including its terms and conditions, and approved jurisdictional determinations associated with the permit.
• OBJECT: If you object to the permit (Standard or LOP) because of certain terms and conditions therein, you may request that
the permit be modified accordingly. You must complete Section II of this form and return the form to the district engineer.
Your objections must be received by the district engineer within 60 days of the date of this notice, or you will forfeit your right
to appeal the permit in the future. Upon receipt of your letter, the district engineer will evaluate your objections and may: (a)
modify the permit to address all of your concerns, (b) modify the permit to address some of your objections, or (c) not modify
the permit having determined that the permit should be issued as previously written. After evaluating your objections, the
district engineer will send you a proffered permit for your reconsideration, as indicated in Section B below.
B: PROFFERED PERMIT: Youmayaccept or appeal the permit
• ACCEPT: If you received a Standard Permit, you may sign the permit document and return it to the district engineer for final
authorization. If you received a Letter of Permission (LOP), you may accept the LOP and your work is authorized. Your
signature on the Standard Permit or acceptance of the LOP means that you accept the permit in its entirety, and waive all rights
to appeal the permit, including its terms and conditions, and approved jurisdictional determinations associated with the pen -nit.
• APPEAL: If you choose to decline the proffered permit (Standard or LOP) because of certain terms and conditions therein, you
may appeal the declined permit under the Corps of Engineers Administrative Appeal Process by completing Section 11 of this
form and sending the form to the division engineer. This form must be received by the division engineer within 60 days of the
date of this notice.
C: PERMIT DENIAL: You may appeal the denial of a permit under the Corps of Engineers Administrative Appeal Process
by completing Section II of this form and sending the form to the division engineer. This form must be received by the division
engineer within 60 days of the date of this notice.
Rr-F _'TV
OCT 1 0 2011

D: APPROVED JURISDICTIONAL DETERMINATION: You may accept or appeal the approved JD or
provide new information.
• ACCEPT: You do not need to notify the Corps to accept an approved JD. Failure to notify the Corps within 60 days of the
date of this notice, means that you accept the approved JD in its entirety, and waive all rights to appeal the approved JD.
• APPEAL: If you disagree with the approved JD, you may appeal the approved JD under the Corps of Engineers Administrative
Appeal Process by completing Section II of this form and sending the form to the division engineer. This form must be received
by the division engineer within 60 days of the date of this notice.
E: PRELIMINARY JURISDICTIONAL DETERMINATION: You do not need to respond to the Corps
regarding the preliminary JD. The Preliminary JD is not appealable. If you wish, you may request an
approved JD (which may be appealed), by contacting the Corps district for further instruction. Also you may
provide new information for further consideration by the Corps to reevaluate the JD.
SECTION II REQUEST FOR APPA
or.:OBJC TIOI�IS'OAN`I1�TI I'IAL PROFFERED- PERMIT
REASONS FOR APPEAL OR OBJECTIONS: (Describe your reasons for appealing the decision or your objections to an
initial proffered permit in clear concise statements. You may attach additional information to this form to clarify where your reasons
or objections are addressed in the administrative record.)
ADDITIONAL INFORMATION: The appeal is limited to a review of the administrative record, the Corps memorandum for the
record of the appeal conference or meeting, and any supplemental information that the review officer has determined is needed to
clarify the administrative record. Neither the appellant nor the Corps may add new information or analyses to the record. However,
you may provide additional information to clarify the location of information that is already in the administrative record.
POINT 0F.00NTACT.F6R.QUESn-'0N
If you have questions regarding this decision and/or the appeal
If you only have questions regarding the appeal process you may
process you may contact:
also contact:
Ms. Emily Hughes
Jason Steele
Regulatory Specialist
Administrative Appeals Review Officer
69 Darlington Avenue
60 Forsyth Street, SW (Room 9M10)
Wilmington, NC 28403-1343
Atlanta, GA 30303-8801
910-251-4635
404-562-5137
RIGHT OF ENTRY: Your signature below grants the right of entry to Corps of Engineers personnel, and any government
consultants, to conduct investigations of the project site during the course of the appeal process. You will be provided a 15 day
notice of any site investigation, and will have the opportunity to participate in all site investigations.
RE Date:
Telephone number:
I V L:D
Signature of appellant or agent. OC A ?All

PHASE III STORMWATER BASIN EXPANSION
NEW HANOVER COUNTY, NORTH CAROLINA
STORMWATER / EROSION CONTROL NARRATIVE
Prepared for:
Wilmington International Airport
1740 Airport Blvd.
Wilmington, NC 28405
Prepared by:
PARAMOUNTE
E N G I N E E R 1 N G, I N C.
5911 Oleander Drive, Suite 201
Wilmington, NC 28403
Project #11181.PF
September 2011
,1osas¢7,��/
OCT 1 0 2011

PHASE III STORMWATER BASIN EXPANSION
NEW HANOVER COUNTY, NORTH CAROLINA
Project #11181.PE
Table of Contents
Design Narrative
Maintenance
Erosion and Sedimentation Control Specification
Soils Map
USGS Map
Stormwater Calculations
Pre/Post & Pond Routing Calculations (2-year / 10-year / 25-year)
Pond Routing Calculations (Emergency Spillway Only)
Rip Rap Apron Calculations
RECEIVED
OCT102011
BY:

PHASE III STORMWATER BASIN EXPANSION
NEW HANOVER COUNTY; NORTH CAROLINA
Project #11181.PE
DESIGN NARRATIVE
The Wilmington International Airport proposes to expand the existing stormwater dry detention basin
south of the Airport Blvd. to handle an additional +/- 57 acres of drainage area. The proposed phase III
stormwater drainage area currently drains to an unnamed tributary of Smith Creek (C; Sw) [18-74-63]
within the Cape Fear River Basin. According to the NRCS Soil Survey of New Hanover County the
majority of the soil across the drainage area consists of Leon sand (Le) and Seagate fine sand (Se). The
drainage area currently consists of a combination of woods, grassed area, and a small amount of existing
impervious.
The proposed phase III expanded basin drainage area will consist of future outparcel imperviousness
and a small amount of existing imperviousness from redirecting portions of Airport Blvd. into the basin.
All stormwater runoff will be conveyed to the dry detention basin as the drainage area is developed by
way of a future storm sewer system. The expanded basin has been designed to meet New Hanover
County & NCDENR requirements; which include storing the runoff from the one and a half -inch rainfall
while providing 25% additional volume for sediment storage, controlling the 2 yr., 10 yr., and 25 yr. post
development runoff to pre -development rates, and safely passing the peak discharge from the 100 year
event with sufficient freeboard.
Please note that in regard to the previously permitted phase I & II stormwater design that all provided
calculations by PEI reflect the drainage area characteristics previously performed by Talbert & Bright,
Inc. during their Phase II expansion permit to NCDENR and NHC in 2009. PEI has determined the phase
III drainage area, pre/post curve numbers, time of concentrations, etc. but reference the information
established within the previously approved drainage area calculations for phases I & II. In regard to the
dry basin itself, note that all design regarding the expanded basin has been determined from an existing
basin as -built provided by the client and not from previously proposed phase II design calculations.
Therefore the expanded dry basin calculations provided are based on a current as -built (not calculations)
and the stormwater drainage area calculations based on previously approved phase II characteristics
merged with PEI's proposed phase III drainage area information.
Due to the expanded phase III drainage area, there is a need to also expand the existing basin and modify
the temporary storage volume by raising the existing 16" riser pipe. In regard to NHC pre/post
requirements, please find that we have modeled the expanded basin and the results of the pre/post
stormwater modeling conclude that the additional volume provided by expanding the basin is sufficient
to meet all NHC requirements without modifying the existing outlet structure network. Note that the
expanded phase III dry detention basin has been designed to maintain continuity with the existing basin
design while providing additional storage volume for the phase III drainage area.
In regard to sedimentation and erosion control, please find the need for a construction entrance, silt
fence, and rip rap aprons for the basin expansion. Please see sheet C-1.0 for all Erosion Control and
Sequence of Construction notes. The sedimentation and erosion control design will commence as
RECEIVED►
OCT I 0 2011
BY:

depicted in the construction sequence. Please find all reference material and stormwater / erosion control
calculations in the following pages of this report. Note that some calculations have also been located on
the plans for easy reference during construction. Silt fence is being used as the primary erosion measure
even though above the suggested disturbed area because the pond will contain a large portion of the
sediment during the construction. In addition, based on staff comments, double silt fence will be placed
along areas that adjoin the wetlands.
Upon construction of the Phase III basin, the dirt generated will be placed on Airport Authority property
at the intersection of Gardner Drive and Airport Blvd. The property in question will be used for the
proposed Veterans Administration Outpatient Clinic and is in the process of obtaining a land disturbance
from New Hanover County because it is a lease property. Because of the concurrent construction
sequence for both projects, the necessary construction entrances will be in place on Airport Blvd as
shown on our proposed plan and Gardner Drive for the proposed VA facility.
MAINTENANCE
Contractors shall be responsible for periodic inspection and maintenance of all indicated erosion control
devices in accordance with the plans and specifications. In addition, inspection and any necessary
maintenance will be required immediately following any significant storm event. Any erosion control
measure that fails to function as intended shall be repaired immediately. Upon completion of
construction and the establishment of stabilized ground cover, the property owner shall be responsible
for any on going site maintenance.
EROSION AND SEDIMENTATION CONTROL SPECIFICATION
PART1-GENERAL
1.1 RELATED DOCUMENT
A. Drawings and general provisions of the Contract, including General and Supplementary
Conditions and Division 1 Specification Sections, apply to this Section.
1.2 WORK INCLUDED
A. Contractor shall take every reasonable precaution throughout construction to prevent the
erosion of soil and the sedimentation of streams, lakes, reservoirs, other water impoundments,
ground surfaces, or other property as required by State and Local regulations.
B. Contractor shall, upon suspension or completion of land -disturbing activities, provide
protection covering for disturbed areas. Permanent vegetation shall be established at the
earliest practicable time. Temporary and permanent erosion control measures shall be
coordinated to assure economical, effective, and continuous erosion and sediment control
throughout the construction and post construction period.
1.3 RELATED SECTIONS
A. Related Sections - The following Sections contain requirements that relate to this Section:
1. 01011 - Existing Underground Utilities RECEIVED
OCT 1 0 Z011
BY:

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RECEIVED
OCT 1 0 2011
BY:
W
77" 55' 25'
77' 54'49"

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M..m

Project Name: PH.III Detention Expansion
Client: ILM
Project Number: 11181.PE
Prepared By: TGC
Date: 1015/11
PA TEA MOUNTE
Basin: PHASE III AREA [PRE] Drainage area= 57.35 acres = 0.090 miz
D
Land Use
% of Basin
CN A
CN B
CN C
CN D
Wet hted CN
Wooded - Good
26.0
30
55
70
77
17,16
Existing Impervious
2.5
98
98
98
98
2.45
Open Space - Fair
71.5
49
69
79
84
54.70
Sum:
100.0
Sum:. 7431
Curve numbers taken from:
TR-55
Use: 75
values input by user
values calculated by spreadsheet
Er'EIVED
OCT 1 0 2011
:3Y:

Project Name: PH.III Detention Expansion "--"A"
Client: ILM 1 A .�1`'3► M O U N T
Project Number: 11181.PE
Prepared By: TGC
Date: 10/5/11
Basin: PHASE III AREA [PRE] Drainage area= 57.35 acres = 0.090 mil
Time of Concentration
Overland Flow
Hydraulic Length =
3,100 ft.
Slope =
0.25 %
Ground Cover =
Unpaved
TR-55 Tc Worksheet Results
64 min.
FINED
i
OCT 1 0 Nil
..1

Project Name: PH.III Detention Expansion R 1"1 M O � UT N TE
Client: ILM
Project Number: 11181.13E
Prepared By: TGC
Date: 10/5/11
Basin: PHASE III AREA [POST] Drainage area= 57.35 acres = 0.090 m12
Area Calculations
Land Use Area (Ac.) % of Basin
Out parcel Imprv. (65%) 30.74
Existing Roadway Imprv. 3.22
TotalImpv: 33.96 59.2
Open Space - Good 23.39 40.8
Sum: 57.35 100
. F,CEIVED
OCT 102011

Project Name: PH.III Detention Expansion
Client: ILM
Project Number: 11181.PE
Prepared By: TGC
Date: 10/5/11
F.-RAMOUNTE
N < 1 N 1- 1 I N .
Basin: PHASE III AREA [POST] Drainage area= 57.35 acres = 0.090 mil
Curve Number
HSG:
A
B
C
D
Sum
% of Basin
0.0
50.0
0.0
50.0
100.0
Land Use % of Basin
CN A
CN B
CN C
CN D
Weighted CN
Impervious 59.2
98
98
98
98
58.03
Open Space - Good 40.8
36
60
73
79
28.34
Sum: 1000
Sum:: 8638
Curve numbers taken from:
TR-55
Use:
RECE D
OCT 102011
BY:

Project Name: PH.III Detention Expansion � T�T
Client: ILM PA RA M O V j� T i
Project Number: 11181.PE
Prepared By: TGC
Date: 10/5/11
Basin: PHASE III AREA [POST] Drainage area= 57.35 acres = 0.090 miz
Time of Concentration
Piped Flow
Hydraulic Length =
2,350 ft.
Slope =
0.005 ft/ft
n =
0.013 RCP
D=
2ft.
V =
0.97 fps
T =
40.4 min.
TC =
40 min.
RFICEIVEID
OCT 1 0 2011
BI':

Project Name: PH.III Detention Expansion a RA M O U N TE
Client: ILM .11�
Project Number: 11181.PE
Prepared By: TGC
Date: 10/5/11
State Stormwater Information (Mod. SW8050547)
Phase I (Per SW8050547 Mod.)
Drainage Area =
6,534,000 sf
Impervious =
4,247,100 sf
% Impervious =
65.00 %
Design Rainfall Depth =
1.00 in
Volume Req. =
345,758 cf
Min. Req. Sed. Storage =
20 %
Req. Sed. Storage Volume =
69,152 cf
Min. Req. Volume w/ Sed. Storage =
414,910 cf
Phase II (Per SW8050547 Mod.)
Drainage Area =
4,965,840 sf
Impervious =
4,220,964 sf
% Impervious =
85.00 %
Design Rainfall Depth =
1.50 in
Volume Req. =
505,895 cf
Min. Req. Sed. Storage =
25 %
Req. Sed. Storage Volume =
126,474 cf
Min. Req. Volume w/ Sed. Storage =
632,369 cf
Phase III (Proposed Phase for Permit Mod.)
Drainage Area =
2,498,325 sf
Impervious =
1,479,341 sf
% Impervious =
59.21 %
Design Rainfall Depth =
1.50 in
Runoff Coefficient, Rv =
0.583
Volume Req. =
182,040 cf
Min. Req. Sed. Storage =
25 %
Req. Sed. Storage Volume =
45,510 cf
Min. Req. Volume w/ Sed. Storage =
227,550 cf
Total Basin Information
Drainage Area =
13,998,165 sf
Impervious =
9,947,405 sf
% Impervious =
71.06 %
Volume Req. =
1,033,693 cf
Req. Sed. Storage Volume =
241,135 cf
El. @ Sed. Storage Volume =
10.96 el.
Min. Req. Volume w/ Sed. Storage =
1,274,829 cf
Design Rainfall Depth (Weighted) =
1.27 in
Req. Forebay Volume =
254,966 cf
Provided Forebay Volume =
20.67 %
Temporary Storage Elevation =
13.30 el.
Provided Storage Elevation =
43310$I.
Provided Storage Volume =
1,397,405 cf
Drawdown Time =
2.65 day!
0(d e i" N&Ve I. Sk
13"3
RECENED
OCT 1 0 ZOtt
BY:

Project Name: PH.III Detention Expansion
Client: ILM
Project Number: 11181.PE
Prepared By: TGC
Date: 10/5/11
Existing Basin (per As -Built)
Forebay
PIA RA M OUN TE
El.
Surface Area (sf)
Incr. Volume (cf)
Cuml. Volume (cf)
8.25
0
0
0
9.00
3,755
1,408
1,408
10.00
11,210
7,483
8,891
11.00
66,900
39,055
47,946
12.00
141,200
104,050
151,996
12.50
170,900
78,025
230,021
Main Basin
El.
Surface Area (sf)
Incr. Volume (cf)
Cuml. Volume (cf)
7.00
215
0
0
8.00
4,960
2,588
2,588
9.00
18,110
11,535
14,123
10.00
81,940
50,025
64,148
11.00
194,230
138,085
202,233
12.00
269,370
231,800
434,033
13.00
505,455
387,413
821,445
14.00
539,140
522,298
1,343,743
15.00
555,160
547,150
1,890,893
16.00
572,045
563,603
2,454,495
17.00
586,300
579,173
3,033,668
18.00
600,690
593,495
3,627,163
19.00
615,275
607,983
4,235,145
20.00
630,870
623,073
4,858,218
Total Basin
El.
Surface Area (sf)
Incr. Volume (cf)
Cuml. Volume (cf)
7.00
215
0
0
8.00
4,960
2,588
2,588
9.00
21,865
13,413
1G,000
10.00
93,150
57,508
73,508
11.00
261,130
177,140
250,648
12.00
410,570
335,850
586,498
13.00
505,455
458,013
1,044,510
14.00
539,140
522,298
1,566,808
15.00
555,160
547,150
2,113,958
16.00
572,045
563,603
2,677,560
17.00
586,300
579,173
3,256,733
18.00
600,690
593,495
3,850,228
19.00
615,275
607,983
4,458,210
20.00
630,870
623,073
5,081,283
Temporary Storage Volume =
1,047,278
cf
Temporary Storage Elevation =
13.01
el.
i RECEIVEI"
OCT 1 0 2011
y:

Projed Name: PH.III Detention Expansion � f
Client: ILM PA RA M O �.J N
Project Number: 11181.PE
Prepared By: TGC
Date: 10/5/11
Proposed Dry Basin (Including Existing Basin)
Forebav
El.
Surface Area (sf)
Incr. Volume (cf)
Cuml. Volume c
9.00
1,735
0
0
10.00
5,215
3,475
3,475
11.00
39,980
22,598
26,073
12.00
105,430
72,705
98,778
13.00
223,960 1164,695
1 263,473
Total Basin (Including Forebay)
El.
Surface Area (sf)
Incr. Volume (cf)
Cum . Volume (cf)
7.00
185
0
0
8.00
4,960
2,573
2,573
9.00
21,695
13,328
15,900
10.00
91,790
56,743
72,643
11.00
259,240
175,515
248,158
12.00
419,580
339,410
587,568
13.00
588,660
504,120
1,091,688
14.00
634,210
611,435
1,703,123
15.00
656,285
645,248
2 348 370
16.00
679,290
667,788
3 016 158
17.00
699,795
689,543
3 705 700
18.00
720,505
710 150
4,415 850
19.00
741,555
731 030
5 146 880
20.00
763,365
752,460
5 899,340
Temporary Storage Volume =
1,274 829
cf
Temporary Storage Elevation =
LL30J
eel.
Forebay Calculations:
Req. Forebay Vol. (20% of Temp. Vol.)
= 254,966
cf
Provided Forebay Volume =
263,473
cf
Provided Forebay Volume =
20.67
Drawdown Calculations:
Dia. of Proposed Low -flow Orifice =
12.00
in.
Elevation of Low -flow Orifice =
7,Mel.
Water Surface (next outlet) =
3.50
el.
Driving Head (Storage Depth) =
6.50
el.
Average Elevation Head
2.17
el.
Cd (Coefficient of Discharge) =
0.60
Q (flowrate through orifice) =
5.57
cfs
Drawdown Time =
2.65
days
7OCTn
EIVED
10201

Project Name: PH.III Detention Expansion
Client: ILM
Project Number: 11181.PE
Prepared By: TGC
Date: 10/5/11
Pre Development Input
Phase I & II (Per Previous ILM Design)
Basin ID: DA#1 (Sub 15)
Drainage Area 17.6 Ac.
CN 62
Tc 61 min
Basin ID: DA#2 (Sub 16)
Drainage Area 16.3 Ac.
CN 59
Tc 50 min
Basin ID: DA#3 (Sub 18)
Drainage Area 30.9 Ac.
CN 79
Tc 22 min
Basin ID: DA#4 (Sub 19A)
Drainage Area 6.9 Ac.
CN 64
Tc 55 min
Phase III (Proposed Expansion)
Basin ID: DA#5
Drainage Area 57.35 Ac.
CN 75
Tc 64 min
FA RA M OUNTE
} N • I N I t i �. 1 N t I N .
�.�FCEIVEI.�
OCT 102011
i

Project Name: PH.III Detention Expansion
Client: ILM
Project Number: 11181.1PE
Prepared By: TGC
Date: 10/5/11
Post Development Input
Phase I & II (Per Previous ILM Design)
Basin ID: PH. I & PH. II
Drainage Area 264 Ac.
CN 88
Tc 180 min
Basin ID: Bypass Area
Drainage Area 21.6 Ac.
CN 87
Tc 22 min
Phase III (Proposed Expansion)
Basin ID: PH. III
Drainage Area 57.35 Ac.
CN 87
Tc 40 min
PA RA pit o U TE
I N 1- - 1 F tt 1 " 1 .N .
ECEIVED
I OCT 1 0 2011
IBY:

Hydrograph Summary RePP ft Hydrographs Extension for AutoCAD® Civil 3D® 2009 by Autodesk, Inc. v6.066
Hyd.
No.
Hydrograph
type
(origin)
Peak
flow
(cfs)
Time
interval
(min)
Time to
peak
(min)
Hyd.
volume
(cult)
Inflow
hyd(s)
Maximum
elevation
(ft)
Total
strge used
(cuft)
Hydrograph
description
1
SCS Runoff
75.16
1
892
1,582,993
-----
----
---
TOTAL DA: PRE
2
SCS Runoff
173.09
1
855
3,021,207
-----
----
------
TOTAL DA: POST
RE rMD
i OCT 1 0 2011
l
BY:
ILM-Basin Phase III Expansion - STATE 1
VRBW r Period: 1 Year TZdn�esdayOct
5, 2011

Channel Report
Hydraflow Express Extension for AutoCADO Civil 3D® 2009 byAutodesk, Inc. Wednesday, Oct 5 2011
LOW FLOW CHANNEL: 1 YR
User -defined
Highlighted
Invert Elev (ft) = 10.00
Depth (ft)
= 2.54
Slope (%) = 0.02
Q (cfs)
= 173.00
N-Value = 0.030
Area (sqft)
= 235.65
Velocity (ft/s)
= 0.73
Calculations
Wetted Perim (ft)
= 216.71
Compute by: Known Q
Crit Depth, Yc (ft)
= 1.59
Known Q (cfs) = 173.00
Top Width (ft)
= 216.32
EGL (ft)
= 2.55
(Sta, El, n)-(Sta, El, n)...
(0.00, 13.00)-(4.00, 12.00, 0.030)-(104.00, 11.00, 0.030)-(108.00, 10.00, 0.030)-(112.00, 10.00, 0.030)-(116.00, 11.00, 0.030)-(216.00, 12.00, 0.030)
-(220.00, 13.00, 0.030)
Elev (ft)
14.00
13.00
12.00
11.00
10.00
Section
0 50 100 150 200
Sta (ft)
Depth (ft)
4.00
3.00
2.00
1.00
ME
-1.00
250
OCT 1 ® 2011
BY:

RECEIVED
OCT 1 0 2011
BY:

V. :;".
RECEIVED
OCT 1 0 2011
BY

ATA
NCDENR
�� Z
o
SC_0pe__-'
For DENR Us• ONLY,
North Carolina Department of Environment and ReNewec
Natural Resources $ems: _LQ_7� O
Request for Express Permit Review nme: — in 99
►aLL-IN all the infl nrtadon below and CHECK the Permil(s) you are requesting for express
Coordinator along, adtil a completed DETAILED narratim of clan iPDF Niel and likinity i
of the project location. Please include tide form In the appllcaflon package
• Asheville Ragion-A/lson Davidson 828-296.4698;alison davidson�nncmafLnet
• Fayetteville or Raleigh Region -David Lee 919-791-4203, di vial lea tncmall nat
• Mooresville & -Patrick Grogan 704.663-3772 or oatrkkmoaanOmmali net
• Washington Regbn-Lyn Hardison 252-946-9215 orhm frerdison&bncmagnet
• Wilmington Region-JJenet Russell910-350-2004 orheatmssell�ncmalLnet
NOTE., Project application received after 12 noon will be stamped in Die following work day.
Conflor: review FAXor Email the eted form to Exl
Project Name: WILMINGTON INTERNATIONAL AIRPORT PHASE Ili__-CDunt(. NEW HANQVER _
Applicant: JULIE WILSEY Company: n NEW HANOVER COUNTY AIRPORT AUTHORITY
Address: 1740 AIRPORT BLVDCihr: WILMINGTON. State: _K Zip: 28405-
Phone:[phone] Fax:; - Email:[e-mail]
Physical Location:WILMINGTON INTERNATIONAL AIRPORT
Project Drains into SMITH CREEK waters -Water classification (forclassiftatansee-http://h2o.enr.state.nc.usbimslmports/reoonsWB.htmi
Project Located in CAPE FEAR River Basin. Is project draining to class ORW waters? N , within'% mile and draining to class SA waters N or within 1 mile
and draining to class HQW waters? N
-- Field Code Changed 1
Engineer/Consultant: TIM CLINKSCALES. PE. PLS Company:PARAMOUNTE ENGINEEBING. INC ---- — - Field Cade Changes
---------------------------------------
Address: 5911 OLEANADER DRIVE City: WILMINGTON. State: NC Zip 28403-_ - --
Phone:[phone] Fax::[phone] Email: [e-mail]-- ____________________ ____•- FieidCode Changed SECTION ONE: REQUESTING A SCOPING MEETING ONLY -- — —
❑ Scoping Meeling ONLY ❑ DWQ, ❑ DCM, -❑ DLR, ❑ OTHER: _
SECTION TWO: CHECK ONLY THE PROGRAM IS) YOU ARE REQUESTING CHECK ONLY THE PROGRAM iS) YOU ARE REQUESTING FOR�P EXPRESS PERMITTING PERMITTING
❑ 401 Unit ❑ Stream Origin Determination: _ # of stream calls - Please attach TOPO map marking the areas in questions
❑ Intermittent/Perennial Determination: _ # of stream calls - Please attach TOPO map marking the areas in questions
❑ 401 Water Quality Certification ❑ Isolated Welland (_linear it or —acres)
❑ Riparian Buffer Authorization ❑ Minor Variance ❑ Major General Variance
® State Storm aster ❑ General ❑ SFR,
❑Bkhd & Bt Rmp, ❑ Clear & Grub, ❑ Utility
❑ Low Density ❑ Low Density -Curb & Gutter _#
Curb Outlet Swales ❑ Off -site [SW _ (Provide permit#)]
® High Density -Detention Pond j#Treatment Systems
❑ High Density -Infiltration _#TieatmentSystem
❑ High Density -Bio-Retention _ # Treatment Systems
❑ High Dens"ornwater Wetlands _ # Treatment Systems❑ High Density -
Other _# Treatment Systems /❑ MODIFICATION: ❑ Major ❑ Minor ❑ Revision SW _(Provide pemit#)
Fill
❑ Coastal Management ® BTp
Rarfs&Cyhp rts ® �trbudt roves Imo anon
n�
anitlQn
U Iantl ueve o ment
a a ve o ment ran at
® Land Quality ® Eroslon and Sedimentation Control Plan with 5 acres to be disturbed.(CK # (for DENR use))
SECTION THREE - PLEASE CHECK ALL THAT IS APPLICABLE TO YOUR PROJECT (for both scoping and express meeting request)
Wetlands on Site ® Yes ❑ No
Buffer Impacts: ® No ❑ YES: _acre(s)
Wetlands Delineation has been completed: ® Yes ❑ No
Isolated wetland on Property ❑ Yes ® No
US ACOE Approval of Delineation completed: ® Yes ❑ No
404 Application in Process w/ US ACOE: ❑ Yes ® No Permit
Received from US ACOE R Yes LJ No
Fee Split for multiple penuft Check#
For DENR use only
ToWFeeAmount $
SUBMITTALDATES
Fee
SUBMITTAL DATES
Fee
CARA
$
Variance ( Maj; ❑ Min)
$ Ed
SW ([1110, i] LD, ❑ Gen)
$
401:
$
LQS
$
Stream Dater_
$
'7 ED
SEP9 211
NCDENR EXPRESS September 2008 U
O Ue-e- IA 1 0y. C LC) V A18 a-r-I t 5 C 4. 5\ nN3
k-0 0 `i o `) 3 (o , A-„ c C`'1 a sir P 1 •�-Y, .

ILM PHASE III STORMWATER EXPANSION
Express Stormwater Narrative
September 22, 2011
Project Narrative:
New Hanover County Airport Authority is proposing to the expansion of the existing basin for
the phase III portion at the Wilmington International Airport. The project will consist of sizing
the dry detention basin for the additional acreage (57 acres) for future buildout at the Airport.
The project is within a drainage basin that drains to Smith Creek (C;SW). This project will not
have any wetland impacts and all permit applications for the development will be submitted to
the necessary agency for review and approval.

Russell, Janet
From: tclinkscales [[e-mail]]
Sent: Friday, September 23, 2011 1:39 PM
To: Russell, Janet
Subject: RE: Express Submittal Meeting and Date
Here is the pdf, the existing number is SW8 050547
Thanks
Tim
Tim Clinkscales PE, PLS
JIL
ARA MOUNTS
�-
PARAMOUNTE ENGINEERING, INC
591 1 Oleander Drive, Suite 201
Wilmington, NC 28403
OFFICE: [phone]
CELL: [phone]
FAX: [phone]
From: Russell, Janetfmailto:janet.russell(@ncdenr.govl
Sent: Friday, September 23, 20119:35 AM
To: tclinkscales
Subject: RE: Express Submittal Meeting and Date
Tim, do you have a pdf site plan showing the proposed expansion? Also, will this be a modification to an existing permit
(which SW8#)?
Thanks,
Janet
From: tclinkscales[mailto:tclinkscalesCa-bparamounte-eng com]
Sent: Thursday, September 22, 2011 6:56 PM
To: Russell, Janet
Cc: Julie Wilsey
Subject: Express Submittal Meeting and Date
Janet,
We would like to request an express stormwater/erosion meeting for the expansion of the existing dry detention basin at
the airport. This will be called Phase III for the project. Enclosed is the necessary information for such meeting to take
place. Let me know of anything else that is needed and have a good night.
Tim
Tim Clinkscales PE PLS
DARAMOUNTE
r: IN
PARAMOUNTE ENGINEERING, INC
5911 Oleander Drive, Suite 201

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-•r'Y:
-
AREA (150 AC)
y
e
74 W, r FELl
P
9UILT UPON AREA
1+
PHASE I EXISTING BUA
•" 1,222,553 SF 28.07 AC
~� PHASE II EXISTING BUA
PHOTO TAKEN,I��
SUMMER 2009''' 418,705 SF 9.61 AC
TOTAL EXISTING BUA
1,641,258 SF 37.68 AC
PHASE 11 PROPOSED BUA (GRAVEL MAINTENANCE ROAD)
15,843 SF 0.36 AC
—A - - 1�1'�•: ] ice..
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%4 _ '•.1 4,PHASE If DRAINAGE f � •�C::� �'•`" •'•.• f f r f �r I •A r.
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9UILT UPDN AREA r fyr. ��''�.,•� _ s
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