SW7071105_HISTORICAL FILE_20210218

STORMWATER DIVISION CODING SHEET
POST -CONSTRUCTION PERMITS
PERMIT NO.
SW J% %
DOC TYPE
❑ CURRENT PERMIT
❑ APPROVED PLANS
F11HISTORICAL FILE
El COMPLIANCE EVALUATION INSPECTION
DOC DATE��
YYYYMMDD

ROY COOPER
Govemor
MICHAEL S. REGAN
Secretary
BRIAN WRENN
Director
NORTH CAROLINA
Environmental Quality
February 18, 2021
Currituck County
Attention: Ben Strikeleather, Manager
153 Courthouse Road
Currituck. NC 27929
Subject: Stormwater Permit Renewal
Stormwater Management Permit SW7071105
Currituck County Water Treatment Plant RO Expansion
Currituck County
Dear Mr. Strikeleather:
A Division of Energy, Mineral, and Land Resources file review has determined that
Stormwater Permit SW7071105 for a stormwater treatment system consisting of a wet
detention pond serving the Currituck County Water Treatment Plant RO expansion
located on Maple Road, Currituck, NC expires on March 5, 2022. This is a reminder that
permit renewal applications are due 180 days prior to expiration. We do not have a
record of receiving a renewal application.
Please submit a completed permit renewal application along with a $505.00 fee for
permit renewal within the required time. Permit application forms for renewal can be
found on our website at: https://deq.nc.gov/about/divisions/energy-mineral-and-land-
resources/stormwater/stormwater-program/post-construction-2. North Carolina General
Statutes and the Coastal Stormwater rules require that this property be covered under a
stormwater permit. Failure to maintain a permit subjects the owner to assessment of
civil penalties.
If you have questions, please feel free to contact me at [phone]. 1 will be glad to
discuss this by phone or meet with you. If you would like, I can e-mail you a copy of the
application forms. You can request a copy by e-mailing me at
roger.thorpe(�ncdenr.gov.
Sincerely,
Roger K. Thorpe
Environmental Engineer
North Carolina Department of Environmental Quality I Division of Energy, Mineral and Land Resources
Washington Regional Office 1 943 Washington Square Mall I Washington, North Carolina 27889
252.9466487

ARCADIS
Infrastructure, environment, buildings
TRANSMITTAL LETTER
To.
NCDENR-Division of Water Quality;
Washington Regional Office
943 Washington Square Mall
Washington, NC 27889
Phone: [phone]
DEC 0 3 2009 ARCADIS G&M of
North Carolina, Inc
801 Corporate Center Drive
Suite 300
Raleigh,
Copies North Carolina 27607-5073
DonnaVoliva— CurrituckCounty Tel [phone]
File Fax [phone]
WATER RESOURCES
From:
Dan Williams
Date
December 1. 2009
Subject ARCADIS Protect No
Currituck County Mainland Water Treatment NC706021.2000
Plant RO Expansion
We are sending you:
® Attached ❑ Under Separate Cover Via the Following Items:
❑ Shop Drawings ❑ Plans ❑ Specifications ❑ Change Order
❑ Prints ❑ Samples ❑ Copy of Letter ❑ Reports
❑ Other.
Copies
Date
Drawing No.
Rev.
Description
Action'
1
11/24/09
Stormwater Management Systems Designer's Certification for
Permit No. S W7071105
F
Action'
❑ A Approved
❑ CR Correct and Resubmit
❑
Resubmit Copies
❑ AN Approved As Noted
® F File
❑
Return_ Copies
❑ AS As Requested
❑ FA For Approval
❑
Review and Comment
❑ Other.
Mailing Method
❑ U.S. Postal Service 1" Class
❑ Courier/Hand Delivery ❑ FedEx Priority Overnight
❑ FedEx 2-Day Delivery
❑ Certified/Registered Mail
❑ United Parcel Service (UPS) ® FedEx Standard Overnight
❑ FedEx Economy
❑ Other.
Comments:
Page

DWQ/WRRO Fax:[phone] Mar 11 '08 15:52 P.07
.. .. � i-re.�.--T—ram..-� � ... � f.7='�M� • - .. • '
State Stormwater Management Systems
Permit No._SW7071105
Designer's Certification
as a duly registered �o+esYrd�o� C7r�rheP/in the State of North
Carolina, having been authorized to observe (periodically/ weekly/ full time) the construction of the project,
IP4'4Ie"4- Praril
(Project)
t&-
for rt, r4weL .d (Project Owner) hereby state that, to the best of my abilities, due
care and diligence was used in the Aservation 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 Oa99 17
Date //• 9009 _
\\\\\ A C ARO /// SEAL
`�OQ •LESS/ • 9�i
.a SEAL 9 =
. 029976 _
SI1
DEC 0 3 2009
h

DWQ/IJAR0 Fax:[phone] Mar 11 '08 15:52 P.08
State Stormwater Management Systems
Permit No. 3W7071105
Certification Requirements:
�. The drainage area to the system contains approximately the permitted acreage.
�. The drainage area to the system contains no more than the permitted amount of built -upon area.
�. 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.
hr F1'•'q q< -p
The outlet/bypass structure elevations are per the approved plan. �, „ W
The outlet structure is located per the approved plans. OEC 0 3 2009
_,�7. Trash rack is provided on the outlet/bypass structure.
All slopes are grassed with permanent vegetation.
Vegetated slopes are no steeper than 3:1.
The inlets are located per the approved plans and do not cause short-circuiting of the system.
,�1_1 . The permitted amounts of surface area and/or volume have been provided.
Required drawdown devices are correctly sized per the approved plans.
%13. All required design depths are provided.
��14. _ All required parrs of the system are provided, such as a vegetated shelf, and a forehay.
The required system dimensions are provided per the approved plans.
cc: NCDENR-DWQ , Washington Regional Office
Currituck County Building Inspections
7
.__ .... ... ...... ...�..,..F•iYi`{>"'..'-'r".�'�M-'SidCE4e't3�v.,'.'v�.ii�•i�iCb'i

to WATF90 Michael F. Easley, Govea�
�O G William G. Ross Jr., Secretary
h r North Carolina Department of Environment and Natural Resources
>_ 1
O T Coleen H. Sullins, Director
Division of Water Quality
March 5, 2008
Currituck County
Attn.: Daniel F. Scanlon
P.O. BOX 39
Currituck, NC 27929
Subject: Stormwater Review SW7071105
Mainland Water Treatment Plant RO Expansion
High Density Stormwater Permit
Currituck County
Dear Mr. Scanlon:
The Washington Regional Office received a complete Stormwater Management Permit Application for Mainland
Water Treatment Plant RO Expansion on December 4, 2007. 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 Permit No. SW7071105 dated March 5, 2008, for the construction of the subject
project.
2 � z'—
This permit shall be effective from the date of issuance until March 5r2018; 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 upon written request within thirty (30) days following receipt of this permit. This request
must be in the form of a written petition, conforming to Chapter 150E of the North Carolina General Statutes, and
filed with the Office of Administrative Hearings, 6714 Mail Service Center, Raleigh, NC 27699-6714. 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 Ernest Odei-
Larbi, or me at [phone].
ncerel
AI Hodge, Regi:of Supervisor
Surface Water Protection Section
Washington Regional Office
AH/eol: J:\WPDATA\WQS\ State SW-EOL\Permits — Hybrid -HD
cc: David S. Briley, P.E (ARCADIS, 801 Corporate Center Drive, Suite 300, Raleigh, NC 27607)
Wrrituck County Planning/Inspection
ashington Regional Office
North Carolina Division of Water Quality Internet: m�vw ncwaterauality ore
943 Washington Square Mall Phone [phone]
Washington, NC 27889 Fax [phone]
ne
NorthCarolina
Naturally
An Equal Opportunity/Affirmative Action Employer — 50% Reccycledlt 0% Post Consumer Paper

State Stormwater Management Systems
Permit No. SW7071105
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
Currituck County
Mainland Water Treatment Plant RO Expansion
FOR THE
construction, operation and maintenance of a wet detention pond in compliance with the provisions of 15A NCAC
2H .1000 (hereafter 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 March 5, 2008, 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
50,415 square feet of impervious area.
3. The tract will be limited to the amount of built -upon area indicated on page 3 of this permit, and per
approved plans.
4. All stormwater collection and treatment systems must be located in either dedicated common areas or
recorded easements. The final plats for the project will be recorded showing all such required easements,
in accordance with the approved plans.
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.

State Stormwater Management Systems
Permit No. SW7071105
6. The following design criteria have been provided in the wet detention pond and must be maintained at
design condition:
a. Drainage Area, acres: 2.05
b. Total Impervious Surfaces, fiz: 50,415
C. Design Storm, inches:
1 inch
d. Pond Depth, feet:
5.50
e. TSS removal efficiency:
90%
f. Permanent Pool Elevation, FMSL:
11.50
g. Permanent Pool Surface Area, ftz:
4,262
h. Permitted Storage Volume, ft3:
4,465
i. Temporary Storage Elevation, FMSL: 12.45
j. Controlling Orifice: 1 inch
k. Permitted Forebay Volume, ft3: 1,764
I. Receiving Stream/River Basin: North river
m. Stream Index Number: 30-2
n. Classification of Water Body: SC
11. 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.
3

State Stonnwater Management Systems
Permit No. SW7071105
5. Decorative spray fountains will not be allowed in the stormwater treatment system.
6. 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.
7. 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.
8. 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.
9. Access to the stormwater facilities shall be maintained via appropriate easements at all times.
10. 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. Project name change.
C. Transfer of ownership.
d. Redesign or addition to the approved amount of built -upon area or to the drainage area.
e. 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.
f. Filling in, altering, or piping of any vegetative conveyance shown on the approved plan.
11. The permittee shall submit final site layout and grading plans for any permitted future areas shown on the
approved plans, prior to construction.
12. A copy of the approved plans and specifications shall be maintained on file by the Permittee for the life of
the permit.
13. 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
This permit is not transferable except after notice to and approval by the Director. In the event of a
change of ownership, or a name change, the permittee must submit a formal permit transfer request to
the Division of Water Quality, accompanied by a completed name/ownership change form, documentation
from the parties involved, and other supporting materials as may be appropriate. 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.
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.
13

State Stormwater Management Systems
Permit No. SW7071105
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 notify the Division any name, ownership or mailing address changes within 30 days.
Permit issued this the 5 th day of March, 2008.
NORTH CAROLINA ENVIRONMENTAL MANAGEMENT COMMISSION
forColeen H. Sullins, Director
Division of Water Quality
By Authority of the Environmental Management Commission
Permit Number SW7071105

State Stormwater Management Systems
Permit No. SW7071105
Designer's Certification
I, , 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:
SEAL
Signature
Registration Number
Date
11

State Stormwater Management Systems
Permit No. SW7071105
Certification Requirements:
1. 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 a vegetated shelf, and a forebay.
15, The required system dimensions are provided per the approved plans.
cc: NCDENR-DWQ , Washington Regional Office
Currituck County Building Inspections

DWQ USE ONLY
Date Received
Fee Paid
Permit Number
bgr- t+ a 00-7
1 1 505
QW 7a 1165
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. Applicants name (specify the name of the corporation, individual, etc. who owns the project):
2. Print Owner/Signing Official's name and title (person legally responsible for facility and compliance):
Daniel F. Scanlon, County Manager
3. Mailing Address for person listed in item 2 above:
P.O. Box 39
City:Currituck State:NC Zip:27929
Phone: (252 ) 232-2242 Fax: (252 ) 232-3551
Email:[e-mail]
4. Project Name (subdivision, facility, or establishment name - should be consistent with project name on plans,
specifications, letters, operation and maintenance agreements, etc.):
Mainland Water Treatment Plant RO Expansion - Currituck County
5. Location of Project (street address):
City: Currituck County:Currituck
6. Directions to project (from nearest major intersection):
1 mile north of intersection of US highway 158 and Mahe Road. The facility is located across Maple Road
from the Currituck County Airport
7. Latitude:36°23'50.75" Longitude:76°01'13.12" of project
8. Contact person who can answer questions about the project:
Name: David S. Briley Telephone Number: (919 ) 854-1282
Email:[e-mail]
IL PERMIT INFORMATION:
1. Specify whether project is (check one):
®New
❑Renewal ❑Modification
Form SWU-101 Version 8.07
Page I of 4

k'4 2. If this application is being submitted as the result of a renewal or modification to an existing permit, list the
existing permit number N/A and its issue date (if known)
3. Specify the type of project (check one):
❑Low Density ®High Density ❑Redevelop ❑General Permit ❑Universal SMP ❑Other
4. Additional Project Requirements (check applicable blanks):
®CAMA Major ®Sedimentation/Erosion Control ❑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.
The majority of the impervious area on the site will be treated by a wet detention basin Other impervious
areas, mainly the front parking lot and a portion of the proposed building.will be treated by erass swale in the
front of the building. A narrative describing stormwater management for this project is included in the
Stormwater Management Plan.
2. Stormwater runoff from this project drains to the Pasquotank River basin.
3. Total Site Area: 44.39 acres 4. Total Wetlands Area: 0 acres
5. 100' Wide Strip of Wetland Area: N/A acres (not applicable if no wetlands exist on site)
6. Total Project Area**: 3.70 acres 7. Project Built Upon Area: 45.5 %
8. How many drainage areas does the project have? 3_(Drainage Area 3 Attached)
9. 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 format as below.
Basin Information
Drainage Area 1
Drainage Area 2
Receiving Stream Name
North River
North River
Stream Class & Index No.
SC; No. 30-2
SC; No. 30-2
Drainage Area (so
88,925 sf
28,398 sf
Existing Impervious* Area (so
3,655 sf
121 sf
Proposed Impervious*Area (so
50,415 sf
4,200 sf
% Impervious* Area (total)
61%
15%
Impervious* Surface Area
Drainage Area 1
Drainage Area 2
On -site Buildings (so
13,400 sf
0 sf
On -site Streets (so
0 sf
0 sf
On -site Parking (so
35,426 sf
3,936 sf
On -site Sidewalks (so
890 sf
0 sf
Other on -site (so
700 sf
264 sf
Off -site (so
N/A
N/A
Total (so:
50,415 sf
4,200 sf
* Impervious area is defined as the built upon area including, but not limited to, buildings, roads, parking areas,
sidetualks, gravel areas, etc.
Form SWU-101 Version 8.07 Page 2 of 4

Basin Information
Drainage Area 3
Receiving Stream Name
North River
Stream Class & Index No.
SC; No. 30-2
Drainage Area (sf)
55,152 sf
Existing Impervious* Area (sf)
4,005 sf
Proposed Impervious* Area (sf)
10,043 sf
% Impervious* Area (total)
25%
Impervious* Surface Area
; Drainage -Area 3 ., •, !: •. `
On -site Buildings (sf)
0 sf
On -site Streets (sf)
0 sf
On -site Parkin (sf)
9,505 sf
On -site Sidewalks (sf)
335 sf
Other on -site (sf)
203 sf
Off -site (sf)
N/A
Total (sf):
10,043 sf

**Total project area shall be calculated based on the current policy regarding inclusion of wetlands in the built upon area
percentage calculation.
10. How was the off -site impervious area listed above derived? N/A
IV. DEED RESTRICTIONS AND PROTECTIVE COVENANTS
One of the following deed restrictions and protective covenants are required to be recorded for all subdivisions,
outparcels and future development prior to the sale of any lot. If lot sizes vary significantly, a table listing each lot
number, size and the allowable built -upon area for each lot must be provided as an attachment.
Form DRPC-1
High Density Commercial Subdivisions
Form DRPC-2
High Density Developments with Outparcels
Form DRPC-3
High Density Residential Subdivisions
Form DRPC-4
Low Density Commercial Subdivisions
Form DRPC-5
Low Density Residential Subdivisions
Form DRPC-6
Low Density Residential Subdivisions with Curb Outlets
By your signature below, you certify that the recorded deed restrictions and protective covenants for this
project shall include all the applicable items required in the above form, 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 State, and that they will be recorded prior to the
sale of any lot.
V. SUPPLEMENT FORMS
The applicable state stormwater management permit supplement form(s) listed below must be submitted for each
BMP specified for this project. Contact the Stormwater and General Permits Unit at [phone] for the status
and availability of these forms.
Form SW401-Low Density
Form SW401-Curb Outlet System
Form SW401-Off-Site System
Form SW401-Wet Detention Basin
Form SW401-Infiltration Basin
Form SW401-Infiltration Trench
Form SW401-Bioretention Cell
Form SW401-Level Spreader
Form SW401-Wetland
Form SW401-Grassed Swale
Form SW401-Sand Filter
Low Density Supplement
Curb Outlet System Supplement
Off -Site System Supplement
Wet Detention Basin Supplement
Infiltration Basin Supplement
Underground Infiltration Trench Supplement
Bioretention Cell Supplement
Level Spreader/Filter Strip/Restored Riparian Buffer Supplement
Constructed Wetland Supplement
Grassed Swale Supplement
Sand Filter Supplement
Form SWU-101 Version 8.07 Page 3 of 4

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. The complete application package should be
submitted to the appropriate DWQ Office. (Appropriate office may be found by locating project on the
interactive online map at http://h2o.enr.state.nc.us/su/msi maps.htm)
1. Please indicate that you have provided the following required information by initialing in the space provided
next to each item.
Initials
• Original and one copy of the Stormwater Management Permit Application Form y56
• Original and one copy of the Deed Restrictions & Protective Covenants Formij
• Original of the applicable Supplement Form(s) and O&M agreement(s) for each BMPl3
• Permit application processing fee of $505 ($4,000 for Express) payable to NCDENR ; 5D
• Calculations & detailed narrative description of stormwater treatment/management -Mrs
• Copy of any applicable soil report p5tm
• Three copies of plans and specifications (sealed, signed & dated), including:
- Development/Project name
- Engineer and firm
- Legend
- North arrow
- Scale
- Revision number & date
- Mean high water line
- Dimensioned property/project boundary
- Location map with named streets or NCSR numbers
- Original contours, proposed contours, spot elevations, finished floor elevations
- Details of roads, drainage features, collection systems, and stormwater control measures
- Wetlands delineated, or a note on plans that none exist
- Existing drainage (including off -site), drainage easements, pipe sizes, runoff calculations
- Drainage areas delineated
- Vegetated buffers (where required)
VIL AGENT AUTHORIZATION
If you wish to designate authority to another individual or firm so that they may provide information on your
behalf, please complete this section.
Designated agent (individual or firm): ARCADIS
Mailing Address: 801 Corporate Center Drive Suite 300
City: Raleigh State: NC Zip: 27607
Phone: ( 919 1 854-1282 Fax: ( 919 1 854-5448
Email- dev:d. bc: �e a�cadi_vs. to ,
VIII. APPLICANT'S CERTIFICATION
I, (print or hype name of person listed in General Information, item 2) Daniel F. Scanlon
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 15A
NCAt,9I-I rnnn
Date: —LC) -
Form SWU-101 Version 8.07 Page 4 of 4

ARCADIS
Infrastructure, environment facilities
Imagine the result
STORMWATER
MANAGEMENT PLAN
Mainland Water Treatment Plant RO
Expansion
Currituck County, NC
November, 2007

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ACADIS
Infrastructure, environment facilities
Imagine the result
Stormwater Management Plan
Mainland Water Treatment
Plant
Currituck County, NC
Prepared fm
North Carolina Department of
Environmental & Natural Resources -Water
Quality Division
Prepared by
ARCADIS G&M of North Carolina, Inc.
801 Corporate Center Drive
Suite 300
Raleigh
North Carolina 27607-5073
Tel [phone]
Fax [phone]
Our Rd
NC706021.2000
Date
November 12, 2007
This document is intended only for the use
of the individual or entity for which it was
prepared and may contain information that
is privileged, confidential, and exempt from
disclosure under applicable law. Any
dissemination, distribution, or copying of
this document is strictly prohibited.

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1. Summary
2. Stormwater Management
3. Design Calculations
3.1 SA/DA Calculation / 1" Volume Calculation
3.2 Pond Volumes Worksheet
3.3 Pond Routing Calculations
3.4 Minimum Drain Time Calculations
4. Specifications
4.1 Section 02410 — Stormwater Permit for Construction Activities
4.2 Section 02720 — Storm Drainage System
5. Drawing List
5.1 C104 — Erosion/Sedimentation Control and Grading Plan
5.2 C105 — Storm Water Pond Details
2-1
3-1
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5-1
Table of Contents
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Mainland Water
Treatment Plant
Stormwater Management
Narrative
1. Summary
The proposed project is the construction of an expansion to the existing Mainland
Water Treatment Plant in Currituck County, North Carolina. The site currently has
two buildings on -site, one 6,230 sf and the other 4,000 sf with an existing IS space
parking lot and some gravel drives and parking areas. The proposed project consists of
a new building, approximately 14,000 sf, with associated parking and drives. Not all
of the expansion will add new impervious area to the site, as some of the new
construction and impervious areas will be built over existing impervious areas.
The site is located on Maple Road (SR 1246) near the Currituck County airport. It is
located in the Pasquotank river basin. The topography of the site is mainly flat, with a
portion of the site draining toward the front of the site to the roadside ditch along
Maple Road while the remainder of the site drains toward the back of the property.
2. Stormwater Management
The proposed expansion is treated as a high -density pocket of impervious areas and the
runoff will therefore treated by an approved stormwater management device. Most of
the new site construction, and a portion of the existing facility will be drained into a
stormwater detention basin. This basin will store the first 1" of run-off and release it
over a period of 2 to 5 days. Impervious areas that will not drain to the pond will drain
through grassed swales and the existing roadside ditch before leaving the site.
Drainage from the grassed swales and roadside ditch ultimately feeds into the East
Canal on the western side of the site.
The proposed building does include a future expansion. Anticipating this future
development, drainage patterns and the Stormwater pond were designed accordingly.
This additional impervious area is included in all calculations and application forms.
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Stormwater
Management Plan
MAINLAND WATER
TREATMENT PLANT RO
EXPANSION
3. Design Calculations
3.1 SA/DA Calculation / 1" Volume Calculation
3.2 Pond Volumes Worksheet
3.3 Pond Routing Calculations
3.4 Minimum Drain Time Calculations
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Mainland Water Treatment Plant - Pond Volumes
Al*A2 Volume (cf) Cumulative Volume (cf)
0
26.33 ,fit
20303
159.50
127472
370.01
422592
666.02
1135716
541.78
Pond Volume - Permanent Pool (Main Basin and Forebay)
26.33
185.83
555.84
1221.86
1763.65 Total Volume
Elevation
Area (SF)
Al *A2
Volume (cf)
Cumulative Volume (cf)
6
128
t
7
517
66176
300.75
�ti` .ti
300.75
8
904
467368
701.55
�
1002.30
9
1450
1310800
1166.30
2168.60
10
2117
30696SO
1773.01
����
3941.61
11
2154
4560018
2135.47
tip^
6077.08
11.5
t}262.
6309066
1265.80
r
7342.88 Total Volume
Pond Volume - Temporary Pool
Elevation Area (SF) Al*A2 Volume (cf) Cumulative Volume (cf)
11s � ti�5
12 8>5 24229470 2478.22 �� 2478.22
13 37657440 6148.52 \,Q S 8626.75
14 :.41 50282784 7102.01 V�� 15728.76 Total Volume
Incremental Volume was calculated by the Conic Method for Reservoir Volumes:
1 /3-(EL2-EL1)-(Area 1 +Area2+sq.rt. (Areal *Area2))
where:
EL 1, EL2 = Lower and upper elevations of the increment
Areal, Area2 = Areas computed for ELI, EL2, respectively
Volume =Incremental volume between EL1 and EL2
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NCDENR Stormwater BMP Manual Chapter Revised 09-28-07
3.5.2. Orifice Equation
The basic equation for orifices is:
Q = CD,q 2gH
Where: Q = Discharge (cfs)
CD = Coefficient of discharge (dimensionless) - see Table 3-8
A = Cross -sectional area of flow at the orifice entrance (sq ft)
g = Acceleration of gravity (32.2 ft/secz)
Ho = Driving head (ft), measured from the centroid of the orifice area to
the water surface - Note: Usually use Ho/3 to compute
drawdown through an orifice to reflect the fact that head is
decreasing as the drawdown occurs.
Figure 3-2
Schematic section through an orifice
p .....:. .:: .m =::: _I_ Q
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Table 3-8
Values of Coefficient of Discharge, CD (Malcom,1989)
Entrance Condition
Typical default value 0.60
Square -edged entrance 0.59
Concrete pipe, grooved end 0.65
Corrugated metal pipe, mitred to slope 0.52
Corrugated metal pipe, projecting from fill 1.00
Stormwater Management and Calculations 3-11 July 2007

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Project Name.
Mainland Water Treatment Plant
Project #
706021
Date:
2/7/2008
Structure NAME:
Wet Pond Riser
;v=,GIVENVALUESa^':-';•;
;'._
_ ="_CALCULATIONS__=,.-_°_',;_ .
Top Elev. of Riser (ft)
13.75
VB = 330.6 ft3
Bottom Elev. of Riser (ft)
5.50
Outside Width of Riser' (ft)
6.33
FB = 20,627 Ibs
Outside Length of Riser' (ft)
6.33
*Wall thickness included
FB(w/ F.O.S.) = c 25,784`lbs ,
FACTOR OF SAFETY
1.25
Elev. Of Rect. Orifice (ft)
12.45
Inside Width of Riser (ft)
5
Inside Length of Riser (ft)
5
Vshell = 278.5 ft3
Vvoid = 173.8 ft3
Vnser = Vshell - Vvoid= _ 104.7 ft3
Friser = 9,174 Ibs
Height of Conc. Top (ft)
Width of Conc. Base (ft)
0.5
8
Vconc top = 20.0 ft3
Fconc.to = 3,005 Ibs
Length of Conc. Base (ft)
8
Height of Conc. Base (ft)
Elev. Of the Soil above Base(ft)
1
6.00
Vbase = 64.0 (ft)
Fbase = 5,606 Ibs
Height of Concrete Fill (ft)
V = Volume
F = Force
6.00
Vconc. fill = 150.0 ft3
Fconc.fill = 22,500 Ibs
Buoyance of Water
62.4 Ibs1ft3
150 Ibsfft3
45 IbSfft3
Vsoil = 12.0 (ft)
Fsoil = 538 Ibs
Buoyance of Satur. Conc.
Buoyance of Soil
TOTAL Force = Friser + Fconc.top + Fbase + Fsoil+ Fconc.fill
TOTAL Force = 40,824 Ibs
Is The TOTAL FORCE > FB??I YES-�

Mainland Water Treatment Plant - Pond Volumes
Forebay
Elevation Area (SF)
Al *A2
Volume (cf)
Cumulative Volume (cf)
7x=-=;0
h'a = 8 - - 196
0
65.33
65.33
9 ` 065
71540
276.16
341.49
10465
206225
461.37
802.86
11 �88 68
490420
711.10
1513.96
11.5
1170932
549.85
2063.81 Total Volume
Pond Volume - Permanent Pool (Main Basin and Forebay)
Elevation Area (SF) Al *A2 Volume (cf) Cumulative Volume (cf)
6 128
7
873
111744
445.09
445.09
8
1330
1161090
1093.51
1538.61
9
1792
2383360
1555.27
3093.88
10
2317
4152064
2048.89
5142.77
11
2154
4990818
2235.00
7377.77
11.5
2929
6309066
1265.80
8643.57 Total Volume
Pond Volume - Temporary Pool
Elevation
Area (SF)
Al*A2
11.5
'r� ;s� 4262
12
�y.:��=.;ram
„ 5685
24229470
13
s 6624
37657440
14
.,. �7591•
50282784
Volume (cf) Cumulative Volume (cf)
2478.22 2478.22
6148.52 8626.75
7102.01 15728.76 Total Volume
Incremental Volume was calculated by the Conic Method for Reservoir Volumes:
1/3`(EL2-EL1)*(Areal+Area2+sq.rt. (Areal "Area2))
where:
EL1, EL2 = Lower and upper elevations of the increment
Areal, Area2 = Areas computed for EL1, EL2, respectively
Volume =Incremental volume between EL1 and EL2
G:\WWM\706021-MainlandWTP\2000-Final Design\LNR\MWTF-PondVolumes-Rev5Feb08.xls 2/7/2008

O�OF ,, O
Michael F. Easley, Governor
0
William G. Ross Jr., Secretary
North Carolina Department of Environment and Natural Resources
Collin H. Sullins, Director
Division of Water Oualitv
November 21, 2007
Mr. Eric Weatherly, County Engineer
County of Currituck
P.O. Box 38
Currituck, NC 27929
Subject: Request for Stormwater Application
Stormwater Review SW7071105
Mainland Reverse Osmosis WTP Expansion
Currituck County
Dear Mr. Weatherly:
This office received a copy of your Sedimentation and Erosion Control Plan application and plans for the
subject project located in Currituck County on November 21, 2007. North Carolina Administrative Code 15 NCAC
21-1.1000 requires that any project located in a coastal County that must receive either a Sedimentation and
Erosion Control Plan approval and/or a CAMA Major permit apply for and receive a Stormwater Management
Permit by the Division of Water Quality.
To obtain a Stormwater Permit you must submit a completed application, application fee of $505.00, two
sets of plans and specifications showing the proposed project and all stormwater treatment units along with
engineering calculations, soils report and a narrative description. The application package should be received by
this office prior to December 21, 2007. If an application package is not received by this date we will consider the
project incomplete. VVe also have an Express Permitting program. If you are interested in this program you may
contact Ms. Lyn Hardison, One Stop Permit Coordinator, at 252-948-3842.
Any development of the site prior to receipt of the required permit will constitute a violation of 15A NCAC
21-1.1000 and North Carolina General Statute 143-215.1 and may result in appropriate enforcement action
including civil penalty assessment of up to $25,000 per day.
If you have questions, please feel free to contact me at [phone].
Sincerely,
oFK/Thorpe
Environmental Engineer
Washington Regional Office
cc: ✓Washington Regional Office
Doug Huggett, CAMA
Arcadis
North Carolina Division of Water Quality Internet. �•.+���na�••acrut�,i��n grn
943 Washington Square Mall Phone [phone]
Washington, NC 27889 Far [phone]
NorthCarolina
Naturally
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